ASTIS - Arctic Science and Technology Information System


A search of the ASTIS database for "bi cases" has found the following 350 records, which are sorted by first author.


CASES2003, Leg 8 (0305) CCGS Amundsen cruise & preliminary data report June 23 - August 5, 2004
Québec, Québec : Université Laval, 2004.
[84] p. : ill., map ; 28 cm.
Cover title.
Indexed a PDF file from the Web.
References.
ASTIS record 74426.
Languages: English
Web: http://www.cases.quebec-ocean.ulaval.ca/CASES0304_leg8_cruise_report.pdf

This report describes the scientific studies carried out in Leg 8 of the CCGS Amundsen cruise, which included: 1. Rosette/MVP Operations Report; 2. Ice-atmosphere Interactions and Biological Linkages; 2.1 Surface meteorology / exhanges & Satellite validation; 2.1.1 Sea ice physical, optical and radiative properties (Ice Raids); 2.1.2 Surface EM measurements; 2.1.3 Aerial Survey; 2.2 Shipboard measurements of snow and ice reflectivity; 2.2.1 HEHSI Optics; 2.2.2 HEHSI Measurements; 2.2.3 HEHSI Field Calibration; 2.2.4 Data processing; 2.2.5 CASES cruise of the Amundsen; 2.2.6 Examples of data; Nutrients and New Production; Phytoplankton dynamics and microphytobenthos characteristics in the Cape Bathurst polynya and on the Mackenzie continental shelf; Marine Optics; Microbial ecology; Zooplankton / Young-Fish Team report CASES 03/04 Leg 8; 6.2 Water column carbon geochemistry; Early diagenesis; Bathymetric and Geophysical Data Collection; Millenial-decadal variability in sea ice and carbon fluxes. (ASTIS)

D, G, E, J, L, F, B, H, I, A
Aerial surveys; Amundsen (Ship); Bathymetry; Benthos; Biological sampling; Biomass; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chemical oceanography; Chemical properties; Cores; Geochemistry; Ice cover; Instruments; Light; Measurement; Meteorology; Microbial ecology; Ocean-atmosphere interaction; Oceanography; Optical properties; Palaeohydrology; Phytoplankton; Primary production (Biology); Remote sensing; Salinity; Sea ice; Sea water; Snow; Submarine topography; Suspended solids; Temporal variations

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Canadian Arctic Shelf Exchange Study 2005/2006 general meeting, The Inn at the Forks, Winnipeg, MB, Canada, February 13-16, 2006
[Québec] : CASES, 2006.
xiii, 36 p. ; 28 cm.
Indexed a PDF file from the Web.
Cover title.
ASTIS record 60575.
Languages: English
Web: http://www.cases.quebec-ocean.ulaval.ca/CASES06_detailed_agenda_Final.pdf

The 2005-06 CASES general meeting, hosted by the Centre for Earth Observation Science (University of Manitoba) in collaboration with the Université Laval (Québec), was held at the Inn at the Forks, Winnipeg, Manitoba from 13 to 16 February 2006. The Schools on Board program also held their Arctic Climate Change forum on February 13 with the participation of several CASES scientists and graduate students. The meeting was a great success, with over 115 participants and more than 90 posters and talks presented. The meeting attracted the attention of the media and numerous interviews were given. This meeting represented a unique opportunity to discover first hand the highlights and key findings of this research program that will provide some of the tools necessary to better predict the impact of climate change on the Canadian Arctic. An electronic copy of the detailed agenda and electronic versions of the presentations are available for download. (Au)

D, G, F, J, E, I, H, B, C
Arctic cod; Benthos; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Climate change; Food chain; Heat transmission; Marine biology; Marine ecology; Mathematical models; Melting; Microbial ecology; Ocean temperature; Ocean-atmosphere interaction; Oceanography; Permafrost; Phytoplankton; Pollution; Polynyas; Primary production (Biology); Runoff; Sea ice; Seasonal variations; Stratigraphy; Suspended solids; Temporal variations; Water masses

G07, G0815, G03, G0812
Amundsen Gulf, N.W.T.; Arctic Ocean; Franklin Bay, N.W.T.; Mackenzie Delta, N.W.T.; Mackenzie River, N.W.T.


Canadian Arctic Shelf Exchange Study : The Canadian Arctic Shelf Exchange Study 2006/2007 general meeting, Château Laurier, Québec City, 30 April to 02 May 2007
[Québec] : CASES, 2007.
vii, 20 p. ; 28 cm.
Indexed a PDF file from the Web.
Cover title.
ASTIS record 63193.
Languages: English
Web: http://www.cases.quebec-ocean.ulaval.ca/CASES06-07_AGENDA_final.pdf

The 2006-07 CASES general meeting, hosted by the Université Laval, was held from 30 April to 02 May 2007 at the Château Laurier in Québec City. Presentations at this final meeting of the research network were divided into themes, some of which were inspired by the special issues; these were: 1- Sea ice and life; 2- Annual and interannual cycles; 3- Carbon and climate; and 4- Modelling and other. In celebration of the successful conclusion of CASES, a student poster competition, supported by the Department of Fisheries and Oceans, was held. The three winners of this competition are: 1st ($500): Alexandre Forest, Université Laval; 2nd ($400): Sélima BenMustapha, Université de Sherbrooke; 3rd ($300): Gérald Darnis, Université Laval. (Au)

D, G, F, J, E, I, H, B, C
Arctic cod; Benthos; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Climate change; Food chain; Heat transmission; Marine biology; Marine ecology; Mathematical models; Melting; Microbial ecology; Ocean temperature; Ocean-atmosphere interaction; Oceanography; Passive microwave remote sensing; Permafrost; Phytoplankton; Pollution; Polynyas; Primary production (Biology); Rivers; Runoff; Sea ice; Sea ice ecology; Seasonal variations; Snow; Stratigraphy; Surface properties; Suspended solids; Temporal variations; Water masses

G07, G0815, G03, G0812
Amundsen Gulf, N.W.T.; Arctic Ocean; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Delta, N.W.T.; Mackenzie River, N.W.T.


The benthic environment   /   Aitken, A.E.   Conlan, K.   Renaud, P.E.   Hendrycks, E.   McClelland, C.   Archambault, P.   Cusson, M.   Morata, N.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 9, p. 159-199, ill., maps
References.
ASTIS record 67492.
Languages: English
Libraries: ACU

... Given regional differences in sea ice cover, carbon supply, riverine influence, sedimentation, and upwelling throughout the Beaufort Sea Shelf region, we can hypothesize the following regarding the structure and respiration of its benthic community: 1. The composition of the benthic community within the Cape Bathurst polynya (Amundsen Gulf) is distinctive from its immediate surroundings at similar depth; 2. The composition of the benthic community is likely distinctive in upwelling regions like Cape Bathurst and the Mackenzie Canyon; 3. The Beaufort Shelf possesses a cross-shelf gradient in benthic community composition associated with depth-related changes in ice cover, ice scour, water masses (including input from the Mackenzie River), and upwelling at the shelf edge; 4. The respiration of the benthic community in the region reflects the seasonality of local sea ice, water mass input, and circulation/mixing cycles. ... Nine regions within the Beaufort Shelf and Amundsen Gulf study area ... were identified based on geography and ice regime ...: The Mackenzie Canyon offshore of the Mackenzie delta; the Beaufort Shelf encompassing the inshore fast ice area (<20 m depth); the flaw lead (20-35 m); the main part of the shelf (>35 m to 200 m); the slope (>200 m); and four regions in Amundsen Gulf (Cape Bathurst, the Cape Bathurst polynya, Franklin Bay and the part of the gulf sampled east of the polynya). Sampling occurred over six ship cruises in 2002-2004. CCGS Sir Wilfrid Laurier samples were collected in Sept 2002; CCGS Radisson samples in Oct 2002; and CCGS Amundsen (Legs 1, 2, 6 and 8) samples in Sept-Oct 2003, Oct-Nov 2003, April 2004 and July 2004 (respectively). A 0.25 m² box corer was used for sampling aboard CCGS Radisson and CCGS Amundsen and a 0.1 m² van Veen grab was used aboard CCGS Laurier. ... Macrofauna were elutriated from the sediment .... Organisms traditionally considered meiofauna ... were excluded from the data. ... Bottom water characteristics were measured at the time of faunal and sediment collection. Seasonal variation in temperature, salinity and current speed were recorded from fixed moorings .... Macrofauna which characterized each of the 9 regions of the study area are listed .... Polychaetes dominated the communities .... Based on the relative abundance of taxa, the benthic community beneath the polynya did not differ significantly from adjacent communities in Amundsen Gulf East, Franklin Bay and Cape Bathurst .... The species composition of the polynya was significantly different from the distant Beaufort Shelf and inshore regions. However, it did not differ significantly from communities on the Beaufort slope and in the Mackenzie Canyon. ... The most significant difference between the polynya community and that of the main Beaufort Shelf lay in the relative abundance of several large fauna .... both the structure and seasonal activity of benthic faunal communities as well as primary productivity determine carbon preservation and nutrient regeneration patterns on Arctic shelves. ... In the context of rapid climate warming, it has become imperative to dcument more temporal variations in bottom community structure and respiration to form a baseline from which future changes can be assessed. ... (Au)

I, J, B, D, G, H
Algae; Amphipoda; Animal distribution; Animal respiration; Bathymetry; Benthos; Biological productivity; Biological sampling; Biomass; Bottom sediments; Carbon; Chlorophyll; Clay; Cores; Crustacea; Fast ice; Ice leads; Isopoda; Isotopes; Lamellibranchiata ; Marine biology; Nitrogen; Ocean currents; Ocean temperature; Ostracoda; Oxygen; Polychaeta ; Polynyas; Salinity; Sand; Seasonal variations; Silt; Size; Spatial distribution; Velocity; Water masses; Wildlife habitat

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Winter-to-summer changes in the composition and single-cell activity of near-surface Arctic prokaryotes   /   Alonso-Sáez, L.   Sánchez, O.   Gasol, J.M.   Balagué, V.   Pedrós-Alió, C.
(Environmental microbiology, v. 10, no. 9, Sept. 2008, p.2444-2454, ill.)
References.
ASTIS record 65877.
Languages: English
Web: doi:10.1111/j.1462-2920.2008.01674.x
Libraries: ACU

We collected surface samples in Franklin Bay (Western Arctic) from ice-covered to ice-free conditions, to determine seasonal changes in the identity and in situ activity of the prokaryotic assemblages. Catalysed reported fluorescence in situ hybridization was used to quantify the abundance of different groups, and combined with microautoradiography to determine the fraction of active cells taking up three substrates: glucose, amino acids and ATP. In surface waters, Archaea accounted for 16% of the total cell count in winter, but decreased to almost undetectable levels in summer, when Bacteria made up 97% of the total cell count. Alphaproteobacteria were the most abundant group followed by Bacteroidetes (average of 34% and 14% of total cell counts respectively). Some bacterial groups appearing in low abundances (<10% of total cell counts), such as Betaproteobacteria, Roseobacter and Gammaproteobacteria, showed a high percentage of active cells. By contrast, more abundant groups, such as SAR11 or Bacteroidetes, had a lower percentage of active cells in the uptake of the substrates tested. Archaea showed low heterotrophic activity throughout the year. In comparison with temperate oceans, the percentage of active Bacteria in the uptake of the substrates was relatively high, even during the winter season. (Au)

H, J, D
Amino acids; Archaea; Bacteria; Biological sampling; Carbon; Chlorophyll; Fluorometry; Marine ecology; Metabolism; Microbial ecology; Microorganisms; Ocean temperature; Plant distribution; Seasonal variations; Sugars

G0815
Franklin Bay, N.W.T.


Terrestrial and marine POC fluxes derived from 234Th distributions and delta 13C measurements on the Mackenzie shelf   /   Amiel, D.   Cochran, J.K. [Supervisor]
Stony Brook, N.Y. : State University of New York at Stony Brook, 2007.
ix, 120 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. 3301476)
ISBN 9780549472131
Appendix.
References.
Thesis (Ph.D.) - State University of New York, Stony Brook, N.Y., 2007.
Indexed a PDF file from the Web.
ASTIS record 64586.
Languages: English
Web: http://dspace.sunyconnect.suny.edu/bitstream/1951/43040/1/100008124.sbu.pdf
Libraries: ACU

Water column deficits of 234Th relative to 238U in the Mackenzie shelf, Cape Bathurst Polynya and Amundsen Gulf were used to estimate sinking fluxes of POC [particulate organic carbon] in these areas. 234Th fluxes were converted to marine and terrestrial POC fluxes using the POC/Th ratio on filterable particles >70 µm and delta 13C measurements to determine the fraction of marine and terrestrial POC. In June/July 2004, the greatest 234Th deficits (0-100 m: 56-95 dpm/m²) were observed in the Mackenzie outer shelf. Deficits in the upper 100 m ranged from 3-59 dpm/m² in the Cape Bathurst Polynya. delta 13C values of POC in the >70 µm particles filtered in situ pumps ranged from -25.1‰ to -28‰. Using a two-end member mixing model with marine POC=-21.4‰ and terrestrial POC=-28‰ shows that terrestrial POC is most evident at the Mackenzie shelf stations but is present throughout the region. The fraction of marine POC ranged from 0 to 59% in the area in June/July 2004, with the highest values in the Amundsen Gulf. Fluxes of marine POC in the polynya average ~5 mmol C/m²/d at 50 m in June 2004 and increase to ~12 mmol C/m²/d in July. Comparable fluxes are observed at 100 m in June, but values decrease to ~6 mmol C/m²/d at 100 m in July. These fluxes are greater than estimates of organic carbon remineralization and burial in sediments of the polynya (~3 mmol/m²/d), suggesting that POC may be exported out of the area, effectively remineralized by microbial activity in the twilight zone or incorporated into biomass. (Au)

D, H, F, G, B, A
Algae; Biomass; Bottom sediments; Carbon; Carbon cycling; Cesium; Chlorophyll; Continental shelves; Cores; Density; Estuaries; Fluorometry; Ice cover; Ice leads; Isotopes; Lead; Mass balance; Mass spectrometry; Phytoplankton; Plant nutrition; Polynyas; Primary production (Biology); Radionuclides; Radon; River discharges; Salinity; Sea ice; Seasonal variations; Sediment transport; Sedimentation; Size; Spatial distribution; Suspended solids; Theses; Thorium; Uranium; Water masses

G07, G0815
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Bathurst, Cape, waters, N.W.T.; Franklin Bay, N.W.T.; Kugmallit Bay, N.W.T.; Mackenzie Bay, N.W.T./Yukon


Terrestrial and marine POC fluxes derived from 234Th distributions and delta 13C measurements on the Mackenzie shelf   /   Amiel, D.   Cochran, J.K.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C3, C03S06, Mar. 2008, 19 p., ill., maps)
(Contribution - State University of New York at Stony Brook. Marine Sciences Research Center, 1351)
References.
ASTIS record 64125.
Languages: English
Web: doi:10.1029/2007JC004260
Libraries: ACU

Water column deficits of 234Th relative to 238U in the Mackenzie Shelf, Cape Bathurst Polynya, and Amundsen Gulf were used to estimate sinking fluxes of particulate organic carbon (POC) in these areas. The 234Th fluxes were converted to marine and terrestrial POC fluxes using the POC/Th ratio on filterable particles >70 µm and delta 13C measurements to determine the fraction of marine and terrestrial POC. In June/July 2004, the greatest 234Th deficits (0-100 m: 56-95 dpm/m²) were observed in the Mackenzie outer shelf. Deficits in the upper 100 m ranged from 3 to 59 dpm/m² in the Cape Bathurst Polynya. The delta 13C values of POC in the >70-µm particles filtered in situ pumps ranged from -25.1‰ to -28‰. Using a two-end-member mixing model with marine POC = -21.4‰ and terrestrial POC = -28‰ shows that terrestrial POC is most evident at the Mackenzie Shelf stations but is present throughout the region. The fraction of marine POC ranged from 0 to 59% in the area in June/July 2004, with highest values in the Cape Bathurst Polynya. Fluxes of marine POC in the polynya average ~5 mmol C /m²/d at 50 m in June 2004 and increase to ~12 mmol C/m²/d in July. Comparable fluxes are observed at 100 m in June, but values decrease to ~6 mmol C/m²/d at 100 m in July. These fluxes are greater than estimates of organic carbon remineralization and burial in sediments of the polynya (~3 mmol/m²/d), suggesting that POC may be exported out of the area, effectively remineralized by microbial activity in the twilight zone or incorporated into biomass. (Au)

J, D, H, F, B, G
Algae; Bathymetry; Biomass; Bottom sediments; Carbon; Carbon cycling; Carbon dioxide; Continental shelves; Cores; Food chain; Isotopes; Marine ecology; Mathematical models; Oceanographic instruments; Oceanography; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Polynyas; Primary production (Biology); Rivers; Sea ice; Sediment transport; Spatial distribution; Suspended solids; Temporal variations; Thorium; Trophic levels; Uranium; Water masses

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Bathurst, Cape, waters, N.W.T.; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.


Geometrical constraints on the evolution of ridged sea ice   /   Amundrud, T.L.   Melling, H.   Ingram, R.G.
(Journal of geophysical research, v.109, no. 6, C06005, June 2004, 12 p., ill., map)
References.
ASTIS record 63202.
Languages: English
Web: doi:10.1029/2003JC002251
Libraries: ACU

A numerical model of the evolving draft distribution of seasonal pack ice is driven by freezing and ice field compression in one dimension. Spatial transects of sea ice draft acquired during winter in the Beaufort Sea are used to evaluate the model. Histograms obtained by ice-profiling sonar on subsea moorings reveal changes in the draft distribution, while observations of ice velocity by Doppler sonar allow calculation of the strain to which the draft distribution is responding. Numerical diffusion in thermal ice growth is controlled using a remapping algorithm. Mechanical redistribution algorithms in common use generate much more deep ridged ice than is observed. Geometric constraints on ridge-keel development that reflect the finite extent of level floes available for ridge building and the true average shape of keels produce more realistic results. In the seasonal pack ice of the Beaufort Sea, 75% of all floes are too small to provide a volume of ice sufficient to construct a keel of draft equal to that commonly assumed in ice dynamics modeling. On average, the distribution of draft within keels has a negative exponential form, implying a cusped keel shape with more area on the thinner flanks than at the crest; models commonly assume a uniform redistribution of ice into a keel of triangular shape. Clearly, the spatial organization of ice within seasonal pack or, equivalently, the existence of ridges and floes should be an acknowledged factor in redistribution theory for pack ice thickness. (Au)

G, D, E, J
Buckling (Mechanics); Chemical oceanography; Climate change; Deformation; Draft; Dynamic properties; Effects of climate on ice; Fast ice; Formation; Ice floes; Ice forecasting; Ice leads; Mathematical models; Melting; Ocean-atmosphere interaction; Pack ice; Pressure ridges; Sea ice; Seasonal variations; Size; Sonar; Strain; Temporal variations; Thermodynamics; Thickness; Velocity; Winds

G07, G03
Arctic Ocean; Canadian Beaufort Sea


Geometrical constraints on the formation and melt of ridged sea ice   /   Amundrud, T.L.   Ingram, G. [Supervisor]   Melling, H. [Co-supervisor]
Vancouver, B.C. : University of British Columbia, 2004.
xviii, 165 p. : ill., map ; 28 cm.
Thesis (Ph.D.) - Univesity of Vancouver, Vancouver, B.C., 2004.
Appendices.
References.
ASTIS record 74968.
Languages: English
Web: http://hdl.handle.net/2429/16976
Libraries: BVAU

The Arctic ice pack consists of flat level ice, open water, and large ridge structures. During winter, ice thickens and is compacted into ridges, increasing the Arctic ice volume. In summer, ridging is accompanied by ice melt processes, which act to decrease ice volume. Current ice-atmosphere-ocean models cannot reproduce the evolution of the ridged ice fraction, suggesting that ridging or melt may be inappropriately parameterized. To increase our understanding of ridged ice evolution, this thesis investigates the factors that constrain the ridging and melt processes. A unique ice draft distribution model is developed to simulate ice evolution in the Beaufort Sea, allowing direct comparison with observations of ice draft by moored sonar. Conventional ridging algorithms used in a 24-day simulation were found to overestimate the amount of very thick ice. Observations of level ice reveals that 75% of all ice floes are too small to create ridges of maximum draft. In addition, observed ridges have cusp-shaped keels with concave flanks, containing less thick ice and increased amounts of thinner ice than the triangular shaped keels assumed by most models. Including the observed constraints into the redistribution model produces ridged ice in agreement with observations, confirming the importance of the geometrical constraints to the creation of ridged ice. During the melt season, simulations of ice ablation in the Beaufort Sea indicate that level ice melt processes cannot reproduce the observed enhanced melt rates of ridged ice. A semi-quantitative model for internal melt due to flow through the porous keel is developed and an enhanced internal melt rate estimated. The rate of melting within the porous structure of the ridge keel is up to an order of magnitude greater than the rate of melting at the surface of level ice floes. Including the internal melt within the ice draft distribution model can reproduce the enhanced melt of ridged ice and is thus essential for the accurate simulation of the evolution of ridged ice. Similar to the geometric constraints on ice ridging, the internal geometry of ridge keels plays a large role in the annual evolution of the thickest sea ice. (Au)

G, D, E, J
Ablation; Buckling (Mechanics); Chemical oceanography; Climate change; Deformation; Density; Draft; Dynamic properties; Effects of climate on ice; Fast ice; Formation; Ice cover; Ice floes; Ice forecasting; Ice leads; Ice rubble fields; Mathematical models; Mechanical properties; Melting; Ocean temperature; Ocean-atmosphere interaction; Pack ice; Pressure ridges; Salinity; Sea ice; Seasonal variations; Size; Sonar; Strain; Temporal variations; Thermodynamics; Theses; Thickness; Velocity; Winds

G07, G03
Arctic Ocean; Canadian Beaufort Sea


The effect of structural porosity on the ablation of sea ice ridges   /   Amundrud, T.L.   Melling, H.   Ingram, R.G.   Allen, S.E.
(Journal of geophysical research, v.111, no. 6, C06004, June 2006, 14 p., ill., map)
References.
ASTIS record 63203.
Languages: English
Web: doi:10.1029/2005JC002895
Libraries: ACU

Observations reveal that the decrease in ice thickness through melting in summer is much more rapid for ridges than for surrounding level ice. A physical model that represents internal melting within ridge keels has been developed to explain this observed draft-dependent ablation for first-year pack ice in the Beaufort Sea. The porous structure of a ridge keel permits percolation of a substantial fraction of the oncoming oceanic flow, up to 20% for a feature with 30% porosity and 9-m draft. The percolating flow delivers oceanic heat to a large surface area deep within the keel and increases melt rates relative to surrounding level ice by a factor of 5 when seawater temperatures are 0.18° above freezing. Melt rates are sensitive to the internal geometry of ridges through keel porosity and block dimensions, characteristics that vary widely between ridge features. However, the average rate of melting as a function of draft, calculated for a realistic population of keels with average cross-sectional shape and differing draft, has the same draft-dependence as the observations. This concurrence suggests that the process of internal melting may be dominant in the ablation of ridged ice. In addition, internal melting during the summer may well hasten structural consolidation of surviving ridge keels through freezing during the following winter. It appears that the evolution of the thickest ice within the Arctic ice pack is dependent on the small-scale structural characteristics of the ridged ice and its interaction with the upper layer of the ocean. (Au)

G, D, E, J
Ablation; Buckling (Mechanics); Climate change; Deformation; Density; Draft; Effects of climate on ice; Flow; Formation; Heat transmission; Ice cover; Ice floes; Ice forecasting; Mathematical models; Measurement; Melting; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Pack ice; Physical properties; Pressure ridges; Sea ice; Seasonal variations; Size; Sonar; Temporal variations; Thermal properties; Thermodynamics; Thickness; Velocity; Winds

G07
Canadian Beaufort Sea


Annual cycles of sea ice and phytoplankton in Cape Bathurst polynya, southeastern Beaufort Sea, Canadian Arctic   /   Arrigo, K.R.   van Dijken, G.L.
(Geophysical research letters, v. 31, no. 8, L08304, Apr. 2004, 4 p., ill., maps)
References.
ASTIS record 63215.
Languages: English
Web: doi:10.1029/2003GL018978
Libraries: ACU

The relationship between the dynamics of sea ice and phytoplankton abundance were investigated for the Cape Bathurst polynya region of the Canadian Arctic using five years (1998-2002) of satellite data from SSM/I and SeaWiFS. The Cape Bathurst polynya exhibited marked interannual variability in sea ice dynamics, both in the timing of initial polynya formation and in the extent and persistence of open water. Related to this, although all years exhibited two distinct phytoplankton blooms, these also varied in their intensity and timing. Generally, the late bloom of each year was the most intense, after surface waters had stratified in summer. Blooms were most intense in spring 1998, following anomalous warming and early stratification, and late summer 2002, following a summer ice melt event. Changes in the timing of phytoplankton bloom development in polar waters can impact food web structure and the relative importance of top-down versus bottom-up control of marine ecosystems. (Au)

G, H, E, D, J, I
Animal food; Arctic cod; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chlorophyll; Clouds; Diatoms; Formation; Ice cover; Marine ecology; Mathematical models; Melting; Ocean temperature; Phytoplankton; Plant growth; Plant nutrition; Polynyas; Primary production (Biology); Satellites; Sea ice; Seasonal variations; Solar radiation; Spatial distribution; Special Sensor Microwave/Imager; Stamukhi; Surface temperature; Temporal variations; Water masses; Winds

G0815, G07, G141
Barents Sea; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.; North Water Polynya, Baffin Bay; Northeast Water Polynya, Greenland Sea


Atmospheric forcing of the Beaufort Sea ice gyre : surface pressure climatology and sea ice motion   /   Asplin, M.G.   Lukovich, J.V.   Barber, D.G.
(Beaufort Gyre climate system exploration studies / Edited by A. Proshutinsky. Journal of geophysical research, v.114, C00A06, 2009, 13 p., ill., maps)
References.
Indexed a PDF file from the Web.
ASTIS record 68556.
Languages: English
Web: doi:10.1029/2008JC005127
Libraries: ACU

The Beaufort Gyre (BG) typically rotates anticyclonically and exerts an important control on Arctic Sea ice dynamics. Previous studies have shown reversals in the BG to rotate cyclonically during summer months and, in recent decades, throughout the annual cycle. In this investigation, we explore the synoptic climatology of atmospheric forcing and its relationship to sea ice motion and BG reversals. A catalog of daily synoptic weather types is generated for the Beaufort Sea Region covering the period 1979 to 2006 using NCEP/NCAR reanalysis mean sea level pressure data, principle components, and k-means cluster analyses. Mean synoptic type frequency, persistence, and duration values are calculated for each synoptic type and contrasted between the summer and winter seasons. Daily synoptic types are linked to changes in sea ice vorticity by using correlation analysis on lagged sea ice vorticity data. Lag correlations are found between synoptic types and sea ice vorticity smoothed over a 12-week running mean and show that cyclonic types, which promote southerly or easterly atmospheric circulation over the southern Beaufort Sea, commonly precede summer reversals. Furthermore, significant seasonal within-type variability in sea ice vorticity is detected within the synoptic types illustrating the importance of seasonal variability on these processes. (Au)

G, D, E
Atmosphere; Atmospheric circulation; Atmospheric pressure; Atmospheric temperature; Effects of climate on ice; Mathematical models; Movement; Ocean currents; Ocean-atmosphere interaction; Sea ice; Seasonal variations; Spatial distribution; Storms; Stratosphere; Synoptic climatology; Temporal variations; Velocity; Winds

G07, G04, G02
Arctic regions; Beaufort Sea; Chukchi Sea


Comparative analysis of photosynthetic properties in ice algae and phytoplankton inhabiting Franklin Bay, the Canadian Arctic, with those in mesophilic diatoms during CASES 03-04   /   Ban, A.   Aikawa, S.   Hattori, H.   Sasaki, H.   Sampei, M.   Kudoh, S.   Fukuchi, M.   Satoh, K.   Kashino, Y.
(Polar bioscience, v. 19, 2006, p. 11-28, ill., maps)
References.
ASTIS record 60652.
Languages: English
Libraries: ACU

Psychrophilic phytoplankton and ice algae were collected in Franklin Bay, the Canadian Arctic, in late May 2004, and the photosynthetic properties were measured at 4°C using a pulse amplitude modulation fluorometer (Phyto-PAM). Rapid light curve measurements allowed for the assessment of the photosynthetic efficiency (alpha), maximal electron transport rate (rETRmax), and minimum saturating irradiance (Ek) in the samples. The values of alpha in phytoplankton (0.63-0.68) were much larger than those in ice algae (0.10-0.51), and the values of rETRmax in phytoplankton (4.6-6.7) were relatively larger than those in ice algae (1.8-4.3). However, Ek showed similar values in both samples and were around 10 µmol photons · m**-2 · s**-1. These values were systematically compared with those obtained from mesophilic marine diatoms (a centric diatom, Chaetoceros gracilis, and a pennate diatom, Phaeodactylum tricornutum) grown under various irradiances in the laboratory. The highly shade-adapted features of ice algae and phytoplankton were disclosed through this comparative analysis. It was also found that the non-photochemical quenching was much higher in psychrophilic samples than in mesophilic diatoms grown under moderate irradiance. Furthermore, in ice algae and phytoplankton, the decrease in rETR at high irradiances was prominent, showing that they were highly susceptible to photoinhibition. Our comparative analysis using psychrophilic phytoplankton, ice algae and two strains of mesophilic diatoms also revealed that the dependency on the xanthophyll cycle for the protection mechanisms of photosystems were remarkably different between the groups, indicating that the acclimation strategies to growth irradiances were variable between species. Such variable acclimation strategies could be one of the forces that results in a diverse algal flora that enables this region around Franklin Bay to be a productive area, even though the psychrophilic phytoplankton and ice algae are highly shade-adapted. (Au)

G, H, D
Algae; Cold adaptation; Diatoms; Fluorometry; Light; Marine flora; Measurement; Photosynthesis; Phytoplankton; Plant growth; Sea ice ecology

G0815
Franklin Bay, N.W.T.


The incredible shrinking sea ice   /   Barber, D.   Fortier, L.   Byers, M.
(Global warming - a perfect storm = Au cœur de la tempête. Policy options = Options politiques, v. 27, no. 1, Dec. 2005-Jan. 2006, p. 66-71, ill.)
ASTIS record 62603.
Languages: English
Web: http://www.irpp.org/po/archive/dec05/barber.pdf
Libraries: ACU

In the disaster blockbuster, "The Day After Tomorrow," the shrinking of polar ice caused by climate change unleashes an extreme weather Armaggedon which, among other things, sees the Statue of Liberty engulfed by a tidal wave. The predictions offered here by David Barber, Louis Fortier and Michael Byers are less cataclysmic but equally compelling. In relaying the scientific evidence and outlining the ecological, economic and political impacts of polar climate change, Barber, Fortier and Byers present a chilling case for heading off doomsday. (Au)

E, G, J, I, H, L, R, T
Arctic Waters Pollution Prevention Act, 1970; Biological productivity; Canadian Coast Guard; Canadian Rangers; Climate change; Cold adaptation; Culture (Anthropology); Environmental impacts; Food chain; Government; Ice cover; Icebreakers; Inuit; Marine biology; Marine ecology; Marine transportation; Maritime law; Mathematical models; Melting; Military operations; Pack ice; Sea ice; Socio-economic effects; Sovereignty; Temporal variations; Weather forecasting

G0815
Amundsen Gulf, N.W.T.; M'Clure Strait, N.W.T.; Northwest Passage


Meteorological forcing of sea ice concentrations in the southern Beaufort Sea over the period 1979 to 2000   /   Barber, D.G.   Hanesiak, J.M.
(Journal of geophysical research, v.109, no. 6, C06014, June 2004, 16 p., ill., maps)
References.
ASTIS record 60651.
Languages: English
Web: doi:10.1029/2003JC002027
Libraries: ACU

Northern Hemisphere sea ice areal extent, and perhaps thickness, have shown a detectable reduction over the past several decades. This situation is particularly apparent in the southern Beaufort Sea. The region encompassing the Mackenzie Shelf, the Cape Bathurst Polynya, and the Canada Basin mobile pack ice all occur in a region referred to here as the Canadian Arctic Shelf Exchange study area (CASES). In this paper we present results from an analysis of atmosphere, sea ice, and ocean coupling over the period 1979 to 2000 as a means of setting a physical science context for the CASES research network (operating over the period 2001-2005). Results show that the Cape Bathurst Polynya complex can be considered as a recurrent polynya; particularly the flaw leads associated with the early opening of the polynya. The Polynya appears to be a consequence of the Beaufort Sea Gyre acting like an ice bridge and a series of flaw leads creating conditions conducive to oceanic upwelling. The sea ice average areal extent has been decreasing in this region over the period 1979 to 2000. Large regional reductions are found (1) north of the Yukon and Alaska Coasts in the region between the Canada Basin pack ice and the landfast sea ice and (2) at the eastern limit of the Cape Bathurst Polynya in Amundsen Gulf. The meteorological forcing of sea ice anomalies occurs through a full range of timescales and space scales. At hemispheric scales a statistical cross-correlation analysis between weekly sea ice concentration anomalies and the Arctic Oscillation accounts for a maximum of about 25 percent of the explained variance and show a surprising spatial coherence in correlation magnitudes both within the study area and northward along the Canadian Archipelago coast. At local scales, positive and negative concentration anomaly periods can be explained through local-scale advective processes associated with regional-scale sea level pressure, 500 hPa geopotential heights, and surface temperature anomalies. (Au)

E, G, D, J, F
Atmospheric temperature; Canadian Arctic Shelf Exchange Study; Climate change; Effects of climate on ice; Fast ice; Formation; Ice cover; Ice forecasting; Ice leads; Mathematical models; Melting; Meteorology; Ocean-atmosphere interaction; Oceanography; Pack ice; Polynyas; Remote sensing; Sea ice; Sea level; Seasonal variations; Snow; Surface temperature; Temporal variations; Thermodynamics; Thickness; Water masses; Winds

G07, G03, G0815
Amundsen Gulf, N.W.T.; Canada Basin, Arctic Ocean; Canadian Beaufort Sea


The Canadian Arctic Shelf Exchange Study (CASES)   /   Barber, D.G. [Editor]   Fortier, L. [Editor]
(CMOS bulletin = Bulletin SCMO, v. 32, no. 5, Oct. 2004, p. 131-142, ill., maps)
References.
French abstract provided.
ASTIS record 60658.
Languages: English
Libraries: ACU

The Government of Canada has recently begun to make strategic re-investments into polar research. This evolution is due in part to: a) a realization that Canada's capacity to conduct polar science declined precipitously throughout the decades of the 1980s and 1990s (Hutchinson, 2000); b) mounting evidence which shows that significant changes in the Arctic Ocean, sea ice, atmosphere and lithosphere have already begun and that these changes are connected to global scale climate variability and change (IPCC, 2001); and c) Arctic sovereignty and in particular shipping routes through Canada's north will come into question in the decades ahead. Sea ice in particular has become a focus due to the significant role ice plays in Inuit livelihood, industrial development, biogeochemical cycling and marine productivity. Given our geopolitical position as an industrialized Arctic nation, it follows that Canada should play a leadership role in understanding the consequences of a changing Arctic environment. Towards this goal, the Canadian Arctic Shelf Exchange Study (CASES) Research Network was funded (2001-2006) by the Natural Sciences and Engineering Research Council (NSERC) of Canada. CASES is an international effort, under Canadian leadership, to understand the biogeochemical and ecological consequences of sea ice variability and change on the Mackenzie Shelf. Given its scope, the CASES initiative summons a large fraction of the Canadian and foreign expertise in Arctic oceanography. In Canada, the network includes Principal Investigators (PIs) from ten Canadian universities, four Federal departments (Fisheries & Oceans, Environment, Natural Resources, Defence) and the Canadian Museum of Nature. The Canadian Coast Guard and the Polar Continental Shelf Project provide the essential logistical and navigational expertise for an Arctic endeavour of this extent. The CASES Network has merged this complementary regional expertise into a team comprising 42 Canadian Arctic researchersand over 50 Arctic specialists from 9 foreign countries (USA, Japan, UK, Denmark, Russia, Poland, Norway, Belgium, Spain). Partner funding was provided by Canadian collaborators: Fisheries and Oceans Canada, the Meteorological Service of Canada, Canada Foundation for Innovation, and the Canadian Ice Service. International funding was contributed by each of the 9 partner countries and in particular through NOM, NASA and the Japanese Polar Science program. In this article we summarize the structure of the CASES research network and report on preliminary findings from the field components of the experiment. Analysis of field data has begun and will be completed by 2007. We plan to publish our findings in forthcoming issues of ATMOSPHERE-OCEAN and other internationally recognized journals. (Au)

G, E, F, D, H, I, J, R, B
Amundsen (Ship); Animal distribution; ArcticNet Inc.; Bioaccumulation; Biological productivity; Biological sampling; Biomass; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Climate change; Education; Environmental impacts; Food chain; Hydrography; Ice scouring; Instruments; Marine ecology; Marine fauna; Marine flora; Mathematical models; Measurement; Meteorological instruments; Meteorology; Microorganisms; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Oceanographic instruments; Oceanography; Palaeoclimatology; Plankton; Pollution; Public education campaigns; Public participation; Research; Research funding; River discharges; Sea ice; Seasonal variations; Socio-economic effects; Sovereignty; Submarine topography; Suspended solids; Temporal variations; Water masses

G0812, G07, G0815
Amundsen Gulf, N.W.T.; Beaufort Sea; Franklin Bay, N.W.T.; Inuvialuit Settlement Region waters, N.W.T./Yukon; Inuvialuit Settlement Region, N.W.T./Yukon; Kugmallit Bay, N.W.T.; Mackenzie River, N.W.T.


Microwave remote sensing, sea ice and Arctic climate   /   Barber, D.G.
(Planetary remote sensing in Canada = Télédétection planétaire au Canada. Physics in Canada, v. 61, no. 5, Sept./Oct. 2005, p. 227-233, ill., maps)
References.
ASTIS record 63317.
Languages: English
Libraries: ACU

In this work we show how the temporal dimension of microwave scattering and emission can be used to develop applications for retrieval of both geophysical and thermodynamic state information of Arctic snow covered sea ice as a means of assessing Arctic climate processes. (Au)

G, F, E, A
Age; Albedo; Breakup; Climate change; Diurnal variations; Electrical properties; Electromagnetic radiation; Energy budgets; Fast ice; Formation; Growth; Heat transmission; Mass balance; Mathematical models; Melting; Ocean-atmosphere interaction; Passive microwave remote sensing; Puddles; Radar; Salinity; SAR; Sea ice; Sea water; Snow; Snow cover; Snow metamorphism; Snow water equivalent; Surface properties; Surface temperature; Temporal variations; Thermal regimes; Thermodynamics; Thickness

G02, G0815, G0814, G09, G141
Baffin Bay-Davis Strait; Barents Sea; Canadian Arctic Islands waters; Greenland waters; Hudson Bay


The role of sea ice in Arctic and Antarctic polynyas   /   Barber, D.G.   Massom, R.A.
(Polynyas : windows to the world / Edited by W.O. Smith and D.G. Barber. Elsevier oceanography series, v. 74, 2007, ch. 1, p. 1-54, ill., maps)
References.
Available in paper and through the Internet.
ASTIS record 63893.
Languages: English
Web: doi:10.1016/S0422-9894(06)74001-6
Libraries: ACU

Polynyas are persistent and recurrent regions of open water and/or thin ice or reduced ice concentration, tens to tens of thousands of square kilometers in areal extent, that occur within the sea ice zones of both hemispheres at locations where a more consolidated and thicker ice cover would be climatologically expected. Rather than simply constituting recurrent “windows” in the sea ice, polynyas are profoundly affected by, and intimately linked to, local and even regional ice conditions (i.e., the "icescape"). They respond sensitively to thermodynamic and dynamic forcing by the ocean and atmosphere and entail ecologically important "oases" that enable birds and mammals to overwinter at high latitudes and encourage enhanced primary production in the spring. In this review, we introduce the concept of polynyas from the perspective of the sea ice conditions/processes that define them. We discuss the unique characteristics of polynyas in both polar regions, and assess their possible response/contribution to climate variability and change. An inventory of Northern Hemisphere polynyas is presented, based primarily of satellite data analysis but also on information from the literature and aboriginal peoples. Summary statistics on polynya opening and closing dates are also provided, along with information on the availability of light relative to the seasonal cycles of sea ice. In the Southern Hemisphere, we present an update of an inventory of Antarctic polynyas and discuss how coastal, glacial and deep-ocean processes affect their and distribution. Two important polynyas are examined in more detail, i.e., the North Water (NOW) polynya in the north and the Mertz Glacier polynya in the south. These case studies focus on details of the different physical processes driving their creation, maintenance and dissolution. Each of these polynyas has been the focus of dedicated in situ research programmes in recent years. (Au)

G, D, E, F
Albedo; Atmospheric circulation; Atmospheric humidity; Atmospheric pressure; Atmospheric temperature; Breakup; Classification; Clouds; Continental shelves; Density; Fast ice; Formation; Glaciers; Growth; Heat budgets; Heat transmission; Ice leads; Ice shelves; Icebergs; Infrared remote sensing; Melting; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Pack ice; Passive microwave remote sensing; Polynyas; Salinity; SAR; Sea ice; Seasonal variations; Size; Solar radiation; Spatial distribution; Thickness; Tides; Velocity; Water masses; Water vapour; Winds

G081, G02, G15, G09
Antarctic waters; Arctic waters; Canadian Arctic waters; North Water Polynya, Baffin Bay; Ross Ice Shelf, Antarctic regions; Weddell Sea, Antarctic regions


The ocean-sea ice-atmosphere (OSA) interface in the southern Beaufort Sea   /   Barber, D.G.   Hwang, B.J.   Ehn, J.K.   Iacozza, J.   Galley, R.   Hanesiak, J.   Papakyriakou, T.   Lukovich, J.V.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 3, p. 36-67, ill., maps
References.
ASTIS record 67477.
Languages: English
Libraries: ACU

... Sea ice conditions in the CASES region fall into three distinct 'regimes': 1) offshore pack ice .... which consists of annual and multi-year sea ice in offshore regions beyond the maximum landfast ice extent; 2) landfast sea ice ... which forms annually over the continental shelves along coastal margins; and 3) the Cape Bathurst Polynya Complex ... an ice regime which is composed of a series of flaw leads and a sensible/latent heat polynya. This Cape Bathurst Polynya Complex recurs annually on average at the shelf break between Amundsen Gulf and the Beaufort Sea .... It is formally described as a recurrent polynya, in that the flaw leads which drive its formation occur each year. This recurrence happens because the central pack ice essentially acts as an 'ice bridge'; that is, a retaining structure which prevents sea ice from advecting into the region .... The resulting anticyclonic rotation of the central pack keeps ice from advecting into the flaw lead system, promoting the formation of a latent heat polynya within Amundsen Gulf. A significant interface occurs annually at the confluence of the offshore pack and the landfast ice regimes north of the Mackenzie estuary and the Tuktoyaktuk Peninsula .... Here, a highly deformed shear zone forms where the rotating offshore pack pushes against the advancing edge of landfast sea ice, resulting in compression ridges. These ridges (termed 'stamukhi' a Russian word meaning 'grounded hummock') can be quite large, exceeding several metres in the sail and keel. They act as a barrier to freshwater from the Mackenzie River during winter, thereby forming an under-ice lake named Lake Herlinveaux .... The offshore pack responds to synoptic-scale atmospheric patterns such as the Arctic Oscillation (AO) ... and the North Atlantic Oscillation (NAO) ... which, in turn, are features of the Northern Annular Mode (NAM). ... Because of its synoptic setting, the pack ice of the Beaufort Sea generally rotates in an anti-cyclonic gyre (clockwise in the northern hemisphere) centered near 78°N, 150°W. Specifically, the anti-cyclonic flow is due to a predominant surface high pressure system over the region during winter. The seasonal ice pack within the transition zone is also incorporated into the gyre during winter and rotates at about 35° per year .... The surface waters of the Canada Basin are known to originate in the Pacific ... whereas the deeper waters (>200 m) originate in the Atlantic. These deeper waters circulate in a counter-clockwise (cyclonic) flow opposite to the sea ice .... between 1978 and 1996 the annual average sea ice extent over the northern hemisphere decreased by about 34,600 km². ... Recent evidence suggests that the areal extent of sea ice is continuing to decline. ... It was quite unique to spend a year documenting mass, gas and energy fluxes across the ocean-sea ice-atmosphere interface of the CASES region. What follows are highlights of some [of] our most significant findings. ... We organize our synthesis into three sections: atmosphere..., sea ice .... and surface-energy balance .... Each section focuses on the processes which thermodynamically and dynamically control snow-covered sea ice, and the impact that the ocean and atmosphere has on these processes. ... (Au)

D, E, G, F, A
Albedo; Atmosphere; Atmospheric circulation; Atmospheric pressure; Atmospheric temperature; Breakup; Clouds; Cores; Crystals; Deformation; Density; Energy budgets; Fast ice; Formation; Growth; Ice cover; Ice leads; Mathematical models; Ocean currents; Ocean-atmosphere interaction; Optical properties; Pack ice; Physical properties; Polynyas; Rain; Remote sensing; Salinity; Satellites; Sea ice; Seasonal variations; Shear zones (Ice); Size; Snow; Solar radiation; Spatial distribution; Stamukhi; Storms; Surface properties; Temperature; Temporal variations; Thermal properties; Thermodynamics; Thickness; Velocity; Water masses; Winds

G07, G0815, G0812, G0811
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Inuvialuit Settlement Region, N.W.T./Yukon


Climate change, CASES, and a new generation of Arctic scientists = Le changement de climat, CASES et une nouvelle génération de scientifiques de l'Arctique   /   Barber, L.   Barber, D.   Fortier, M.
(Meridian = Méridien, Fall/Winter 2003, p. 13-16, 1 ill., 1 map)
Text in English and French on inverted pages.
Available online as separate English or French PDF files.
ASTIS record 60522.
Languages: English and French
Web: http://www.polarcom.gc.ca/uploads/Publications/Meridian%20Newsletter/meri_03_fall_en.pdf
Web: http://www.polarcom.gc.ca/uploads/Publications/Meridian%20Newsletter/MeridienAutomne_03.pdf
Libraries: ACU

... Schools on Board is a national initiative designed to engage schools and communities in Arctic marine science. This pilot program encourages high schools to include Arctic science in their curricula, and offers them the opportunity to apply to send a student, a teacher, or both, to participate in an Arctic field study. The program includes three components. ... Interested schools who implement an Arctic science component to their curriculum will join the Schools on Board Network. This network is a communication tool that provides them with access to resources, contacts with scientists in the field, assistance in facilitating school presentations by Canadian Arctic researchers, and information about upcoming opportunities to participate in Arctic field programs led by recognized academic and government researchers. In 2003-2004, Schools on Board will launch its first field program as part of the CASES [Canadian Arctic Shelf Exchange Study] icebreaker over-wintering. CASES has provided 12 berths on the vessel, for two one-week sessions at the end of February and mid-March, 2004. Students will be exposed to the science objectives and methods of scientific studies ranging from microbiology to climatology. Schools on Board is targeting schools that wish to expand their science program, and high school students interested in research who would like to experience Arctic marine science in the field. ... (Au)

R, E, T, D, G, J, L
Canadian Arctic Shelf Exchange Study; Climate change; Curricula; Effects of ice on climate; Environmental policy; Government; Ice cover; Icebreakers; Inuit; Marine biology; Oceanography; Polynyas; Public education campaigns; Public opinion; Research; Research personnel; Science; Sea ice; Secondary education; Teachers; Traditional knowledge

G081, G07, G0815
Beaufort Sea; Canadian Arctic; Canadian Arctic waters; Franklin Bay, N.W.T.


Arctic Climate Change Youth Forum (ACCYF) - Forum jeunesse des changements climatiques dans l'Arctique (FJCCA)   /   Barber, L.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 176
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67088.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Piloted in 2006 in conjunction with the CASES science meeting, the Schools on Board Arctic Climate Change Youth Forum has become a standing component of the program, co-hosted every two years with a high school; planned by a student organizing committee with the guidance from Schools on Board and teachers; in conjunction with an international science conference (ArcticNet/CASES/IPY-CFL). The forum focuses on: 1) the science behind Arctic climate change research, featuring keynote presentations and science sessions by leading scientists and graduate students, and 2) the role of science in policy and decision making - engaging participants in discussions and debates on environmental issues related to climate change in the Arctic. The aim of the forum is to extend outreach activities of the Schools on Board program to greater number of students and teachers, raising awareness of the science and environmental issues; and promoting science and environmental education. This presentation includes a description of this program and the 2008 experience of co-hosting the FJCCA in Quebec City in conjunction with Arctic Change 2008. (Au)

R, E, J
Climate change; Environmental impacts; Environmental policy; Research; Secondary education; Teachers; Youth

G081
Canadian Arctic


Scientific outreach : linking environmental science education in high schools with scientific research : a case study of the Schools on Board program   /   Barber, L.M.J.   Oakes, J. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2009.
xi, 212 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR53024)
ISBN 978-0-494-53024-5
Thesis (M. of Environment) - University of Manitoba, Winnipgeg, Man., 2009.
Appendices.
References.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74746.
Languages: English
Libraries: MWU

In 2003 a group of international scientists unanimously supported a scientific outreach program that would take students and teachers onboard their Arctic research expedition. Five years later 'Schools on Board' field program continues to successfully link classroom education with scientific research through authentic science experiences. This is an action research project that utilizes a systematic case study approach to document the planning process and evaluate the 2004 pilot program against a set of three criteria for quality environmental science education programs, determined from the analysis of a literature review on environmental education, science education, and scientific outreach. This project successfully answers the questions "how" and "why" did this program work in 2004? The result is a better understanding of why the program continues to work from both a practical (planning) and theoretical (pedagogical) perspective. Findings of this study include the detailed case description of the steps and key decisions made during the design, planning and implementation of this scientific outreach program, and an evaluation against the criteria identified in the study to reveal recommendations for program improvements. (Au)

R, E, D, H, T, L, J, G, I
Amundsen (Ship); ArcticNet Inc.; Climate change; Culture (Anthropology); Curricula; Design and construction; Environmental impacts; Icebreakers; Instruments; Logistics; Marine biology; Marine ecology; Native peoples; Oceanography; Public education campaigns; Research; Research personnel; Schools; Schools on Board; Science; Scientists; Sea ice; Secondary education; Teachers; Theses; Traditional knowledge; Youth

G07, G0812, G081
Amundsen Gulf, N.W.T.; Canadian Arctic; Canadian Arctic waters; Inuvik, N.W.T.; Tuktoyaktuk, N.W.T.


High-resolution paleomagnetic secular variation and relative paleointensity records from the western Canadian Arctic : implication for Holocene stratigraphy and geomagnetic field behaviour   /   Barletta, F.   St-Onge, G.   Channell, J.E.T.   Rochon, A.   Polyak, L.   Darby, D.
(Special issue : Polar Climate Stability Network / Edited by C. Hillaire-Marcel. Canadian journal of earth sciences, v. 45, no. 11, Nov. 2008, p.1265-1281, ill., map)
(GEOTOP contribution, no. 2008-0024)
References.
ASTIS record 66536.
Languages: English
Web: doi:10.1139/E08-039
Libraries: ACU

Two piston cores recovered from the Chukchi and the Beaufort seas document Arctic Holocene geomagnetic field behaviour and highlight the potential of secular variation and relative paleointensity as a regional chronostratigraphic tool. Several centennial- to millennial-scale Holocene declination and inclination features can be correlated in both cores, with other high-resolution western North American lacustrine and volcanic paleomagnetic records and with records of changes in Earth's dipole moment, supporting the geomagnetic origin of these features and implying that they are associated with changes in Earth's dipole moment. (Au)

B, D
Bathymetry; Bottom sediments; Continental shelves; Cores; Deglaciation; Geomagnetism; Magnetic properties; Measurement; Movement; North Magnetic Pole; Ocean floors; Palaeomagnetism; Radiocarbon dating; Recent epoch; Sedimentation; Spatial distribution; Stratigraphy; Temporal variations; Volcanism

G07, G0812, G0815, G04, G03
Amundsen Gulf, N.W.T.; Arctic Ocean; Canadian Beaufort Sea; Chukchi Sea; Mackenzie River, N.W.T.


Paleomagnetic dating of Holocene western Canadian Arctic sediments : combined use of secular variation and time-varying spherical harmonic model of the geomagnetic field   /   Barletta, F.   St-Onge, G.   Rochon, A.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 177
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67090.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

A major problem in Holocene paleoceanographic reconstruction from the Canadian Arctic is the difficulty to derive a robust chronology due to an often poorly constrained radiocarbon reservoir effect and the paucity of both datable material and well-dated paleoclimatic records. Here we assess the potential of using both Holocene regional paleomagnetic secular variation records and a time-varying spherical harmonic model of the geomagnetic field (CALS7K.2) to establish a preliminary age model for a marine sedimentary record recently recovered from the Beaufort Sea. Core 2004-804-650 (hereinafter referred to as core 650) was raised from the Mackenzie Shelf (Beaufort Sea) at a water depth of 246 m. The magnetic properties were studied using a 2G-Enterprises high-resolution cryogenic magnetometer in order to isolate the characteristic remnant magnetization (ChRM). In addition, the anhysteretic and the isothermal remnant magnetizations were induced in order to identify the magnetic mineralogy and grain size. The ChRM is characterized by a stable single component magnetization carried by pseudo-single domain magnetite, implying that core 650 recorded coherent paleomagnetic secular variations. A preliminary age model was constructed for the last ~6000 cal BP utilizing one AMS-14C date and four paleomagnetic tie-points derived from the comparison between core 650 ChRM declination record and the expected magnetic declination computed using the CALS7K.2 model. Based on this age model, a significant inclination low was recorded at ~2500 cal BP and is synchronous with a distinct inclination low observed in radiocarbon-dated Holocene Arctic and North American paleomagnetic secular variation records, further supporting the initial age model of core 650. Finally, the preliminary age model depicts a constant sedimentation rate of ~30 cm/ka during the last ~6000 cal BP, much lower than cores collected closer to the mouth of the Mackenzie River, thus reflecting lower sediment supplies from the Mackenzie River. (Au)

B
Bottom sediments; Cores; Geomagnetism; Identification; Instruments; Magnetic properties; Magnetite; Minerals; Radiocarbon dating; Recent epoch; Size

G07
Canadian Beaufort Sea


Dating of Holocene western Canadian Arctic sediments by matching paleomagnetic secular variation to a geomagnetic field model   /   Barletta, F.   St-Onge, G.   Channell, J.E.T.   Rochon, A.
(Quaternary science reviews, v. 29, no. 17-18, Aug. 2010, p.2315-2324, ill., maps)
(GEOTOP contribution, no. 2010-0004)
References.
ASTIS record 73517.
Languages: English
Web: doi:10.1016/j.quascirev.2010.05.035
Libraries: ACU

A recently recovered 6-m long Holocene sedimentary sequence (piston Core 2004-804-650) collected from the Beaufort Sea (western Canadian Arctic) was dated by combining the paleomagnetic secular variation (PSV) and a time-varying spherical harmonic model of the geomagnetic field (CALS7k.2). A u-channel-based paleomagnetic study reveals the presence of a stable, single component of magnetization (MAD <5°) carried by low-coercivity ferrimagnetic minerals (most likely magnetite) in the pseudo-single domain grain size range. An age-depth model spanning the last ~6000 cal BP was established from nine paleomagnetic tie points obtained by comparing the magnetic declination profiles of Core 650 and the CALS7k.2 model output. In order to verify the robustness of the method, both the magnetic inclination and the relative paleointensity (RPI) records of Core 650 were then compared with western North American lacustrine and volcanic Holocene PSV records, as well as with previously published RPI records from the Beaufort and Chukchi Seas. Several common magnetic inclination features and similar millennial-scale fluctuations are detected among the records, supporting a common geomagnetic origin of the records, and implying consistency of the derived age model. These results show the potential of using both the CALS7k.2 model output and PSV of the geomagnetic field as a practical dating tool. (Au)

B, A, D
Bathymetry; Bottom sediments; Cores; Geological time; Geomagnetism; Magnetic properties; Mass spectrometry; Mathematical models; Measurement; North Magnetic Pole; Palaeohydrology; Palaeomagnetism; Radiocarbon dating; Recent epoch; Sedimentation; Stratigraphy; X-rays

G07, G04, G0815
Canadian Arctic waters; Canadian Beaufort Sea; Chukchi Sea; Lancaster Sound, Nunavut; Mackenzie Trough, Canadian Beaufort Sea


Variations de haute fréquence du champ magnétique terrestre au cours de l'Holocène dans l'est et l'Arctique Canadien   /   Barletta, F.   St-Onge, G. [Supervisor]
Rimouski, Québec : Université du Québec à Rimouski, 2010.
xxi, 186 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR74503)
ISBN 978-0-494-74503-8
Appendices.
References.
Thesis (Ph.D.) - Université du Québec à Rimouski, Rimouski, Québec, 2010.
Front material, general introduction, and general conclusion in French; chapters 1-3 are in English. Abstract provided in both English and French.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 75100.
Languages: English or French
Web: http://semaphore.uqar.ca/410/
Libraries: QRU OONL

Several long sedimentary sequences were recovered from the Beaufort and Chukchi Seas as part of the CASES (Canadian Arctic Shelf Exchange Study) and HOTRAX (Healy-Oden Trans-Arctic Expedition) programs in 2004 and 2005, respectively as well as with the R/V Coriolis II from the St. Lawrence Estuary and Gulf in order to 1) reconstruct changes in Earth's magnetic field during the Holocene in the Western Canadian Arctic and Eastern Canada, 2) determine the strengths and the weaknesses of the recent Holocene numerical models of the geomagnetic field and 3) explore the possibility of using these models as a new dating tool for sedimentary sequences from the Canadian Arctic. Two sedimentary sequences from the Western Canadian Arctic provided changes in both direction and intensity of the geomagnetic field during the last 10 000 years. Several centennial-to millennial-scale Holocene declination and inclination features can be correlated in both cores, with other high-resolution western North American lacustrine and volcanic paleomagnetic records and with records of changes in Earth's dipole moment, supporting the geomagnetic origin of these features and implying that they are associated with changes in Earth's dipole moment. Regarding Eastern Canada, a new high-resolution Holocene paleomagnetic secular variation (PSV) and relative paleointensity (RPI) stack was constructed using u-channel paleomagnetic data from six radiocarbon-constrained marine sedimentary sequences raised along the main axis of the Laurentian Channel. Centennial-to millennial-scale declination and inclination features of the eastern Canadian stack can be correlated, within the dating uncertainties, with other Holocene North American, Icelandic and European PSV records, suggesting a common geomagnetic origin possibly hemispheric in character. Both magnetic inclination and declination data from the two analyzed geographical regions are consistent with the time-varying spherical harmonic model of the geomagnetic field CALS7k.2 (Continuous Archeomagnetic and Lake Sediment 7k years model, version 2) during the last ~7000 years. In addition, the eastern Canadian Holocene RPI stack reveals similar millennial and even centennial time-scale variations consistent with some virtual axial dipole moment (VADM) reconstructions derived from absolute paleointensity data as well as with North American lacustrine RPI records. Accordingly, these results suggest that the Holocene paleomagnetic secular variation in North America is significantly driven by large-scale (> 5000 km) geomagnetic field changes at these timescales. Nevertheless, significant discrepancies exist between the millennial-scale RPI reconstructions and the local magnetic induction field as expected from the CALS7L2 model. These differences are likely due to the heterogeneous spatial distribution of the actual paleointensity database used to constrain the CALS7L2 model, as well as with the inversion procedure used to fit the model with the background dataset. (Au)

B, A, D
Bathymetry; Bottom sediments; Cores; Geological time; Geomagnetism; Magnetic properties; Mass spectrometry; Mathematical models; Measurement; North Magnetic Pole; Palaeohydrology; Palaeomagnetism; Radiocarbon dating; Recent epoch; Sedimentation; Stratigraphy; Theses; X-rays

G07, G04
Canadian Beaufort Sea; Chukchi Sea; Mackenzie Trough, Canadian Beaufort Sea; St. Lawrence Estuary, Québec; St. Lawrence, Gulf of, Canada


Inventaire et caractérisation des tourbillons marins observés dans le golfe d'Amundsen au cours des programmes CASES et CFL   /   Barrette, J.   Gratton, Y. [Supervisor]
Québec, Québec : Université du Québec, 2012.
xviii, 126 p. : ill., maps ; 28 cm.
Thesis (M.Sc.) - Université du Québec, Québec, Québec, 2012.
Appendices.
References.
Indexed a PDF file from the Web.
ASTIS record 76833.
Languages: French
Web: http://www1.ete.inrs.ca/pub/theses/T000611.pdf
Libraries: OONL

Ce mémoire présente le résultat de l'analyse de l'ensemble des séries temporelles de profils de salinité et de température obtenues à l'intérieur du golfe d'Amundsen au cours des campagnes de terrain des programmes CASES et CFL. Les profils utilisés proviennent essentiellement du navire NGCC Amundsen présent dans la région au cours de ces périodes de même que de mouillages déployés pendant CFL à l'embouchure du golfe d'Amundsen dans le cadre de la campagne océanographique du réseau d'excellence ArcticNet. Cette analyse des profils permit en un premier temps d'atteindre le premier objectif du mémoire qui était d'identifier l'ensemble des structures cohérentes observées obtenus au cours des années 2003-2004 et 2007-2008. Ainsi, 18 structures cohérentes ayant des caractéristiques typiques du passage d'un tourbillon marin furent retenues. Le second objectif consistait à établir une classification des structures en se basant sur leurs propriétés physicochimique de manière mettre en évidence les différences et similitudes observées. Ainsi, quatre classes de structures furent établies. Par la suite, considérant les propriétés internes de chacune des classes de structures de même qu'en comparant ces observations à d'autres observations effectuées auparavant à proximité de la région d'étude, il fut alors possible d'émettre certaines hypothèses quant à l'origine de ces différentes classes de structure, ce qui correspond au troisième et dernier objectif du mémoire. Les structures de Classe 1 et 3 sont présentes à l'intérieur de la couche halocline supérieure et correspondent à des tourbillons anticycloniques. Ces structures semblent être intimement reliées au « Beaufort Shelfbreak Current » présent au-dessus du talus continental de la mer de Beaufort et qui semble se prolonger jusqu'à la région du plateau Mackenzie. Les structures de Classe 2 sont quant à elles présentes à une faible profondeur et sont caractérisées par une température interne près du point de congélation et par la présence de matière en suspension à l'intérieur. En se basant sur ces caractéristiques, il est suggéré que ces structures soient associées aux processus de convection près de la surface due à la formation de glace. Finalement, les structures de Classe 4 sont présentes à l'intérieur de la couche halocline supérieure et sont de type cyclonique. Somme tout, l'analyse des propriétés de l'ensemble des structures cohérentes observées suggère que celles-ci soient intimement reliées aux régions des plateaux continentaux. Les résultats présentés dans ce mémoire constituent une première description exhaustive de tourbillons marins à l'est de la mer de Beaufort de même qu'à l'intérieur du golfe d'Amundsen. Ce travail ouvre la porte à d'autres travaux futurs en lien à la présence de ces structures à l'intérieur du golfe d'Amundsen. Il suggère par la même occasion une étude plus approfondie de la région du talus continental du plateau Mackenzie ou semble être présent le « Beaufort Shelfbreak Current ». (Au)

D
ArcticNet Inc.; Canadian Arctic Shelf Exchange Study; Chemical oceanography; Density; Electrical properties; Fluorometry; Ocean currents; Ocean temperature; Oceanographic instruments; Oceanography; Oxygen; Research; Salinity; Temporal variations; Theses; Velocity; Water masses

G0815, G07
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Canadian Beaufort Sea


Impact of sea ice on ocean color remote sensing   /   Bélanger, S.   Ehn, J.   Babin, M.
(Remote sensing of the coastal oceanic environment / Edited by R.J. Frouin, M. Babin, S. Sathyendranath. Proceedings of SPIE, the international society for optical engineering, v.5885, 588509, Aug. 2005, 9 p., ill.)
References.
Conference held 31 July 2005 in San Diego, California.
ASTIS record 66713.
Languages: English
Web: doi:10.1117/12.616821
Libraries: AEU

We study two types of contamination of Ocean Color data related to the presence of sea ice. The first type, referred to as the adjacency effect, is the contamination of the radiance from the intended target by photons scattered in atmosphere towards the sensor but originating from a bright object such as sea ice nearby the target. The second type results from the presence of sub-pixel sea ice. In the case of the adjacency effect, the contribution of the icy environment to the top-of-atmosphere signal in the visible is not fully removed by the atmospheric correction algorithm, leading to an overestimation of the water-leaving reflectance. This is due to the strong spectral increase of atmospheric scattering with decreasing wavelength. The adjacency effect being more important at short wavelengths, the chlorophyll estimates based on the blue-to-green ratio will tend to decrease as the field of view approaches the ice edge. Conversely, contamination by sub-pixel sea ice results in an underestimation of the water-leaving reflectance, especially in the blue domain, and consequently to an overestimation of the chlorophyll concentration. The magnitude of the errors depends on the type of ice contaminating the pixel. It is more important for ice with high reflectance ratios for the wavebands 765 to 865 nm. Absolute error on the water-leaving reflectance up to 0.7% was observed, which is not acceptable for Ocean Color applications intending inversion of inherent optical properties from the absolute radiance, and for validation and vicarious calibration activities. (Au)

G, D, E, F, A
Aerosols; Albedo; Atmosphere; Atmospheric humidity; Breakup; Chlorophyll; Fast ice; Ice cover; Instruments; Light; Mathematical models; Melting; Optical properties; Ozone; Remote sensing; Satellites; Sea ice; Sea water; Seasonal variations; Snow; Snowmelt; Solar radiation; Spectroscopy; Surface properties

G0815
Amundsen Gulf, N.W.T.; Franklin Bay, N.W.T.


Photomineralization of terrigenous dissolved organic matter in Arctic coastal waters from 1979 to 2003 : interannual variability and implications of climate change   /   Bélanger, S.   Xie, H.   Krotkov, N.   Larouche, P.   Vincent, W.F.   Babin, M.
(Global biogeochemical cycles, v. 20, no. 4, GB4005, Nov. 2006, 13 p., ill., map)
References.
ASTIS record 60653.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/196.pdf
Web: doi:10.1029/2006GB002708
Libraries: ACU

Photomineralization of terrigenous dissolved organic matter (tDOM) in the Arctic Ocean is limited by persistent sea ice cover that reduces the amount of ultraviolet (UV) radiation reaching the underlying water column. UV-dependent processes are likely to accelerate as a result of shrinking sea ice extent and decreasing ice thickness caused by climatic warming over this region. In this study, we made the first quantitative estimates of photomineralization of tDOM in a coastal Arctic ecosystem under current and future sea ice regimes. We used an optical-photochemical coupled model incorporating water column optics and experimental measurements of photoproduction of dissolved inorganic carbon (DIC), the main carbon product of DOM photochemistry. Apparent quantum yields of DIC photoproduction were determined on water samples from the Mackenzie River estuary, the Mackenzie Shelf, and Amundsen Gulf. UV irradiances just below the sea surface were estimated by combining satellite backscattered and passive microwave radiance measurements with a radiative transfer model. The mean annual DIC photoproduction between 1979 and 2003 was estimated as 66.5 ± 18.5 Gg carbon in the surface waters of the southeastern Beaufort Sea, where UV absorption is dominated by chromophoric dissolved organic matter discharged by the Mackenzie River. This value is equivalent to 10% of bacterial respiration rates, 8% of new primary production rates and 2.8 ± 0.6% of the 1.3 Tg of dissolved organic carbon (DOC) discharged annually by the Mackenzie River into the area. During periods of reduced ice cover such as 1998, the latter value could rise to 5.1% of the annual riverine DOC discharge. Under an ice-free scenario, the model predicted that 150.5 Gg of DIC would be photochemically produced, mineralizing 6.2% of the DOC input from the Mackenzie River. These results show that the predicted trend of ongoing contraction of sea ice cover will greatly accelerate the photomineralization oftDOM in Arctic surface waters. (Au)

D, E, G, J, H, F
Bacteria; Carbon; Carbon cycling; Chemical oceanography; Climate change; Dissolved organic carbon; Effects of climate on ice; Environmental impacts; Geochemistry; Ice cover; Mathematical models; Measurement; Optical properties; Passive microwave remote sensing; Photosynthesis; Primary production (Biology); River discharges; Sea ice; Snow cover; Ultraviolet radiation

G0812, G0815, G03
Amundsen Gulf, N.W.T.; Canada Basin, Arctic Ocean; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.


Impacts des changements climatiques sur les flux de carbone stimulés par la lumière dans l'Océan Arctique : quantification et suivi de la photo-oxydation de la matière organique dissoute dans la Mer de Beaufort par télédétection spatiale = Response of light-related carbon fluxes in the Arctic Ocean, to climate change : quantification and monitoring of dissolved organic matter photo-oxidation in the Beaufort Sea, using satellite remote sensing   /   Bélanger, S.   Babin, M. [Supervisor]   Vincent, W.F. [Supervisor]
Paris : Université Pierre et Marie Currie, Paris, 2006.
v, xvii, 243 leaves : ill., maps ; 30 cm.
Thesis (Ph.D. - Université Pierre et Marie Currie, Paris, 2006.
Chapters I and II are in French; chapters III, IV, V, VI are in English; chapter VII (general conclusions) is in English and French.
Appendices.
References.
General bibliography: p. 211-230.
ASTIS record 60653 describes chapter 3 of this thesis, published separately.
ASTIS record 75148.
Languages: English or French

Photochemical oxidation of the CDOM and the resulting production of CO2 is now known to be a significant process in the cycling of carbon in the ocean-atmosphere system. One environment where that process may take a major role in the context of climate change is the Arctic Ocean because of: 1) the increasing amount of terrestrial CDOM released by the melting permafrost and brought to coastal ocean by rivers, 2) the decreasing summer ice cover that allows more solar radiation to penetrate the water column, and 3) the continuing increase in UV radiation over that region. A coupled optical-photochemical model was used to assess the role of photo-oxidation in the carbon cycle of the Arctic Ocean. To calculate the photoproduction of CO2 (PDIC), the incoming spectral irradiance, including UVs, is modeled with a radiative transfer model using as input satellite observations of sea ice, ozone, aerosols and cloud cover covering the 1979 to 2004 period, in situ determinations of the apparent quantum yield for the photoproduction of CO2 made in the Beaufort Sea are used for the calculations. The contribution of CDOM to the total absorption coefficient, which is a parameter of the model, could be derived either from in situ measurements or from Ocean Color imagery using a new empirical algorithm. Unlike most semi-analytical approaches currently proposed in the literature, the proposed empirical algorithm provides a means to separate the CDOM from the non-algal particles absorption coefficients at the regional scale. The use of Ocean Color remote sensing at high latitude is, however, compromised by the presence of sea ice that contaminates the data. This particular problem was addressed in this study, and a method was proposed to detect and eliminate the contaminated pixel. Finally, it is shown that the level of PDIC is similar to the level of sequestered rates of organic carbon in the ocean sediments, which was produced through marine photosynthesis; and that the increase in UV and decrease in summer sea ice over the last 26 years have led to an increase in PDIC by about 15%. These results suggest that the predicted trend of ongoing contraction of sea ice cover will greatly accelerate the photomineralization of CDOM in Arctic surface waters. (Au)

E, D, H, J, G
Aerosols; Albedo; Bacteria; Carbon cycling; Chemical oceanography; Chlorophyll; Climate change; Clouds; Colored dissolved organic matter; Effects monitoring; Environmental impacts; Geochemistry; Infrared remote sensing; Light; Mathematical models; Ocean currents; Ocean-atmosphere interaction; Ozone; Permafrost; Photosynthesis; Primary production (Biology); River discharges; Satellites; Sea ice; Solar radiation; Surface properties; Suspended solids; Temporal variations; Theses; Ultraviolet radiation

G07, G03, G0815
Amundsen Gulf region, N.W.T.; Arctic Ocean; Banks Island waters, N.W.T.; Canada Basin, Arctic Ocean; Canadian Beaufort Sea; Mackenzie Estuary, N.W.T./Yukon


Impact of sea ice on the retrieval of water-leaving reflectance, chlorophyll a concentration and inherent optical properties from satellite ocean color data   /   Bélanger, S.   Ehn, J.K.   Babin, M.
(Remote sensing of environment, v.111, no. 1, 15 Nov. 2007, p. 51-68, ill., maps)
Appendices.
References.
ASTIS record 63298.
Languages: English
Web: doi:10.1016/j.rse.2007.03.013
Libraries: ACU

Two physical phenomena by which satellite remotely sensed ocean color data are contaminated by sea ice at high latitudes are described through simulations and observations: (1) the adjacency effect that occurs along sea ice margins and (2) the sub-pixel contamination by a small amount of sea ice within an ocean pixel. The signal at the top of the atmosphere (TOA) was simulated using the 6S radiative transfer code that allows modeling of the adjacency effect for various types of sea ice surrounding an open water area. In situ sea ice reflectance spectra used in the simulations were measured prior to and during the melt period as part of the 2004 Canadian Arctic Shelf Exchange Study (CASES). For sub-pixel contamination, the TOA signal was simulated for various surface reflectances obtained by linear mixture of both sea ice and water-leaving reflectances (rho w). The standard atmospheric correction algorithm was then applied to the simulated TOA spectra to retrieve rho w spectra from which chlorophyll a concentrations (CHL) and inherent optical properties (IOPs) were derived. The adjacency effect was associated with large errors (>0.002) in the retrieval of rho w as far as 24 km from an ice edge in the blue part of the spectrum (443 nm). Therefore, for moderate to high CHL (>0.5 mg/m³), any pixels located within a distance of 10-20 km from the ice edge were unreliable. It was also found necessary to consider the adjacency effect when the total absorption coefficient (at) was to be retrieved using a semi-analytical algorithm. at(443) was underestimated by more than 35% at a distance of 20 km from an ice edge for CHL >0.5 mg/m³. The effect on the retrieval of the particle backscattering coefficient (bbp) was important only for clear waters (CHL ~0.05 mg/m³). In contrast, sub-pixel contamination by a small amount of sea ice produced systematic underestimation of rho w in the blue because of incorrect interpretation of enhanced reflectance in the near infrared that is attributed to higher concentrations of atmospheric aerosols. In general, sub-pixel contamination was found to result in overestimations of CHL and at, and underestimations of bbp. A simple method was proposed to flag pixels contaminated by adjacency effect. (Au)

G, E, J, H, A, D
Aerosols; Biological productivity; Biomass; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chlorophyll; Climate change; Effects monitoring; Environmental impacts; Fast ice; Ice floes; Mathematical models; Melting; Optical properties; Photosynthesis; Phytoplankton; Polynyas; Primary production (Biology); Remote sensing; Sea ice; Sea water; Seasonal variations; Snow cover; Surface properties; Suspended solids; Temporal variations

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


An empirical ocean color algorithm for estimating the contribution of chromophoric dissolved organic matter to total light absorption in optically complex waters   /   Bélanger, S.   Babin, M.   Larouche, P.
(Journal of geophysical research, v.113, no. C4, C04027, Apr. 2008, 14 p., ill., maps)
Appendix.
References.
ASTIS record 65872.
Languages: English
Web: doi:10.1029/2007JC004436
Libraries: ACU

To estimate the depth-integrated rate of photochemical processes involving chromophoric dissolved organic matter (CDOM) in coastal waters, the contribution of CDOM to the total absorption coefficient must be known from UV to green. At 307 sites sampled in various coastal marine environments, the ratio between CDOM and the total absorption coefficient ([a(CDOM)/a(t)]) at 412 nm was found to vary over a wide range, from 0.20 to 0.95. An empirical algorithm was developed to retrieve [a(CDOM)/a(t)](412) from satellite remote sensing reflectance. The absolute uncertainty on the [a(CDOM)/a(t)] retrieval was 0.14. As exemplified with the data from the Baltic and North Seas, the algorithm provides a means to distinguish the contribution of CDOM to the absorption coefficient of colored detrital material (i.e., CDM = CDOM + nonalgal particles) at the regional scale. The implications of the variability in the magnitude and spectral shape of [a(CDOM)/a(t)] for the assessment of depth-integrated production of any photoproducts involving CDOM photolysis are discussed in details. We applied the algorithm to a Sea-viewing Wide Field-of-View Sensor (SeaWiFS) image of the Southeastern Beaufort Sea where terrestrial inputs are abundant. The spatial variability in the [a(CDOM)/a(t)] reaches as much as threefold over the continental shelf and beyond. These results clearly show that it is necessary to account for the spatial variability of [a(CDOM)/a(t)] when quantifying CDOM-related photochemical processes in the ocean. (Au)

D, H, A
Carbon; Chemical oceanography; Colored dissolved organic matter; Light; Mathematical models; Optical properties; Phytoplankton; Satellite photography; Sea water; Spatial distribution; Spectroscopy; Suspended solids; Ultraviolet radiation

G07, G0815
Amundsen Gulf, N.W.T.; Baltic Sea; Canadian Beaufort Sea; English Channel; Mediterranean Sea; North Sea


A novel chemical fossil of palaeo sea ice : IP25   /   Belt, S.T.   Massé, G.   Rowland, S.J.   Poulin, M.   Michel, C.   LeBlanc, B.
(Organic geochemistry, v. 38, no. 1, Jan. 2007, p. 16-27, ill., 1 map)
References.
ASTIS record 60820.
Languages: English
Web: doi:10.1016/j.orggeochem.2006.09.013
Libraries: ACU

A unique and novel organic compound has been detected in sea ice samples from three locations in the Canadian Arctic, thousands of kilometers apart. It is likely that this biomarker is produced by diatoms living in the sea ice and we provide evidence which suggests that the compound, a C25 monounsaturated hydrocarbon (IP25), may be a specific, sensitive and stable proxy for sea ice in sediments over at least the Holocene. Since it has not been reported before, we confirmed its identity by synthesis and used the synthesized compound as a reference for quantifying IP25 in a range of sediments from an East-West transect in the Canadian Arctic. The recent sediments are either seasonally covered with ice or have permanent ice cover. Older sediments containing IP25 have been dated using radiocarbon methods to at least 9000 yr. If the concept proves generally applicable, monitoring IP25 in further sediment cores along with other accepted proxies, should allow movements in the position of the ice edge throughout the Holocene (at least) to be better determined, which is essential for accurate calibration of climate prediction models. A similar approach for Antarctic samples of ice and sediments would also seem worthwhile. (Au)

G, H, J, B
Biological sampling; Bottom sediments; Chromatography; Cores; Coring; Diatoms; Foraminifera; Hydrocarbons; Ice cover; Identification; Lipids; Logistics; Mass spectrometry; Measurement; Microscopes; Nuclear magnetic resonance; Phytoplankton; Plant distribution; Plant ecology; Radiocarbon dating; Recent epoch; Sea ice; Sea ice ecology; Seasonal variations; Spatial distribution; Spectroscopy; Temporal variations

G0815, G0814, G09, G03, G07
Amundsen Gulf, N.W.T.; Barrow Strait, Nunavut; Button Bay, Nunavut; Canadian Beaufort Sea; Dease Strait, Nunavut; Ellesmere Island waters, Nunavut; Franklin Bay, N.W.T.; Lancaster Sound, Nunavut; McDougall Sound, Nunavut; North Water Polynya, Baffin Bay; Pond Inlet, Nunavut; Victoria Strait, Nunavut


Distinctive 13C isotopic signature distinguishes a novel sea ice biomarker in Arctic sediments and sediment traps   /   Belt, S.T.   Massé, G.   Vare, L.L.   Rowland, S.J.   Poulin, M.   Sicre, M.-A.   Sampei, M.   Fortier, L.
(Marine chemistry, v.112, no. 3-4, Dec. 2008, p. 158-167, ill., maps)
References.
ASTIS record 74208.
Languages: English
Web: doi:10.1016/j.marchem.2008.09.002
Libraries: ACU

A C25 highly branched isoprenoid (HBI) monoene hydrocarbon, designated IP25, has been proposed previously to originate from diatoms living in Arctic sea ice, while the presence of IP25 in sediments has been suggested to be a proxy for the occurrence of former Arctic sea ice. Here, we show that the 13C isotopic composition of IP25 in sea ice, in sediment trap material collected under sea ice, and in high latitude northern sediments, is distinctive (isotopically 'heavy') and distinguishable from that of organic matter of planktonic or terrigenous origin. Mean delta 13C values for IP25 were -22.3 ±0.4‰ (sea ice), -19.6 ±1.1‰ (sediment traps) and -19.3 ±2.3‰ (sediments). These measurements, therefore, support further the proposed use of IP25 as an Arctic sea ice proxy. (Au)

G, D, H, B
Carbon; Cores; Diatoms; Hydrocarbons; Identification; Isotopes; Lipids; Phytoplankton; Sea ice; Sedimentation; Sediments (Geology); Suspended solids

G0815, G09
Barrow Strait, Nunavut; Dease Strait, Nunavut; Franklin Bay, N.W.T.; Lancaster Sound, Nunavut; North Water Polynya, Baffin Bay; Victoria Strait, Nunavut


Variations of the abundance and nucleic acid content of heterotrophic bacteria in Beaufort Shelf waters during winter and spring   /   Belzile, C.   Brugel, S.   Nozais, C.   Gratton, Y.   Demers, S.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 946-956, ill.)
References.
ASTIS record 65247.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.12.010
Libraries: ACU

Depth profiles of heterotrophic bacteria abundance were measured weekly over a 6-month period from December to May in Franklin Bay, a 230 m-deep coastal Arctic Ocean site of the southeastern Beaufort Sea. Total bacteria, low nucleic acid (LNA) and high nucleic acid (HNA) bacteria abundances were measured using flow cytometry after SYBR Green I staining. The HNA bacteria abundance in surface waters started to increase 5-6 weeks after phytoplankton growth resumed in spring, increasing from 1×10**5 to 3×10**5 cells/mL over an 8-week period, with a net growth rate of 0.018/d. LNA bacteria response was delayed by more than two months relative to the beginning of the phytoplankton biomass accumulation and had a lower net growth rate of 0.013/d. The marked increase in bacterial abundance occurred before any significant increase in organic matter input from river discharge (as indicated by the unchanged surface water salinity and DOC concentrations), and in the absence of water temperature increase. The abundance of bacteria below the halocline was relatively high until January (up to 5×10**5 cells/mL) but then decreased to values close to 2×10**5 cells/mL. The three-fold bacterial abundance increase observed in surface waters in spring was mostly due to HNA bacteria, supporting the idea that these cells are the most active. (Au)

H, I, J, D
Algae; Animal distribution; Animal growth; Animal population; Biological productivity; Biological sampling; Biomass; Chlorophyll; Dissolved organic carbon; Fluorometry; Heterotrophic bacteria; Identification; Ocean temperature; Phytoplankton; Plant growth; Salinity; Sea water; Seasonal variations; Water masses

G0815
Franklin Bay, N.W.T.


Variability of chlorophyll-a from ocean color images in the Beaufort Sea   /   Ben Mustapha, S.   Larouche, P.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 180
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67095.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Satellite remote sensing offers a powerful tool for regional and global scale monitoring of the spatial distribution of key environmental parameters. This is particularly true for the study of the arctic marine ecosystem that is highly undersampled. In the framework of the Canadian Arctic Shelf Exchanges Study (CASES) and the Arcticnet programs we investigated seasonal and interannual variability of chlorophyll in the Beaufort Sea in order to better understand the biological processes occurring and to evaluate the variability of environmental conditions and physical forcing affecting phytoplankton. Multiple remote sensing data sources were used in the study. SeaWiFS and MODIS weekly and monthly composites from 1998 to 2008 were used to measure the phytoplankton biomass, AVHRR-derived sea surface temperatures were used to detect oceanographic features and SSMI data were used to measure the ice cover. Using a set of in situ measurements gathered during CASES (2004) and the ArcticNet (2005, 2006, 2007) field programs, we first conducted an evaluation of the current ocean color operational algorithms as the region is strongly influenced by dissolved organic matter coming from the Mackenzie river. We were able to show that these algorithms overestimate the actual in situ biomass by roughly a factor of four. To solve that problem, we built our own algorithm using optical data measured during CASES-2004. Results show that we are now able to estimate phytoplankton biomass in the Amundsen Gulf region with a much better precision. However, given the strong influence of the Mackenzie River outflow on the optical properties along the Beaufort Sea coast, we selected to eliminate these areas based on the R490/R669 reflectance ratio that is highly correlated to salinity. After this screening was done, time series were built for five sub-areas (Cape Bathurst, Franklin Bay, Amundsen Gulf, Sachs harbour coast and offshore Beaufort). These areas were selected to correspond to locations where long term oceanographic moorings are deployed. Because of the ice cover and the high latitude, phytoplankton in these areas can be observed by ocean color satellite only from April to September. Results show that monthly mean chlorophyll concentration for all sub-areas has a high interannual variability in the timing, importance and duration of blooms. The seasonal trend shows that chlorophyll-a normally reaches a maximum value between May and July but fall blooms are also seen at some occasions. Spatially, Sachs harbour and Amundsen Gulf are the only regions having similar trends showing regional scale variability. Future work will try to explain how the phytoplankton distribution is influenced by various environmental parameters and physical processes. (Au)

H, D, G, F
Biomass; Chlorophyll; Dissolved organic carbon; Infrared remote sensing; Ocean temperature; Optical properties; Phytoplankton; Plant distribution; Rivers; Salinity; Satellites; Sea ice; Seasonal variations; Sediment transport; Special Sensor Microwave/Imager ; Spectroscopy; Suspended solids; Temporal variations; Thickness

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Sachs Harbour, N.W.T.


Evaluation of ocean color algorithm and spatial scales of variability using MODIS and SeaWIFS data in the Canadian Arctic waters : the Beaufort Sea   /   Ben Mustapha, S.   Larouche, P.
In: IGARSS Boston 2008 : 2008 IEEE International Geoscience & Remote Sensing Symposium, July 6-11, 2008, Boston, Mass. - Piscataway, N.J. : Institute of Electrical and Electronics Engineers, 2008, [2] p.
Abstract of a poster presentation (#3666).
Indexed a PDF file from the Web.
ASTIS record 74214.
Languages: English
Web: http://www.igarss08.org/Abstracts/pdfs/3666.pdf

As part of the Canadian Arctic Shelf Exchanges Study (CASES) and the Arcticnet field program conducted respectively in 2003, 2004 and 2005, we collected an extensive in situ optical and biological data set covering the entire Canadian Beaufort sea shelf and including the productive Cape Bathurst polynya. The data measured indicated that neither the OC4v4 nor the OC3M algorithm currently used for processing SeaWiFS and AQUAMODIS data are appropriate for the measurement of chlorophyll a concentration in the Cape Bathurst polynya. Algorithms developed specifically for the Arctic do not offer better performances. Previous studies conducted in arctic waters showed that operational algorithms were not performing well generally overestimating chlorophyll concentrations due to the presence of dissolved and suspended matter and because of significant pigment packaging in the arctic phytoplankton species. According to these results, it appears that the general description of phytoplankton biomass concentration and phytoplankton production available from the Arrigo and van Dijken (2004) study are probably seriously biased towards higher values. When divided by the MNB value for the OC4L algorithm (3.64), the maximum daily phytoplankton production estimated using SeaWiFS data is now the lowest of all major Arctic polynyas such as NEW and NOW. The Beaufort sea, at least in its coastal domain, is dominated by the freshwater outflow from the Mackenzie. The Mackenzie plume behaviour is known to be highly variable depending on the runoff intensity and physical forcing by the coastal circulation and the wind field leading to a strong spatial variability showing frontal regions, salinity fingers and other features. The in situ data were thus used to develop a locally tuned MODIS algorithm allowing a better estimation of the chlorophyll concentration for these case II waters. Time series of images processed using this improved algorithm give us the opportunity to study the relationships between the phytoplankton distribution and the physical environment. We believe that the spatial and temporal patterns described in this study are still valid despite the problem with the evaluation of the intensity of the phytoplankton bloom in the cap Bathurst. To evaluate the spatial scales of variability, a semi-variogram analysis was applied. The scales of variability for chlorophyll appear affected by the presence of dissolved matter and shows structures at about 70 km. More work will be needed to extend the study to other regions and time and to study the finer scales of variability that should be present in the data set. (Au)

H, D, A, F
Biomass; Chlorophyll; Electronic data processing; Ocean currents; Oceanography; Optical properties; Phytoplankton; Plant distribution; Polynyas; Primary production (Biology); Quality assurance; River discharges; Runoff; Salinity; Satellite photography; Spatial distribution; Suspended solids; Temporal variations

G07, G0815
Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea


Ocean color algorithms in the Amundsen Gulf : new parameterization using SeaWiFS, MODIS and MERIS spectral bands   /   Ben Mustapha, S.   Larouche, P.   Bélanger, S.   Tang, S.   Michel, C.
In: ArcticNet programme 2009 : annual scientific meeting, 8-11/12/2009, Victoria, B.C. = ArcticNet programme 2009 : réunion scientifique annuelle, 8-11/12/2009, Victoria, B.C. - [Québec, Québec] : ArcticNet, 2009, p. 78-79
Abstract of a poster presentation.
Indexed a PDF file from the Web.
ASTIS record 73186.
Languages: English
Web: http://www.arcticnetmeetings.ca/docs/asm2009_programme_long.pdf
Libraries: ACU

Arctic polynyas are regions where enhanced biological activity exists due to a favorable physical environment. The Cape Bathurst polynya located in the Amundsen Gulf is the third largest Arctic polynya. Previous studies conducted using remote sensing indicated that this polynya had a high level of primary productivity that did not match well with in situ data possibly indicating a problem with the chlorophyll a retrieval algorithm. As part of the Canadian Arctic Shelf Exchanges Study (CASES), an in situ optical and biological data set was collected in the Amundsen Gulf region, extending onto the Mackenzie shelf area. This region is under the influence of the nearby Mackenzie River, with its freshwater plume influencing the optical properties of the region. The data set was used for in situ validation of six algorithms using SeaWiFS, MODIS and MERIS spectral bands and for developing new ones. Results show that all these algorithms fail to correctly evaluate the low levels of chlorophyll-a concentration in the Amundsen Gulf region. The standard chlorophyll retrieval algorithms for SeaWiFS (OC4v4), MODIS (OC3M) and MERIS (OC4Me), overestimated in situ chlorophyll-a by roughly a factor of four. The northern latitudes version of the SeaWiFS algorithm (Arc00 OC4P and OC4L arctic) provided slightly better results but were still highly inaccurate (RMS=214% and 154%). The semi-analytical algorithm GSM01 gave better results (RMS=115%). Locally tuned empirical algorithms, allowing a better estimation of the low chlorophyll-a concentrations for that region: Bathurst_MODIS (RMS=42%), Bathurst_SeawiFS (RMS=46%) and Bathurst_MERIS (RMS=61.9%). Application of SeaWiFS and MODIS new algorithms to satellite data showed a better estimation of remote sensing reflectance using the Bathurst_MODIS algorithm. Both algorithms show very large chlorophyll concentrations overestimations confirming the results obtained with the in situ optical measurements. The overestimation appears relatively insensitive to the atmospheric correction scheme used. Inherent optical properties (aph, aCDOM and aNAP) were also measured at the 24 stations used to validate the algorithms. When compared to values from other coastal regions, the arctic is clearly dominated by CDOM with aph and aNAP representing at most 30% of the absorption capacity in the blue region of the spectra thus explaining the poor performance of the SeaWiFS and MODIS operational algorithms. This is the first step towards the development of more general semi-analytical bio-optical models with parameterization adapted to arctic waters. (Au)

H, D, A
Chlorophyll; Colored dissolved organic matter; Electronic data processing; Oceanography; Optical properties; Polynyas; Satellite photography

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Evaluation of ocean color algorithms in the southeastern Beaufort Sea, Canadian Arctic : new parameterization using SeaWiFS, MODIS and MERIS spectral bands   /   Ben Mustapha, S.   Bélanger, S.   Larouche, P.
(Canadian journal of remote sensing, v. 38, no. 5, Oct. 2012, p. 535-556, ill., map)
References.
Appendix.
French abstract provided.
ASTIS record 77174.
Languages: English
Web: doi:10.5589/m12-045
Libraries: ACU

With the increasing interest for Arctic Ocean resources and faced with its sensitivity to climate change, it is important to accurately monitor the chlorophyll-a (Chla) concentration that is a key indicator of phytoplankton biomass and marine productivity. The performances of three operational algorithms (OC4v6, OC3Mv6, OC4Mev6), two Arctic adapted algorithms (OC4L, OC4P), and one semi-analytical (GSM01) algorithm to estimate Chla were evaluated using in situ measurements collected in the southeastern Beaufort Sea. All evaluated algorithms clearly overestimated Chla by a factor of three to five. A high contribution of colored dissolved organic matter and nonalgal particles to the blue light absorption appeared as the source of that poor performance. It was also found that fluorometrically measured Chla were two times greater than those determined from high-performance liquid chromatography, contributing to the observed discrepancies between our findings and previous studies carried out in the Arctic. We propose regionally adapted and new algorithms allowing accurate estimation of Chla in the southeastern Beaufort Sea. Finally, a matchup analysis of coincident in situ data and satellite overpass showed that the normalized water-leaving reflectance and the blue-to-green ratio retrieval were more accurate for SeaWiFS than for MODIS and MERIS. (Au)

H, D, A, G
Biological productivity; Biomass; Chlorophyll; Chromatography; Colored dissolved organic matter; Fluorometry; Mathematical models; Nitrogen; Ocean currents; Oceanography; Optical properties; Phytoplankton; Polynyas; Satellite photography; Sea ice; Sea water; Water masses

G0815, G07
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Mackenzie River, N.W.T.


Étude de la variabilité spatio-temporelle des processus physiques et biologiques dans la mer de Beaufort par télédétection et dans un contexte de changements climatiques dans l'océan Arctique   /   Ben Mustapha, S.   Dubois, J. [Supervisor]   Larouche, P. [Supervisor]
Sherbrooke, Québec : Université de Sherbrooke, 2014.
xxi, 238 p. : ill., maps ; 28 cm.
Thesis (Ph.D.).
References.
ASTIS record 81665.
Languages: French
Web: http://savoirs.usherbrooke.ca/handle/11143/5364
Web: http://www.collectionscanada.gc.ca/obj/thesescanada/vol2/QSHERU/TC-QSHERU-11143_5364.pdf
Web: http://savoirs.usherbrooke.ca/bitstream/11143/5364/1/Ben_Mustapha_Selima_PhD_2014.pdf
Libraries: OONL

The Arctic Ocean ecosystem is experiencing significant changes such as a drastic reduction in seasonal sea-ice cover linked to global warming. These changes are likely to modify the physics, biogeochemistry and ecology of this unique environment in ways that are yet to be understood. In this context, we processed satellite data and in situ measurements in the southeastern Beaufort Sea to explore the spatial and temporal variability of phytoplankton biomass and link it to existing physical processes in this region. The optical properties of the Beaufort Sea being under the influence of the Mackenzie River plume, it was likely that operational ocean color algorithms did not allow an accurate estimate of chlorophyll-a concentration (Chl-a) that is a key indicator of phytoplankton biomass and marine productivity. Analysis of bio-optical data confirmed this hypothesis showing an overestimation of Chl-a in situ by a factor of three to five. High contribution of colored dissolved organic matter and non algal particles to the blue light absorption appears as the source of that poor performance. We propose regionally adapted and new algorithms using ratio of two spectral bands allowing better accuracy estimation of Chl-a in the southeastern Beaufort Sea. A match-up analysis of coincident in situ data and satellite overpass showed that the normalized water-leaving reflectance and the blue-to-green ratio retrieval were more accurate for SeaWiFS data than for MODIS and MERIS data. We investigated temporal and spatial linkages between physical and biological parameters to infer the boundaries of biophysical areas in the Canadian Beaufort Sea. Monthly sea surface temperature (AVHRR) data and chlorophyll a data from SeaWiFS were collected over seven years in five geographical sub-regions in the Beaufort Sea (1998-2004). Results showed that the spatial, temporal and inter-annual variability of phytoplankton biomass are driven by several environmental factors affecting the stratification of the water column: wind forcing, ice dynamics, air temperature, irradiance and currents. A cluster analysis based on the concept of non-static provinces was used to define four biophysical provinces in this sea. Positive temporal trends were detected for Chl-a over two regions of the Beaufort Sea: the Mackenzie Shelf and the southern portion of Amundsen Gulf. Finally, an analysis of spatial gradients, using 11 years of sea surface temperature images, allowed the detection of recurrent thermal fronts. These spatial structures play a major role in the marine ecosystem, particularly because of their impact on the development of phytoplankton biomass. We highlighted new frontal structures on the Mackenzie Shelf and in the Cape Bathurst polynya area. These identified new fronts are mainly related to bathymetric features of the region, the presence of the Mackenzie River plume and the Beaufort Gyre. In conclusion, this study has generated new information on the interactions between physical and biological processes to better understand the biogeochemical and ecological consequences of climate change in the Beaufort Sea. (Au)

D, E, H, J, G
Algae; Atmospheric temperature; Biomass; Chlorophyll; Climate change; Colored dissolved organic matter; Geochemistry; Ice cover; Marine ecology; Mathematical models; Ocean currents; Optical properties; Phytoplankton; Remote sensing; River discharges; Satellite photography; Sea ice; Spatial distribution; Surface temperature; Temporal variations; Theses; Water masses; Winds

G07, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Mackenzie River, N.W.T.


Spatial and temporal variability of sea-surface temperature fronts in the coastal Beaufort Sea   /   Ben Mustapha, S.   Larouche, P.   Dubois, J.-M.M.
(Continental shelf research, v.124, 1 August 2016, p. 134-141, ill., maps)
References.
ASTIS record 82101.
Languages: English
Web: doi:10.1016/j.csr.2016.06.001
Libraries: ACU

An analysis of 11 years of sea surface temperatures images allowed the determination of the frontal occurrence probability in the southeastern Beaufort Sea using the single-image edge detection method. Results showed that, as the season progresses, fronts become more detectable due to solar heating of the surface layer. Some recurrent features can be identified in the summer time frontal climatology such as the Mackenzie River plume front, the Cape Bathurst front, the Mackenzie Trough front and the Amundsen Gulf front. These areas may be playing an important role in the biological processes acting as drivers to local enhanced biological productivity. (Au)

D, G, E, J
Albedo; Biological productivity; Ice cover; Maps; Marine ecology; Ocean temperature; Particulate organic matter; Satellite photography; Seasonal variations; Spatial distribution; Stream flow; Surface temperature; Temporal variations; Water masses; Winds

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Hydroacoustic detection of large winter aggregations of arctic cod (Boreogadus saida) at depth in ice-covered Franklin Bay (Beaufort Sea)   /   Benoit, D.   Simard, Y.   Fortier, L.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C6, C06S90, June 2008, 9 p., ill., map)
References.
ASTIS record 64587.
Languages: English
Web: doi:10.1029/2007JC004276
Libraries: ACU

In the Canadian Arctic, the large biomass of Arctic cod that must exist to explain consumption by predators has eluded detection. From December 2003 to May 2004, acoustic estimates of Arctic cod biomass at a 225-m-deep station in central Franklin Bay (southeastern Beaufort Sea) increased progressively by 2 orders of magnitude, reaching maximum values of 2.7 and 55 kg/m² in April. During accumulation in Franklin Bay, the fish occupied the lower part of the Pacific halocline (140 m to bottom), where the temperature-salinity signature (-1.4 to 0.3°C; 33 to 34.8 practical salinity units) corresponded to slope waters. Currents at 200 m along the western slope of Amundsen Gulf headed SSE in early winter, suggesting the passive advection of Arctic cod from Amundsen Gulf into Franklin Bay. Retention in Franklin Bay against the general circulation resulted from the fish keeping at depth to reduce predation by diving seals and/or to benefit from relatively warm temperatures in the lower halocline. Extrapolating a standing biomass of 11.23 kg/m² at the station in April to the whole of Franklin Bay, the availability of polar cod would amply satisfy the requirements of predators. Dense accumulations of Arctic cod in embayments in winter likely play an important role in structuring the ecosystem of the Beaufort Sea. Understanding how climate change and the reduction of the sea ice cover will affect the stability of the oceanographic/behavioral accumulation process requires further research and modeling. (Au)

I, D, J
Animal behaviour; Animal distribution; Animal ecology; Animal food; Animal migration; Animal population; Arctic cod; Biological sampling; Biomass; Chlorophyll; Copepoda; Detection; Fast ice; Marine ecology; Ocean currents; Ocean temperature; Predation; Salinity; Seals (Animals); Sonar; Velocity; Water masses; Wildlife habitat; Zooplankton

G0815, G07
Amundsen Gulf, N.W.T.; Beaufort Sea; Franklin Bay, N.W.T.


Seasonal and daily scale behaviour of arctic cod winter aggregations under the sea-ice cover at a fixed station in Franklin Bay (Beaufort Sea)   /   Benoit, D.   Simard, Y.   Fortier, L.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 49
Abstract of a Topical Session presentation.
Indexed a PDF file from the Web.
ASTIS record 66813.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

In the Canadian Arctic, the large biomass of Arctic cod that must exist to explain consumption by predators has eluded detection. From December 2003 to May 2004, acoustic estimates of Arctic cod biomass at a 225-m deep station in central Franklin Bay (southeastern Beaufort Sea) increased progressively by two orders of magnitude, reaching maximum values of 2.7 kg/m³ and 55 kg/m² in April. During accumulation in Franklin Bay, the fish occupied the lower part of the Pacific Halocline (140 m to bottom), where the temperature-salinity signature (-1.4 °C to 0.3 °C; 33 to 34.8 PSU) corresponded to slope waters. Currents at 200 m along the western slope of Amundsen Gulf headed SSW throughout winter, suggesting the passive advection of cod from southeastern Beaufort Sea into Franklin Bay. Retention in Franklin Bay against the general circulation resulted from the fish keeping at depth to reduce predation by diving seals and/or to benefit from relatively warm temperatures in the lower halocline. The mean Arctic cod standing biomass estimated (11.23 kg/m²) would amply satisfy the requirements of predators. Furthermore, Arctic cod diel vertical migrations (DVM) were observed under the sea-ice cover, until the day/night alternation was occurring (i.e. end of April). During the dark hours, a small part of the population migrated up to 80 m, while most of the fish remained below 140 m. DVM were triggered by light and tracked the lengthening of the photoperiod. Vertical distribution of Arctic cod's main preys matched the night distribution of the fish, suggesting that they migrated to feed, while minimizing the risk of predation by seals. DVM stopped in May, at the beginning of the 24 h light period, and most of Arctic cod were distributed between 50 and 150m. This dramatic change in their distribution and behaviour suggest a seasonal switch of fish activity, triggered by light. Analysis of this very dense Arctic cod aggregation, at a seasonal and daily scale, enabled to enlighten the interactions of Arctic cod with its preys and predators, in its deep, ice-covered, and low-light winter environment. Understanding the under-ice ecology of Arctic cod is a gateway to envisage how the decrease of the sea-ice cover may affect this key-species of the Arctic pelagic ecosystem. (Au)

I, D, G, J
Animal behaviour; Animal distribution; Animal food; Arctic cod; Biomass; Diurnal variations; Light; Ocean currents; Ocean temperature; Photoperiodism; Predation; Salinity; Sea ice ecology; Seals (Animals); Seasonal variations; Sonar; Winter ecology

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


From polar night to midnight sun : photoperiod, seal predation, and the diel vertical migrations of polar cod (Boreogadus saida) under landfast ice in the Arctic Ocean   /   Benoit, D.   Simard, Y.   Gagné, J.   Geoffroy, M.   Fortier, L.
(Polar biology, v. 33, no. 11, Nov. 2010, p.1501-1520, ill., map)
References.
ASTIS record 71864.
Languages: English
Web: doi:10.1007/s00300-010-0840-x
Libraries: ACU

The winter/spring vertical distributions of polar cod, copepods, and ringed seal were monitored at a 230-m station in ice-covered Franklin Bay. In daytime, polar cod of all sizes (7–95 g) formed a dense aggregation in the deep inverse thermocline (160–230 m, -1.0 to 0°C). From December (polar night) to April (18-h daylight), small polar cod <25 g migrated into the isothermal cold intermediate layer (90–150 m, -1.4°C) at night to avoid visual predation by shallow-diving immature seals. By contrast, large polar cod (25–95 g), with large livers, remained below 180 m at all times, presumably to minimize predation by deep-diving mature seals. The diel vertical migration (DVM) of small polar cod was precisely synchronized with the light/dark cycle and its duration tracked the seasonal lengthening of the photoperiod. The DVM stopped in May coincident with the midnight sun and increased schooling and feeding. We propose that foraging interference and a limited prey supply in the deep aggregation drove the upward re-distribution of small polar cod at night. The bioluminescent copepod Metridia longa could have provided the light needed by polar cod to feed on copepods in the deep aphotic layers. (Au)

I, D, G, J
Animal behaviour; Animal distribution; Animal food; Animal population; Arctic cod; Biological sampling; Biomass; Copepoda; Diurnal variations; Diving (Animals); Fast ice; Food chain; Internal organs; Light; Measurement; Ocean currents; Ocean temperature; Parasites; Photoperiodism; Predation; Salinity; Sea ice; Sea ice ecology; Seals (Animals); Seasonal variations; Seasonal variations; Size; Solar radiation; Sonar; Trematoda; Winter ecology; Zooplankton

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Océanographie, distribution et cycle annuel de la morue arctique (Boreogadus saida) en mer de Beaufort : une approche hydroacoustique   /   Benoit, D.   Fortier, L. [Supervisor]   Simard, Y. [Supervisor]
Québec, Québec : Université Laval, 2012.
xvii, 137 p. : ill., maps ; 28 cm.
Thesis (Ph.D.) - Université Laval, Québec, Québec, 2012.
References.
Indexed a PDF file from the Web.
General and chapter abstracts are provided in both English and French; Introduction générale and Conclusion générale are in French; Chapters 2-4 are in English.
ASTIS record 64587 describes chapter 2 of this thesis as published as a separate manuscript.
ASTIS record 71864 describes chapter 3 as published as a separate manuscript in Open access and with online supplementary material.
ASTIS record 76728.
Languages: English or French
Web: http://www.theses.ulaval.ca/2012/28826/
Libraries: QQLA

Distribution and abundance of fish are greatly determined by trophic interactions and environmental conditions. Climate change in the Arctic constitutes major environmental modifications likely to influence the success of species. Within the pelagic trophic web of the Canadian Arctic, Arctic cod (Boreogadus saida) makes the most part of carbon fluxes between zooplanktonic production and top predators. However, the ecology of adult stages of this key species remains poorly known. This lack of knowledge is mostly attributable to sampling difficulties in the extreme conditions of the Arctic Ocean. Marine acoustics were used in this thesis, coupled with physical and biological oceanographic data, in order to improve the knowledge about Arctic cod's ecology in the Beaufort Sea. A winter time series collected at 230 m deep fixed station in Franklin Bay enabled to uncover winter ecology of Arctic cod. The seasonal scale study showed that under the sea-ice cover, Arctic cod maintained in the lower half of the water column, and was associated with Pacific halocline. Biomass estimates progressively increased from late January (10 g/m³) to reach maximum values in April (2673 g/m³). This Arctic cod accumulation probably resulted from a passive advection within slope waters. The daily scale study revealed the existence of diel vertical migrations of Arctic cod, triggered by the rate of change in light intensity. The nocturnal migration of a part of the population toward surface reflects a behaviour adopted by smaller individuals to feed, reducing at the same time competition with larger individuals and predation by seals. Finally, the study of spatial distribution prior to sea-ice consolidation showed that Arctic cod concentrated on slopes (isobaths 150 to 600 m) of Mackenzie shelf and Amundsen Gulf. Densities were lower (<1 g/m³) than in the winter aggregation and likely constituted the source for the aggregation detected in Franklin Bay. This thesis enabled to characterize the habitat of Arctic cod and trophic interactions that determine its behaviour. Biomass estimates confirmed the importance of this species in the pelagic food web of the Arctic. (Au)

I, D, J, E, G
Animal behaviour; Animal distribution; Animal ecology; Animal food; Animal migration; Animal population; Arctic cod; Bathymetry; Biological sampling; Biomass; Carbon cycling; Chlorophyll; Climate change; Copepoda; Detection; Diurnal variations; Fishes; Light; Marine ecology; Ocean currents; Ocean temperature; Predation; Salinity; Sea ice; Seals (Animals); Seasonal variations; Sonar; Theses; Trophic levels; Water masses; Wildlife habitat; Zooplankton

G0815, G07
Amundsen Gulf, N.W.T.; Arctic Ocean; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Pre-winter distribution and habitat characteristics of polar cod (Boreogadus saida) in southeastern Beaufort Sea   /   Benoit, D.   Simard, Y.   Fortier, L.
(Polar biology, v. 37, no. 2, Feb. 2014, p. 149-163, ill., maps)
References.
ASTIS record 79028.
Languages: English
Web: doi:10.1007/s00300-013-1419-0
Libraries: ACU

Polar cod was shown to form dense under-ice winter aggregations at depth in the Amundsen Gulf (southeastern Beaufort Sea). In this paper, we verify the premises of the aggregation mechanism by determining the distribution and habitat characteristics of polar cod prior to the formation of winter aggregations. Multifrequency split-beam acoustic data collected in October-November 2003 revealed that polar cod split into two distinct layers. Age-0 polar cod formed an epipelagic layer between 0 and ~60 m depth without any clear large-scale biomass trend. In contrast, adult polar cod tended to distribute into an offshore mesopelagic layer between ~200 and 400 m that shoaled into a denser (1-37 g/m²) benthopelagic layer on sloping bottoms (between 150 and 600-m isobaths) along the Mackenzie shelf and into the Amundsen Gulf basin. Concentrations peaked in the Amundsen Gulf where estimated total biomass reached ~250 kt. Both age-0 and adult polar cod distributed in the warmer waters (>-1.4 °C). We hypothesise that polar cod concentration over slopes is governed by the combined actions of (1) local currents concentrating both depth-keeping zooplankton and polar cod at the shelf-break and basin slopes and (2) trophic association with these predictable topographically trapped aggregations of zooplankton prey. During freeze-up, these slope concentrations of polar cod are thought to constitute the main source of the observed dense under-ice winter aggregations. The hypothesis of active short-distance displacements combined with prevailing mean currents is retained as the likely aggregation mechanism. (Au)

I, D, J, G
Age; Animal behaviour; Animal distribution; Animal food; Arctic cod; Bathymetry; Biomass; Diurnal variations; Ocean currents; Sea ice; Seasonal variations; Sonar; Wildlife habitat; Winter ecology

G07
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Walking on thin ice : with Arctic sea ice fast disappearing, a University of Manitoba researcher helps to address issues of sovereignty, environment, and culture = Attention glace fragile! Les glaces marines de l'Arctique sont en train de disparaître rapidement. Il est important de baliser les questions de souveraineté, d'environnement et de culture : un chercheur de l'Universite du Manitoba s'y emploie   /   Bergman, B.
(International Polar Year = Année polaire internationale. Innovation Canada, v. 27, Mar.-Apr. 2007, [7] p., ill.)
Indexed PDF files from the Web.
ASTIS record 61383.
Languages: English and French
Web: http://www.innovationcanada.ca/27/en/pdf/thin_ice.pdf
Web: http://www.innovationcanada.ca/27/fr/pdf/thin_ice.pdf

For many years, David Barber considered himself a climate change skeptic. A sea ice specialist who has worked in the Arctic since 1981, Barber knew from the outset that significant changes in sea ice patterns were occurring. But he put it down to the influence of natural variability. By the mid-1990s, though, mounting evidence of how greenhouse gas emissions are transforming the Earth's climate - with the starkest effects in the Arctic - turned him into a convert. These days, Barber, who is a Canada Research Chair in Arctic System Science at the University of Manitoba, speaks out about the dangers of global warming. He is also responsible for some of the best scientific research to date supporting the need to act on climate change - before it's too late. Over the past five years, Barber has acted as one of the lead investigators on the Canadian Arctic Shelf Exchange Study (CASES). The study brought together 400 scientists from 11 countries to study the ecosystem and climate impacts that have led to and are the result of thinning and disappearing ice in the Arctic Ocean. The CASES research platform is a decommissioned Canadian Coast Guard icebreaker, the Amundsen, which received a $27.7 million retrofit to make it research-ready. In 2003, the CCGS Amundsen made its maiden scientific voyage to the southern Beaufort Sea where the ship was deliberately steered into a thick winter ice pan and trapped for six months. Teams of scientists, working in rotating six-week shifts, probed every conceivable aspect of this remote marine ecosystem. "In the physical world, we studied everything from the bottom of the ocean to the top of the atmosphere," says Barber. "In the biological world, we observed the impact of sea ice on everything from viruses to whales and polar bears." The Amundsen has ferried researchers to the Arctic every year since to do further sampling, and to set up remote observatories as part of an initiative known as ArcticNet. ArcticNet is Canada's only northern Network of Centres of Excellence and the largest Arctic research network in the world. Linking natural, medical, and social science researchers from centres of excellence across Canada - and from 11 other nations - ArcticNet builds on the knowledge and monitoring systems put in place by CASES. The network aims to give a more holistic picture of the impact of climate change by looking at issues such as human health and Inuit settlement patterns. What the scientists have learned is that Arctic sea ice is disappearing at an alarming pace. Satellite data indicates the Arctic is losing multi-year pack ice (as opposed to first-year ice, which forms each fall and thaws at the end of winter) at an annual rate of 74,000 km². That means an area of sea ice nearly the size of Lake Superior melts ever year. Moreover, this has been happening for nearly 30 years, meaning that more than two million km² has been lost so far. At this rate, it's projected there will be no summer ice in the Arctic by 2050 - and perhaps much sooner, if recent trends continue. ... As much as he would like to see these trends slowed, if not reversed, Barber believes it's prudent to first learn more about the long-term effects of global warming on the Arctic ecosystem. To that end, he is spearheading the single largest Canadian project as part of International Polar Year. The $40 million initiative, involving scientists from a dozen nations, will study a phenomenon known as the Circumpolar Flaw Lead (CFL) system, which creates bodies of open water surrounded by sea ice even in the middle of winter. Barber and his fellow researchers will be aboard the Amundsen this winter examining one such CFL system, near Banks Island, Northwest Territories. They will look at what is happening at every level of the ecosystem in a pocket of the Arctic to reflect what the entire region may look like a few decades from now. It's groundbreaking science; borne, unfortunately, out of necessity rather than novelty. . .. (Au)

G, E, J, T, R, D, L
Amundsen (Ship); Animal ecology; ArcticNet Inc.; Biological sampling; Canadian Arctic Shelf Exchange Study; Climate change; Culture (Anthropology); Effects monitoring; Effects of climate on ice; Environmental impacts; Forecasting; Health; Human migration; Ice cover; Ice leads; Icebreakers; International Polar Year 2007-08; Inuit; Marine ecology; Mathematical models; Ocean-atmosphere interaction; Oceanography; Optical properties; Pack ice; Research; Research funding; Research stations; Satellite photography; Science; Sea ice; Sea ice ecology; Social sciences; Solar radiation; Sovereignty; Thawing

G03, G07, G02, G081, G0815
Arctic Ocean; Banks Island waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Northwest Passage; Polar regions


Metazoan meiofauna dynamics and pelagic-benthic coupling in the southeastern Beaufort Sea, Arctic Ocean   /   Bessière, A.   Nozais, C.   Brugel, S.   Demers, S.   Desrosiers, G.
(Polar biology, v. 30, no. 9, Aug. 2007, p.1123-1135, ill., maps)
References.
ASTIS record 63249.
Languages: English
Web: doi:10.1007/s00300-007-0270-6
Libraries: ACU

Pelagic-benthic coupling is relatively well studied in the marginal seas of the Arctic Ocean. Responses of meiofauna with regard to seasonal pulses of particulate organic matter are, however, rarely investigated. We examined the dynamics of metazoan meiofauna and assessed the strength of pelagic-benthic coupling in the Southeastern Beaufort Sea, during autumn 2003 and spring-summer 2004. Meiofauna abundance varied largely (range: 2.3 × 10**5 to 5 × 10**6 ind/m²), both spatially and temporally, and decreased with increasing depth (range: 24-549 m). Total meiofauna biomass exhibited similar temporal as well as spatial patterns as abundance and varied from 25 to 914 mg C/m². Significant relationships between sediment photopigments and various representatives of meiofauna in summer and autumn likely indicate the use of sediment phytodetritus as food source for meiofauna. A carbon-based grazing model provided estimates of potential daily ingestion rates ranging from 32 to 723 mg C/m². Estimated potential ingestion rates showed that meiofauna consumed from 11 to 477% of the sediment phytodetritus and that meiofauna were likely not food-restricted during spring and autumn. These results show that factors governing the distribution and abundance of metazoan meiofauna need to be better elucidated if we are to estimate the benthic carbon fluxes in marginal seas of the Arctic Ocean. (Au)

I, D, B, G, H, J
Animal distribution; Animal food; Animal population; Bathymetry; Benthos; Biological productivity; Biomass; Bottom sediments; Carbon; Carbon cycling; Chlorophyll; Copepoda; Food chain; Marine ecology; Marine fauna; Ocean floors; Ocean temperature; Particulate organic matter; Phytoplankton; Primary production (Biology); Sea ice; Seasonal variations; Temporal variations; Trophic levels

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Contrasting interannual changes in phytoplankton productivity and community structure in the coastal Canadian Arctic Ocean   /   Blais, M.   Ardyna, M.   Gosselin, M.   Dumont, D.   Bélanger, S.   Tremblay, J.-É.   Gratton, Y.   Marchese, C.   Poulin, M.
(Limnology and oceanography, v.?, no.?, 2017, 17 p., ill., maps)
References.
Open access.
This is a contribution to the research programs of ArcticNet, Institut des sciences de la mer de Rimouski, Québec-Océan, and Takuvik.
ASTIS record 83356.
Languages: English
Web: doi:10.1002/lno.10581
Libraries: ACU

The rapid physical changes affecting the Arctic Ocean alter the growth conditions of primary producers. In this context, a crucial question is whether these changes will affect the composition of phytoplankton communities, augment their productivity, and eventually enhance food webs. We combined satellite and model products with in situ datasets collected during fall and provide new insights into the response of phytoplankton biomass and production in the Canadian Arctic by comparing an interior shelf (Beaufort Sea) and an outflow shelf (Baffin Bay). Correlation analysis was used to distinguish between seasonal and interannual variability and revealed that most biological variables are responding to the interannual pressures of climate change. In southeast Beaufort Sea, a change in phytoplankton community composition occurred, with a significant increase in diatoms from 2% (2002) to 37% (2010-2011) of the total protist abundance. In 2011, photosynthetic picoeukaryotes were twice as abundant as in 2002. For these two phytoplankton groups, abundance was correlated with the duration of the open-water period, which also increased and affected vertical stratification and sea-surface temperature. In contrast, there was a sharp decline in centric diatom abundance as well as in phytoplankton biomass and production in northern Baffin Bay over the years considered. These decreases were linked to changes in seasonal progression and sea-ice dynamics through their impacts on vertical stratification and freshwater input. Overall, our results highlight the importance of stratification and the duration of the open-water period in shaping phytoplankton regimes-either oligotrophic or eutrophic- in marine waters of the Canadian Arctic. (Au)

H, D, G, E, F
Biomass; Chemical oceanography; Chlorophyll; Climate change; Diatoms; Eutrophic lakes; Marine ecology; Mathematical models; Oligotrophic lakes; Photosynthesis; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Plant taxonomy; Primary production (Biology); River discharges; Satellite photography; Sea ice; Seasonal variations; Solar radiation; Temporal variations; Water masses

G03, G07, G09
Arctic Ocean; Baffin Bay-Davis Strait; Canadian Beaufort Sea


Geologic features and seabed processes of the Northwest Passage   /   Blasco, S.M.   Bennett, R.   MacLean, B.   Hughes Clarke, J.   Beaudoin, J.   Blasco, K.A.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 186
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67105.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Multibeam sonar systems have been utilized for mapping of seabed transects through the Northwest Passage and Canadian Beaufort Shelf. Survey platforms include the CCGS Amundsen, equipped with a hull-mounted Simrad EM300 multibeam sonar and the CCGS Nahidik which carries a 9 m launch equipped with a Simrad EM3002 multibeam sonar. Multibeam data combined with 3.5 kHz sub-bottom data have been collected in support of seabed issues related to the opening of the Northwest Passage including: sovereignty, safe navigation, geohazards to resource development, paleoceanography, geological evolution of the seabed, and benthic ecosystem investigations. Navigation hazards include shoals and submerged artificial islands. Geohazards related to offshore hydrocarbon development include unstable foundation conditions, slope instabilities, shallow gas and oil seeps, faulting and scouring by sea-ice and icebergs. Holocene sediment depocentres have been located for sediment sampling for high resolution paleoenvironmental reconstructions. Flutings and drumlinized seabed clearly define the flow patterns of glacial ice streams. Seabed morphology and backscatter mapping provide the framework for benthic ecosystem assessments. Data analyzed to date have contributed significantly to the knowledge and understanding of seabed processes, geohazards, geological features and history of the seabed of the Northwest Passage and Beaufort Shelf. (Au)

A, B, G, L, J, I, F, Q
Benthos; Bottom sediments; Drumlins; Faults (Geology); Geology; Glacial erosion; Glaciers; Ice scouring; Icebergs; Landslides; Marine ecology; Marine navigation; Natural gas seeps; Ocean floors; Offshore gas fields; Offshore oil fields; Oil seeps; Sea ice; Sedimentation; Sonar; Submarine topography

G07, G0815, G09
Baffin Bay-Davis Strait; Canadian Arctic Islands waters; Canadian Beaufort Sea; Northwest Passage


Physical characteristics of polar bear winter sea ice habitat   /   Blouw, C.   Barber, D. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2008.
xi, 114 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR48954)
ISBN 9780494489543
Appendix.
References.
Thesis (M.Sc.) - University of Manitoba, Winnipeg, Man., 2008.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74963.
Languages: English
Libraries: OONL MWU

Accumulation of dynamic and thermodynamic forces in the Arctic are decreasing the extent of thin annual sea ice which polar bear rely on for survival. It is imperative that we identify the preferred habitat of polar bears to fully understand their future requirements. In this thesis, surveys of polar bear tracks and the surrounding sea ice variables, at various scales, were recorded. Sea ice roughness was measured through surveys of the sample area in situ, with an electromagnetic induction (EM) system (IcePIC) mounted to a helicopter, and analyzed through advanced synthetic aperture radar (ASAR) images of the study area. In situ Polar tracks provided a limited association with the EM sea ice roughness and a negative association to ASAR sea ice roughness. Results indicate a significant association between EM mean values and ASAR brightness means. In addition, EM statistics and ASAR texture statistics were correlated through a best fit regression model. These associations display a remote method to identify preferred polar bear habitat and provide a potential linkage between the regional (EM) and remotely sensed (ASAR) assessment of sea ice roughness. (Au)

J, I, G, F, E
Aerial surveys; Albedo; Animal behaviour; Animal distribution; Animal food; Animal population; Animal tracks; Classification; Climate change; Denning; Effects of climate on ice; Fast ice; Gender differences; Geographical positioning systems; Helicopters; Ice cover; Mathematical models; Physical properties; Polar bears; Predation; Pressure ridges; SAR; Sea ice; Sea ice ecology; Seals (Animals); Snow; Snowmobiles; Surface properties; Temporal variations; Thermodynamics; Theses; Wildlife habitat

G0812, G0814
Amundsen Gulf region, N.W.T.; Amundsen Gulf, N.W.T.


Population structure in polar cod (Boreogadus saida) : first results from a circumpolar study using microsatellites   /   Bouchard, C.   Madsen, M.L.   Fevolden, S.-E.   Fortier, L.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 187-188
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67107.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

The importance of polar cod in the Arctic marine food web is well documented. However, very few information is available for other aspects of the species biology. Migration patterns and breeding structure are almost unknown but some indices about those could be unveiled by the study of population structure using genetic tools. So far, the genetic analyses carried out with polar cod, using fish from a restricted geographical range and genetic markers which are not extremely powerful to detect low genetic differentiation, revealed no population structure. Here, we present a population structure study with samples of polar cod from several locations around the Arctic (Beaufort, Laptev and East Siberian seas, Hudson, Baffin and Iqualuit bays, Oliver, Lancaster and Scoresby sounds, Amundsen and Boothia gulfs, Kongsfjord) analyzed with recently-developed microsatellites markers. As expected from the geographic locations and major currents within the Arctic Ocean, the largest genetic differentiation is found between Canadian and Siberian fish (Fst between 0.0138 and 0.0643) while the lowest is found between samples from the eastern part of the Canadian Arctic Archipelago (Baffin and Iqualuit bays, Oliver and Lancaster sounds, Fst between 0.0000 and 0.0052). Low genetic differentiation between distant locations (Hudson Bay and Beaufort Sea, for example) still need to be explained but could support one of our hypothesis about population sub-structure in polar cod. (Au)

I
Arctic cod; Biological sampling; Genetics

G141, G07, G0815, G0814, G09, G12
Amundsen Gulf, N.W.T.; Baffin Bay-Davis Strait; Boothia, Gulf of, Nunavut; Canadian Beaufort Sea; Frobisher Bay, Nunavut; Hudson Bay; Kongsfjorden, Svalbard; Lancaster Sound, Nunavut; Laptevykh More; Oliver Sound, Nunavut; Scoresby Bay, Nunavut; Vostochno-Sibirskoye More


Contrasting the early life histories of sympatric Arctic gadids Boreogadus saida and Arctogadus glacialis in the Canadian Beaufort Sea   /   Bouchard, C.   Mollard, S.   Suzuki, K.   Robert, D.   Fortier, L.
(Ecology of arctic gadids / coordinated by F. Mueter, J. Nahrgang, J. Nelson and J. Berge. Polar biology, v. 39, no. 6, June 2016, p.1005-1022, ill., maps)
References.
ASTIS record 79917 describes the thesis to which this independently published manuscript relates.
ASTIS record 80296.
Languages: English
Web: doi:10.1007/s00300-014-1617-4
Libraries: ACU

The early life stages of Boreogadus saida and Arctogadus glacialis are morphologically similar, making it difficult to assess differences in their ecological niche. The present study documented for the first time the early life stage ecology of A. glacialis, compared it to that of B. saida, and identified the factors separating the niches of the two sympatric species. The 10,565 larval gadids collected in the Beaufort Sea from April to August of 2004 and 2008 were identified to species either directly by genetics and/or otolith nucleus size, or indirectly with a redistribution procedure. Between 8.0 and 8.7 % of all gadids were assigned to A. glacialis. Larvae of A. glacialis were longer at hatch and experienced lower mortality rates than those of B. saida. The two species shared similar spatiotemporal and vertical distributions, hatching season, and growth rate. Under the ice, feeding incidence of B. saida was low (14 %) relative to A. glacialis (88 %). At lengths <15 mm, both species specialized on different prey. The diet of fish >15 mm overlapped (Schoener's index = 0.7), with Calanus glacialis and C. hyperboreus providing >50 % of the carbon intake of both species. The higher mortality in B. saida may be explained by the smaller size at age from hatching to metamorphosis and a lower under-ice feeding incidence. The early larval stage appears to be the key period of niche divergence between the two species. (Au)

I, D, F, G, J, E
Age; Animal distribution; Animal ecology; Animal food; Animal growth; Animal mortality; Arctic cod; Biological sampling; Fish larvae; Fish spawning; Genetics; Ice cover; Marine ecology; Plankton; Predation; Size

G07, G0815
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Discrimination of first year sea ice deformation features using synthetic aperture radar   /   Breneman, C.L.   Yackel, J. [Supervisor]
Calgary, Alta. : University of Calgary, 2006.
xi, 112 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR13539)
ISBN 0494135395
Thesis (M.Sc.) - University of Calgary, Calgary, Alta., 2006.
Appendices.
References.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74970.
Languages: English
Libraries: ACU OONL

Multiple image classifications are performed to examine the effect of system parameters (i.e. polarization and incidence angle) and image processing techniques (i.e. texture and adaptive filters) on discriminating first year sea ice deformation features in ENVISAT ASAR imagery. Results indicate that images acquired at higher incidence angles improve the discrimination of sea ice deformation features. Co-polarizations images: VV (khat=0.576) and HH (0.559) produce considerably higher classification accuracies than the cross-polarizations HV/VH (0.300). Applying speckle filters to the ENVISAT ASAR imagery is found to considerably improve classification accuracy. In an attempt to further improve classification results, texture measures are incorporated with speckle filtered imagery but lower the classification accuracy in all cases. These results indicate that the optimal choice for discriminating FYI sea ice deformation from 12.5m resolution ASAR data is gamma filtered (7x7 window size) HH VV polarization imagery acquired at swath 7 (~45°). (Au)

G, F, A, E, D
Albedo; Atmospheric temperature; Classification; Climate change; Clouds; Deformation; Density; Diurnal variations; Effects of climate on ice; Energy budgets; Fast ice; Formation; Ice floes; Ice leads; Instruments; Laser profilometry; Mathematical models; Measurement; Melting; Ocean currents; Ocean-atmosphere interaction; Physical properties; Pressure ridges; Radar; Remote sensing; Salinity; SAR; Satellites; Sea ice; Seasonal variations; Snow; Snow surveys; Snowmelt; Solar radiation; Spatial distribution; Surface properties; Temperature; Temporal variations; Thermal properties; Thermal regimes; Thermodynamics; Theses; Thickness; Winds

G0815
Amundsen Gulf, N.W.T.; Franklin Bay, N.W.T.


Reconstruction of late Holocene sea surface parameters on the Mackenzie Slope (Beaufort Sea, Canadian Arctic) : preliminary results   /   Bringué, M.   Rochon, A.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 189-190
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67110.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

This study aims at reconstructing past sea-surface parameters in the Beaufort Sea area (Western Canadian Arctic) on the base of sedimentary cores collected over the Mackenzie slope, and covering the last 4500 years. Piston, trigger and box cores were sampled at station 803 (70°38'N, 135°55'W) in 2004 aboard the CCGS Amundsen (CASES) at 218 m water depth. Sedimentation at this particular location is influenced by both the Beaufort gyre and the Mackenzie River, whose sedimentary discharge is by far the largest among all other Arctic rivers. Dinoflagellate cysts are used as proxies for paleoceanographic reconstructions. Past sea-surface temperature, salinity, sea-ice cover and productivity are estimated using transfer functions (modern analogue technique). Other palynomorphs such as freshwater algae (Halodinium, Pediastrum) and reworked material provide insight on the freshwater input (via the Mackenzie), and thus the hydroclimatic conditions over the late Holocene. Preliminary results from the upper 330 cm of the piston core are presented. According to the age model based on 4 AMS-14C datations along the core, this section represents the last 2600 calibrated years BP and the core was subsampled at a 10 cm interval. Dinocyst concentrations are relatively low throughout the section (from 198 to 1240 cysts/cm³). Dinocyst zone II (from 2600 to 1600 cal yr BP) is characterized by assemblages dominated by Operculodinium centrocarpum (~45% on average), accompanied by Islandinium minutum (~19%) and cysts of Pentapharsodinium dalei (~15%). Assemblages in dinocyst zone I (from 1600 cal yr BP to present) are dominated by I. minutum (~31% on average), with the accompanying taxa O. centrocarpum (~26%) and P. dalei (~20%). Changes in dinoflagellate cyst assemblages between zone I and zone II provide insights that are expressed quantitatively by transfer function analyses. In zone I, at the base of the core, summer sea-surface temperatures decrease up to 2°C below present value, as the duration of sea ice cover increases by 1 month a year (below actual value). The autotroph vs heterotroph (G:P) dinoflagellate ratio drops from 3.14 to 0.38, which suggests limited primary productivity due to increasing sea ice cover during this period. In zone II (from 1600 cal yr BP to present), summer sea-surface temperatures increase to reach modern value, and a decrease in duration of sea ice cover is observed. The G:P ratio increases up to 3.12 at the top of the core. These data are consistent with similar studies held in adjacent areas. It is also consistent with other studies describing the warming of Western Canadian Arctic, in comparison with a cooling Eastern Arctic. Spectral and wavelet analysis will also be run on the entire dataset in order to document hydroclimatic cycle(s) prevailing in the Beaufort Sea area, such as the Arctic Oscillation. These results will provide useful data on the evolution of sea surface conditions in the Western Canadian Arctic for the late Holocene as well as for the hydroclimatic variability (freshwater inputs). This will contribute to document the natural variability of Arctic's climate, a key component in the understanding of earth's warming climate. (Au)

B, D, H, I, G, E
Algae; Animal distribution; Biological productivity; Bottom sediments; Climate change; Cores; Dinoflagellata; Ice cover; Ocean temperature; Palynomorphs; Radiocarbon dating; Recent epoch; Salinity; Sea ice; Sedimentation; Temporal variations

G07
Canadian Beaufort Sea


Late Holocene paleoceanography and climate variability over the Mackenzie Slope (Beaufort Sea, Canadian Arctic)   /   Bringué, M.   Rochon, A.
In: ArcticNet programme 2009 : annual scientific meeting, 8-11/12/2009, Victoria, B.C. = ArcticNet programme 2009 : réunion scientifique annuelle, 8-11/12/2009, Victoria, B.C. - [Québec, Québec] : ArcticNet, 2009, p. 28
Abstract of a Topical Session presentation.
Indexed a PDF file from the Web.
ASTIS record 73526.
Languages: English
Web: http://www.arcticnetmeetings.ca/asm2009/docs/asm2009_programme_long.pdf
Libraries: ACU

Late Holocene paleoceanography and climate variability of the Southeastern Beaufort Sea (Canadian Arctic) have been investigated on the basis of sedimentary cores collected over the Mackenzie Slope. Piston, trigger and box cores were sampled at station 803 in 2004 aboard the CCGS Amundsen at 218 m water depth. The chronology of the piston core is constrained by 4 AMS-14C dates, and the sedimentation rate in the box core is assessed from 210Pb data. We obtain a continuous composite sequence covering the last 4600 years, with a sedimentation rate of ~140 cm/kyr. Palynological data reveal that dinocyst assemblages are dominated by Operculodinium centrocarpum (mean of 43.3%), with the accompanying taxa Brigantedinium spp. (19.6%), Islandinium minutum (15.6%) and cysts of Pentapharsodinium dalei (13.7%). Four zones have been established on the basis of dinocyst relative abundances. Dinocyst assemblage zone 1 (D1), from 4600 to 2700 cal BP, is dominated by O. centrocarpum (mean of 49,0%). In zone D2 (2700-1500 cal BP), the relative abundance of O. centrocarpum decreases (34,4%) in favour of that of the opportunistic, heterotrophic taxa Brigantedinium spp. (28,8%) and cysts of Polykrikos sp. var. arctic/quadratus (2,8%). This shift is also illustrated by the decrease of the ratio Gonyaulacales versus Peridiniales, a trend observed in both zones D2 and D3. In fact, dinocyst zone D3 (1500-30 cal BP or 450-1920 AD) is characterized by the high relative abundance of the peridinioid taxa I. minutum (19,9%). The uppermost zone (D4), spanning from 1920 to 2004 AD, is again dominated by O. centrocarpum (44,5%), and shows low relative abundances of Brigantedinium spp. and cf. Echinidinium karaense. Quantitative reconstructions of past sea-surface parameters (August sea-surface temperature: SST, August sea-surface salinity: SSS, and duration of sea-ice cover) have been assessed on the basis of dinocyst assemblages using transfer functions (modern analogue technique). They indicate relatively stable conditions over the last 4,6 ka, with episodic cooling events (SST of ~1,5°C below the modern value of 6°C) that took place between 700 and 1820 AD. We associate the last and the longest of these cooling events (1560 - 1820 AD) with the Little Ice Age. Reconstructed SSS shows decadal oscillations since 1920 AD that we tentatively associate with the accumulation of freshwater by the Beaufort Gyre and the subsequent Great Salinity Anomalies. Our data suggest that similar salinity anomalies could have occurred around ~1860 and ~1790 AD. Stable isotopic data (delta 13C and delta 15N) suggest that the rate of relative sea-level rise in the southern Beaufort Sea increased since 1820 AD. This constitutes a major concern with regard to present and future coastal erosion. The delta 15N profile might also have recorded variations in Pacific water influence from 4600 to ~1300 cal BP, probably associated with centennial-scale shifts of the Arctic Oscillation phases. (Au)

B, D, H, I, G, E, A
Algae; Animal distribution; Biological productivity; Bottom sediments; Climate change; Coast changes; Cores; Dinoflagellata; Erosion; Ice cover; Isotopes; Nitrogen; Ocean temperature; Oxygen; Palaeoclimatology; Palaeohydrology; Palynomorphs; Radiocarbon dating; Recent epoch; Salinity; Sea ice; Sea level; Sea water; Sedimentation; Temporal variations

G07
Canadian Beaufort Sea


Paléocéanographie et variabilité climatique sur le talus du Mackenzie (Mer de Beaufort, Arctique canadien) au cours de l'Holocène récent   /   Bringué, M.   Rochon, A. [Supervisor]
Rimouski, Québec : Université du Québec à Rimouski, 2009.
xiv, 90 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR67430)
ISBN 978-0-494-67430-7
Appendices.
References.
Thesis (M.Sc.) - Université du Québec à Rimouski, Rimouski, Québec, 2009.
Front material, general introduction, and general conclusion in French; chapter 2 is in English: Late Holocene paleoceanography and climate variability over the Mackenzie slope (Beaufort Sea, Canadian Arctic) / Manuel Bringué and André Rochon. Abstract provided in French.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 75514.
Languages: English or French
Web: http://semaphore.uqar.ca/270/
Libraries: QRU OONL

Une séquence sédimentaire prélevée sur le talus du Mackenzie (station CASES 2004-804-803, mer de Beaufort, Arctique canadien) à 218 m de profondeur a permis de documenter la variabilité hydroclimatique au cours des derniers 4600 ans à cet emplacement clé de l'Arctique occidental. La sédimentation y est à la fois influencée par la gyre de Beaufort (impliquée dans le transport des glaces et dans les principaux modes de variabilité hydroclimatiques telle l'Oscillation arctique) et la décharge sédimentaire du Mackenzie, de loin le plus important tributaire de l'Océan Arctique. La chronologie de la carotte à piston (longueur: ~ 6 m) a été déterminée sur la base de quatre datations AMS-14 C sur des coquilles de bivalves. Le taux de sédimentation résultant est extrêmement similaire à celui estimé à partir de mesures d'activité de 210Pb sur les premiers 20 cm de la carotte boîte. La carotte à gravité ayant été corrélée stratigraphiquement à la carotte à piston, on obtient une séquence composite complète couvrant les derniers 4600 ans, avec un taux d'accumulation constant de 140 cm/ka. Les reconstitutions quantitatives des paramètres océaniques de surface (température et salinité de surface en août, durée du couvert de glace) ont été estimées à partir des assemblages de kystes de dinoflagellés dans les sédiments en utilisant des fonctions de transfert (méthode des meilleurs analogues modernes). Celles-ci indiquent des conditions de surface relativement stables au cours des derniers 4600 ans. Cependant, des refroidissements épisodiques d'environ 1,5°C sous la valeur actuelle (5,9°C) sont enregistrés entre 700 et 1820 AD, possiblement reliés à l'advection d'eau pacifique froide (valeurs négatives de l'index PDO - Pacific Decadal Oscillation ). Nous associons le dernier et le plus long de ces refroidissements (1560-1820 AD) avec le Petit Âge Glaciaire. De 1920 à 2004 AD, des variations récurrentes de salinité de surface (oscillant entre ~21 et 27) peuvent être associéesau mécanisme d'accumulation d'eau douce par la gyre de Beaufort pendant les régimes de circulation atmosphérique anticyclonique. Nos données indiquent également que des accumulations d'eau douce similaires (qui précèdent les anomalies de salinité documentées dans l'Atlantique Nord) ont pu survenir vers 1790 et 1860 AD. Les données isotopiques (delta 13 C et delta 15 N) indiquent une lente augmentation de l'influence marine (vs terrestre) dans l'origine de la matière organique au cours de l'Holocène récent. Cette variation est attribuable au rehaussement du niveau marin relatif dans la région du delta du Mackenzie, une région côtière particulièrement vulnérable à l'érosion. Nos données suggèrent également que le taux de transgression marine s'est intensifié depuis 1820 AD. Entre 4600 et 1300 cal avant aujourd'hui, des variations séculaires de l'Oscillation arctique sont enregistrées par les mesures de delta 15 N qui mettent en évidence des modifications de l'influence de l'eau pacifique au site d'étude. Ainsi, cette étude à haute résolution a permis de documenter la variabilité hydroclimatique arctique au-delà des mesures instrumentales récentes. Des changements hydrographiques importants ont pu être mis en évidence au sein de la stabilité climatique relative de l'Holocène récent. (Au)

B, A, D, H, I, F, E, J, G
Bathymetry; Bottom sediments; Carbon; Ciliata; Climate change; Climatology; Copepoda; Cores; Dinoflagellata; Foraminifera; Geochemistry; Hydrology; Ice cover; Isotopes; Lakes; Nitrogen; Ocean currents; Ocean temperature; Palaeoclimatology; Palaeoecology; Palaeohydrology; Palynology; Palynomorphs; Plant distribution; Pollen; Radioactive dating; Radiocarbon dating; Radionuclides; Recent epoch; Salinity; Sea ice; Sea level; Sedimentation; Size; Spatial distribution; Spores; Stratigraphy; Temporal variations; Theses; Water masses

G07, G0812
Barents Sea; Canadian Beaufort Sea; Greenland; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea; Victoria Island, N.W.T./Nunavut


Late Holocene paleoceanography and climate variability over the Mackenzie Slope (Beaufort Sea, Canadian Arctic)   /   Bringué, M.   Rochon, A.
(Marine geology, v.291-294, 1 Jan. 2012, p. 83-96, ill., maps)
References.
ASTIS record 75375.
Languages: English
Web: doi:10.1016/j.margeo.2011.11.004
Libraries: ACU

Late Holocene paleoceanography and climate variability of the Southeastern Beaufort Sea (Canadian Arctic) have been investigated on the basis of sedimentary cores collected over the Mackenzie Slope. Piston, trigger and box cores were sampled at station 803 in 2004 aboard the CCGS Amundsen at 218 m water depth. The chronology of the piston core is constrained by 4 AMS-14C dates, as the sedimentation rate in the box core is assessed from 210Pb data. We obtain a continuous composite sequence covering the last 4600 years, with a sedimentation rate of ~ 140 cm/kyr. Transfer functions (modern analogue technique) based on dinoflagellate cyst (dinocyst) assemblages were used to reconstruct the evolution of sea-surface conditions over the time period covered by the cores. Palynological data reveal that dinocyst assemblages are dominated by Operculodinium centrocarpum sensu lato (mean of 43.3%) throughout the core, with the accompanying taxa Brigantedinium spp. (19.6%), Islandinium minutum (15.6%) and cysts of Pentapharsodinium dalei (13.7%). Four zones have been established on the basis of dinocyst relative abundances. Dinocyst assemblage zone 1 (D1), from 4600 to 2700 cal years BP, is dominated by O. centrocarpum (mean of 49.0%). In zone D2 (2700-1500 cal years BP), the relative abundances of O. centrocarpum decrease (34.4%) in favour of the opportunistic, heterotrophic taxa Brigantedinium spp. (28.8%) and cysts of Polykrikos sp. var. arctic/quadratus (2.8%). Dinocyst zone D3 (1500-30 cal years BP or 450-1920 AD) is characterised by the high relative abundance of the peridinioid taxa I. minutum (19.9%). The last zone (D4), spanning from 1920 to 2004 AD, is again dominated by O. centrocarpum (44.5%), and shows low relative abundances of Brigantedinium spp. and cf. Echinidinium karaense. Quantitative reconstructions of past sea-surface parameters (August sea-surface temperature: SST, August sea-surface salinity: SSS, and duration of sea-ice cover) indicate relatively stable conditions over the last 4.6 kyr, with episodic cooling events (SST of ~1.5 °C below the modern value of 6 °C) that took place between 700 and 1820 AD. We associate the last and the longest of these cooling events (1560-1820 AD) with the Little Ice Age. Reconstructed SSS shows decadal oscillations since 1920 AD that we tentatively associate with the accumulation of freshwater by the Beaufort Gyre and the subsequent Great Salinity Anomalies. Our data suggest that similar salinity anomalies could have occurred ca. 1860 and 1790 AD. Stable isotopic data show a slight increase in delta 13C values (from ~-27.1‰ at the base to ~-25.8‰ at the top) over the last 4.6 kyr that we associate with the gradual increase in atmospheric CO2 concentration as recorded by Antarctic ice cores. Variations in the delta 15N profile suggest variations in Pacific water influence from 4600 to ~1300 cal years BP, associated with centennial scale shifts of the Arctic Oscillation phases. (Au)

B, D, F, H, I, G, E, J
Bottom sediments; Carbon; Cores; Dinoflagellata; Ice cover; Isotopes; Lead; Nitrogen; Ocean currents; Ocean temperature; Palaeoclimatology; Palaeoecology; Palaeohydrology; Palynology; Palynomorphs; Plant distribution; Radioactive dating; Radiocarbon dating; Radionuclides; Recent epoch; River discharges; Salinity; Sea ice; Sea level; Sedimentation; Size; Spatial distribution; Temporal variations; Water masses

G07, G0812
Canadian Beaufort Sea; Mackenzie River, N.W.T.


Does sea ice retreat shape the size structure of phytoplankton in the Amundsen Gulf?   /   Brugel, S.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 191-192
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67114.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

In June 2004, the size structure of the phytoplankton community was investigated in the upper water column (50 m) of the Amundsen Gulf region in relation to sea ice dynamic. In order to characterized the phytoplankton size structure, we used total and fractionated (5 and 20 µm) chl a concentrations and the size fractionation of small phytoplankton (<20 µm) abundance by flow cytometry (<3 µm, picophytoplancton and >3 µm, nanophytoplankton). South of the Amundsen Gulf, sea ice retreat occurred later compared to the northern areas, and was fast (one week). There, the phytoplankton community was under pre-bloom conditions with a biomass due to <20 µm cells. Picophytoplankton abundances were 4 to 5-fold higher than their abundance under ice in the area, suggesting that picophytoplankton responded faster to sea ice retreat than larger phytoplankton cells. In the middle of the Amundsen Gulf, sea ice retreat lasted 2.5 weeks and this area was free of ice since one week. The phytoplankton community was already in post-bloom situation, under nitrate depletion with low phytoplankton biomass and contribution of >5 µm cells, though no deep chlorophyll maximum was detected. Moreover, picophytoplankton abundances were high while nanophytoplankton abundances were only moderate. Finally, at stations close the eastern part of the Mackenzie shelf and slope, sea ice retreat was only slightly faster (two weeks), but the phytoplankton size structure was very different from the middle of the Amundsen Gulf and formed a deep maximum of biomass and <20 µm cells abundance. Over the upper water column, at least 40% of the biomass was due to >20 µm cells, although <20 µm cells were abundant, and particularly nanophytoplankton. Overall, phytoplankton growth in spring in the Amundsen Gulf seemed closely linked to sea ice dynamics. Slow ice retreat seemed to favour high picophytoplankton growth, while fast sea ice retreat favoured the growth of pico-, nanophytoplankton and >20 µm phytoplankton and their accumulation at depth. (Au)

H, G
Biomass; Breakup; Chlorophyll; Marine biology; Melting; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Sea ice; Size

G0815
Amundsen Gulf, N.W.T.


Phytoplankton biomass and production in the southeastern Beaufort Sea in autumn 2002 and 2003   /   Brugel, S.   Nozais, C.   Poulin, M.   Tremblay, J.-É.   Miller, L.A.   Simpson, K.G.   Gratton, Y.   Demers, S.
(Marine ecology. Progress series (Halstenbek), v.377, Feb. 26, 2009, p. 63-77, ill., maps)
References.
ASTIS record 71789.
Languages: English
Web: doi:10.3354/meps07808
Libraries: AEU

The phytoplankton community of the Mackenzie shelf and the Amundsen Gulf (southeastern Beaufort Sea) was characterized (e.g. chlorophyll a biomass, primary production and taxonomy) during autumn 2002 (23 September to 14 October) and 2003 (30 September to 14 November). Spatial differences were evident, particularly in early autumn. Total phytoplankton biomass and the contribution of large cells (>5 µm) to biomass were higher in the Amundsen Gulf than on the Mackenzie shelf. The community of autotrophic cells (>10 µm) was numerically dominated by diatoms in the Amundsen Gulf and by dinoflagellates on the Mackenzie shelf. The abundance of chlorophytes revealed the influence of the Mackenzie River on the Mackenzie shelf. Contrary to 2002, when all measurements were from early October, the phytoplankton community of the Amundsen Gulf in 2003 presented the characteristics of a late bloom, which presumably peaked in late September. In early autumn, however, primary production rates were similar for both years, averaging 75 mg C/m²/d. High primary production-to-biomass ratios and overall dominance of small cells (<5 µm) suggest that pelagic production in the southeastern Beaufort Sea was sustained by active recycling. During autumn 2003, a temporal decrease in phytoplankton biomass and primary production likely resulted from decreasing light availability. Overall, the autumnal primary production estimated in this study, from mid-September to the end of October, could increase the annual primary production previously estimated for the Beaufort Sea by 15%. (Au)

H, D, G, E
Biomass; Chemical oceanography; Chlorophyll; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Plant taxonomy; Primary production (Biology); River discharges; Sea ice; Seasonal variations; Solar radiation; Temporal variations

G0815, G03, G07, G0812
Amundsen Gulf, N.W.T.; Canada Basin, Arctic Ocean; Canadian Beaufort Sea; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.


Étude des variations spatiales et temporelles du phytoplancton en mer de Beaufort : biomasse, production et structure de taille des communautés   /   Brugel, S.   Demers, S. [Supervisor]
Rimouski, Québec : Université du Québec à Rimouski, 2009.
xiii, 163 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR64727)
ISBN 978-0-494-64727-1
References.
Thesis (Ph.D.) - Université du Québec à Rimouski, Rimouski, Québec, 2009.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
Abstract, general introduction and general conclusions in French, with Chapters 1, 2, and 3 in English.
Chapters 1-3 are presented in the form of journal articles and have both English and French abstracts.
Chapter 1, published in Marine Ecology Progress series, is described in ASTIS record 71789.
ASTIS record 74964.
Languages: English or French
Web: http://semaphore.uqar.ca/109/
Libraries: ACU QRU

Cette thèse de doctorat est consacrée à l' étude des variations spatiales et temporelles du phytoplancton du sud-est de la mer de Beaufort, comprenant le plateau continental du Mackenzie et le golfe d'Amundsen, au cours de la période libre de glace. La communauté phytoplancton que a été caractérisée par la biomasse, la production primaire et la structure de taille du phytoplancton <20 µm. En automne en 2002 et 2003, la biomasse phytoplanctonique et la contribution des cellules >5 µm étaient plus élevées dans le golfe d'Amundsen que sur le plateau continental du Mackenzie. Au début de l'automne 2003, la communauté phytoplanctonique du golfe d'Amundsen présentait les caractéristiques d'une efflorescence automnale, qui aurait possiblement culminé à la fin du mois de septembre. Les proportions élevées de production primaire par rapport à la biomasse et la dominance générale des cellules <5 µm suggéraient que la production automnale en mer de Beaufort était entretenue par un recyclage actif. En automne 2003, la diminution de la biomasse phytoplanctonique et de la production primaire au cours du temps était probablement due à la diminution de la disponibilité en lumière. Au printemps et en été 2004, les différences de distribution spatiale étaient également marquées. En juin, la communauté phytoplanctonique était dans une situation de pré-bloom dans le sud du golfe d'Amundsen, et en situation de post-bloom au centre du golfe, en raison de l'ouverture précoce de la polynie du Cap Bathurst. Dans le golfe d'Amundsen, la biomasse chlorophyllienne, ainsi que la contribution des cellules >5 µm, restaient faibles du printemps à l'été. Par contre, sur le plateau continental du Mackenzie, les phénomènes d'upwelling liés au vent et l'extension du panache des eaux du fleuve Mackenzie favorisaient la production phytoplanctonique, en augmentant la biomasse chlorophyllienne due aux cellules >20 µm et 1'export potentiel de production primaire en profondeur. En général, les proportions élevées de production primaire par rapport à la biomasse, ainsi que l'absence d'accumulation de cellules >5 µm dans le golfe d'Amundsen, suggéraient une forte pression de broutage sur le phytoplancton et un recyclage actif. Dans le golfe d'Amundsen, la production primaire annuelle a été estimée à 21 g/C/m²/a. Cette faible valeur résulte probablement d'une sous-estimation liée à 1'extrapolation, mais également du faible niveau hivernal de nitrates, qui pré-conditionnait vraisemblablement faible production phytoplanctonique annuelle. La structure de taille du phytoplancton <20 µm a été étudiée en automne 2003 et au printemps et en été 2004. Le picophytoplancton (<3 µm) dominait le phytoplancton <20 µm en abondance pendant toutes les saisons. Dans le golfe d'Amundsen, le picophytoplancton répondait plus rapidement que le nanophytoplancton au retrait printanier des glaces. De plus, les conditions de retrait des glaces modelaient la structure de taille du phytoplancton <20 µm. En outre, en été, la circulation et la fonte de glace mobile favorisaient la croissance du pico- et du nanophytoplancton de 3-10 µm. En automne, la diminution de la disponibilité en lumière était probablement responsable de la chute de 1'abondance du phytoplancton <20 µm. Sur le plateau continental du Mackenzie, le phytoplancton <20 µm était dominé, au large, par le picophytoplancton en été et en automne, alors que, prés de la côte, le picophytoplancton était moins dominant en été qu'en automne. Le panache des eaux du fleuve Mackenzie était probablement une source de cellules de plus grande taille en été (nanophytoplancton) qu'à la fin de l'automne (pico- et nanophytoplancton de 3-10 µm). En général, les cellules picophytoplanctoniques étaient fortement retenues dans les eaux de surface, et entretenaient probablement un réseau trophique microbien très actif. Cette étude souligne l'importance des cellules phytoplanctoniques de petite taille (<3-5 µm) dans le réseau trophique de la mer de Beaufort. Ces cellules dominaient la biomasse et la production pour la plus grande partie de la période libre de glace, notamment dans le golfe d'Amundsen oú la dynamique du couvert de glace semble être le principal facteur de variations spatio-temporelles. Par contre, sur le plateau continental du Mackenzie les apports d'eaux douces du fleuve Mackenzie et les phénomènes d'upwelling le long du talus continental favoriseraient épisodiquement la production de cellules phytoplanctoniques de grande taille. (Au)

D, H, G, J
Bathymetry; Benthos; Biological productivity; Biomass; Carbon; Carbon cycling; Chlorophyll; Fluorometry; Ice cover; Marine ecology; Ocean temperature; Photosynthesis; Phytoplankton; Primary production (Biology); River discharges; Sea ice; Seasonal variations; Temporal variations; Theses; Trophic levels

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Phytoplankton light absorption properties in the Arctic regions : a global view   /   Brunelle, C.B.   Larouche, P.   Doxaran, D.   Babin, M.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 188
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67109.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

The Arctic Ocean is currently experiencing major ecosystem changes due to the accelerated decline of its summer sea ice cover. This is virtually opening a whole new ocean for phytoplankton to grow. Due to its remoteness, this region is however hard to sample using traditional ship-based approaches. Remote sensing appears as a promising way to monitor the ecosystem changes that are likely to occur with the shrinking sea ice cover. Remote sensing of phytoplankton biomass and of derived products such as primary production are fundamentally determined by the inherent optical properties of phytoplankton, dissolved matter and non algal particles. Previous studies conducted in arctic coastal waters showed that current operational algorithms were generally overestimating chlorophyll concentrations due to the presence of dissolved and suspended matter and because of significant pigment packaging in the arctic phytoplankton species. The light absorption capacity of phytoplankton (aph) is thus the key to the accurate monitoring of possible climate change effects in the Arctic Ocean. To evaluate this parameter for arctic waters, we thus gathered a new set of measurements of aph as part of a series of expeditions: the Canadian Arctic Shelf Exchanges Study (CASES) field program conducted in 2003 and 2004; the Circumpolar Flaw Lead study in 2007-08, the 2005 and 2007 ArcticNet cruises, and finally the Nansen Amundsen Basin Observing System cruise in 2007. These cruises sampled the major coastal regions surrounding the Arctic central basin: the eastern Beaufort Sea, the northern Baffin Bay, the Canadian archipelago, and the Laptev Sea. The presentation will describe the spatial and temporal variability of aph and evaluate its similitude with the database covering the southern waters. (Au)

H
Chlorophyll; Light; Optical properties; Phytoplankton; Plant distribution; Suspended solids; Temporal variations

G07, G0815, G09, G141
Baffin Bay-Davis Strait; Canadian Arctic Islands waters; Canadian Beaufort Sea; Laptevykh More


Seasonal variability of phytoplankton chlorophyll a specific light absorption coefficient in the Amundsen Gulf   /   Brunelle, C.B.   Larouche, P.P.L.
In: Circumpolar Flaw Lead System Study, International Polar Year, 2007-2008 : meeting materials, CFL All-Hands Meeting, 1-5 November 2009, Winnipeg / University of Manitoba. - [Winnipeg, Man.] : University of Manitoba, 2009, p. 18
Abstract of a poster presentation.
ASTIS record 69696.
Languages: English
Libraries: ACU

Differences in cell size and pigment composition are assumed to be the main factors affecting the way that light is absorbed by phytoplankton (Kirk, 1994). At polar latitudes, extreme living conditions could induce adaptations in cell physiology or acclimations in cell processes. That may in turn affect the phytoplankton light absorption spectrum in polar environments and induce a bias in remote sensing or bio-optic models. We report here on a project to study the phytoplankton chlorophyll a specific absorption coefficient a(phi)*(lambda). Data was acquired during the ArcticNet program (September-October 2007), during the CFL project (March-July 2008) and during the CASES project (September-October 2003 and June-August 2004) in the Amundsen Gulf region (71°N; 126°W) that is characterized by the presence of a polynya. Coefficients were measured using the Transmittance-Reflectance method (Tassan and Ferrari, 2002) with methanol (100%) extraction. High Performance Liquid Chromatography (HPLC) analyses have also been made on samples (Zapata, 2001) to determine the concentrations of major phytoplankton pigments and species. The presentation will focus on the seasonal variation of the a(phi)*(lambda) coefficient and its relations to the evolving phytoplankton community and the main physical forcing factors. (Au)

H, D
Biological sampling; Chlorophyll; Chromatography; Light; Optical properties; Phytoplankton; Plant distribution; Sea water; Seasonal variations; Size

G0815
Amundsen Gulf, N.W.T.


Evaluation and improvement of the PIEKTUK blowing snow model on the Canadian Prairies and Arctic   /   Butler, J.E.   Hanesiak, J. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2008.
xiv, 101 p. : ill., map ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR48956)
ISBN 978-0-494-48956-7
Appendices.
References.
Thesis (M.Sc.) - University of Manitoba, Winnipeg, Man., 2008.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74965.
Languages: English
Web: http://www.collectionscanada.gc.ca/obj/thesescanada/vol2/002/MR48956.PDF
Libraries: OONL

Blowing snow is an important part of Canadian's lives. Accurate forecasting of blowing snow events and their visibility can be an important factor for the safety of Canadians. The PIEKTUK blowing snow model can be used to predict the occurrence of blowing snow, and to predict the visibility during an event. During an initial analysis, the model appeared to predict the occurrence of blowing snow very accurately, but once null weather events were removed, the model over-predicted more events than it correctly forecast. In an attempt to improve the forecasting capabilities of the model, the calculation for the threshold wind speed was tested by increasing and decreasing the constant coefficient in the equation incrementally to see if another value was optimal. For most stations, increasing the constant by 1 to 5 improved the forecasting of blowing snow events over the original version. More consistent improvements were found in Prairie and Arctic regions than in Forest or Mountain regions. The influence of wind direction was also added into the model, and the results were analyzed for one Prairie station and one Arctic station. Minimal improvement was observed for Winnipeg, and none for Baker Lake. The predictions made by PIEKTUK were also compared to data recorded during the CASES project. Unlike earlier conclusions, decreasing the constant by -2 was found to improve the model the most due to the smooth nature of the surface (snow covered first-year sea ice). (Au)

F, E, H, A, G
Atmospheric humidity; Atmospheric pressure; Atmospheric temperature; Blowing snow; Mathematical models; Plant distribution; Sea ice; Surface properties; Theses; Topography; Trees; Velocity; Visibility; Weather forecasting; Weather stations; Winds

G0813, G0812, G0824, G0823, G0822, G081, G08, G0815
Baker Lake (Hamlet), Nunavut; Canadian Arctic; Edmonton, Alberta; Fort Simpson, N.W.T.; Fort Smith, N.W.T.; Franklin Bay, N.W.T.; Prairie Provinces; Red Deer, Alberta; Resolute, Nunavut; Saskatoon, Saskatchewan; Winnipeg, Manitoba


Modelling the effects of climate change on mercury dynamics in the Beaufort Sea   /   Cadieux, M.A.   Stern, G.A.   Hickie, B.E.   Dastoor, A.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 193-194
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67118.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

High mercury concentrations are consistently reported in Arctic marine mammals and are increasing temporally. Not only does this represent a threat to the health of the animals, but it also represents a danger to native communities that consume them as part of their traditional diets. Recently, the first mass balance inventory for mercury was developed for the Arctic which suggested increases in total mercury inputs to the Arctic were considerably lower than increases in fish and marine mammals observed over the same time scale. Research has suggested that climate change might be modifying the factors governing the uptake and transfer efficiency of mercury in food webs and that current mercury fluxes from inputs and losses are likely to change considerably in a warming Arctic. The overall objective of this study is to expand the usefulness of mass balance inventories by constructing a predictive dynamic model for mercury in the Beaufort Sea, where warming is predicted to have the most dramatic effect. Defining an assortment of climate change scenarios such as reduced ice cover, increased nutrient availability, and food-web regime shifts, this model will link abiotic and biotic systems and predict mercury concentrations at several environmental levels (e.g. water column, ice pack, marine mammals). Atmospheric fluxes will be derived by coupling the Global\Regional Atmospheric Heavy Metals (GRAHM) model to our model. Calibration will be achieved by drawing on the vast data sets collected by the "ArcticNet" network. Additional data will be collected onboard the CCGS Amundsen or in the Mackenzie Delta region if knowledge gaps are identified. The model is currently in early development, and due to the large scope of the study, considerable dialogue with experts in several fields is necessary to continue logical and factual development. (Au)

J, D, G, E, I
Atmospheric circulation; Climate change; Environmental impacts; Fishes; Food chain; Ice cover; Marine mammals; Mass balance; Mathematical models; Melting; Mercury; Pollution; Sea ice; Sea water

G07
Canadian Beaufort Sea


Climate variability and physical forcing of the food webs and the carbon budget on panarctic shelves   /   Carmack, E.   Barber, D.   Christensen, J.   Macdonald, R.   Rudels, B.   Sakshaug, E.
(Structure and function of contemporary food webs on Arctic shelves : a pan-Arctic comparison / Edited by Paul Wassmann. Progress in oceanography, v. 71, no. 2-4, Oct.-Dec. 2006, p. 145-181, ill., maps)
References.
ASTIS record 63253.
Languages: English
Web: doi:10.1016/j.pocean.2006.10.005
Libraries: ACU

Brief overviews of the Arctic's atmosphere, ice cover, circulation, primary production and sediment regime are given to provide a conceptual framework for considering panarctic shelves under scenarios of climate variability. We draw on past 'regional' studies to scale-up to the panarctic perspective. Within each discipline a synthesis of salient distributions and processes is given, and then functions are noted that are critically poised at/or near transition and thereby sensitive to climate variability and change. The various shelf regions are described and distinguished among three types: inflow shelves, interior shelves and outflow shelves. Emphasis is on projected climate changes that will likely have the greatest impact on shelf-basin exchange, productivity and sediment processes including (a) changes in wind fields (e.g. currents, ice drift, upwelling and downwelling); (b) changes in sea ice distribution (e.g. radiation and wind regimes, enhanced upwelling and mixing, ice transport and scour resuspension, primary production); and (c) changes in hydrology (e.g. sediment and organic carbon delivery, nutrient supplies). A discussion is given of the key rate-controlling processes, which differ for different properties and shelf types, as do the likely responses; that is, the distributions of nutrients, organic carbon, freshwater, sediments, and trace minerals will all respond differently to climate forcing. A fundamental conclusion is that the changes associated with light, nutrients, productivity and ice cover likely will be greatest at the shelf-break and margins, and that this forms a natural focus for a coordinated international effort. Recognizing that the real value of climate research is to prepare society for possible futures, and that such research must be based both on an understanding of the past (e.g. the palaeo-record) as well as an ability to reliably predict future scenarios (e.g. validated models), two recommendations emerge: firstly, a comprehensive survey of circumpolar shelf-break and slope sediments would provide long-term synchronous records of shelf-interior ocean exchange and primary production at the shelf edge; secondly, a synoptic panarctic ice and ocean survey using heavy icebreakers, aircraft, moorings and satellites would provide the validation data and knowledge required to properly model key forcing processes at the margins. (Au)

A, B, D, G, F, E, J, A
Animal distribution; Animal food; Atmospheric temperature; Bathymetry; Beach erosion; Benthos; Biological productivity; Biomass; Bottom sediments; Carbon; Carbon cycling; Chemical oceanography; Climate change; Continental shelves; Current scouring; Environmental impacts; Estuaries; Estuarine ecology; Food chain; Geochemistry; Hydrology; Ice cover; Ice scouring; Light; Marine ecology; Marine fauna; Mass balance; Mathematical models; Melting; Ocean currents; Ocean floors; Ocean temperature; Ocean-atmosphere interaction; Oceanography; Palaeogeography; Phytoplankton; Plant distribution; Polynyas; Primary production (Biology); River discharges; Rivers; Salinity; Sea ice; Sea ice ecology; Sea level; Seasonal variations; Sedimentation; Snow cover; Surface temperature; Suspended solids; Temporal variations; Thickness; Water masses; Winds; Zooplankton

G03, G02, G0812, G05, G11, G07
Amundsen Gulf, N.W.T.; Arctic Ocean; Arctic waters; Barents Sea; Beaufort Sea; Bering Sea; Canadian Arctic Islands waters; Canadian Beaufort Sea; Chukchi Sea; East Greenland Current; Fram Strait; Greenland Sea; Labrador Sea; Mackenzie River, N.W.T.; North Atlantic Ocean; North Pacific Ocean; North Water Polynya, Baffin Bay; Northeast Water Polynya, Greenland Sea; Norwegian Sea; Russian Arctic waters; Spitsbergen waters, Svalbard


Evidence that viral abundance across oceans and lakes is driven by different biological factors   /   Clasen, J.L.   Brigden, S.M.   Payet, J.P.   Suttle, C.A.
(Freshwater biology, v. 53, no. 6, June 2008, p.1090-1100, ill., map)
References.
ASTIS record 65289.
Languages: English
Web: doi:10.1111/j.1365-2427.2008.01992.x
Libraries: ACU

1. Samples from 16 lakes in central (n=145) and western (n=12) North America, the coastal northeast Pacific (n=302) and the western Canadian Arctic Oceans (n=142) were collected and analysed for viral, bacterial and cyanobacterial abundances and chlorophyll-a concentration. 2. Viral abundance was significantly different among the environments. It was highest in the coastal Pacific Ocean and lowest in the coastal Arctic Ocean. The abundances of bacteria and cyanobacteria as well as chlorophyll-a concentrations also differed significantly among the environments, with both bacterial abundance and chlorophyll-a concentration highest in lakes. As a consequence, the association of these variables with viral abundance varied among the environments. 3. Discriminant analyses with the abundance data indicated that the marine and freshwater environments were predictably different from each other. Multiple-regression analysis included bacterial and cyanobacterial abundances, and chlorophyll-a concentration as significant variables in explaining viral abundance in lakes. In regression models for the coastal Pacific Ocean, bacterial and cyanobacterial abundances were significant variables, and for the coastal Arctic Ocean viral abundance was predicted by bacterial abundance and chlorophyll-a concentration. 4. The relationship of viral and bacterial abundance differed between the investigated freshwater and marine environments, probably because of differences in viral production and loss rates. However, freshwaters had fewer viruses compared to bacteria, despite previously documented higher burst sizes and frequencies of infected cells, suggesting that loss rates may be more important in lakes. 5. Together, these findings suggest that there are different drivers of viral abundance in different aquatic environments, including lakes and oceans. (Au)

H, J, F, D
Bacteria; Chlorophyll; Cyanophyceae; Fluorometry; Fresh-water ecology; Lakes; Marine ecology; Microbial ecology; Plant distribution; Viruses

G07, G0821, G05, G0825
British Columbia; Canadian Beaufort Sea; Ontario; Vancouver Island waters, British Columbia


Microbial communities at very low temperatures in natural saline ice formations   /   Collin, R.E.   Carpenter, S.D.   Deming, J.W.
(Astrobiology, v. 5, no. 2, 2005, p. 252)
Abstract only.
This issue contains abstracts from NAI 2005, the biennial meeting of the NASA Astrobiology Institute which was hosted by the University of Colorado, Boulder, April 10-14, 2005.
Abstract #1058 in Session 5: Evolution of Life.
R. Eric Collins name is misspelled R. Eric Collin.
ASTIS record 74781.
Languages: English
Web: doi:10.1089/ast.2005.5.241
Libraries: ACU

The majority of our solar system exists in a state of perennial cold, but there are few locations and opportunities to study life on Earth at particularly extreme temperatures. The coldest habitat on Earth in which a significant fraction of liquid water persists is wintertime sea ice (where the eutectic lies below -35°C). We studied Arctic sea ice during the coldest months of the year (January through March) to determine if the encased microbial communities react to similar environmental stresses (i.e., high salinity, low temperature) by altering community composition in similar ways. Of three depth horizons in the ice (centered at 25-, 45-, and 65-cm below surface), total microbial abundance (as measured by DAPI staining) did not change significantly in two of the horizons, even as the temperature of each ice horizon decreased an average of 18°C (to a minimum measured in situ temperature of -28°C) over the course of about 10 weeks. Detection of a change in community composition in these sections would indicate growth by selected members of the community under the extreme conditions of the ice. We have begun direct measurements of community composition in the ice from these horizons using terminal-restriction fragment length polymorphism (T-RFLP) analysis, to learn whether the community composition was static or dynamic during the winter season. We expect to observe a decrease in diversity as the more extreme conditions developed and provided selective pressure against common seawater microorganisms in favor of those adapted to life at high salinity and low temperature. (Au)

H, I, J, G
Cores; Genetics; Microbial ecology; Microorganisms; Salinity; Sea ice; Sea ice ecology; Spatial distribution; Temperature

G0815
Franklin Bay, N.W.T.


REPK : an analytical web server to select restriction endonucleases for terminal restriction fragment length polymorphism analysis   /   Collins, R.E.   Rocap, G.
(Nucleic acids research, v. 35, suppl. 2, July 2007, p. W58-W62)
References.
ASTIS record 74715.
Languages: English
Web: doi:10.1093/nar/gkm384
Libraries: ACU

Terminal restriction fragment length polymorphism (T-RFLP) analysis is a widespread technique for rapidly fingerprinting microbial communities. Users of T-RFLP frequently overlook the resolving power of well-chosen restriction endonucleases and often fail to report how they chose their enzymes. REPK (Restriction Endonuclease Picker) assists in the rational choice of restriction endonucleases for T-RFLP by finding sets of four restriction endonucleases that together uniquely differentiate user-designated sequence groups. With REPK, users can provide their own sequences (of any gene, not just 16S rRNA), specify the taxonomic rank of interest and choose from a number of filtering options to further narrow down the enzyme selection. Bug tracking is provided, and the source code is open and accessible under the GNU Public License v.2, at http://code.google.com/p/repk. The web server is available without access restrictions at http://rocaplab.ocean.washington.edu/tools/repk. (Au)

H, I, J, Y
Animal taxonomy; Bacteria; Electronic data processing; Enzymes; Genetics; Identification; Logistics; Measurement; Microorganisms; Plant taxonomy; World Wide Web

G16


Spatial heterogeneity and temporal dynamics of particles, bacteria, and pEPS in Arctic winter sea ice   /   Collins, R.E.   Carpenter, S.D.   Deming, J.W.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 902-917, ill., maps)
References.
ASTIS record 65271.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.09.005
Libraries: ACU

Abundances of particles, total bacteria, and particulate extracellular polymeric substances (pEPS) in Arctic sea ice were tracked through a winter season to examine the impact of combined extremes of low temperature and high salinity on the prokaryotic microbial community. Three horizons, centered at depths of 25, 45, and 65 cm from the ice surface, with mean seasonal temperatures of -20, -17, and -13 °C, respectively, were sampled 16 times over the course of 12 weeks. Microscopic counts of bacteria (stained with DAPI) and particles (stained with acridine orange) reflected the dynamic conditions of the growing ice sheet, with greater abundances and variability in the upper ice horizons compared to the lower. The trend of higher particle and bacterial abundances in the upper ice was corroborated by several full-depth profiles taken during the expedition, which also displayed significantly decreasing cell abundance with depth. Bacterial abundance declined slowly and significantly with time in the upper and middle ice horizons, but not in the lowest, suggesting that much of the prokaryotic microbial community is resilient to extreme environmental conditions. We found that pEPS concentrations increased significantly with time and with decreasing temperatures in all depth horizons, which may lend support to the argument that sea ice bacteria produce EPS in situ as a cryoprotectant. (Au)

H, J, G, D, E
Atmospheric temperature; Bacteria; Carbohydrates; Cold adaptation; Cores; Formation; Growth; Microbial ecology; Ocean temperature; Psychrophilic bacteria; Salinity; Sea ice; Sea ice ecology; Size; Spatial distribution; Sugars; Suspended solids; Temporal variations; Thickness

G0815, G0812
Franklin Bay, N.W.T.; Horton River, N.W.T.


Persistence of bacterial and archaeal communities in sea ice through an Arctic winter   /   Collins, R.E.   Rocap, G.   Deming, J.W.
(Environmental microbiology, v. 12, no. 7, July 2010, p.1828-1841, ill.)
References.
Supporting information available online.
ASTIS record 74778.
Languages: English
Web: doi:10.1111/j.1462-2920.2010.02179.x
Libraries: ACU

The structure of bacterial communities in first-year spring and summer sea ice differs from that in source seawaters, suggesting selection during ice formation in autumn or taxon-specific mortality in the ice during winter. We tested these hypotheses by weekly sampling (January-March 2004) of first-year winter sea ice (Franklin Bay, Western Arctic) that experienced temperatures from -9°C to -26°C, generating community fingerprints and clone libraries for Bacteria and Archaea. Despite severe conditions and significant decreases in microbial abundance, no significant changes in richness or community structure were detected in the ice. Communities of Bacteria and Archaea in the ice, as in under-ice seawater, were dominated by SAR11 clade Alphaproteobacteria and Marine Group I Crenarchaeota, neither of which is known from later season sea ice. The bacterial ice library contained clones of Gammaproteobacteria from oligotrophic seawater clades (e.g. OM60, OM182) but no clones from gammaproteobacterial genera commonly detected in later season sea ice by similar methods (e.g. Colwellia, Psychrobacter). The only common sea ice bacterial genus detected in winter ice was Polaribacter. Overall, selection during ice formation and mortality during winter appear to play minor roles in the process of microbial succession that leads to distinctive spring and summer sea ice communities. (Au)

H, I, J, G, D
Archaea; Bacteria; Cores; Formation; Genetics; Marine ecology; Microbial ecology; Plant collections; Plant distribution; Plant taxonomy; Psychrophilic bacteria; Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Spatial distribution; Temperature

G0815
Franklin Bay, N.W.T.


Arctic Ocean microbial community structure before and after the 2007 record sea ice minimum   /   Comeau, A.M.   Li, W.K.W.   Tremblay, J.-É.   Carmack, E.C.   Lovejoy, C.
(PloS one, v. 6, no. 11, e27492, Nov. 2011, 12 p., ill., map)
References.
Supporting information available online.
ASTIS record 74927.
Languages: English
Web: doi:10.1371/journal.pone.0027492

Increasing global temperatures are having a profound impact in the Arctic, including the dramatic loss of multiyear sea ice in 2007 that has continued to the present. The majority of life in the Arctic is microbial and the consequences of climate-mediated changes on microbial marine food webs, which are responsible for biogeochemical cycling and support higher trophic levels, are unknown. We examined microbial communities over time by using high-throughput sequencing of microbial DNA collected between 2003 and 2010 from the subsurface chlorophyll maximum (SCM) layer of the Beaufort Sea (Canadian Arctic). We found that overall this layer has freshened and concentrations of nitrate, the limiting nutrient for photosynthetic production in Arctic seas, have decreased. We compared microbial communities from before and after the record September 2007 sea ice minimum and detected significant differences in communities from all three domains of life. In particular, there were significant changes in species composition of Eukarya, with ciliates becoming more common and heterotrophic marine stramenopiles (MASTs) accounting for a smaller proportion of sequences retrieved after 2007. Within the Archaea, Marine Group I Thaumarchaeota, which earlier represented up to 60% of the Archaea sequences in this layer, have declined to <10%. Bacterial communities overall were less diverse after 2007, with a significant decrease of the Bacteroidetes. These significant shifts suggest that the microbial food webs are sensitive to physical oceanographic changes such as those occurring in the Canadian Arctic over the past decade. (Au)

I, H, D, J, E, G
Animal distribution; Animal taxonomy; Archaea; Bacteria; Biological sampling; Carbon cycling; Chemical oceanography; Chlorophyll; Climate change; Electrical properties; Environmental impacts; Fluorometry; Food chain; Genetics; Marine ecology; Melting; Microbial ecology; Nitrogen oxides; Ocean temperature; Ocean-atmosphere interaction; Photosynthesis; Plant distribution; Plant taxonomy; Primary production (Biology); Sea ice; Sea water; Seasonal variations; Solar radiation; Temporal variations; Trophic levels; Water masses

G03, G07, G0815
Amundsen Gulf, N.W.T.; Arctic Ocean; Canada Basin, Arctic Ocean; Canadian Beaufort Sea


Distribution patterns of Canadian Beaufort Shelf macrobenthos   /   Conlan, K.   Aitken, A.   Hendrycks, E.   McClelland, C.   Melling, H.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 864-886, ill., maps)
Appendix.
References.
ASTIS record 65266.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.10.002
Libraries: ACU

Variation in macrofaunal composition in relation to sediment and water variables was analysed in nine regions of the western Canadian Arctic on the Beaufort Shelf and in Amundsen Gulf. We hypothesized that benthic community composition was distinctive (1) in a recurrent polynya in Amundsen Gulf and (2) in upwelling regions (Cape Bathurst and Mackenzie Canyon) and (3) changed in a linear gradient across the Beaufort Shelf. Analysis was based on 497 taxa >0.4 mm from 134 samples at 52 stations sampled over 2002-4 in 11-1000 m water depth. Abundance ranged from 490.7/m² in eastern Amundsen Gulf to 17,950/m² off Cape Bathurst. (1) Community composition in Amundsen Gulf was not significantly different from the Beaufort Shelf at similar depth, indicating a lack of benthic effect of the polynya in Amundsen Gulf. (2) The Mackenzie Canyon macrofauna, although abundant and diverse, were similarly indistinct from the shelf community at similar depth. However, there was a 10-fold increase in inshore abundance in the upwelling region of Cape Bathurst due to large numbers of the amphipod Ampelisca macrocephala and the polychaete Barantolla americana, species that were not abundant elsewhere. (3) In the inshore fast ice and flaw lead regions of the Beaufort Shelf, under the influence of ice scour, storm effects, coastal erosion and the Mackenzie River, the macrofauna were dominated by the bivalve Portlandia arctica and the polychaete Micronephthys minuta. Offshore, where these influences were less and upwelling of deep Atlantic water occurred, the polychaete Maldane sarsi dominated. Faunal distribution across the Beaufort Shelf correlated with depth, water and sediment changes but was not significantly linear. (Au)

I, G, D, F, A
Amphipoda; Animal distribution; Animal food; Animal population; Benthos; Bottom sediments; Carbon; Continental shelves; Cores; Crustacea; Echinoderms; Erosion; Fast ice; Ice cover; Ice leads; Ice scouring; Isopoda; Isotopes; Mollusks; Nitrogen; Ocean currents; Ocean temperature; Ostracoda; Oxygen; Polychaeta; Polynyas; River discharges; Salinity; Velocity; Water masses; Wildlife habitat

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Biogeochemistry of benthic boundary layer zooplankton and particulate organic matter on the Beaufort Sea shelf   /   Connelly, T.L.   Deibel, D. [Supervisor]
St. John's, Nfld. : Memorial University of Newfoundland, 2008.
xiii, 170 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR55370)
ISBN 978-0-494-55370-1
References.
Thesis (Ph.D.) - Memorial University of Newfoundland, St. John's, Nfld., 2008.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74966.
Languages: English
Web: http://www.collectionscanada.gc.ca/obj/thesescanada/vol2/002/NR55370.PDF
Libraries: OONL

Food webs of benthic boundary layer zooplankton and the biogeochemistry of near-bottom water on the Beaufort Sea shelf were studied during fall 2003 and summer 2004. The influence of the Mackenzie River on the source, quantity, and quality of organic matter in near-bottom waters across the Beaufort Sea shelf was investigated by integrating chlorophyll, fatty acid, C, N, and P concentration and ratio, and delta 13C data of particulate organic matter (POM). The Mackenzie River had a strong influence on the composition of POM in near-bottom waters across the entire Beaufort Sea shelf, including the Amundsen Gulf, with terrestrial markers, such as POM concentrations, fatty acid signatures and delta 13C values, strongest near the river. An enhanced microbial fingerprint on near-bottom waters near the river was also observed based on C:N ratios and bacterial fatty acid signatures. Fatty acids allowed detection of a phytoplankton sinking event during summer that would not have been apparent using only C:N ratios and chlorophyll a. In addition, elemental composition (C, N, and P content and stoichiometry), lipid classes, fatty acids, and stable isotope ratios (delta 13C and delta 15N) were used to study the diets and energy storage of 26 taxa of benthic boundary layer zooplankton. This is the first report of the biochemical composition and trophic ecology of many of the amphipods and mysids presented here. Almost all taxa had high levels of wax esters or triacylglycerol, suggesting that benthic boundary layer zooplankton on the Beaufort Sea shelf are directly linked to intense seasonal pulses of primary production characteristic of high latitude seas. delta 15N and fatty acid signatures indicate that there were diverse feeding modes among the taxa with trophic levels ranging from 2-4. Fatty acid profiles not only reflected diet but also phylogeny, with taxa of malacostracan crustaceans having similar fatty acid profiles. Phytoplankton fatty acid markers in copepods and chaetognaths indicate that the conventional, phytoplankton-copepod-chaetognath food web was also present in the benthic boundary layer. Using multiple biomarkers and tracers allowed for increased understanding of zooplankton feeding ecology and the sources of organic matter in near-bottom waters. (Au)

I, H, J, D, F, B
Amphipoda; Animal ecology; Animal food; Bacteria; Benthos; Biological sampling; Bottom sediments; Carbon ; Carbon cycling; Chaetognatha ; Chlorophyll; Copepoda; Crustacea; Decapoda; Diatoms; Echinoderms; Euphausiacea; Fatty acids; Food chain; Isotopes; Lipids; Marine ecology; Mysidacea ; Nitrogen; Ocean temperature; Particulate organic matter; Phosphorus; Phytoplankton; Polychaeta; River discharges; Salinity; Seasonal variations; Sedimentation; Shrimp; Spatial distribution; Suspended solids; Theses; Trophic levels; Water masses; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Kugmallit Bay, N.W.T.; Mackenzie Bay, N.W.T./Yukon


Biodiversity of benthic assemblages on the Arctic continental shelf : historical data from Canada   /   Cusson, M.   Archambault, P.   Aitken, A.
(Marine ecology. Progress series (Halstenbek), v.331, Feb. 16, 2007, p. 291-304, ill., maps)
References.
ASTIS record 63255.
Languages: English
Web: http://www.int-res.com/abstracts/meps/v331/p291-304/
Web: doi:10.3354/meps331291
Libraries: AEU

This study describes patterns of abundance, diversity, and assemblages of benthic macrofauna within the Canadian Arctic Archipelago. A review of data reports and the published literature yielded 219 stations and 947 taxa from 7 sources in various regions of the Canadian Arctic Archipelago (i.e. Beaufort Sea and Mackenzie Shelf, Victoria Island, Hudson and James Bays, Frobisher Bay, Ungava Bay, and Southern Davis Strait). In general, we observed that eastern regions of the Canadian Arctic Archipelago showed greater values of species richness (or diversity) than the western and central regions, whereas no specific patterns were observed for Shannon-Wiener’s diversity (H') and Pielou’s evenness (J') indices. The Beaufort Sea and Mackenzie Shelf region exhibited high values of taxonomic distinctness (Delta+), whereas Hudson Bay showed low values. However, the Hudson Bay region showed high values of turnover (ßw) diversity. A non-metric multi-dimensional scaling plot of similarity (Bray-Curtis index) and analysis of similarity revealed that species composition differed among regions, even those located in close proximity to one another. These investigations were conducted at different levels of taxonomic resolution (Species, Order, Class and Phyla) and the results demonstrated that most patterns were maintained up to the Order and Class level. A relatively small number of taxa, mainly annelids, were responsible for most of the dissimilarity among regions. Bottom salinity and temperature were the most important environmental variables (among depth of site, bottom temperature, salinity, physical and chemical sediment characteristics) for determining these assemblage patterns. Multiple regression analyses also demonstrated that variance in species richness and diversity (H') was best explained by variance in salinity (55 and 43% respectively). The analysis of a time series from Frobisher Bay revealed that the temporal (mo/yr-scale) variability of assemblages was of the same order as the spatial (km-scale) variability among sites. (Au)

I, D, J, B, V
Animal distribution; Animal population; Animal taxonomy; Bathymetry; Benthos; Bibliographic databases; Biology; Bottom sediments; Chemical oceanography; Continental shelves; Deglaciation; Geochemistry; History; Marine ecology; Marine fauna; Measurement; Numeric databases; Ocean temperature; Oceanography; Primary production (Biology); Research; Salinity; Sea level; Spatial distribution; Temporal variations

G07, G0815, G0814, G0812, G0826
Baffin Bay-Davis Strait; Canadian Arctic Islands waters; Canadian Beaufort Sea; Frobisher Bay, Nunavut; Grande Rivière, La, Québec; Hudson Bay; James Bay; Mackenzie River, N.W.T.; Ungava, Baie d', Québec; Victoria Island waters, N.W.T./Nunavut


Timing of reproductive events in the marine copepod Calanus glacialis : a pan-Arctic perspective   /   Daase, M.   Falk-Petersen, S.   Varpe, Ø.   Darnis, G.   Søreide, J.E.   Wold, A.   Leu, E.   Berge, J.   Philippe, B.   Fortier, L.
(Canadian journal of fisheries and aquatic sciences, v. 70, no. 6, June 2013, p. 871-884, ill., maps)
References.
ASTIS record 77662.
Languages: English
Web: doi:10.1139/cjfas-2012-0401
Libraries: ACU

The timing of reproductive events of C. glacialis is closely coupled to the two major marine primary production events in the Arctic: the ice algal and phytoplankton blooms. Reproductive strategies vary between different physical and biological environments of the European and Canadian Arctic. In the Canadian Beaufort Sea and the high Arctic Rijpfjorden on Svalbard, C. glacialis utilized the ice algae bloom to fuel spawning in spring, while growth and development of the new generation was primarily supported by the phytoplankton bloom. In the predominantly ice free Arctic Kongsfjorden (Svalbard), C. glacialis was mainly a capital breeder spawning early in the season in the absence of food. This enabled the offspring to synchronize their growth and development with the phytoplankton bloom and, thus, reproduce successfully despite the lack of an early ice algal bloom. The variability in life history traits observed in the Canadian and European Arctic is compared with data from other Arctic regions to present a pan-Arctic perspective on life cycle strategies of C. glacialis. (Au)

I, H, J, G, D
Algae; Animal distribution; Animal ecology; Animal food; Animal growth; Animal reproduction; Biological sampling; Biomass; Breakup; Carbon; Chlorophyll; Copepoda; Cores; Diatoms; Ice cover; Ice leads; Invertebrate eggs; Lipids; Marine ecology; Melting; Nitrogen; Ocean temperature; Phytoplankton; Polynyas; Primary production (Biology); Salinity; Sea ice; Sea ice ecology; Seasonal variations; Temporal variations; Thickness; Zooplankton

G0815, G12, G07, G02
Amundsen Gulf, N.W.T.; Arctic waters; Franklin Bay, N.W.T.; Kongsfjorden, Svalbard; Rijpfjorden, Svalbard


Structure de la communauté de zooplancton du plateau du Mackenzie (mer de Beaufort)   /   Darnis, G.   Fortier, L. [Supervisor]
Québec, Québec : Université Laval, 2007.
x, 65 p. : ill., maps ; 28 cm..
Thesis (M.Sc.) - Université Laval, Québec, Québec , 2007.
References.
General introduction and general conclusion in French; remaining chapters in English.
ASTIS record 74969.
Languages: English or French
Web: http://archimede.bibl.ulaval.ca/archimede/meta/24258
Libraries: OONL QQLAS

The objective of my study was to describe the biogeography of the zooplankton in the southeastern Beaufort Sea in the fall 2002 by means of multivariate and indicator species analysis. A neritic community characterized by herbivory and the dominant taxon Pseudocalanus spp., occurred on the Mackenzie shelf and in Franklin Bay. Two oceanic communities, in which omnivore and carnivore feeding modes dominated, were located in the Amundsen Gulf Polynya and over the continental slope respectively. The polynya assemblage displayed the highest biomass with the dominant species Calanus hyperboreus, Metridia longa, Oithona similis, and Oncaea borealis as indicator species. This repartition of zooplankton assemblages was influenced mostly by the topography and the ice cover dynamic during the season of high biological production. Hence, it is predicted that a reduction in ice cover, as anticipated in the present context of global warming, will alter the distribution patterns of zooplankton, a key element of the marine ecosystem in the Arctic. (Au)

I, D, E, J, G, H
Animal distribution; Bioclimatology; Biomass; Climate change; Continental shelves; Hydrography; Ice cover; Marine ecology; Phytoplankton; Polynyas; Sea ice ecology; Submarine topography; Theses; Trophic levels; Zooplankton

G07, G0815
Bathurst, Cape, N.W.T.; Franklin Bay, N.W.T.; Kugmallit Valley, Canadian Beaufort Sea


Sea ice and the onshore-offshore gradient in pre-winter zooplankton assemblages in southeastern Beaufort Sea   /   Darnis, G.   Barber, D.G.   Fortier, L.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 994-1011, ill., maps)
References.
ASTIS record 65272.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.09.003
Libraries: ACU

Zooplankton communities were studied in southeastern Beaufort Sea (Arctic Ocean) in September-October 2002. Cluster analysis and non-metric multidimensional scaling revealed three distinct mesozooplankton assemblages. A neritic assemblage occurred on the Mackenzie Shelf and in Franklin Bay, while distinct off-shelf assemblages prevailed in the Cape Bathurst Polynya and on the Beaufort Slope respectively. Over 95% of the mesozooplankton was comprised of eight copepod taxa. Pseudocalanus spp. contributed predominantly to the discrimination of the three assemblages and was the only significant indicator of the Shelf assemblage. Oithona similis, Oncaea borealis, Metridia longa and Calanus hyperboreus were indicators of the Polynya assemblage. Cyclopina sp. and Microcalanus pygmaeus were indicative of the overall off-shelf community (Polynya and Slope assemblages). The importance of omnivores and carnivores increased from the shelf to the polynya and the slope. Station depth and duration of reduced ice conditions during summer (<50% ice concentration) underpinned the distribution of the assemblages (r²=0.71 and 0.45 respectively). The abundance of Pseudocalanus spp. was independent of depth and increased with the duration of reduced ice conditions (rs=0.438). The abundance of Cyclopina sp., M. pygmaeus and other indicators of the offshore assemblages followed the opposite trend (rs=-0.467 and -0.5 respectively). Under continued climate warming, a reduction of the ice cover will affect the biogeography of mesozooplankton on and around the Mackenzie Shelf, to the potential advantage of Pseudocalanus spp. and other calanoid herbivores. (Au)

I, G, D, J, E, A
Animal distribution; Animal population; Bathymetry; Biomass; Chlorophyll; Climate change; Continental shelves; Copepoda; Environmental impacts; Fast ice; Fluorometry; Ice cover; Ocean temperature; Pack ice; Polynyas; Salinity; Sea ice; Sea water; Trophic levels; Water masses; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Kugmallit Bay, N.W.T.


Dinocysts as tracers of sea-surface conditions and sea-ice cover in polar and subpolar environments   /   de Vernal, A.   Rochon, A.
(IODP-Canada Summer School on 'Ocean and Climate Changes in Polar and Subpolar Environments', 27 June-12 July 2010, Rimouski, Quebec, Montreal, Canada / Edited by G. St-Onge, C. Veiga-Pires and S. Solignac. IOP conference series. Earth and environmental science, v. 14, no. 1, 2011, 12 p., ill., maps)
References.
ASTIS record 74779.
Languages: English
Web: doi:10.1088/1755-1315/14/1/012007
Libraries: ACU

Dinoflagellates are unicellular protists that produce a cyst (dinocyst) as part of their life cycle. The cyst wall of many species is composed of highly resistant organic matter. Dinocysts are thus routinely recovered in marine sediments and occur in high number along the continental margins of the world oceans notably in high latitude environments. They are widely used as proxy indicators of marine conditions and provide valuable information on the natural variability of climate, which in turn helps understanding and assessing the potential threat posed by the actual global warming. Here we present a brief outline of their biology, ecology and distribution in Arctic and subarctic areas. We also provide a few examples of paleoenvironmental reconstructions and briefly discuss on the significance of these results. (Au)

B, H, D, G, J
Bottom sediments; Climate change; Cores; Databases; Dinoflagellata; Environmental impacts; Ice cover; Microbial ecology; Ocean temperature; Palaeoecology; Palaeohydrology; Palynology; Palynomorphs; Plant anatomy; Plant distribution; Plant nutrition; Pleistocene epoch; Primary production (Biology); Recent epoch; Salinity; Sea ice; Seasonal variations; Sedimentation; Spatial distribution; Temporal variations

G02, G0815, G07
Arctic waters; Barrow Strait, Nunavut; Canadian Beaufort Sea; Dease Strait, Nunavut; Jones Sound, Nunavut; Lancaster Sound, Nunavut; Mackenzie Trough, Canadian Beaufort Sea


The role of appendicularians tunicates in the biogenic carbon cycle of three Arctic polynyas   /   Deibel, D.   Saunders, P.A.   Acuña, J.-L.   Bochdansky, A.B.   Shiga, N.   Rivkin, R.B.
In: Response of marine ecosystems to global change : ecological impact of appendicularians / Edited by G. Gorsky, M.J. Youngbluth, and D. Deibel. - Paris : Éditions Scientifique GB, 2005, p. 327-356, ill., maps
References.
ASTIS record 74712.
Languages: English
Libraries: QMM

Appendicularians have been well studied in tropical and temperate waters. They are also abundant in polar waters, where much less is known of their role in biogeochemical cycles. During the 1990s, we investigated individual and population ingestion rates of appendicularians in three arctic polynyas, the Northeast Water (NEW), the North Water (NOW) and the St. Lawrence Island Polynya (SLIP). In general, polynyas have higher annual primary and secondary productivity than do surrounding, ice-covered seas. Here we report a comparison of population structure and rates of herbivory by appendicularians in these polynyas. Appendicularians in the SLIP had the highest median abundance (21000/m²), biomass (2,200 mg C/m² and rates of population herbivory (280 mg C/m²/d), while these values in the NOW and NEW were one to several orders of magnitude lower. It is likely that these large populations in the SLIP were sustained by high primary productivity driven by upwelling Anadyr Water. Assuming that 50% of phytoplankton cells cleared from the water remain stuck within the house, appendicularians removed from suspension l0-20% of daily primary production. While appendicularian biomass was ca. 10% of copepod biomass in the two Greenland polynyas, it was 7-fold greater than copepod biomass in the SLIP. Furthermore, the estimated vertical flux of appendicularian fecal material was 35% of the trap-measured, vertical flux of biogenic carbon in the NOW, and nearly 100% in the SLIP and the NEW. Thus, failure to take appendicularians into account in models of polynya food webs will result in a significant underestimation of phytoplankton mortality and biogenic carbon export. Appendicularian populations require time to develop, with abundance peaks weeks to months after the polynyas open. Current global change scenarios hold that polynyas will open earlier, close later and become larger than at present, which should favour an increasing the annual contribution of appendicularians to biogenic carbon flux. (Au)

I, H, J, D, E
Animal distribution; Animal food; Animal population; Animal waste products; Appendicularians; Biological productivity; Biological sampling; Biomass; Carbon; Carbon cycling; Chlorophyll; Ciliata; Climate change; Copepoda; Diatoms; Dinoflagellata; Fluorometry; Food chain; Intestines; Marine biology; Microbial ecology; Ocean currents; Ocean temperature; Phytoplankton; Plant nutrition; Polynyas; Primary production (Biology); Salinity; Seasonal variations; Sedimentation; Size; Suspended solids; Water masses; Zooplankton

G09, G12, G04
North Water Polynya, Baffin Bay; Northeast Water Polynya, Greenland Sea; St. Lawrence Island waters, Alaska


Zooplankton processes in Arctic and Antarctic polynyas   /   Deibel, D.   Daly, K.L.
(Polynyas : windows to the world / Edited by W.O. Smith and D.G. Barber. Elsevier oceanography series, v. 74, 2007, ch. 9, p. 271-322, ill.)
References.
ASTIS record 63899.
Languages: English
Web: doi:10.1016/S0422-9894(06)74009-0
Libraries: ACU

There are various similarities and differences in zooplankton processes between Arctic Ocean (AO) and Southern Ocean (SO) polynyas, many of which are due to fundamental differences in their respective ecosystem properties. The composition of zooplankton communities in AO and SO polynyas is largely dependent upon advection from local, ice-covered waters, with little evidence of an endemic, polynya zooplankton fauna. While copepods are common in both systems, a major difference is the predominance of euphausiids in the SO and appendicularian tunicates in the AO. The same genera of small copepods occur in both the AO and SO and appear to derive little benefit from the higher primary productivity and extended growing season of polynyas. In contrast, larger calanoid copepods appear to derive recruitment and life cycle benefits from the diatom production and heat in polynyas, with higher egg production rates and shorter generation times. Most large calanoid copepods overwinter in diapause in AO polynyas, while some proportion of SO populations remain in surface waters. Grazing impact by copepods in AO polynyas accounts for about 20% of primary productivity/d, with appendicularian tunicates accounting for another 20%/d. The few estimates of community impact in the SO are variable. In both regions, individual zooplankton feeding rates are high and equivalent to boreal ocean values; thus, grazing impact depends primarily on the biomass of zooplankton and phytoplankton. SO zooplankton contribute to the vertical particulate flux through faecal pellets from euphausiids, copepods and pteropods, while the contribution in AO polynyas is primarily through appendicularian tunicate faecal pellets and shed houses and copepod faeces. Maximum pellet flux in both the AO and SO occurs at times of high biomass of diatoms. The primary benefits of polar polynyas to zooplankton processes results from the greater production of diatoms and extended productive period, with few differences in individual daily rations or food web transfer efficiencies relative to temperate and boreal systems. (Au)

J, I, H, G, D
Amphipoda; Animal distribution; Animal food; Animal population; Animal reproduction; Animal waste products; Appendicularia; Biological productivity; Biomass; Carbon; Chaetognatha ; Chlorophyll; Coelenterata; Copepoda; Ctenophora; Decapoda; Diatoms; Euphausiacea; Fatty acids; Food chain; Invertebrate larvae; Lipids; Mollusks; Nitrogen; Ostracoda; Phytoplankton; Polychaeta; Polynyas; Primary production (Biology); Seasonal variations; Sedimentation; Trophic levels; Tunicates; Zooplankton

G02, G15, G09, G0815, G03, G12
Antarctic waters; Arctic waters; Barrow Strait, Nunavut; Greenland Sea; Nansen Basin, Arctic Ocean; North Water Polynya, Baffin Bay; Prydz Bay, Antarctic regions; Weddell Sea, Antarctic regions


The pelagic food web : structure, function and contaminants   /   Deibel, D.   Fortier, L.   Stern, G.   Loseto, L.   Darnis, G.   Benoit, D.   Connelly, T.   Lafrance, P.   Seuthe, L.   Simard, Y.   Trela, P.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 6, p. 101-111, ill., map
References.
ASTIS record 67479.
Languages: English
Libraries: ACU

... The specific objectives of our group were to determine 1) the abundance, depth distribution and vertical migration of zooplankton, and juvenile and adult fish, 2) the predation rates of zooplankton herbivores and carnivores on their prey, 3) the respiration and egg production rates of copepods and appendicularians (two dominant zooplankton groups on the Beaufort Sea Shelf), 4) the predation, growth and survival rates of the early life stages of Arctic cod, 5) the detailed chemical composition of zooplankton and fish (i.e., the fats, fatty acids and stable isotopes which reflect information on their prey), and 6) the bioaccumulation and biomagnification of contaminants such as mercury and polychlorinated biphenyls (PCBs) within food webs. In order to achieve these objectives and fully comprehend the structure and function of food webs within the Beaufort Sea Shelf - an area which experiences pronounced seasonal changes in sea ice cover and river outflow - it was important to study biological dynamics over an entire year .... We used a wide variety of sampling devices and strategies to study zooplankton and fish on the Beaufort Sea Shelf .... We discovered an active food web under the ice during mid-winter and early spring in Franklin Bay .... Some of the copepod species within this web became active much earlier than was expected ... and there were remarkably high abundances of adult Arctic cod .... We documented a strong spatial variability in the productivity of food webs on the Beaufort Sea Shelf which appeared to depend primarily upon the timing of sea ice disappearance. ... Analysis of the species making up the zooplankton community over the study region indicated three different assemblages which were roughly associated with three distinct areas of depth and ice cover. ... These results demonstrate that the Beaufort Sea Shelf is a diverse region with a variety of food webs, and that it should not be managed as a single ecosystem of uniform food web structure and function. ... We discovered that Arctic cod hatched throughout late January to mid-July and exhibited maximum hatching rates between March and May. ... much of the hatching period occurred well before seasonal ice break-up and the subsequent warming of the surface layer and phytoplankton bloom. ... About 55% of the 2004 input of mercury (Hg) from the Mackenzie River to the Beaufort Sea occurred over a period of a few weeks in June during the spring freshet. ... This riverine input of contaminants was reflected in high mercury levels in Beaufort Sea Calanus ssp. and Arctic cod .... Mercury levels in beluga from the eastern area of the Beaufort Sea were among the highest reported in the Arctic Ocean .... During CASES, zooplankton and fish samples were collected for fatty acid, stable isotope and contaminants analyses, providing a basis for understanding mercury concentrations in beluga. ... We concluded that marine-based diatoms constitute a major component of the copepod zooplankton diet within the Beaufort Sea Shelf and that river-borne nutrients may also enter the food web, not only through appendicularian tunicates ... but also through copepod feeding. ... (Au)

I, H, J, D, G, F
Animal distribution; Animal food; Animal growth; Animal migration; Animal mortality; Animal reproduction; Animal respiration; Animal waste products; Appendicularia; Arctic cod; Bacteria; Beluga whales; Bioaccumulation; Biological productivity; Biological sampling; Biomagnification; Biomass; Carbon; Copepoda; Diatoms; Fats; Fatty acids; Fish spawning; Fishes; Food chain; Invertebrate eggs; Isotopes; Marine ecology; Mercury; Nitrogen; Phytoplankton; Pollution; Predation; River discharges; Sea ice; Seasonal variations; Sonar; Trophic levels; Zooplankton

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.


CASES2004, Leg 4 (0401) CCGS Amundsen cruise report 7 January to 18 February   /   Deming, J. [Editor]
Québec, Québec : Université Laval, 2004.
[6] p. ; 28 cm.
Cover title.
Indexed a PDF file from the Web.
Reference as an endnote.
ASTIS record 74424.
Languages: English
Web: http://www.cases.quebec-ocean.ulaval.ca/CASES0304_leg4_cruise_report(partial).pdf

This report describes the scientific studies carried out in Leg 4 of the CCGS Amundsen cruise, which included: 1. Report of the activities of the Rosette operator; 2. Ice-atmosphere Interactions and Biological Linkages; 2.1 Surface meteorology / exhanges & Satellite validation; Micrometoerology and Surface Exchanges of Energy, Momentum and CO2; Surface Fluxes; Radiation Exchange and Surface Budget; Heat Exchange; Carbon Flux; Sea Ice and Upper Ocean pCO2 Concentration and Gradients; 6. Carbon Chemistry Report. (ASTIS)

D, G, E, J, L, F
Amundsen (Ship); Biological sampling; Blowing snow; Canadian Arctic Shelf Exchange Study; Carbon cycling; Carbon dioxide; Chemical oceanography; Chemical properties; Heat transmission; Ice cover; Instruments; Measurement; Meteorology; Ocean-atmosphere interaction; Oceanography; Oxygen-18; Radiation budgets; River discharges; Salinity; Sea ice; Sea water; Snow; Solar radiation; Temperature; Temporal variations; Tides; Topography; Water vapour

G0815
Franklin Bay, N.W.T.


CASES2004, Leg 5 (0402) CCGS Amundsen cruise report 18 February to 31 March   /   Deming, J. [Editor]
Québec, Québec : Université Laval, 2004.
[67] p. : ill. ; 28 cm.
Cover title.
Indexed a PDF file from the Web.
ASTIS record 74425.
Languages: English
Web: http://www.cases.quebec-ocean.ulaval.ca/CASES0304_leg5_cruise_report(long).pdf

This report describes the scientific studies undertaken during Leg 5 of the CCGS Amundsen cruise. The scientific observations included: 1. Report on the activities of the rosette operator; 2. Ice-atmosphere Interactions and Biological Linkages; 2.1 Under-ice sediment traps and Ice algae; 2.2 Surface meteorology / exchanges & Satellite validation; 3. Light, Nutrients, Primary and Export Production in ice-free waters; 3.1 Phytoplankton in the water column, nutrients; 3.2 Polish CASES team report; 4. Microbial Communities and Heterotrophy; 4.1 Microbial Ecology; 4.2 Reports from Deming team; 4.3 Cruise report of Japanese CASES (Microzooplankton group); 5. Pelagic Food Web: Structure, Function and Contaminants; 5.1 Contaminants; 5.2 Food web structure; 5.3 Laval University Zooplankton Team cruise report; 6. Water Column Carbon Geochemistry. (ASTIS)

D, G, E, B, H, I, J, L, F
Algae; Amundsen (Ship); Animal food; Arctic cod; Bacteria; Beluga whales; Benthos; Biological sampling; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chemical oceanography; Climate change; Copepoda; Cores; Electrical properties; Equipment and supplies; Fishes; Food chain; Geochemistry; Ice cover; Instruments; Light; Lipids; Marine ecology; Marine mammals; Measurement; Meteorology; Microbial ecology; Microorganisms; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Oceanography; Oxygen-18; Physical properties; Phytoplankton; Plankton; Polar bears; Pollution; Primary production (Biology); Remote sensing; River discharges; Safety; Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Snow; Suspended solids; Temporal variations; Video tapes; Viruses; Water masses; Zooplankton

G07, G0815
Canadian Beaufort Sea; Franklin Bay, N.W.T.; Horton River, N.W.T.; Mackenzie Estuary, N.W.T./Yukon


Life in ice formations at very cold temperatures   /   Deming, J.W.
In: Physiology and biochemistry of extremophiles / Edited by C. Gerday and N. Glansdorff. - Washington, D.C. : American Society for Microbiology Press, 2007, ch. 10, p. 133-135, ill.
References.
ASTIS record 74110.
Languages: English
Libraries: ACU

... The most vibrant and extensive of within-ice microbial ecosystems are those that develop in seasonal ice formed from seawater. ... Why does sea ice favor such vibrant ecosystems, while other forms of ice (e.g., glacial ice) are more often characterized as preserving environments? Fundamentally, the more generously an ice matrix is permeated, even flushed, by the liquid phase, the greater the opportunity for diffusional and transport processes that favor nutrient delivery and exchange and thus biological production. For a given ice volume and temperature, sea ice contains a greater fraction of interior liquid than freshwater ice .... At relatively warm ice temperatures (above -5°C), the ice is well channelized ... and flushed by underlying seawater .... Even at very cold temperatures, the principal freeze-depressing impurities in seawater - its salts - ensure the presence of liquid inclusions or brine-filled pores within the sea-ice matrix. These briny pores have recently been shown to remain interconnected on a scale relevant to microbes, even during the coldest months of winter when sea-ice temperatures can drop to -20°C ... and below, potentially approaching the seawater eutectic of -55°C where the atmosphere is sufficiently cold and the ice free of insulating snow. ... A comparative analysis of some of these ice types - specifically glacial ice over Greenland and Antarctica, and the "permanently" frozen soils or permafrost of the high Arctic during winter - can enlighten information emerging from microbial studies of winter sea ice and its liquid phase. For this chapter, I focus on ice temperatures of -10°C and below, referring to them as "very cold," and on organisms (and their viruses) from the domains of Bacteria and Archaea, referring to them generically as "microbes" or "bacteria." ... (Au)

H, I, J, G, F, C
Active layer; Algae; Archaea; Bacteria; Cold adaptation; Cold physiology; Enzymes; Genetics; Glacial transport; Glaciers; Interstitial water; Isotopes; Melting; Metabolism; Microbial ecology; Microorganisms; Nitrogen; Nitrogen cycling; Oxygen; Permafrost; Salinity; Sea ice; Sea ice ecology; Sea water; Soil microorganisms; Soil temperature; Temperature; Viruses

G02, G15, G0812
Antarctic regions; Arctic regions; Arctic waters; Barrow waters, Alaska; Franklin Bay, N.W.T.; Greenland


Constraints on the origin of sedimentary organic carbon in the Beaufort Sea from coupled molecular 13C and 14C measurements   /   Drenzek, N.J.   Montluçon, D.B.   Yunker, M.B.   Macdonald, R.W.   Eglinton, T.I.
(Marine chemistry, v.103, no. 1-2, Jan. 2007, p. 146-162, ill., maps)
References.
ASTIS record 63264.
Languages: English
Web: doi:10.1016/j.marchem.2006.06.017
Libraries: ACU

The type and flux of organic carbon (OC) delivered from the continents to the sea can both influence, and be influenced by, climate change on regional and global scales. In order to develop a more complete view of OC delivery in the climatically sensitive Arctic region, we measured the stable carbon and radiocarbon isotopic signatures of individual lipid biomarkers and products of kerogen pyrolysis from the surficial sediments of several sites on the Mackenzie Shelf and adjacent slope of the Beaufort Sea. Even carbon numbered fatty acids exhibit a trend of increasing 14C age with increasing chain length, from modern values for the nC14-nC18 homologues to several thousand years old for those nC24. Such depleted 14C values for longer-chain fatty acids likely reflect supply of vascular plant OC that has been pre-aged on the continents for several millennia prior to delivery to the Beaufort Sea. Their corresponding delta13C values support a C3 land plant source. The molecular distributions and 14C and 13C signatures of solvent-extractable alkanes point to at least two sources: higher plant leaf waxes and a 14C-'dead' component likely derived from erosion of organic-rich sedimentary rocks exposed within the Mackenzie River drainage basin. The delta 13C and Delta 14C values of n-hydrocarbon pyrolysis products from the corresponding demineralized sediments also suggest a mixed supply of ancient kerogen and pre-aged vascular plant-derived precursors to the Beaufort Sea. On a bulk level, the trend in sedimentary OC contents, C/N ratios, and delta 13C values point to an overall decrease in the terrigenous input (mainly from the Mackenzie River) with increasing distance offshore, whereas bulk Delta 14C measurements exhibit no trend suggesting a somewhat constant pre-aged component. A coupled molecular isotopic mass balance approach based on the lipid delta 13C and Delta 14C signatures is used to construct a budget of terrestrial, marine, and petrogenic OC burial on the shelf. Results indicate that roughly 40-50% of the carbon currently being buried in the Beaufort Sea is derived from the weathering of ancient sedimentary rock. The balance is composed of marine and terrestrial input, supporting the qualitative description of OC sources given by the bulk and molecular patterns above. This suggests that mass balances utilizing the delta 13C and Delta 14C signatures of biomarkers as endmembers can be used to semi-quantitatively deconvolve multiple sources of organic carbon in marine sediments. (Au)

B, F, D, H, E, J, C
Bathymetry; Biomass; Bottom sediments; Carbon; Carbon cycling; Chromatography; Climate change; Continental shelves; Environmental impacts; Erosion; Fatty acids; Geochemistry; Hydrocarbons; Isotopes; Lipids; Mass balance; Mathematical models; Measurement; Ocean floors; Plants (Biology); Primary production (Biology); Radiocarbon dating; Rivers; Sediment transport; Sedimentary rocks; Shale; Soils; Suspended solids; Watersheds; Weathering; Wetlands

G07, G0812, G03
Arctic Ocean; Canadian Beaufort Sea; Mackenzie River, N.W.T.


Modelling subsurface chlorophyll maxima in the Amundsen Gulf   /   Dumont, D.   Martin, J.   Tremblay, J.-E.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 208
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67145.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

A nitrogen-based ecosystem model coupled to a water column turbulence model (Global Ocean Turbulence Model) is used to simulate the structure and evolution of the pelagic phytoplankton bloom in the Amundsen Gulf. The formation of subsurface chlorophyll maxima (SCM) is studied with respect to different scenarios of photoacclimatation and settling velocity. Other parameters influencing the phytoplankton growth are taken from values relevant to the region or other arctic ecosystems. Simulation results are compared with fluorescence and nutrient data collected from 2003 (CASES) to 2008 (ArcticNet, CFL) which reveal a strong correlation between the depth of SCM and the nitracline. Photoinhibited algae sinking at a constant velocity (~0.4 m/day) reproduce the main characteristics of the spring bloom in the Amundsen Gulf. The settling velocity determines if the bloom manifests as a SCM while photoinhibition controls the productivity when the maximum nitrate intake parameter and the initial conditions are unchanged. For particular sinking rates, photoinhibited algae grow much faster than photosaturated ones, demonstrating the strong coupling that exists between physical and physiological parameters and the complexity of this rather simple biological model. The ecosystem model includes a microbial loop and a parameterisation of the higher trophic levels that triggers a phytoplankton production based on regenerated nitrogen (ammonium). The turbulence model uses a wide variety of well-tested turbulence closures, and is designed to be embedded in 3D circulation models. Thus, the model presented here has the potential to further investigate the role of SCM in the carbon and nitrogen cycle at the basin scale. (Au)

H, D, J
Ammonium; Carbon cycling; Chlorophyll; Fluorometry; Light; Marine ecology; Mathematical models; Microorganisms; Nitrogen; Nitrogen cycling; Phytoplankton; Plant growth; Plant nutrition; Plant physiology; Primary production (Biology); Sedimentation; Suspended solids; Velocity

G0815
Amundsen Gulf, N.W.T.


Investigations of newly formed sea ice in the Cape Bathurst polynya : 1. Structural, physical, and optical properties   /   Ehn, J.K.   Hwang, B.J.   Galley, R.   Barber, D.G.
(Journal of geophysical research, v.112, no. 5, C05002, May 2007, 15 p., ill., maps)
References.
ASTIS record 62070.
Languages: English
Web: doi:10.1029/2006JC003702
Libraries: ACU

The physical, structural, and optical properties of newly formed ice types were studied in the Cape Bathurst polynya (71°N, 127°W) during fall freezeup in October to early November 2003. Variable meteorological conditions with occasional snowfall resulted in the formation of numerous ice types and surface conditions. Ice samples were collected from horizontally homogeneous surfaces representative of the area. Crystallographic analysis on 33 ice cores revealed highly variable growth conditions and formation mechanisms in the area. The mean fraction of granular ice was 33%, while intermediate granular-columnar and columnar ice contributed 37% and 30%, respectively. Salinity profiles in the ice were C-shaped and as the ice grew thicker, bulk salinities decreased according to 4.582 + 13.358/h(i) (cm). These conditions resulted in brine volumes ranging from 4% to 46%. Bare ice surfaces commonly formed a high salinity brine skim layer due to brine expulsion. Salinities up to 40‰ were observed in this layer. Under suitable conditions frost flowers formed on the ice, and their presence was related to characteristic ice microstructure with crystals that appeared disc-like in shape. Fine-grained snow-ice was formed when snow merged with surface brine to create a complex hypersaline surface at the snow/ice interface. The spectral reflectance for the thin ice types was most strongly related to surface conditions. The presence of frost flowers significantly increased the reflectance independent of snow precipitation. Any increase in ice thickness was found to have little effect on the reflectance once a 20-30 mm thick snow layer was present. (Au)

G, E, D, A
Atmospheric pressure; Atmospheric temperature; Classification; Cores; Crystals; Density; Electromagnetic radiation; Formation; Frazil ice; Gases in ice; Grease ice; Growth; Ice floes; Identification; Logistics; Measurement; Ocean temperature; Optical properties; Pancake ice; Physical properties; Polynyas; Salinity; Sea ice; Size; Snow; Spatial distribution; Spectroscopy; Surface properties; Temperature; Temporal variations; Thickness; Velocity; Winds

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Bio-optical and structural properties inferred from irradiance measurements within the bottommost layers in an Arctic landfast sea ice cover   /   Ehn, J.K.   Mundy, C.J.   Barber, D.G.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C3, C03S03, Mar. 2008, 12 p., ill., maps)
References.
ASTIS record 64588.
Languages: English
Web: doi:10.1029/2007JC004194
Libraries: ACU

Irradiance spectra were measured at vertical increments within the bottommost layers of landfast sea ice with the aid of divers in Franklin Bay, Canada, in an effort to obtain input parameters for bio-optical modeling of sea ice. The study took place between 22 April and 9 May 2004 during the overwintering stage of CASES (Canadian Arctic Shelf Exchange Study). The ice was about 1.8 m thick with a snow cover of variable thickness (~0.04 to 0.4 m). Ice surface temperatures increased from about -12° to -6.4°C during the sampling period, while ice temperatures within the bottommost portion under study ranged from -3.0° to -1.2°C. Ice algae were visible within the bottommost centimeters of the sea ice. This algae layer had a marked effect on the spectral distribution of transmitted irradiance beneath the ice. Particulate absorption spectra, ap(lambda), measured from melted ice samples showed evidence of chloroplastic pigment degradation and could not fully explain the shape of the in situ diffuse attenuation coefficient, Kd(lambda), for the algal layer. Interior ice layers, however, did show absorption curves similar to ap(lambda) from samples, suggesting the presence of degraded algal pigments within these layers. The discrete ordinates radiative transfer (DISORT) code was iterated in an inverse approach to estimate ap(lambda) and the scattering coefficient, b(tot), from the irradiance profiles. For the bottom 0.1 m of the sea ice, b(tot) was around 400/m, while at the 0.1- to 0.2-m layer from the ice bottom it decreased to 165/m. Using ap(lambda) combined with wavelength independent b(tot) as inputs to DISORT seem to adequately explain the radiative transfer near the bottom of first-year sea ice provided that adjustments were made to the brine volume fraction. (Au)

G, H
Algae; Chlorophyll; Cores; Crystals; Density; Fast ice; Fluorometry; Formation; Gases in ice; Growth; Instruments; Light; Mathematical models; Measurement; Optical properties; Physical properties; Salinity; Sea ice; Snow; Snow cover; Spectroscopy; Suspended solids; Thickness

G0815
Franklin Bay, N.W.T.


Solar radiation interactions with seasonal sea ice   /   Ehn, J.K.   Barber, D. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2008.
xii, 225, p. : ill, maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR41262)
ISBN 978-0-494-41262-6
References.
Thesis (Ph.D.) - University of Manitoba, Winnipeg, Man., 2008.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74967.
Languages: English
Libraries: OONL

Presently, the Arctic Ocean is undergoing an escalating reduction in sea ice and a transition towards a seasonal sea ice environment. This warrants detailed investigations into improving our understanding of the seasonal evolution of sea ice and snow covers, and their representation in climate models. The interaction of solar radiation with sea ice is an important process influencing the energy balance and biological activity in polar seas, and consequently plays a key role in the earth's climate system. This thesis focuses on characterization of the optical properties - and the underlying physical properties that determine them - of seasonal sea ice during the fall freeze-up and the spring melt periods. Both periods display high spatial heterogeneity and rapid temporal changes in sea ice properties, and are therefore poorly understood. Field data were collected in Amundsen Gulf/Franklin Bay (FB), southern-eastern Beaufort Sea, in Oct.-Nov. 2003 and Apr. 2004 and in Button Bay (BB), western Hudson Bay, in Mar.-May 2005 to address (1) the temporal and spatial evolution of surface albedo and transmittance, (2) how radiative transfer in sea ice is controlled by its physical nature, and (3) the characteristics of the bottom ice algae community and its effect on the optical properties. The fall study showed the importance of surface features such as dry or slushy bare ice, frost flowers and snow cover in determining the surface albedo. Ice thickness was also important, however, mostly because surface features were associated with thickness. For example, nilas (<10 cm thick) was typically not covered by a snow layer as snow grains were dissolved or merged with the salty and warm brine skim layer on the surface, while surface conditions on thicker ice types were cold and dry enough to support a snow cover. In general, the surface albedo increased exponentially with an ice thickness increase, however, variability within ice thickness types were very large. It is apparent that a more complete treatment of brine movement towards the surface ice of the ice cover and the formation of surface features - such as frost flowers or slush layers - is required to understand the albedo of newly formed sea ice. The sea ice had reached its maximum thickness by late April in both FB and BB (~1.8 m vs. 1.5-1.7 m). However, surface conditions differed notably as surface melting had not been initiated in FB, while melting had progressed to an advanced stage in BB, illustrating the difference in climate between the two regions (Arctic vs. sub-Arctic). The shortwave partitioning between the atmosphere, sea ice and the ocean - as well as within the sea ice - was strongly affected by diurnal freeze-thaw processes and synoptic weather events that controlled the optical characteristics of the surface. In spring, in situ measurements with a high vertical resolution were conducted within the bottom sea ice layers. The optical properties were strongly affected by ice algae present in the bottom few centimeters. Particulate absorption decreased quickly within the ice above the living algae layer, and showed characteristics of detrital matter. The optical properties for the bottom layers of the sea ice were found to significantly differ from interior ice. This is expected as the bottom ice is very porous and has a lamellar platelet structure, in addition to containing high concentrations of biological matter. These findings emphasize the importance of processes occurring near the surface and bottom boundaries in determining radiative transfer in sea ice covers. Ultimately, a focus on linking numerous aspects of sea ice physics and biology is required in order to predict the seasonal evolution of the sea ice cover in a changing climate. (Au)

G, F, E, D, H
Albedo; Algae; Atmospheric circulation; Atmospheric humidity; Atmospheric pressure; Atmospheric temperature; Boreholes; Boundary layers; Carbon dioxide; Chlorophyll; Classification; Clouds; Cores ; Crystals; Density; Diurnal variations; Electrical properties; Energy budgets; Fast ice; Fluorometry; Formation; Frazil ice; Gases in ice; Ice fog; Mathematical models; Melting; Ocean temperature; Optical properties; Pancake ice; Physical properties; Polynyas; Salinity; Sea ice; Seasonal variations; Slush; Snow; Snow cover; Snow metamorphism; Snowmelt; Solar radiation; Spatial distribution; Surface properties; Surface temperature; Suspended solids; Temporal variations; Theses; Thickness; Velocity; Water vapour; Winds

G0814, G07, G0815
Amundsen Gulf, N.W.T.; Button Bay, Nunavut; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Hudson Bay


Downstream nutrient changes through the Mackenzie River delta and estuary, western Canadian Arctic   /   Emmerton, C.A.   Lesack, L. [Supervisor]   Vincent, W.F. [Supervisor]   Quinton, W. [Supervisor]
Burnaby, B.C. : Simon Fraser University, 2006.
xv, 181 p. : ill., maps ; 28 cm..
(ProQuest Dissertations & Theses publication, no. MR24032)
ISBN 978-0-494-24032-8
Thesis (M.Sc.) - Simon Fraser University, Burnaby, B.C., 2006.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
Appendices.
References.
ASTIS record 74971.
Languages: English
Libraries: OONL

The effect of the large lake-rich delta and freshwater-saltwater transition zone (FSTZ) on nutrients from the Mackenzie River was investigated during open water of 2003-2004. Water volume storage in the Mackenzie Delta at peak levels was estimated by quantitatively partitioning the landscape (via GIS analysis) into discrete floodplain lake, wetland and channel environments. A river and lake mixing model and biogeochemical sampling of upstream and downstream delta channels were used to estimate average nutrient composition of water outflow from the delta. Results showed that the delta was a sink for particulates and dissolved inorganic nutrients while dissolved organic matter was enhanced. The composition of river water across the FSTZ was investigated during a mid summer cruise in 2004. Results showed particulate, dissolved inorganic nutrient and dissolved organic carbon patterns typical of most estuaries while dissolved organic nitrogen and phosphorus increased across the FSTZ, atypical of most estuaries. (Au)

F, E, J, G, D
Biological productivity; Carbon; Chemical oceanography; Chemical properties; Chlorophyll; Climate change; Dissolved organic carbon; Estuarine ecology; Floods; Fresh-water ecology; Hydrology; Ice cover; Lakes; Nitrogen; Particulate organic matter; Phosphorus; River deltas; River discharges; Runoff; Seasonal variations; Sediment transport; Sedimentation; Suspended solids; Theses; Water masses

G0812, G07, G03
Arctic Ocean; Beluga Bay, N.W.T.; Kugmallit Bay, N.W.T.; Mackenzie Delta, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River region, N.W.T.; Mackenzie River, N.W.T.; Shallow Bay, N.W.T.


Lake abundance, potential water storage, and habitat distribution in the Mackenzie River Delta, western Canadian Arctic   /   Emmerton, C.A.   Lesack, L.F.W.   Marsh, P.
(Water resources research, v. 43, W05419, 2007, 14 p., ill., maps)
References.
Also available on the Web.
ASTIS record 64869.
Languages: English
Web: http://www.agu.org/pubs/crossref/2007/2006WR005139.shtml
Web: doi:10.1029/2006WR005139
Libraries: ACU

The complete landscape surface of the active Mackenzie River Delta (13,135 km²) was manually partitioned into discrete lakes (3331 km²), channels (1744 km²), wetlands (1614 km²), and dry floodplain area (6446 km²) via GIS analysis of digital topographic maps recently available for the system. The census total of lakes (49,046) is almost twice as large as prior estimates. Using this new information, total lake volume in the delta during the post river flooding period is estimated as 5.4 km³. Total floodwater storage in the delta lakes and floodplain at peak water levels is estimated at 25.8 km³ and thus is equivalent to about 47% of Mackenzie River flow (55.4 km³/yr) during the high-discharge period of delta breakup. During this period the stored river water can be envisioned in the form of a thin layer of water (2.3 m thick on average) spread out over 11,200 km² of lakes and flooded vegetation and exposed to 24 h/d solar irradiance. Consequently, this temporarily stored water has significant potential to affect the composition of river water flowing to the Beaufort Shelf as it recedes to the river channels after the flood peak. (Au)

F, D, A, E, J
Bathymetry; Biological productivity; Breakup; Chemical oceanography; Chemical properties; Climate change; Environmental impacts; Floods; Fresh-water ecology; Geographic information systems; Hydrology; Lakes; Land classification; Mathematical models; Ocean currents; Oceanography; Primary production (Biology); River deltas; River discharges; River ice; Rivers; Runoff; Salinity; SAR; Sediment transport; Stream flow; Water level; Watershed management; Watersheds; Wetlands; Wildlife habitat

G0812, G07, G03
Arctic Ocean; Canadian Beaufort Sea; Mackenzie Delta, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River region, N.W.T.


Mackenzie River nutrient delivery to the Arctic Ocean and effects of the Mackenzie Delta during open water conditions   /   Emmerton, C.A.   Lesack, L.F.W.   Vincent, W.F.
(Global biogeochemical cycles, v. 22, no. 1, GB1024, Mar. 2008, 15 p., ill., maps)
References.
Auxiliary data available on-line.
ASTIS record 64880.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/221.pdf
Web: doi:10.1029/2006GB002856
Libraries: ACU

Large rivers have a strong influence on the Arctic Ocean, but little attention has been given to the biogeochemical effect that lake-rich delta floodplains may have on river waters prior to marine discharge. We assessed the effect of the Mackenzie Delta on riverine fluxes of nutrients and organic matter to the Arctic Ocean during the open water period of 2004. Using a new estimate of peak off-channel water storage in the delta floodplain, a two-source mixing model was developed (channel water plus recovery of off-channel water) to estimate the volume-weighted nutrient composition of river water after the off-channel water was recovered from the delta during the hydrograph recession period. Results with the delta effect included (i.e., with recovery of off-channel water) relative to results with the effect omitted (i.e., analogous to historical monitoring upstream of the delta) show particulate levels were 10-18% lower, but enriched in organic content (POC:TSS, PN:TSS, PP:TSS) by 75-280%; dissolved inorganic nutrients were lower (NO3- 14%; SRP 14%; SRSi 5%) except for ammonium (10%); and dissolved organic matter was higher (DOC 15%; DON 62%; DOP 239%). The resulting nutrient quality (C:N:P stoichiometry) was more enriched in carbon (TOC:TP) by 79% and in nitrogen (TN:TP) by 77% relative to phosphorus. Model results were compared against nutrient measurements throughout the delta channel network taken three times over this same period, and differences from upstream to downstream matched reasonably well to the model, though they also suggested the delta effect may be more complex than represented by the model. Our results generally indicate the Mackenzie Delta has an important effect on the magnitude and quality of riverine particulates and nutrients prior to entering the sea. Such an effect has not been quantified in prior work and is likely to be important in other arctic rivers with lake-rich deltas. Our enhanced sampling of the high-discharge period during early hydrograph recession has also better captured the detailed composition of C, N, and P constituents in the river water, ultimately leading to improved estimates of nutrient levels and overall nutrient quality for the open water period that differ appreciably from prior observations on the Mackenzie River. (Au)

F, A, G, B
Ammonium; Breakup; Carbon; Dissolved organic carbon; Floods; Hydrography; Lakes; Mathematical models; Nitrogen; Nitrogen oxides; Particulate organic matter; Phosphorus; River deltas; River discharges; River ice; Rivers; Runoff; Seasonal variations; Sediment transport; Sedimentation; Silica; Snowmelt; Spatial distribution; Suspended solids; Water level

G0812
Arctic Red River, N.W.T.; Mackenzie Delta, N.W.T.; Mackenzie River, N.W.T.; Peel River, N.W.T./Yukon


Nutrient and organic matter patterns across the Mackenzie River, estuary and shelf during the seasonal recession of sea-ice   /   Emmerton, C.A.   Lesack, L.F.W.   Vincent, W.F.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 741-755, ill., maps)
Appendix A is supplementary data that is available online.
References.
ASTIS record 65242.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/227.pdf
Web: doi:10.1016/j.jmarsys.2007.10.001
Libraries: ACU

Suspended material, nutrients and organic matter in Mackenzie River water were tracked along a 300 km transect from Inuvik (Northwest Territories, Canada), across the estuarine salinity gradient in Kugmallit Bay, to offshore marine stations on the adjacent Mackenzie Shelf. All particulates measured (SPM, POC, PN, PP) declined by 87-95% across the salinity gradient and levels were generally below conservative mixing. Organic carbon content of suspended material decreased from 3.1% in the river to 1.7% in shelf surface waters while particulate C:N concurrently decreased from 17.1 to 8.6. Nitrate and silicate concentrations declined by more than 90% across the salinity gradient, with nitrate concentrations often below the conservative mixing line. Phosphate concentrations increased from 0.03 µmol/L in the river to 0.27 µmol/L over shelf waters, thereby changing the inorganic nutrient regime downstream from P to N limitation. Dissolved organic carbon decreased conservatively offshore while dissolved organic N and P persisted at high levels in the Mackenzie plume relative to river water, increasing 2.7 and 25.3 times respectively. A deep chlorophyll-a maximum was observed at two offshore stations and showed increases in most nutrients, particulates and organic matter relative to the rest of the water column. During river passage through the Mackenzie estuary, particulate matter, dissolved organic carbon and inorganic nutrients showed sedimentation, dilution and biological uptake patterns common to other arctic and non-arctic estuaries. Alternatively, inorganic content of particles increased offshore and dissolved organic N and P increased substantially over the shelf, reaching concentrations among the highest reported for the Arctic Ocean. These observations are consistent with the presence of a remnant ice-constrained ('stamukhi') lake from the freshet period and a slow flushing river plume constrained by sea-ice in close proximity to shore. Nutrient limitation in surface shelf waters during the ARDEX cruise contributed to the striking deep chlorophyll-a maximum at 21 m where phytoplankton communities congregated at the margin of nutrient-rich deep ocean waters. (Au)

F, D, G, B, H, A
Carbon; Chlorophyll; Chromatography; Continental shelves; Dissolved organic carbon; Estuaries; Fast ice; Hydrology; Melting; Nitrogen; Ocean temperature; Pack ice; Particulate organic matter; Phosphorus; Phytoplankton; Plant nutrition; River discharges; Rivers; Salinity; Sea ice; Sea water; Seasonal variations; Sedimentation; Silicates; Spatial distribution; Spectroscopy; Stamukhi; Suspended solids; Temperature; Water masses

G07, G0812
Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Kugmallit Bay, N.W.T.; Middle Channel (Mackenzie River), N.W.T.


Meteorological characteristics of the Canadian Arctic Shelf Exchange Study   /   Fisico, T.D.   Hanesiak, J. [Supervisor]
Winnipeg, Man. : University of Manitoba, c2008.
xiii, 114 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR41404)
ISBN 978-0-494-41404-0
References.
Thesis (M.Sc.) - University of Manitoba, Winnipeg, Man., 2008.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74810.
Languages: English
Libraries: MWU OONL

The CASES meteorological program began October 22, 2003 and continued until June 20, 2004 (day 295 to day 172, herein "observational period " or "study period"). The program consisted of manual meteorological surface observations taken on the hour, atmospheric profiling of temperature, moisture and low-boundary layer winds, continuous cloud base height, integrated column water vapor and cloud liquid water measurements, as well as automated visibility observations. Few continuous meteorological data sets have been made during the fall-winter-spring period in the Southern Beaufort Sea sea-ice environment. Presented here is an overview of the hemispheric, synoptic and local scale meteorology observed from the CCGS Amundsen during the observational period. First, NCEP I reanalysis data were used to examine how the CASES year compared to the 1971-2000 30-year "normal". Second, surface 3-hourly isobaric analysis were used to track low-pressure disturbances (LPDs) affecting the CASES region during the observational period to reveal their location of origin and evolution. Third, a monthly (and overall) climatology of several meteorological variables (e.g. cloud type/amount/ceiling, adverse weather, wind, temperature) was produced. Finally, a comparison of data collected from the ship with surrounding Meteorological Service of Canada station data and an investigation into the accuracy of daily averages from NCEP I and NCEP II reanalysis data, North American Regional Reanalysis (NARR) and GEM-Regional analysis data is presented. The investigations reveal the weaknesses and strengths of popular and widely used model data with respect to actual station data with the intentions of improving atmospheric modeling in arctic regions. (Au)

E, F, G
Atmospheric humidity; Atmospheric pressure; Atmospheric temperature; Blowing snow; Boundary layers; Clouds; Density; Diurnal variations; Heat transmission; Mathematical models; Measurement; Meteorological instruments; Meteorology; Precipitation (Meteorology); Sea ice; Seasonal variations; Snow; Storms; Synoptic climatology; Temporal variations; Thermal properties; Theses; Velocity; Water vapour; Weather stations; Winds

G0815, G0812, G02, G081, G061
Alaska, Gulf of; Arctic waters; Canadian Arctic waters; Franklin Bay, N.W.T.; Parry, Cape, N.W.T.; Paulatuk, N.W.T.


Particulate organic carbon fluxes on the slope of the Mackenzie shelf (Beaufort Sea) : physical and biological forcing of shelf-basin exchanges   /   Forest, A.   Sampei, M.   Hattori, H.   Makabe, R.   Sasaki, H.   Fukuchi, M.   Wassmann, P.   Fortier, L.
(Journal of marine systems, v. 68, no. 1-2, Nov. 2007, p. 39-54, ill., maps)
References.
ASTIS record 63260.
Languages: English
Web: doi:10.1016/j.jmarsys.2006.10.008
Libraries: ACU

To investigate the mechanisms underlying the transport of particles from the shelf to the deep basin, sediment traps and oceanographic sensors were moored from October 2003 to August 2004 over the 300- and 500-m isobaths on the slope of the Mackenzie Shelf (Beaufort Sea, Arctic Ocean). Seasonal variations in the magnitude and nature of the vertical particulate organic carbon (POC) fluxes were related to sea-ice thermodynamics on the shelf and local circulation. From October to April, distinct increases in the POC flux coincided with the resuspension and advection of shelf bottom particles by thermohaline convection, windstorms, and/or current surges and inversions. Once resuspended and incorporated into the Benthic Nepheloid Layer (BNL), particles of shelf origin were transported over the slope by the isopycnal intrusion of the BNL into the Polar-Mixed Layer off-shelf. Offshore transport of the resuspended particles allowed them to settle over the slope. The resulting vertical POC flux at the shelf-basin boundary amounted to 1.0 g C / m²/y or 58% of the annual POC flux over the 300-m isobath. Consistent with the resuspension of shelf sediments, POC fluxes in fall/winter were characterized by a high terrigenous fraction (25-60%), the dominance of small flagellate cells, and increasingly degraded fecal pellets with time. In late May-early June, a short-duration POC flux maximum characterized by high POC:PON ratio and more positive delta 13C resulted from the direct sinking of ice algae and transparent exopolymeric matter flushed from melting sea-ice. In July, a last sedimentation event coincided with the retreat of the sea-ice cover, phytoplankton production from a subsurface bloom, and the sinking of the intact fecal pellets of large herbivorous copepods and appendicularians. Our results confirm the importance of sea-ice thermodynamics and BNL resuspension in promoting the transfer of POC from the shelf to the deep basin in fall/winter. The actual contribution of the summer biological production to the shelf-basin flux of POC remains uncertain. (Au)

D, J, I, H, E, G
Algae; Animal behaviour; Animal food; Animal waste products; Appendicularia; Bathymetry; Benthos; Biological productivity; Bottom sediments; Carbohydrates; Carbon; Carbon cycling; Carbon dioxide; Chemical oceanography; Climate change; Climatology; Continental shelves; Copepoda; Mass balance; Measurement; Melting; Microorganisms; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Oceanographic instruments; Oceanography; Phytoplankton; Salinity; Sea ice; Sea water; Seasonal variations; Sediment transport; Sedimentation; Stamukhi; Sugars; Suspended solids; Thermodynamics; Trophic levels; Water masses; Winds; Zooplankton

G07, G03
Canada Basin, Arctic Ocean; Canadian Beaufort Sea


The annual cycle of particulate organic carbon export in Franklin Bay (Canadian Arctic) : environmental control and food web implications   /   Forest, A.   Sampei, M.   Makabe, R.   Sasaki, H.   Barber, D.G.   Gratton, Y.   Wassmann, P.   Fortier, L.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C3, C03S05, Mar. 2008, 14 p., ill., maps)
References.
A correction to this paper is published in: Journal of geophysical research, v.113, no. C3, C03S99 (doi:10.1029/2008JC004782).
ASTIS record 63908.
Languages: English
Web: doi:10.1029/2007JC004262
Libraries: ACU

As part of the Canadian Arctic Shelf Exchange Study (CASES), we assessed the importance of new production and resuspension in determining the nature and magnitude of the deep (210 m) particulate organic carbon (POC) flux from October 2003 to September 2004 in central Franklin Bay. In spring and summer, phytoplankton production was nutrient-limited in the stratified surface layer and the initial spring bloom evolved into a subsurface chlorophyll maximum (SCM) at the nutricline. Large herbivorous calanoid copepods intercepted little of the initial bloom but grazed intensely on the SCM. The phytoplankton and fecal pellet fluxes culminated simultaneously in July-August (24 and 23 mg C/m²/d, respectively). The detrital POC flux peaked in September (52 mg C/m²/d), coincident with wind-induced resuspension of recently settled POC. In the fall, detrital POC fluxes increased again to 22 mg C/m²/d, following the off-shelf transport of terrigenous POC carried by the Mackenzie River plume and POC resuspended by wind on the shelf. In winter, the relatively weak POC fluxes (2-7 mg C/m²/d, detrital at 90%) resulted from the settling down of resuspended sediments. We propose a conceptual model in which the ecosystem of Franklin Bay shifts from an algal to a detrital mode according to seasonal changes in the relative importance of fresh and old POC supplies. On the basis of this model, the ecosystem of southeastern Beaufort Sea could evolve toward a less productive equilibrium dominated by sediment resuspension in response to the ongoing reduction of the ice cover. (Au)

H, I, J, D, F, E, G
Algae; Animal food; Animal population; Animal waste products; Benthos; Biomass; Carbon; Chlorophyll; Copepoda; Diatoms; Fluorometry; Food chain; Formation; Ice cover; Melting; Microorganisms; Ocean currents; Ocean temperature; Phytoplankton; Plant nutrition; Primary production (Biology); River discharges; Salinity; Sea ice; Seasonal variations; Sediment transport; Sedimentation; Suspended solids; Velocity; Water masses; Winds; Zooplankton

G0815
Amundsen Gulf, N.W.T.; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon


Temporal variability of the deep particle flux in central Amundsen Gulf (western Canadian Arctic) : evidence for change or continuity?   /   Forest, A.   Sampei, M.   Lalande, C.   Sasaki, H.   Fortier, L.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 214
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67156.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Monitoring the downward flux of particulate matter in Arctic marine environments is of crucial importance to our understanding of climate-related changes in sediment transport and biological production. As part of the ArcticNet Marine Observatory Program, mooring lines equipped with sequential sediment traps have been maintained in Amundsen Gulf (southeastern Beaufort Sea, Inuvialuit) to collect settling particles in situ. In particular, the large particle interceptor trap Technicap(c) PPS 5/2 (24-cups, 1-m² aperture) deployed at ca. 430 m depth over the deepest isobath (~550 m) of Amundsen Gulf allowed us to build a 4-year time series (October 2003 to August 2007) of the deep particle export in the region. Here, we present the mass (dry weight, DW), particulate organic carbon (POC) and particulate nitrogen (PN) downward fluxes obtained at this deep location during the entire mooring deployment. Vertical fluxes of aluminum (Al), silicates (BioSi/LithoSi), carbonates (CaCO3) and stable isotopes (delta 13C/delta 15N) analyzed during the 2003-2004 campaign of the Canadian Arctic Shelf Exchange Study (CASES) are also reported to estimate the amount of terrigenous matter transported to the deep water column. Changing sea ice conditions together with relevant current meter data and CTD profiles recorded in Amundsen Gulf over the study period are presented as well to put the particle flux time series in an environmental context. All these complementary results are discussed in order to document the potential relationships between surface-water regime, lateral mid-water advection, and the deep export of particulate matter (especially organic carbon). (Au)

D, G
Aluminum; Carbon; Carbonates; Isotopes; Nitrogen; Ocean currents; Ocean temperature; Salinity; Sea ice; Sediment transport; Sedimentation; Silicates; Suspended solids; Temporal variations

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Winter pulses of Pacific-origin water and resuspension events along the Canadian Beaufort slope revealed by a bottom-moored observatory   /   Forest, A.   Sampei, M.   Rail, M.-E.   Gratton, Y.   Fortier, L.
In: Oceans '08 MTS/IEEE Quebec : oceans, poles & climate : technological challenges, Sept. 15-18, 2008, Quebec City Convention Centre, Quebec City, Canada. - [Piscataway, N.J.] : IEEE, 2008, [8] p., ill., maps
References.
ASTIS record 74282.
Languages: English
Web: doi:10.1109/OCEANS.2008.5152010
Libraries: ACU

To assess hydrodynamics and particle transport variability at the Arctic shelf-basin boundary, a bottom-moored marine observatory was maintained from October 2003 to October 2006 over the ca. 300 m isobath on the slope of the Canadian Beaufort Sea (western Arctic Ocean). The mooring line was equipped at ~200 m depth with an oceanographic multi-sensors and a sequential sediment trap. Each winter, an abrupt and brief (<8 days) amplification of the subsurface eastward circulation was recorded when sea ice was covering most of the western Arctic Ocean. Compared to a mean background of 9 cm/s, the highest daily velocities recorded during the events reached 67, 94 and 62 cm/s, respectively in 2004, 2005 and 2006. The temperature-salinity signatures of the amplified flows displayed the signal of Pacific-origin shelf waters. The analysis of current components enabled us to propose that we detected the external limit of a submerged eddy formed via baroclinic instability of the shelfbreak current. We suggest that the periodic synchronicity of high atmospheric pressure along with rapid ice formation over the western Arctic Shelf were able to produce such instabilities in the jet. Each winter, the energy carried by the Pacific-origin water pulses was sufficient to erode the upper continental slope, producing marked sediment resuspension. Accordingly, the downward particle flux estimated with the sediment trap reached their annual peak values at the same time as the abrupt current surges were recorded. While the mean daily flux was ~0.1 g/m²/d over the three-year period, the vertical mass flux reached ~0.8 g/m²/d in both January 2004 and February 2006. In January 2005, however, the sediment trap clogged (>10 g/m²/d) as a result of the strong water pulse detected during this month. Our study stresses the importance of maintaining long-term marine observatories along the Arctic shelfbreak to better elucidate the links between the changing atmosphere-sea ice-ocean system and biogeochemical fluxes in the Canadian Beaufort Sea. (Au)

D, B, E, G
Atmospheric pressure; Atmospheric temperature; Bottom sediments; Continental shelves; Formation; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Oceanographic instruments; Oceanography; Salinity; Sea ice; Seasonal variations; Sedimentation; Submarine topography; Suspended solids; Temporal variations; Water masses; Winds

G07
Canadian Beaufort Sea


Influence du climat sur les facteurs physiques et biologiques qui contrôlent le flux vertical de carbone organique particulaire dans le sud-est de la mer de Beaufort (océan Arctique)   /   Forest, A.   Fortier, L. [Supervisor]
Québec, Québec : Université Laval, 2008.
xviii, 180 p. : ill., maps ; 28 cm.
Appendix.
References.
Thesis (Ph.D.) - Université Laval, Québec, Québec, 2008.
Front material, Chapter 1 (Introduction générale), and Chapter 5 (Conclusion générale) in French; Chapters 2, 3, and 4 in English.
Indexed a PDF file available online through Université Laval.
ASTIS record 74972.
Languages: English or French
Web: http://www.theses.ulaval.ca/2008/25884/25884.pdf
Libraries: QQLA

Fluxes of particulate organic carbon (POC) are key determinants of the Earth's climate regulation. The rapid climatic changes which affect the high northern latitudes are likely to abruptly modify the dynamics of POC fluxes in the Arctic Ocean. The implications of such modifications for the arctic marine food web and the global climate are unknown. In order to examine the physical and biological control of vertical POC fluxes in the Arctic Ocean, sequential sediment traps were moored in the area of the Canadian Beaufort Shelf. A first study on the continental slope revealed the partial horizontal functioning of POC fluxes in ice-covered seas, since approximately half of the flux collected at this location was related to the lateral advection of particles by thermohaline convection. In the eventuality of an increase in the quantity of organic material produced in a summer ice-free Arctic Ocean, the sequestration of POC would thus be enhanced because of the formation of a greater volume of seasonal sea ice. The subsequent investigation of the annual cycle of vertical POC export on the Arctic Shelf allowed the development of a conceptual model of this ecosystem which varies according to the relative importance of fresh and old POC supplies. This model suggests that if climate change induces an increase in the terrigenous and detritus inputs on Arctic Shelves, the generation of an ecosystem based on the recycling of POC would be favoured. Finally, the examination of the interannual variability of POC fluxes in margin of the Shelf revealed that the highest vertical POC fluxes were detected in concomitance with a late ice retreat, a strong pulsed bloom and an apparent mismatch with the pelagic consumers. This result supports that an early ice break-up and a longer season of primary production in the Arctic Seas would be more benefit to the trophic transfer of POC than to its vertical export. The general conclusion of the thesis illustrates the complexity of predicting the nature and magnitude of vertical POC fluxes in an Arctic Ocean affected by multiple environmental changes. The long-term maintenance of marine observatories (e.g., mooring lines) is thus essential to a better synthesis of the links that connect climate variability and the organic carbon cycle in high northern latitudes. (Au)

D, J, I, H, E, G, B
Algae; Animal behaviour; Animal food; Animal waste products; Appendicularia; Bathymetry; Benthos; Biological productivity; Biomass; Bottom sediments; Breakup; Carbohydrates; Carbon; Carbon cycling; Carbon dioxide; Chemical oceanography; Chlorophyll; Climate change; Climatology; Continental shelves; Copepoda; Diatoms; Food chain; Formation; Hydrography; Ice cover; Marine ecology; Mass balance; Melting; Microorganisms; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Oceanographic instruments; Oceanography; Phytoplankton; Plant nutrition; Primary production (Biology); Salinity; Sea ice; Sea water; Seasonal variations; Sediment transport; Sedimentation; Suspended solids; Temporal variations; Theses; Trophic levels; Velocity; Water masses; Winds; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon


Three-year assessment of particulate organic carbon fluxes in Amundsen Gulf (Beaufort Sea) : satellite observations and sediment trap measurements   /   Forest, A.   Bélanger, S.   Sampei, M.   Sasaki, H.   Lalande, C.   Fortier, L.
(Deep-sea research. Part I, Oceanographic research papers, v. 57, no. 1, Jan. 2010, p. 125-142, ill., maps)
References.
ASTIS record 71790.
Languages: English
Web: doi:10.1016/j.dsr.2009.10.002
Libraries: ACU

Surface concentrations and vertical fluxes of particulate organic carbon (POC) were assessed in the Amundsen Gulf (southeastern Beaufort Sea, Arctic Ocean) over the years 2004 to 2006 by using ocean color remote-sensing imagery and sequential sediment traps moored over the ca. 400 m isobath. Environmental conditions (sea ice, wind) and oceanographic variables (temperature, salinity, fluorescence and currents) were investigated to explain the variability of POC data. Annual downward POC fluxes in 2004, 2005 and 2006 cumulated, respectively, to 3.3, 4.2 and 6.0 g C/m²/yr at 100 m depth, and to 1.3, 2.2 and 3.3 g C/m²/yr at 210 m depth. The fraction of settling POC attributable to autochthonous processes occurring at or next to ice break-up was estimated to be 75–84% of the 100 m annual fluxes and to be 61-75% of the 210 m fluxes. Over the three ice-reduced seasons, distinct scenarios between ice conditions, surface POC pools and vertical POC export at 100 m were identified: (1) in 2004, despite a normal ice break-up, a weak primary production was measured and low vertical fluxes were collected as old ice moved across the region; (2) in 2005, a lengthened ice-free period allowed an extended season of surface POC production near-shore, while an intermediate increase of vertical fluxes was recorded offshore; and (3) in 2006, a late ice melt gave rise to a pulsed ice edge bloom and to large vertical fluxes also associated with extra ice-flushed material. Linear regressions of vertical POC fluxes against satellite-derived surface POC concentrations suggested that the pelagic POC retention in the upper 100 m of the Amundsen Gulf ranged from ca. 70% to 90% depending on the timing of ice cover melt. Regardless of the inter-annual variability, the estimated fraction of the surface POC reservoir reaching the 210 m water depth was reduced to 5%. Therefore, as the Arctic Ocean warms up, our results support the expectation that the increasing extent of the seasonal ice zone will promote the POC pathways that benefit pelagic webs rather than benthic communities. (Au)

B, D, E, G, H, I, J
Algae; Benthos; Biomass; Bottom sediments; Breakup; Carbon; Carbon cycling; Carbon dioxide; Chlorophyll; Climate change; Food chain; Formation; Hydrography; Marine ecology; Measurement; Melting; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Optical properties; Phytoplankton; Plant nutrition; Primary production (Biology); Remote sensing; Salinity; Satellite photography; Sea ice; Sea water; Seasonal variations; Solar radiation; Surface properties; Suspended solids; Temperature; Temporal variations; Water masses; Winds; Zooplankton

G0815
Amundsen Gulf, N.W.T.


Cases : des chercheurs prennent le pouls de l'océan Arctique enfiévré   /   Fortier, L.
(Météorologie, no 53, mai 2006, p. 38-41, ill., map)
References.
English abstract also provided.
This article is modified from the original published in v. 4, no 2 of Toit du Monde (Iqaluit, Nunavut). It is reprinted with permission.
ASTIS record 67498.
Languages: French
Web: http://documents.irevues.inist.fr/bitstream/2042/20079/1/meteo_2006_53_38.pdf

L'océan Arctique se réchauffe et sa banquise se rétrécit. Quels seront les impacts d'un allongement de la saison libre de glace sur l'écosystème marin arctique et sa faune unique ? Pour répondre à cette question, océanographes, climatologues et géologues joignent leurs forces dans une aventure multidisciplinaire d'une ampleur sans précédent à bord du brise-glace de recherche Amundsen. Pendant plus d'un an, 225 chercheurs de huit pays étudient sur place la réponse de l'écosystème de la mer de Beaufort à la réduction de son couvert de glace. Les premières observations révèlent un monde étonnamment dynamique où des organismes ultraspécialisés et vulnérables respirent, s'entre-dévorent et se reproduisent, même au coeur de la longue nuit polaire. (Au)

E, G, D, J, I, H, R
Algae; Amphipoda; Amundsen (Ship); Arctic cod; ArcticNet Inc.; Atmospheric temperature; Biomass; Breakup; Canadian Arctic Shelf Exchange Study; Carbon; Climate change; Copepoda; Environmental impacts; Food chain; Gases in ice; Ice cover; Icebreakers; Logistics; Marine biology; Melting; Ocean temperature; Ocean-atmosphere interaction; Predation; Research funding; River discharges; Sea ice; Seasonal variations; Socio-economic effects; Stamukhi; Trophic levels; Water masses; Zooplankton

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Inuvik, N.W.T.; Mackenzie River, N.W.T.


Introduction to special section on annual cycles on the Arctic Ocean shelf   /   Fortier, L.   Cochran, J.K.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C3, C03S00, Mar. 2008, 6 p., ill., map)
References.
ASTIS record 64589.
Languages: English
Web: doi:10.1029/2007JC004457
Libraries: ACU

The perennial sea-ice cover of the Arctic Ocean is shrinking rapidly in response to the anthropogenic warming of Earth's lower atmosphere. From September 2002 to September 2004 the Canadian Arctic Shelf Exchange Study (CASES) logged over 14,500 scientist-days at sea to document the potential impacts of a shift in sea-ice regime on the ecosystem of the Mackenzie Shelf in the southeastern Beaufort Sea. In particular, teams from Canada, Denmark, Japan, Norway, Spain, the United Kingdom, and the United States totaling over 200 scientists took rotations on the CCS Amundsen to study all aspects of the ecosystem during a 385-day over-wintering expedition in the region from September 2003 to September 2004. The resulting wealth of information has revealed an unexpectedly active food web under the winter sea ice of the coastal Beaufort Sea. From the thermodynamics of snow to the reconstruction of local paleo-climate, this special section focuses on how sea-ice cover dynamics dictate biological processes and biogeochemical fluxes on and at the margin of the shallow Arctic continental shelf. The highly successful CASES program has initiated ongoing time series of key measurements of the response of the marine ecosystem to change that have been expanded to other Arctic regions through the ArcticNet project and the International Polar Year. (Au)

G, D, E, J, I, H
Biological productivity; Biology; Breakup; Canadian Arctic Shelf Exchange Study; Carbon cycling; Climate change; Environmental impacts; Food chain; Formation; Geochemistry; Ice cover; Marine ecology; Melting; Ocean-atmosphere interaction; Oceanography; Research; Sea ice; Seasonal variations; Snow; Temporal variations

G0815, G07
Amundsen Gulf, N.W.T.; Beaufort Sea; Franklin Bay, N.W.T.


On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES)   /   Fortier, L. [Editor]   Barber, D. [Editor]   Michaud, J. [Editor]
Winnipeg, Man. : Aboriginal Issues Press, 2008.
vii, 215 p. : ill., maps ; 23 x 29 cm.
ISBN 978-0-9738342-6-0
Appendix.
References.
ASTIS record 67474.
Languages: English
Libraries: ACU

The Arctic is on its way to new climatic equilibrium. Perennial sea ice, permafrost and glaciers are vanishing at unexpected rates. Combined with rampant modernization, warming has profound impacts on the geopolitics, economy, health and societies of the Canadian Arctic. The Canadian Arctic Shelf Exchange Study (CASES) represents the largest single effort ever to understand the response of the Arctic Ocean biota to climate change. Over a complete annual cycle, 210 scientists from 8 countries studied all aspects of the Beaufort Sea ecosystem. This compendium summarizes their findings in a form relevant to policy makers, community members, and managers. (Au)

D, G, E, F, J, I, H, A, B, Y, L, R
Animal distribution; Animal respiration; Benthos; Biological productivity; Biomass; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chlorophyll; Climate change; Cores; Environmental impacts; Food chain; Ice cover; Ice leads; Light; Marine biology; Marine fauna; Marine flora; Mathematical models; Microbial ecology; Ocean-atmosphere interaction; Oceanography; Palaeoclimatology; Photosynthesis; Plankton; Plant distribution; Plant growth; Plant nutrition; Polynyas; Remote sensing; River discharges; Salinity; Sea ice; Seasonal variations; Sediment transport; Sedimentation; Snow; Spatial distribution; Stamukhi; Storms; Suspended solids; Temperature; Temporal variations; Water masses; Winds

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.


An introduction to the Canadian Arctic Shelf Exchange Study   /   Fortier, L.   Barber, D.G.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 1, p. 1-11, ill., map
References.
ASTIS record 67475.
Languages: English
Libraries: ACU

... The planning of the Canadian Arctic Shelf Exchange Study (CASES) in 2000 was motivated by the notion that the warming of Earth's climate anticipated by climatologists would begin and be most intense at arctic latitudes. ... The field program proposed by CASES was designed to contrast the annual cycle of the arctic marine ecosystem in three regions: (1) the Cape Bathurst polynya; (2) the Mackenzie Shelf and (3) the edge and slope of the Shelf .... Overall, the CASES field program logged 543 days at sea, 377 of these days being directly chartered by CASES and 166 being contributed by national and international partners. This corresponded to a total of 14 544 day-scientists at sea, which makes the CASES field program the largest and most comprehensive international effort thus far to decipher the functioning of the Arctic Ocean shelf ecosystem and understand the biogeochemical and ecological impacts of the present decline in arctic sea ice cover. ... This synthesis of the CASES research activities reviews and highlights the scientific conclusions that emerged from the extensive data sets collected and analyzed by each subproject during the program. Each chapter introduces in a general way the rationale of the subproject; provides an overview of the key findings along with scientific references for further reading; details the implication of the work; and finally makes recommendations on the future research and policies. ... Chapter 2 describes an overview of the seasonal circulation on the Beaufort Shelf. ... The complex changes at the Ocean-Sea Ice-Atmosphere interface in the CASES study area are described in Chapter 3. ... Chapter 4 investigates the dynamics of light, nutrients and microalgae in ice-covered and ice-free waters of the Beaufort Sea throughout the year. ... Microbial communities and carbon fluxes is the main topic of Chapter 5. ... Chapter 6 investigates the pelagic food web structure and function, as well as contaminants in relation to climate change and ice cover dynamics. ... Chapter 7 presents data on organic and inorganic fluxes in the Beaufort Sea and the Mackenzie shelf. ... Chapter 8 focused on the calibration and the use of proxies for revealing the historical variability in paleoclimates in the CASES study area. ... Benthic communities of the Arctic shelf, presented in Chapter 9, play an important role in the cycling of carbon and the recycling of nutriment but are not always well known. ... Finally, Chapter 10 presents the data management and archiving strategy adopted by the Network to ensure that CASES data are preserved and accessible to all. ... (Au)

E, D, G, F, J, I, H, B, Y, R, L
Amundsen (Ship); Archives; Atmosphere; Benthos; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Climate change; Climatology; Databases; Education; Environmental impacts; Fast ice; Food chain; Geochemistry; Hydrology; Ice cover; Ice leads; Icebreakers; Light; Logistics; Marine biology; Melting; Microbial ecology; Ocean currents; Ocean-atmosphere interaction; Oceanographic instruments; Oceanography; Pack ice; Palaeoclimatology; Phytoplankton; Plant nutrition; Polynyas; Primary production (Biology); Research funding; River discharges; Scientists; Sea ice; Seasonal variations; Sediment transport; Sedimentation; Snow; Spatial distribution; Stamukhi; Temperature; Temporal variations; Water masses; Winds

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie Trough, Canadian Beaufort Sea


CASES - Canadian Arctic Shelf Exchange Study : CASES2002 cruise report & preliminary data report, 20 September to 14 October 2002 expedition onboard the CCGS Pierre Radisson   /   Fortier, M. [Editor]
Québec, Québec : Université Laval, 2002.
73 p. : ill., maps ; 28 cm.
Appendices.
Cover title.
Running title: CASES2002 cruise report & preliminary data report.
Indexed a PDF file from the Web.
References.
ASTIS record 74421.
Languages: English
Web: http://www.quebec-ocean.ulaval.ca/cases/Radisson2002report.pdf

Introduction: The extent and thickness of Arctic sea ice vary considerably from year to year and over decadal time scales. Assessing the effects of present variability in sea ice cover on Arctic marine ecosystems and regional climate requires a substantial improvement in our understanding of the links between freshwater and sea ice, sea ice and climate, and sea ice and biogeochemical fluxes. The need for data is particularly strong for the shallow coastal shelf regions (30% of the Arctic basin) where variability in the extent, thickness and duration of sea ice is most pronounced and where Arctic marine food webs are most vulnerable to change. Toward that goal, the CASES Research Network was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) to conduct the Canadian Arctic Shelf Exchange Study (CASES), an international effort under Canadian leadership to understand the biogeochemical and ecological consequences of sea ice variability and change on the Mackenzie Shelf/Amundsen Gulf area. A central aim of the CASES field program is to study the fall and winter pre-conditioning of the Mackenzie Shelf/Amundsen Gulf ecosystem by the minimum fall and winter discharge of the Mackenzie River, and its spring and summer development in response to the intense freshet and the variable ice break-up. Because the area cannot be reached from southern ports until August when the ice retreats, the only possible way to achieve this is by over-wintering a research icebreaker in the area. In preparation for the 2003-2004 over-wintering expedition, two expeditions were conducted in the fall of 2002 to 1) deploy 8 mooring arrays supporting current meters and sediment traps and 2) conduct a synoptic survey of the physical & biogeochemical properties of the study area at the end of the primary production season. The mooring component of CASES2002 was completed during the 6 September to 24 September expedition of the CCGS Sir Wilfrid Laurier to the study area. A detailed cruise report for this expedition is available on the CASES website at (http://www.cases.quebec-ocean.ulaval.ca/fieldwor.asp). The present document mostly reports on the physical & biogeochemical survey of the study area conducted during the 22 September to 14 October expedition of the CCGS Pierre Radisson. CASES general objectives: Based on the general hypothesis that the atmospheric, oceanic and hydrologic forcing of sea ice variability dictates the nature and magnitude of biogeochemical carbon fluxes on and at the edge of the Mackenzie Shelf, the major objectives of the CASES program are to assess: - The role of hydrologic, oceanographic and meteorological processes in ice accretion, ablation and transport on the shelf and beyond; - The hydrodynamic (including ice and snow cover dynamics) control of Arctic shelf photosynthetic production and its exportation to the benthos and the pelagic food web; - The potential impact of increased UV radiation on biological productivity; - The role of microheterotrophs and mesozooplankton in transforming autochthonous and allochthonous particulate and dissolved matter on the shelf; - The fluxes of particulate matter and carbon across the shelf to the deep basins; - The distribution of riverine and air-borne contaminants in the trophic web; - The potential impact of a reduction in ice habitat on birds and marine mammals; - The decadal and millennial variations in ice cover and their impact on ecosystem productivity. Physical and biological measurements will also be used to constrain and calibrate: - Regional models of climate and ice dynamics in the western Canadian Arctic; - Biophysical models of the carbon flows on the Canadian Arctic shelf. ... (Au)

D, G, E, B, H, I, J, L
Animal food; Benthos; Biological sampling; Birds; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chemical oceanography; Climate change; Data buoys; Effects of ice on climate; Environmental impacts; Equipment and supplies; Fishes; Food chain; Geochemistry; Hydrography; Ice cover; Ice shelves; Instruments; Light; Marine ecology; Marine mammals; Measurement; Meteorology; Microbial ecology; Ocean temperature; Ocean waves; Ocean-atmosphere interaction; Phytoplankton; Pierre Radisson (Ship); Pollution; Primary production (Biology); River discharges; Salinity; Sea ice; Sea ice ecology; Seasonal variations; Sonar; Suspended solids; Temporal variations; Viruses; Water masses; Zooplankton

G07, G0812, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Coronation Gulf, Nunavut; Franklin Bay, N.W.T.; Franklin Strait, Nunavut; Kugmallit Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.; Tuktoyaktuk waters, N.W.T.


Canadian-led international research in the changing coastal Canadian Arctic   /   Fortier, M.   Fortier, L.
(Canada's Arctic : vast, unexplored and in demand. The journal of ocean technology (St. John's, N.L.), v. 1, no. 1, Summer 2006, p. 1-7, ill.)
References.
ASTIS record 65905.
Languages: English

... In Canada, climate warming will have tremendous environmental, socio-economic and strategic consequences that will be felt first and most severely in Arctic communities and territories. ... From a geopolitical viewpoint, the anticipated continued reduction of the Arctic sea-ice cover could virtually open a new ocean .... Canada's sovereignty over the channels of the Canadian Archipelago has been repeatedly challenged in the past and the new geopolitical hand dealt by an eventual opening of the Northwest Passage would renew these assaults .... In 1958, the Department of Natural Resources Canada established the Polar Continental Shelf Project (PCSP) to support Canadian and international research in the Canadian Arctic. ... despite obvious Arctic responsibilities and the mounting urgency of monitoring a warming Arctic, Canada's northern scientific program generally stagnated and dwindled over the 1980s and 1990s. ... Responding to the decline of Canadian research in the North, the Natural Sciences and Engineering Research Council (NSERC) and the Social Sciences and Humanities Research Council (SSHRC) established a joint Task Force on Northern Research in 1998. The report of the Task Force entitled "From Crisis to Opportunity: Rebuilding Canada's Role in Northern Research" ... confirmed that Canadian northern research was in crisis .... the report concluded that "the NSERC-funded International North Water Polynya Study (NOW) project (1997-2001) was the only major international northern research project to be led by a Canadian university group in recent years." One of the worst symptoms of this crisis was the sharp decline in Canadian northern research capacity. ... the Task Force Report clearly identified the want of a dedicated research icebreaker as a major obstacle to the development of the multidisciplinary Canadian-led international program that would be commensurate with Canada's responsibilities in the Arctic. In 2001, a Research Consortium of 34 university-based researchers from across Canada and their collaborators in 12 Federal research institutes joined forces with the objective of solving the issue. ... the Consortium was successful in obtaining a $27.5M grant from the Canada Foundation for Innovation (CFI) to transform a de-commissioned Canadian Coast Guard icebreaker into a dedicated research platform for the international study of the changing coastal Canadian Arctic. ... Since its inauguration in August 2003, the Amundsen has been a major catalyst in re-energizing Canada's Arctic effort by providing Canadian researchers and their international collaborators with unprecedented access to the coastal Arctic. The first research program supported by the Amundsen [funded by NSERC] was the Canadian Arctic Shelf Exchange Study (CASES, 2002-2007). ... the Research Consortium of the Amundsen announced as early as 2001 that it would join forces with human health and social science specialists to propose ArcticNet, the first Arctic Network of Centres of Excellence of Canada. Funded in 2004 at a level of $6.4M per year until 2011 (renewable until 2018), ArcticNet (www.arcticnet.ulaval.ca) connects several well-established centres of excellence in Arctic research. ... The central objective of ArcticNet is to generate the knowledge and assessments needed to formulate the adaptation strategies and policies that will help northern societies and industries prepare for the anticipated transformation of the Arctic. ... The type of science initiated by ArcticNet to address concerns raised by climate change and modernization in the Canadian Arctic is expected to receive a major boost from the upcoming International Polar Year (IPY). ... Highly successful Canadian-led projects such as NOW, CASES, the Amundsen and ArcticNet, have allowed Canada to take back the leadership of the international research effort conducted in its own Arctic waters. The benefits for Canada of a strong Canadian-led international research program are far-reaching. ... (Au)

R, E, J, T, D, G
Acclimatization; Amundsen (Ship); ArcticNet Inc.; Canadian Arctic Shelf Exchange Study; Climate change; Coast changes; Environmental impacts; Government; Higher education; International North Water Polynya Study; Inuit; Melting; Polar Continental Shelf Project (Canada); Research; Research funding; Scientists; Sea ice; Socio-economic effects; Sovereignty; Universities

G081
Canadian Arctic; Canadian Arctic waters


University-led Arctic research programs in Canada   /   Fortier, M.
In: Proceedings : United States and Canada Northern Oil and Gas Research Forum : current status and future directions in the Beaufort Sea, North Slope and Mackenzie Delta, in Anchorage, Alaska, 28-30 October 2008. - Calgary, Alta. : Golder Associates, 2008, presentation 5.1.8, [16] p., ill., maps
Indexed a PDF file from a CD-ROM.
Title of the presentation taken from the first Microsoft PowerPoint slide.
The presentation consists of 59 Microsoft PowerPoint slides.
Also available from the Web.
ASTIS record 68954.
Languages: English
Web: http://quickr.mtri.org/servlet/QuickrSupportUtil?type=quickrdownload&key=/LotusQuickr/nssi/PageLibrary852574F60068C90D.nsf/0/78D2F136955504A0852574F6006A1EF1/$file/US-Can_Northern_Oil_and_Gas_Research_Forum_2008_Proceedings.pdf
Libraries: ACU

Since 2002, our University-led Arctic Research Consortium has received investments of over 120 million dollars by the Government of Canada, in of support Canadian-led, international efforts to study the changing Canadian Arctic. 1. Canadian Research icebreaker Amundsen (CFI-DFO/CG): 30 million (2003-). 2. Canadian Arctic Shelf Exchange Study (NSERC): 10.6 million (2002-2007). 3. ArcticNet (NCE): 25.7 million for 7 years (2004-2011), potential for 14 years (2004-2018). 4. Scientific Equipment for Amundsen (CFI, Gvt of Quebec, Gvt of Manitoba): 10.9 million (2006- ). 5. International Polar Year (30-50 million): (2007-2009). ... In conclusion: The long term nature and structure of ArcticNet offers tremendous challenges/opportunities. Opportunity to: [1] break barriers between research sectors, [2] work in real and meaningful partnership with Northerners in the full research process, [3] work in partnership with stakeholders and industry, [4] start long term monitoring (14 years), [5] consolidate international Arctic collaborations, [6] help maintain an IPY legacy, [7] contribute to adaptation policies. (Au)

D, J, L, R, T, E, B, K, G
Amundsen (Ship); ArcticNet Inc.; Bottom sediments; Canadian Arctic Shelf Exchange Study; Climate change; Education; Environmental impacts; Equipment and supplies; Health; Ice leads; Icebreakers; Inuit; Management; Marine ecology; Oceanography; Public participation; Research funding; Research stations; Sea ice; Sonar; Universities

G07, G0815, G0814, G09, G0813, G0826, G0812
Amundsen Gulf, N.W.T.; Baffin Bay-Davis Strait; Canadian Arctic Islands waters; Canadian Beaufort Sea; Hudson Bay; Labrador; Mackenzie Delta, N.W.T.; Nunavik, Québec; Nunavut


Remarkably diverse and contrasting archaeal communities in a large Arctic river and the coastal Arctic Ocean   /   Galand, P.E.   Lovejoy, C.   Vincent, W.F.
(Aquatic microbial ecology, v. 44, no. 2, Sept. 2006, p. 115-126, ill., maps)
References.
ASTIS record 62004.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/195.pdf
Web: doi:10.3354/ame044115
Libraries: NSHD

Although the microbial biodiversity of arctic seas has received an increasing amount of attention, little is known about the microbial communities of its inflowing rivers. In this study we examined the molecular diversity of Archaea in the largest arctic river in North America, the Mackenzie River, and in the adjacent coastal Beaufort Sea (Canadian Arctic) during maximum open water conditions (October 2002). The Mackenzie River 16S rRNA clone libraries revealed a remarkably diverse assemblage of archaeal sequences, with an estimated 286 phylotypes defined as sequences with 97% similarity. These grouped mainly within 2 phylogenetic clusters, and were related to sequences earlier retrieved from flooded soils and sediments previously named RC-V and LDS. The marine coastal libraries were of very different composition to those of river libraries and were dominated by Group II Euryarchaeota followed by Group I Crenarchaeota. These coastal assemblages had greater archaeal diversity (18 to 23 phylotypes) than previously reported for marine communities elsewhere, and differed from previously described central Arctic Ocean assemblages. This may reflect the heterogeneous mixture of organic substrates and particles available for microbial heterotrophy in arctic coastal waters and the use of an alternative primer pair (109f-915r) in this study. The coastal sequences grouped within typical marine clusters, and we therefore conclude that they were an active autochthonous community rather than one derived from the large inflowing river. These results underscore the rich microbial diversity in arctic rivers and their adjacent coastal marine ecosystems. (Au)

I, H, J, D, F, C
Animal distribution; Archaea; Biological sampling; Biomass; Carbon; Chlorophyll; Fluorometry; Fresh-water biology; Genetics; Logistics; Marine biology; Measurement; Ocean temperature; Phytoplankton; River discharges; Salinity; Size; Soil microorganisms; Soils; Suspended solids; Temperature; Watersheds

G07, G0812
Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Kugmallit Bay, N.W.T.; Middle Channel (Mackenzie River), N.W.T.


Microbial community diversity and heterotrophic production in a coastal Arctic ecosystem : a stamukhi lake and its source waters   /   Galand, P.E.   Lovejoy, C.   Pouliot, J.   Garneau, M.-È.   Vincent, W.F.
(Limnology and oceanography, v. 53, no. 2, Mar. 2008, p. 813-823, ill., maps)
References.
ASTIS record 64583.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/224.pdf
Libraries: ACU

Stamukhi lakes are vast but little-explored Arctic ecosystems. They occur throughout winter, spring, and early summer near large river inflows along the Arctic coastline, and are the result of freshwater retention behind the thick barrier of rubble ice (stamukhi) that forms at the outer limit of land-fast sea ice. We examined the molecular biodiversity within all three microbial domains (Bacteria, Archaea, and Eukaryota) and the heterotrophic productivity in Lake Mackenzie, a stamukhi lake in the western Canadian Arctic, and made comparative measurements in the freshwater (Mackenzie River) and marine (Beaufort Sea) source waters. Bacterial and eukaryotic communities in the stamukhi lake differed in composition and diversity from both marine and riverine environments, whereas the archaeal communities were similar in the lake and river. Bacteria 16S ribosomal RNA sequences from the lake were mostly within freshwater clusters of Betaproteobacteria and Bacteroidetes and the Archaea were within the Lake Dagow sediment and Rice cluster-V clusters of Euryarchaeota. The eukaryotes were mainly ciliates from the subclass Choreotrichia, and there was a notable lack of flagellates. Heterotrophic production rates in the lake were lower than in the river and more similar to those in the sea, despite much higher bacterial concentrations than in either. The lake samples had markedly higher ratios of 3H leucine to 3H thymidine incorporation than in the river and sea, implying some physiological stress. Lake Mackenzie is an active microbial ecosystem with distinct physical and microbiological properties. This circumpolar ecosystem type, vulnerable to the ongoing effects of climate change, likely plays a key functional role in processing riverine inputs to the Arctic Ocean. (Au)

H, I, D, F, G, A, E, J
Archaea; Bacteria; Biological productivity; Breakup; Carbon cycling; Chlorophyll; Climate change; Coasts; Dinoflagellata; Effects of climate on ice; Estuaries; Estuarine ecology; Fast ice; Formation; Heterotrophic bacteria; Ice cover; Ice rubble fields; Ice scouring; Lagoons; Lake ice; Marine biology; Melting; Microbial ecology; Ocean temperature; Phytoplankton; Primary production (Biology); River discharges; River ice; Salinity; Sea ice; Sea ice ecology; Sediment transport; Stamukhi; Suspended solids

G0812, G07
Canadian Beaufort Sea; Mackenzie River, N.W.T.


Heterogeneous archaeal communities in the particle-rich environment of an Arctic shelf ecosystem   /   Galand, P.E.   Lovejoy, C.   Pouliot, J.   Vincent, W.F.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 774-782, ill., maps)
References.
ASTIS record 65250.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/226.pdf
Web: doi:10.1016/j.jmarsys.2007.12.001
Libraries: ACU

We evaluated the phylogenetic diversity of particle-associated and free-living archaeal assemblages from the Mackenzie River and Beaufort Sea in the western Canadian Arctic. The physico-chemical characteristics of the water separated the sampling sites into three groups: riverine, coastal and marine water, which had strikingly different archaeal communities. The riverine water was characterised by the presence of Euryarchaeota mainly belonging to the LDS and RC-V clusters. The coastal water was also dominated by Euryarchaeota but they were mostly affiliated to Group II.a. The marine waters contained most exclusively Crenarchaeota belonging to the Marine Group I.1a. The results suggest that Euryarchaeota in the coastal surface layer are associated with particle-rich waters, while Crenarchaeota are more characteristic of Arctic Ocean waters that have been less influenced by riverine inputs. The particle-associated communities were similar to the free-living ones at the riverine and marine sites but differed from each other at the coastal site in terms of the presence or absence of some taxonomic groups in one of the fractions, or differences in the proportion of the phylogenetic groups. However, there was no specific archaeal group that was exclusively restricted to the free-living or particle fraction, and the diversity of the particle-associated archaeal assemblages did not significantly differ from the diversity of the free-living communities. (Au)

H, I, J, F, D
Animal distribution; Bacteria; Biological sampling; Biomass; Carbon; Chlorophyll; Classification; Estuarine ecology; Fluorometry; Fresh-water ecology; Genetics; Marine ecology; Microbial ecology; Microorganisms; Ocean temperature; Plankton; Plant distribution; River discharges; Rivers; Salinity; Sea water; Suspended solids; Temperature

G0812, G07
Dalhousie, Cape, waters, N.W.T.; Kugmallit Bay, N.W.T.; Middle Channel (Mackenzie River), N.W.T.


Unique archaeal assemblages in the Arctic Ocean unveiled by massively parallel tag sequencing   /   Galand, P.E.   Casamayor, E.O.   Kirchman, D.L.   Potvin, M.   Lovejoy, C.
(The ISME journal, v. 3, no. 7, July 2009, p. 860-869, ill., maps)
References.
This is a contribution to the International Census of Marine Microbes (ICOMM).
ASTIS record 68567.
Languages: English
Web: doi:10.1038/ismej.2009.23
Libraries: ACU

The Arctic Ocean plays a critical role in controlling nutrient budgets between the Pacific and Atlantic Ocean. Archaea are key players in the nitrogen cycle and in cycling nutrients, but their community composition has been little studied in the Arctic Ocean. Here, we characterize archaeal assemblages from surface and deep Arctic water masses using massively parallel tag sequencing of the V6 region of the 16S rRNA gene. This approach gave a very high coverage of the natural communities, allowing a precise description of archaeal assemblages. This first taxonomic description of archaeal communities by tag sequencing reported so far shows that it is possible to assign an identity below phylum level to most (95%) of the archaeal V6 tags, and shows that tag sequencing is a powerful tool for resolving the diversity and distribution of specific microbes in the environment. Marine group I Crenarchaeota was overall the most abundant group in the Arctic Ocean and comprised between 27% and 63% of all tags. Group III Euryarchaeota were more abundant in deep-water masses and represented the largest archaeal group in the deep Atlantic layer of the central Arctic Ocean. Coastal surface waters, in turn, harbored more group II Euryarchaeota. Moreover, group II sequences that dominated surface waters were different from the group II sequences detected in deep waters, suggesting functional differences in closely related groups. Our results unveiled for the first time an archaeal community dominated by group III Euryarchaeota and show biogeographical traits for marine Arctic Archaea. (Au)

D, H, I, J
Animal distribution; Archaea; Bathymetry; Biological productivity; Biological sampling; Carbon cycling; Chemical oceanography; Fluorometry; Genetics; Geochemistry; Marine ecology; Microbial ecology; Nitrogen; Nitrogen cycling; Phytoplankton; Plant distribution; Plant taxonomy; Primary production (Biology); Sea water; Water masses

G03, G05, G07, G0815, G09, G04
Amundsen Gulf, N.W.T.; Arctic Ocean; Baffin Bay-Davis Strait; Bering Strait; Canada Basin, Arctic Ocean; Canadian Arctic Islands waters; Canadian Beaufort Sea; Chukchi Sea; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.; North Atlantic Ocean; North Pacific Ocean; Norwegian Sea


Spatial and temporal variability of sea ice in the southern Beaufort Sea and Amundsen Gulf : 1980-2004   /   Galley, R.J.   Key, E.   Barber, D.G.   Hwang, B.J.   Ehn, J.K.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C5, C05S95, May 2008, 18 p., ill., maps)
References.
ASTIS record 64590.
Languages: English
Web: doi:10.1029/2007JC004553
Libraries: ACU

Changing extent, location, and motion of the Arctic perennial pack affect the annual evolution of seasonal ice zones. Canadian Ice Service digital ice charts covering the southern Beaufort Sea and Amundsen Gulf are used to illustrate summer and winter conditions and trends between 1980 and 2004 for several sea ice stages of development. Results illustrate average sea ice conditions within the region in summer and winter for predominant sea ice types and changes in the relative concentration of sea ice types in summer and winter. In summer, a trend toward increased old sea ice concentration occurred near the mouth of Amundsen Gulf, with a trend toward decreasing summer first-year sea ice farther west. In winter, increasing thick first-year sea ice extent appears to be replacing young sea ice within the flaw lead system in the region. The dynamically driven breakup of sea ice in spring in the Amundsen Gulf is a highly variable event taking anywhere between 2 and 22 weeks to completely remove ice from the gulf. The timing and duration of the open water season depends upon the extent and timing of old ice influx. Freezeup occurs very quickly, proceeding from west to east with little temporal variability. The results of this paper are used to set the context for the Canadian Arctic Shelf Exchange Study (CASES) in terms of sea ice dynamic and thermodynamic processes. (Au)

G, E, A
Atmospheric pressure; Atmospheric temperature; Breakup; Climate change; Databases; Effects of climate on ice; Electronic data processing; Formation; Growth; Ice cover; Ice floes; Ice leads; Infrared remote sensing; Mapping; Maps; Melting; Movement; Pack ice; SAR; Satellites; Sea ice; Seasonal variations; Spatial distribution; Temporal variations; Thickness

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Sea ice thermodynamic and dynamic processes in the ocean-sea ice-atmosphere system of the Canadian Arctic   /   Galley, R.J.   Barber, D. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2009.
xiii, 252 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR64245)
ISBN 978-0-494-64245-0
Thesis (Ph.D.) - University of Manitoba, Winnipeg, Man., 2009.
Appendices.
References.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74748.
Languages: English
Libraries: MWU

Sea ice, by its presence or absence, controls the transfer of energy, mass and momentum between the ocean and atmosphere in the Arctic playing a vital role in the modulation of earth's climate systems. Polynyas are of particular importance in to ocean-atmosphere exchange in the Arctic because they are integral components of the physical and biological nature of the Arctic climate. The aim of this thesis is to investigate snow-covered sea ice volumes from the local to regional scale in the context of thermodynamic and dynamic processes that create them and cause their interaction. Measurement of separate snow and sea ice thickness has in the past been of some difficulty, especially when attempting to obtain spatially distributed samples. Using snow and sea ice physical in situ sampling, a method for remotely sensing separate snow and sea ice thickness using ground penetrating radar has been created to allow for high frequency sampling in time and space. The effect of a melting sea ice volume on ocean stratification is then examined in a Canadian Arctic polynya, where it is determined that the onset of ponding over landfast sea ice surrounding the polynya coincides with the summer stratification of the upper ocean mixed layer. Increasing in scale from local to regional study, the interaction of different sea ice volumes in time and space are examined, including the spatial and temporal evolution and trends of sea ice concentration. Break-up and freeze-up in the Cape Bathurst polynya region are examined to elucidate the variability of break-up and freeze-up in Amundsen Gulf in terms of regional dynamics and the evolving , seasonal ice cover in the area. This work leads to an explanation of the thermodynamic and dynamic processes that cause the interaction of volumes in the region over an annual cycle; physical mechanisms that pre-condition, form and maintain the Cape Bathurst polynya. This is an important step in understanding the nature of atmosphere-ocean interaction in an ecologically important transition zone between the Arctic multi-year pack and seasonal sea ice of the Canadian Arctic Archipelago. (Au)

G, E, D, F
Albedo; Atmosphere; Atmospheric circulation; Atmospheric pressure; Atmospheric temperature; Breakup; Climate change; Clouds; Deformation; Density; Effects of climate on ice; Energy budgets; Fast ice; Formation; Ground penetrating radar; Ice cover; Ice leads; Mathematical models; Ocean currents; Ocean-atmosphere interaction; Optical properties; Pack ice; Physical properties; Polynyas; Remote sensing; Salinity; Satellites; Sea ice; Seasonal variations; Shear zones (Ice); Size; Snow; Solar radiation; Spatial distribution; Storms; Surface properties; Temperature; Temporal variations; Thermal properties; Thermodynamics; Theses; Thickness; Velocity; Water masses; Winds

G07, G0815, G0814
Amundsen Gulf, N.W.T.; Button Bay, Nunavut; Canadian Beaufort Sea; Churchill Estuary, Manitoba


Mineralogical, geochemical and magnetic signatures of surface sediments from the Canadian Beaufort Shelf and Amundsen Gulf (Canadian Arctic)   /   Gamboa, A.   Montero-Serrano, J.-C.   St-Onge, G.   Rochon, A.   Desiage, P.-A.
(Geochemistry, geophysics, geosystems, v. 18, no. 2, Feb. 2017, p. 488-512, ill., maps)
References.
ASTIS record 82862.
Languages: English
Web: doi:10.1002/2016GC006477
Libraries: ACU

Mineralogical, geochemical, magnetic, and siliciclastic grain-size signatures of 34 surface sediment samples from the Mackenzie-Beaufort Sea Slope and Amundsen Gulf were studied in order to better constrain the redox status, detrital particle provenance, and sediment dynamics in the western Canadian Arctic. Redox-sensitive elements (Mn, Fe, V, Cr, Zn) indicate that modern sedimentary deposition within the Mackenzie-Beaufort Sea Slope and Amundsen Gulf took place under oxic bottom-water conditions, with more turbulent mixing conditions and thus a well-oxygenated water column prevailing within the Amundsen Gulf. The analytical data obtained, combined with multivariate statistical (notably, principal component and fuzzy c-means clustering analyses) and spatial analyses, allowed the division of the study area into four provinces with distinct sedimentary compositions: (1) the Mackenzie Trough-Canadian Beaufort Shelf with high phyllosilicate-Fe oxide-magnetite and Al-K-Ti-Fe-Cr-V-Zn-P contents; (2) Southwestern Banks Island, characterized by high dolomite-K-feldspar and Ca-Mg-LOI contents; (3) the Central Amundsen Gulf, a transitional zone typified by intermediate phyllosilicate-magnetite-K-feldspar-dolomite and Al-K-Ti-Fe-Mn-V-Zn-Sr-Ca-Mg-LOI contents; and (4) mud volcanoes on the Canadian Beaufort Shelf distinguished by poorly sorted coarse-silt with high quartz-plagioclase-authigenic carbonate and Si-Zr contents, as well as high magnetic susceptibility. Our results also confirm that the present-day sedimentary dynamics on the Canadian Beaufort Shelf is mainly controlled by sediment supply from the Mackenzie River. Overall, these insights provide a basis for future studies using mineralogical, geochemical, and magnetic signatures of Canadian Arctic sediments in order to reconstruct past variations in sediment inputs and transport pathways related to late Quaternary climate and oceanographic changes. (Au)

B, D, J
Bottom sediments; Geochemistry; Magnetic properties; Marine geology; Minerals; Mud volcanoes; Ocean currents; Sediment transport; Sedimentation; Sediments (Geology); Silicates; Silt; Spatial distribution; Suspended solids

G07, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Prokaryotic community structure and heterotrophic production in a river-influenced coastal Arctic ecosystem   /   Garneau, M.-È.   Vincent, W.F.   Alonso-Sáez, L.   Gratton, Y.   Lovejoy, C.
(Aquatic microbial ecology, v. 42, no. 1, Feb. 2006, p. 27-40, ill., 1 map)
References.
ASTIS record 62002.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/189.pdf
Web: doi:10.3354/ame042027
Libraries: NSHD

Spatial patterns in prokaryotic biodiversity and production were assessed in the Mackenzie shelf region of the Beaufort Sea during open-water conditions. The sampling transect extended 350 km northwards, from upstream freshwater sites in the Mackenzie River to coastal and offshore sites, towards the edge of the perennial arctic ice pack. The analyses revealed strong gradients in community structure and prokaryotic cell concentrations, both of which correlated with salinity. Picocyanobacterial abundance was low (10**2 to 10**3 cells/ml), particularly at the offshore stations that were least influenced by the river plume. Analysis by catalyzed reporter deposition for fluorescence in situ hybridization (CARD-FISH) showed that the dominant heterotrophic cell types were ß-Proteobacteria at river sites, shifting to dominance by alpha-Proteobacteria offshore. Cells in the Cytophaga-Flavobacter-Bacteroides and gamma-Proteobacteria groups each contributed <5% of total counts in the river, but >10% of counts in the marine samples. Archaea were detected among the surface-water microbiota, contributing on average 1.3% of the total DAPI counts in marine samples, but 6.0% in turbid coastal and riverine waters. 3H-leucine uptake rates were significantly higher at 2 stations influenced by the river (1.5 pmol/l/h) than at other marine stations or in the river itself (<=0.5 pmol/1/h). Size-fractionation experiments at 2 coastal sites showed that >65% of heterotrophic production was associated with particles >3 µm. These results indicate the importance of particle-attached prokaryotes, and imply a broad functional diversity of heterotrophic microbes that likely facilitates breakdown of the heterogeneous dissolved and particulate terrestrial materials discharged into arctic seas (Au)

I, H, J, D, F
Animal distribution; Archaea; Bacteria; Biological productivity; Biological sampling; Biomass; Carbon; Chlorophyll; Cyanophyceae; Fluorometry; Fresh-water biology; Logistics; Marine biology; Measurement; Microorganisms; Ocean temperature; Phytoplankton; Plant distribution; River discharges; Salinity; Size; Spatial distribution; Spectroscopy; Stream flow; Suspended solids; Temperature

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Franklin Bay, N.W.T.; Kugmallit Bay, N.W.T.; Middle Channel (Mackenzie River), N.W.T.


Seasonal dynamics of bacterial biomass and production in a coastal Arctic ecosystem : Franklin Bay, western Canadian Arctic   /   Garneau, M.-È.   Roy, S.   Lovejoy, C.   Gratton, Y.   Vincent, W.F.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C7, C07S91, July 2008, 15 p., ill.)
References.
ASTIS record 65011.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/240.pdf
Web: doi:10.1029/2007JC004281
Libraries: ACU

The Canadian Arctic Shelf Exchange Study (CASES) included the overwintering deployment of a research platform in Franklin Bay (70°N, 126°W) and provided a unique seasonal record of bacterial dynamics in a coastal region of the Arctic Ocean. Our objectives were (1) to relate seasonal bacterial abundance (BA) and production (BP) to physico-chemical characteristics and (2) to quantify the annual bacterial carbon flux. BA was estimated by epifluorescence microscopy and BP was estimated from 3H-leucine and 3H-thymidine assays. Mean BA values for the water column ranged from 1.0 (December) to 6.8 × 10**5 cells/mL (July). Integral BP varied from 1 (February) to 80 mg C/m²/d (July). During winter-spring, BP was uncorrelated with chlorophyll a (Chl a), but these variables were significantly correlated during summer-autumn (rs = 0.68, p < 0.001, N = 38), suggesting that BP was subject to bottom-up control by carbon supply. Integrated BP data showed three distinct periods: fall-winter, late winter-late spring, and summer. A baseline level of BB and BP was maintained throughout late winter-late spring despite the persistent cold and darkness, with irregular fluctuations that may be related to hydrodynamic events. During this period, BP rates were correlated with colored dissolved organic matter (CDOM) but not Chl a (rs BP.CDOM/Chl a = 0.20, p < 0.05, N = 176). Annual BP was estimated as 6 g C/m²/a, implying a total BP of 4.8 × 10**10 g C/a for the Franklin Bay region. These results show that bacterial processes continue throughout all seasons and make a large contribution to the total biological carbon flux in this coastal arctic ecosystem. (Au)

J, H, I, D, G, A
Animal distribution; Bacteria; Biological productivity; Biological sampling; Biomass; Carbon cycling; Chlorophyll; Colored dissolved organic matter; Continental shelves; Density; Fluorometry; Marine ecology; Measurement; Microbial ecology; Microorganisms; Ocean temperature; Photosynthesis; Phytoplankton; Plant distribution; Primary production (Biology); Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Solar radiation; Spectroscopy; Thickness; Water masses; Winter ecology

G07, G01
Franklin Bay, N.W.T.; Polar regions


Structure et dynamique du réseau microbien dans des écosystèmes côtiers arctiques sous l'influence d'apports riverains   /   Garneau, M.-È.   Vincent, W.F. [Supervisor]
Québec, Québec : Université Laval, 2008.
xiv, 147 p. : ill., maps ; 28 cm.
Thesis (Ph.D.) - Université Laval, Québec, Québec, 2008.
Indexed a PDF file from the Web.
References.
Contents: Chapitre 1: Introduction génerale - Chapitre 2: Prokaryotic community structure and heterotrophic production in a river-influenced coastal Arctic ecosystem / Marie-Eve Garneau, Warwick F. Vincent, Laura Alonso-Sâez, Yves Gratton, Connie Lovejoy, publié dans Aquatic Microbial Ecology (2006) 42:27-40 - Chapitre 3: Seasonal dynamics of bacterial biomass and production in a coastal Arctic ecosystem: Franklin Bay, western Canadian Arctic / Marie-Eve Garneau, Sébastien Roy, Connie Lovejoy, Yves Gratton, Warwick F. Vincent, en révision pour Journal of Geophysical Research Oceans - Chapitre 4: Importance of particles-based bacterial heterotrophy in a coastal Arctic ecosystem / Marie-Eve Garneau, Warwick F. Vincent, Ramon Terrado, Connie Lovejoy, en révision pour Journal of Marine Systems - Chapitre 5: Conclusion générale.
ASTIS record 74973.
Languages: English
Web: http://archimede.bibl.ulaval.ca/archimede/fichiers/25371/25371.pdf
Libraries: QQLA

The Mackenzie Shelf in the Beaufort Sea, a major ecosystem within the Arctic Basin, receives considerable amounts of terrigenous sediments and organic matter. This region is increasingly impacted by climate warming, which will cause increased riverine inputs of organic carbon due to the northward advance of the treeline, permafrost melting and increased precipitation. The microbial foodweb plays a key rôle in the carbon cycle and energy transfer in ecosystems, but no studies to date have addressed the spatial and temporal variations in bacterial production (BP) and community structure in the Arctic. The objective of this thesis was to evaluate the structure and dynamics of bacterial communities in the coastal arctic shelf environment, with an emphasis on particles and their attached bacteria. A spatial study in the Mackenzie River plume showed that the salinity gradient controls bacterial community structure, which is dominated by Betaproteobacieria in freshwaters, and by Alphaproteobacteria offshore in the Beaufort Sea. Areas strongly affected by the river showed maximal BP, of which 75% to 96% could be attributed to particle-associated (PA) bacteria. This first annual study of BP in the coastal arctic revealed that the Franklin Bay bacterial communities are active all year round, using allochthonous organic carbon inputs to survive during winter darkness. Even though bacteria use labile organic substrates coming from in situ primary production during summer, Franklin Bay seems to be a heterotrophic ecosystem over an annual basis. PA bacteria are especially active in spring and summer, very likely because of seasonal inputs of allochthonous particulate organic matter (POM). DNA analysis by denaturing gradient gel electrophoresis (DGGE) showed that there was phylogenetic differentiation between PA bacterial assemblages and free-living bacterial assemblages at the highest POM concentrations, while at many sites the free-living and attached components were very similar. This thesis underscores the importance of allochthonous particles for microbial foodwebs in coastal arctic habitats, and the need to consider PA bacteria in assessing the biogeochemical response of the coastal Arctic Ocean to climate warming. (Au)

J, H, D, F, E
Archaea; Bacteria; Biological productivity; Biomass; Chlorophyll; Climate change; Estuaries; Estuarine ecology; Fresh-water ecology; Heterotrophic bacteria; Hydrological stations; Marine ecology; Metabolism; Microbial ecology; Particulate organic matter; Phytoplankton; Proteins; River discharges; Salinity; Seasonal variations; Suspended solids; Temporal variations; Theses

G0815, G0812, G01
Franklin Bay, N.W.T.; Mackenzie River, N.W.T.; Polar regions


Importance of particle-associated bacterial heterotrophy in a coastal Arctic ecosystem   /   Garneau, M.-È.   Vincent, W.F.   Terrado, R.   Lovejoy, C.
(Journal of marine systems, v. 75, no. 1-2, Jan. 2009, p. 185-197, ill., map)
References.
ASTIS record 65738.
Languages: English
Web: doi:10.1016/j.jmarsys.2008.09.002
Libraries: ACU

The large quantities of particles delivered by the Mackenzie River to the coastal Beaufort Sea (Arctic Ocean) have implications for the spatial distribution, composition and productivity of its bacterial communities. Our objectives in this study were: (1) to assess the contribution of particle-associated bacteria (fraction >= 3µm) to total bacterial production and their relationships with changing environmental conditions along a surface water transect; (2) to examine how particle-based heterotrophy changes over the annual cycle (Nov 2003-Aug 2004); and (3) to determine whether particle-associated bacterial assemblages differ in composition from the free-living communities (fraction < 3µm). Our transect results showed that particle-associated bacteria contributed a variable percentage of leucine-based (BP-Leu) and thymidine-based (BP-TdR) bacterial production, with values up to 98% at the inshore, low salinity stations. The relative contribution of particle-associated bacteria to total BP-Leu was positively correlated with temperature and particulate organic material (POM) concentration. The annual dataset showed low activities of particle-associated bacteria during late fall and most of the winter, and a period of high particle-associated activity in spring and summer, likely related to the seasonal inputs of riverine POM. Results from catalyzed reporter deposition for fluorescence in situ hybridization (CARD-FISH) confirmed the dominance of Bacteria and presence of Archaea (43-84% and 0.2-5.5% of DAPI counts, respectively), which were evenly distributed throughout the Mackenzie Shelf, and not significantly related to environmental variables. Denaturing gradient gel electrophoresis (DGGE) revealed changes in the bacterial community structure among riverine, estuarine and marine stations, with separation according to temperature and salinity. There was evidence of differences between the particle-associated and free-living bacterial assemblages at the estuarine stations with highest POM content. Particle-associated bacteria are an important functional component of this Arctic ecosystem. Under a warmer climate, they are likely to play an increasing role in coastal biogeochemistry and carbon fluxes as a result of permafrost melting and increased particle transport from the tundra to coastal waters. (Au)

D, F, H, I, E, J
Archaea; Bacteria; Biological productivity; Biological sampling; Carbon cycling; Climate change; Continental shelves; Environmental impacts; Estuarine ecology; Fresh-water ecology; Marine ecology; Melting; Microbial ecology; Microorganisms; Ocean temperature; Particulate organic matter; Permafrost; River discharges; Salinity; Seasonal variations; Sediment transport

G07, G0812
Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.


Surface-based polarimetric C-band scatterometer for field measurements of sea ice   /   Geldsetzer, T.   Mead, J.B.   Yackel, J.J.   Scharien, R.K.   Howell, S.E.L.
(IEEE transactions on geoscience and remote sensing, v. 45, no. 11, Nov. 2007, p.3405-3416, ill.)
Appendices.
References.
ASTIS record 63293.
Languages: English
Web: doi:10.1109/TGRS.2007.907043
Libraries: ACU

A portable surface-based polarimetric C-band scatterometer for field deployment over sea ice is presented. The scatterometer system, its calibration, signal processing, and near-field correction are described. The near-field correction is shown to be effective for both linear polarized and polarimetric backscatter. Field methods for the scatterometer are described. Sample linear polarized and polarimetric backscatter results are presented for snow-covered first-year sea ice (FYI), multiyear hummock ice, and rough melt pond water on FYI. The magnitude of backscatter signature variability due to system effects is presented, providing the necessary basis for quantitative analysis of field data. (Au)

G, F, A
Electronic data processing; Ice rubble fields; Instruments; Logistics; Measurement; Microwave radiation; Puddles; Radar; Sea ice; Snow

G0815, G0814
Franklin Bay, N.W.T.; Hudson Bay; Resolute Passage, Nunavut


Dielectric properties of brine-wetted snow on first-year sea ice   /   Geldsetzer, T.   Langlois, A.   Yackel, J.
(Cold regions science and technology, v. 58, no. 1-2, Aug. 2009, p. 47-56, ill.)
References.
ASTIS record 67394.
Languages: English
Web: doi:10.1016/j.coldregions.2009.03.009
Libraries: ACU

We present measurements, empirical models and a semi-physical dielectric mixture model for the dielectric constant and dielectric loss of brine-wetted snow on first-year sea ice. Experimental data include snow temperatures from -15.9° to 0.0 °C and snow salinities from 0.1 to 12 parts/thousand. We compare dielectric measurements at 50 MHz with brine volume fraction, brine saturation and snow temperature. We present a dielectric mixture model for brine-wetted snow, with depolarization factors and conductivity parameters fitted to experimental data. The dielectric constant of snow increases by a factor of 78.65 times the brine volume fraction. The dielectric loss and conductivity also increase with brine volume fraction. We provide a theoretical treatment of the frequency dispersion of brine-wetted snow between 10 MHz and 40 GHz. The dielectric properties of brine-wetted snow are highly sensitive to changes in brine volume fraction and snow temperature. (Au)

F, G
Capillary action; Crystals; Density; Depth hoar ; Electrical properties; Interstitial water; Mathematical models; Salinity; Sea ice; Size; Snow; Snow metamorphism; Snow stratigraphy; Temperature; Thickness; Water content of snow

G0815, G0814
Allen Bay, Nunavut; Amundsen Gulf, N.W.T.; Hudson Bay


Could the immense aggregation of arctic cod (Boreogadus saida) found in Franklin Bay extend to the Amundsen Gulf?   /   Geoffroy, M.   Fortier, L.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 221
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67169.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

During the CASES program (2003-2004), the continuously operating EK-60 echosounder of the CCGS Amundsen revealed the progressive building up over the winter months of an immense aggregation of Arctic cod in the deeper half of the water column of Franklin Bay (140-235 m). Gill netting and underwater photography confirmed that the aggregation was nearly monospecific. Preliminary visualisation of the hydro-acoustic data recorded by the same instrument during the Circumpolar Flaw Lead System Study (CFL, 2007-2008) shows significant winter aggregations of fish in some distinctive areas of the Amundsen Gulf, mainly south of Banks Island in the 300-400 m depth zone. The comparison of target strength (TS) between the CASES and CFL records should enable us to verify that these new aggregations consist of Arctic cod as well. As in Franklin Bay, the preliminary CFL results suggest that the species tends to aggregate over the continental slope in winter, mostly in lower Pacific Halocline water (140-400 m). Biomass distribution from different locations and depths along the track of the ship will be projected in the temperature-salinity field to test this hypothesis. Understanding Arctic cod migrations and distribution in the Canadian Arctic Ocean is needed to anticipate the response of this key species to climate change and sea ice cover reduction. (Au)

I, D
Animal distribution; Animal migration; Arctic cod; Biomass; Ocean temperature; Salinity; Sonar; Water masses

G0815
Amundsen Gulf, N.W.T.; Franklin Bay, N.W.T.


Interpretation of acoustic data to study arctic cod (Boreogadus saida) winter aggregations in the Amundsen Gulf (southeastern Beaufort Sea)   /   Geoffroy, M.   Fortier, L.
In: International Polar Year Oslo Science Conference, 2010, 8-12 June. - [Oslo : Research Council of Norway, 2010], presentation no. EA11.3-7.4, [1] p.
Abstract of an oral presentation, taken from the USB flash drive distributed at the conference.
ASTIS record 71651.
Languages: English

During the Circumpolar Flaw Lead System Study (CFL, 2007-2008) in the Amundsen Gulf, significant aggregations of fish were detected in winter by the EK-60 echosounder of the CCGS Amundsen. Echo-validation was performed by comparing characteristics of the CFL aggregations to quasi-monospecific aggregations of Arctic cod observed in Franklin Bay during the CASES program (2003-2004). Similar target strengths (TS), the avoidance of temperatures <-1.4°C, the formation of the aggregations in December and their dissipation in May all suggest that, as in CASES, the aggregations observed during CFL were made up of Arctic cod. A multifrequency analysis (38 and 120 kHz) further indicated a mean volume backscattering difference (7MVBS) range between -5dB and 4dB in February and March, consistent with the acoustic signature of Arctic cod. Integrated biomass was calculated over a year and reached a maximum of 0.732 kg/m² in February. Aggregations were only encountered from December to May above the continental slope and migrated from 200 m to 550 m areas through the winter. Arctic cod generally aggregated in the deeper and warmer Atlantic layer, except at maximum observed density in February and immediately before dissipation of the aggregations in late April, when they occupied both the Atlantic Layer and the lower Pacific Halocline. Understanding Arctic cod migrations and distribution in the Canadian Arctic is needed to anticipate the response of this key species to climate change and sea ice cover reduction. Keywords: Arctic cod, aggregations, acoustic, Amundsen Gulf. (Au)

I, D, G, E, J
Animal behaviour; Animal distribution; Animal migration; Arctic cod; Biomass; Climate change; Ice cover; Marine ecology; Ocean temperature; Sea ice; Seasonal variations; Sonar; Water masses

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Migrations and aggregations of arctic cod (Boreogadus saida) during the winter in the Amundsen Gulf (southeastern Beaufort Sea)   /   Geoffroy, M.   Robert, D.   Fortier, L.
In: ArcticNet programme 2010 : annual scientific meeting, 14-17/12/2010, Ottawa, ON = ArcticNet programme 2010 : réunion scientifique annuelle, 14-17/12/2010, Ottawa, ON. - [Québec, Québec] : ArcticNet, 2010, p. 51-52
Abstract of a Topical Session oral presentation.
Indexed a PDF file from the Web.
ASTIS record 73358.
Languages: English
Web: http://www.arcticnetmeetings.ca/asm2010/docs/programme_full_web.pdf
Libraries: ACU

During the Circumpolar Flaw Lead System Study (CFL, 2007-2008) in the Amundsen Gulf, significant aggregations of fish were detected in winter by the EK-60 echosounder of the CCGS Amundsen. Echo-validation was performed by comparing characteristics of the CFL aggregations to monospecific aggregations of arctic cod observed in Franklin Bay during the CASES program (2003-2004). A similar in situ mean target strength (TSN) suggests that, as in CASES, the aggregations observed during CFL were made up of arctic cod. A multifrequency analysis (38 and 120 kHz) further indicated a mean volume backscattering strength difference (Delta MVBS) range between -5dB and 4dB in February and March, consistent with the acoustic signature of arctic cod. Integrated biomass was calculated over ten months and reached a maximum of 0.732 kg/m² in February. Aggregations were only encountered under high sea-ice concentration, from December to April, and aggregating behaviour closely related to the ice cover. We suggest that arctic cod vertical distribution was driven by temperature and prey distribution. The species generally sought for the warm Atlantic Layer during winter, but when forming dense aggregations individuals were also following their zooplanktonic prey in the colder Pacific Halocline. All aggregations were recorded over the continental slope, where it was possible to stay away from the cold upper layers. Diel vertical migration patterns were observed within the aggregations, presumably to avoid visual predators such as ringed seals (Phoca hispida). Arctic cod also migrated from 220 m to 550 m bottom depth areas throughout winter as a response to increasing light intensity. Understanding arctic cod migrations and distribution in the Canadian Arctic is needed to anticipate the response of this key species to climate change and sea-ice cover reduction. (Au)

I, D, G
Animal behaviour; Animal distribution; Animal food; Animal migration; Arctic cod; Biomass; Diurnal variations; Ice cover; Light; Ocean temperature; Predation; Sea ice; Seals (Animals); Seasonal variations; Sonar; Water masses; Zooplankton

G0815
Amundsen Gulf, N.W.T.


Foraminiferal proxies for Late Holocene paleo-sea ice and paleoceanographic conditions in the Amundsen Gulf and Viscount Melville Sound   /   Gibb, O.   Scott, D.   Rochon, A.   Blasco, S.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 222
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67172.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Sea ice extent and its response to warming throughout the Arctic varies spatially, requiring regional, high resolution investigations to determine paleo-sea ice patterns paleoceanographic conditions. Changes in the abundance and composition of foraminiferal assemblages within the Amundsen Gulf and Viscount Melville Sound allow some reconstruction of the dynamics of paleo-sea ice cover within the Western Canadian Arctic Archipelago and Northwest Passage during the late Holocene. The Canadian Arctic Shelf Exchange Study (CASES) and ArcticNet have collected sediment cores and surface samples from 2002 to 2006 in the Beaufort Sea, Amundsen Gulf and the interstitial waters of the Canadian Arctic Archipelago. In the summer of 2004, five boxcores were collected along a transect through the Amundsen Gulf. These cores range from 15 to 35 cm in length, and were collected from depths of 172 to 569 m. Two of the cores are correlated chronostratigraphically with radiocarbon AMS ages. The foraminiferal assemblages demonstrate increased amounts of sea ice from approximately 1000 to 1400 cal years BP, decreasing to seasonally open waters by approximately 300 cal years BP, assuming constant sedimentation rates. One core was collected from the Viscount Melville Sound. It revealed a different foraminiferal assemblage than the cores from the Amundsen Gulf, indicating different water masses were passing through the North West Passage. These paleoceanographic records may also provide insights on the spatial and temporal variability of the Cape Bathurst Polynya, and how this region will respond to continued changes in climate. (Au)

I, B, G, D
Animal distribution; Bottom sediments; Cores; Foraminifera; Ice cover; Oceanography; Radiocarbon dating; Recent epoch; Sea ice; Sedimentation; Spatial distribution; Temporal variations; Water masses

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Arctic Islands waters; Canadian Beaufort Sea; Viscount Melville Sound, N.W.T./Nunavut


Sea ice and paleoceanographic conditions in the Amundsen Gulf, Canadian Arctic during the late Holocene   /   Gibb, O.T.   Scott, D.B.   Schell, T.M.   Rochon, A.   Blasco, S.
In: 2008 Joint Annual Meeting of the Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM : celebrating the International Year of the Planet. - [S.l. : Geological Society of America], 2008, [1] p.
Abstract of an oral presentation (314-11).
Meeting held 5-9 Oct. 2008 in Houston, Texas.
Indexed an HTML page available online.
ASTIS record 75600.
Languages: English
Web: http://a-c-s.confex.com/crops/2008am/webprogram/Paper47605.html

Canada's Arctic region is projected to undergo significant changes in response to future climate change, particularly in regards to sea ice cover. However, despite their potential relevance for understanding future changes, the spatial and temporal dynamics of paleoclimatic and sea ice proxies are poorly known in many Arctic locations. Examinations of long term changes in the abundance and composition of foraminiferal assemblages within the Amundsen Gulf allows some reconstruction of the dynamics of paleo-sea ice cover since the last glaciation. The Canadian Arctic Shelf Exchange Study (CASES) and ArcticNet have collected sediment cores and surface samples from 2002 to 2006 in the Beaufort Sea, Amundsen Gulf and the interstitial waters of the Canadian Arctic Archipelago. In the summer of 2004, a transect of five boxcores through the Amundsen Gulf, ranging from 15 to 35 cm in length, were collected from depths of 172 to 569 m. The five cores correlate chronostratigraphically with radiocarbon AMS ages, and are compared to two previously analysed cores from the Gulf, one of which was located at the front of the former ice margin. Spatial distributions of foraminiferal assemblages were assessed from surface sediments collected across the Beaufort Shelf and Amundsen Gulf. Assemblage differences were characteristic of different oceanic environments. These correlations were used to infer paleoenvironmental conditions, including sea ice cover and freshwater influx throughout the Holocene. Paleoclimatic reconstructions using foraminiferal abundances and assemblages from the Amundsen Gulf transect provide insights on spatial and temporal variations in oceanographic and sea ice conditions within an area of the Canadian Arctic that has not been previously investigated. These results may suggest how this region will respond to continued changes in climate. (Au)

B, D, I, G, J, E
Animal distribution; Animal ecology; Animal population; Bottom sediments; Climate change; Cores; Environmental impacts; Foraminifera; Ice cover; Palaeoclimatology; Palaeoecology; Palaeohydrology; Radiocarbon dating; Recent epoch; Salinity; Sea ice; Spatial distribution; Temporal variations; Water masses; Wildlife habitat

G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Foraminiferal indicators of paleoceanographic and sea-ice conditions in the Amundsen Gulf and Viscount Melville Sound, Canadian Arctic   /   Gibb, O.T.   Scott, D. [Supervisor]
Halifax, N.S. : Dalhousie University, 2009.
xiii, 132 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR63567)
ISBN 978-0-494-63567-4
Thesis (M.Sc.) - Dalhousie University, Halifax, N.S., 2009.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
Appendices.
References.
ASTIS record 74811.
Languages: English
Libraries: NSHD OONL

Sediment cores were collected from the Canadian Arctic Archipelago to reconstruct the region's oceanographic and sea ice history via foraminiferal proxies. Foraminiferal species assemblages reflect changes in sea ice cover due to the dissolution of calcareous foraminifera during increased productivity in ice-free waters. The upper five cm of sediment of the core located in the Amundsen Gulf is characterized by a predominantly agglutinated foraminiferal assemblage that spanned the last century, indicative of a seasonally ice-free Amundsen Gulf. In contrast to the recent assemblage, a predominantly calcareous assemblage indicated carbonate preservation within the Amundsen Gulf during a period of perennial ice extending back to the 9 century AD. During the Medieval Warm Period and the Anthropocene, two recent periods of warmer climate, foraminiferal proxies indicated different sea ice regimes. These results suggest that the factors forcing sea ice extent have changed in recent decades. (Au)

I, B, G, D, J, E, H
Animal distribution; Animal population; Animal taxonomy; Benthos; Biological productivity; Bottom sediments; Carbon; Chemical oceanography; Climate change; Cores; Diatoms; Dinoflagellata; Foraminifera; Ice cover; Ice leads; Isotopes; Marine ecology; Mass spectrometry; Mathematical models; Ocean temperature; Oceanography; Oxygen; Plankton; Polynyas; Primary production (Biology); Radiocarbon dating; Recent epoch; Salinity; Satellite photography; Sea ice; Sea ice ecology; Sedimentation; Spatial distribution; Temporal variations; Theses; Water masses

G0815, G07, G09
Amundsen Gulf, N.W.T.; Baffin Bay-Davis Strait; Canadian Arctic Islands waters; Canadian Beaufort Sea; Lancaster Sound, Nunavut; M'Clure Strait, N.W.T.; Viscount Melville Sound, N.W.T./Nunavut


Foraminiferal and isotopic evidence for sea-ice extent and paleoceanography of the Amundsen Gulf, Canadian Arctic   /   Gibb, O.T.   Scott, D.B.   Rochon, A.   Blasco, S.
(2009 AGU Joint Assembly : the meeting of the Americas, 24-27 May 2009, Toronto, Ontario, Canada. Eos (Washington, D.C.), v. 90, no. 22, Jt. Assem. suppl., 2009, abstract PP71A-05)
Abstract of a poster presentation.
Abstracts can be found online through the AGU Meeting Abstract Database: www.agu.org/meetings/abstract_db.shtml.
ASTIS record 75658.
Languages: English
Libraries: ACU

Paleoclimatic reconstructions based on the identities and isotopic signatures of marine microfossils assist in estimating natural variability of ocean-climate dynamics. Sea-ice extent and its response to warming affects those dynamics, yet remains poorly known in many Arctic regions, including the Western Canadian Arctic Archipelago. Reconstructions of Late Holocene sea ice cover were created from foraminiferal and stable isotopic proxies from sediment cores collected by the Canadian Arctic Shelf Exchange Study (CASES) and ArcticNet. The five boxcores examined were collected in 2004 along a transect through the Central Amundsen Gulf. The top 30 cm of sediment represents an average of 1200 years cal BP, assuming constant sedimentation rates. The benthic calcareous and agglutinated foraminiferal assemblages suggest a decline in perennial sea-ice cover over the last millennium, and that the Amundsen Gulf may have experienced seasonally open waters within the last 300 years cal BP. The oxygen and carbon stable isotopes of benthic and planktonic species both demonstrate the spatial and temporal extent of variations in sea-ice cover and suggest changes in benthic conditions. In addition to facilitating stratigraphic correlation among boxcores through the Amundsen Gulf, the stable isotopes of foraminifera will assist in correlating the paleoceanographic conditions with those from other areas of the Arctic. (Au)

B, D, G, E, I, J
Animal distribution; Benthos; Bottom sediments; Carbon; Climate change; Cores; Effects of climate on ice; Environmental impacts; Foraminifera; Geological time; Ice cover; Identification; Isotopes; Oxygen-18; Palaeoclimatology; Palaeohydrology; Palaeontology; Recent epoch; Sea ice; Sedimentation; Spatial distribution; Stratigraphy; Temporal variations; Zooplankton

G0815
Amundsen Gulf, N.W.T.


Foraminiferal evidence for sea-ice extent and paleoceanography of the Amundsen Gulf, Canadian Arctic   /   Gibb, O.T.   Scott, D.B.   Rochon, A.   Blasco, S.
In: Congrès annuel du GEOTOP, 24 au 26 janvier 2010 = GEOTOP Annual Meeting, January 24th-26th. - Montréal : GEOTOP, 2010, p. 29
Abstract of a poster presentation.
Congress held in Montreal.
Indexed a PDF file available online.
ASTIS record 75626.
Languages: English
Web: http://www.geotop.ca/upload/files/congres_etudiants/Recueil_des_resumes_Janvier_2010.pdf

Sediment cores have recently been collected by the Canadian Arctic Shelf Exchange Study (CASES) and ArcticNet from within the Amundsen Gulf, to determine the region's oceanographic and sea ice history via foraminiferal proxies. One core was dated with 210Pb and 14C radiometric techniques, indicating that the top 5 cm of sediment represents ~100 years, and 815 cal yrs AD is the age of sediments at 31 cm depth. A dendrogram was produced by a Q-mode cluster analysis of 60 foraminiferal species and 85 boxcore samples identifying four distinct clusters: the inner and outer Amundsen Gulf samples within the upper and lower sections of each core. The boundary has been interpreted as a change in sea ice regime. The cores contain recent sediments with a predominantly agglutinated foraminiferal assemblage indicative of a seasonally ice-free Amundsen Gulf over the last century. In contrast to the recent assemblage, a predominantly calcareous assemblage indicated carbonate preservation within the Amundsen Gulf during perennial ice cover during the 9th century AD. The Medieval Warm Period and the Anthropocene, two recent periods of warmer climate, observed different sea ice regimes suggesting that the factors forcing sea ice extent have changed in recent decades. (Au)

B, D, G, E, I, J
Animal distribution; Bottom sediments; Carbonates; Climate change; Cores; Effects of climate on ice; Environmental impacts; Foraminifera; Geological time; Ice cover; Lead; Palaeoclimatology; Palaeohydrology; Radiocarbon dating; Radionuclides; Recent epoch; Salinity; Sea ice; Seasonal variations; Spatial distribution; Stratigraphy; Temporal variations

G0815
Amundsen Gulf, N.W.T.


Measurements of the dissolved inorganic carbon system and associated biogeochemical parameters in the Canadian Arctic, 1974-2009   /   Giesbrecht, K.E.   Miller, L.A.   Davelaar, M.   Zimmermann, S.   Carmack, E.   Johnson, W.K.   Macdonald, R.W.   McLaughlin, F.   Mucci, A.   Williams, W.J.   Wong, C.S.   Yamamoto-Kawai, M.
(Special issue : polar science with polar data. Earth system science data, v. 6, 2014, p. 91-104, ill., maps)
References.
Available through Open Access.
Appendix.
The data set is available for download on the CDIAC (Carbon Dioxide Information Analysis Center) website: http://cdiac.ornl.gov/ftp/oceans/IOS_Arctic_Database/ (doi:10.3334/CDIAC/OTG.IOS_ARCT_CARBN).
ASTIS record 79703.
Languages: English
Web: http://www.earth-syst-sci-data.net/6/91/2014/essd-6-91-2014.html
Web: doi:10.5194/essd-6-91-2014
Libraries: ACU

We have assembled and conducted primary quality control on previously publicly unavailable water column measurements of the dissolved inorganic carbon system and associated biogeochemical parameters (oxygen, nutrients, etc.) made on 26 cruises in the subarctic and Arctic regions dating back to 1974. The measurements are primarily from the western side of the Canadian Arctic, but also include data that cover an area ranging from the North Pacific to the Gulf of St. Lawrence. The data were subjected to primary quality control (QC) to identify outliers and obvious errors. This data set incorporates over four thousand individual measurements of total inorganic carbon (TIC), alkalinity, and pH from the Canadian Arctic over a period of more than 30 years and provides an opportunity to increase our understanding of temporal changes in the inorganic carbon system in northern waters and the Arctic Ocean. (Au)

D, E, J
Arctic Environmental Strategy; Beaufort Sea Project (Canada); Canada. Natural Resources Canada; Canada. Northern Oil and Gas Action Program; Canadian Arctic Shelf Exchange Study; Carbon; Carbon cycling; Chemical oceanography; Climate change; Databases; Dissolved organic carbon; Effects monitoring; Marine ecology; Mathematical models; Measurement; Nitrogen; Nitrogen cycling; Ocean-atmosphere interaction; Particulate organic matter; Phosphorus; Quality assurance; Research; Research funding; Silicates; Temporal variations; Water pH

G061, G04, G07, G03, G0815, G09, G0814
Alaska, Gulf of; Baffin Bay-Davis Strait; Beaufort Sea; Bering Strait; Canada Basin, Arctic Ocean; Canadian Arctic Islands waters; Chukchi Sea; Hudson Bay; Labrador Sea; North Pacific Ocean; St. Lawrence, Gulf of, Canada


The supply and preservation of ancient and modern components of organic carbon in the Canadian Beaufort Shelf of the Arctic Ocean   /   Goñi, M.A.   Yunker, M.B.   Macdonald, R.W.   Eglinton, T.I.
(Marine chemistry, v. 93, no. 1, Jan. 2005, p. 53-73, ill., map)
(NOGAP project no. B.06 : Beaufort Sea oceanography)
References.
Samples were originally collected under the NOGAP B.6 project.
ASTIS record 62005.
Languages: English
Web: doi:10.1016/j.marchem.2004.08.001
Libraries: ACU

The provenance of organic matter in sediments from the Mackenzie River and Beaufort Shelf was investigated using the stable carbon and radiocarbon isotopic compositions of bulk organic matter and the stable carbon isotopic compositions of individual organic compounds, including lignin-derived phenols and lipid-derived fatty acids. Most river suspended sediments and shelf surface sediments contained organic carbon characterized by highly depleted Delta 14C values that were consistent with average radiocarbon ages exceeding 7000 years. The stable carbon isotopic signatures of lignin phenols were uniformly depleted (-25 >= delta 13C >= -32‰), indicating the predominant contributions of C3 vascular plant sources. The isotopic compositions of C14 and C16 fatty acids exhibited important contrasts between the river (-36‰ to -40‰) and shelf (-25‰ to -29‰) sediments that were consistent with contributions from freshwater algae and/or vascular plants in the former and marine phytoplankton in the latter. Using 14C isotopic mass balance, the abundances of modern and ancient organic matter were quantitatively constrained. The fate of organic matter in the Beaufort Shelf was explored by normalizing these abundances to the specific surface area of sediments. Ancient organic carbon, which may include old pre-aged soil material as well as fossil bitumen or kerogen, accounted for the majority (~70%) of the particulate organic matter exported by the Mackenzie River and deposited in surface sediments of the Beaufort Shelf. Modern organic carbon accounted for ~30% in both river and shelf sediments, with significant contributions from vascular plant-derived materials in both river and shelf samples and from marine algae in the shelf sediments. Respiration (and/or leaching) of particle-bound marine organic matter dominates the carbon metabolism in the Mackenzie Delta/Beaufort Shelf region. However, land-derived pools, including modern carbon derived from vascular plants as well as ancient carbon also appeared to undergo a degree of post-depositional degradation prior to burial in the shelf. These novel source apportionments are reflected in an updated carbon budget for the study area. (Au)

B, F, D, H
Algae; Bottom sediments; Carbon; Carbon cycling; Chromatography; Fatty acids; Isotopes; Lipids; Mass balance; Mass spectrometry; Measurement; Metabolism; Nitrogen; PAHs; Particulate organic matter; Peat; Phytoplankton; Plant physiology; Plant respiration; Plants (Biology); Radiocarbon dating; Suspended solids; Watersheds

G07, G0812, G0811
Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Kugmallit Bay, N.W.T.; Mackenzie Bay region, N.W.T./Yukon; Middle Channel (Mackenzie River), N.W.T.; Reindeer Channel, N.W.T.


Measurements of blowing snow, part II : mass and number density profiles and saltation height at Franklin Bay, NWT, Canada   /   Gordon, M.   Savelyev, S.   Taylor, P.A.
(Cold regions science and technology, v. 55, no. 1, Jan. 2009, p. 75-85, ill.)
Appendix.
References.
ASTIS record 65386.
Languages: English
Web: doi:10.1016/j.coldregions.2008.07.001
Libraries: ACU

Blowing snow is a frequent and significant winter weather event, and there is currently a need for more observations and measurements of blowing snow, especially in arctic and subarctic environments. This paper is the second part in a two part series studying blowing snow in Churchill, Manitoba, and Franklin Bay, NWT. In this part, the development and use of a camera system to measure the relative blowing snow density profile near the snow surface is described. This system has been used, along with standard meteorological instruments and optical particle counters, during a field campaign at Franklin Bay, NWT. A best-fit to the mass density profile in the saltation layer is derived, assuming a half-normal distribution of the vertical ejection velocity of saltating particles. Within the saltation layer, the observed vertical profile of mass density is found to be proportional to the function exp(-0.61z/h), where h is the average height of the saltating particles. For the range of conditions studied, h varies from 1.0 to 10.4 mm, while the extent of the saltation layer varies from 17 to over 85 mm. There is a weak correlation between h and the square of friction velocity. There are weak negative correlations between h and temperature and relative humidity. No correlation is seen between h and the snow age. At greater heights, z>0.2 m, the blowing snow density varies according to a power law (rho(s) is proportional to z**-gamma), with a negative exponent 0.5
F, E
Atmospheric humidity; Atmospheric temperature; Blowing snow; Boundary layers; Density; Friction; Instruments; Mathematical models; Photography; Saltation; Size; Snowdrifts; Spatial distribution; Stress; Velocity; Viscosity; Weather stations; Winds

G0815
Franklin Bay, N.W.T.


The electric field during blowing snow events   /   Gordon, M.   Taylor, P.A.
(Boundary-layer meteorology, v.130, no. 1, Jan. 2009, p. 97-115, ill.)
References.
ASTIS record 65878.
Languages: English
Web: doi:10.1007/s10546-008-9333-7
Libraries: ACU

A model is proposed to determine the electric field strength in blowing snow. To test this model, the electric field strength was measured over an 80-day period during the Canadian Arctic Shelf Exchange Study (CASES) in 2004. The electric field strength at 0.5 m correlates well with the difference between 10-m wind speed and a threshold wind speed, although there is a large amount of variation between the electric fields generated during different blowing snow events. Although the model predicts that the electric field should be proportional to particle number density, the correlation is weak. The correlation of wind speed and electric field strength suggests that particles become charged primarily due to friction-induced temperature difference as they impact upon the surface. The strength of the electric field is likely influenced by a large number of other factors that are difficult to measure. However, the model predicts electric field strengths in excess of 25 kV/m near the surface, which would have a significant effect on particle motion. (Au)

F, E
Atmospheric humidity; Atmospheric temperature; Blowing snow; Boundary layers; Crystals; Density; Electrical properties; Fracturing; Friction; Instruments; Mathematical models; Salinity; Saltation; Size; Snow; Snowdrifts; Spatial distribution; Strength; Sublimation; Surface temperature; Temperature; Velocity; Weather stations; Winds

G0815
Franklin Bay, N.W.T.


Introduction [Response of marine ecosystems to global change : ecological impact of appendicularians]   /   Gorsky, G.   Youngbluth, M.J.   Deibel, D.
In: Response of marine ecosystems to global change : ecological impact of appendicularians / Edited by G. Gorsky, M.J. Youngbluth, and D. Deibel. - Paris : Éditions Scientifique GB, 2005, p. 3-6, ill.
References.
ASTIS record 74711.
Languages: English
Libraries: QMM

THe NATO Advanced Research Workshop entitled "RESPONSE OF MARINE ECOSYSTEMS TO GLOBAL CHANGE: ECOLOGICAL IMPACT OF APPENDICULARIANS" was convened to consider new insights into the phylogeny, diversity, population dynamics, nutritional biology and role in carbon flux of appendicularians. ... It was held in Villefranche-sur-mer from December 16 to 20, 2001. ... Sixty scientists from 18 countries attended the workshop .... Thirty-one oral contributions were presented and methods of sampling, culture, and experimentation as well as the roles of appendicularians as a biological and ecological model organism were discussed during the workshop. Interest in appendicularians is increasing due to significant progress made in our understanding of their place in evolutionary biology, genomics, ecophysiology and biogeochemistry. In chordate evolution, the phlyogenetic position of Appendicularia is still controversial .... Appendicularians are evolutionarily primitive relatives of vertebrates .... Appendicularians display the lowest genome sizes among metazoans. ... The diversity of this group is much larger than appreciated previously. ... The peculiar feeding behaviours of appendicularians enhances their capability of adaptation to extreme environments such as the oligotrophic or deep seas. Appendicularians are efficient intermediaries between the pico- and nanoseston and higher consumers .... They exhibit a rapid gut passage time and relatively high assimilation efficiency. ... The structural simplification of the gut allows for high food processing efficiency that is needed during the short life cycle. New data were reported on the biochemistry of appendicularians .... Biochemical composition, appropriate size range, slow swimming speed and the relatively high abundance in the upper water layer indicate that appendicularians are suitable food for planktotrophic predators, and especially valuable as firstfeed for fish larvae .... The role of appendicularians in the vertical export of particulate matter is related to their ecophysiology and nutritional biology. Their cosmopolitan distribution in the world ocean and in the water column (in photic and aphotic depths) and high clearance, ingestion and fecal production rates of open ocean and coastal populations ... indicate that appendicularians are important contributors to the biogenic carbon cycle. Furthermore, as most of the particulate organic carbon exported from the ocean surface to the sea floor sinks as large, relatively rare particles with rapid settling rates, discarded appendicularian houses, including particles remaining in the house filters, are potentially a major source of this sinking carbon because of their large size, high abundances and rapid production rates .... Appendicularian contribution to secondary production is positively related to the primary production, but temperature is the most significant factor governing individual growth rate .... The population dynamics of appendicularians are primarily under biometeorological control .... The close relationship between assemblages of appendicularian species and physical environmental factors suggests their potential as indicator species of climate changes and of water masses. The collection of international contributions presented in this book reflects the significant progress made in our understanding in regard to the biology and ecology of appendicularians. In order to correctly evaluate the response of appendicularians to environment perturbation and the magnitude of their ecological impact, scientific activity must strengthen and develop in all the above-mentioned fields. We believe that this workshop and the resulting links between participants and institutions will have forged new partnerships that will foster increased, long-term international collaboration. (Au)

I, J, D, H
Adaptation (Biology); Amino acids; Animal anatomy; Animal behaviour; Animal distribution; Animal ecology; Animal food; Animal growth; Animal physiology; Animal population; Animal reproduction; Animal waste products; Appendicularians; Biological productivity; Biological sampling; Biomass; Carbon cycling; Enzymes; Evolution (Biology); Genetics; Intestines; Lipids; Marine biology; Ocean temperature; Predation; Primary production (Biology); Proteins; Seasonal variations; Sedimentation; Suspended solids; Tunicates; Vertebrates

G02, G15, G09, G04, G05, G11
Antarctic waters; Arctic waters; Bering Sea; North Water Polynya, Baffin Bay; Northeast Water Polynya, Greenland Sea


Light, nutrients and primary production   /   Gosselin, M.   Brugel, S.   Demers, S.   Juul-Pedersen, T.   Larouche, P.   LeBlanc, B.   Michel, C.   Nozais, C.   Poulin, M.   Price, N.   Riedel, A.   Rózanska, M.   Simpson, K.   Tremblay, J.-É.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 4, p. 69-83, ill.
References.
ASTIS record 67478.
Languages: English
Libraries: ACU

... During this investigation, light spectral intensity, nutrient availability, nutrient uptake, size-fractionated microalgal production and biomass, microbial distribution, taxonomic composition of protists, and vertical fluxes of biogenic carbon were assessed in ice-covered and ice-free waters of the three oceanographic provinces of the eastern Beaufort Sea. Continuous measurements from September 2003 to August 2004 allowed us to monitor nutrient/microalgal dynamics and sinking exports throughout the annual physical and chemical forcing cycles characteristic to this region (and other Arctic shelves). Until now, the concentration of nutrients available to microalgae at the end of winter in the Beaufort Sea was a matter of speculation. We have shown that during fall 2003 and winter 2004 the renewal of nutrients in the upper euphotic zone was small due to modest mixing by wind, convection, and brine rejection. We hypothesize that other mechanisms of N and P supply may also play determining roles in this context. Approximately, one third of the NO3 reservoir available to phytoplankton in spring 2004 was likely supplied by nitrification above the resilient halocline. However, this remains to be confirmed experimentally. Irradiance clearly affects the timing and the rate of primary production in seasonally ice-covered Arctic waters, however our analysis supports the notion that cumulative new and net production are driven primarily by nitrogen loading. The response of phytoplankton to declining ice cover may depend more on the alteration of nutrient loads by atmospheric forcing and freshwater input than on changes in light availability. DOP [dissolved organic phosphorus] concentrations were greatly enriched in Pacific derived waters and represent an important phosphorus input to the Arctic that has previously been overlooked. The deep water of the Amundsen Gulf/Cape Bathurst polynya exhibited a marked divergence in nutrient and oxygen content compared to waters of similar depth in the Beaufort Sea. Our analysis suggests that the residence time of these waters in the Amundsen Gulf is sufficiently long to allow the accumulation of nutrients from the remineralization of exported diatom material. The enrichment confirms the importance of the polynya as a pump for transferring nutrients (and ultimately carbon) to depth. The Cape Bathurst polynya appears to be remarkably similar to other polynyas in the Arctic and Antarctic oceans in that the spring new production represents 40% of the annual new production and occurs over a relatively short period of time following ice retreat. The variable acclimation strategies among microalgal species could be one of the driving forces for creating a diverse flora and enabling the Arctic Ocean to be a productive area. Newly formed sea ice is significantly enriched with large photosynthetic cells (>5µm) in the fall. Microorganisms in newly formed sea ice are active, taking up NO3 and Si(OH)4 and producing NH4. This study has shown that EPS [exopolymeric substances] not only contributes directly to the carbon pool in first-year sea ice, but also influences carbon cycling within the sea ice and the fate of sea ice carbon once released to the water column. Photoprocesses are primarily responsible for elevated carbon monoxide levels in sea ice, and photoremineralization in sea ice may influence the organic carbon cycle of the Arctic Ocean. The Mackenzie River plume has a strong influence on the sinking export of particulate material on the Beaufort Sea shelf and slope. Regardless of the spatial and interannual variability between sampling stations, a strong seasonal signature in the species composition of the sinking protist assemblages emerged for the study area. ... The impacts of climate change on carbon cycling in Arctic marine communities are difficult to predict. However, this study suggests that factors changing the patterns of ice algal production on Arctic shelves may have significant consequences for carbon processing and storage in benthic sediments. ... (Au)

H, J, D, E, G, F, I, A, B
Algae; Animal respiration; Bacteria; Benthos; Biomass; Bottom sediments; Carbohydrates; Carbon; Carbon cycling; Carbon monoxide; Chlorophyll; Copepoda; Diatoms; Dinoflagellata; Food chain; Formation; Isotopes; Light; Marine ecology; Microbial ecology; Microorganisms; Nitrogen; Nitrogen cycling; Ocean currents; Ocean temperature; Optical properties; Oxygen; Phosphorus; Photosynthesis; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Polynyas; Primary production (Biology); Radionuclides; Remote sensing; River discharges; Salinity; Sea ice; Sea ice ecology; Seasonal variations; Sedimentation; Silica; Size ; Spatial distribution; Sugars; Suspended solids; Temporal variations; Water masses; Winds

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Structure and dynamics of the Amundsen Gulf eddies   /   Gratton, Y.   Prieur, L.   Tremblay, J.-É.   Mucci, A.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 85
Abstract of a Topical Session presentation.
Indexed a PDF file from the Web.
ASTIS record 66885.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

The source of freshwater, nutrients, dissolved and particulate material found in the Amundsen Gulf can be both local and remote. One coherent feature that can transport freshwater, mass and even complete ecosystems over large distances is the eddy. Canada Basin eddies have been recently observed to last for months. They can be generated in late fall or winter as far as the shelf break in the Chukchi Sea or formed locally at freezing time and / or melting time. One eddy was observed in Franklin Bay in December 2003 during CASES (Canadian Arctic Shelf Exchanges Study) and two more were observed in the Amundsen Gulf in January and March of 2008 during CFL (Circumpolar Flaw Lead Study). The 2003 eddy was probably generated locally while the 2008 eddies may have drifted in from the Canada Basin. In this paper, we discuss the biological, chemical and physical properties of the observed Amundsen Gulf eddies and speculate on their possible generating mechanisms. (Au)

D
Chemical oceanography; Formation; Ocean temperature; Oceanography; Physical properties; Sea water; Suspended solids

G0815, G07
Amundsen Gulf, N.W.T.; Canada Basin, Arctic Ocean; Franklin Bay, N.W.T.


Microfossil evidence for recent changes to Hudson Bay oceanography   /   Griffiths, J.   Scott, D. [Supervisor]
Halifax, N.S. : Dalhousie University, 2010.
x, 115 p. : ill., maps ; 28 cm.
Thesis (M.Sc.) - Dalhousie University, Halifax, N.S., 2010.
Indexed a PDF file from DalSpace, Faculty of Graduate Studies online theses.
References.
Appendices.
ASTIS record 76366.
Languages: English
Web: http://hdl.handle.net/10222/13136
Libraries: OONL NSHD

In 2005, box cores were collected throughout the Hudson Bay and Strait. A detailed micropaleontological data set has been generated from these cores for this study and is combined with geochemical and geochronological data (Kuzyk et al., 2009) to observe temporal and spatial oceanic changes throughout the bay and strait. All of the cores show an increase in brackish water species (tintinnids) and agglutinated foraminifera, and coincident decreases in calcareous foraminifera in younger core sections. In general, these microfossil trends are correlated to higher organic matter content in the younger core sections, likely from a more extensive freshwater plume that causes a lowered pH in the superficial sediments and conditions less favourable for the preservation of calcareous tests. Furthermore, with a 14C age constraint on one of the cores, the mid-Holocene depositional and paleoceanographic history is represented, and provides evidence of marine invasion by 7100 cal yrs BP. (Au)

B, I, D, F, J, G
Animal distribution; Animal food; Animal taxonomy; Bottom sediments; Carbonates; Ciliata; Cores; Foraminifera; Geochemistry; Interstitial water; Isotopes; Lead; Ocean currents; Oceanography; Palaeohydrology; Palaeontology; Radionuclides; River discharges; Rivers; Salinity; Sea ice; Soil pH; Suspended solids; Temporal variations; Theses; Uranium; Water masses; Wildlife habitat; Zooplankton

G0814, G0815
Hudson Bay; Hudson Strait region, Nunavut/Québec; Hudson Strait, Nunavut/Québec


Application of airborne and surface-based EM/Laser measurements to ice/water/sediment models at Mackenzie Delta sites   /   Holladay, J.S.
Dartmouth, N.S. : Bedford Institute of Oceanography, 2006.
iv, 47 p. : ill., maps ; 28 cm.
(Canadian technical report of hydrography and ocean sciences, no. 249)
Appendices.
References.
Cover title.
Indexed a PDF file from the Web.
French abstract provided.
ASTIS record 60654.
Languages: English
Web: http://www.mar.dfo-mpo.gc.ca/science/ocean/seaice/Publications/holladay07.pdf
Libraries: ACU

This report presents a new inversion methodology capable of displaying shallow coastal morphology properties by reprocessing Electromagnetic - Laser (EM) data collected by helicopter-borne sensors. The analysis used the EM data collected during the CASES program ([Canadian] Arctic Shelf Exchange Study) and showed that zones of frozen sediment beneath bottom-fast ice could be easily distinguished from adjacent zones where the sediments were not frozen. It also appeared that such zones had a spatial signature that distinguished them from areas where substantial thicknesses of fresh water were present beneath the ice. Processing of EM data using the new methodology can easily be carried out in the field on a laptop computer. (Au)

F, G, B, D, A
Aerial surveys; Bathymetry; Bottom sediments; Canadian Arctic Shelf Exchange Study; Detection; Electrical properties; Electromagnetic induction; Fast ice; Frozen ground; Helicopters; Instruments; Mathematical models; Numeric databases; Oceanography; Pack ice; River ice; Runoff; SAR; Sea ice; Sea water; Snow; Stamukhi; Surface properties; Thickness; Water

G0812, G0815, G07
Beaufort Sea; Franklin Bay, N.W.T.; Hooper Island (69 41 N, 134 53 W) waters, N.W.T.; Kugmallit Bay, N.W.T.; Mackenzie Delta, N.W.T.


Microbiology in polar oceans   /   Hollibaugh, J.T.   Lovejoy, C.   Murray, A.E.
(A sea of microbes. Oceanography (Washington, D.C.), v. 20, no. 2, June 2007, p. 140-145, ill.)
References.
Paper in Section V (Examples of Diversity), Chapter 10 (Microbial Communities), and subdivision B (Polar Microbiology).
Indexed a PDF file available online.
ASTIS record 74706.
Languages: English
Web: http://www.tos.org/oceanography/issues/issue_archive/issue_pdfs/20_2/20.2_hollibaugh_et_al.pdf
Web: doi:10.5670/oceanog.2007.59

... Polar oceans are distinct from other oceanic environments in a number of ways, but the presence of sea ice is a major habitat difference. ... Sea ice serves as a support matrix for a diverse and dynamic assemblage of microbes, including phytoplankton and prokaryotes, often referred to as the sea-ice microbial community, or SIMCO. Growth of ice-associated microalgae can lead to extreme carbon enrichment in the ice, fueling microbial production and providing a food supply for herbivorous metazoa. ... Limited areas of persistently open water provide habitats that contrast with areas that are ice covered during much of the year. These open-water areas, called polynyas, result from a variety of physical processes. There have been several studies focusing on polynyas in recent years, notably the Canadian-led North Water (NOW) Polynya study .... The NOW polynya was occupied for over four months in 1998, from April through July, and also sampled in the late summer and early fall of 1997 and 1999 .... These studies show that microbes in the polynya were more active than their counterparts under the adjacent ice cover. ... SIMCO are rich communities of prokaryotic and eukaryotic organisms found in sea ice at both poles. ... The diversity and ecology of SIMCO bacteria have been the subjects of numerous studies over the years, with recent efforts focusing on describing the phylogenetic composition of bacterial assemblages. Archaeal populations have not been characterized as thoroughly, though they have been detected in SIMCO in at least one study .... Sea-ice-associated bacteria are more likely to be true psychrophiles (optimal growth temperatures <15°C) ... than their planktonic counterparts, and produce more colony-forming units (CFU) per volume sampled than seawater populations .... Most SIMCO bacteria are affiliated with the Proteobacteria (alpha- and gamma-Proteobacteria), Bacteriodetes, and Actinobacteria phyla. ... Bacterioplankton, including organisms in the domains Bacteria and Archaea, dominate the picoplankton in both the Arctic and Southern Oceans. ... Bacterioplankton blooms have been detected in the sub-Antarctic ... and in the Ross Sea during late summer ..., lagging, rather than being directly coupled to, seasonal spring phytoplankton blooms as they are at lower latitudes. In addition to strong seasonal dynamics in bacterioplankton abundance and activity, bacterial species composition in coastal Antarctic Peninsula waters shifts. Phylogenetic analyses based on 16S rRNA genes suggest over 50% turnover in community composition between winter and summer .... Psychrophilic marine bacteria are phenotypically and genotypically divergent in comparison to their mesophilic relatives. Psychrophile genomes may contain specific genes that facilitate cold adaptation, such as the nucleic-acid-binding proteins .... Planktonic archaea in polar waters appear to be dominated by the marine Group I Crenarchaeota .... Group II marine Euryarchaeota have also been detected ..., as have GIII and GIV Crenarchaeota in the deep polar frontal waters of the Antarctic ... and in Arctic waters .... (Au)

H, I, J, G, D
Algae; Archaea; Bacteria; Cold adaptation; Enzymes; Genetics; Marine biology; Microbial ecology; Microorganisms; Ocean temperature; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Polynyas; Proteins; Psychrophilic bacteria; Salinity; Sea ice; Sea ice ecology; Seasonal variations; Wildlife habitat

G02, G15, G09
Antarctic waters; Arctic waters; North Water Polynya, Baffin Bay


A vessel transit assessment of sea ice variability in the western Arctic, 1969-2002 : implications for ship navigation   /   Howell, S.E.L.   Yackel, J.J.
(Canadian journal of remote sensing, v. 30, no. 2, Apr. 2004, p. 205-215, ill., maps)
References.
ASTIS record 63269.
Languages: English
Web: doi:10.5589/m03-062
Libraries: ACU

Recent investigations have shown reduced sea ice extents in Arctic regions and subsequently suggested that the Northwest Passage (NWP) might be able to sustain a prolonged shipping season. To date, no scientific evidence has been presented, within a ship navigation framework, to support increased marine traffic. The Arctic Ice Regime Shipping System (AIRSS) ice numeral (IN), which controls shipping activity in Canadian Arctic waters, was spatially assimilated with the Canadian Ice Service (CIS) historical digital database utilizing a geographic information system (GIS). INs provide a quantifiable framework for examining historical ice states in the context of ship navigation. Results provide a spatial and temporal assessment of ship navigation variability, within a ship transit framework from 1969 to 2002 for the western portion of the NWP. Feasible routes through the NWP experience extreme interannual variability in INs over the past 34 years. Yearly fluctuations of the IN can be attributed to the frequency of multiyear ice (MYI) encounters. The western coast of Banks Island experienced lower INs since 1991 and may be a potential barrier to completely navigating the NWP. Decreases in INs were also found to be associated with the positive signal of the arctic oscillation (AO) index. High-latitude MYI invasions into NWP shipping lanes appear [to] be a major pitfall of future navigation routing in the face of climate warming. (Au)

G, L, E, J, D
Atmospheric circulation; Canadian Ice Service; Climate change; Effects of climate on ice; Geographical positioning systems; Ice control; Ice forecasting; Ice navigation; Marine navigation; Marine transportation; Meteorology; Ocean currents; Ocean temperature; Sea ice; Spatial distribution; Temporal variations; Thermodynamics; Thickness; Water masses; Winds

G07, G0815
Banks Island waters, N.W.T.; Barrow Strait, Nunavut; Canadian Beaufort Sea; M'Clure Strait, N.W.T.; Northwest Passage; Peel Sound, Nunavut; Prince of Wales Strait, N.W.T.; Victoria Strait, Nunavut; Viscount Melville Sound, N.W.T./Nunavut


An evaluation of SeaWinds/QuikSCAT data for the estimation of the decay status of first-year sea ice   /   Howell, S.E.L.   Yackel, J.J.   De Abreu, R.A.   Geldsetzer, T.   Breneman, C.
In: IGARSS 2004 : 2004 IEEE International Geoscience and Remote Sensing Symposium proceedings : science for society : exploring and managing a changing planet, 20-24 September 2004, Anchorage, Alaska. - Piscataway, N.J. : Institute of Electrical and Electronics Engineers, c2004, v. 3, p.2151-2154, ill., maps
References.
Alternate title of proceedings: Science for society : exploring and managing a changing planet.
Alternate title of proceedings: Geoscience and Remote Sensing Symposium, 2004, IGARSS'04, proceedings, 2004 IEEE International.
ASTIS record 64914.
Languages: English
Web: doi:10.1109/IGARSS.2004.1370785
Libraries: ACU

This analysis evaluates the temporal evolution of the microwave backscatter coefficient (sigma°) and VV/HH sigma° co-polarization ratio from Qscat for estimating sea ice thermodynamics. Qscat sigma° were compared against RADARSAT-1 SAR sigma° and in situ data from the Collaborative Interdisciplinary Cryospheric Experiment (C-ICE) for 2000, 2001, and 2002 were used as validation. Results indicate that the temporal evolution of sigma° from Qscat is analogous to RADARSAT-1. The Qscat sigma° temporal evolution has the ability to identify Winter, Snow Melt, and Ponding thermodynamic states. Moreover, the co-polarization VV/HH ratio of Qscat provides a more robust estimate of the Ponding state and identifies the Drainage state that is difficult to detect by single polarization SAR. (Au)

G, F, E, A, L
Breakup; Collaborative Interdisciplinary Cryospheric Experiment; Drainage; Ice cover; Ice forecasting; Marine transportation; Melting; Microwave radiation; Navigational aids; Pack ice; Radar; Remote sensing; SAR; Satellites; Sea ice; Seasonal variations; Snowmelt; Surface properties; Temporal variations; Thermodynamics; Water content of snow; Winds

G0815
Cornwallis Island waters, Nunavut; Parry Channel, N.W.T./Nunavut; Queen Elizabeth Islands waters, N.W.T./Nunavut


On the utility of SeaWinds/QuikSCAT data for the estimation of the thermodynamic state of first-year sea ice   /   Howell, S.E.L.   Yackel, J.J.   De Abreu, R.   Geldsetzer, T.   Breneman, C.
(IEEE transactions on geoscience and remote sensing, v. 43, no. 6, June 2005, p.1338-1350, ill., maps)
References.
ASTIS record 63277.
Languages: English
Web: doi:10.1109/TGRS.2005.846153
Libraries: ACU

The thermodynamic state of sea ice is important to accurately and remotely monitor in order to provide improved geophysical variable parameterizations in sea ice thermodynamic models. Operationally, monitoring the thermodynamic state of sea ice can facilitate eased ship navigation routing. Sea-Winds/QuikSCAT (QuikSCAT) dual-polarization [i.e., horizontal (HH) and vertical (VV)] active microwave data are available at a sufficiently large spatial scale and high temporal resolution to provide estimates of sea ice thermodynamics. This analysis evaluated the temporal evolution of the backscatter coefficient (sigma°) and VV/HH copolarization ratio from QuikSCAT for estimating sea ice thermodynamics. QuikSCAT estimates were compared against RADARSAT-1 synthetic aperture radar (SAR) imagery and the Canadian Ice Service (CIS) prototype operational ice strength algorithm. In situ data from the Collaborative Interdisciplinary Cryospheric Experiment (C-ICE) for 2000, 2001, and 2002 were used as validation. Results indicate that the temporal evolution of sigma° from QuikSCAT is analogous to RADARSAT-1. The QuikSCAT sigma° temporal evolution has the ability to identify winter, snow melt, and ponding thermodynamic states. Moreover, the copolarization VV/HH ratio of QuikSCAT could provide a second estimate of the ponding state in addition to identifying the drainage state that is difficult to detect by single-polarization SAR. QuikSCAT detected thermodynamic states that were found to be in reasonable agreement to that of in situ observations at the C-ICE camp for all years. Operational implications of this analysis suggest QuikSCAT is a more effective and efficient medium for monitoring ice decay compared to RADARSAT-1 and can be utilized to provide more robust modeled ice strength thresholds. (Au)

G, A, E, L, F, J
Albedo; Atmospheric temperature; Breakup; Canadian Arctic Shelf Exchange Study; Canadian Ice Service; Climate change; Collaborative Interdisciplinary Cryospheric Experiment; Ice cover; Ice forecasting; Ice navigation; Mathematical models; Melting; Meteorology; Microwave radiation; Numeric databases; Puddles; Radar; Radiation budgets; Remote sensing; SAR; Satellites; Sea ice; Seasonal variations; Snowmelt; Solar radiation; Spatial distribution; Strength; Surface properties; Temporal variations; Thermodynamics; Thickness

G0815, G0813
Admiralty Inlet, Nunavut; Barrow Strait, Nunavut; Canadian Arctic Islands; Canadian Arctic Islands waters; Creswell Bay, Nunavut; Griffith Island waters, Nunavut; Lancaster Sound, Nunavut; Lowther Island waters, Nunavut; Northwest Passage; Parry Channel, N.W.T./Nunavut; Peel Sound, Nunavut; Prince Leopold Island waters, Nunavut; Prince Regent Inlet, Nunavut; Wellington Channel, Nunavut


Application of a SeaWinds/QuikSCAT sea ice melt algorithm for assessing melt dynamics in the Canadian Arctic Archipelago   /   Howell, S.E.L.   Tivy, A.   Yackel, J.J.   Scharien, R.K.
(Journal of geophysical research, v.111, no. 7, C07025, July 2006, 21 p., ill., maps)
References.
ASTIS record 63261.
Languages: English
Web: doi:10.1029/2005JC003193
Libraries: ACU

A remotely sensed sea ice melt algorithm utilizing SeaWinds/QuikSCAT (QuikSCAT) data is developed and applied to sea ice [in] the Canadian Arctic Archipelago (CAA) from 2000 to 2004. The extended advanced very high resolution radiometer Polar Pathfinder (APP-x) data set is used to identify spatially coupled relationships between sea ice melt and radiative forcings. In situ data from the Collaborative Interdisciplinary Cryospheric Experiment (C-ICE) (2000, 2001, and 2002) and the Canadian Arctic Shelf Exchange Study (CASES) (2004) are used to validate APP-x data during the melt period. QuikSCAT-detected maps of melt onset, pond onset, and drainage are created from 2000 to 2004, and results indicate considerable interannual variability of melt dynamics within the CAA. In some years, melt stages are positively spatially autocorrelated, whereas other years exhibit a negative or no spatial autocorrelation. QuikSCAT-detected stages of melt are found to be influenced by interannual varying amounts and timing of radiative forcing making prediction difficult. The spatiotemporal variability of ice melt also influences the distribution of ice within the CAA. The lower-latitude regions of the CAA are shown to have accumulated increasing concentrations of multiyear ice from 2000 to 2005. This paper concludes with a discussion of the interplay between thermodynamic and dynamic sea ice processes likely to have contributed to this trend. (Au)

G, D, E, J
Albedo; Atmospheric temperature; Breakup; Canadian Arctic Shelf Exchange Study; Climate change; Collaborative Interdisciplinary Cryospheric Experiment; Effects of climate on ice; Formation; Ice cover; Ice forecasting; Maps; Mathematical models; Measurement; Melting; Microwave radiation; Movement; Numeric databases; Ocean-atmosphere interaction; Radar; Radiation budgets; Remote sensing; Satellites; Sea ice; Seasonal variations; Solar radiation; Spatial distribution; Surface properties; Temporal variations; Thermodynamics; Water content of snow; Winds

G0815, G0813
Canadian Arctic Islands; Canadian Arctic Islands waters; Northwest Passage; Parry Channel, N.W.T./Nunavut


Visibility during blowing snow events over Arctic sea ice   /   Huang, Q.   Hanesiak, J.   Savelyev, S.   Papakyriakou, T.   Taylor, P.A.
(Weather and forecasting, v. 23, no. 4, Aug. 2008, p. 741-751, ill., maps)
References.
ASTIS record 74330.
Languages: English
Web: doi:10.1175/2008WAF2007015.1
Libraries: ACU

A field study on visibility during Arctic blowing snow events over sea ice in Franklin Bay, Northwest Territories, Canada, was carried out from mid-January to early April 2004 during the Canadian Arctic Shelf Exchange Study (CASES) 2003-04 expedition. Visibilities at two heights, wind and temperature profiles, plus blowing and drifting snow particle flux at several heights were monitored continually during the study period. Good relations between visibility and wind speed were found in individual events of ground blowing snow with coefficients of determination >0.9. Regression equations relating 1.5-m height visibility to 10-m wind speed can be used for predicting visibility with a mean relative error in the range of 19%-32%. Similar regression functions obtained from the data for observed visibility of less than 1 km could predict visibilities more accurately for more extreme visibility reductions and wind speeds (>9.5 m/s) with mean relative error ranging from 15% to 26%. For the event of ground blowing snow, a simple power law relationship between wind speed and visibility is sufficient for operational purposes. A poorer relationship was observed in the event of blowing snow with concurrent precipitating snow. A theoretical visibility model developed by Pomeroy and Male fit well with observed visibilities if using a mean radius of 50 µm and an alpha value of 10. The predicted visibility had a mean relative error of 30.5% and root-mean-square error of 1.3 km. The observed visibility at 1.5 m had a strong relation with particle counter readings, with an R² of 0.92, and was consistent among all events. (Au)

F, E, G
Atmospheric temperature; Blowing snow; Crystals; Density; Light; Mathematical models; Sea ice; Size; Snow; Snow cover; Snow water equivalent; Snowdrifts; Snowfall; Spatial distribution; Surface properties; Thickness; Velocity; Visibility; Weather forecasting; Winds

G0815
Franklin Bay, N.W.T.


Pixel-scale evaluation of SSM/I sea-ice algorithms in the marginal ice zone during early fall freeze-up   /   Hwang, B.J.   Barber, D.G.
(Hydrological processes, v. 20, no. 9, 15 June 2006, p.1909-1927, ill., maps)
References.
ASTIS record 60642.
Languages: English
Web: doi:10.1002/hyp.5958
Libraries: ACU

Observed reduction in recent sea ice areal extent and thickness has focused attention on the fact that the Arctic marine system appears to be responding to global-scale climate variability and change. Passive microwave remote-sensing data are the primary source underpinning these reports, yet problems remain in geophysical inversion of information on ice type and concentration. Uncertainty in sea-ice concentration (SIC) retrievals is highest in the summer and fall, when water occurs in liquid phase within the snow-sea-ice system. Of particular scientific interest is the timing and rate of new ice formation due to the control that this form of sea ice has on mass, energy and gas fluxes across the ocean-sea-ice-atmosphere interface. In this paper we examine the critical fall freeze-up period using in situ data from a ship-based and aerial survey programme known as the Canadian Arctic Shelf Exchange study combined with microwave and optical Earth observations data. Results show that: (1) the overall physical conditions observed from aerial survey photography were well matched with coincident moderate-resolution imaging spectroradiometer data and Radarsat ScanSAR imagery; (2) the shortwave albedo was linearly related to old ice concentration derived from survey photography; (3) the three SSM/I SIC algorithms (NASA Team (NT), NASA Team 2 (NT2), and Bootstrap (BT)) showed considerable discrepancies in pixel-scale comparison with the Radarsat ScanSAR SICs well calibrated by the aerial survey data. The major causes of the discrepancies are attributed to (1) the inherent inability to detect the new thin ice in the NT and BT algorithms, (2) mismatches of the thin-ice tie point of the NT2 algorithm, and (3) sub-pixel ambiguity between the thin ice and the mixture of open water and sea ice. These results suggest the need for finer resolution of passive microwave sensors, such as AMSR-E, to improve the precision of the SSM/I SIC algorithms in the marginal ice zone during earlyfall freeze-up. (Au)

G, E, D, A
Aerial surveys; Albedo; Canadian Arctic Shelf Exchange Study; Classification; Climate change; Energy budgets; Formation; Frazil ice; Grease ice; Ice cover; Mathematical models; Ocean-atmosphere interaction; Optical properties; Quality assurance; SAR; Satellite photography; Satellites; Sea ice; Seasonal variations; Snow cover; Special Sensor Microwave/Imager; Surface properties; Temporal variations; Thickness; Ultraviolet radiation

G0815
Franklin Bay, N.W.T.


Relationships between albedo and microwave emissions over thin newly formed sea ice during fall freeze-up   /   Hwang, B.J.   Ehn, J.K.   Barber, D.G.
(Geophysical research letters, v. 33, no. 17, L17503, Sept. 2006, 5 p., ill., maps)
References.
ASTIS record 62067.
Languages: English
Web: doi:10.1029/2006GL027300
Libraries: ACU

This study examines the relationship between albedo and microwave emissions over thin newly formed Arctic sea ice using in-situ measurements collected 19 Oct - 13 Nov 2003 in the Cape Bathurst Polynya, southern Beaufort Sea. Regression analysis show that statistically significant relationships exist between the microwave polarization ratio (PR(19)) and sea ice albedo. The albedo derived from the relationship with the PR(19) is compared to the albedo calculated from two parameterization schemes used in the climate models. The results show that the parameterized albedo significantly underestimates over thin ice or overestimates over thick snow-covered ice relative to both the in-situ and microwave-derived albedo. This study suggest that use of satellite passive microwave data should be considered in order to improve the treatment of surface albedo in regional climate models, in seasonal or marginal ice zones. (Au)

G, F, A
Albedo; Classification; Formation; Mathematical models; Measurement; Microwave radiation; Optical properties; Passive microwave remote sensing; Physical properties; Satellite photography; Sea ice; Slush; Snow; Spectroscopy; Surface properties; Surface temperature; Thickness

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Investigations of newly formed sea ice in the Cape Bathurst polynya : 2. Microwave emission   /   Hwang, B.J.   Ehn, J.K.   Barber, D.G.   Galley, R.   Grenfell, T.C.
(Journal of geophysical research, v.112, no. 5, C05003, May 2007, 14 p., ill.)
References.
ASTIS record 62071.
Languages: English
Web: doi:10.1029/2006JC003703
Libraries: ACU

This study examines the role of newly formed sea ice geophysical state on microwave emission. Coincident with sea ice geophysical sampling, ship-based passive microwave emission data (dual-polarized at 19, 37 and 85 GHz) were collected in the Cape Bathurst Polynya during 18 October and 13 November 2003. Using polarization ratios (PRs), we found that bare thin ice was separable from snow-covered ice. Thin snow (equal to 0.02-0.13 m) thickness is significantly correlated with the spectral gradient ratios GRV(85,19) (R² = 0.55, P-value <0.05) and GRV(85,37) (R² = 0.66, P-value < 0.05), but not with GRV(37,19) (R² = 0.19, P-value > 0.2). The relationship between atmospherically corrected R37 and bare ice thickness showed an exponential relationship very comparable to that reported by Martin et al. [2004] , which is ascribed to the reduction of bare ice surface salinity based on both observational and modeling studies. However, the relationship quickly becomes invalid for even thin snow covered ice, due to significant impact of thin wet (liquid water fraction 0.02-0.04) snow on microwave emission. Our results suggest that the sea ice algorithms NASA Team and NASA Team 2 could underestimate total ice concentration over thin bare ice by 35% on average, while both algorithms underestimate the total ice concentration by 20% over snow-covered ice. Using PR(85) sea ice could be delineated from open water using a properly adjusted threshold value accounting for cloud or fog effects, possibly with the exception of dark nilas and/or bare consolidated pancakes. (Au)

G, F, E, A
Atmospheric temperature; Classification; Electrical properties; Formation; Growth; Ice cover; Mathematical models; Measurement; Microwave radiation; Pancake ice; Passive microwave remote sensing; Physical properties; Polynyas; Salinity; Satellite photography; Sea ice; Slush; Snow; Surface properties; Temperature; Thermal properties; Thickness; Water content of snow

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


On detection of the thermophysical state of landfast first-year sea ice using in-situ microwave emission during spring melt   /   Hwang, B.J.   Langlois, A.   Barber, D.G.   Papakyriakou, T.N.
(Remote sensing of the cryosphere : special issue / Edited by Marco Tedesco. Remote sensing of environment, v.111, no. 2-3, 30 Nov. 2007, p. 148-159, ill., maps)
References.
ASTIS record 63299.
Languages: English
Web: doi:10.1016/j.rse.2007.02.033
Libraries: ACU

In this study we examine the critical linkages between thermophysical properties and microwave emissions of landfast snow-covered first-year sea ice during spring melt. For this we analyzed the temporal evolution of radiation fluxes, electro-thermophysical properties and microwave emissions, and perform model simulations to evaluate the observations. The results show five major microwave signature events: brine-rich, blowing snow, melt onset, the onset of funicular regime, and freezing. A brine-rich snow basal layer can considerably increase the snow wetness in the upper and mid layers, resulting in a significant increase in complex permittivity that in turn increases in polarization difference (delta rho) at 19 and 37 GHz. A dense (0.40 g/cm³) wind-packed snow surface layer, during a blowing snow event, was found to increase the permittivity (i.e., surface reflectivity) that in turn increases delta rho in microwave emissions. Melt onset caused by sustained warming (above -5°C) corresponded to increased delta rho of ~9 K at 19 GHz. The most dramatic increase in delta rho (up to 17 K at 19 GHz) coincided with the occurrence of a rainstorm. During a freezing, melt-freeze events enlarged snow grains and led to formation of ice lenses and layers within the snow, thereby significantly decreasing microwave emissions. We found that these five factors stated above were critical to the melt indicators (i.e., DeltaTB(H) (TB(19H) - TB(37H)) and XPGR ([TB(19H) - TB(37V)]/[TB(19H) + TB(37V)])) commonly used in the satellite melt detection algorithms. The results suggest that the absolute value of TB(19H) (brightness temperature of horizontal polarization at 19 GHz) would be a good indicator along with DeltaTB(H) (or XPGR) to delineate the melt onset from ambiguous factors (i.e., a brine-rich slush layer or wind-packed layer), and that the funicular stage of snow melt on sea ice could be unambiguously detected by either DeltaTB(H) or XPGR. (Au)

G, F, E, J, D
Atmospheric temperature; Blowing snow; Density; Detection; Diurnal variations; Electrical properties; Energy budgets; Fast ice; Instruments; Mathematical models; Melting; Microwave radiation; Ocean-atmosphere interaction; Optical properties; Passive microwave remote sensing; Physical properties; Radiation budgets; Rain; Salinity; Snow; Snow cover; Snow metamorphism; Snowmelt; Special Sensor Microwave/Imager; Surface properties; Surface temperature; Temporal variations; Thermal properties; Thermodynamics; Thickness; Water content of snow

G0815
Franklin Bay, N.W.T.


Passive microwave signatures of autumnal sea ice types from ship-based observation   /   Hwang, B.J.   Ehn, J.K.   Galley, R.   Barber, D.G.
In: IGARSS Barcelona 2007 : sensing and understanding our planet : IEEE International Geoscience and Remote Sensing Symposium : advance program : 23-27 July 2007, Centre de Convencions Internacional de Barcelona. - Piscataway, N.J. : Institute of Electrical and Electronics Engineers, 2007, p.4245-4248, ill., maps
References.
Indexed a PDF file from the Web.
ASTIS record 63909.
Languages: English
Web: doi:10.1109/IGARSS.2007.4423788
Libraries: ACU

Surface-scale passive microwave signatures of newly formed sea ice were collected using ship-based radiometers in the Southern Beaufort Sea and Amundsen Gulf between mid October and mid November 2003. Sea ice in the region was highly spatially and temporally variable. Over a heterogeneous area of open water and thin ice, polarization ratios showed multimodal frequency distributions and the differences between surface and satellite radiometric data were large. However, differences were small over a homogeneous area of snow-covered first-year ice during late fall and the corresponding histograms showed unimodal distributions. Our results suggest that subpixel heterogeneity is a critical factor in characterizing the mixture rules used in passive microwave sea ice algorithms. (Au)

A, G, F, Y
Boundaries; Electronic data processing; Formation; Frazil ice; Pack ice; Pancake ice; Passive microwave remote sensing; Photography; Satellites; Sea ice; Snow; Spatial distribution; Special Sensor Microwave/Imager; Thickness

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Retrieval of geophysical and thermodynamic state information from time series microwave radiometry in the fall and spring periods over Arctic sea ice   /   Hwang, B.J.   Barber, D.G. [Supervisor]
Winnipeg, Man. : University of Manitoba, c2007.
xxii, 334 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR36265)
ISBN 978-0-494-36265-5
Thesis (Ph.D.) - University of Manitoba, Winnipeg, Man., c.2007.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
Appendix.
References.
Also available through University of Manitoba library MSpace.
ASTIS record 74809.
Languages: English
Web: http://hdl.handle.net/1993/21065
Web: http://www.collectionscanada.gc.ca/obj/thesescanada/vol2/002/NR36265.PDF
Libraries: OONL MWU

The Arctic is regarded as a herald to global climate mainly because of strong interactions between the Arctic sea ice and the climate system. Understanding the roles of sea ice in the climate system is therefore critical in improving our knowledge of past and future climate changes on our planet. The primary objective of my dissertation is to investigate the utility of microwave radiometry in understanding how sea ice in the marine cryosphere evolves seasonally and how it responds to climate forcing. I conducted intensive field measurements of sea ice microwave and thermophysical/radiative properties during fall 2003 and spring 2004 in the southern Beaufort Sea and the Amundsen Gulf. The field data were carefully analyzed to address 1) surface-scale interactions between passive microwave signatures and thermophysical/radiative properties of snow/sea ice during fall and spring periods, and 2) spatial scaling issues associated with large footprint sizes of satellite microwave radiometers. The surfacescale fall studies revealed three significant correlations between microwave brightness temperature ratios and thermophysical/radiative properties of newly formed sea ice: microwave-ice thickness, microwave-brine volume and microwave-albedo. The first correlation confirmed the robustness of a previously reported thin ice thickness algorithm. The second correlation was found between microwave emissivity and brine volume on bare thin ice (R²~0.8, p-value<0.05). The physical causes for these two correlations were attributed to changes in ice salinity and temperature (i.e., changes in brine volume) and their significant controls on microwave brightness temperatures. A strong correlation between microwave PR(19) and sea.ice albedo (R²~0.96) was found, which has never been reported in the literature. The surface-scale spring study showed the five events ('brine-rich', 'blowing snow', 'melt onset', 'funicular' and 'freezing') that significantly affected microwave-thermophysical interactions. I found that melt onset signals can easily get confused with the signals from 'brine-rich' and 'blowing-snow' events when using melt detection indices (i.e., Delta TB(H) and XPGR). The results indicated an additional index (i.e., TB(19H)) would be useful to detect melt onset without ambiguity. From spatial scaling studies, I found significant errors in estimating sea ice concentrations occurred over homogeneous thin ice types, even before considering the effects of spatial heterogeneity. In comparative studies between surface-scale and satellite-scale measurements, I found that the linear mixing rule used in sea ice algorithms might not be valid to account for the satellite-scale brightness temperatures over mixed areas of open water and ice. Comparative studies between aircraft-scale and satellite-scale data showed the microwave brightness temperatures over thin ice dominant areas could not be distinguished from those over heterogeneous areas of open water and thicker ice. The studies also showed the difference in spatial resolution between AMSR-E and SSM/I became large in heterogeneous surfaces, which might be useful in estimating spatial heterogeneity at the surface. The results of my dissertation refined the extents and limitations of the utility of microwave radiometry in monitoring the fall/spring ice evolution processes in seasonal ice zones. To maximize the utility of microwave radiometry, however, new approaches should be considered, which include a combination of microwave radiometry and numerical climate/sea ice models. (Au)

F, G, E, J, D
Ablation; Aerial photography; Albedo; Atmospheric temperature; Blowing snow; Breakup; Climate change; Crystals; Effects of climate on ice; Energy budgets; Formation; Heat transmission; Ice fog; Mathematical models; Measurement; Melting; Ocean temperature; Ocean-atmosphere interaction; Passive microwave remote sensing; Physical properties; Polynyas; Quality assurance; Radiation budgets; Salinity; Sea ice; Seasonal variations; Snow; Snow cover; Snow metamorphism; Snow water equivalent; Solar radiation; Surface properties; Temporal variations; Thermal properties; Thermodynamics; Theses; Thickness; Water content of snow

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Impact of ice temperature on microwave emissivity of thin newly formed sea ice   /   Hwang, B.J.   Ehn, J.K.   Barber, D.G.
(Journal of geophysical research, v.113, no. C2, C02021, Feb. 2008, 10 p., ill., maps)
References.
ASTIS record 65871.
Languages: English
Web: doi:10.1029/2006JC003930
Libraries: ACU

This study examines the impact of ice temperature on microwave emissivity over thin, newly formed sea ice at 6, 19, and 37 GHz during October 2003 in the southern Beaufort Sea, where the physical properties of newly formed sea ice were coincidently measured with microwave emissions. Six ice stations with distinct properties were selected and divided according to ice surface temperature into warm (above -3°C) or cold (below -3°C) stations. The warm stations had a lower emissivity at the vertical polarization by 0.1 than the cold stations and a corresponding difference in brine volume and dielectric properties. Significant correlations were observed between brine volume and ice emissivity (R²= 0.8, p value <0.05). A sensitivity study showed that decreasing ice temperatures from -2.1° to -5.0°C explained the observed difference of 0.1 in ice emissivity between warm and cold stations. The results suggest that the temperature of thin bare ice could be the critical factor in determining ice emissivity near the melting point (about -2°C). Furthermore, a slight decrease in ice temperature (i.e., from -2° to -5°C) significantly reduces the brine volume, thus resulting in high ice emissivity. Finally, we demonstrate the potential of newly formed ice to cause errors in estimating sea ice concentrations using Advanced Microwave Scanning Radiometer-E data. (Au)

G, E, F, A
Atmospheric temperature; Boreholes; Electrical properties; Formation; Mathematical models; Microwave radiation; Passive microwave remote sensing; Physical properties; Salinity; Sea ice; Slush; Snow; Solar radiation; Surface properties; Temperature; Thickness; Velocity ; Winds

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


An examination of snow redistribution over smooth land-fast sea ice   /   Iacozza, J.   Barber, D.G.
(Hydrological processes, v. 24, no. 7, 30 Mar. 2010, p. 850-865, ill., maps)
References.
ASTIS record 74553.
Languages: English
Web: doi:10.1002/hyp.7526
Libraries: ACU

An understanding of temporal evolution of snow on sea ice at different spatial scales is essential for improvement of snow parameterization in sea ice models. One of the problems we face, however, is that long-term climate data are routinely available for land and not for sea ice. In this paper, we examine the temporal evolution of snow over smooth land-fast first-year sea ice using observational and modelled data. Changes in probability density functions indicate that depositional and drifting events control the evolution of snow distribution. Geostatistical analysis suggests that snowdrifts increased over the study period, and the orientation was related to the meteorological conditions. At the microscale, the temporal evolution of the snowdrifts was a product of infilling in the valleys between drifts. Results using two shore-based climate reporting stations (Paulatuk and Tuktoyuktuk, NWT) suggest that on-ice air temperature and relative humidity can be estimated using air temperature recorded at either station. Wind speed, direction and precipitation on ice cannot be accurately estimated using meteorological data from either station. The temporal evolution of snow distribution over smooth land-fast sea ice was modelled using SnowModel and four different forcing regimes. The results from these model runs indicate a lack of agreement between observed distribution and model outputs. The reasons for these results are lack of meteorological measurements prior to the end of January, lack of spatially adequate surface topography and discrepancies between meteorological variables on land and ice. (Au)

F, G, E
Atmospheric humidity; Atmospheric temperature; Density; Energy budgets; Fast ice; Mathematical models; Snow; Snow water equivalent; Snowdrifts; Snowfall; Spatial distribution; Surface properties; Temporal variations; Thickness; Velocity; Weather stations; Winds

G0815, G0812
Franklin Bay, N.W.T.; McDougall Sound, Nunavut; Paulatuk, N.W.T.; Tuktoyaktuk, N.W.T.


Spatial and temporal evolution of snow-covered sea ice, with reference to polar bear habitat   /   Iacozza, J.   Barber, D.G. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2011.
xix, 217 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR78551)
References.
Thesis (Ph.D.) - University of Manitoba, Winnipeg, Man., 2011.
Indexed a PDF file from the Web.
ASTIS record 76362.
Languages: English
Libraries: OONL MWUC

This dissertation attempts to improve the understanding of spatial distribution and evolution of snow-covered sea ice as related to polar bear habitat. This will be accomplished at both the local (i.e. 1m spatial resolution) and regional scales (i.e. 100 km spatial resolution) for various types of first-year sea ice (FYI) through four primary objectives. The first primary objective (i.e. Chapter 3) examines the observed and modeled temporal evolution of snow over smooth FYI, as well as the estimation of on-ice meteorological conditions. Results suggest that increases in observed snowdrifts and changes to the orientation of the drifts are related to snowfall and drifting events. Modeling these changes over time using a spatially distributed snow model is not able to accurately estimate the snow distribution. As well, only the on-ice temperature and humidity can be estimated from land-based station data, limiting the modeling of snow over sea ice. The second primary objective (i.e. Chapter 4) extends this research to rough FYI types, more relevant to polar bear habitat. More specifically this objective studies the spatial pattern of snow distribution over rough ice and ridges and the relationship between ice roughness and meteorological conditions. Results suggest that ice roughness influences the magnitude of snow depth, while the wind direction during periods of snow deposition and/or blowing snow events will impact the spatial pattern. The third primary objective (i.e. Chapter 5) focuses on developing a more feasible method of deriving surface roughness. This objective attempts to use satellite imagery and texture analysis to derive surface roughness for snow-covered sea ice. Results suggest that a Gamma speckle reduction filter, coupled with a grey-level co-occurrence matrix texture measure (Entropy or Angular Second Moment) is able to account for more than 88% of the variability in the surface roughness. The final primary objective (i.e. Chapter 6) examines the temporal evolution and factors controlling the changes in sea ice characteristics over regional scale for a period from 1978 to 2002. Observed anomalies in sea ice characteristics within some of the polar bear subpopulations may be explained by thermodynamic and/or dynamic factors. Results suggest that published reduction in polar bear population and condition within the subpopulations co-occur with these observed changes in sea ice characteristics. (Au)

I, G, F, E, J
Albedo; Animal distribution; Animal health; Animal population; Climate change; Denning; Ice rubble fields; Marine ecology; Mathematical models; Meteorology; Ocean-atmosphere interaction; Passive microwave remote sensing; Polar bears; SAR; Sea ice; Seals (Animals); Snow; Snowdrifts; Spatial distribution; Surface properties; Temporal variations; Thermal properties; Thermodynamics; Theses; Topography; Weather stations; Wildlife habitat

G0815, G07, G081
Canadian Arctic; Canadian Arctic waters; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Polar ocean coastal boundaries pan-regional overview (P)   /   Ingram, R.G.   Carmack, E.   Mclaughlin, F.   Nicol, S.
In: The sea : ideas and observations on progress in the study of the seas. Volume 14 : the global coastal ocean : interdisciplinary regional studies and syntheses. Part A : panregional syntheses and the coasts of North and South America and Asia / Edited by Allan R. Robinson and Kenneth H. Brink. - Cambridge, Mass. : Harvard University Press, 2006, ch. 3, p. 61-81, ill., maps
Cover title of the larger work: The sea : the global coastal ocean : interdisciplinary regional studies and syntheses.
Abbreviated title of the larger work: The sea : ideas and observations on progress in the study of the seas, v. 14, part A.
Title page title of the larger work: The global coastal ocean : interdisciplinary regional studies and syntheses. Part A: Panregional syntheses and the coasts of North and South America and Asia. ... The sea : ideas and observations on progress in the study of the seas, volume 14, part A.
References.
ASTIS record 63322.
Languages: English
Libraries: ACU

Introduction: In this chapter, we will describe the different characteristics of the coastal shelf areas in both the Arctic and Antarctic Oceans. The general oceanography and some key features of the marine ecosystems in these two polar oceans are summarized from regional chapters in this volume and other sources. Physical, circulation and ice processes have been overviewed by Royer and Stabeno (1998 - Vol. 11 The Sea). The Antarctic Ocean has a solid core of land and ice at its inner boundary in contrast to the Arctic Ocean, with leaky land boundaries around its circumference. We begin with the Arctic Ocean, focusing on the major shelf areas and the important forcing functions for both physics and biology. After a description of the Antarctic Ocean shelf area, a comparison of the shelf areas in the two polar oceans is presented. The Arctic Ocean is an almost landlocked ocean with two large basins, separated by a ridge, around the periphery of the Arctic Ocean. There are seven major shelf areas: Barents Sea, Kara Sea, Laptev Sea, East Siberian Sea, Chukchi Sea, Beaufort Sea and the Canadian Arctic Archipelago .... The physical and biological characteristics of each shelf area depend on its depth, the volume of fresh water input, the flux and origin of ocean waters, and the seasonal variability of sea ice. Because the outer boundaries of the Arctic Ocean are ambiguous and subject to interpretation, this discussion will define the Arctic Ocean as bounded on the Atlantic side by a line from Norway to Svalbard, and across Fram Strait, and on the Pacific side by Bering Strait. As such, the total ocean area, including the Canadian polar continental shelf (Canadian Arctic Archipelago) is 11.56 x 10**6 km², 60% of which is continental shelf. The continental shelves range in width from about 100 km in the Beaufort Sea to more than 1000 km in the Barents Sea and the Canadian Archipelago. The average depth of the Beaufort and Siberian shelf is 50-100m, whereas that of the Barents Sea, East Greenland and Canadian Arctic Archipelago is 100-500m. (Au)

G, D, E, F, I, H, J
Albedo; Atmospheric temperature; Bathymetry; Biomass; Chemical oceanography; Climate change; Continental shelves; Density; Effects of climate on ice; Environmental impacts; Fast ice; Food chain; Heat transmission; Hydrology; Ice cover; Light; Marine ecology; Marine fauna; Marine flora; Melting; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Oceanography; Pack ice; Phytoplankton; Polynyas; Primary production (Biology); River discharges; Rivers; Runoff; Salinity; Satellite photography; Sea ice; Sea water; Seasonal variations; Sediment transport; Solar radiation; Surface temperature; Suspended solids; Temporal variations; Thermal regimes; Water masses; Zooplankton

G01
Alaskan Beaufort Sea; Antarctic Bottom Water; Antarctic Circumpolar Current; Antarctic waters; Arctic Ocean; Arctic waters; Baffin Bay-Davis Strait; Barents Sea; Bering Strait; Canada Basin, Arctic Ocean; Canadian Arctic Islands waters; Canadian Beaufort Sea; Chukchi Sea; Fram Strait; Karskoye More; Labrador Sea; Lancaster Sound, Nunavut; Laptevykh More; Nares Strait, Greenland/Nunavut; North Atlantic Ocean; North Water Polynya, Baffin Bay; Ross Sea, Antarctic regions; South Pacific Ocean; Vostochno-Sibirskoye More; Weddell Sea, Antarctic regions


Seasonal circulation over the Canadian Beaufort shelf   /   Ingram, R.G.   Williams, W.J.   van Hardenberg, B.   Dawe, J.T.   Carmack, E.C.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 2, p. 13-35, ill., maps
References.
ASTIS record 67476.
Languages: English
Libraries: ACU

... The Canadian Beaufort Shelf is a broad, shallow continental shelf (~120 km wide; ~530 km long) in the southeastern Beaufort Sea which stretches from the Mackenzie Trough to the Amundsen Gulf .... Its coastal boundary is defined by freshwater outflow from the Mackenzie River Delta, while its offshore boundary is the oceanic Beaufort Gyre. ... Surface waters originate from the Mackenzie River and ice melt. Deeper waters come from both the Pacific (40-220 m) and Atlantic (>200 m) Oceans .... Given these dissimilar sources, waters on the shelf have a wide range of physical and geochemical properties. ... we present here observations for water circulation on the outer shelf and upper slope of the Canadian Beaufort Shelf obtained from long-term moorings of current meters and temperature-salinity recorders. The dataset derives from current meter moorings which were deployed at 8 sites for one year on the Canadian Beaufort Shelf and in Amundsen Gulf in the fall of 2002. It also includes data from a larger mooring program at 17 sites undertaken in 2002-2003. ... A significant part of the physical oceanography component of the CASES project focused on using instrumented moorings to measure ocean currents and water mass properties. ... Many of these moorings were equipped with instrumentation to measure bio-geochemical parameters such as fluorescence, light levels and sediment flux. ... The general circulation pattern observed in the upper 100 m of the water column appears to follow bottom topography and be strongly linked to sea ice cover. Mean flows are much stronger and demonstrate higher variability during reduced (<50%) ice cover and open water conditions. ... Flows are generally towards the southwest at the shelf edge and seaward in Amundsen Gulf. At 200 m depth, the influence of sea ice cover is much less apparent. Cross-shelf flows along the Mackenzie Trough are quite evident in the upper 100 m. Synoptic wind and ice movement create stress on the surface of the ocean which produces upwelling and downwelling circulation on the shelf. ... Under upwelling-favourable wind stress, the Mackenzie plume separates from the coast along the Tuktoyaktuk Peninsula and is rapidly pushed offshore such that it can extend beyond the shelf break into the Beaufort Gyre. Under downwelling-favourable wind stress, the Mackenzie plume is pushed onshore and forms a coherent coastal current that flows toward Cape Bathurst. The fate of Mackenzie River water likely depends on the predominant wind stress during the spring/summer when the river flow is highest. During upwelling-favourable wind stress, upwelling across the shelf break will occur and is topographically-enhanced at Mackenzie Trough, Kugmallit Valley and Cape Bathurst. Along-shelf flow towards the southwest during upwelling-favourable wind stress enhances the Beaufort Gyre and retards the Beaufort Undercurrent. Conversely, during downwelling-favourable wind stress, there is along-shelf flow towards the northeast, and this retards the Beaufort Gyre and enhances the Beaufort Undercurrent. The role of the physical environment in triggering, facilitating or enhancing primary production is important. ... Any changes in the region's ice regime accompanying global climate change will likely have a determining impact on the mean and varying part of its circulation signal. ... (Au)

D, E, G, F, A, H, J
Algae; Atmospheric temperature; Breakup; Chlorophyll; Climate change; Density; Environmental impacts; Fast ice; Formation; Hydrography; Ice cover; Ice leads; Light; Marine ecology; Melting; Ocean currents; Ocean temperature; Oceanographic instruments; Oceanography; Pack ice; Photosynthesis; Phytoplankton; Plant growth; Plant nutrition; Polynyas; Primary production (Biology); River discharges; Salinity; Sea ice; Seasonal variations; Sediment transport; Snow; Solar radiation; Spatial distribution; Stamukhi; Stream flow; Submarine topography; Suspended solids; Temporal variations; Thickness; Tides; Velocity; Water masses; Winds

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Kugmallit Valley, Canadian Beaufort Sea; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


C-band polarimetric backscattering signatures of newly formed sea ice during fall freeze-up   /   Isleifson, D.   Hwang, B.   Barber, D.G.   Scharien, R.K.   Shafai, L.
(IEEE transactions on geoscience and remote sensing, v. 48, no. 8, Aug. 2010, p.3256-3267, ill., map)
References.
ASTIS record 71839.
Languages: English
Web: doi:10.1109/TGRS.2010.2043954
Libraries: ACU

A study of the polarimetric backscattering response of newly formed sea ice types under a large assortment of surface coverage was conducted using a ship-based C-band polarimetric radar system. Polarimetric backscattering results and physical data for 40 stations during the fall freeze-up of 2003, 2006, and 2007 are presented. Analysis of the copolarized correlation coefficient showed its sensitivity to both sea ice thickness and surface coverage and resulted in a statistically significant separation of ice thickness into two regimes: ice less than 6 cm thick and ice greater than 8 cm thick. A case study quantified the backscatter of a layer of snow infiltrated frost flowers on new sea ice, showing that the presence of the old frost flowers can enhance the backscatter by more than 6 dB. Finally, a statistical analysis of a series of temporal–spatial measurements over a visually homogeneous frost-flower-covered ice floe identified temperature as a significant, but not exclusive, factor in the backscattering measurements. (Au)

G, F, E, D
Albedo; Antennae; Atmospheric temperature; Classification; Cores; Crystals; Deformation; Electrical properties; Energy budgets; Formation; Frost action; Grease ice; Ice floes; Ice leads; Ice rubble fields; Identification; Measurement; Ocean waves; Ocean-atmosphere interaction; Optical properties; Pancake ice; Polynyas; Radar; Salinity; SAR; Satellites; Sea ice; Slush; Snow; Surface properties; Temperature; Temporal variations; Testing; Thermal regimes; Thermodynamics; Thickness; Water vapour; Winds

G0815
Amundsen Gulf, N.W.T.; M'Clintock Channel, Nunavut


Simulation and measurement techniques for microwave remote sensing of sea ice   /   Isleifson, D.K.   Shafai, L. [Supervisor]   Barber, D. [Co-Supervisor]
Winnipeg, Man. : University of Manitoba, c2011.
xii, 219 p. : ill., map ; 28 cm.
Thesis (Ph.D.) - University of Manitoba, Winnipeg, Man., 2011.
References.
Indexed a PDF file from the Web.
ASTIS record 74649.
Languages: English
Web: http://mspace.lib.umanitoba.ca/handle/1993/4812
Libraries: MWU OONL

This dissertation presents new research into the study of simulation and measurement techniques for microwave remote sensing of sea ice. We have embarked on a major study of the microwave propagation and scattering properties of sea ice in an attempt to link the physics of the sea ice medium to experimentally obtained concomitant scatterometer measurements. During our fieldwork, we studied the polarimetric backscattering response of sea ice, focusing on newly-formed sea ice under a large assortment of surface coverage. Polarimetric backscattering results and physical data for 40 stations during the fall freeze-up of 2003, 2006, and 2007 are presented. Analysis of the co-polarization correlation coefficient showed its sensitivity to sea ice thickness and surface coverage and resulted in a statistically significant separation of ice thickness into two regimes: ice less than 6 cm thick and ice greater than 8 cm thick. A case study quantified the backscatter of snow-infiltrated frost fl owers on new sea ice, showing that the presence of the frost flowers enhanced the backscatter by more than 6 dB. In our simulation work, an efficient method for simulating scattering from objects in multi-layered media was incorporated into a scattered-field formulation of the FVTD method. A total-field 1D-FDTD solution to the plane-wave propagation through multi-layered meda was used as a source. The method was validated for a TE-polarized incident-field through comparisons with other numerical techniques involving examples of scattering from canonically-shaped objects. Methods for homogenization of inhomogeneous media were developed and validated using well-known dielectric mixture models. A Monte Carlo Method for simulating scattering from statistically rough surfaces was developed and was validated through favorable comparison with the SPM method for rough surface scattering. Finally, we presented a new Monte Carlo Method for simulating sea ice remote sensing that utilized the framework of the FVTD method for scattering simulations. The modeling process was driven by actual physical measurements of sea ice, wherein dielectric and physics-based modeling techniques were employed. The method was demonstrated through a series of case studies where the scattering from newly-formed sea ice was simulated using a TE-polarized incident- eld. Good agreement between experimental scatterometer measurements and simulated results was obtained for co-polarized returns, whereas cross-polarized results indicated that more depolarizing features must be taken into account. (Au)

G, F, E, D
Albedo; Atmospheric temperature; Classification; Crystals; Density; Electrical properties; Energy budgets; Formation; Frost action; Grease ice; Ice floes; Ice fog; Identification; Mathematical models; Measurement; Ocean waves; Ocean-atmosphere interaction; Optical properties; Pancake ice; Physical properties; Polynyas; Radar; Remote sensing; Research stations; Salinity; SAR; Satellites; Sea ice; Sea water; Snow; Surface properties; Temperature; Temporal variations; Thermal regimes; Thermodynamics; Theses; Thickness; Water vapour; Winds

G0815
Bathurst, Cape, waters, N.W.T.; Canadian Arctic waters


A new clear-sky downward longwave radiative flux parameterization for Arctic areas based on rawinsonde data   /   Jin, X.   Barber, D.   Papakyriakou, T.
(Journal of geophysical research, v.111, no. 24, D24104, Dec. 2006, 7 p., ill., map)
References.
ASTIS record 63281.
Languages: English
Web: doi:10.1029/2005JD007039
Libraries: ACU

An improved downward longwave clear-sky radiative flux (LWd) parameterization was developed and evaluated with field measurements collected in two projects: the Collaborative Interdisciplinary Cryospheric Experiment in 2000 and the Canadian Arctic Shelf Exchange Study. The 722 operational upper air soundings collected in Resolute Bay in 2000 were used to develop this scheme. After comparing this new method with 11 previous schemes we conclude that our new scheme has the smallest mean bias error: -0.8 W/m² and -0.7 W/m² in two projects, while all of the schemes have similar correlation coefficients: 0.96 and 0.91. Our new method has a varying root-mean square error, depending on the seasonal background of sampling period; it decreases with the extension of the sampling period and the inclusion of multiple sampling seasons. (Au)

E, G, A, J
Aerosols; Air pollution; Atmospheric humidity; Atmospheric temperature; Balloons; Canadian Arctic Shelf Exchange Study; Cold weather performance; Collaborative Interdisciplinary Cryospheric Experiment; Energy budgets; Infrared radiation; Mathematical models; Measurement; Meteorological instruments; Meteorology; Numeric databases; Ozone; Passive microwave remote sensing; Quality assurance; Radiation budgets; Sea ice; Seasonal variations; Surface temperature; Temporal variations; Water vapour; Weather stations; Winds

G0815, G0813
Franklin Bay, N.W.T.; Truro Island, Nunavut


Detecting cloud vertical structures from radiosondes and MODIS over Arctic first-year sea ice   /   Jin, X.   Hanesiak, J.   Barber, D.
(Atmospheric research, v. 83, no. 1, Jan. 2007, p. 64-76, ill., map)
References.
ASTIS record 63279.
Languages: English
Web: doi:10.1016/j.atmosres.2006.03.003
Libraries: ACU

The cloud vertical structure (CVS) of Arctic clouds is analyzed with data mainly from radiosondes launched between November 2003 and June 2004 during the Canadian Arctic Shelf Exchange Study (CASES). The feasibility of using a radiosonde-based cloud detection method [Minnis, P., Yi, Y. Huang, J., and Ayers, K. 2005: Relationships between radiosonde and RUC-2 meteorological conditions and cloud occurrence determined from ARM data, J. Geophys. Res., 110, D23204, doi:10.1029/2005JD006005. MN05 hereafter] is evaluated. At temperatures between -35 and 5°C, the minimum probability (Pr) calculated from MN05 to detect a cloud layer is 68%. The infeasibility of MN05 in determining Arctic cirrus clouds is speculated to be due to the different freezing mechanisms at low temperatures (< 40°C) in polluted continental and clean Arctic environments. Based on these facts we present a modified scheme to determine CVS in this paper. 1) for low clouds, 51.6% of all samples are with cloud base height (CBH) < 500 m; 66.5% with cloud top height (CTH) < 1500 m and 80.6% with CTH < 2500 m; 54.7% with cloud vertical thickness (CVT) < 500 m and 73.6% with CVT < 1000 m; 2) for middle clouds, the CBH is almost evenly distributed between 1.8 and 4 km but 68% of all CTHs are at heights between 2000 and 5000 m. 17% of CTHs are above 8000 m and 47% CVTs are thinner than 1000 m and 67% thinner than 2000 m; 3) for high clouds, the frequency distributions of both CBH and CTH decrease with increasing height from 5000 to 8000 m but there are 41% CBHs between 9000 and 11,500 m. The MODIS-derived cloud top pressure (CTP) is compared with data from radiosondes. In general the MODIS CTP agrees well with that from radiosondes between the 400 and 700 hPa layer. MODIS underestimates CTP at heights between 700 and 950 hPa and overestimates CTP at lower layers (> 950 hPa). The underestimate and overestimate of atmospheric temperatures above and under the 950 hPa isobaric layer respectively is thought to be the cause of the differences. (Au)

E, G, A, J
Aerosols; Air pollution; Atmosphere; Atmospheric circulation; Atmospheric temperature; Balloons; Canadian Arctic Shelf Exchange Study; Clouds; Cold weather performance; Detection; Mathematical models; Meteorological instruments; Meteorology; Numeric databases; Passive microwave remote sensing; Quality assurance; Radiation budgets; Satellites; Sea ice; Seasonal variations; Size; Storms; Thermal regimes; Thermodynamics; Thickness; Water vapour

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Time series of daily averaged cloud fractions over landfast first-year sea ice from multiple data sources   /   Jin, X.   Hanesiak, J.M.   Barber, D.G.
(Journal of applied meteorology and climatology, v. 46, no. 11, Nov. 2007, p.1818-1827, ill.)
References.
ASTIS record 74266.
Languages: English
Web: doi:10.1175/2007JAMC1472.1
Libraries: ACU

The time series of daily averaged cloud fractions (CFs) collected from different platforms- two Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on Terra and Aqua satellites, the National Centers for Environmental Prediction (NCEP) model, a Vaisala 25K laser ceilometer, and ground-based manual observations (manobs)- above the winter camp of the Canadian Arctic Shelf Exchange Study (CASES) field experiment are analyzed in this study. Taking the manobs as standard, the authors conclude that 1) the NCEP products considerably underestimated CFs in spring (e.g., from April to May) and 2) the performance of two MODIS products depends on the variation of solar zenith angle (SZA). Aqua MODIS misrepresents the snow-covered surface as clouds with almost randomly distributed CFs during the dark winter [cos(SZA) < 0], leading to the overestimation of CFs in winter while Terra MODIS has good agreement with manobs. When 0.1 < cos(SZA) < 0.4, both MODIS products regularly misrepresent the snow-covered background as clouds, leading to the significant overestimation of CFs in late winter (February) and early spring (March). When cos(SZA) > 0.4, both MODIS products have good performance in detecting cloud masks over snow backgrounds. If the sky is slightly cloudy, surface-based meteorological observers tend to underestimate cloud amounts when there is a lack of light. Comparing the CFs from Terra and manobs, the authors conclude that this bias can be over 10%. Power spectral analysis and wavelet analysis show three results: 1) High clouds more frequently appear in winter than in spring with periods between 8 and 16 days, indicating their close connection with synoptic events. Current NCEP products can predict this periodicity but have a phase lag. 2) Middle and low clouds are more local and are common in mid- and late spring (April and May) with periods between 2 and 4 days. At the CASES winter and spring field site, the periodicity of high clouds is dominant. 3) Thetime-scale-dependent correlation coefficients (CCs) between both MODIS products, NCEP and manobs, show that with high frequent CF sampling per day, the CCs are stable when the time scale varies between 1 and 4 days: with Terra MODIS and NCEP, the value is about 0.6; with Aqua MODIS, between 0.4 and 0.5. All CCs get smaller when the time scale increases beyond 8 days: with respect to both MODIS products, the CCs get closer with values between 0.3 and 0.4; with respect to NCEP, the CC dramatically decreases from positive values to negative values, indicating the lack of accuracy in current NCEP cloud schemes. (Au)

G, E, A
Albedo; Canadian Arctic Shelf Exchange Study; Clouds; Databases; Detection; Diurnal variations; Infrared radiation; Instruments; Meteorology; Radiation budgets; Satellite photography; Satellites; Sea ice; Seasonal variations; Snow cover; Surface properties; Temporal variations; Thermal properties

G0815
Franklin Bay, N.W.T.


Variations spatiales et temporelles de la sédimentation sous la zone euphotique dans le secteur canadien de la mer de Beaufort = Spatial and temporal patterns of sedimentation below the euphotic zone in the Canadian Beaufort Sea   /   Juul-Pedersen, T.   Rochon, A. [Supervisor]   Tremblay, J.-É. [Supervisor]
Rimouski, Québec : Université du Québec à Rimouski, 2007.
xiv, 145 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR35378)
ISBN 978-0-494-35378-3
References.
Thesis (Ph.D.) - Université du Québec à Rimouski, Rimouski, Québec, 2007.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
Abstract provided in French and English.
Chapters 1-3 are presented and also published in the form of journal articles: the first chapter is published in Marine Ecology Progress Series and described in ASTIS record 63912; chapter 2 is described in ASTIS record 65236, and Chapter 3 in ASTIS record 73169.
Cover title in French although text is in English.
ASTIS record 74974.
Languages: English
Web: http://semaphore.uqar.ca/350/
Libraries: OONL QRU

The sedimentation of particulate material was assessed under first-year sea ice and in open waters in the Canadian Beaufort Sea. Seasonal patterns of particulate material sinking export were studied throughout the ice algal productive period, from late winter to spring melt, targeting the upper water column near the bottom surface of the sea ice (down to 25 m). In open waters, spatial patterns in the sinking export of particulate material from the euphotic zone were related to key features of this region, i.e. the influence of Mackenzie River and the Cape Bathurst Polynya. The underice component of this study showed a close coupling between the increasing ice algal biomass and the sedimentation of algal material in spring, prior to the onset of ice melt. In addition, we observed a large contribution of non-algal material to the sinking flux of material. This research also showed significant transformation of the sedimenting algal material in the upper 25 m of the water column. Spring melt induced the termination of the ice algal productive period, as shown by a strong increase in the sedimentation of organic material associated with the release of ice biomass. Passive sinking export of material across the ice-water interface is generally considered to be related to ice melt. Our results challenge this view, even if the spring melt period showed maximum sedimentation. The spatial investigation during ice-free conditions revealed comparable seasonal ranges of sinking export of particulate organic material between the region influenced by the Mackenzie River and the Cape Bathurst polynya. A general seasonal decrease in the sinking export of particulate organic material was observed from summer to fall throughout this study. This research also found that a strong seasonal phytoplankton species succession prevailed in the Canadian Beaufort Sea, regardless of the spatial and interannual differences between sampling stations. A comparison of the sinking export of particulate organic material at a landfast station, during the ice covered period and subsequent ice-free conditions, emphasized the importance of underice sinking export of particulate organic material, particularly during spring melt. (Au)

D, H, G, J, F, I
Algae; Animal food; Animal waste products; Biological sampling; Biomass; Carbon; Carbon cycling; Chlorophyll; Continental shelves; Copepoda; Diatoms; Fast ice; Fluorometry; Grazing; Ice cover; Marine ecology; Nitrogen; Ocean temperature; Photosynthesis; Phytoplankton; Plant nutrition; Primary production (Biology); Protozoa; River discharges; Salinity; Sea ice; Seasonal variations; Sediment transport; Silica; Spatial distribution; Spectroscopy; Suspended solids; Temporal variations; Theses; Trophic levels; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Seasonal changes in the sinking export of particulate material under first-year sea ice on the Mackenzie shelf (western Canadian Arctic)   /   Juul-Pedersen, T.   Michel, C.   Gosselin, M.   Seuthe, L.
(Marine ecology. Progress series (Halstenbek), v.353, Jan. 17, 2008, p. 13-25, ill., maps)
References.
ASTIS record 63912.
Languages: English
Web: doi:10.3354/meps07165
Libraries: OON

The sinking export of particulate material under landfast first-year sea ice was studied from the winter period to spring melt on the Mackenzie Shelf, western Canadian Arctic. Short-term particle interceptor traps were deployed at 1, 15, and 25 m under the ice on 16 consecutive occasions from 23 February to 20 June 2004. The sinking material was analyzed for chlorophyll (chl) a, phaeopigments, total particulate carbon (TPC), particulate organic carbon and nitrogen (POC and PON), and biogenic silica (BioSi). The sinking fluxes of chl a and BioSi increased steadily after 19 March and until the onset of spring melt (26 May), after which they increased considerably. The contribution of large algae (>5 µm) to the total chl a sinking flux also increased after 19 March, reflecting an increasing contribution of diatoms to the sinking export of algal material. Accordingly, chl a sinking fluxes at 1 m showed a significant linear relationship with bottom ice chl a biomass. On average, 46% of the chl a exported at 1 m was lost in the upper 25 m. POC was the main component of the TPC sinking fluxes throughout the study. POC sinking fluxes remained fairly stable until the onset of spring melt, after which a considerable increase was observed. High POC:chl a ratios indicated a significant contribution of non-algal material to the sinking POC. The daily sinking loss rate of chl a, POC, and PON from the sea ice and interfacial layer (top 1 m of the water column) varied seasonally and was highest during the winter period. Our results illustrate the continuous downward sinking export of organic material under landfast ice, from winter throughout late spring. (Au)

G, D, H
Algae; Biomass; Carbon; Chlorophyll; Diatoms; Fast ice; Fluorometry; Formation; Melting; Nitrogen; Sea ice; Seasonal variations; Sedimentation; Silica; Suspended solids

G0815
Amundsen Gulf, N.W.T.; Franklin Bay, N.W.T.


Influence of the Mackenzie River plume on the sinking export of particulate material on the shelf   /   Juul-Pedersen, T.   Michel, C.   Gosselin, M.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 810-824, ill., maps)
References.
ASTIS record 65236.
Languages: English
Web: doi:10.1016/j.jmarsys.2008.02.001
Libraries: ACU

We examined the influence of the Mackenzie River plume on sinking fluxes of particulate organic and inorganic material on the Mackenzie Shelf, Canadian Arctic. Short-term particle interceptor traps were deployed under the halocline at 3 stations across the shelf during fall 2002 and at 3 stations along the shelf edge during summer 2004. During the two sampling periods, the horizontal patterns in sinking fluxes of particulate organic carbon (POC) and chlorophyll a (chl a) paralleled those in chl a biomass within the plume. Highest sinking fluxes of particulate organic material occurred at stations strongly influenced by the river plume (maximum POC sinking fluxes at 25 m of 98 mg C/m²/d and 197 mg C/m²/d in 2002 and 2004, respectively). The biogeochemical composition of the sinking material varied seasonally with phytoplankton and fecal pellets contributing considerably to the sinking flux in summer, while amorphous detritus dominated in the fall. Also, the sinking phytoplankton assemblage showed a seasonal succession from a dominance of diatoms in summer to flagellates and dinoflagellates in the fall. The presence of the freshwater diatom Eunotia sp. in the sinking assemblage directly underneath the river plume indicates the contribution of a phytoplankton community carried by the plume to the sinking export of organic material. Yet, increasing chl a and BioSi sinking fluxes with depth indicated an export of phytoplankton from the water column below the river plume during summer and fall. Grazing activity, mostly by copepods, and to a lesser extent by appendicularians, appeared to occur in a well-defined stratum underneath the river plume, particularly during summer. These results show that the Mackenzie River influences the magnitude and composition of the sinking material on the shelf in summer and fall, but does not constitute the only source of material sinking to depth at stations influenced by the river plume. (Au)

F, D, J, I, H
Algae; Animal waste products; Appendicularia; Biological sampling; Biomass; Carbon; Chlorophyll; Continental shelves; Copepoda; Diatoms; Fluorometry; Nitrogen; Ocean temperature; Phytoplankton; River discharges; Salinity; Seasonal variations; Sediment transport; Sedimentation; Silica; Spatial distribution; Spectroscopy; Stream flow; Suspended solids; Tunicates; Zooplankton

G07
Canadian Beaufort Sea


Sinking export of particulate organic material from the euphotic zone in the eastern Beaufort Sea   /   Juul-Pedersen, T.   Michel, C.   Gosselin, M.
(Marine ecology. Progress series (Halstenbek), v.410, July 14, 2010, p. 55-70, ill., maps)
References.
ASTIS record 73169.
Languages: English
Web: doi:10.3354/meps08608

This paper presents an extensive spatial and temporal study of the sinking export of particulate organic material below the euphotic zone in the eastern Beaufort Sea. Free-drifting short-term particle interceptor traps were deployed, generally at 50 m, during fall 2002 and 2003, and summer 2004. The different regions of the sampling area, i.e. the Amundsen Gulf and the Mackenzie shelf and slope, showed similar ranges in the sinking export of chlorophyll a (chl a) and particulate organic carbon (POC) in fall, while regional differences were observed in summer. The 2 regions showed a general decreasing trend in sinking fluxes towards fall. The highest chl a and POC sinking fluxes during this study were therefore recorded during summer (3.6 and 258 mg/m²/d, respectively). A high retention of suspended biomass was observed throughout this study, i.e. low daily loss rates of suspended chl a and POC (both averaging ca. 1%/d) were observed. Still, the POC sinking export accounted for, on average, half of the particulate primary production throughout this study. Zooplankton, primarily copepods, played an important role in the sinking export of particulate organic material, particularly in the Amundsen Gulf. A cluster-based analysis of the sinking protist cell assemblage revealed a seasonal succession that prevailed over spatial and interannual differences between the stations sampled in the eastern Beaufort Sea. Flagellates dominated throughout the study area, while diatoms, dominated by Fragilariopsis cylindrus, showed a decreasing contribution to the sinking protist cell assemblage towards fall. The presence of the sea ice related pennate diatoms Nitzschia frigida and Navicula vanhoeffenii in the material collected during summer reflected an input of organic material from sea ice. Results from particle interceptor traps deployed at a station in Franklin Bay during ice-covered and ice-free conditions showed the importance of taking into account under-ice sinking fluxes (up to 115 mg C/m²/d for POC) for sinking export estimates on Arctic shelves. (Au)

H, I, J, G
Animal food; Animal waste products; Biomass; Carbon; Chlorophyll; Copepoda; Diatoms; Fast ice; Fluorometry; Grazing; Phytoplankton; Plant nutrition; Primary production (Biology); Protozoa; River discharges; Sea ice; Seasonal variations; Sedimentation; Spatial distribution; Suspended solids; Temporal variations; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Modeling vertical excursions of the redox boundary in sediments : application to deep basins of the Arctic Ocean   /   Katsev, S.   Sundby, B.   Mucci, A.
(Limnology and oceanography, v. 51, no. 4, July 2006, p. 1581-1593, ill.)
References.
ASTIS record 62008.
Languages: English
Web: doi:10.4319/lo.2006.51.4.1581
Libraries: ACU

A diagenetic reaction-transport model was used to simulate how the sediment redox boundary migrates in response to persistent or episodic changes in the deposition flux of degradable organic matter and, the concentration of oxygen in the overlying bottom water. The position of the redox boundary is represented by the depth of oxygen penetration. The simulations reveal that the position of the redox boundary in organic-poor sediments, such as those in the deep basins of the Arctic Ocean, is highly sensitive to the flux of organic matter: relatively small and/or brief increases in that flux can cause the redox boundary to migrate rapidly from deep within the sediment to within a few centimeters of the sediment-water interface. Reoxidation of the sediment column after such an event can take years. Redox fluctuations can redistribute solid-phase manganese within the sediment column and produce multiple concentration peaks in its depth profile on a decadal time scale. Manganese peaks observed in sediment cores from the deep basins of the Arctic Ocean do not necessarily correspond to the position of the redox boundary during previous climatic periods or reflect historical changes in manganese deposition rates. The model supports the hypothesis that the recent decrease in the Arctic ice cover has increased the flux of organic matter to the seafloor and moved the redox boundary close to the sediment-water interface. The presence of iron sulfides at depths significantly below the bioturbated layer suggests that either the Arctic sediments have been anoxic for millennia, or iron and sulfate are reduced at these depths by dissolved organic matter diffusing downward from the bioturbation zone. (Au)

D, B
Bottom sediments; Carbon; Chemical oceanography; Dissolved organic carbon; Geochemistry; Iron; Manganese; Mathematical models; Oxygen; Seasonal variations; Sedimentation; Sulphides; Suspended solids; Temporal variations

G03
Arctic Ocean


Perspectives on marine zooplankton lipids   /   Kattner, G.   Hagen, W.   Lee, R.F.   Campbell, R.   Deibel, D.   Falk-Petersen, S.   Graeve, M.   Hansen, B.W.   Hirche, H.J.   Jónasdóttir, S.H.   Madsen, M.L.   Mayzaud, P.   Müller-Navarra, D.   Nichols, P.D.   Paffenhöffer, G.-A.   Pond, D.   Saito, H.   Stübing, D.   Virtue, P.
(Canadian journal of fisheries and aquatic sciences, v. 64, no. 11, Nov. 2007, p.1628-1639)
References.
ASTIS record 74717.
Languages: English
Web: doi:10.1139/f07-122
Libraries: ACU

We developed new perspectives to identify important questions and to propose approaches for future research on marine food web lipids. They were related to (i) structure and function of lipids, (ii) lipid changes during critical life phases, (iii) trophic marker lipids, and (iv) potential impact of climate change. The first addresses the role of lipids in membranes, storage lipids, and buoyancy with the following key question: How are the properties of membranes and deposits affected by the various types of lipids? The second deals with the importance of various types of lipids during reproduction, development, and resting phases and addresses the role of the different storage lipids during growth and dormancy. The third relates to trophic marker lipids, which are an important tool to follow lipid and energy transfer through the food web. The central question is how can fatty acids be used to identify and quantify food web relationships? With the fourth, hypotheses are presented on effects of global warming, which may result in the reduction or change in abundance of large, lipid-rich copepods in polar oceans, thereby strongly affecting higher trophic levels. The key question is how will lipid dynamics respond to changes in ocean climate at high latitudes? (Au)

I, J, H, E, G
Animal food; Animal growth; Animal physiology; Animal reproduction; Biochemistry; Climate change; Copepoda; Density; Diatoms; Effects of climate on ice; Environmental impacts; Fatty acids; Food chain; Ice cover; Invertebrate larvae; Lipids; Marine biology; Metabolism; Phytoplankton; Sea ice; Sea ice ecology; Seasonal variations; Trophic levels; Zooplankton

G02, G15, G03
Antarctic waters; Arctic Ocean; Arctic waters


The structure of bacterial communities in the western Arctic Ocean as revealed by pyrosequencing of 16S rRNA genes   /   Kirchman, D.L.   Cottrell, M.T.   Lovejoy, C.
(Environmental microbiology, v. 12, no. 5, May 2010, p.1132-1143, ill.)
References.
ASTIS record 71849.
Languages: English
Web: doi:10.1111/j.1462-2920.2010.02154.x
Libraries: ACU

Bacterial communities in the surface layer of the oceans consist of a few abundant phylotypes and many rare ones, most with unknown ecological functions and unclear roles in biogeochemical processes. To test hypotheses about relationships between abundant and rare phylotypes, we examined bacterial communities in the western Arctic Ocean using pyrosequence data of the V6 region of the 16S rRNA gene. Samples were collected from various locations in the Chukchi Sea, the Beaufort Sea and Franklin Bay in summer and winter. We found that bacterial communities differed between summer and winter at a few locations, but overall there was no significant difference between the two seasons in spite of large differences in biogeochemical properties. The sequence data suggested that abundant phylotypes remained abundant while rare phylotypes remained rare between the two seasons and among the Arctic regions examined here, arguing against the 'seed bank' hypothesis. Phylotype richness was calculated for various bacterial groups defined by sequence similarity or by phylogeny (phyla and proteobacterial classes). Abundant bacterial groups had higher within-group diversity than rare groups, suggesting that the ecological success of a bacterial lineage depends on diversity rather than on the dominance of a few phylotypes. In these Arctic waters, in spite of dramatic variation in several biogeochemical properties, bacterial community structure was remarkably stable over time and among regions, and any variation was due to the abundant phylotypes rather than rare ones. (Au)

H, D, G, E
Bacteria; Bathymetry; Biomass; Chlorophyll; Climate change; Genetics; Light; Marine ecology; Mathematical models; Microbial ecology; Microorganisms; Ocean temperature; Plant distribution; Plant growth; Plant taxonomy; Primary production (Biology); Sea ice; Seasonal variations; Temporal variations

G07, G04
Beaufort Sea; Chukchi Sea; Franklin Bay, N.W.T.


The role of exopolymers in microbial adaptation to sea ice   /   Krembs, C.   Deming, J.W.
In: Psychrophiles : from biodiversity to biotechnology / Edited by R. Margesin, F. Schinner, J.-C. Marx, and C. Gerday. - Heidelberg, Germany : Springer-Verlag Berlin, 2008, ch. 15, p. 247-264, ill.
References.
ASTIS record 74725.
Languages: English
Libraries: ACU

... In this chapter, we pay particular attention to the small-scale physics and chemistry of the behavior of exopolymers at low temperatures, and specifically within the sea-ice matrix where multiple phases are present in the space of a microbe, influencing its ability to survive. The study of exopolymers and cold adaptation in ice still represents a largely unexplored frontier, so other literature is tapped, including that for biofilms, polymers, the food industry, and medicine. By condensing seemingly disparate information into one source focused on exopolymeric substances, we seek to illuminate new directions for understanding mechanisms of cold adaptation in the microbial world, lining the pathway with an appreciation of the physical-chemical complexities of multi-phase systems so well-represented by sea ice. ... Exopolymeric substances (EPS) are complex organic materials composed primarily of polysaccharides with carbon backbones of high molecular weight (1-3 × 10**5 Daltons). ... CONCLUSIONS. In focusing on small-scale processes and the ways in which EPS can influence them, we have attempted to capture the complexity of cold environments experiencing phase changes and the challenges faced by microbes inhabiting them. At the same time, it should be obvious that the production of EPS, precisely because they can alter the physical-chemical processes within a multi-phase system, represents a critical survival strategy for microbes in frozen systems. Not surprisingly, the whole genome sequence of a cold-adapted bacterium known from sea ice reveals a preponderance of genes related to production and export of widely diverse polymeric substances .... Perhaps the most unique aspect of exopolymer production as a cold-adaptive strategy is its extracellularity. Unlike intracellular adjustments to various forms of stress, exopolymers are released by microbes and often under circumstances when the return benefit is not immediate or even clear .... An important implication is that even organisms unable to produce exopolymers can benefit from pre-existing EPS in the parent solution that the freezing process then concentrates for them. The combination of active EPS producers and passive beneficiaries suggests the potential for consortial arrangements and activities in ice that can help to explain an observed diversity of metabolic processes. For example, the co-occurrence of anaerobic N2 production and photosynthesizing oxygen-producing algae in Arctic sea ice, which should be mutually exclusive microbial activities, can be explained by EPS creating heterogeneous microzones that allow for both processes .... Central to the microscale scenario within a cold, naturally formed, multi-phase system are the ever-present microbes, which can be viewed as heterogeneous reaction sites embedded in hydrogels of EPS. These hydrogels must accommodate the transport of all substrates, essential nutrients, chemical signals and cellular byproducts between the surrounding fluids and organismal reaction sites. In ice, the temperature and the original chemical composition of the parent solution will drive the multiphase dynamics of the system, but the microbes, in controlling the amount and composition of EPS produced in situ, have the possibility to continuously modify their surroundings to favorable advantage. A summary of the features and processes addressed in this chapter are brought together in a flow diagram ... where we view hydrogels as dynamic and semi-permeable gates that both protect microbes and regulate their exchanges with the brine phase of their cold environments. Future research on EPS and cold adaptation can profit from careful consideration of how these semi-permeable gates may work, in models, in laboratory experiments and in natural settings. (Au)

H, J, G, D
Adaptation (Biology); Algae; Bacteria; Carbohydrates; Chemical properties; Cold adaptation; Cold physiology; Diatoms; Formation; Growth; Microbial ecology; Microorganisms; Ocean temperature; Physical properties; Salinity; Salt; Sea ice; Sea ice ecology; Sugars

G02
Arctic waters


La carotte de classe   /   Laclau, J.P.   Morata, N.
In: International Polar Year Oslo Science Conference, 2010, 8-12 June. - [Oslo : Research Council of Norway, 2010], presentation no. EA11.6-5.5, [1] p.
Abstract of an oral presentation, taken from the USB flash drive distributed at the conference.
ASTIS record 71443.
Languages: English

"La carotte de classe, it's because one day one student made a mistake, in fact the student is me" explained Jeremy in front of a French television crew, that came to interview the class..." and instead of writing la carotte de glace (ice core), you know it is a tube of ice, I wrote la carotte de classe (classroom core) and we kept it as title for our book". In French there is a saying: A carrot helps a stubborn animal (donkey) to advance. This project was born from the collaboration of an elementary school teacher, Jean Pierre Laclau and his students (9-10 years old), with Nathalie Morata, a young doctoral scientist working on Arctic research. Nathalie came to the classroom various times to sensitize the children to her polar interests, research, and life as scientist. She also kept in touch with the children by email during her field work onboard the Canadian icebreaker, the Amundsen, sharing with them her experiences and answering their questions. Curious and constantly seeking knowledge, the students enjoyed letting Nathalie bring them onboard albeit virtually, and worked in class on various questions linked to polar regions, including global warming, ocean preservation, biodiversity, Inuit communities and much more. By writing a book of their stories on the ice, the students wanted to share their discoveries with all who were not luck enough to have this experience. They promoted themselves the book around their area, and the book was also presented to scientists and teachers in Canada, US, Spain and Norway. It is now translated in English and is enriched with working suggestions. This French-English version will be a powerful tool for supporting teaching at various levels. Keywords: outreach, education. (Au)

R, L, G, D, I, H
Children; Communication; Elementary education; Marine biology; Oceanography; Research; Scientists; Sea ice; Teachers; Telecommunication

G0815
Canadian Arctic waters


Saison d'éclosion et survie des stades larvaires et juvéniles chez la morue arctique (Boreogadus saida) du sud-est de la mer de Beaufort   /   Lafrance, P.   Fortier, L. [Supervisor]   Gagné, J. [Supervisor]
Québec, Québec : Université Laval, 2009.
xii, 80 p. : ill., maps ; 28 cm..
Thesis (Ph.D.) - Université Laval, Québec, Québec, 2009.
References.
Chapter 1: General introduction and Chapter 4: General conclusion are in French; core chapters (2 and 3) are in English.
ASTIS record 74980.
Languages: English or French
Web: http://archimede.bibl.ulaval.ca/archimede/meta/26145
Libraries: OONL

Arctic cod (Boreogadus saida) is widely distributed in circumpolar Arctic seawaters and plays an important role in transferring energy from lower trophic levels to higher predators in the Arctic marine food web. To limit vulnerability of young Arctic cod to predation and/or cannibalism at the end of short Arctic summers, reproductive strategy of this key species has evolved to reach the largest pre-winter size of cod juveniles. Two adaptative mechanisms strongly influence variability in survival of juvenile Arctic cod in relation to environmental conditions: the hatching season and early growth. In a changing Arctic climate that exhibits interannual variations and strong seasonality, hatching and growth dynamics of Arctic cod urgently need to be addressed. In this study, we first determined the individual hatch dates of juvenile Arctic cod sampled in southeastern Beaufort Sea during fall expeditions over a five-year period (2002-2006) and from April to August in 2004. The results suggest the existence of two distinct populations of larval Arctic cod in the study area. First, an inshore population that hatches early in winter (January to March) in the thermal refuge (T>= -0.47) provided by the estuarine waters of Mackenzie Lake extending under landfast ice. Second, an offshore population of delayed hatching (April to June) that coincide with the ice break-up and the vernal onset of biological productivity on the Mackenzie Shelf and in the Amundsen Gulf. The interannual variability (2002-2006) documented in hatching patterns of juvenile cod results from the relative importance of early-winter hatchers surviving each year and is partly related to variations in dominant environmental factor in the habitat. Overall, this study documents the reproductive strategy of Arctic cod in southeastern Beaufort Sea that aims to maximize size of juvenile at the onset of their first winter under the ice. (Au)

I, D, E, J, G, F
Adaptation (Biology); Animal distribution; Animal ecology; Animal food; Animal growth; Animal mortality; Animal population; Animal reproduction; Arctic cod; Beluga whales; Biological sampling; Breakup; Chlorophyll; Climate change; Environmental impacts; Fish larvae; Hydrography; Ice leads; Marine ecology; Measurement; Ocean temperature; Predation; River discharges; Sea ice; Seasonal variations; Size; Stamukhi; Stream flow; Temporal variations; Thermal regimes; Theses

G07, G0812, G03, G0815
Arctic Ocean; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.


On the winter evolution of snow thermophysical properties over land-fast first-year sea ice   /   Langlois, A.   Mundy, C.J.   Barber, D.G.
(Hydrological processes, v. 21, no. 6, 14 Sept. 2006, p. 705-716, ill., map)
References.
ASTIS record 63284.
Languages: English
Web: doi:10.1002/hyp.6407
Libraries: ACU

The geophysical, thermodynamic and dielectric properties of snow are important state variables that are known to be sensitive to Arctic climate variability and change. Given recent observations of changes in the Arctic physical system (Arctic Climate Impact Assessment, 2004), it is important to focus on the processes that give rise to variability in the horizontal, vertical and temporal dimensions of the life-history of snow on sea ice. The objectives in this study are to present these state variables and to investigate the processes that govern variability in the vertical, horizontal and temporal dimension by using a case study over land-fast first-year sea ice for the period December 2003 to June 2004. Results from two sampling areas (thin and thick snowpacks) show that differences in snowpack thickness can substantially change the vertical and temporal evolution of snow properties. During the late fall and early winter (cooling period) we measured no significant changes in the physical properties, except for thin snow-cover salinity, which decreased throughout the period. Fall-snow desalination was only observed under thin snowpacks with a rate of -0.12 ppt/day. Significant changes occurred in the late winter and early spring (warming period), especially for snow grain size. Snow grain kinetic growth of 0.25-0.48 mm/day was measured coincidently with increasing salinity and wetness for both thin and thick snowpacks. (Au)

F, G, E, J
Albedo; Canadian Arctic Shelf Exchange Study; Climate change; Density; Electrical properties; Energy budgets; Heat transmission; Hydrology; Ice cover; Mathematical models; Measurement; Meteorology; Ocean-atmosphere interaction; Physical properties; Radar; Radiation budgets; Salinity; SAR; Sea ice; Seasonal variations; Snow; Snow cover; Snow metamorphism; Temporal variations; Thermal properties; Thermodynamics; Thickness; Water content of snow

G0815
Franklin Bay, N.W.T.


Development of a winter snow water equivalent algorithm using in situ passive microwave radiometry over snow-covered first-year sea ice   /   Langlois, A.   Barber, D.G.   Hwang, B.J.
(Remote sensing of environment, v.106, no. 1, 15 Jan. 2007, p. 75-88, ill., maps)
References.
ASTIS record 63285.
Languages: English
Web: doi:10.1016/j.rse.2006.07.018
Libraries: ACU

A snow water equivalent (SWE) algorithm has been developed for thin and thick snow using both in situ microwave measurements and snow thermophysical properties, collected over landfast snow covered first-year sea ice during the Canadian Arctic Shelf Exchange Study (CASES) overwintering mission from December 2003 to May 2004. Results showed that the behavior of brightness temperatures (Tbs) in thin snow covers was very different from those in a thick snowpack. Microwave SWE retrievals using the combination of Tb 19 GHz and air temperature (multiple regression) over thick snow are quite accurate, and showed very good agreement with the physical data (R² = 0.94) especially during the cooling period (i.e., from freeze up to the minimum air temperature recorded) where the snow is dry and cold. Thin snow SWE predictions also showed fairly good agreement with field data (R² = 0.70) during the cold season. The differences between retrieved and in situ SWE for both thin and thick snow cover are mainly attributable to the variations in air temperature, snow wetness and spatial heterogeneity in snow thickness. (Au)

F, G, E, J
Albedo; Atmospheric temperature; Climate change; Energy budgets; Heat transmission; Mathematical models; Measurement; Ocean-atmosphere interaction; Passive microwave remote sensing; Physical properties; Quality assurance; Radiation budgets; Sea ice; Snow; Snow cover; Snow water equivalent; Temporal variations; Thermal properties; Thermodynamics; Thickness; Water content of snow

G0815
Franklin Bay, N.W.T.


Passive microwave remote sensing of seasonal snow-covered sea ice   /   Langlois, A.   Barber, D.G.
(Progress in physical geography, v. 31, no. 6, Dec. 2007, p. 539-573, ill.)
References.
ASTIS record 65884.
Languages: English
Web: doi:10.1177/0309133307087082
Libraries: ACU

The Arctic is thought to be an area where we can expect to see the first and strongest signs of global-scale climate variability and change. We have already begun to see a reduction in: (1) the aerial extent of sea ice at about 3% per decade and (2) ice thickness at about 40%. At the current rate of reduction we can expect a seasonally ice-free Arctic by midway through this century given the current changes in thermodynamic processes controlling sea-ice freeze-up and decay. Many of the factors governing the thermodynamic processes of sea ice are strongly tied to the presence and geophysical state of snow on sea ice, yet snow on sea ice remains poorly studied. In this review, we provide a summary of the current state of knowledge pertaining to the geophysical, thermodynamic and dielectric properties of snow on sea ice. We first give a detailed description of snow thermophysical properties such as thermal conductivity, diffusivity and specific heat and how snow geophysical/electrical properties and the seasonal surface energy balance affect them. We also review the different microwave emission and scattering mechanisms associated with snow-covered first-year sea ice. Finally, we discuss the annual evolution of the Arctic system through snow thermodynamic (heat/mass transfer, metamorphism) and aeolian processes, with linkages to microwave remote sensing that have yet to be defined from an annual perspective in the Arctic. (Au)

F, G, E
Albedo; Atmospheric temperature; Boundary layers; Climate change; Clouds; Crystals; Density; Depth hoar; Diurnal variations; Electrical properties; Energy budgets; Flow; Formation; Growth; Heat transmission; Movement; Passive microwave remote sensing; Physical properties; Puddles; Radiation budgets; Salinity; Satellites; Sea ice; Seasonal variations; Size; Snow; Snow metamorphism; Snow stratigraphy; Snow water equivalent; Snowmelt; Surface temperature; Temperature; Thermal properties; Thermodynamics; Thickness; Water content of snow; Water vapour; Winds

G02
Arctic regions


Development of snow water equivalent (SWE) algorithm over first-year ice using in situ passive microwave radiometry   /   Langlois, A.   Barber, D. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2007.
xviii, 242 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR41271)
ISBN 978-0-494-41271-8
Appendix.
References.
Thesis (Ph.D.) - University of Manitoba, Winnipeg, Man., 2007.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74975.
Languages: English
Libraries: OONL

The Arctic is thought to be an area where we can expect to see the first and strongest signs of global scale climate variability and change. We have already begun to see a reduction in: (i) the aerial extent of sea ice at about 3 percent per decade and (ii) ice thickness at about 40 percent. At the current rate of reduction we can expect a seasonally ice-free Arctic by midway through this century given the current changes in thermodynamic processes controlling sea ice freeze-up and decay. Many of the factors governing the thermodynamic processes of sea ice are strongly tied to the presence and geophysical state of snow, yet snow on sea ice remains poorly studied. In this dissertation, I present results from a snow water equivalent algorithm development study over first-year sea ice from the Canadian Arctic Shelf Exchange Study (CASES) overwintering mission in 2003-2004. The analysis provides the current state of knowledge pertaining to the geophysical, thermodynamic, and dielectric properties of snow on sea ice. A detailed analysis is first provided on snow thermophysical properties and the existing linkages with passive microwave scattering and emission mechanisms in a temporal evolution pattern. Results show that winter snow thickness has a significant impact on thermophysical properties as well as the seasonal surface energy balance. Winter thermodynamic processes such as desalination and snow metamorphism are more important than previously expected and their control on brightness temperatures through the dielectric properties can be significant. The known/found linkages between snow thermophysical properties and passive microwaves are employed to retrieve snow water equivalent (SWE). Predictions are significant throughout the season over evolving snow thickness with a R² of 0.95 with in-situ measured data. The developed algorithm is applied to satellite remote sensing and predicted SWE values statistically agree with in-situ validation measurements for two AMSR-E pixels located in the Franklin Bay region. (Au)

F, G, E, D
Albedo; Atmospheric humidity; Atmospheric pressure; Atmospheric temperature; Climate change; Clouds; Crystals; Density; Diurnal variations; Electrical properties; Energy budgets; Formation; Growth; Heat transmission; Mathematical models; Ocean temperature; Ocean-atmosphere interaction; Passive microwave remote sensing; Physical properties; Radiation budgets; Sea ice; Seasonal variations; Size; Snow; Snow cover; Snow metamorphism; Snow stratigraphy; Snow water equivalent; Solar radiation; Spatial distribution; Surface properties; Temperature; Temporal variations; Thermal properties; Thermodynamics; Theses; Thickness; Velocity; Water content of snow; Winds

G0815
Franklin Bay, N.W.T.


Response of snow thermophysical processes to the passage of a polar low-pressure system and its impact on in situ passive microwave radiometry : a case study   /   Langlois, A.   Fisico, T.   Barber, D.G.   Papakyriakou, T.N.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C3, C03S04, Mar. 2008, 17 p., ill.)
References.
ASTIS record 64591.
Languages: English
Web: doi:10.1029/2007JC004197
Libraries: ACU

Recent reductions in both the aerial extent and thickness of sea ice have focused attention on the effect climate change is having on the polar marine system. Concomitant with a reduction in sea ice has been an increased frequency of low-pressure depressions at high latitudes. Recent studies have shown that we can expect both increased in situ cyclogenesis and advection into the arctic region. Since these cyclones are associated with warm air advection, increased wind speed, relative humidity, and cloud cover, their impact on snow surface energy balance may be significant. The thermophysical response of snow-covered first-year sea ice to a low-pressure disturbance is investigated along with its impact on surface-based radiometer brightness temperature measurements. The data were collected during the Canadian Arctic Shelf Exchange Study (CASES) between year days 33 and 34 of 2004. Snow grain size increased throughout the sampling period with growth rates of 1.28 and 2.3 mm²/d for thin and thick snow covers, respectively. This rate was much faster than expected on the basis of other similar experiments documented in the literature. Furthermore, brine volume migrated upward in both snowpacks owing to the action of wind pumping affecting the dielectric constant of the snow middle layers. This increase in permittivity caused a decrease in brightness temperatures at 85 GHz of approximately 5 K and 10 K in the vertical and horizontal polarizations, respectively. This signal is sufficiently large to impact interpretation of passive microwave signatures from space. (Au)

F, E, G
Atmospheric humidity; Atmospheric pressure; Atmospheric temperature; Clouds; Crystals; Density; Diurnal variations; Electrical properties; Energy budgets; Fast ice; Growth; Heat transmission; Passive microwave remote sensing; Physical properties; Salinity; Sea ice; Size; Snow; Snow metamorphism; Storms; Surface properties; Temperature; Thermal properties; Thickness; Velocity; Water content of snow; Winds

G0815
Franklin Bay, N.W.T.


Estimation of snow water equivalent over first-year sea ice using AMSR-E and surface observations   /   Langlois, A.   Scharien, R.   Geldsetzer, T.   Iacozza, J.   Barber, D.G.   Yackel, J.
(Remote sensing of environment, v.112, no. 9, 15 Sept. 2008, p.3656-3667, ill., map)
References.
ASTIS record 65285.
Languages: English
Web: doi:10.1016/j.rse.2008.05.004
Libraries: ACU

A SWE retrieval algorithm developed in-situ using passive microwave surface based radiometer data is applied to the Advanced Microwave Scanning Radiometer for Earth Observation System (AMSR-E). Snow water equivalent is predicted from two pixels located in Canadian Arctic Shelf Exchange Study (CASES) overwintering study area in Franklin Bay, N.W.T., Canada. Results show that the satellite SWE predictions are statistically valid with measured in-situ snow thickness data in both smooth and rough ice environments where predicted values range from 15 to 25 mm. Stronger correlation between measured and predicted data is found over smooth ice with R² value of 0.75 and 0.73 for both pixels respectively. Furthermore, a qualitative study of sea ice roughness using both passive and active microwave satellite data shows that the two pixels are rougher than the surrounding areas, but the SWE predictions do not seem to be affected significantly. (Au)

F, G, A, E
Atmospheric temperature; Ice cover; Optical properties; Passive microwave remote sensing; SAR; Satellites; Sea ice; Seasonal variations; Snow; Snow water equivalent; Surface properties; Surface temperature; Temperature; Thickness

G0815
Franklin Bay, N.W.T.


Advances in seasonal snow water equivalent (SWE) retrieval using in situ passive microwave measurements over first-year sea ice   /   Langlois, A.   Barber, D.G.
(International journal of remote sensing, v. 29, no. 16, Aug. 2008, p.4781-4802, ill., map)
References.
ASTIS record 65287.
Languages: English
Web: doi:10.1080/01431160801908145
Libraries: ACU

Dramatic changes have occurred in the Arctic over the past three decades in response to an accelerated warming that will have a significant impact on the world's climate. Snow accumulation (measured as snow water equivalent, SWE) over sea ice plays a key role in the changes observed due to its effect on the surface energy balance that dictates the timing of sea-ice freeze-up and decay. Increased awareness of the role of snow in the Arctic system has triggered numerous studies that have attempted to characterize snow accumulation from space since the early 1980s, but none has successfully quantified SWE on a seasonal basis. This work presents the first seasonally valid SWE algorithm for first-year sea ice based on in situ passive microwave radiometry. The in situ data were collected as a part of the Canadian Arctic Shelf Exchange Study (CASES) during the overwintering mission of the Canadian Coast Guard Ship (CCGS) Amundsen in 2003-2004. Previous work clearly demonstrated two different patterns of seasonal snow evolution, for which the algorithm presented in this paper accounts for. Our algorithm's results are valid for temperatures between -5 and -30°C and SWE in the range of 0-55 mm. Results show that the behaviour of the snow's thermophysical properties and brightness temperatures (Tb) is quite different in the winter cooling period compared with that in the warming period, where temperature gradient metamorphism begins at a SWE value of 33 mm. The SWE algorithm successfully models this change with a high degree of correlation. (Au)

F, G, A, E
Atmospheric temperature; Clouds; Density; Optical properties; Passive microwave remote sensing; Physical properties; Radiation budgets; Salinity; Satellites; Sea ice; Seasonal variations; Size; Snow; Snow metamorphism; Snow stratigraphy; Snow water equivalent; Temperature; Thickness; Velocity; Water content of snow; Winds

G0815
Franklin Bay, N.W.T.


Circulation régionale, masses d'eau, cycles d'évolution et transports entre la mer de Beaufort et le golfe d'Amundsen   /   Lanos, R.   Gratton, Y. [Supervisor]
Saint-Foy, Québec : Université du Québec Institut National de la Recherche Scientifique, 2009.
xxiv, 245 p. : ill., maps ; 28 cm..
Thesis (Ph.D.) - Université du Québec Institut National de la Recherche Scientifique, Saint-Foy, Québec, 2009.
References.
Appendices.
ASTIS record 74981.
Languages: French
Web: http://www1.ete.inrs.ca/pub/theses/T000510.pdf
Libraries: OONL

La région d'étude du programme Canadian Arctic Shelf Exchange Study (CASES) est formée par le sud de la mer de Beaufort, les plateau et delta du fleuve Mackenzie et le golfe d'Amundsen. Entre 2002 et 2004, plusieurs campagnes océanographiques ont permis d'y acquérir un très grand nombre de données dans le but de mieux comprendre son fonctionnement et d'en envisager l'évolution future sous la pression des changements climatique globaux. Cet échantillonnage s'est poursuivit au cours des années 2005, 2006, 2007 et 2008 lors des campagnes réalisées sous l'égide du réseau ArcticNet. Dans la présente étude, un grand nombre de données issues de ces compagnes est utilisé pour générer une description régionale des propriétés de l'océan en termes de masses d'eau et de circulation, documenter le cycle annuel d'évolution des principaux paramètres océanographiques et évaluer les échanges entre la mer de Beaufort et le golfe d'Amundsen. La cartographie des champs de propriétés laisse apparaitre une forte hétérogénéité spatiale aux échelles locale et régionale. Cette observation est liée à la circulation, aux singularités bathymétriques ainsi qu'aux effets du seuil séparant la mer de Beaufort et le golfe d'Amundsen. Le schéma de circulation, mis en évidence pour la première fois dans le golfe d'Amundsen, fait apparaitre deux couches aux mouvements opposés, anticyclonique en surface, cyclonique au fond. Dans le sud de la mer de Beaufort les résultats présentés confirment les connaissances existantes et la présence d'un jet géostrophique en bordure du plateau continental. L'analyse spectrale des courants permet d'évaluer le rôle primordial joué par les mécanismes de résonance entre les fréquences inertielles et les harmoniques de marée semi-diurne, elle offre également une vision contrastée de l'effet du couvert de glace sur le contenu énergétique de ces courants. L'identification précise des masses d'eau présentent dans la région met en évidence la profondeur anormalement faible de la couche halocline qui permet le transfert d'une partie de la chaleur contenue dans les eaux issues du Pacifique vers les couches de surface. Le suivit du cycle annuel d'évolution de la colonne d'eau permet de documenter l'évolution de la Polar Mixed Layer au cours de l'année. Les résultats laissent ainsi apparaitre son épaississement pendant l'hiver, l'élévation très rapide de sa température eau début de l'été et son conditionnement à l'automne en vue de l'hiver suivant. Enfin, le calcul du flux volumique entre la mer de Beaufort et le golfe d'Amundsen montre que le golfe exporte plus d'eau vers l'Arctique qu'il n'en reçoit. L'estimation de ce transport (-0.19 ± 0.22 Sv) correspond à 10% du volume total transporté au travers de l'Archipel Arctique Canadien. Cette valeur montre le rôle non négligeable joué par la région dans la circulation et les échanges au sein de l'archipel. Ensemble, ces éléments portent un éclairage nouveau sur la région d'étude du programme CASES et permettent d'expliquer une part de l'hétérogénéité spatiale observée. A leur lecture, le golfe d'Amundsen n'apparait plus comme une simple dépendance de la mer de Beaufort, mais bien comme une région à part entière aux multiples particularités. Ils offrent également une base physique au nombreuses autres recherches océanographiques en cours et à venir. (Au)

D, G, E
ArcticNet Inc.; Bathymetry; Density; Ice cover; Ocean currents; Oceanography; Optical properties; Salinity; Seasonal variations; Spectroscopy; Surface temperature; Theses; Water masses

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea


Water mass distribution on the Mackenzie shelf and the Amundsen Gulf as determined by total alkalinity and delta 18O data   /   Lansard, B.   Mucci, A.   Miller, L.   Macdonald, R.W.   Thomas, H.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 108
Abstract of a Topical Session presentation.
Indexed a PDF file from the Web.
ASTIS record 66927.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Sea ice formation leads to brine rejection and contributes to the formation of dense water that sinks to intermediate and greater depths. Hence, high latitude areas can act as a sink for atmospheric CO2 and thus represent a direct pathway for CO2 exchange between the atmosphere and the deep ocean. The sites of deep water formation in the Canadian Arctic are unknown and the analysis of water masses is a first step towards this objective. During the Canadian Arctic Shelf Exchange Study (CASES) and the Circumpolar Flaw Lead project (CFL) an extensive dataset including total alkalinity (TA), dissolved inorganic carbon (DIC), pH and delta18O of seawater was collected on the Mackenzie Shelf and the adjacent Amundsen Gulf. This study area is a complex zone because of the interaction of numerous water masses, as revealed by temperature-salinity diagrams. The identification of water masses and their distribution within the study area was successfully accomplished using an optimum multi-parameter analysis (OMP) based on temperature, salinity, dissolved O2 concentrations, TA and delta18O. Surface waters (depth<100 m) display a strong seasonal variability and are composed of a mixture of the Polar Mixed Layer (PML), fresh water from the Mackenzie River (MW), and sea ice melt (SIM). Water originating from the Mackenzie River is characterized by low delta18O (-20‰) and low TA (<1600 µmol/kg) values whereas sea ice melting generates higher delta18O (-2.0‰) and very low TA (<400 µmol/kg). Below the upper halocline (depth>100m), three water masses are clearly identified. A first water mass is characterized by a 33.1 salinity and is of Pacific origin (PW). The PW layer has a mean TA of 2280 ±8 µmol/kg and a mean delta18O of -1.60 ±0.14‰. At 200 m depth, a strong thermocline separates the PW from the Atlantic layer water (ALW) which has mean TA and delta18O values of 2300 ±11 µmol/kg and 0.24 ±0.06‰, respectively. The Canadian basin deep water (CDW) is found below 1000 m depth in the Beaufort Sea and carries TA and delta18O values which are slightly higher than those of the ALW. This typical distribution is counter balanced by a seasonal and inter-annual variability which is mainly driven by meteorological conditions. In this presentation, we examine the water mass distribution, its modification and variability on the Mackenzie shelf with regards to the carbonate system. (Au)

D, G, F
Bathymetry; Carbon cycling; Chemical oceanography; Numeric databases; Ocean temperature; Ocean-atmosphere interaction; Oxygen-18; River discharges; Salinity; Sea ice; Sea water; Seasonal variations; Water masses

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canada Basin, Arctic Ocean; Canadian Beaufort Sea; Mackenzie River, N.W.T.


Winter variability of carbonate system parameters in the water column of Franklin Bay (Canadian Arctic, CASES winter station)   /   Lansard, B.   Mucci, A.   Miller, L.   Macdonald, R.W.   Gratton, Y.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 253
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67250.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

In the context of climate change, the time variability of carbonate system parameters in the Arctic Ocean remains an open question. During the Canadian Arctic Shelf Exchange Study (CASES), the research icebreaker Amundsen was ice-bound in Franklin Bay between 29th November 2003 and 1st June 2004 to study the winter variability of this arctic coastal zone. This presentation describes the temporal variability of carbonate system parameters (total alkalinity (TA), dissolved inorganic carbon (DIC) and pH) from this unique time-series of 33 vertical profiles recorded over the winter. CTD profiles revealed that the density stratification was mainly driven by the salinity and the presence of a stable mixed layer whose thickness (0-30 m depth) varies with the tidal cycle. The seawater temperature was close to the freezing point (-1.5°C) up to 150 m depth and increased to 0°C deeper. Total alkalinity ranged from 2215 to 2267 µmol/kg in the mixed layer while it was nearly constant at 2295 ±8 µmol/kg in the deep layer. Surface water pCO2 increased slightly from 350 ±20 µatm in December to 400 ±30 µatm in May. During the same period, the delta18O of seawater ranged from -4.1 to -2.2‰ in surface water and was close to 0.2‰ in the deep layers. The identification and distribution of water masses within the study area was accomplished using an optimum multi-parameter analysis (OMP) based on temperature, salinity, dissolved O2 concentrations, TA and delta18O. The analysis reveals a strong variability in the upper mixed layer probably due to (i) sea ice formation and brine rejection and (ii) changes in the water mass circulation. Below the upper halocline, a water mass with a 33.1 salinity, derived from the Pacific water, was found around 100 m depth. Below the deep thermocline, a water mass of Atlantic origin was always found in the bottom of the Franklin Bay. (Au)

D, G
Carbon; Chemical oceanography; Ocean currents; Ocean temperature; Oxygen-18; Salinity; Sea ice; Sea water; Seasonal variations; Water masses; Water pH

G0815, G11
Franklin Bay, N.W.T.; North Atlantic Ocean


Seasonal variability of water mass distribution in the southeastern Beaufort Sea determined by total alkalinity and delta 18O   /   Lansard, B.   Mucci, A.   Miller, L.A.   Macdonald, R.W.   Gratton, Y.
(Journal of geophysical research, v.117, C03003, 2012, 19 p., ill., maps)
References.
ASTIS record 76143.
Languages: English
Web: doi:10.1029/2011JC007299
Libraries: ACU

We examined the seasonal variability of water mass distributions in the southeastern Beaufort Sea from data collected between September 2003 and August 2004. Salinity, total alkalinity (TA) and isotopic composition (delta18O) of seawater were used together as tracers of freshwater input, i.e., meteoric water and sea ice meltwater. We used an optimum multiparameter analysis to identify the different water masses, including the Mackenzie River, sea ice melt (SIM), winter polar mixed layer (PML), upper halocline water (UHW) with core salinity of 33.1 psu (Pacific origin) and Atlantic Water. Computed values of CO2 fugacity in seawater (fCO-sw) show that the surface mixed layer (SML) remains mostly undersaturated (328 ± 55 µatm, n = 552) with respect to the average atmospheric CO2 concentration (380 ± 5 µatm) over the study period. The influence of the Mackenzie River (fCO2-sw> 500 µatm) was relatively small in the southeastern Beaufort Sea, and significant fractions were only observed on the inner Mackenzie Shelf. The contribution of sea ice melt (fCO2-sw < 300 µatm) to the SML could reach 30% beyond the shelf break and close to the ice pack in autumn. The density of the PML increased through the winter due to cooling and brine rejection. The winter PML reached a maximum depth of 70 m in late April. The UHW (fCO2-sw > 600 µatm) was usually located between 120 and 180 m depth, but could contribute to the SML during wind-driven upwelling events, in summer and autumn, and during brine-driven eddies, in winter. (Au)

D, E, G, F, H, I, J
Atmospheric temperature; Biological productivity; Carbon; Carbon cycling; Carbon dioxide; Carbonates; Chemical oceanography; Chlorophyll; Climate change; Environmental impacts; Fluorometry; Formation; Ice cover; Isotopes; Melting; Meteorology; Ocean temperature; Ocean-atmosphere interaction; Oceanography; Oxygen-18; Polynyas; Precipitation (Meteorology); River discharges; Rivers; Runoff; Salinity; Sea ice; Sea water; Seasonal variations; Spatial distribution; Temporal variations; Thickness; Water masses; Water pH; Weather stations; Winds

G07, G0815, G0812, G04, G11, G141, G05
Amundsen Gulf, N.W.T.; Arctic Ocean; Barents Sea; Bathurst, Cape, waters, N.W.T.; Bering Strait; Canada Basin, Arctic Ocean; Canadian Arctic Islands waters; Canadian Beaufort Sea; Chukchi Sea; Fram Strait; Franklin Bay, N.W.T.; Kugmallit Valley, Canadian Beaufort Sea; Mackenzie River, N.W.T.; Makarov Basin, Arctic Ocean; North Atlantic Ocean; North Pacific Ocean


Reconstitutions de la variabilité climatique dans l'axe principal du passage du Nord-Ouest au cours de l'Holocène   /   Ledu, D.   Rochon, A. [Supervisor]
Rimouski, Québec : Université du Québec à Rimouski, 2009.
xix, 205 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR65862)
ISBN 978-0-494-65862-8
Thesis (Ph.D.) - Université du Québec à Rimouski, Rimouski, Québec, 2009.
Appendices.
References.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
Contents: Introduction Générale - Chapitre 1: Palynological evidence of Holocene climate change in the eastern Arctic : a possible shift in the Arctic oscillation at the millennial time scale - Chapitre 2: Holocene paleoceanography of the Northwest Passage, Canadian Arctic Archipelago : the possible onset of an Arctic oscillation climate mode - Chapitre 3: Holocene sea-ice history and climate variability along the main axis of the Northwest Passage, Canadian Arctic.
ASTIS record 74744.
Languages: English or French
Web: http://semaphore.uqar.ca/302/
Libraries: QRU OONL

Des analyses palynologiques et géochimiques ont été réalisées sur trois carottes sédimentaires prélevées, dans les détroits de Lancaster, Barrow et Dease, le long de l'axe principal du passage du Nord-Ouest (APPNO). La chronologie des carottes sédimentaires est basée sur l'utilisation combinée d'âges radiocarbones et de corrélations magnétostratigraphiques. Les modèles d'âge indiquent que les carottes sédimentaires des détroits de Lancaster, Barrow et Dease couvrent respectivement les derniers 11,1, 10,8 et 7,7 ka calibrées BP. Les taux de sédimentation calcules sont compris entre 43 et 140 cm/ka pour le détroit de Lancaster et entre 15 et 118 cm/ka pour le détroit de Barrow. Un taux de sédimentation constant de 61 cm/ka caractérise le site du détroit de Dease. L'application de la technique des analogues modernes aux assemblages de kystes de dinoflagellés (dinokystes) a permis des estimations quantitatives des paramètres de surface (température, salinité et durée du couvert de glace) pour les trois séquences sédimentaires couvrant la quasi-totalité des 10 000 dernières années. L'Holocène ancien (entre ~11 et ~8,5 ka calibrées BP) est marque par des conditions instables avec d'importants apports terrigènes. Au détroit de Lancaster, cet intervalle se caractérise par une absence de dinokystes accompagnée d'importants apports terrigenes entre 11,1 et 10,8 ka calibrées BP suivie de conditions relativement froides comparées aux conditions modernes avec dominance des taxons hétérotrophes. Au détroit de Barrow, l'intervalle entre ~11 et ~8,5 ka calibrées BP est caractérise dans son ensemble par d'importants apports terrigènes avec des températures (aout) relativement froides comparées aux conditions modernes, et un couvert de glace fluctuant autour des valeurs modernes. De telles conditions, enregistrées aux détroits de Lancaster et de Barrow sont associées aux derniers stades de la déglaciation inuitienne dans la région. En particulier, la présence de courants de glace actifs jusqu'a environ 8,5 ka calibrées BP au niveau du bassin de Kane et du détroit de Smith pourrait avoir contribuée aux conditions froides enregistrées au détroit de Lancaster. La présence d'un courant de glace dans le chenal de Wellington accompagnée par un maximum d'épaisseur de glace dans le centre de l'archipel arctique canadien expliquent probablement l'importance des apports terrigènes pendant plus de 2000 ans au niveau du détroit de Barrow. La comparaison des reconstitutions quantitatives des paramètres de surface entre les trois sites a partir de ~8 ka calibrées BP jusqu'a l'Holocène récent a permis de mieux comprendre la nature et la variabilité du gradient climatique est-ouest caractéristique du réchauffement climatique actuel dans l'Arctique. Ce gradient, dont la présence a été documentée des le début de l'Holocène entre la baie de Baffin, la mer de Beaufort et de Chukchi, n'avait encore jamais été étudie le long de l'APPNO sur une base quantitative. Les résultats de cette recherche indiquent une variabilite climatique relativement importante à l'échelle millénaire le long de l'APPNO. L'Holocène moyen apparait comme une période de transition importante. Durant cet intervalle, les enregistrements du détroit de Dease suggèrent la mise en place du courant du Mackenzie dans sa configuration moderne. Des changements marques des conditions de surface sont également enregistres de manière synchronique au niveau des trois sites. Cette période de transition est associée à un changement de phase de l'oscillation arctique (OA+ vers OA-). La comparaison du delta 18O d'une carotte de glace prélevée sur I'île de Devon avec la température reconstitué (aout) du détroit de Lancaster suggère, en effet, un fort couplage atmosphère-océan durant la quasi-totalité de l'Holocène similaire aux effets de l'oscillation arctique. Cette dernière pourrait avoir opère a l'échelle millénaire depuis le début de l'Holocène. Cependant, les estimations quantitatives des conditions de surface pour les détroits de Lancaster et de Dease indiquent que la durée saisonnière du couvert de glace a été plus importante que les conditions modernes durant la quasi-totalité de l'Holocène. Ces résultats indiquent que le gradient climatique est-ouest est plus complexe qu'une simple opposition dipolaire entre le secteur oriental et occidental de l'archipel arctique canadien (AAC). Des facteurs locaux incluant que la proximité de glaciers, la présence de courants de cote ou la structure de l'halocline peuvent avoir amplifie, attenue ou renverse le signal climatique de mécanismes suprarégionaux tels que l'oscillation arctique. (Au)

B, E, G, D, H, J, A
Atmospheric circulation; Atmospheric temperature; Bottom sediments; Carbon; Climate change; Cores; Dinoflagellata; Effects of climate on ice; Geological time; Glacial deposits; Glacial epoch; Heterotrophic bacteria; Ice cover; Isotopes; Laurentide Ice Sheet; Nitrogen; Palaeobotany; Palaeoclimatology; Palaeoecology; Palaeohydrology; Palynology; Palynomorphs; Pleistocene epoch; Radiocarbon dating; Recent epoch; Sea ice; Seasonal variations; Sedimentation; Stratigraphy; Theses

G0815, G02
Arctic waters; Barrow Strait, Nunavut; Lancaster Sound, Nunavut; Northwest Passage


Mercury distribution in water and permafrost of the lower Mackenzie Basin, their contribution to the mercury contamination in the Beaufort Sea marine ecosystem, and potential effects of climate variation   /   Leitch, D.R.   Wang, F. [Supervisor]   Stern, G. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2006.
ix, 118 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR22546)
ISBN 978-0-494-22546-2
Appendices.
References.
Thesis (M.Sc.) - University of Manitoba, Winnipeg, Man., 2006.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74796.
Languages: English
Web: http://www.collectionscanada.gc.ca/obj/thesescanada/vol2/002/MR22546.PDF
Libraries: OONL

High levels of mercury (Hg) have recently been found in marine mammals in the Beaufort Sea, causing concerns over the health of the marine ecosystem and of indigenous people who consume marine mammals as part of their traditional diet. As part of a long-term research program aiming to probe the causes of such high Hg contamination, this thesis investigates the distribution and speciation of Hg in water of the lower Mackenzie River and in permafrost along the southern Beaufort Sea, their contribution as Hg sources to the Beaufort Sea, and their potential response to climate warming in the region. The Mackenzie River is the largest water and sediment source to the Beaufort Sea. Five sampling campaigns were carried out between 2003 and 2005 throughout the lower Mackenzie Basin. Large seasonal and annual variations of Hg were observed, with higher water levels resulting in higher Hg levels. This suggests additional Hg sources at high water levels. For the period of 2003-2005, the Mackenzie River discharged an average of 2.2 ±0.9 tonnes of Hg/year, of which approximately 15 kg was in the form of methylmercury (MeHg). The fact that approximately half of the annual Hg discharge occurs during the spring freshet is of concern to marine mammals, as this is the time of the year when marine mammals grow rapidly after a long winter, and hence would bioaccumulate more Hg in doing so. Higher fluxes of Hg and McHg are expected from the Mackenzie River with projected climate warming in the area. Rates of permafrost melt and coastal erosion along the southern Beaufort Sea coast are high, and likely to increase with climate change. Several permafrost cores were sampled along the Canadian portion of the Beaufort Sea coast showing two distinct types of profiles. Using published estimates of permafrost melt and coastal erosion, it was estimated that approximately 610 kg of Hg are degraded into the Beaufort Sea annually. As increases in temperature, open water season, storms, large waves, and sea level are predicted, it is very likely that permafrost degradation will increase. (Au)

F, B, D, I, J, E
Active layer; Atmospheric temperature; Bioaccumulation; Cesium; Climate change; Coast changes; Cores; Environmental impacts; Erosion; Forest fires; Lead; Marine ecology; Marine mammals; Marine pollution; Mercury; Ocean waves; Permafrost; River discharges; Rivers; Runoff; Sea level; Seasonal variations; Sediment transport; Snowmelt; Soil profiles; Spatial distribution; Storms; Stream flow; Suspended solids; Temporal variations; Thawing; Theses; Thickness; Water level; Water pollution; Watersheds

G07, G0812, G0811
Canadian Beaufort Sea; Herschel Island, Yukon; King Point region, Yukon; Komakuk Beach, Yukon; Mackenzie Delta, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River region, N.W.T.; Mackenzie River, N.W.T.; Tuktoyaktuk region, N.W.T.


The delivery of mercury to the Beaufort Sea of the Arctic Ocean by the Mackenzie River   /   Leitch, D.R.   Carrie, J.   Lean, D.   Macdonald, R.W.   Stern, G.A.   Wang, F.
(Science of the total environment, v.373, no. 1, 1 Feb. 2007, p. 178-195, ill., maps)
References.
ASTIS record 63286.
Languages: English
Web: doi:10.1016/j.scitotenv.2006.10.041
Libraries: ACU

Very high levels of mercury (Hg) have recently been reported in marine mammals and other higher trophic-level biota in the Mackenzie Delta and Beaufort Sea of the western Arctic Ocean. To quantify the input of Hg (particulate, dissolved and methylated) by the Mackenzie River as a potential source for Hg in the ecosystem, surface water and sediment samples were taken from 79 sites in the lower Mackenzie Basin during three consecutive summers (2003-2005) and analyzed for Hg and methylmercury (MeHg). Intensive studies were also carried out in the Mackenzie Delta during the freshets of 2004 and 2005. Large seasonal and annual variations were found in Hg concentrations in the river, coincident with the variations in water discharge. Increased discharges during spring freshet and during the summers of 2003 and 2005 compared to 2004 were mirrored by higher Hg concentrations. The correlation between Hg concentration and riverflow suggests additional Hg sources during periods of high water, potentially from increased surface inundation and increased bank erosion. The increase in the Hg concentration with increasing water discharge amplifies the annual Hg and MeHg fluxes during high water level years. For the period 2003-2005, the Hg and MeHg fluxes from the Mackenzie River to the Beaufort Sea averaged 2.2 tonnes/yr and 15 kg/yr, respectively, the largest known Hg source to the Beaufort Sea. More than half of the mercury flux occurs during the short spring freshet season which coincides with the period of rapid growth of marine biota. Consequently, the Mackenzie River input potentially provides the major mercury source to marine mammals of the Beaufort Sea. The Hg and MeHg fluxes from the Mackenzie River are expected to further increase with the projected climate warming in the Mackenzie Basin. (Au)

F, B, D, I, J, E
Atmospheric circulation; Bioaccumulation; Chemical oceanography; Climate change; Environmental impacts; Geochemistry; Marine ecology; Marine mammals; Mercury; River discharges; Rivers; Runoff; Seasonal variations; Stream flow; Suspended solids; Temporal variations; Toxicity; Water pollution; Watersheds; Zooplankton

G07, G0812, G03
Arctic Ocean; Canada Basin, Arctic Ocean; Canadian Beaufort Sea; Mackenzie Delta, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River region, N.W.T.; Mackenzie River, N.W.T.


Beaufort Sea storm and resuspension modeling   /   Lintern, D.G.   Macdonald, R.W.   Solomon, S.M.   Jakes, H.
(Northern coastal marine studies - the Nahidik program - environmental research of the coastal Canadian Beaufort Sea / Edited by Wojciech Walkusz and William J. Williams. Journal of marine systems, v.127, Nov. 2013, p. 14-25, ill., maps)
References.
ASTIS record 75452.
Languages: English
Web: doi:10.1016/j.jmarsys.2011.11.015
Libraries: ACU

Along the shallow Beaufort Sea coast of the Arctic Ocean, storm events during the summer are responsible for significant sediment resuspension and transport. Given the paucity of data in this difficult field area, a model has been developed to be used as a tool towards investigation of these processes. Two contrasting set of conditions are modeled; one simulation for a relatively quiescent period and a second simulation for a period that included a moderate and typical northwesterly storm. Results for these two periods are compared with shallow-water current and wave data collected by instrumented moorings. For the calm period, the model did not predict specific events very well, whereas for the period with a strong storm, the model performed very well in predicting wave height and wave period, and less well in predicting currents. However, under both calm and stormy conditions, mean current speeds and mean current directions were predicted with sufficient accuracy to proceed to calculations of sediment transport. Sensitivity analysis showed that currents contribute very little to the wave dominated resuspension, but mean currents could be used for computing sediment transport quantities and directions. Measurements of storm surge were represented well by the model output, aligning perfecting with the building and waning storm, but with a slight overprediction at the peak of the storm. The reasonable reproduction of wave heights and periods, and of storm surge indicate that the model is responding well to the input parameters. The modeling suggests that the most significant sediment erosion occurs at the northern tips of the Mackenzie Delta and the Tuktoyaktuk Peninsula, and around the area of Herschel Island. The model also indicates that waves are not fully developed during a storm for the present day ice limited fetch, and that extending the fetch a further 100 km to simulate ice retreat led to wave heights at the coast being increased by 20 cm. (Au)

D, E, G, A, F
Bathymetry; Coast changes; Density; Electronic data processing; Erosion; Floods; Ice cover; Mathematical models; Ocean currents; Ocean waves; River discharges; Sand; Sea ice; Sea level; Sediment transport; Silt; Size; Spatial distribution; Storm surges; Storms; Stress; Suspended solids; Tides; Velocity; Winds

G07, G0812
Bathurst, Cape, waters, N.W.T.; Herschel Island waters, Yukon; Herschel Island, Yukon; Kugmallit Bay region, N.W.T.; Liverpool Bay, N.W.T.; Mackenzie Bay, N.W.T./Yukon; Mackenzie Delta, N.W.T.; Mackenzie River, N.W.T.; North Head (69 43 N, 134 26 W) waters, N.W.T.; Shallow Bay, N.W.T.; Tuktoyaktuk Peninsula waters, N.W.T.; Tuktoyaktuk Peninsula, N.W.T.


Corrections for beam pattern residuals in backscatter imagery from the Kongsberg-Simrad EM300 multibeam echosounder   /   Llewellyn, K.C.   Hughes Clarke, J.E. [Supervisor]
Fredericton, N.B. : University of New Brunswick, 2006.
[104] p. : ill., maps ; 28 cm.
Appendices.
References.
Thesis (M.Eng.) - University of New Brunswick, Fredericton, N.B., 2006.
A report submitted in partial fulfillment of degree requirements.
Indexed from a PDF file available online.
PDF file does not have page numbers.
ASTIS record 63294.
Languages: English
Web: http://www.omg.unb.ca/omg/papers/Kristian_MEng_Final.pdf

This report outlines the research and subsequent software development to correct for beam pattern residuals in backscatter mosaics derived from the Kongsberg-Simrad EM300 multibeam system installed on the Canadian Coast Guard Ship Amundsen. Since 2003, the UNB Ocean Mapping Group (OMG) has been tasked with the acquisition, processing, management, and distribution of all hydrographic data from the ship as part of the Canadian Arctic Shelf Exchange Study and ArticNet projects organized and financed through the Natural Sciences and Engineering Research Council of Canada and the Canadian Foundation for Innovation. In addition to the typical bathymetric products available from multibeam sonar systems, backscatter mosaics are also needed to support other scientific objectives on board the vessel, particularly ongoing paleo-oceanographic research. This involves boxcore and piston-core samples taken from the surface and sub-surface of the seabed in the high Canadian arctic. Having accurate seafloor backscatter information is vital to choosing appropriate locations for these activities. It is therefore crucial to provide such backscatter products with all apparent changes in such products due to actual changes in seafloor geology and not due to beam pattern fluctuations from the sonar system. There is a great deal of calibration performed automatically by the Simrad system on raw backscatter data, and OMG beam correction software exists to further calibrate backscatter in several different ways. Even so, residual beam pattern effects still exist in the resulting mosaics from the Amundsen due to additional complications with the EM300. This report describes the ship and the ArcticNet program in general, discusses the technical details of the EM300 sonar system, and reviews some general and Simradspecific backscatter theory as well as current OMG beam pattern correction practices. Finally, it describes further research and software development created for this project to correct for residual beam pattern effects in the Amundsen EM300 data. (Au)

D, A, L
Amundsen (Ship); Bathymetry; Electronic data processing; Icebreakers; Instruments; Logistics; Mapping; Measurement; Oceanography; Remote sensing; Sonar; Submarine topography; Theses

G081
Canadian Arctic waters; Northwest Passage


Beaufort beluga movement and diet related mercury levels   /   Loseto, L.L.   Stern, G.A.   Richard, P.   Connelly, T.   Gemmill, B.   Ferguson, S.H.
In: ArcticNet programme 2005 : annual scientific meeting, 13-16/12/2005, Banff, Alberta = ArcticNet programme 2005 : réunion scientifique annuelle, 13-16/12/2005, Banff, Alberta. - [Québec, Québec] : ArcticNet, 2005, p. 24-25
Abstract only.
Indexed a PDF file from the Web.
ASTIS record 65222.
Languages: English
Web: http://www.arcticnet.ulaval.ca/pdf/Programme_ASM2005.pdf

Beaufort Beluga whales have some of the highest mercury (Hg) levels among Canadian beluga whale populations. Ultimately it is the prey that Beluga feed on that determine Hg levels; however, little is known about Beaufort Beluga habitat use, migration patterns, foraging behaviour, and diet. Here we evaluate foraging behaviour and try to determine diet to calculate Hg trophic level transfer. Two approaches are used to characterize beluga diet; i) a spatiotemporal approach to determine feeding regions and migratory paths using satellite telemetry, and ii) a biochemical approach to quantify seasonal diet by comparing stable isotopes and fatty acid signatures in beluga tissues with potential prey items; together this will provide the geographical and trophic related sources of Hg uptake. For the first time an annual summary of Beaufort beluga satellite positions collected (2004-2005). Based on seasonal movement, prey items were collected from the summering grounds (Mackenzie Delta/Beaufort Sea) and wintering grounds (Bering Sea). In the summering grounds stable isotopes delta 15N and delta 13C and fatty acids were measured in biota including estuary fish species such as Pacific Herring, Arctic Cisco (Clupea pallasii, Coregonus autumnalis), the marine fish species Arctic Cod (Boreogadus saida), epibenthic fish (Myoxocephalus octodecemspinosus, Platichthys stellatus, Pleuronectes glacialis) and epibenthic invertebrate such as decapods (Eualus gaimardii) and amphipods (Anonyx spp). Trophic levels were determined and used to calculate food web magnification factors (FWMFs) and biomagnification factors (BMFs) of Hg to beluga from various prey type (benthic, estuary, pelagic) in summering grounds and will be compared with results for the wintering region. Arctic Cod Hg levels (chi=0.43 µg/g dw; sigma=0.2), were higher than in most estuary species (<0.3 µg/g dw), which was supported by a higher trophic position, however epibenthic species had the highest Hg levels measured (range 0.5 to 0.68 µg/g dw). Preliminary results from fatty acid analysis show Beluga signatures are similar to Arctic Cod and some estuary species, and show less resemblance to benthic invertebrates. Understanding beluga foraging behaviour, diet, and Hg sources will assist in conservation efforts in a region undergoing considerable economic development and climate warming. (Au)

I, J, L
Animal behaviour; Animal distribution; Animal food; Animal migration; Arctic cod; Beluga whales; Biological sampling; Biomagnification; Carbon; Fatty acids; Fishes; Food chain; Invertebrates; Isotopes; Marine pollution; Mercury; Nitrogen; Predation; Radio tracking of animals; Satellite communications; Seasonal variations; Spatial distribution; Trophic levels; Wildlife habitat

G07, G04
Bering Sea; Canadian Beaufort Sea; Mackenzie Estuary, N.W.T./Yukon


Segregation of Beaufort Sea beluga whales during the open-water season   /   Loseto, L.L.   Richard, P.   Stern, R.G.   Orr, J.   Ferguson, S.H.
(Canadian journal of zoology, v. 84, no. 12, Dec. 2006, p.1743-1751, ill., 1 map)
References.
ASTIS record 62439.
Languages: English
Web: doi:10.1139/Z06-160
Libraries: ACU

Population segregation by habitat use occurs because energy requirements and survival strategies vary with age, sex, size, and reproductive stage. From late summer to early fall in 1993, 1995, and 1997, relative length (age), sex, and reproductive status of satellite-tagged beluga whales (Delphinapterus leucas (Pallas, 1776)) in the eastern Beaufort Sea were tested for habitat segregation. We used (i) resource selection function models to evaluate how belugas used areas of varying sea ice concentration and shelf habitat and (ii) distance analysis to measure the selection of areas varying in distance to mainland and island coastlines. Resource selection functions and distance analysis established that habitat selection differed with length, sex, and reproductive status of whales: (i) females with calves and smaller males selected open-water habitats near the mainland; (ii) large males selected closed sea ice cover in and near the Arctic Archipelago; and (iii) smaller males and two females with calves (not newborn) selected habitat near the ice edge. The segregation of habitat use according to sex, age, and reproductive status relates to the different resources required at different life stages and may represent characteristics of beluga social structure. We discuss our results in the context of two common sexual segregation hypotheses and conclude that summer habitat segregation of belugas reflects differences in foraging ecology, risk of predation, and reproduction. (Au)

I, J, G
Age; Animal behaviour; Animal distribution; Animal food; Animal population; Animal reproduction; Animal tagging; Beluga whales; Estuarine ecology; Gender differences; Marine ecology; Mathematical models; Predation; Radio tracking of animals; Satellite communications; Sea ice; Sea ice ecology; Seasonal variations; Telemetry; Temporal variations; Wildlife habitat

G07
Mackenzie Estuary, N.W.T./Yukon


Beaufort Sea beluga whales : an ecological approach to examining diet and dietary sources of mercury   /   Loseto, L.L.   Ferguson, S.H. [Supervisor]   Stern, G.A. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2007.
x, 144 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR36269)
ISBN 978-0-494-36269-3
References.
Thesis (Ph.D.) - University of Manitoba, Winnipeg, Man., 2007.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 65068.
Languages: English
Libraries: OONL

Mercury (Hg) levels in the Beaufort Sea beluga (Delphinapterus leucas) population have been increasing since the 1990s. Ultimately, it is the Hg content of prey that determines beluga Hg levels. However, the Beaufort Sea beluga diet is not understood, and little is known about the food webs and Hg sources in their summer habitat. Using satellite telemetry data, the Beaufort Sea Beluga were found to segregate into habitat use groups, by length, sex and reproductive status. Segregation of habitat use lead to the hypothesis that beluga may feed differently, explaining Hg dietary sources. Mercury levels were measured in three food webs in the western Canadian Arctic to assess their dietary Hg contribution. Results revealed that potential beluga prey had variable Hg concentrations. With the use of the diet biomarkers stable isotopes and fatty acids in both prey items and beluga, the beluga diet was evaluated by incorporating beluga biological variables such as age, length, sex and harvest location. Here, we show the factors driving beluga diet variability lead to differences in dietary Hg uptake. Diet variability within the Beaufort Sea beluga was evident, whereby larger beluga appeared to feed predominantly on offshore arctic cod (Boreogadus saida), and medium and smaller sized beluga incorporated more near-shore fish collected from the Mackenzie shelf. The variation in beluga diet was supported by the differences in Hg concentrations and delta 15 N values in both prey and beluga. For the first time, we demonstrate that food web Hg biomagnification processes drive beluga muscle Hg levels, rather than Hg bioaccumulation over time. This conclusion revealed that dietary Hg levels varied with habitat use, where the shelf was low source of Hg and the offshore was a high source. Therefore, incorporating beluga habitat use along with food web complexity was important in determining the factors driving beluga Hg levels. These observations lend support to the possibility that the high levels of Hg leaving the Mackenzie River only become bioavailable for food web uptake once entering offshore habitats. (Au)

I, J
Age; Animal behaviour; Animal distribution; Animal ecology; Animal food; Arctic cod; Beluga whales; Benthos; Bioaccumulation; Biological sampling; Biomagnification; Carbon; Chromatography; Dentition; Fats; Fatty acids; Fishes; Food chain; Gender differences; Internal organs; Invertebrates; Isotopes; Marine ecology; Marine pollution; Mass spectrometry; Mercury; Metabolism; Nitrogen; Predation; Radio tracking of animals; Satellites; Size; Spectroscopy; Telemetry; Theses; Toxicity; Trophic levels; Wildlife habitat; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Browns Harbour, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Kugmallit Bay, N.W.T.; M'Clure Strait, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Viscount Melville Sound, N.W.T./Nunavut


Linking mercury exposure to habitat and feeding behaviour in Beaufort Sea beluga whales   /   Loseto, L.L.   Stern, G.A.   Deibel, D.   Connelly, T.L.   Prokopowicz, A.   Lean, D.R.S.   Fortier, L.   Ferguson, S.H.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió . Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p.1012-1024, ill., maps)
References.
ASTIS record 65066.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.10.004
Libraries: ACU

Mercury (Hg) levels in the Beaufort Sea beluga population have been increasing since the 1990s. Ultimately, it is the Hg content of prey that determines beluga Hg levels. However, the Beaufort Sea beluga diet is not understood, and little is known about the diet Hg sources in their summer habitat. During the summer, they segregate into social groups based on habitat use leading to the hypothesis that they may feed in different food webs explaining Hg dietary sources. Methyl mercury (MeHg) and total mercury (THg) levels were measured in the estuarine-shelf, Amundsen Gulf and epibenthic food webs in the western Canadian Arctic collected during the Canadian Arctic Shelf Exchange Study (CASES) to assess their dietary Hg contribution. To our knowledge, this is the first study to report MeHg levels in estuarine fish and epibenthic invertebrates from the Arctic Ocean. Although the Mackenzie River is a large source of Hg, the estuarine-shelf prey items had the lowest MeHg levels, ranging from 0.1 to 0.27 µg/g dry weight (dw) in arctic cisco (Coregonus autumnalis) and saffron cod (Eleginus gracilis) respectively. Highest MeHg levels occurred in fourhorn sculpin (Myoxocephalus quadricornis) (0.5 µg/g dw) from the epibenthic food web. Beluga hypothesized to feed in the epibenthic and Amundsen Gulf food webs had the highest Hg levels matching with high Hg levels in associated food webs, and estuarine-shelf belugas had the lowest Hg levels (2.6 µg/g dw), corresponding with the low food web Hg levels, supporting the variation in dietary Hg uptake. The trophic level transfer of Hg was similar among the food webs, highlighting the importance of Hg sources at the bottom of the food web as well as food web length. We propose that future biomagnification studies incorporate predator behaviour with food web structure to assist in the evaluation of dietary Hg sources. (Au)

I, J
Age; Amphipoda; Animal behaviour; Animal distribution; Animal ecology; Animal food; Arctic cisco; Arctic cod; Beluga whales; Benthos; Biological sampling; Biomagnification; Carbon; Chromatography; Copepoda; Dentition; Estuarine ecology; Fishes; Food chain; Fourhorn sculpin; Gender differences; Invertebrates; Isotopes; Marine ecology; Mass spectrometry; Mercury; Mysidacea; Nitrogen; Predation; Saffron cod; Size; Spectroscopy; Trophic levels; Wildlife habitat; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon


Summer diet of beluga whales inferred by fatty acid analysis of the eastern Beaufort Sea food web   /   Loseto, L.L.   Stern, G.A.   Connelly, T.L.   Deibel, D.   Gemmill, B.   Prokopowicz, A.   Fortier, L.   Ferguson, S.H.
(Journal of experimental marine biology and ecology, v.374, no. 1, 15 June 2009, p. 12-18, ill., maps)
References.
ASTIS record 68199.
Languages: English
Web: doi:10.1016/j.jembe.2009.03.015
Libraries: ACU

Beluga whales (Delphinapterus leucas) are the most abundant odontocetes in Arctic waters and are thus thought to influence food web structure and function. The diet of the Beaufort Sea beluga population is not well known, partly due to the inherent difficulty of observing feeding behaviour in Arctic marine cetaceans. To determine which prey items are critical to the Beaufort Sea beluga diet we first examine and describe the Mackenzie Delta and Beaufort Sea food web using fatty acid analyses. Fatty acid profiles effectively partitioned prey items into groups associated with their habitat and feeding ecology. Next, the relative contribution of various prey items to beluga diet was investigated using fatty acids. Finally, beluga diet variability was examined as a function of body size, a known correlate of habitat use. Beluga appeared to feed predominantly on Arctic cod (Boreogadus saida) collected from near shore and offshore regions. Size related dietary differences suggested larger sized beluga preferred offshore Arctic cod given the shared high levels of long chain monounsaturates, whereas smaller sized beluga appeared to feed on prey in their near shore habitats that included near shore Arctic cod. The presence of Arctic cod groups in shallow near shore and deep offshore habitats may facilitate the behavioural segregation of beluga habitat use as it relates to their size and resource requirements. Given Arctic cod are a sea ice associated fish combined with the accelerated sea ice loss in this region, beluga whales may need to adapt to new dietary regimes. (Au)

I, J
Amphipoda; Animal behaviour; Animal distribution; Animal food; Arctic cod; Beluga whales; Benthos; Biological sampling; Chromatography; Fats; Fatty acids; Fishes; Food chain; Invertebrates; Mass spectrometry; Mysidacea; Predation; Shrimp; Size; Trophic levels; Wildlife habitat

G07, G0815
Amundsen Gulf, N.W.T.; Browns Harbour, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Tuktoyaktuk waters, N.W.T.


Diversity and distribution of marine microbial eukaryotes in the Arctic Ocean and adjacent seas   /   Lovejoy, C.   Massana, R.   Pedrós-Alió, C.
(Applied and environmental microbiology, v. 72, no. 5, May 2006, p.3085-3095, ill., 1 map)
References.
ASTIS record 60650.
Languages: English
Web: doi:10.1128/AEM.72.5.3085-3095.2006
Libraries: ACU

We analyzed microbial eukaryote diversity in perennially cold arctic marine waters by using 18S rRNA gene clone libraries. Samples were collected during concurrent oceanographic missions to opposite sides of the Arctic Ocean Basin and encompassed five distinct water masses. Two deep water Arctic Ocean sites and the convergence of the Greenland, Norwegian, and Barents Seas were sampled from 28 August to 2 September 2002. An additional sample was obtained from the Beaufort Sea (Canada) in early October 2002. The ribotypes were diverse, with different communities among sites and between the upper mixed layer and just below the halocline. Eukaryotes from the remote Canada Basin contained new phylotypes belonging to the radiolarian orders Acantharea, Polycystinea, and Taxopodida. A novel group within the photosynthetic stramenopiles was also identified. One sample closest to the interior of the Canada Basin yielded only four major taxa, and all but two of the sequences recovered belonged to the polar diatom Fragilariopsis and a radiolarian. Overall, 42% of the sequences were <98% similar to any sequences in GenBank. Moreover, 15% of these were <95% similar to previously recovered sequences, which is indicative of endemic or undersampled taxa in the North Polar environment. The cold, stable Arctic Ocean is a threatened environment, and climate change could result in significant loss of global microbial biodiversity. (Au)

I, H, D, E, J
Algae; Animal distribution; Animal taxonomy; Bacteria; Biological sampling; Carbon cycling; Climate change; Cold adaptation; Diatoms; Food chain; Genetics; Marine ecology; Microbial ecology; Microorganisms; Ocean temperature; Plant taxonomy; Radiolaria; Salinity; Sea ice; Seasonal variations; Solar radiation; Water masses

G03, G07
Arctic Ocean; Canadian Beaufort Sea


Distribution, phylogeny, and growth of cold-adapted picoprasinophytes in Arctic seas   /   Lovejoy, C.   Vincent, W.F.   Bonilla, S.   Roy, S.   Martineau, M.-J.   Terrado, R.   Potvin, M.   Massana, R.   Pedrós-Alió, C.
(Journal of phycology, v. 43, no. 1, Feb. 2007, p. 78-89, ill., map)
References.
ASTIS record 63271.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/210.pdf
Web: doi:10.1111/j.1529-8817.2006.00310.x
Libraries: ACU

Our pigment analyses from a year-long study in the coastal Beaufort Sea in the western Canadian Arctic showed the continuous prevalence of eukaryotic picoplankton in the green algal class Prasinophyceae. Microscopic analyses revealed that the most abundant photosynthetic cell types were Micromonas-like picoprasinophytes that persisted throughout winter darkness and then maintained steady exponential growth from late winter to early summer. A Micromonas (CCMP2099) isolated from an Arctic polynya (North Water Polynya between Ellesmere Island and Greenland), an ice-free section, grew optimally at 6°C-8°C, with light saturation at or below 10 µmol photons/m²/s at 0°C. The 18S rDNA analyses of this isolate and environmental DNA clone libraries from diverse sites across the Arctic Basin indicate that this single psychrophilic Micromonas ecotype has a pan-Arctic distribution. The 18S rDNA from two other picoprasinophyte genera was also found in our pan-Arctic clone libraries: Bathycoccus and Mantoniella. The Arctic Micromonas differed from genotypes elsewhere in the World Ocean, implying that the Arctic Basin is a marine microbial province containing endemic species, consistent with the biogeography of its macroorganisms. The prevalence of obligate low-temperature, shade-adapted species in the phytoplankton indicates that the lower food web of the Arctic Ocean is vulnerable to ongoing climate change in the region. (Au)

H, D, J, E
Algae; Biological sampling; Chlorophyll; Chromatography; Climate change; Cold adaptation; Cyanophyceae; Fluorometry; Food chain; Genetics; Light; Marine ecology; Measurement; Microbial ecology; Microorganisms; Ocean temperature; Plant distribution; Plant growth; Plant taxonomy; Salinity; Seasonal variations; Spectroscopy; Water masses

G07, G09, G0815, G03, G12, G141
Barents Sea; Canadian Beaufort Sea; Dease Strait, Nunavut; Franklin Bay, N.W.T.; Greenland Sea; North Water Polynya, Baffin Bay; Northwind Ridge, Arctic Ocean


On sea ice concentration anomaly coherence in the southern Beaufort Sea   /   Lukovich, J.V.   Barber, D.G.
(Geophysical research letters, v. 32, no. 10, L10705, May 2005, 4 p., ill., maps)
References.
ASTIS record 63273.
Languages: English
Web: doi:10.1029/2005GL022737
Libraries: ACU

The circumpolar flaw lead polynya system is a region of enhanced biological productivity and for significant portions of the annual cycle, dominates the exchange of energy and mass across the ocean-sea ice-atmosphere (OSA) interface. We investigate the nature of sea ice concentration (SIC) anomalies for spatial and temporal statistical persistence within a portion of this flaw lead system. We find such a structure in the shelf break zone between Amundsen Gulf and the Canada Basin. NCEP/NCAR reanalysis data is used to determine the potential roles of oceanic and atmospheric forcing in creating and maintaining this observed coherence in the SIC anomalies. Results suggest that the coherence pattern is consistent over the instrumental record (1979 to 2000), although it changes in shape and extent between years. The forcing mechanisms creating this coherence in SIC anomalies appear to be tied to surface wind-driven upwelling in the shelf-break areas of the Southern Beaufort Sea (SBS). (Au)

G, D, E
Atmospheric pressure; Atmospheric temperature; Climate change; Continental shelves; Effects of climate on ice; Environmental impacts; Fast ice; Ice cover; Ice leads; Ocean currents; Ocean-atmosphere interaction; Pack ice; Polynyas; Sea ice; Spatial distribution; Temporal variations; Water masses; Winds

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea


Atmospheric controls on sea ice motion in the southern Beaufort Sea   /   Lukovich, J.V.   Barber, D.G.
(Journal of geophysical research, v.111, no. 18, D18103, Sept. 2006, 12 p., ill., maps)
References.
ASTIS record 62068.
Languages: English
Web: doi:10.1029/2005JD006408
Libraries: ACU

The Beaufort sea ice gyre is characterized in winter months by an anticyclonic regime associated with sea level pressure (SLP) highs. Previous studies have shown instances of a reversal in this regime in summer months with the arrival of SLP lows over the Beaufort Sea, while also demonstrating a link to variations in lower stratospheric potential vorticity. In this study we examine the role of relative vorticity in describing dynamic variability on weekly timescales from the surface to the middle stratosphere. Results from this analysis show that the Beaufort Gyre is characterized predominantly by anticyclonic activity throughout the year for the time interval considered (from 1979 to 2000), with a summer reversal to cyclonic activity, whose strength and duration varies between years. These reversals coincide with reversals in SLP based on a correlation analysis. Comparison of ice and atmospheric relative vorticity fields in the Beaufort Sea region (BSR) for all weeks from 1979 to 2000 indicates that sea ice and lower tropospheric processes are anticorrelated at zero time lag. This is in contrast to relative vorticity fields at 10 mbar, which exhibit maximum correlation between stratospheric and sea ice responses when 10 mbar leads ice relative vorticity by 2-6 weeks. (Au)

G, D, E
Atmospheric pressure; Movement; Ocean currents; Ocean-atmosphere interaction; Sea ice; Seasonal variations; Stratosphere; Temporal variations; Velocity; Winds

G07
Alaskan Beaufort Sea; Canadian Beaufort Sea


On the spatiotemporal behavior of sea ice concentration anomalies in the Northern Hemisphere   /   Lukovich, J.V.   Barber, D.G.
(Journal of geophysical research, v.112, no. 13, D13117, July 2007, 12 p., ill., maps)
References.
ASTIS record 74144.
Languages: English
Web: doi:10.1029/2006JD007836
Libraries: ACU

Reduction in the aerial extent and thickness of sea ice in the Northern Hemisphere is an important element in understanding how the arctic responds to global-scale climate variability and change. Previous studies have demonstrated a significant reduction in minimum sea ice extent [Serreze et al., 2003] with record reduction in 2005. Observational studies attribute this phenomenon to variations in sea level pressure and large-scale atmospheric teleconnection patterns such as the Northern Annular Mode (NAM) [Deser et al., 2000; Serreze et al., 2003]. In this study we examine variations in sea ice in the context of spatiotemporal variability of sea ice concentration (SIC) anomalies in the Northern Hemisphere during the onset of ice formation. Examined in particular are timescales associated with coherent regions of persistence in an e-folding time spatial distribution (EFSD). Annual variations of weekly SIC anomalies are studied and spatial relations between positive and negative SIC anomalies are explored on a hemispheric scale. The results from this investigation demonstrate coherent SIC persistence patterns throughout the Northern Hemisphere, with timescales ranging from 3 to 7 weeks. Spatial correspondence between negative trends in SIC anomalies and the EFSD suggests that the same mechanism may be responsible for both increased ice reduction and persistence in this region. Examination of spatial coherence in SIC anomalies indicates that maximum SIC anomalies prevail near the Kara Sea, Beaufort Sea, and Chukchi Sea regions during late summer/early fall from 1979 to 2004. A latitudinal assessment at 80°, 70°, and 60°N indicates a poleward shift and retreat in SIC anomalies, while also underlining the decadal shift in variability often attributed to the NAM. (Au)

G, D, E, A
Albedo; Atmospheric circulation; Atmospheric pressure; Continental shelves; Formation; Ice cover; Mapping; Maps; Movement; Ocean currents; Ocean-atmosphere interaction; Satellites; Sea ice; Seasonal variations; Spatial distribution; Special Sensor Microwave/Imager ; Temporal variations; Thickness; Winds

G02, G081
Arctic waters; Arctic waters; Canadian Arctic ; Canadian Arctic waters


The Mackenzie Estuary of the Arctic Ocean   /   Macdonald, R.W.   Yu, Y.
In: The handbook of environmental chemistry, v. 5, part H, water pollution, estuaries / Edited by P.J. Wangersky. - Berlin ; Heidelberg, Germany : Spinger-Verlag, 2006, p. 91-120, ill., maps
References.
ASTIS record 63346.
Languages: English
Libraries: AEU

The Mackenzie Estuary is a seasonally ice covered, deltaic estuary. It receives over 300 km³ of freshwater and 125 × 10**6 t of sediment annually in a strongly modulated seasonal cycle. Ice cover plays a crucial role in the physical setting by limiting air-sea interaction (energy and gas exchange), reducing mixing, and withdrawing freshwater from the estuary while leaving behind the bulk of the dissolved components. Few studies have been conducted on estuarine processes occurring in this estuary and, although we can project from temperate estuaries what the important conservative and nonconservative processes are likely to be, the winter encroachment by ice sufficiently alters the physical, chemical, and biological processes that projections from other estuaries will likely be wrong. Here we discuss how the estuary evolves through the seasonal cycles of temperature, ice cover, river inflow, particle loadings, and winds, and review what is known of the biogeochemical cycling within the estuary. Given that the Arctic is exceptionally vulnerable to change, especially in the marginal seas, it is safe to predict that remote, pristine estuaries of the Arctic are as much at risk in the future as estuaries more directly impacted by human encroachment. (Au)

D, F, G, B, E, H
Algae; Atmospheric temperature; Bathymetry; Bottom sediments; Breakup; Carbon; Climate change; Coast changes; Density; Environmental impacts; Erosion; Estuaries; Fast ice; Formation; Growth; Heat transmission; Ice cover; Ice leads; Melting; Nitrogen; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Phosphorus; Phytoplankton; Polynyas; Primary production (Biology); River deltas; River discharges; River ice; Runoff; Salinity; Seasonal variations; Sediment transport; Silicates; Solar radiation; Spatial distribution; Stamukhi; Storm surges; Storms; Stream flow; Suspended solids; Temporal variations; Thermal regimes; Thickness; Tides; Water masses; Winds

G0812, G0811, G07
Canadian Beaufort Sea; Mackenzie Delta, N.W.T.; Mackenzie Delta, Yukon; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.


Glacial flute marks and iceberg scours inscribed on the seabed in Peel Sound, Franklin Strait, Larsen Sound and M'Clintock Channel, Canadian Arctic Archipelago   /   MacLean, B.   Blasco, S.   Bennett, R.   Rainey, W.   Hughes-Clarke, J.   Beaudoin, J.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 263-264
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67270.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

The study area lies within the central part of the Canadian Arctic Archipelago; a region that was covered by Laurentide ice during the Late Wisconsinan and earlier. Multibeam imagery from widely spaced transects indicates the presence of both parallel - sub-parallel ice keel features and randomly oriented iceberg scours on the seabed at localities in Peel Sound, Franklin Strait, northern Larsen Sound, and in M'Clintock Channel. Linear parallel - sub-parallel groove and ridge features are interpreted to be sole marks emplaced on the seabed by ice streams that formerly occupied these marine areas. These features have been observed on multibeam imagery at various localities along the channels, and are especially well developed in an overdeepened area at the junction of Franklin Strait and Peel Sound. The trend of these features is parallel to the axes and coastlines of the channels. Their north-south orientation in Peel Sound is normal to that of glacial ice flow features on Somerset and eastern Prince of Wales islands, which border Peel Sound to the east and west, respectively. The seabed in many areas also displays scours formed by grounding icebergs. These are primarily single keel features. Maximum iceberg grounding depths are variable relative to present day water depths. Ice stream sole mark features in water depths deeper than 350 m in the overdeepened area in Peel Sound have not been impacted by grounding icebergs. Above 350 m, iceberg scours of variable orientations increase in number and decrease in size as depths shallow. However, in the southern M'Clintock Channel - Larsen Sound area, apparently unmodified parallel - sub-parallel ice keel features occur in depths as shallow as 145 m. Seabed sediments revealed by 3.5 kHz sub-bottom profiles are interpreted to consist primarily of ice-contact deposits that in a few localities are draped by later sediments. The age of the ice stream features has not been established. Their formation was possibly coincident with an ice stream in the M'Clintock Channel - Victoria Island region, which formed an ice shelf in Viscount Melville Sound that grounded on southern Melville and Byam Martin islands at ca. 10.4 - 9.6 ka. Or they could have resulted from later glacial events. The iceberg scours observed on the multibeam imagery are inferred to be mainly relict features. (Au)

A, G, F, B
Bottom sediments; Flow; Glacial epoch; Glacial landforms; Ice scouring; Ice shelves; Icebergs; Laurentide Ice Sheet; Ocean floors; Pressure ridges; Remote sensing; Sediments (Geology); Spatial distribution; Submarine topography

G0815
Franklin Strait, Nunavut; Larsen Sound, Nunavut; M'Clintock Channel, Nunavut; Peel Sound, Nunavut


Origin, sedimentation and diagenesis of organic matter in coastal sediments of the southern Beaufort Sea region, Canadian Arctic   /   Magen, C.   Sundby, B. [Supervisor]   Mucci, A. [Supervisor]
Montreal : McGill University, c2007.
x, 130 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR53292)
ISBN 9780494532928
Thesis (Ph.D.) - McGill University, Montreal, Quebec, 2007.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
References.
ASTIS record 74976.
Languages: English
Libraries: OONL

The source and fate of organic carbon in coastal sediments of the Beaufort Sea, Canadian Arctic, are examined. Despite the Mackenzie River's discharge to the coastal waters, sediments of the adjacent slope and Amundsen Gulf have a similar organic carbon content and C ORG :N ratio to sediments of the continental margin. In contrast, the stable isotope composition of the organic carbon and nitrogen reveal striking differences: low delta 13 C and delta 15 N values are found in Beaufort Shelf sediments indicative of a terrigenous origin, whereas higher values, closer to the marine signature, are observed in the Amundsen Gulf sediments. On the Slope, the isotopic signatures are intermediate and may be interpreted as a mixture of terrigenous and marine organic matter. These results indicate that the terrigenous suspended matter carried by the Mackenzie River's plume and discharged to the Beaufort Sea does not spread to the Amundsen Gulf. Organic carbon that settles onto the seafloor fuels most early diagenetic reactions. The nature and amount that reaches the sediment determines the vertical zonation of redox reactions within the sediment. In turn, the vertical distribution of available oxidants can be used to infer the flux of organic carbon to the seafloor. The Mn and Fe oxide content of Gulf and Slope sediments are one order of magnitude larger than in Shelf sediments, indicating that the Mn and Fe cycles are maintained well below the sediment-water interface by low accumulation rates of organic carbon. Conversely, in margin sediments, high organic carbon accumulation rates bring the Mn and Fe cycles closer to the interface and allow their escape to the overlying waters. In strongly seasonal environments, organic carbon is typically delivered to the sediment in pulses. To simulate the influence of episodic organic carbon fluxes on the sediment chemistry, closed jar incubation experiments were conducted using both Mn and Fe oxide-poor (Mackenzie Shelf) and -rich sediments (Amundsen Gulf). Experimental Mn reduction rates were fit reasonably well to a rate law that is first order with respect to both organic carbon and Mn oxide concentrations. The Fe reduction rates were also proportional to the organic matter concentration. These results indicate that a sudden incorporation of fresh organic matter to the sediment can deplete the sedimentary pool of Mn and Fe oxide within a few days. (Au)

B, F, D, J, A, G, E, H
Algae; Bacteria; Biological productivity; Bottom sediments; Carbon; Carbon cycling; Chemical properties; Climate change; Continental shelves; Cores; Estuaries; Geochemistry; Hydrological stations; Interstitial water; Iron; Isotopes; Manganese; Measurement; Nitrogen; Physical properties; Plankton; Primary production (Biology); River discharges; Rivers; Sea ice; Seasonal variations; Sediment transport; Sedimentation; Suspended solids; Temporal variations; Theses

G0815, G07, G0812, G04
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Chukchi Sea; Kugmallit Valley, Canadian Beaufort Sea; Mackenzie Delta, N.W.T.; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Origin and fate of particulate organic matter in the southern Beaufort Sea - Amundsen Gulf region, Canadian Arctic   /   Magen, C.   Chaillou, G.   Crowe, S.A.   Mucci, A.   Sundby, B.   Gao, A.   Makabe, R.   Sasaki, H.
(Estuarine, coastal and shelf science, v. 86, no. 1, 1 Jan. 2010, p. 31-41, ill., maps)
References.
ASTIS record 71842.
Languages: English
Web: doi:10.1016/j.ecss.2009.09.009
Libraries: ACU

To establish the relative importance of terrigenous and marine organic matter in the southern Beaufort Sea, we measured the concentrations and the stable isotopic compositions of organic carbon and total nitrogen in sediments and in settling particles intercepted by sediment traps. The organic carbon content of surface sediment in the Chukchi and southern Beaufort Seas ranged from 0.6 to 1.6% dry wt., without a clear geographical pattern. The CORG:NTOT ratio ranged from 7.0 to 10.4 and did not vary significantly downcore at any one station. Values of delta 13CORG and delta 15NTOT in the sediment samples were strongly correlated, with the highest values, indicative of a more marine contribution, in the Amundsen Gulf. In contrast, the organic matter content, elemental (CORG:NTOT ratio) and isotopic (delta 13CORG and delta 15NTOT) composition of the settling particles was different from and much more variable than in the bottom sediments. The isotopic signature of organic matter in the Beaufort Sea is well constrained by three distinct end-members: a labile marine component produced in situ by planktonic organisms, a refractory marine component, the end product of respiration and diagenesis, and a refractory terrigenous component. A three-component mixing model explains the scatter observed in the stable isotope signatures of the sediment trap samples and accommodates an apparent two-component mixing model of the organic matter in sediments. The suspended matter in the water column contains organic matter varying from essentially labile and marine to mostly refractory and terrigenous. As it settles through the water column, the labile marine organic matter is degraded, and its original stable isotope signature changes towards the signature of the marine refractory component. This process continues in the bottom sediment with the result that the sedimentary organic matter becomes dominated by the refractory terrigenous and marine components. (Au)

B, F, D, J, A, H, E
Algae; Aluminum; Biological productivity; Bottom sediments; Carbon; Carbon cycling; Chemical properties; Climate change; Continental shelves; Cores; Estuaries; Isotopes; Mass spectrometry; Measurement; Nitrogen; Particulate organic matter; Peat; Physical properties; Plankton; River deltas; River discharges; Rivers; Seasonal variations; Sediment transport; Suspended solids

G0815, G07, G04, G03, G0812, G06
Amundsen Gulf, N.W.T.; Arctic Ocean; Beaufort Sea; Chukchi Sea; Colville Delta, Alaska; Kugmallit Valley, Canadian Beaufort Sea; Mackenzie Delta, N.W.T.; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Regional and seasonal variability of zooplankton collected using sediment traps in the southeastern Beaufort Sea, Canadian Arctic   /   Makabe, R.   Hattori, H.   Sampei, M.   Ota, Y.   Fukuchi, M.   Fortier, L.   Sasaki, H.
(Polar biology, v. 33, no. 2, Feb. 2010, p. 257-270, ill., map)
References.
ASTIS record 71843.
Languages: English
Web: doi:10.1007/s00300-009-0701-7
Libraries: ACU

Time-series sediment traps were deployed at six mooring sites in the southeastern Beaufort Sea from October 2003 to August 2004 during the cruise of the Canadian research vessel Amundsen within the framework of the Canadian Arctic Shelf Exchange Study (CASES). Trap-collected zooplankton (TCZ) at around 200 m water depth was dominated by copepods accounting for 74-93% of the total abundance throughout the year with increase in abundance at all sites during the fall. Seven distinct TCZ groups were identified through cluster analysis. Two marked seasonal shifts in TCZ composition from late fall to early winter and from spring to early summer were revealed at five sites at 200 m depth. The zooplankton was dominated by Oncaea spp., pteropods, and copepod nauplii in the late fall cluster and in the winter cluster, and by copepod nauplii in the summer cluster. A significant change in water temperature, salinity, and sea ice concentration was observed only with the spring-summer shift. The cluster analysis also revealed that TCZ composition at 200 m at a station located in the Cape Bathurst Polynya was markedly different from those at other sites through the study period by being characterized by the dominance of various copepodite stages of Metridia longa. This was probably due to a less prolonged period of sea ice cover, which provides favorable food conditions for the zooplankton community. (Au)

I, D, G, B, J
Amphipoda; Animal distribution; Animal food; Animal population; Animal taxonomy; Animal waste products; Bathymetry; Biological productivity; Biological sampling; Biomass; Bottom sediments; Continental shelves; Copepoda; Formation; Gender differences; Ice cover; Ice leads; Invertebrate larvae; Invertebrates; Marine ecology; Measurement; Movement; Ocean currents; Ocean temperature; Oceanographic instruments; Polynyas; Salinity; Sea ice; Seasonal variations; Sedimentation; Temporal variations; Water masses; Winter ecology; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Mackenzie Trough, Canadian Beaufort Sea


Correcting for beam spread in acoustic Doppler current profiler measurements   /   Marsden, R.F.   Ingram, R.G.
(Journal of atmospheric and oceanic technology, v. 21, no. 9, Sept. 2004, p.1491-1498, ill.)
References.
ASTIS record 63274.
Languages: English
Web: doi:10.1175/1520-0426(2004)021<1491:CFBSIA>2.0.CO;2
Libraries: ACU

Spatial homogeneity assumptions inherent in the conversion of directly measured acoustic Doppler current profiler (ADCP) beam to Cartesian coordinates for the Janus configuration are investigated. These assumptions may be adequate for large-scale flows, such as tidal currents and wind-forced upwelling. However, for high-frequency features, such as internal solitons and turbulence, the velocity fields may vary over scales comparable to the divergence of the acoustic beams. Equations are derived for beam spreading, and it is shown that a first-order correction can be applied to improve velocity measurement accuracy. Two cases are examined. First, the effects of the spatial and temporal convolution inherent in beam spreading from the Janus configuration ADCP are applied to a model internal solitary wave. It is shown that the corrected vertical velocities have deviations of less than 2 mm/s for distances up to 30 m from the transducer face and are approximately 3 times more accurate than the uncorrected velocities for distance up to 20 m from the transducer face. Next, under a "frozen turbulence" hypothesis, the method is applied to processing turbulence data. It is demonstrated that the horizontal longitudinal velocity can be markedly improved. (Au)

D
Acoustic properties; Internal waves; Mathematical models; Measurement; Ocean currents; Ocean waves; Oceanographic instruments; Sonar; Tides; Velocity; Water masses

G02
Arctic waters


Distribution and abundance of uncultured heterotrophic flagellates in the world oceans   /   Massana, R.   Terrado, R.   Forn, I.   Lovejoy, C.   Pedrós-Alió, C.
(Environmental microbiology, v. 8, no. 9, Sept. 2006, p.1515-1522, ill.)
References.
ASTIS record 65876.
Languages: English
Web: doi:10.1111/j.1462-2920.2006.01042.x
Libraries: ACU

Heterotrophic flagellates play fundamental roles in marine ecosystems as picoplankton grazers. This recognized importance contrasts with our ignorance of the taxonomic composition of this functional group, which remains mostly unidentified by microscopical and culturing approaches. Recent molecular marine surveys based on 18S rDNA genes have retrieved many sequences unrelated to cultured organisms and marine stramenopiles were among the first reported uncultured eukaryotes. However, little is known about the organisms corresponding to these sequences. Here we determine the abundance of several marine stramenopile lineages in surface marine waters using molecular probes and fluorescent in situ hybridization. We show that these protists are free-living bacterivorous heterotrophic flagellates. They were widely distributed, occurring in the five world oceans, and accounted for a significant fraction (up to 35%) of heterotrophic flagellates in diverse geographic regions. A single group, MAST-4, represented 9% of cells within this functional assemblage, with the intriguing exception of polar waters where it was absent. MAST-4 cells likely contribute substantially to picoplankton grazing and nutrient re-mineralization in vast areas of the oceans and represent a key eukaryotic group in marine food webs. (Au)

I, H, J, D
Animal distribution; Animal food; Animal population; Animal taxonomy; Chlorophyll; Fluorometry; Food chain; Genetics; Marine ecology; Microbial ecology; Microorganisms; Ocean temperature; Plankton; Size; Trophic levels

G03, G07, G0815, G05, G11, G15
Amundsen Gulf, N.W.T.; Antarctic waters; Arctic Ocean; Canadian Beaufort Sea; Indian Ocean; Mediterranean Sea; North Atlantic Ocean; North Pacific Ocean


Canadian Beaufort Sea ecosystem : a fisheries perspective   /   Mathias, J.   Fisheries Joint Management Committee (Canada) [Sponsor]   Oceans North Canada [Sponsor]
Inuvik, N.W.T. : Canada/Inuvialuit Fisheries Joint Management Committee, 2013.
viii, 111 p. : ill., maps ; 28 cm.
(Canada/Inuvialuit Fisheries Joint Management Committee technical report, 2013- 01)
Appendices.
References.
Indexed a PDF file from the Web.
ASTIS record 78754.
Languages: English
Web: http://www.oceansnorth.org/sites/default/files/attachments/Mathias%202013%20-%20FJMC%20Technical%20Report%202013-01.pdf

Climate change on the Canadian Beaufort Sea continental shelves is expected to lengthen the growing season and increase the open-water area, exposing the shelves to industrial development, including commercial fishing. Primary productivity and secondary fish productivity are currently low, but both are expected to increase in coming decades. Arctic cod, a likely target for commercial fishing, is the most abundant marine forage fish and a keystone species in Beaufort Sea food webs. Predators that depend on Arctic cod, directly or indirectly, are beluga whales, ringed seals, polar bears, and Arctic charr. Arctic cod needs to remain at its carrying capacity so that food stress is not placed upon its dependent predators at a time when they themselves are adjusting to a changing climate. The Mackenzie Shelf near Cape Bathurst is an area of upwelling and enhanced primary and secondary productivity characterized by a distinctive benthic community. Commercial fishing could impact this habitat, important for bowhead whales and thousands of diving sea birds. There are many effects and uncertainties associated with climate change that make predictions about species responses impossible at the present time, although various possibilities and probabilities are discussed. Specific recommendations for the monitoring of fisheries, food webs, habitats, and marine productivity are offered that, if incorporated into an integrated fisheries management plan, will help forecast how the Beaufort marine ecosystem will respond. (Au)

I, N, E, D, G, J, T
Animal distribution; Animal food; Arctic cod; Benthos; Biological productivity; Carbon cycling; Climate change; Co-management; Coast changes; Continental shelves; Ducks; Effects monitoring; Environmental impacts; Erosion; Estuarine ecology; Fish management; Fisheries; Fishes; Food chain; Marine ecology; Marine mammals; Melting; Meteorology; Oceanography; Primary production (Biology); River discharges; Sea ice; Sea ice ecology; Subsistence; Wildlife habitat; Winds

G07
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Bathurst, Cape, N.W.T.; Canadian Beaufort Sea; Darnley Bay, N.W.T.; Franklin Bay, N.W.T.; Liverpool Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.


Phytoplankton community adaptation to changing light levels in the southern Beaufort Sea, Canadian Arctic   /   Matsuoka, A.   Larouche, P.   Poulin, M.   Vincent, W.   Hattori, H.
(Estuarine, coastal and shelf science, v. 82, no. 3, 30 Apr. 2009, p. 537-546, ill., maps)
References.
ASTIS record 71807.
Languages: English
Web: doi:10.1016/j.ecss.2009.02.024
Libraries: ACU

The chlorophyll a specific absorption coefficient of phytoplankton, alpha*phi(lambda) is an important parameter to determine for primary production models and for the estimation of phytoplankton physiological condition. Knowledge of this parameter at high latitudes where nutrient rich cold water submitted to low incident light is a common environment is almost nonexistent. To address this issue, we investigated the light absorption properties of phytoplankton as a function of irradiance, temperature, and nutrients using a large data set in the southern Beaufort Sea during the open water to ice cover transition period. The alpha*phi(lambda) tended to increase from autumn when open water still existed to early winter when sea ice cover was formed, resulting from a biological selection of smaller-size phytoplankton more efficient to absorb light. There was no significant correlation between alpha*phi(lambda) and irradiance or temperature for both seasons. However, alpha*phi(lambda) showed a significant positive correlation with NO3 + NO2. Implications of the results for phytoplankton community adaptation to changing light levels are discussed. (Au)

H, D, E, G, J, F
Adaptation (Biology); Chlorophyll; Climate change; Effects of climate on plants; Environmental impacts; Food chain; Light; Marine ecology; Ocean temperature; Oceanography; Optical properties; Phytoplankton; Plant growth; Plant nutrition; Plant physiology; Primary production (Biology); River discharges; Salinity; Sea ice; Seasonal variations; Sediment transport; Size; Spatial distribution; Temporal variations; Trophic levels; Water masses

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Mackenzie Bay, N.W.T./Yukon; Mackenzie River, N.W.T.


A synthesis of light absorption properties of the Pan-Arctic Ocean : application to semi-analytical estimates of dissolved organic carbon concentrations from space   /   Matsuoka, A.   Babin, M.   Doxaran, D.   Mitchell, B.G.   Bélanger, S.   Bricaud, A.
(Biogeosciences discussions, v. 10, no. 11, 2013, p.17071-17115, ill., maps)
Open access.
References.
Appendix.
ASTIS record 80092.
Languages: English
Web: doi:10.5194/bgd-10-17071-2013
Libraries: ACU

The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean (e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012), the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off North America. In contrast, the relationship between the phytoplankton absorption (alpha phi (lambda)) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific (alpha phi (lambda)) values (Matsuoka et al., 2013), this result indirectly suggests that CDOM absorption can be appropriately derived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC vs. CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data. (Au)

D, F, H, I
Chemical oceanography; Chlorophyll; Climate change; Colored dissolved organic matter; Continental shelves; Dissolved organic carbon; Environmental impacts; Fluorometry; Instruments; Light; Mass spectrometry; Mathematical models; Measurement; Microorganisms; Numeric databases; Ocean temperature; Optical properties; Photosynthesis; Physical properties; Phytoplankton; Primary production (Biology); Remote sensing; River discharges; Salinity; Satellite photography; Sea water; Seasonal variations; Sediment transport; Solar radiation; Spatial distribution; Suspended solids; Temporal variations; Ultraviolet radiation; Water masses

G07, G03, G04, G141
Arctic Ocean; Canadian Beaufort Sea; Chukchi Sea; Russian Arctic waters


Oceanography of the Northwest Passage (26,P)   /   McLaughlin, F.A.   Carmack, E.C.   Ingram, R.G.   Williams, W.J.   Michel, C.
In: The sea : ideas and observations on progress in the study of the seas. Volume 14 : the global coastal ocean : interdisciplinary regional studies and syntheses. Part B : the coasts of Africa, Europe, Middle East, Oceania and polar regions / Edited by Allan R. Robinson and Kenneth H. Brink. - Cambridge, Mass. : Harvard University Press, 2006, ch. 31, p.1213-1244, ill., maps
Cover title of the larger work: The sea : the global coastal ocean : interdisciplinary regional studies and syntheses.
Abbreviated title of the larger work: The sea : ideas and observations on progress in the study of the seas, v. 14, part B.
Title page title of the larger work: The global coastal ocean : interdisciplinary regional studies and syntheses. ... Part B: The coasts of Africa, Europe, Middle East, Oceania and polar regions. ... The sea : ideas and observations on progress in the study of the seas, volume 14, part B.
References.
ASTIS record 63315.
Languages: English
Libraries: ACU

... It is our intent to review the general features of the CAA [Canadian Arctic Archipelago] with particular focus on the NWP [Northwest Passage]. We summarize the basic physical, chemical and biological features of the region, and examine the dynamical constraints governing the movement of water masses through the system. Data from the direct (deepwater) NWP is presented: that is, the West-East passage that connects M'Clure Strait with Lancaster Sound via Barrow Strait. ... The CAA has long been considered an oceanographic backwater by both observations and modellers, largely because of logistical difficulties, dynamical complexity, economic insignificance and a general lack of appreciation for its connectivity to the global system. It is now recognized, however, that the CAA plays a critical role in global climate, mainly through the export of ice and low salinity waters to the convective centers of the North Atlantic .... Abrupt changes in global climate during the last glacial epoch, such as Heinrich events, have been explained by releases of massive volumes of glacial ice from the CAA .... On decadal time scales, fluctuations in the export of fresh water from the Arctic Ocean may alter conditions downstream in the Labrador Sea and North Atlantic ... and as far south as the shelf waters of the Middle Atlantic Bight .... Recent models have demonstrated the climatic importance of freshwater transport from the Pacific to the Atlantic via Bering Strait ... and via the CAA .... Processes within the CAA may impact global climate, but, global climate change may also alter conditions with the CAA: both aspects of this "two-way street" must be considered. The consequences of global climate evolution on ice and oceanographic conditions in the CAA under scenarios of greenhouse gas (GHG) warming are especially topical. Such changes will clearly impact transportation, resource development and human settlement. Most coupled air/ice/sea GCMs predict a warming of the CAA and a significant reduction in ice cover through the 21st century (cf. Arctic Climate Impact Assessment, 2004). However, much uncertainty exists. ... a thinning and reduction in landfast ice in the CAA may simply allow a greater advection of multi-year floes from the Arctic Ocean into the CAA which would act as an impediment to marine transportation. Increased precipitation, also predicted under GHG warming scenarios, may lead to thicker snow-on-ice, and this insulating effect may impact ice thickness more than changes in temperature .... Due to increased net precipitation in the high-latitudes, some models predict a counter-intuitive slowing-down of the thermohaline circulation, and a subsequent cooling of northern Europe .... Such uncertainty in both the sign and magnitude of change can only be reduced by better understanding and parameterization of the processes and feedbacks that govern the high-latitude disposition and export of freshwater components .... The ecological impacts of anticipated changes in the CAA deserve special attention. ... climate change in regions currently covered by ice will affect the structure of marine ecosystems through both bottom-up and top-down reactions. Bottom-up changes in trophic structure would be the result of changes in ice cover extent that affect underwater light, mixing and nutrient fluxes into the euphotic zone. ... Top-down changes would be the result of changes in the distribution and abundance of ice-dependant predators at various levels within the food-web and downward cascading of grazing effects. ... One might hope that the passion of the 19th century explorers to map the NWP will be re-kindled in the curiosity of 21st century scientists to understand and model this complex and important system. (Au)

D, F, E, G, J, I, H
Algae; Amphipoda; Arctic cod; Bathymetry; Benthos; Biological productivity; Biomass; Climate change; Continental shelves; Copepoda; Density; Environmental impacts; Flow; Food chain; Formation; Hydrology; Ice cover; Light; Marine ecology; Marine mammals; Mercury; Meteorology; Nitrogen; Ocean currents; Ocean temperature; Oceanography; Oxygen; Phosphorus; Phytoplankton; Plant nutrition; Polynyas; POPs; River discharges; Salinity; Sea birds; Sea ice; Sea ice ecology; Sea level; Seasonal variations; Silicates; Solar radiation; Submarine topography; Thickness; Tides; Velocity; Water masses; Zooplankton

G0815
Barrow Strait, Nunavut; Canadian Arctic Islands waters; Lancaster Sound, Nunavut; M'Clure Strait, N.W.T.; Northwest Passage


Cruise report : Joint Western Arctic Climate Study 2002, Canadian Arctic Shelf Exchange Study, Beaufort Sea : CCGS Sir Wilfrid Laurier, September 6 - September 24, 2002 : Institute of Ocean Sciences Cruise 2002-21   /   Melling, H. [Chief Scientist]
Québec, Québec : Université Laval, 2002.
15 p. : ill., maps ; 28 cm.
Appendices.
Cover title.
Running title: Science cruise report - CCGS Sir Wilfrid Laurier, September 2002.
Indexed a PDF file from the Web.
ASTIS record 74419.
Languages: English
Web: http://www.quebec-ocean.ulaval.ca/cases/Laurier%202002%20Science%20Cruise%20report.pdf

Overview: The Joint Western Arctic Climate Study (JWACS) is a bilateral research initiative (Canada and Japan) in the Canada Basin of the Arctic Ocean. The principal agencies are the Japan Marine Science and Technology Centre (JAMSTEC) and the Canadian Institute of Ocean Sciences. In 2002, the study was conducted simultaneously in both the ice-covered and ice-free zones of the southern Canada Basin in late summer. The scope was multi-disciplinary, embracing study of seabed geomorphology, physical oceanography, sea ice, tracer geochemistry and marine biology in the benthic, pelagic and epontic domains. Collaborators joined from university and other governmental agencies in Canada, Japan, USA and the UK. Three ships were involved in JWACS: the Mirai, the CCGS Louis S St-Laurent and the CCGS Sir Wilfrid Laurier. The Mirai worked in the ice-free part of the study area, the Louis in the heavy ice and the Laurier along the interface between the two zones. The primary responsibilities of the CCGS Sir Wilfrid Laurier within JWACS were the recovery and deployment of the oceanographic moorings used in collecting long time series of ocean and ice data in the Beaufort Sea. The Canadian Arctic Shelf Exchange Study (CASES) was initiated in 2002 with the deployment of oceanographic moorings in the eastern Beaufort Sea and the conduct of a baseline survey of the marine ecosystem and its relationship to ice extent in the autumn. The mooring component of CASES was completed from the CCGS Sir Wilfrid Laurier, employing the experienced mooring team already on board for the JWACS mooring work. The CASES oceanographic survey was conducted from the CCGS Pierre Radisson, between September 23 and October 16 2002. Goal: The primary objective of the research in 2002 was an improved understanding of the character and causes of variability and change in Canada Basin. We do not yet know whether the dramatic changes in the oceanography and ice cover of the Arctic Ocean during the 1990's were consequences of an anthropogenic shift in the climate of the North Polar Region, or whether they reflect natural decadal variability in the ocean-ice-atmosphere system. The secondary objective was improved understanding of the influence of topography on the exchange of waters between the continental shelf and the ocean basin. Moorings were sited to measure circulation and upwelling in two large sea valleys that cut deeply into the continental shelf of the Beaufort Sea, namely Barrow Canyon and Herschel Canyon. Hydrographic surveys explored nutrient regeneration, oxygen depletion and the renewal of deep waters in the three sub-basins of Amundsen Gulf. A mooring in the deep central basin of Amundsen Gulf carried instruments to measure the carbon flux and associated oceanographic conditions. (Au)

D, G, E, B, H, I, J, L
Benthos; Biological sampling; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chemical oceanography; Chlorophyll; Climate change; Coast changes; Data buoys; Equipment and supplies; Geochemistry; Hydrography; Ice scouring; Ice shelves; Instruments; Measurement; Meteorology; Ocean temperature; Ocean waves; Ocean-atmosphere interaction; Oceanography; Salinity; Sea ice; Sea water; Seasonal variations; Sir Wilfrid Laurier (Ship); Sonar; Storage; Submarine topography; Suspended solids; Temporal variations; Water masses

G07, G03, G0815
Amundsen Gulf, N.W.T.; Beaufort Sea; Canada Basin, Arctic Ocean; Kugmallit Valley, Canadian Beaufort Sea; Tuktoyaktuk waters, N.W.T.


An ocean of data : the CASES legacy   /   Michaud, J.   Braithwaite, L.   Garneau, M.-È.   Barnard, C.   Vincent, W.F.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 10, p. 201-211, ill.
Appendix.
References.
ASTIS record 67493.
Languages: English
Libraries: ACU

... Detection of environmental trends requires well-documented and consistent time-series information. With the increasing evidence of rapid environmental changes in Polar Regions, data description (i.e. meta-data standardization), archiving and open access have become key issues in Arctic and Antarctic research programs. ... the CASES Research Network has made metadata/data archiving one of its primary objectives. CASES represents one of the most ambitious multidisciplinary and international efforts to understand the biogeochemical and ecological impacts of the present decline in Arctic sea ice cover. Its scientific program encompassed ail fields of oceanography and atmospheric sciences in an attempt to better understand the overall Arctic ecosystem. In keeping with IPY philosophy, multidisciplinary datasets resulting from this initiative will form the basis for several hundred publications and provides an important legacy to Arctic Ocean research. Therefore, data must be archived in a manner that will ensure long-term accessibility to the scientific community and to the public. CASES datasets are varied and numerous, having been generated by eight subprojects within the program's mandate (Appendix 10.1). The CASES Research Network has involved over 50 principal investigators (PIs) and their research teams, representing a diversity of disciplines and institutions from Canada and abroad. The varied approaches to data management among individual laboratories, disciplines and institutions has represented a significant challenge in ensuring that CASES data is preserved adequately and is easily accessible, but while preserving the rights of the data originator(s) for publication. In keeping with this, the objectives of the CASES Data Management and Archive Strategy were to ensure that all data are: integrated into comprehensive data bases; available to all participants of the CASES Research Network under conditions that respect the rights of the data originator(s); archived and ultimately accessible to the broader scientific community and the public; and available to researchers in other national and international polar research programs such as ArcticNet and IPY. ... (Au)

Y
Archives; Canadian Arctic Shelf Exchange Study; Databases; Electronic data processing; Information services; Research; World Wide Web

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


CASES2003, Leg 2 (0304) CCGS Amundsen cruise report 16 October to 26 November   /   Miller, L. [Editor]
Québec, Québec : Université Laval, 2003.
85 p. : ill., maps ; 28 cm.
Appendices.
Cover title.
Indexed a PDF file from the Web.
References.
ASTIS record 74422.
Languages: English
Web: http://www.quebec-ocean.ulaval.ca/cases/CASES0304_leg2_cruise_report.pdf

This report describes the scientific studies, meteorological difficulties, equipment failures and logistical problems confronting Leg 2 of the CCGS Amundsen cruise. The scientific observations included: 1. Atmospheric & Sea Ice Forcing of Coastal Circulation; 2. Ice-atmosphere Interactions and Biological Linkages; 2.1 Micrometeorology; 2.2 Free drifting sediment traps on newly formed sea-ice; 2.3 Surface EM Measurements; 2.4 Aerial Surveys; 2.5 Ice Raid and Ice Microstructure; 3. Light, Nutrients, Primary and Export Production; 3.1 CDOM in Surface Waters; 3.2 Phytoplankton and Microphytobenthos Characteristics; 4. Microbial Communities and Heterotrophy; 4.1 Microbial Ecology; 4.2 Seasonal Microbial Community Diversity, Strucutre and Function; 5. Pelagic Food Web: Structure, Function and Contaminants; 5.1 Zooplankton and Larval Fish Dynamics; 5.2 Evolution of Arctic Arthropoda; 6. Organic and Inorganic Fluxes; 6.1 Stable Isotopes; 6.2 Water Column Carbon Geochemistry; 7. Benthic Processes & Carbon Cycling; 7.1 Benthic Processes; 7.2 Sediment Geochemistry. (ASTIS)

D, G, E, B, H, I, J, L, K, T
Amundsen (Ship); Benthos; Biological sampling; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chemical oceanography; Climate change; Cold weather performance; Colored dissolved organic matter; Cores; Data buoys; Environmental impacts; Equipment and supplies; Fishes; Food chain; Frostbite; Geochemistry; Hydrography; Ice cover; Instruments; Inuit; Light; Marine ecology; Marine mammals; Measurement; Meteorology; Microbial ecology; Ocean temperature; Ocean waves; Ocean-atmosphere interaction; Phytoplankton; Pollution; Primary production (Biology); River discharges; Salinity; Scientists; Sea ice; Sea ice ecology; Seasonal variations; Snowmobiles; Sonar; Suspended solids; Temporal variations; Traditional knowledge; Trafficability; Viruses; Water masses; Zooplankton

G07, G0812, G0815
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Beaufort Sea; Franklin Bay, N.W.T.


Carbon dynamics in sea ice : a winter flux time series   /   Miller, L.A.   Papakyriakou, T.N.   Collins, R.E.   Deming, J.W.   Ehn, J.K.   Macdonald, R.W.   Mucci, A.   Owens, O.   Raudsepp, M.   Sutherland, N.
(Journal of geophysical research, v.116, C02028, 2011, 20 p., ill., maps)
References.
ASTIS record 74354.
Languages: English
Web: doi:10.1029/2009JC006058
Libraries: ACU

A winter time series of the inorganic carbon system above, within, and beneath the landfast sea ice of the southern Beaufort Sea confirmed that sea ice is an active participant in the carbon cycle of polar waters. Eddy covariance measurements above the ice identified significant vertical CO2 fluxes, mostly upward away from the ice but with short periods of downward fluxes as well. A novel, in situ method revealed extremely high rho CO2 values within the ice that are not inconsistent with theory. The total carbon content of the ice increased slightly through the winter season, and increasing variability in the vertical profiles as spring began indicated that the inorganic carbon became mobile as the ice began to melt. During early winter, as the ice formed, inorganic carbon concentrations in the surface waters increased dramatically, along with salinity, partly because of rejection from the ice and partly from advective mixing. Brine drainage was apparently not sufficient to initiate convection, and the excess carbon remained in the surface waters into the summer. (Au)

G, D, E, F, H, J
Algae; Atmospheric chemistry; Bacteria; Bathymetry; Biological sampling; Biomass; Carbon; Carbon cycling; Carbon dioxide; Chemical oceanography; Chemical properties; Chlorophyll; Cores; Diurnal variations; Fast ice; Formation; Gases in ice; Mathematical models; Ocean temperature; Ocean-atmosphere interaction; Photosynthesis; Plant respiration; Primary production (Biology); Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Snow; Surface properties; Temperature; Temporal variations; Thickness; Water masses; Winds

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Radiometric measurements of air-sea and air-ice temperature differences in the Arctic   /   Minnett, P.J.
In: IGARSS 2003 : learning from Earth's shapes and sizes : 2003 IEEE International Geoscience and Remote Sensing Symposium : proceedings : Centre de Congrès Pierre Baudis, Toulouse, France, 21-25 July 2003. - Piscataway, N.J. : Institute of Electrical and Electronics Engineers, 2003, v. 1, p. 273-275, ill., maps
Indexed a PDF file from the Web.
References.
INSPEC accession number: 7953601.
Alternate title: Geoscience and Remote Sensing Symposium, 2003. IGARSS '03. Proceedings. 2003 IEEE International.
ASTIS record 63297.
Languages: English
Web: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1293748&isnumber=28601
Libraries: ACU

The polar regions are considered to be particularly sensitive to climate change. The complex interactions between the surface and the overlying atmosphere are important aspects of the local heat budget, and through the atmospheric and oceanic general circulations, to global scales. The temperature difference between the surface and the lowest layer of the air is an important parameter in the surface heat budget, but difficult to measure, especially in conditions of mixed sea-ice and open water. Both surface temperature and near-surface air temperature can be determined radiometrically from measurements of the infrared emission spectra of the surface and atmosphere. The use of a Fourier-transform infrared spectroradiometer, the M-AERI (Marine-Atmospheric Emitted Radiance Interferometer) on ships can provide such data. (Au)

A, E, G, D
Atmospheric temperature; Boundary layers; Canadian Arctic Shelf Exchange Study; Heat budgets; Ice cover; Infrared radiation; Infrared remote sensing; Instruments; Measurement; Ocean temperature; Ocean-atmosphere interaction; Polynyas; Sea ice; Surface temperature

G07, G0813, G0815
Canadian Beaufort Sea; Mackenzie Estuary, N.W.T./Yukon; Northwest Passage; Queen Elizabeth Islands waters, N.W.T./Nunavut


Infrared interferometric measurements of the near-surface air temperature over the oceans   /   Minnett, P.J.   Maillet, K.A.   Hanafin, J.A.   Osborne, B.J.
(Journal of atmospheric and oceanic technology, v. 22, no. 7, July, 2005, p.1019-1032, ill.)
References.
ASTIS record 63276.
Languages: English
Web: doi:10.1175/jtech1756.1
Libraries: ACU

The radiometric measurement of the marine air temperature using a Fourier transform infrared spectroradiometer is described. The measurements are taken by the Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) that has been deployed on many research ships in a wide range of conditions. This approach is inherently more accurate than conventional techniques and can be used to determine some of the error characteristics of the standard measurements. Examples are given from several cruises ranging from the Arctic to the equatorial Pacific Oceans. It is shown that the diurnal heating signal in radiometric air temperatures in the tropical Pacific can typically reach an amplitude of ~15% of that measured by conventional sensors. Conventional data have long been recognized as being contaminated by direct solar heating and heat island effects of the ships or buoys on which they are mounted, but here this effect is quantified by comparisons with radiometric measurements. (Au)

E, D
Atmospheric temperature; Carbon dioxide; Diurnal variations; Infrared radiation; Instruments; Measurement; Optical properties; Spectroscopy; Surface temperature

G02, G05
Arctic waters; North Pacific Ocean


Sedimentary pigments as biomarkers of spatial and seasonal variations in Arctic pelagic-benthic coupling   /   Morata, N.   Renaud, P.E. [Supervisor]
Storrs, Conn. : University of Connecticut, 2007.
ix, 62, 17, 21, 17, 248-260, 1-12, 16, [6] p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. 3300638)
Appendices.
References.
Thesis (Ph.D.) - University of Connecticut, Storrs, Conn., 2007.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74785.
Languages: English

The Arctic Ocean is characterized by broad continental shelves, which have high rates of primary productivity. In some areas, much of this production falls to the bottom, supplying rich and active communities of benthic organisms. Benthic-pelagic coupling over much of the Arctic shelves is thought to be particularly tight. Moreover in areas covered by ice, ice algae can be the main source of carbon for the food web and thus for the benthos. Sedimentary pigments have demonstrated their usefulness in studies of ecosystem changes, and especially changes of organic matter inputs to the benthos. In order to characterize variation in pelagic-benthic coupling in the Arctic, sedimentary pigments were studied in the oligotrophic Beaufort Sea (CASES project) and in the more productive Barents Sea (CABANERA project). During 7 cruises from 2003 to 2005, sediment cores, water column POM and ice algae samples have been collected, representing a significant spatial coverage and seasonal variations. Sedimentary pigments reflected changes in environmental factors, sources of primary productivity, food web structure, and benthic activity. The Beaufort Sea and Barents Sea showed very different pelagic-benthic coupling, reflecting the important contrast between the two ecosystems of primary productivity, secondary production, and hydrography. In the Barents Sea, spatial changes were highly influenced by currents while in the Beaufort Sea, spatial changes were due to depth and river influence. Physical parameters seemed more responsible of spatial changes. From a seasonal point of view, productivity regime, especially ice-algal production and the match/mismatch of grazing, seemed important in shaping organic matter inputs to the benthos. In the spring, ice-algal production largely influenced organic matter inputs to the benthos in both the Barents and Beaufort Seas. In the summer, grazing was responsible for inputs of degraded material in both ecosystems. In addition to biological parameters, environmental factors were also important in summer and/or fall. In the Barents Sea during summer, the different currents lead to phytoplankton taxonomy variations, and in the Beaufort Sea during fall, riverine inputs were found to be responsible for presence of allochtonous material in the sediment. (Au)

H, B, D, J, I, F, G
Algae; Animal distribution; Animal ecology; Animal food; Animal respiration; Animal waste products; Bacteria; Bathymetry; Benthos; Biological productivity; Biological sampling; Biomass; Bottom sediments; Carbon; Carbon cycling; Chlorophyll; Cores; Crustacea; Cyanophyceae ; Diatoms; Dinoflagellata ; Echinoderms; Fast ice; Food chain; Grazing; Ice cover; Invertebrates; Isotopes; Marine ecology; Nitrogen; Ocean currents; Ocean temperature; Oxygen; Particulate organic matter; Photosynthesis; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Plant respiration; Primary production (Biology); Rivers; Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Sedimentation; Spatial distribution; Suspended solids; Temporal variations; Theses; Thickness; Zooplankton

G07, G0815, G0812, G141
Alaskan Beaufort Sea; Amundsen Gulf, N.W.T.; Barents Sea; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.


Spatial and seasonal variations in the pelagic-benthic coupling of the southeastern Beaufort Sea revealed by sedimentary biomarkers   /   Morata, N.   Renaud, P.E.   Brugel, S.   Hobson, K.A.   Johnson, B.J.
(Marine ecology. Progress series (Halstenbek), v.371, Nov. 19, 2008, p. 47-63, ill., maps)
References.
ASTIS record 66709.
Languages: English
Web: doi:10.3354/meps07677
Libraries: ACU

Photosynthetic pigments and stable isotopes from suspended particulate organic matter (POM) and surface sediment of the southeast Beaufort Sea, including the Mackenzie shelf and the Amundsen Gulf, were studied during fall 2003 and summer 2004. This multiple-biomarker approach led to an increased understanding of spatial and seasonal variation in pelagic-benthic coupling, as these 2 biomarkers reflect inherent differences in the time scales over which they integrate. Sedimentary pigments highlighted the importance of local water-column production as a source of phytodetrital inputs to the sea floor. In the summer, the dominance of diatoms in the water column was reflected in the sediment by the abundance of fucoxanthin, a pigment broadly found in diatoms. In the fall, a more variable suite of sedimentary pigments reflected inputs from smaller cells such as haptophytes and prasinophytes. While stable isotope composition of the POM showed seasonal variations, i.e. a more marine signature in the summer and a more terrestrial signature in the fall, sedimentary stable isotopes revealed geographical differences. Sediment on the Mackenzie shelf suggested a terrestrial source of organic matter, while in the Amundsen Gulf, sources of organic matter had a more marine origin. Finally, benthic community compositions and activity (sediment carbon demand) seemed affected by both spatial and seasonal variations in organic matter inputs to the benthos. This study stresses the importance of both physical factors (water depth and riverine inputs) and biological production (primary productivity and secondary production) in the determination of organic matter inputs to the benthos. (Au)

H, B, D, J, F, I
Algae; Animal food; Bathymetry; Benthos; Biological productivity; Bottom sediments; Carbon; Carbon cycling; Chlorophyll; Chromatography; Cores; Cyanophyceae ; Diatoms; Dinoflagellata ; Fluorometry; Isotopes; Mass spectrometry; Nitrogen; Particulate organic matter; Photosynthesis; Phytoplankton; Plant distribution; Plant nutrition; Rivers; Sea water; Seasonal variations; Sedimentation; Spatial distribution; Suspended solids; Zooplankton

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.


Pelagic-benthic coupling of the Barents and Beaufort Seas, Arctic, revealed by sedimentary pigments   /   Morata, N.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 272
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67289.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Pelagic-benthic coupling over much of the Arctic shelves is thought to be particularly tight. The study of sedimentary pigments in the Barents and Beaufort Seas showed very different pelagic-benthic coupling patterns, reflecting the important contrast of primary productivity, secondary production, and hydrography between the two ecosystems. Physical parameters seemed more responsible for spatial differences. In the Barents Sea, spatial changes were highly influenced by currents while in the Beaufort Sea, spatial changes were related to depth and river influence. From a seasonal point of view, productivity regime, especially ice-algae production and the match/mismatch of zooplankton grazing, seemed important in shaping organic matter inputs to the benthos. In the spring, ice-algal production largely influenced organic matter inputs to the benthos in both the Barents and Beaufort Sea. In the summer, grazing was responsible for inputs of degraded material in both ecosystems. In addition to biological parameters, environmental factors were also important in summer and fall. In the Barents Sea during summer, the different currents lead to phytoplankton taxonomy variations, and in the Beaufort Sea during fall, riverine inputs were found to be responsible for the presence of allochtonous material in the sediment. (Au)

B, D, H, I, F, J
Algae; Animal distribution; Benthos; Biological productivity; Bottom sediments; Continental shelves; Marine ecology; Ocean currents; Plankton; Plant distribution; Plant taxonomy; Primary production (Biology); Rivers; Sea ice ecology; Seasonal variations; Spatial distribution

G141, G07
Barents Sea; Beaufort Sea


A multiple biomarker approach to tracking the fate of an ice algal bloom   /   Morata, N.   Poulin, M.   Renaud, P.E.
In: ArcticNet programme 2009 : annual scientific meeting, 8-11/12/2009, Victoria, B.C. = ArcticNet programme 2009 : réunion scientifique annuelle, 8-11/12/2009, Victoria, B.C. - [Québec, Québec] : ArcticNet, 2009, p. 59-60
Abstract of a Topical Session presentation.
Indexed a PDF file from the Web.
ASTIS record 73193.
Languages: English
Web: http://www.arcticnetmeetings.ca/docs/asm2009_programme_long.pdf
Libraries: ACU

In ice-covered areas in the Arctic, production by ice algae can be the main input of organic matter to the ecosystem. Pelagic-benthic coupling is thought to be particularly tight in those areas. The increase of ice algal production in Franklin Bay from January/February to April/May 2004 was found to be accompanied by an increase in sediment oxygen demand (SOD, Renaud et al. 2007). However sedimentary chlorophyll a, which is usually an indicator of inputs of "fresh" organic matter to the sea floor, did not increase. Consequently, it was asked what was the fate of ice algal phytodetritus arriving at the sea floor? In order to answer that question, photosynthetic pigments from the sea ice, particulate organic matter, and sediment, and diatom frustules in the sediment, were studied from January to May 2004. Ice algal diatom cells in the sediment showed an increase in April/May, confirming the higher inputs of fresh ice algae to the sediment. Changes in sedimentary pigment profiles in the first 10 cm suggested an increase in sediment reworking due to the enhanced benthic activities. Finally, changes in phaeopigments composition and increase of total SOD vs. microfauna SOD implied an increase in macrobenthic activities. Benthic macrofauna consumed some of the deposited material and mixed some within the top five cm of sediment. The response of sedimentary pigments to an ice algae input can be studied at different levels and it is the combination of these studies that allows understanding the overall fate of phytodetritus in the benthic compartment. (Au)

H, I, B, G
Algae; Animal food; Benthos; Bottom sediments; Carbon; Chlorophyll; Diatoms; Oxygen; Particulate organic matter; Primary production (Biology); Sea ice; Seasonal variations; Sedimentation; Spatial distribution

G0815
Franklin Bay, N.W.T.


A multiple biomarker approach to tracking the fate of an ice algal bloom   /   Morata, N.   Poulin, M.   Renaud, P.E.
In: International Polar Year Oslo Science Conference, 2010, 8-12 June. - [Oslo : Research Council of Norway, 2010], presentation no. PS1-D.59, [1] p.
Abstract of a poster presentation, taken from the USB flash drive distributed at the conference.
ASTIS record 71717.
Languages: English

In ice-covered areas in the Arctic, production by ice algae can be the main input of organic matter to the ecosystem. Pelagic-benthic coupling is thought to be particularly tight in those areas. The increase of ice algal production in Franklin Bay from January/February to April/May 2004 was found to be accompanied by an increase in sediment oxygen demand (SOD, Renaud et al. 2007). However sedimentary chlorophyll a, which is usually an indicator of inputs of "fresh" organic matter to the sea floor, did not increase. Consequently, it was asked what was the fate of ice algal phytodetritus arriving at the sea floor? In order to answer that question, photosynthetic pigments from the sea ice, particulate organic matter, and sediment, and diatom frustules in the sediment, were studied from January to May 2004. Ice algal diatom cells in the sediment showed an increase in April/May, confirming the higher inputs of fresh ice algae to the sediment. Changes in sedimentary pigment profiles in the first 10 cm suggested an increase in sediment reworking due to the enhanced benthic activities. Finally, changes in phaeopigments composition and increase of total SOD vs. microfauna SOD implied an increase in macrobenthic activities. Benthic macrofauna consumed some of the deposited material and mixed some within the top five cm of sediment. The response of sedimentary pigments to an ice algae input can be studied at different levels and it is the combination of these studies that allows understanding the overall fate of phytodetritus in the benthic compartment. Keywords: pelagic-benthic coupling, sedimentary pigments, diatoms, Beaufort Sea. (Au)

H, B, G, D
Animal waste products; Benthos; Bottom sediments; Chlorophyll; Diatoms; Ice cover; Marine ecology; Marine flora; Ocean floors; Primary production (Biology); Sea ice; Sea water; Seasonal variations

G0815
Franklin Bay, N.W.T.


A multiple biomarker approach to tracking the fate of an ice algal bloom to the sea floor   /   Morata, N.   Poulin, M.   Renaud, P.E.
(Polar biology, v. 34, no. 1, Jan. 2011, p. 101-112, ill., maps)
References.
ASTIS record 71866.
Languages: English
Web: doi:10.1007/s00300-010-0863-3
Libraries: ACU

In ice-covered Arctic seas, the ice algal production can be the main input of organic matter to the ecosystem. Pelagic-benthic coupling is thought to be particularly tight in those areas. The increase in ice algal production in Franklin Bay from January/February to April/May 2004 paralleled an increase in benthic oxygen demand. However, sedimentary chlorophyll a, which is usually an indicator of "fresh" organic matter inputs to the sea floor, did not increase. Consequently, it was asked what was the fate of the ice algal phytodetritus arriving at the sea floor? To answer this question, photosynthetic pigments from the sea ice, water column particulate organic matter, and sediment, as well as diatom frustules in the sediment, were studied from January to May 2004. The number of ice diatom cells in the sediment showed an increase in April/May, confirming higher inputs of fresh ice algae to the sediment. Changes in sedimentary pigment profiles in the first 10 cm suggested an increase in bioturbation due to enhanced benthic activities. Finally, the decrease in the ratio of chlorophyll a to phaeophorbide a implied an increase in macrobenthic activity. Benthic macrofauna consumed some of the deposited material and mixed some within the top five cm of sediment. The response of sedimentary pigments to an ice algal input can be studied at different levels and it is only the combination of these studies that will allow an understanding of the overall fate of phytodetritus in the benthic compartment. (Au)

H, B, G, D, J, I
Algae; Animal waste products; Benthos; Bottom sediments; Carbon; Carbon cycling; Chlorophyll; Coring; Diatoms; Fast ice; Fluorometry; Food chain; Grazing; Ice cover; Isotopes; Marine ecology; Marine flora; Nitrogen; Ocean floors; Particulate organic matter; Photosynthesis; Primary production (Biology); Sea ice; Sea ice ecology; Sea water; Seasonal variations; Sedimentation; Temporal variations; Zooplankton

G0815
Franklin Bay, N.W.T.


Comparison of Late Holocene and Pleistocene sedimentologic and oceanographic records in the Amundsen Gulf, Northwest Territories, Canada   /   Moss, T.
(Atlantic Geoscience Society : abstracts : 2006 Colloquim & Annual General Meeting. Atlantic geology, v. 42, no. 1, Mar. 2006, p. 102)
The 32nd Colloquium and Annual General Meeting was held at the Old Orchard Inn, Greenwich, Nova Scotia on February 2 and 4, 2006.
ASTIS record 66705.
Languages: English
Libraries: ACU

Analysis of sediments of two box cores from Canadian Arctic Shelf Exchange Study (CASES), stations 403B (59 m) and 415B (56 m) located in the Amundsen Gulf, allow the determination of the sedimentologic and oceanographic records from the area. Arctic benthic foraminiferal assemblages of the Late Holocene (403B) and Pleistocene (415B) show differences in foraminifers between an environment of high sedimentation (core 403B) and an area of low sedimentation (415B) with evidence of erosion related to glaciation. This contrast will provide insight into glacial records and Arctic productivity. Potential impacts on the Arctic ecosystem need to be explored, since the Arctic is most vulnerable to changes in climate and specifically changes in sea ice cover. This study will contribute to the assessment of the factors that presently influence sea ice cover which are important in the understanding of the impacts on coastal shelf region of the Arctic. (Au)

B, D, I, J, A, F, G, E
Animal distribution; Benthos; Biological productivity; Bottom sediments; Climate change; Cores; Environmental impacts; Foraminifera; Glacial epoch; Glacial erosion; Ice cover; Palaeontology; Pleistocene epoch; Recent epoch; Sea ice; Sedimentation; Temporal variations

G0815
Amundsen Gulf, N.W.T.


Organic and inorganic fluxes   /   Mucci, A.   Forest, A.   Fortier, L.   Fukuchi, M.   Grant, J.   Hattori, H.   Hill, P.   Lintern, G.   Makabe, R.   Magen, C.   Miller, L.   Sampei, M.   Sasaki, H.   Sundby, B.   Walker, T.   Wassmann, P.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 7, p. 113-141, ill., maps
References.
ASTIS record 67482.
Languages: English
Libraries: ACU

... The southern Beaufort Sea and Mackenzie Shelf region appears to have been a net sink for atmospheric CO2 during the open water periods of the CASES expedition. Preliminary data also indicated a net CO2 drawdown from the atmosphere during the ice-covered season, implying that this area could be very important in regulating rising atmospheric CO2 levels .... From our single year of sampling (2003-2004), it is difficult to determine how robust the observed CO2 sink is .... the surface waters observed under the ice during CASES remained undersaturated throughout winter and into spring. This implies limited winter respiratory activity, and that a loss in ice cover would not result in dramatic wintertime outgassing. Therefore, we might predict that the observed sink could be quite robust but, at this time, it is still impossible to predict how the total effect of climate change would impact the balance between winter respiration and summer primary production. ... We report subtle changes in biological and oceanographic variables beneath the land fast ice in Kugmallit Bay, which suggests the onset of a spring melt occurring hundreds of km further south in the Mackenzie Valley. Estimates of sediment erosion rates in the Canadian Beaufort Sea (using the BEAST) helped us further understand the resuspension and transport of benthic organic material associated with sediments and aggregated particles. ... the large amount of allochthonous and autochthonous material supplied by the Mackenzie River under seasonal ice cover has significant consequences for carbon and sediment sequestration/export .... The re-design and calibration of BEAST [benthic environmental assessment sediment tool] ... has proven to be useful to quantify sediment erosion on the Beaufort Sea Shelf. ... The diversity of information obtained using BEAST (critical threshold, erosion rate, particle size distribution) provided much of the information required for assessing the rate of resuspension in particle cycling and benthic-pelagic coupling in Arctic shelf environments. Modelling of the Mackenzie River indicated that both water and sediment discharges are likely to increase under future climate scenarios. The peak flood season will likely occur earlier in the year. ... It is unknown to what extent increased river discharge would affect salinity and water temperature in the Mackenzie Delta. Both parameters would impact the formation of sea ice; in fact, decreased salinity might promote the formation of sea ice while increased temperature might demote it. Hydrodynamic modelling of the Beaufort Sea indicated that strong wave energy dissipation occurred along the Tuktoyaktuk Peninsula and Mackenzie Bay, suggesting that these areas are subject to strong coastal retreat. Under a scenario of reduced ice cover, the model predicted wave heights up to 20 cm higher than those observed throughout a typical storm. Such climate-induced changes (combined with storm surge and higher sea levels) would alter geomorphologic processes taking place at the coast (such as coastal retreat) and have dramatic impact on coastal communities. ... Vertical fluxes of particulate matter in the southeastern Beaufort Sea during Fall/Winter 2003-2004 originated from bottom resuspension on the Mackenzie Shelf as well as lateral transport within BNL/INLs [benthic nepheloid layer/intermediate nepheloid layer] across the shelf edge. ... The observed vertical particle mass flux generated by the BNL/INL events during Fall/Winter 2003-2004 was highest at the outer Franklin Bay site (CA-20; ~0.1 kg/m²). This indicated that Franklin Bay might be a depot-center of particulate matter in the southeastern Beaufort Sea due to an interplay between its coastal topography and local environmental conditions (such as winds and current dynamics ...). Vertical particle fluxes induced by BNL/INLs processes helped feed the pelago-benthic food web throughout 2003-2004 despite limited primary production during the darkness season. ... The mixing and downwelling sustained by thermohaline convection during ice formation was identified as a major driving force for shelf sediment resuspension and shelf-basin material flux. ... Trap collected zooplankton (TCZ) swimmers provide valuable information on the composition and seasonal behaviour of zooplankton communities .... Diagenesis in Amundsen Gulf sediment is not driven by sedimentation of terrestrial organic matter but by the settling of marine OM produced locally by primary producers. ... (Au)

D, E, G, A, B, H, F, I
Animal distribution; Benthos; Biological sampling; Bottom sediments; Carbon; Carbon cycling; Carbon dioxide; Chemical oceanography; Chlorophyll; Coast changes; Copepoda; Cores; Erosion; Iron; Isotopes; Manganese; Mathematical models; Nitrogen; Ocean currents; Ocean temperature; Ocean waves; Ocean-atmosphere interaction; Particulate organic matter; Phytoplankton; Plant growth; River discharges; Rivers; Salinity; Seasonal variations; Sediment transport; Sedimentation; Size; Spatial distribution; Storm surges; Storms; Stream flow; Strength; Submarine topography; Suspended solids; Temporal variations; Tides; Velocity; Water masses; Water pH; Winds; Zooplankton

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Arctic Red River, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Kugmallit Bay, N.W.T.; Kugmallit Valley, Canadian Beaufort Sea; Mackenzie Bay, N.W.T./Yukon; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea; Tuktoyaktuk Peninsula waters, N.W.T.


CO2 fluxes across the air-sea interface in the southeastern Beaufort Sea : ice-free period   /   Mucci, A.   Lansard, B.   Miller, L.A.   Papakyriakou, T.N.
(Journal of geophysical research, v.115, C04003, 2010, 14 p., ill., maps)
References.
ASTIS record 71808.
Languages: English
Web: doi:10.1029/2009JC005330
Libraries: ACU

Surface mixed layer CO2 fugacities (fCO2-sw) calculated from carbonate system parameters in the southeastern Beaufort Sea during the ice-free period ranged from 240 to 350 µatm in fall 2003 and from 175 to 515 µatm in summer 2004. The surface mixed layer remains mostly undersaturated with respect to atmospheric CO2 (378 µatm) and, therefore, acts as a potential CO2 sink throughout this period. Air-sea CO2 fluxes (FCO2) were first computed assuming ice-free conditions and ranged from -32.4 to +8.6 mmol m²/d in fall 2003 and summer 2004, respectively. Then we included a reduction factor to account for ice cover (ic) and we computed the resulting fluxes (FCO2-ic). In fall 2003, FCO2-ic ranged from -4.7 mmol m²/d in the relatively open water of the Cape Bathurst Polynya to -0.1 mmol m²/d in the southeastern Beaufort Sea, limited by the presence of the multiyear sea ice. In summer 2004, FCO2-ic ranged from -13.1 mmol m²/d on the western Mackenzie Shelf to +8.6 mmol m²/d at Cape Bathurst; the variability being ascribed to competing effects of vertical mixing, temperature variations, and possibly biological production. On average, a net sink of -2.3 ±3.5 mmol m²/d was estimated for the ice-free period over the study area. Nevertheless, the FCO2 displays strong variability due to ice coverage, freshwater input, and upwelling events. The potential responses (direction and intensity of potential feedbacks) of the carbon cycle in the study area to a changing Arctic climate are discussed. (Au)

D, E, G, F, H, I, J
Atmospheric humidity; Atmospheric temperature; Biological productivity; Carbon; Carbon dioxide; Carbonates; Chemical oceanography; Chlorophyll; Climate change; Environmental impacts; Ice cover; Melting; Meteorology; Ocean-atmosphere interaction; Oceanography; Polynyas; River discharges; Rivers; Runoff; Salinity; Sea ice; Sea water; Seasonal variations; Spatial distribution; Temporal variations; Water masses; Water pH; Weather stations; Winds

G07, G0815, G0812, G04
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Chukchi Sea; Greenland Sea; Hudson Bay; Laptevykh More; Mackenzie River, N.W.T.; Vostochno-Sibirskoye More


Late Pleistocene-Holocene marine geology of Nares Strait region : palaeoceanography from foraminifera and dinoflagellate cysts, sedimentology and stable isotopes   /   Mudie, P.J.   Rochon, A.   Prins, M.A.   Soenarjo, D.   Troelstra, S.R.   Levac, E.   Scott, D.B.   Roncaglia, L.   Kuijpers, A.
(Polarforschung, bd. 74, heft 1-3, 2006, p. 169-183, ill., maps)
References.
Includes German abstract.
ASTIS record 74721.
Languages: English
Web: http://epic.awi.de/Publications/Polarforsch2004_1-3_12.pdf
Web: doi:10013/epic.29931.d001
Libraries: ACU

A sediment-sampling program was carried out in the Nares Strait region during the Nares 2001 Expedition to obtain cores for high-resolution palaeoceanographic studies of late Pleistocene-Holocene climate change. Long cores (>4 m) were obtained from basins near Coburg Island, Jones Sound (Core 6, 75°35'N, 78°41'W), John Richardson Fiord off Kane Basin (Core 39, 80°09.6'N, 70°50.3'W), and in northeastern Hall Basin (Core 79, 81°28.3'N, 62°16.4'W). Short cores and grab samples were taken on shelves east and west of northern Smith Sound and in Kennedy Channel. Detailed studies of sediment texture, stable isotopes, microfossils and palynomorphs were made on the longest cores from Jones Sound and Hall Basin at the southern and northern ends of the Nares Strait region. Core 6 is from a water depth of 561 m off Devon Island where the sea-ice cover (SIC) is presently >5/10 for nine months per year. Sediment is a bioturbated organic-rich clayey mud, with an age of 6315 ±60 years BP near the base. The mud has a mean grain size ranging ~3-4.5 µm. Peaks of sand and granules appear at about 3.4 ka BP and increase upward, suggesting greater influx of ice-rafted detritus over the past 2000 years. Sedimentation rates of 16-19 cm/century allow for decadal-scale palaeoceanographic studies. Abundant foraminifers and common small bivalve shells are present. Benthic faunas are diverse, with common calcareous and agglutinated species, predominantly Reophax arctica and Textularia torquata. In contrast, planktonic foraminifera are sparse and have heavy delta 18O isotopic values (~3-5‰), indicating that this fauna lives in the very cold (-1.5 °C), saline (33.5) water below the pycnocline at ~125 m. Large-scale (~2‰) oscillations in delta 18O values occur at intervals of about 2000 years. Palynomorphs include abundant dinoflagellate cysts, prasinophytes and foraminiferal linings; pollen and spores are also common. Palaeoceanographic reconstructions from dinocyst assemblages show that from ~6.5 to 3.3 ka BP, there were large oscillations in summer sea surface temperature (SST) from 3 °C cooler than now to 6 °C warmer, and that variations in SIC ranged from two months more to four months less of heavy ice compared to now. In Hall Basin, Core 79 is from a water depth of 550 m near the Petermann Glacier where SST is -1.4 °C but the thermocline is shallow and the bottom water below 200 m is warmer (-0.4 to 0 °C) than in Jones Sound. SIC is presently about 8/10 for eleven months per year. Core 79 consists of dominantly clayey calcareous mud, with an upper unit of brown silty mud and scattered sand and has an age of more than 8.4 ka BP at the base. This overlies ~4 m of brown and gray coarsely banded mud with some finely laminated intervals and an age of 14.07 ka BP at the top. Shear strength is low (<8-12 KN/m²) and shows no compaction by grounded ice. Planktonic and benthic foraminafera occur throughout and their delta 18O records are consistently lighter (3-4‰) than in Core 6, reflecting the warmer water below 50 m. The delta 18O signals are also less variable, suggesting smaller climatic oscillations on the polar margin than in Jones Sound. The diverse benthic assemblages are dominated by the calcareous species Buliminella hensonii, Elphidium clavatum and Islandiella teretis. The banded sediment has low numbers of benthic foraminifera dominated by Cassidulina reniforme and Elphidium clavatum, with relatively high percentages of Buliminella hensoni, Islandiella teretis and some Stetsonia arctica indicating Arctic Ocean slope to deep-water conditions. The banded sediment represents deposition under pack ice or a floating ice shelf and there is no evidence of grounded ice in eastern Hall Basin during at least the past 14 ka BP. (Au)

B, H, I, G, D, F, E, J
Algae; Benthos; Bottom sediments; Clay; Climate change; Cone Penetrometer Test; Continental shelves; Cores; Density; Dinoflagellata; Effects of climate on ice; Foraminifera; Glacial epoch; Glaciers; Ice cover; Isotopes; Lamellibranchiata; Magnetic properties; Marine geology; Mollusks; Ocean temperature; Oxygen-18; Palaeohydrology; Palaeontology; Palynology; Palynomorphs; Plankton; Pleistocene epoch; Radiocarbon dating; Recent epoch; Salinity; Sand; Sea ice; Sediment transport; Sedimentation; Silt; Size; Spatial distribution; Stratigraphy; Strength; Temporal variations

G09, G0815
Coburg Island waters, Nunavut; Hall Basin, Greenland/Nunavut; John Richardson Bay, Nunavut; Jones Sound, Nunavut; Kennedy Channel, Nunavut; Makinson Inlet, Nunavut; Nares Strait, Greenland/Nunavut; Smith Sound, Greenland/Nunavut


Scale dependent forcing on ice algae dynamics : observations and modelling   /   Mundy, C.-J.   Barber, D. [Supervisor]   Michel, C. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2007.
xvi, 232 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR26301)
ISBN 978-0-494-26301-3
References.
Thesis (Ph.D.) - University of Manitoba, Winnipeg, Man., 2007.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74977.
Languages: English
Libraries: OONL

Sea ice algae play a critical role as the first available food source in ice-covered polar oceans. Changes in the thermal, physical and optical properties of the snow-sea ice system and feedbacks between various temporal and spatial scales affect accumulation of algae at the sea ice bottom and are the focus of this dissertation. The principle objective is to determine the importance of various characteristics and scales of physical processes on the accumulation and loss of bottom ice algae during the spring season. Field data used in the dissertation come from two spring field seasons undertaken in 2002 and 2003 near Resolute Bay, Nunavut, on landfast first-year sea ice. Results show that transmitted light, ice temperature and bottom ice structure are largely dependent on the spatial distribution and highly variable depth history of the overlying snow cover, which induces variability on ice algae biomass. Furthermore, the physical processes controlling the magnitude of biomass can differ based on snow depth from a thermal melt-off effect under thin snow to light limitation and thermal insulation under thick. It is also noted that destructive point sampling of the sea ice for algal biomass estimation limits a direct analysis of the principle objective. Therefore, algae optical absorption properties are used to develop methods for remote estimation of ice algal biomass. A coupled ice algae growth model is also employed to further examine the principle objective. Improvements were made to the model using detailed measurements of snow, sea ice and ice algae thermal and optical properties. The results supported the conclusions drawn from observations; however, simulations also demonstrated that the thermal and optical factors are not exclusive in their effects on algal accumulation and loss based on snow depth. The model was also found to be very sensitive to variability in light attenuation and the ice warming rate. This dissertation highlights the importance of snow cover history and distribution on the sea ice system operating below. Furthermore, results emphasize the sensitivity of the bottom ice algae ecosystem to Arctic climate change through potential shifts in snow depth distribution and thermophysical changes induced by atmospheric or oceanic changes in temperature. (Au)

H, G, F, E, D, J
Albedo; Algae; Atmospheric humidity; Atmospheric temperature; Biomass; Blowing snow; Chlorophyll; Clouds; Cores; Crystals; Density; Fast ice; Formation; Growth; Heat transmission; Light; Mathematical models; Melting; Ocean currents; Ocean-atmosphere interaction; Optical properties; Photography; Physical properties; Plant growth; Radiation budgets; Salinity; Sea ice; Sea ice ecology; Size; Snow; Snow cover; Snow stratigraphy; Snowdrifts; Solar radiation; Spatial distribution; Temperature; Temporal variations; Thermal properties; Thermodynamics; Theses; Thickness; Velocity; Winds

G0815
Fournier Channel, Nunavut; McDougall Sound, Nunavut


Variability of snow and ice thermal, physical and optical properties pertinent to sea ice algae biomass during spring   /   Mundy, C.J.   Barber, D.G.   Michel, C.
(Journal of marine systems, v. 58, no. 3-4, Dec. 2005, p. 107-120, ill., maps)
References.
ASTIS record 59691.
Languages: English
Web: doi:10.1016/j.jmarsys.2005.07.003
Libraries: ACU

Changes in the thermal, physical and optical properties of the snow-sea ice system and feedbacks between various temporal and spatial scales affect accumulation of microalgae at the sea ice bottom and are the focus of this research. During the spring transition period, May 4 to June 9, 2002, we closely monitored atmospheric conditions and properties of the snow-sea ice system, including thermal, physical and optical properties of the snow cover (e.g., temperature, grain size, light attenuation), ice thickness and salinity, and biomass of bottom ice algae. Results show that snowdrift size averaged 31.2 by 10.6 m with a depth range of 2 to 45 cm. Snowpacks also varied in age, distinguished by coincident peaks of snow salinity and grain size and a lower PAR extinction coefficient. Spatial variability of the snowpack was superimposed by temporal variability associated with seasonal snow-ice melt and wind redistribution of snow. Maximum biomass of ice algae was observed under intermediate snow covers. Under thin snow covers, algae biomass declined steadily coincident with seasonal warming and desalination of the ice cover. Under thick snow covers, algae biomass was negatively correlated with snow depth. These results suggest that thin snow covers were associated with a thermal effect causing sloughing of algae, whereas under deep snow, algae were still light limited and thermally insulated from the warming atmosphere. Our results highlight the importance of snow cover history on the sea ice system operating below. Furthermore, in the context of current climate change scenarios, shifts in snow depth would result in decreases of ice algae biomass. (Au)

F, G, H, E, J
Albedo; Algae; Biomass; Blowing snow; Climate change; Heat transmission; Ocean-atmosphere interaction; Physical properties; Salinity; Sea ice; Sea ice ecology; Seasonal variations; Snow; Snow cover; Surface properties; Temporal variations; Thermal properties; Thickness

G0815
McDougall Sound, Nunavut


Linking ice structure and microscale variability of algal biomass in Arctic first-year sea ice using an in situ photographic technique   /   Mundy, C.J.   Barber, D.G.   Michel, C.   Marsden, R.F.
(Polar biology, v. 30, no. 9, Aug. 2007, p.1099-1114, ill.)
References.
ASTIS record 63278.
Languages: English
Web: doi:10.1007/s00300-007-0267-1
Libraries: ACU

Microscale photographs were taken of the ice bottom to examine linkages of algal chlorophyll a (chl a) biomass distribution with bottom ice features in thick Arctic first-year sea ice during a spring field program which took place from May 5 to 21, 2003. The photographic technique developed in this paper has resulted in the first in situ observations of microscale variability in bottom ice algae distribution in Arctic first-year sea ice in relation to ice morphology. Observations of brine channel diameter (1.65-2.68 mm) and number density (5.33-10.35 per 100 cm²) showed that the number of these channels at the bottom of thick first-year sea ice may be greater than previously measured on extracted ice samples. A variogram analysis showed that over areas of low chl a biomass (<=20.7 mg chl a/m²), patchiness in bottom ice chl a biomass was at the scale of brine layer spacing and small brine channels (~1-3 mm). Over areas of high chl a biomass (>=34.6 mg chl a/m²), patchiness in biomass was related to the spacing of larger brine channels on the ice bottom (~10-26 mm). Brine layers and channels are thought to provide microscale maxima of light, nutrient replenishment and space availability which would explain the small scale patchiness over areas of low algal biomass. However, ice melt and erosion near brine channels may play a more important role in areas with high algal biomass and low snow cover. (Au)

H, G, J, E, F, D
Algae; Atmospheric temperature; Biomass; Chlorophyll; Cores; Crystals; Fast ice; Light; Logistics; Measurement; Microbial ecology; Ocean currents; Optical properties; Photography; Physical properties; Plant distribution; Plant nutrition; Salinity; Sea ice; Sea ice ecology; Snow; Surface temperature; Temperature; Temporal variations; Thickness; Velocity

G0815
Resolute Passage, Nunavut


Influence of snow cover and algae on the spectral dependence of transmitted irradiance through Arctic landfast first-year sea ice   /   Mundy, C.J.   Ehn, J.K.   Barber, D.G.   Michel, C.
(Journal of geophysical research, v.112, no. 3, C03007, Mar. 2007, 10 p., ill., maps)
References.
ASTIS record 63280.
Languages: English
Web: doi:10.1029/2006JC003683
Libraries: ACU

Extensive spatial and temporal observations of sea ice algae remain limited due in part to current destructive and time intensive sampling techniques. In this paper we examine the influence of snow cover and ice algal biomass on the spectral dependence of photosynthetically available radiation transmitted through the snow-ice matrix using a data set collected in Resolute Passage, Canada, from 3 to 21 May 2003. The relationships between a normalized difference index (NDI) of transmitted irradiance with ice algal biomass and with snow cover provided a means to examine and compare observational and modeled data. In contrast to the dominant scattering properties of snow, absorption largely controls the spectral diffuse attenuation coefficient of algae. Our results show that snow has little effect on the distribution of transmitted spectral irradiance at wavelengths between 400 and 550 nm, whereas algae have a strong absorption peak near 440 nm that dominates changes in spectral transmission across this wavelength range. Up to 89% of the total variation in algae biomass was accounted for with a single NDI wavelength combination. Therefore the blue wavelength peak in algal spectral absorption lends particularly well to the remote estimation of algae biomass using transmitted irradiance. Deviations between observed and modeled data highlight the need for improvements to model inputs and therefore more detailed observations of processes controlling snow, ice, and algae in situ optical properties. (Au)

F, G, H, E, J
Albedo; Algae; Biomass; Chlorophyll; Cores; Fast ice; Fluorometry; Light; Mathematical models; Measurement; Optical properties; Physical properties; Salinity; Sea ice; Snow; Snow stratigraphy; Spectroscopy; Thickness; Water content of snow

G0815
Resolute Passage, Nunavut


Temporal and spatial evolution of the mixed layer in the southern Beaufort sea and the Amundsen Gulf   /   Nahavandian Esfahani, S.   Gratton, Y. [Supervisor]   Prieur, L. [Supervisor]
Saint-Foy, Québec : Université du Québec Institut National de la Recherche Scientifique, 2014.
lvi, 167 p. : ill., maps ; 28 cm.
Thesis (Ph.D.).
References.
Appendices.
Chapter 0 is in French and Chapters 1 to 6 are in English.
ASTIS record 81664.
Languages: English or French
Web: http://espace.inrs.ca/id/eprint/2617
Web: http://espace.inrs.ca/2617/1/NahavandianEsfahaniSomayeh.pdf
Libraries: OONL

The mixed layer, which is the oceanic surface layer with constant physical properties due to mixing, plays an important role in contaminant and biological studies. This thesis is an attempt to further enhance our knowledge of the Arctic Ocean through a study of the characteristics of the mixed layer in southern Beaufort Sea and Amundsen Gulf. The Mixed Layer Depth was estimated using five different methods and it was found that the most appropriate one for our study region was a modified version of the Holte and Talley (2009) algorithm. Our study is based on numerous recent, unique data sets gathered in southern Beaufort Sea during the winters of 2003-2004 and 2007-2008, as well as during the summers and falls of 2002, 2003, 2004, 2005, 2006, 2007, 2008 and 2009. Its unique feature is the two complete years of data obtained during 2003-2004 and 2007-2008. The temporal evolution and the spatial distribution of the Mixed Layer Depths was studied in four subregions, further subdivided into inshore (depths < 200 m) and offshore (depths > 200 m) subregions. It was shown that the Mixed Layer Depth was generally deeper offshore during the fall, winter and spring, while in summer they are comparable in both regions. The Mixed Layer Depth was significantly deeper during 2007-2008 compared to all the other years due to a strong upwelling event in the fall of 2007. Differences between the winters of 2004 and 2008 are also due to the different ice covers in the study regions: landfast ice in 2003-2004 versus drifting ice floes in 2007- 2008. Furthermore, the Mixed Layer Depths were the shallowest during the summer and afterwards they gradually deepened until they reached their maximum thickness in April. Probability distribution functions showed that the distribution are mostly of the one "hump" variety, meaning that there was a single, preferred Mixed Layer Depth range for each region and season. The originality of this thesis lies in the approach we used to study the mixed layer evolution at a fixed station in Franklin Bay, Amundsen Gulf. We analyzed the mass budget of the mixed layer between December 2003 and June 2004, based on the heat budget approach of Emery (1976) and modified by Prieur et al. (2010). The only assumption needed was that there was no non-divergent lateral advection. The beauty of the approach is that it needs only vertical density profiles, from moored or drifting instruments. This method also enables us to include the important effect of the vertical advection at the base of the mixed layer and produces an estimate of the surface ice growth rates. The analysis of four months of under ice Chl a concentrations has shown that blooming starts just after the mixed layer has attained its largest thickness in the spring, and reaches its maximum concentrations about one month later. (Au)

D, E, J
Biological productivity; Chlorophyll; Climate change; Density; Heat budgets; Heat transmission; Ice cover; Marine ecology; Marine pollution; Mathematical models; Ocean temperature; Ocean-atmosphere interaction; Oceanographic instruments; Oceanography; Salinity; Sea water; Seasonal variations; Spatial distribution; Temporal variations; Theses; Water masses

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Arctic Islands waters; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Development of indicators for Arctic marine biodiversity monitoring in Canada = Élaboration d'indicateurs pour la surveillance de la biodiversité marine dans l'Arctique canadien   /   Nelson, R.J.
[Ottawa] : Fisheries and Oceans Canada, National Capital Region, 2012.
iv, 35 p. : maps ; 28 cm.
(Research document - Canadian Science Advisory Secretariat, 2012/123)
Indexed a PDF file from the Web.
References.
French abstract and title provided.
ASTIS record 77565.
Languages: English
Web: http://www.dfo-mpo.gc.ca/Csas-sccs/publications/resdocs-docrech/2012/2012_123-eng.pdf

Biodiversity underpins stable and productive marine ecosystems which provide a range of goods and services. Monitoring of the status and trends of marine biodiversity in the Arctic is needed to allow for informed decision making around issues of sustainable resource use, environmental protection, and adaptation to changing conditions in the North. The development of such an arctic marine biodiversity monitoring strategy in Canada builds on the Circumpolar Biodiversity Monitoring Plan - Marine Plan (CBMP-MP) which calls for an indicator-based approach. It is necessary to tailor the indicators presented in the CBMP-MP to those that are relevant and logistically feasible in Canada. To this end, biodiversity indicators based on historical data and ongoing research are recommended for microbes, zooplankton, fishes, sympagic and benthic organisms as well as marine mammals. These indicators will be useful for biodiversity monitoring in Canadian marine arctic waters and will serve as Canada's position on indicators for the CBMP-MP. (Au)

I, J, H, G, D, E
Adaptation (Biology); Algae; Animal distribution; Animal population; Animal taxonomy; Archaea; Bacteria; Benthos; Biological sampling; Biomass; Chemical oceanography; Climate change; Effects monitoring; Environmental impacts; Fishes; Genetics; Ice cover; Light; Marine biology; Marine ecology; Marine mammals; Microbial ecology; Phytoplankton; Primary production (Biology); Protozoa; Remote sensing; Sea ice; Sea ice ecology; Seasonal variations; Temporal variations; Viruses; Water masses; Wildlife habitat; Zooplankton

G081, G02, G07, G09, G0814
Arctic waters; Baffin Bay-Davis Strait; Canadian Arctic waters; Canadian Beaufort Sea; Hudson Bay; Hudson Strait, Nunavut/Québec; Lancaster Sound, Nunavut; North Water Polynya, Baffin Bay


Picobiliphytes : a marine picoplanktonic algal group with unknown affinities to other eukaryotes   /   Not, F.   Valentin, K.   Romari, K.   Lovejoy, C.   Massana, R.   Töbe, K.   Vaulot, D.   Medlin, L.K.
(Science, v.315, no.5809, 12 Jan. 2007, p. 253-255, ill.)
References.
Supporting material available online.
ASTIS record 74719.
Languages: English
Web: doi:10.1126/science.1136264
Libraries: ACU

Environmental sequencing has revealed unimagined diversity among eukaryotic picoplankton. A distinct picoplanktonic algal group, initially detected from 18S ribosomal DNA (rDNA) sequences, was hybridized with rRNA lambda-targeted (rRNA-targeted) probes, detected by tyramide signal amplification-fluorescent in situ hybridization, and showed an organelle-like body with orange fluorescence indicative of phycobilins. Using this fluorescence signal, cells were sorted by flow cytometry and probed. Hybridized cells contained a 4',6'-diamidino-2-phenylindole-stained organelle resembling a plastid with a nucleomorph. This suggests that they may be secondary endosymbiotic algae. Pending the isolation of living cells and their formal description, these algae have been termed picobiliphytes. (Au)

H, I, J, D
Algae; Fluorometry; Genetics; Marine biology; Microorganisms; Phytoplankton; Plant anatomy; Plant distribution; Plant taxonomy; Proteins; Size

G02
Arctic waters; English Channel; Mediterranean Sea; North Sea


CASES2003, Leg 3 (0305) CCGS Amundsen cruise & preliminary data report 26 November 2003 to 06 January 2004   /   Nozais, C. [Editor]
Québec, Québec : Université Laval, 2004.
[36] p. : ill. ; 28 cm.
Appendix.
Cover title.
Indexed a PDF file from the Web.
References.
ASTIS record 74423.
Languages: English
Web: http://www.cases.quebec-ocean.ulaval.ca/CASES0304_leg3_cruise_report.pdf

This report describes the scientific studies carried out in Leg 3 of the CCGS Amundsen cruise, which included: 1. Atmospheric & Sea Ice Forcing of Coastal Circulation on the Mackenzie Shelf; 1.1 Rosette and CTD activities; 2. Ice-atmosphere Interactions and Biological Linkages; 2.1 Cloud Physics and Synoptic Climatology; 2.2 Physical and electromagnetic properties of snow over sea ice; 2.3 Gas Fluxes; 3. Light, Nutrients, Primary and Export Production in ice-free waters; 3.1 Nutrients and phytoplankton dynamics in Franklin Bay; 3.2 Microcosms studies on phytoplankton growth during winter in Franklin Bay; 4. Microbial Communities and Heterotrophy; 4.1 Microbial production and community structure; 5. Pelagic Food Web: Structure, Function and Contaminants; 5.1 Memorial University; 5.2 NIPR, Japan; 5.3 U. Laval; 6. Organic and Inorganic Fluxes; 6.1 Sediment Geochemistry. (ASTIS)

D, G, E, B, H, I, J, L
Amundsen (Ship); Arctic cod; Atmospheric chemistry; Bacteria; Benthos; Biological sampling; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chemical oceanography; Climate change; Clouds; Copepoda; Cores; Electrical properties; Equipment and supplies; Fishes; Geochemistry; Hydrography; Ice cover; Instruments; Light; Marine ecology; Marine mammals; Measurement; Meteorology; Microbial ecology; Nitrogen; Ocean-atmosphere interaction; Physical properties; Phytoplankton; Primary production (Biology); Radar; Sea ice; Seasonal variations; Snow; Suspended solids; Synoptic climatology; Temporal variations; Traditional knowledge; Viruses; Water masses; Zooplankton

G07, G0812, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon


Particle fluxes and geochemistry on the Canadian Beaufort Shelf : implications for sediment transport and deposition   /   O'Brien, M.C.   Macdonald, R.W.   Melling, H.   Isek, K.
(Continental shelf research, v. 26, no. 1, Jan. 2006, p. 41-81, ill., maps)
(NOGAP project no. B.06 : Beaufort Sea oceanography)
References.
ASTIS record 63282.
Languages: English
Web: doi:10.1016/j.csr.2005.09.007
Libraries: ACU

Biogeochemical data from four sequential sediment traps deployed for one full year (April 1987-March 1988) at the shelf edge (200 m isobath) of the Canadian Beaufort Sea are presented. In addition, multi-traps and Kenney traps, which collect material suspended near the bottom, provided data from the inner shelf for short intervals in spring and summer. A novel aspect of this work is the discrimination of biogenic and terrigenous contributions to the total carbon using a relationship between terrigenous carbon and aluminum (Al). The vertical flux in the Beaufort Sea derives primarily from three sources: marine biological production, the Mackenzie River Plume, and coastal and seabed erosion. The material trapped at all shelf edge sites was predominantly biogenic and the seasonal fluxes of both biogenic and terrigenous matter varied with geographical location. In open-water conditions, deposition of terrigenous material can be attributed at various times and places to (1) transport by the Mackenzie Plume to the shelf edge during freshet; (2) resuspension of sediment during north-westerly gales; and (3) erosion of steep coastlines during south-easterly gales followed by northward transport. On the west side of the shelf, the biogenic and terrigenous fluxes were highest in summer and were primarily influenced by the Mackenzie River freshet, increased solar flux, available nutrients, sea ice break-up, and water column stability. On the east side of the shelf, biogenic and terrigenous fluxes were highest in the fall and the most important controlling factors were the extensive open water, intense resuspension events accompanying storms from the northwest, and the flow of the fresh, warm, turbid waters of Mackenzie River to the northeast. There was strong evidence of sediment transport in mid-water and bottom layers, but the mechanisms involved cannot be inferred from this study. Stable isotopes of carbon and nitrogen, C/N ratios, biogenic silica, and chlorophyll a measurements help to distinguish between marine autotrophic production and heterotrophic production, of which the latter appears to dominate in the fall and continue beneath the ice into the polar night. Al and iron correlate strongly and are primarily associated with the terrigenous fraction whereas calcium and phosphorus have both terrestrial and biogenic associations. (Au)

D, F, E, B, G, A, H, I, J
Algae; Aluminum; Atmospheric temperature; Bacteria; Biological productivity; Calcium; Carbon; Chlorophyll; Coast changes; Continental shelves; Data buoys; Erosion; Fast ice; Geochemistry; Ice cover; Iron; Isotopes; Light; Logistics; Measurement; Nitrogen; Ocean currents; Ocean waves; Phosphorus; Phytoplankton; Primary production (Biology); River discharges; Salinity; Seasonal variations; Sediment transport; Sedimentation; Silica; Solar radiation; Spatial distribution; Storm surges; Storms; Stream flow; Suspended solids; Water masses; Winds; Zooplankton

G07, G0812, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Kugmallit Bay, N.W.T.; Liverpool Bay, N.W.T.; Mackenzie Bay, N.W.T./Yukon; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.


Photochemical production of hydrogen peroxide and methylhydroperoxide in coastal waters   /   O'Sullivan, D.W.   Neale, P.J.   Coffin, R.B.   Boyd, T.J.   Osburn, C.L.
(Special issue in honor of Dana R. Kester / Edited by R.H. Byrne. Marine chemistry, v. 97, no. 1-2, Oct. 2005, p. 14-33, ill.)
References.
ASTIS record 65879.
Languages: English
Web: doi:10.1016/j.marchem.2005.04.003
Libraries: ACU

Hydrogen peroxide (H2O2) has been observed in significant concentrations in many natural waters. Because hydrogen peroxide can act as an oxidant and reductant, it participates in an extensive suite of reactions in surface waters. Hydrogen peroxide is produced as a secondary photochemical product of chromophoric dissolved organic matter (CDOM) photolysis. Apparent quantum yields for the photochemical production of hydrogen peroxide were determined in laboratory irradiations of filtered surface waters from several locations in the Chesapeake Bay and in Arctic coastal waters with varying levels of CDOM. The apparent quantum yield for H2O2 decreases by about an order of magnitude from 280 nm to 500 nm, and the majority of H2O2 production occurs at wavelengths less than 340 nm. The apparent quantum yield for H2O2 production at 290 nm ranged from 4.2×10**-4 to 2.1×10**-6 mol H2O2/mol/photons from freshwater to marine waters. A linear relationship was found between the production of H2O2 and change in CDOM absorbance characterized as photobleaching (loss of absorbance). No significant relationship was observed between DOC concentration and peroxide production. Methylhydroperoxide (CH3O2H) was the only short chain peroxide produced during the irradiations, and its production is at least an order magnitude less than that of hydrogen peroxide. Peroxide production was greatest in waters containing significant amounts of terrigenous C in the form of humic substances. Surface waters whose synchronous fluorescence spectra indicated the presence of polyaromatic and/or extensive conjugated compounds exhibited the greatest peroxide production. CDOM photobleaching is not significantly linked to apparent quantum yields for peroxide production. (Au)

D, F
Carbon; Chemical oceanography; Chemical properties; Chromatography; Colored dissolved organic matter; Dissolved organic carbon; Estuaries; Fluorometry; Hydrogen peroxide; Optical properties; Rivers; Runoff; Salinity; Sea water; Solar radiation; Spectroscopy

G07, G11, G05
California waters; Canadian Beaufort Sea; Maryland; North Atlantic Ocean; Virginia


The use of wet chemical oxidation with high-amplification isotope ratio mass spectrometry (WCO-IRMS) to measure stable isotope values of dissolved organic carbon in seawater   /   Osburn, C.L.   St-Jean, G.
(Limnology and oceanography, methods, v. 5, Oct. 2007, p. 296-308, ill.)
References.
ASTIS record 65883.
Languages: English
Web: http://www.aslo.org/lomethods/locked/2007/0296.pdf
Web: doi:10.4319/lom.2007.5.296
Libraries: ACU

Few measurements of the carbon stable isotope value (delta 13C) of marine dissolved organic carbon (DOC), the largest pool of reduced carbon in the ocean, have been made because of analytical obstacles due to the interference of halides and the low amount of DOC in seawater. By using concentrated persulfate in a wet chemical oxidation organic carbon analyzer coupled to an isotope ratio mass spectrometry (WCO-IRMS) the analytical obstacles are overcome. Key to this method is reducing the persulfate blank and increasing the IRMS signal with larger amplifier gain resistors. After these simple modifications, a 2 mL sample provides enough signal to make precise measurements of DOC concentration and delta 13C value on up to 15 samples per day. Sodium persulfate (1.68 mol/L) is cleaned by pre-heating and sparging with ultrahigh purity helium. In the WCO analyzer, 6 mL cleaned persulfate is added to 2 mL sample at 98°C for 8.5 min to completely oxidize DOC to CO2. After quantitative measurement by nondispersive IR, the gases contained in the exhaust are swept through a cleanup reactor, separated by a GC column and introduced to the IRMS for delta 13C measurement. Complete recovery of the DOC and delta 13C values was confirmed with two DOC standards added individually to seawater. IRMS precision was confirmed by measuring a range of sea water samples. On several coastal water samples measured using this system, delta 13C-DOC values ranging from -22‰ to -25‰. These results were consistent with published reports of seawater delta 13C-DOC using other methods. (Au)

D
Carbon; Chemistry; Chromatography; Dissolved organic carbon; Equipment and supplies; Instruments; Isotopes; Logistics; Mass spectrometry; Measurement; Salinity; Sea water

G07, G0815, G11
Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mexico, Gulf of; North Atlantic Ocean; Sachs Harbour, N.W.T.


Photoreactivity of chromophoric dissolved organic matter transported by the Mackenzie River to the Beaufort Sea   /   Osburn, C.L.   Retamal, L.   Vincent, W.F.
(Marine chemistry, v.115, no. 1-2, June 2009, p. 10-20, ill., map)
References.
ASTIS record 74360.
Languages: English
Web: doi:10.1016/j.marchem.2009.05.003
Libraries: ACU

The photoreactivity of chromophoric dissolved organic matter (CDOM) transported to Arctic shelf environments by rivers has only recently been studied and its quantitative role in Arctic shelf biogeochemistry has received little attention. Sunlight exposure experiments were performed on CDOM collected over a three year period (2002 to 2004) from river, estuary, shelf, and gulf regions of the Western Canadian Arctic. Decreases in CDOM absorption, synchronous fluorescence (SF), and dissolved organic carbon (DOC) concentration were followed after 3 days of exposure, and in two experiments, six optical cutoff filters were used to incrementally remove ultraviolet radiation incident on the samples. Apparent quantum yields for CDOM photobleaching (AQYble) and for DOC photomineralization (AQYmin) were computed, as were two AQY spectra (phi ble and phi min) for the Mackenzie River and a sample from the Mackenzie Shelf. The photoreactivity of Mackenzie River CDOM was highest after break-up and peak discharge and lowest in late summer. The half-lives of CDOM and DOC were estimated at 3.7 days and 4.8 days, respectively, when Mackenzie River water was exposed to full sunlight. Photobleaching of Mackenzie River CDOM fluorescence after most UV-B wavelengths were removed increased the correlation between the river and offshore waters in the Beaufort Sea. When light attenuation from particle- and CDOM-rich river water was considered for the Mackenzie Shelf, our photodegradation models estimated around 10% loss of absorption and <1% DOC loss, suggesting that sunlight exposure does not substantially degrade CDOM on Arctic shelves. (Au)

D, F, G, E, H
Bacteria; Breakup; Chemical oceanography; Chemical properties; Climate change; Colored dissolved organic matter; Continental shelves; Dissolved organic carbon; Estuaries; Fluorometry; Hydrology; Mathematical models; Optical properties; Photosynthesis; River discharges; River ice; Rivers; Seasonal variations; Sediment transport; Stamukhi; Stream flow; Temporal variations; Ultraviolet radiation

G0812, G07
Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Mackenzie River, N.W.T.; Middle Channel (Mackenzie River), N.W.T.


Seasonal changes in nauplii and adults of Calanus hyperboreus (Copepoda) captured in sediment traps, Amundsen Gulf, Canadian Arctic   /   Ota, Y.   Hattori, H.   Makabe, R.   Sampei, M.   Tanimura, A.   Sasaki, H.
(Polar science, v. 2, no. 3, 25 Sept. 2008, p. 215-222, ill., maps)
References.
ASTIS record 65875.
Languages: English
Web: doi:10.1016/j.polar.2008.08.002
Libraries: ACU

Arctic copepods were collected using time-series sediment traps in the Amundsen Gulf, Canadian Arctic, as part of the CASES (Canadian Arctic Shelf Exchange Study) program. Four sediment traps were deployed at three stations (200 m depth for CA15, 200 and 400 m depths for CA18, and 200 m depth for CA20) from October 2003 to July 2004. We collected many copepod nauplii ranging in body length from 155 to 811 µm, among which nauplii (mostly N1-2) of Calanus with a size of ~190 µm apparently increased in abundance from February to mid-March. Mature-stage adult females (AF) of Calanus hyperboreus were collected in the traps from February to March, and adult males of C. hyperboreus appeared from November to December at all stations. The likely spawning period of these AF coincided with the occurrence period of ~190 µm-sized nauplii. This finding suggests that these nauplii were derived from C. hyperboreus and that their breeding began at the beginning of November or December at the latest, continuing through April in the Amundsen Gulf. (Au)

I, J, H, D
Animal distribution; Animal food; Animal population; Animal reproduction; Biological sampling; Copepoda; Gender differences; Invertebrate larvae; Lipids; Marine ecology; Ocean temperature; Phytoplankton; Salinity; Seasonal variations; Size; Zooplankton

G0815
Amundsen Gulf, N.W.T.


A mass balance inventory of mercury in the Arctic Ocean   /   Outridge, P.M.   Macdonald, R.W.   Wang, F.   Stern, G.A.
(Environmental chemistry, v. 5, no. 2, 2008, p. 89-111, ill., maps)
References.
ASTIS record 66285.
Languages: English
Web: doi:10.1071/EN08002
Libraries: ACU

The present mercury (Hg) mass balance was developed to gain insights into the sources, sinks and processes regulating biological Hg trends in the Arctic Ocean. Annual total Hg inputs (mainly wet deposition, coastal erosion, seawater import, and 'excess' deposition due to atmospheric Hg depletion events) are nearly in balance with outputs (mainly shelf sedimentation and seawater export), with a net 0.3%/year increase in total mass. Marine biota represent a small fraction of the ocean's existing total Hg and methyl-Hg (MeHg) inventories. The inertia associated with these large non-biological reservoirs means that 'bottom-up' processes (control of bioavailable Hg concentrations by mass inputs or Hg speciation) are probably incapable of explaining recent biotic Hg trends, contrary to prevailing opinion. Instead, varying rates of bioaccumulation and trophic transfer from the abiotic MeHg reservoir may be key, and are susceptible to ecological, climatic and biogeochemical influences. Deep and sustained cuts to global anthropogenic Hg emissions are required to return biotic Hg levels to their natural state. However, because of mass inertia and the less dominant role of atmospheric inputs, the decline of seawater and biotic Hg concentrations in the Arctic Ocean will be more gradual than the rate of emission reduction and slower than in other oceans and freshwaters. Climate warming has likely already influenced Arctic Hg dynamics, with shrinking sea-ice cover one of the defining variables. Future warming will probably force more Hg out of the ocean's euphotic zone through greater evasion to air and faster Hg sedimentation driven by higher primary productivity; these losses will be countered by enhanced inputs from coastal erosion and rivers. (Au)

J, I, D, N, E, F, H, B, G, A
Animal health; Atmospheric circulation; Biological sampling; Blood; Chemical oceanography; Climate change; Coasts; Effects monitoring; Erosion; Fishes; Food; Food chain; Geochemistry; Health; Hydrology; Inuit; Marine mammals; Marine pollution; Mass balance; Mathematical models; Measurement; Mercury; Movement; Ocean currents; Ocean-atmosphere interaction; Primary production (Biology); Rivers; Runoff; Sea ice; Sea water; Seasonal variations; Sediment transport; Sedimentation; Snow; Subsistence; Temporal variations; Toxicity; Trace elements; Zooplankton

G03, G081, G10, G02
Alert, Nunavut; Arctic Ocean; Arctic waters; Baffin Bay-Davis Strait; Barrow, Alaska; Canadian Arctic; Churchill, Manitoba; Greenland; Lancaster Sound, Nunavut; Mackenzie River, N.W.T.


Wintertime measurements of pCO2 in Arctic landfast sea ice   /   Owens, O.C.   Papakyriakou, T.N. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2008.
xv, 111, xvi, [55] p. : ill., maps ; 28 cm.
References.
Thesis (M.Sc.) - University of Manitoba, Winnipeg, Man., 2008.
Indexed a PDF file from the Web.
ASTIS record 65291.
Languages: English
Web: http://mspace.lib.umanitoba.ca/bitstream/1993/3093/1/Owen%20Owens.pdf

Previous assumptions were that gas is not transferred between the atmosphere and the ocean through sea ice, leaving the frozen Arctic out of global and regional carbon cycle models. Recent work has shown two features of first year sea ice that, when combined, detail a method by which gas exchange can occur through ice. First, carbon fluxes over sea ice surfaces in both directions have been measured. Second, sea ice brine has an elevated capacity over seawater to absorb CO2(g) due to its cold temperature and chemical reactions that promote dissolution of CO2 and precipitation of carbonates and back. The purpose of this project was to determine the potential for first year Arctic sea ice to dissolve CO2(g). Sea ice pCO2 profiles were collected using a new method of remotely sampling gas in situ via diffusive membranes placed within growing sea ice. The gas samples were analysed using a GC with a TCD. Gas analysis was complimented by measurements of air and ice temperature, surface PAR, CO2(g) fluxes via the eddy correlation method and ice carbon chemistry. The work was performed on the land-fast Arctic sea ice in Franklin Bay, Canada during the winter and spring as part of the ice fast portion of the Canadian Arctic Shelf Exchange Study (CASES) 2004 project. Measurements in this experiment indicated that sea ice brine had absorbed up to twenty times the concentration of CO2(g) compared to atmospheric concentrations. Sea ice pCO2 content appears to be related to ice temperature and is a contributor to ocean-sea ice-atmosphere gas-transfer. The potential temperature relationship is expected as temperature affects sea ice brine absorption capacity and the phase of various solutes in the sea ice. There was also a dramatic diurnal pattern in sea ice pCO2, with daytime sea ice pCO2 up to ten times as great as nighttime sea ice pCO2. The observed elevation in sea ice pCO2 coupled with the mobility of the brine points to the role that brine plays in Arctic carbon transport. The gas transport links the Arctic atmosphere and ocean and indicates that a thinning and receding ice cover may not result in creating a negative feedback to the increasing atmospheric CO2(g) concentration. (Au)

G, D, E, F
Atmospheric humidity; Atmospheric temperature; Carbon; Carbon cycling; Carbon dioxide; Carbonates; Chemical properties; Chemistry; Chromatography; Composition; Cores; Diurnal variations; Equipment and supplies; Fast ice; Formation; Gases; Gases in ice; Growth; Light; Logistics; Ocean-atmosphere interaction; Physical properties; Salinity; Sea ice; Sea water; Snow; Spatial distribution; Temperature; Temporal variations; Theses; Thickness; Velocity; Water pH; Winds

G0815
Franklin Bay, N.W.T.


Physical and biological correlates of virus dynamics in the southern Beaufort Sea and Amundsen Gulf   /   Payet, J.P.   Suttle, C.A.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 933-945, ill., maps)
References.
ASTIS record 65263.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.11.002
Libraries: ACU

As part of the Canadian Arctic Shelf Exchange Study (CASES), we investigated the spatial and seasonal distributions of viruses in relation to biotic (bacteria, chlorophyll-a (chl a)) and abiotic variables (temperature, salinity and depth). Sampling occurred in the southern Beaufort Sea Shelf in the region of the Amundsen Gulf and Mackenzie Shelf, between November 2003 and August 2004. Bacterial and viral abundances estimated by epifluorescence microscopy (EFM) and flow cytometry (FC) were highly correlated (r²=0.89 and r²=0.87, respectively), although estimates by EFM were slightly higher (FC=1.08×EFM+0.12 and FC=1.07×EFM+0.43, respectively). Viral abundances ranged from 0.13×10**6 to 23×10**6/ml, and in surface waters were ~2-fold higher during the spring bloom in May and June and ~1.5-fold higher during July and August, relative to winter abundances. These increases were coincident with a ~6-fold increase in chl a during spring and a ~4-fold increase in bacteria during summer. Surface viral abundances near the Mackenzie River were ~2-fold higher than in the Mackenzie Shelf and Amundsen Gulf regions during the peak summer discharge, concomitant with a ~5.5-fold increase in chl a (up to 2.4 µg/l) and a ~2-fold increase in bacterial abundance (up to 22×10**5/ml). Using FC, two subgroups of viruses and heterotrophic bacteria were defined. A low SYBR-green fluorescence virus subgroup (V2) representing ~71% of the total viral abundance, was linked to the abundance of high nucleic acid fluorescence (HNA) bacteria (a proxy for bacterial activity), which represented 42 to 72% of the bacteria in surface layers. A high SYBR-green fluorescence viral subgroup (V1) was more related to high chl a concentrations that occurred in surface waters during spring and at stations near the Mackenzie River plume during the summer discharge. These results suggest that V1 infect phytoplankton, while most V2 are bacteriophages. On the Beaufort Sea shelf, viral abundance displayed seasonal and spatial variations in conjunction with chl a concentration, bacterial abundance and composition, temperature, salinity and depth. The highly dynamic nature of viral abundance and its correlation with increases in chl a concentration and bacterial abundance implies that viruses are important agents of microbial mortality in Arctic shelf waters. (Au)

H, I, D, J
Animal distribution; Animal population; Bacteria; Biological productivity; Biomass; Carbon; Chlorophyll; Fluorometry; Genetics; Microorganisms; Ocean temperature; Phytoplankton; Plant distribution; Plant nutrition; Predation; Salinity; Sea water; Seasonal variations; Spatial distribution; Viruses

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Dipping into the rare biosphere   /   Pedrós-Alió, C.
(Science, v.315, no.5809, 12 Jan. 2007, p. 192-193, ill.)
References.
ASTIS record 74723.
Languages: English
Web: doi:10.1126/science.1135933
Libraries: ACU

When molecular methods were introduced into microbial ecology in the mid-1980s, there were two surprises: Most DNA sequences found bore no resemblance to organisms known from cell culture, and the microorganisms that could be cultured were almost never found in molecular surveys .... These findings indicated that microbial diversity is much larger than had been anticipated. It also revealed that some bacteria occur at such low abundance that molecular techniques cannot detect them. In the meantime, marine microbiology has become an extremely active and innovative field. ... Morever, recent advances in sequencing technology are beginning to open our eyes to the huge dimensions of the microbial diversity hidden in nature. ... I will focus on marine bacteria, although most arguments may also be valid for other microorganisms. The marine environment is the largest ecosystem on Earth, and the number of rare species of microorganisms is potentially enormous. Current estimates of the total number of bacterial species range from millions to hundreds of millions. If we consider that a milliliter of seawater may contain 1 million bacterial cells, a very large number of species may be represented by just one cell. Extrapolate this number to the volume of the ocean and the diversity becomes unimaginably vast. Because of the enormous volume of the oceans, even species represented by billions of cells would be rare. An important property of this rare biosphere is that one cell of a bacterial taxon can become abundant simply by clonal replication if conditions change and become suitable for its growth. ... Another special property of the rare bacteria is that death is highly unlikely. ... Therefore, the rare taxa will persist in the environment for a long time. As a result, any habitat will have a very large biodiversity, formed by a few dozen abundant taxa plus a large collection of rare taxa that current molecular methods cannot retrieve. How can this biodiversity be explored? Pure cultures are the first approach. ... A second approach is the use of polymerase chain reaction (PCR) amplification of 16S ribosomal RNA genes present in a sample. These are then used to construct clone libraries. Normally, a set number of clones is sequenced, and statistics are used to estimate the total number of different taxa in the library. ... We can use molecular tricks in PCR to find particular microorganisms. ... But this approach will only find the target group; it will never discover novel sequences. To probe the depths of the rare biosphere, the only solution is to sequence a massive number of clones. ... More powerful, cheaper sequencing approaches are on the horizon. ... As these novel sequencing approaches are applied to diversity studies and the number of sequencing reactions increases to millions or hundreds of millions, we can expect the discovery of novel sequences to increase by at least another order of magnitude. The challenge is to retrieve the bigger picture behind those sequences. ... (Au)

H, I, J, D
Bacteria; Enzymes; Genetics; Identification; Marine biology; Microbial ecology; Microorganisms; Protozoa; Viruses

G11
Mediterranean Sea; North Atlantic Ocean


Winter activities of planktonic microorganisms during CFL   /   Pedrós-Alió, C.   Alonso-Saez, L.   Bertilsson, S.   Casamayor, E.O.   Galand, P.   Fernández-Gómez, B.   Sala, M.M.   Vaqué, D.   Estrada, M.   Romera, C.   Marrasé, C.   Rodríguez, R.   Massana, R.   Coll-Lladó, M.
In: Circumpolar Flaw Lead System Study, International Polar Year, 2007-2008 : meeting materials, CFL All-Hands Meeting, 1-5 November 2009, Winnipeg / University of Manitoba. - [Winnipeg, Man.] : University of Manitoba, 2009, p. 41
Abstract of an oral presentation.
ASTIS record 69742.
Languages: English
Libraries: ACU

Our objective for CFL was to clarify the trophic mode of planktonic prokaryotes during the Arctic winter. We designed BIOLOG plates with different polymeric organic compounds potentially important for bacteria and followed the capacity of bacterial assemblages to degrade them. We also carried out enrichment experiments in the dark and followed the development of different bacteria and archaea determining their ability to use leucine and bicarbonate by microautoradiography combined with FISH (fluorescence in situ hybridization). Finally, the number of cells taking up leucine and bicarbonate was also followed. Archaea formed a peak of abundance during the winter. This was also found in CASES. However, a very low percentage of archaea was active with the substrates tested. In CASES we tried glucose, amino acids, and ATP. Only 5% of the archaea were active. In CFL we tried bicarbonate (expecting chemolithoautotrophic) and leucine (as a control for heterotrophy). The percent of active cells was always very low with two exceptions: 12% of the cells were active in leucine uptake in June and 10% were active in bicarbonate uptake in January. This suggests a transition from autotrophic to heterotrophic archaea from winter to summer. The main source of carbon for the archaea, however, remains elusive. (Au)

H, D
Animal physiology; Animal population; Archaea; Bacteria; Biological sampling; Microorganisms; Plankton; Plant distribution; Plant physiology; Sea water; Seasonal variations; Trophic levels

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Observations of sea ice thickness, surface roughness and ice motion in Amundsen Gulf   /   Peterson, I.K.   Prinsenberg, S.J.   Holladay, J.S.
(Journal of geophysical research, v.113, no. C6, C06016, June 2008, 14 p., ill., maps)
References.
ASTIS record 65873.
Languages: English
Web: doi:10.1029/2007JC004456
Libraries: ACU

Ice thickness and surface roughness measurements of first-year (FY) sea ice were collected with a fix-mounted helicopter-borne electromagnetic (HEM)-laser system in Amundsen Gulf in April to May 2004. The modal ice thickness values are in good qualitative agreement with different ice types identified in synthetic aperture radar (SAR) imagery and shown on ice charts produced by the Canadian Ice Service. Modal ice thickness values which generally represent level ice thicknesses were about 2.0 m over landfast ice. A large range of modal ice thicknesses was observed in the mobile ice region, with values of about 0.2 m (young ice) in leads (where there was high radar backscatter), 0.6 m (thin FY ice) in the polynya (where there was medium to high backscatter), and about 1.1-1.9 m (thick FY ice) elsewhere. High surface roughnesses are strongly associated with high radar backscatter in SAR imagery, and are observed in areas of large shear. The ratio of the standard deviations of ice draft and averaged roughness in an area of landfast ice is in good agreement with the ratio of the standard deviations of ice draft and ice-equivalent roughness expected from isostasy, with constant level ice and snow thickness. However, the standard deviation of ice-equivalent roughness may be significantly underestimated, due to differences in snow thickness between level and deformed ice, and limitations of the laser processing method. Modal ice (plus snow) thicknesses measured with the HEM system are within the range of historical values measured at Cape Parry. (Au)

G, F, E, A, D
Aerial surveys; Atmospheric temperature; Deformation; Density; Electromagnetic induction; Fast ice; Helicopters; Ice cover; Ice floes; Ice leads; Instruments; Laser profilometry; Movement; Polynyas; Pressure ridges; SAR; Satellites; Sea ice; Sea water; Shear zones (Ice); Snow; Spatial distribution; Stress; Surface properties; Temporal variations; Thickness; Topography; Velocity; Winds

G0815, G07
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Parry, Cape, waters, N.W.T.


Measuring the thicknesses of the freshwater-layer plume and sea ice in the land-fast ice region of the Mackenzie Delta using helicopter-borne sensors   /   Prinsenberg, S.J.   Peterson, I.K.   Holladay, J.S.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 783-793, ill., maps)
Appendix A is supplementary data that is available online.
References.
ASTIS record 65232.
Languages: English
Web: doi:10.1016/j.jmarsys.2008.02.009
Libraries: ACU

Helicopter-borne sensors have been used since the early 1990s to monitor ice properties in support of winter marine transportation along the east coast of Canada. The observations are used in ice chart production and to validate ice hazard identification algorithms using satellite advanced synthetic aperture radar (ASAR) imagery. In this study we evaluated the sensors' additional capability to monitor the freshwater plume characteristic beneath land-fast ice. During the Canadian Arctic Shelf Exchange Study (CASES) data were collected over the Mackenzie Delta in the southern Beaufort Sea where a buoyant river plume exists. Results showed that the electromagnetic–laser system could describe not only the ice properties but also the horizontal distribution of the freshwater plume depths that decreased in depth stepwise offshore as the flow of the buoyant plume was restricted by a series of ridge-rubble fields running parallel to the coast. Relative to the 2 m mean ice thickness, the plume layer depth varied from zero under mobile offshore pack ice to 3 m inshore of the third set of ridge-rubble fields. (Au)

F, G, D, A
Aerial surveys; Classification; Drilling; Electrical properties; Electromagnetic induction; Fast ice; Ice floes; Ice leads; Ice rubble fields; Instruments; Laser profilometry; Pack ice; Pressure ridges; Remote sensing; River discharges; Rivers; Salinity; SAR; Sea water; Shear zones (Ice); Spatial distribution; Stamukhi; Surface properties; Thickness; Video tapes; Water masses

G07
Canadian Beaufort Sea


Atmospheric control of sea-ice thickness variability in the Amundsen Gulf, Canadian Beaufort Sea, and over the Labrador Shelf   /   Prinsenberg, S.J.   Peterson, I.K.   Holladay, J.S.   Galley, R.J.   Nudds, S.
(Annals of glaciology, v. 54, no. 62, 2013, p. 227-240, ill., maps)
References.
ASTIS record 77674.
Languages: English
Web: http://www.igsoc.org/annals/54/62/a62A184.pdf
Web: doi:10.3189/2013AoG62A184
Libraries: ACU

Sea-ice thicknesses observed in Canadian coastal waters with helicopter-borne electromagnetic-laser sensors show large interannual variability caused by atmospheric fluctuations in two years for two areas where surveys were repeated, one in the Amundsen Gulf of the Canadian Beaufort Sea and one over the Labrador Shelf. For the Amundsen Gulf, the bimodal ice thickness peaks shifted by 40cm to thinner thicknesses for the warmer winter of 2008 compared with 2004. The thinner ice in 2008 can be explained partially by reduced thermodynamic ice growth during the warmer winter of 2008. In addition, winds from the east were more persistent throughout the winter of 2008, increasing ice export from the Amundsen Gulf and thereby creating open-water areas where new ice growth in late winter produced the thinner ice classes. For the Labrador Shelf, the mean ice thicknesses of the warmer winter of 2011 (0.71 m) were much less than those of the near-normal winter of 2009 (1.60 m). Again the difference can be explained by the fact that along the entire Labrador Shelf the winter of 2011 was much warmer, reducing ice growth and resulting in thinner ice locally and thinner ice being transported into the survey region from northern latitudes. In addition, northwesterly winds occurred less frequently during the winter of 2011, reducing the transport of relatively thicker ice into the survey area from northern latitudes. (Au)

G, F, E, J
Aerial surveys; Atmospheric temperature; Climate change; Effects of climate on ice; Electromagnetic induction; Fast ice; Ground penetrating radar; Helicopters; Ice cover; Ice floes; Instruments; Laser profilometry; Measurement; Movement; Pack ice; Physical properties; SAR; Sea ice; Seasonal variations; Snow; Surface properties; Temporal variations; Thermodynamics; Thickness; Video tapes; Winds

G07, G08, G09
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Labrador Shelf, Labrador Sea


Parasitic infection of the hyperiid amphipod Themisto libellula in the western Canadian Arctic, including a description of Ganymedes themistos sp. n. (Apicomplexa, Gregarinia [sic])   /   Prokopowicz, A.   Rueckert, S.   Leander, B.S.   Michaud, J.   Fortier, L.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 289
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67322.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Changes in the Arctic climate will influence the life dynamic in the water column. Thus studies of the food web structure and the interaction between its components drive a new understanding of the topic. Two parasites were found in the Arctic hyperiid Amphipod Themisto libellula in the Canadian high Arctic: the gregarine Ganymedes themistos sp. n. infected the intestines and an unidentified parasitic ciliate infected the body cavity. Effects of the parasite infection on the ecology of T. libellula population were evaluated in a study carried out in the vicinity of Beaufort Sea from 2002-2004. Net collections and sediment trap samples were used. The infection of the amphipod population with Ganymedes themistos sp. n. reached 94% to 89% in the net and sediment trap samples, respectively. There was a spatial difference in the infection rates between Cape Bathurst Polynya and the open ocean area but no significant differences between Mackenzie Shelf and the polynya. The amphipods from the oceanic region appeared to be less infected, while those from the shelf and polynya were heavily parasitized. Winter 2003 was the season with the highest infection rates. Females were the most frequently parasitized, whereas males had the highest number of parasites in their intestines. Ganymedes themistos sp. n. had no effect on the growth of the female oostegites or male antennae and hence on the development of T. libellula. The gregarines were found mainly in the midgut, which may prevent them from being discharged when the host is molting. Neither of the parasites had an effect on the hosts feeding rate. Infection of the parasitic ciliates reached 81% in sediment traps and 55 % in net collections. These data indicate that the gregarines are non-harmful to their hosts, while the ciliates cause mortality in the infected individuals. (Au)

I, G, D, B
Amphipoda; Animal distribution; Animal health; Animal mortality; Bottom sediments; Food chain; Gender differences; Intestines; Parasites; Polynyas; Protozoa; Spatial distribution

G07, G0815
Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea


Écophysiologie de l'amphipode Themisto libellula sur le plateau du Mackenzie et dans la Polynie du Cap Bathurst (mer de Beaufort, océan Arctique) [Ecophysiology of the amphipod Themisto libellula on the Mackenzie Shelf and in the Cape Bathurst polynya (Beaufort Sea, Arctic Ocean)]   /   Prokopowicz, A.-J.   Fortier, L. [Supervisor]
Québec, Québec : Université Laval, 2011.
xii, 112 p. : ill., maps ; 28 cm.
References.
Thesis (Ph.D.) - Université Laval, Québec, Québec, 2011.
Indexed a PDF file available from Université Laval.
Title in French; abstract in English and French.
ASTIS record 74788.
Languages: English
Web: http://www.theses.ulaval.ca/2011/27940/27940.pdf
Libraries: QQLA

The hyperiid amphipod Themisto libellula plays a crucial role in the Arctic Ocean ecosystem. Despite this fact, its life strategy and ecophysiology is not well described. This research specifically investigated the diet, lipid content, parasitic infection and population structure of the amphipod in the south-eastern Beaufort Sea during three consecutive years (2002-2004). Extensive studies on the seasonal diet revealed that T. libellula is an omnivorous feeder. During spring and summer its stomach contained algal and Copepoda items. Cannibalistic feeding on newly hatched immature individuals appeared in females in April. The diet was well reflected by the Gas Chromatography (GC) analyzes where fatty acids 20:1(omega-9) and 22:1(omega-11) characterized Calanus prey and 20:5(omega-3) and 22:6(omega-3) specified a close connection with phytoplankton. Among different lipid classes triacylglycerol (TAG) and wax esters (WE) were dominant in females, males and also in immature individuals. Detailed analyzes brought into light the infection by two parasites: the newly described gregarine Ganymedes themistos sp. n. and an unidentified ciliate. 60.2% of guts of T. libellula were infected by gregarine and 4.4% body cavities by ciliates. The number of G. themistos increases with the size of the host in the range 8-20 mm of investigated amphipod. Considering the three regions of the study area (the Slope of the Mackenzie Shelf, the Mackenzie Shelf and the Amundsen Gulf) the least severe infection occurred on the Slope (63 ±100 G. themistos/host). We have concluded that there was no harmful effect of the gregarine on the feeding and sexual maturation of the host. In contrast, the percentage of infection compared between the net and sediment trap samples (6% vs. 16.3%, respectively) suggests that ciliates may cause the death of T. libellula. There was no difference in population structure between the three designated regions. The highest density of amphipod was observed in spring(323.4 ind./100 m³) due to newly hatched juveniles. It was concluded that T. libellula can reproduce every year and have a life span longer than 2 years. In the winter the migration of mature individuals into deeper (100 m) strata was observed while immature remained closer to the surface. Observations during the midnight sun indicate that a part of the population migrated into the surface layer during the night hours. (Au)

I, H, J, D
Algae; Amphipoda; Animal anatomy; Animal distribution; Animal ecology; Animal food; Animal health; Animal migration; Animal mortality; Animal physiology; Animal reproduction; Animal taxonomy; Biological sampling; Cannibalism; Ciliata; Copepoda; Fatty acids; Gender differences; Genetics; Intestines; Lipids; Marine ecology; Necropsy; Parasites; Phytoplankton; Protozoa; Seasonal variations; Size; Theses; Trophic levels; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Parasitic infection of the hyperiid amphipod Themisto libellula in the Canadian Beaufort Sea (Arctic Ocean), with a description of Ganymedes themistos sp. n. (Apicomplexa, Eugregarinorida)   /   Prokopowicz, A.J.   Rueckert, S.   Leander, B.S.   Michaud, J.   Fortier, L.
(Polar biology, v. 33, no. 10, Oct. 2010, p.1339-1350, ill., map)
References.
ASTIS record 71867.
Languages: English
Web: doi:10.1007/s00300-010-0821-0
Libraries: ACU

Two parasites were found in the hyperiid amphipod Themisto libellula sampled with nets and collected by sediment traps over the annual cycle in the Canadian Beaufort Sea. The trophozoites of the newly described gregarine Ganymedes themistos sp. n. infected the digestive tract of 60.2% of the T. libellula analyzed from net collections. An unidentified ciliate infected the body cavity of 4.4% of amphipods. G. themistos possessed the ball-like structure at the anterior end and the cup-like invagination at the posterior end that are typical of the genus Ganymedes. The frequency and severity (number of parasites/host) of infection by G. themistos increased with the length of T. libellula in the range 8-20 mm, and leveled off at ca. 94% and 186 trophozoites/host on average in the range 20-34 mm. Spatially, gregarine infection was less severe (63 ±100 G. themistos/host) on the Slope than on the Mackenzie Shelf (110 ±160) and in the Amundsen Gulf (132 ±157). No evidence of an impact of trophozoite infection on the feeding and sexual maturation of the host was found. For a given size of T. libellula, infection by both parasites was more frequent in the traps than in the nets (G. themistos: 91.0% vs. 82.7%; ciliates: 16.3% vs. 6%). The 2.7 times higher infection frequency in the traps suggested that the ciliate parasite may kill its host. (Au)

I, G, D, B, J
Amphipoda; Animal anatomy; Animal distribution; Animal food; Animal health; Animal mortality; Animal taxonomy; Bathymetry; Biological sampling; Bottom sediments; Food chain; Gender differences; Intestines; Marine ecology; Measurement; Parasites; Polynyas; Protozoa; Seasonal variations; Size; Spatial distribution; Trophic levels; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea


alpha-HCH enantiomer fraction (EF) : a novel approach to calculate the ventilation age of water in the Arctic Ocean?   /   Pucko, M.   Macdonald, R.W.   Barber, D.G.   Rosenberg, B.   Gratton, Y.   Stern, G.A.
(Journal of geophysical research, v.117, C08038, Aug. 2012, 7 p., ill., map)
References.
ASTIS record 76669.
Languages: English
Web: doi:10.1029/2012JC008130
Libraries: ACU

alpha-HCH (hexachlorocyclohexane) and the enantiomeric fraction (EF) of its mirror-image isomers have been determined for water column profiles in the southern Beaufort Sea in 2004 and 2007. Using estimated rates of metabolic degradation, we have applied a simple kinetic model to convert the observed EFs to apparent ventilation ages of the water masses in the study region. We found an age of 1.7 ± 0.1 years for the Polar Mixed Layer (PML), 6.6 ± 0.6 for the core of the Pacific Layer centered at salinity 33.1, and 21.7 ± 0.5 years for the core of the Atlantic Layer identified by a Tmax of ~0.5°C. These ages are in reasonable accord with other methods used to date water masses in the Arctic Ocean suggesting that alpha-HCH has an unexploited potential as a dating tool. (Au)

D, E, F, J
Age; Biodegradation; Chemical oceanography; Formation; HCH; Ice cover; Marine pollution; Mathematical models; Melting; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Runoff; Salinity; Sea ice; Sea water; Seasonal variations; Spatial distribution; Temporal variations; Water masses; Water pollution

G0813, G07, G03, G10, G141
Amundsen Gulf, N.W.T.; Arctic Ocean; Barents Sea; Canadian Beaufort Sea; Greenland Sea


When will alpha-HCH disappear from the western Arctic Ocean?   /   Pucko, M.   Stern, G.A.   Macdonald, R.W.   Barber, D.G.   Rosenberg, B.   Walkusz, W.
(Northern coastal marine studies - the Nahidik program - environmental research of the coastal Canadian Beaufort Sea / Edited by Wojciech Walkusz and William J. Williams. Journal of marine systems, v.127, Nov. 2013, p. 88-100, ill., maps)
References.
ASTIS record 74864.
Languages: English
Web: doi:10.1016/j.jmarsys.2011.09.007
Libraries: ACU

Water column concentrations of alpha-HCH were measured in the southern Beaufort Sea as part of the Canadian Arctic Shelf Exchange Study (CASES; 2003-04), the Circumpolar Flaw Lead System Study (CFL; 2007-08), and in the Mackenzie River during the 2008 NAHIDIK program. Atmospheric alpha-HCH concentrations were measured during CASES program. Inventories of alpha-HCH in the Polar Mixed Layer (PML) and the Pacific Mode Layer (PL) of the Beaufort Sea were calculated between 1986 and 2007 based on the available data. Between 1986 and 1993, there was a significant loading of alpha-HCH to the Beaufort Sea via the ocean currents. About 12% of the loading to the PML could be explained by the combined effect of the air-water gas exchange and the river runoff. After 1993, alpha-HCH inventories started decreasing, and could be well predicted exclusively by degradation. Ice formation was shown to be a solvent depleting process leading to a significant increase in the alpha-HCH concentration in the water just beneath the ice. Associated low alpha-HCH concentrations in the ice and relatively low ice export from the Beaufort Sea resulted in negligible influence of this output route on the inventories in the PML. The majority of alpha-HCH in the Beaufort Sea could be eliminated due to degradation by 2020, with concentrations in 2040 dropping to <0.006 and <0.004 ng/L in the PML and PL, respectively. Elimination of alpha-HCH from sea water takes significantly longer than from the atmosphere, with a lag of about two decades. (Au)

D, E, F, G, J
Air pollution; Atmospheric chemistry; Atmospheric circulation; Biodegradation; Chemical properties; Formation; HCH; Ice cover; Marine pollution; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Physical properties; River discharges; Sea ice; Sea water; Spatial distribution; Temporal variations; Water masses; Water pollution

G0812, G07, G03
Arctic Ocean; Canadian Beaufort Sea; Mackenzie River, N.W.T.


The effect of atmosphere-snow-ice-ocean coupling on hexachlorocyclohexane (HCH) pathways within the Arctic marine environment   /   Pucko, M.A.   Stern, G. [Supervisor]   Barber, D. [Supervisor]
Winnipeg, Man. : University of Manitoba, 2011.
xviii, 195 p. : ill., maps ; 28 cm.
References.
Thesis (Ph.D.) - University of Manitoba, Winnipeg, Man., 2011.
Indexed a PDF file from the Web available from the University of Manitoba.
Chapters 2, 3, 4, 5 have been presented as manuscripts and have been individually described as independently published in ASTIS records 71846, 73206, 74610 and 74864 respectively.
ASTIS record 76453.
Languages: English
Web: http://hdl.handle.net/1993/4767
Libraries: MWU OONL

The importance of the cryosphere, and of sea ice in particular, for contaminant transport and redistribution in the Arctic was pointed out in the literature. However, studies on contaminants in sea ice are scarce, and entirely neglect the sea ice geophysical and thermodynamic characteristics as well as interactions between various cryospheric compartments. This thesis addresses those gaps. Ice formation was shown to have a significant concentrating impact on the levels of HCHs in the water just beneath the ice. Both geophysical and thermodynamic conditions in sea ice were shown to be crucial in understanding pathways of accumulation or rejection of HCHs. Although HCH burden in the majority of the ice column remains locked throughout most of the season until the early spring, upward migration of brine from the ice to the snow in the winter has an effect on levels of HCHs in the snow by up to 50 %. In the spring, when snow melt water percolates into the ice delivering HCHs to the upper ocean via desalination by flushing, levels of HCHs in the ice can increase by up to 2 %-18 % and 4 %-32 % for alpha- and gamma-HCH, respectively. Brine contained within sea ice currently exhibits the highest HCH concentrations in any abiotic Arctic environment, exceeding under-ice water concentrations by a factor of 3 in the spring. This circumstance suggests that the brine ecosystem has been, and continues to be, the most exposed to HCHs. alpha-HCH levels were shown to decrease rapidly in the last two decades in the Polar Mixed Layer (PML) and the Pacific Mode Layer (PL) of the Beaufort Sea due to degradation. If the rate of degradation does not change in the near future, the majority of alpha-HCH could be eliminated from the Beaufort Sea by 2020, with concentrations in 2040 dropping to < 0.006 ng/L and < 0.004 ng/L in the PML and the PL, respectively. Elimination of alpha-HCH from sea water takes significantly longer than from the atmosphere, with a lag of approximately two decades. (Au)

G, D, E, F, J
Air pollution; Chromatography; Climate change; Cores; Crystals; Environmental impacts; Fast ice; Formation; HCH; Marine pollution; Mathematical models; Melting; Meteorology; Ocean-atmosphere interaction; Permeability; Physical properties; Pollution; Salinity; Sea ice; Sea water; Seasonal variations; Snow; Snowmelt; Spatial distribution; Surface properties; Temperature; Temporal variations; Thermodynamics; Theses; Water masses

G0815, G07
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Canadian Beaufort Sea


Amphipod genome sizes : first estimates for Arctic species reveal genomic giants   /   Rees, D.J.   Dufresne, F.   Glémet, H.   Belzile, C.
(Genome, v. 50, no. 2, Feb. 2007, p. 151-158, ill.)
References.
ASTIS record 63292.
Languages: English
Web: doi:10.1139/G06-155
Libraries: ACU

The genome sizes of 8 species of amphipods collected from the Canadian Arctic were estimated by flow cytometry. Haploid genome sizes ranged from 2.94 ±0.04 pg DNA in Acanthostepheia malmgreni (Oedicerotidae) to 64.62 ±2.85 pg in Ampelisca macrocephala (Ampeliscidae). The value for Ampelisca macrocephala represents the largest crustacean genome size recorded to date (and also the largest within the Arthropoda) and indicates a 400-fold variation in genome size among crustaceans. The presence of such large genomes within a relatively small sample of Arctic amphipods is striking and highlights the need to further explore the relationships between genome size, development rates, and body size in both Arctic and temperate amphipods. (Au)

I
Amphipoda; Benthos; Biological sampling; Crustacea; Genetics; Logistics; Measurement; Size

G07
Canadian Beaufort Sea


Large genomes among caridean shrimp   /   Rees, D.J.   Belzile, C.   Glémet, H.   Dufresne, F.
(Genome, v. 51, no. 2, Feb. 2008, p. 159-163, ill.)
References.
ASTIS record 64585.
Languages: English
Web: doi:10.1139/G07-108
Libraries: ACU

Recent genome size estimates for Arctic amphipods have revealed the largest genomes known in the Crustacea. Here we provide additional data for 7 species of caridean shrimp collected from the Canadian Arctic and the Gulf of St. Lawrence. Genome sizes were estimated by flow cytometry and haploid C-values ranged from 8.53 ±0.30 pg in Pandalus montagui (Pandalidae) to 40.89 ±1.23 pg in Sclerocrangon ferox (Crangonidae). The value for S. ferox represents the largest decapod genome yet recorded and indicates a 38-fold variation in genome size within this order. These data suggest that large genomes may be relatively common in Arctic crustaceans, and underline the need for further comparative studies. (Au)

I
Benthos; Biological sampling; Crustacea; Fluorometry; Genetics; Invertebrate eggs; Shrimp; Size

G0815, G07, G11
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; St. Lawrence, Gulf of, Canada


Seasonal variation in benthic community oxygen demand : a response to an ice algal bloom in the Beaufort Sea, Canadian Arctic?   /   Renaud, P.E.   Riedel, A.   Michel, C.   Morata, N.   Gosselin, M.   Juul-Pedersen, T.   Chiuchiolo, A.
(Journal of marine systems, v. 67, no. 1-2, Aug. 2007, p. 1-12, ill., map)
References.
ASTIS record 63283.
Languages: English
Web: doi:10.1016/j.jmarsys.2006.07.006
Libraries: ACU

Understanding pathways of carbon cycling on Arctic shelves is critical if we are to evaluate the potential effects of climate change on these systems. We investigated the relationship between ice algal standing stock and benthic respiration between January and July 2004 at a time series station in the southeastern Beaufort Sea. Both ice algal chlorophyll a and benthic sediment oxygen demand showed >10-fold increases from between March and April. While some of the increase in oxygen demand can be attributed to bacteria and meio-fauna, most was due to the activities of macroinfauna. We also observed a trend toward lower sediment pigment content during the pulse in benthic carbon remineralization. While chl a sedimentation also increased by a factor of 7 during this period, fluxes were not sufficient to provide for the increased carbon demand. We suggest that sedimenting ice algae provided a cue for increased benthic activity, and that direct consumption of ice algae and increased oxygen availability in the sediment due to bioturbation by epifaunal organisms led to the enhancement in respiration rates. Seasonal patterns in primary productivity and the activity of resident epifaunal and infaunal communities are, thus, important factors in determining carbon cycling patterns on Arctic shelves. (Au)

I, H, J, D, G, B
Algae; Animal food; Animal respiration; Benthos; Biological sampling; Biomass; Bottom sediments; Carbon; Carbon cycling; Chlorophyll; Cores; Fast ice; Fluorometry; Invertebrates; Logistics; Marine ecology; Measurement; Nitrogen; Ocean temperature; Oxygen; Plant growth; Plant respiration; Primary production (Biology); Salinity; Sea water; Seasonal variations; Sedimentation; Suspended solids; Thickness

G0815
Franklin Bay, N.W.T.


Carbon cycling by seafloor communities on the eastern Beaufort Sea shelf   /   Renaud, P.E.   Morata, N.   Ambrose, W.G.   Bowie, J.J   Chiuchiolo, A.
(Journal of experimental marine biology and ecology, v.349, no. 2, 19 Oct. 2007, p. 248-260, ill., map)
References.
ASTIS record 63291.
Languages: English
Web: doi:10.1016/j.jembe.2007.05.021
Libraries: ACU

Tight pelagic-benthic coupling on Arctic shelves suggests that resident benthic communities may be particularly important in the cycling of carbon and regeneration of nutrients. We sampled 16 stations in the eastern Beaufort Sea during Autumn 2003 and Summer 2004 to determine spatial patterns in sediment community carbon demand, and the manner in which that demand was partitioned among epifauna, macroinfauna, and meio-/microfauna. Sediment carbon demand in this relatively oligotrophic area was similar to that measured in more productive Arctic shelf sites, and was largely related to the distribution of phytodetritus in surface sediments. Epibenthic megafaunal communities were dominated by echinoderms and exhibited peak abundance (up to 240 ind./m²) and biomass at stations in the 60-90 m depth range. Partitioning of the carbon demand revealed the local importance of megafauna, accounting for up to 41% of the community demand. Macrofauna accounted for on average between 25 and 69% of the carbon demand, while meio-/microfauna were responsible for 31-75% of the demand. Total community carbon demand by the benthos is estimated to account for approximately 60% of the annual new production in the region, suggesting the great ecosystem importance of benthic communities on the Beaufort shelf, and potentially across the Arctic. Our study region is strongly influenced by the Mackenzie River, and ongoing climate change is likely to result in altered productivity regimes, changes in quality and quantity of available food, and higher levels of sediment deposition. Impacts of these events on benthic community structure and function will likely have repercussions throughout the ecosystem. (Au)

I, J, H, D, B
Animal distribution; Animal ecology; Animal food; Animal respiration; Bacteria; Benthos; Biological productivity; Biological sampling; Biomass; Bottom sediments; Carbon; Carbon cycling; Chlorophyll; Climate change; Cores; Crustacea; Echinoderms; Environmental impacts; Fluorometry; Invertebrates; Logistics; Marine ecology; Measurement; Oxygen; Photography; Sedimentation

G07, G0815
Alaskan Beaufort Sea; Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Comparison of the optical properties of dissolved organic matter in two river-influenced coastal regions of the Canadian Arctic   /   Retamal, L.   Vincent, W.F.   Martineau, C.   Osburn, C.L.
(Estuarine, coastal and shelf science, v. 72, no. 1-2, Mar. 2007, p. 261-272, ill., maps)
References.
ASTIS record 63263.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/212.pdf
Web: doi:10.1016/j.ecss.2006.10.022
Libraries: ACU

The optical characteristics of coloured dissolved organic matter (CDOM) were analyzed in the Great Whale River and adjacent Hudson Bay (55° N, 77° W) in the eastern Canadian Low Arctic, and in the Mackenzie River and adjacent Beaufort Sea in the western Canadian High Arctic (70° N, 133° W). Sampling was during ice-free open water conditions. Both rivers contained high concentrations of dissolved organic carbon (3 and 6 mg DOC/l in the Great Whale River and Mackenzie River, respectively) and CDOM (alpha 320 of 11 and 14/m), resulting in a substantial load of organic matter to their coastal seas. There were pronounced differences in the CDOM characteristics of the two rivers, notably in their synchronous fluorescence scans (SFS). The latter showed that the Mackenzie River was depleted in humic materials, implying a more mature catchment relative to the younger, more recently glaciated Great Whale River system. SFS spectra had a similar shape across the freshwater-saltwater transition zone of the Great Whale plume, and DOC was linearly related to salinity implying conservative mixing and no loss by flocculation or biological processes across the salt front. In contrast, there were major differences in SFS spectral shape from the Mackenzie River to the freshwater-influenced coastal ocean, with a marked decrease in the relative importance of fulvic and humic acid materials. The SFS spectra for the coastal Beaufort Sea in September-October strongly resembled those recorded for the Mackenzie River during the high discharge, CDOM-rich, snowmelt period in June, but with some loss of autochthonous materials. These results are consistent with differences in freshwater residence time between the Mackenzie River and Great Whale River coastal ocean systems. Models of arctic continental shelf responses to present and future climate regimes will need to consider these striking regional differences in the organic matter content, biogeochemistry and optics between waters from different catchments and different inshore hydrodynamic regimes. (Au)

D, F, J, B, I, A, H, G, E
Algae; Bacteria; Biological productivity; Carbon cycling; Chemical properties; Climate change; Colored dissolved organic matter; Continental shelves; Dissolved organic carbon; Estuaries; Flocculants; Fluorometry; Food chain; Fresh-water ecology; Hydrodynamics; Impurities; Light; Measurement; Microbial ecology; Ocean temperature; Optical properties; Pack ice; Photosynthesis; Physical properties; Phytoplankton; River discharges; Rivers; Salinity; Sea ice; Sea ice ecology; Seasonal variations; Sediment transport; Surface properties; Suspended solids; Ultraviolet radiation; Water masses; Water pH

G0812, G07, G0826, G0814, G14, G03
Arctic Ocean; Baleine, Grande rivière de la, Québec; Beaufort Sea; Hudson Bay; Kuujjuarapik, Québec; Mackenzie River, N.W.T.; Yenisey River, Russian Federation


Effet optique de la matière organique dissoute colorée sur la production primaire dans des systèmes d'estuaires nordiques : qualité, quantité et changements climatiques   /   Retamal, L.   Vincent, W.F. [Supervisor]
Québec, Québec : Université Laval, 2007.
xvi, 136 p. : ill., maps ; 28 cm.
Thesis (Ph.D) - Université Laval, Québec, Québec, 2007.
References.
Front material, general abstract, general introduction and general conclusion are in French; core chapters are in English.
Chapter 2, as published separately, is described in ASTIS record 63263.
ASTIS record 74982.
Languages: English or French
Web: http://archimede.bibl.ulaval.ca/archimede/meta/24859
Libraries: OONL

Résumé général: Dans les régions nordiques, les changements climatiques sur les milieux terrestres auront des conséquences encore peu connues sur les écosystèmes aquatiques. La fonte du pergélisol et le changement de la composition végétale auront pour effets de libérer des concentrations élevées de matière organique allochtone vers les écosystèmes aquatiques. Cette matière organique dissoute colorée (CDOM) joue un rôle majeur dans l'atténuation de l'éclairement subaquatique. Cette étude s'intéresse aux effets optiques de la qualité et de la quantité du CDOM en système estuarien nordique. Le CDOM des systèmes d'estuaires de la Grande Rivière de la Baleine et du fleuve Mackenzie a été caractérisé par absorption et par fluorescence synchrone. Ces analyses ont révélé des différences fondamentales entre ces deux systèmes en terme de qualité et de quantité de CDOM. Cependant, une signature de fluorescence particulière a été mise en évidence pour le CDOM nordique, celle-ci étant plus constante que les propriétés d'absorption du CDOM. L'importance optique du CDOM dans l'atténuation de la radiation solaire a été observée dans le système estuarien du fleuve Mackenzie, rivière reconnue pour l'influence des particules sur l'éclairement subaquatique. Les stratégies pigmentaires, la composition du phytoplancton et la production primaire ont également été mesurés. Le CDOM et la matière particulaire contrôlaient l'éclairement dans le visible (400-700 nm), mais seule le CDOM affectait la radiation ultraviolette (<400 nm). Contrairement à la matière particulaire, l'effet optique du CDOM fluvial était mesurable même au-delà de l'épanchement du fleuve Mackenzie, sur le plateau de la Mer de Beaufort. L'impact d'un accroissement de la concentration de CDOM allochtone sur la production primaire a été mesuré dans le système d'estuaire de la Grande Rivière de la Baleine. Les analyses par modélisation ont montré que les modifications du régime spectral affectent la quantité d'éclairement disponible pour la photosynthèse, la profondeur de la zone euphotique, ainsi que le couplage spectral du phytoplancton. En utilisant l'approche expérimentale, les paramètres photosynthétiques ont été mesurés sous un régime spectral modifié par une concentration accrue de CDOM allochtone. Ceci a permis de démontrer que de hautes concentrations de CDOM contribuent à une réduction significative de la production primaire dans la colonne d'eau. (Au)

D, F, J, B, I, A, H, G, E
Algae; Bacteria; Biological productivity; Carbon cycling; Chemical properties; Chlorophyll; Climate change; Continental shelves; Estuaries; Flocculants; Fluorometry; Food chain; Fresh-water ecology; Hydrodynamics; Impurities; Isotopes; Light; Measurement; Microbial ecology; Ocean temperature; Optical properties; Pack ice; Photosynthesis; Physical properties; Phytoplankton; Primary production (Biology); River discharges; Rivers; Salinity; Sea ice; Sea ice ecology; Seasonal variations; Sediment transport; Surface properties; Suspended solids; Theses; Ultraviolet radiation; Water masses; Water pH

G0812, G07, G0826, G0814
Baleine, Grande rivière de la, Québec; Beaufort Sea; Hudson Bay; Kuujjuarapik, Québec; Mackenzie River, N.W.T.


Optical gradients and phytoplankton production in the Mackenzie River and the coastal Beaufort Sea   /   Retamal, L.   Bonilla, S.   Vincent, W.F.
(Polar biology, v. 31, no. 3, Feb. 2008, p. 363-379, ill., maps)
References.
ASTIS record 64996.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/220.pdf
Web: doi:10.1007/s00300-007-0365-0
Libraries: ACU

We sampled a 300-km transect along the Mackenzie River and its associated coastal shelf system (western Canadian Arctic) in July-August of 2004 to evaluate the gradients in optical, phytoplankton and photosynthetic characteristics. The attenuation of photosynthetically available radiation (PAR) was best explained by coloured dissolved organic matter (CDOM) and turbidity (non-algal particles), while UV attenuation correlated most strongly with CDOM. Bacillariophyceae and Chlorophyceae dominated in the river, and shifted to Cryptophyceae and Prasinophyceae in the estuarine transition zone. In the coastal shelf waters, picoplanktonic cells dominated the surface autotrophic communities while both large and small cells occurred in the deep chlorophyll maximum. High PAR attenuation reduced the integral primary production rate in the river, while at an offshore marine site, 55% of integral production was at or below the pycnocline, under low PAR. Climate change is likely to increase the sediment and CDOM loading to these waters, which would exacerbate light limitation of photosynthesis throughout the system. (Au)

D, F, J, B, I, A, H, G, E, C
Algae; Bacteria; Biological productivity; Carbon cycling; Chemical properties; Chlorophyll; Climate change; Colored dissolved organic matter; Continental shelves; Diatoms; Estuaries; Estuarine ecology; Fluorometry; Food chain; Fresh-water ecology; Hydrodynamics; Hydrological stations; Impurities; Light; Marine ecology; Measurement; Microbial ecology; Ocean temperature; Optical properties; Pack ice; Permafrost; Photosynthesis; Physical properties; Phytoplankton; Plant distribution; Primary production (Biology); River discharges; Rivers; Salinity; Sea ice; Sea ice ecology; Seasonal variations; Sediment transport; Solar radiation; Surface properties; Suspended solids; Thawing; Ultraviolet radiation; Water masses; Water pH

G0812, G07, G03, G14
Arctic Ocean; Beaufort Sea; Lena, Reka, Russian Federation; Mackenzie Delta, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.; Ob' River, Russian Federation; Yenisey River, Russian Federation


Distribution spatiale des assemblages de dinokystes dans les sédiments de surface et évolution des conditions paléocéanographiques récentes dans la fosse du Mackenzie, mer de Beaufort (Canada)   /   Richerol, T.   Rochon, A. [Supervisor]
Rimouski, Québec : Université du Québec à Rimouski, 2007.
xiii, 95 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR34832)
ISBN 978-0-494-34832-1
References.
Thesis (M.Sc.) - Université du Québec à Rimouski, Rimouski, Québec, 2007.
Front material, general introduction, chapter 2, and general conclusion in French; chapter 1 in English.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 64402.
Languages: English and French
Web: http://semaphore.uqar.ca/67/
Libraries: QRU OONL

In order to document long-term climate cycles and predict future climate trends for the Arctic, we need to look at the geological record to establish the link between historical and pre-historical sea surface parameters. Dinoflagellate cysts (dinocysts) are used as proxy indicators of sea surface parameters (temperature, salinity, sea-ice cover, primary productivity) jointly with transfer functions and a modern dinocyst reference database, to reconstruct the evolution of sea surface conditions at decadal and millennial timescales. Here we present the surface distribution of recent dinocyst assemblages from 34 surface sediment samples collected on the Mackenzie Slope/Amundsen Gulf during the 2004 CASES (Canadian Arctic Shelf Exchange Study) cruise. Dinocyst concentrations in surface sediments are relatively high outside the Mackenzie plume area and increase gradually eastward toward Amundsen Gulf. The cysts of autotrophic dinoflagellates are dominant throughout the study area, while the maximum abundance of heterotrophic taxa is found within the Mackenzie plume. Hierarchical clustering analyses allowed defining two dinocyst assemblages. Assemblage 1 is located on the Mackenzie Slope and southern Amundsen Gulf, while assemblage II is located within the Cape Bathurst Polynya area in northern Amundsen Gulf. Both assemblages are dominated by Operculodinium centrocarpum, but are distinguished on the basis of the relative abundance of Islandinium minutum, a taxon generally associated with sea ice. Islandinium minutum is found in lower abundance in the Cape Bathurst Polynya. [Abstract taken from Chapter 1.] (Au)

D, B, H, I, E, J, G
Algae; Animal distribution; Bottom sediments; Classification; Climate change; Cores; Dinoflagellata; Environmental impacts; Forecasting; Ice cover; Identification; Lead; Logistics; Ocean temperature; Oceanography; Palynology; Palynomorphs; Plankton; Plant distribution; Primary production (Biology); Radioactive dating; Recent epoch; Salinity; Sea ice; Sedimentation; Soil profiles; Suspended solids; Temporal variations; Theses

G07, G0815
Amundsen Gulf, N.W.T.; Beaufort Sea; Mackenzie Trough, Canadian Beaufort Sea


Distribution of dinoflagellate cysts in surface sediments of the Mackenzie shelf and Amundsen Gulf, Beaufort Sea (Canada)   /   Richerol, T.   Rochon, A.   Blasco, S.   Scott, D.B.   Schell, T.M.   Bennett, R.J.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 825-839, ill., maps)
References.
ASTIS record 65259.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.11.003
Libraries: ACU

In order to document long-term climate cycles and predict future climate trends for the Arctic, we need to look at the geological records to establish the link between historical and pre-historical sea-surface parameters. Dinoflagellate cysts (dinocysts) are used as proxy indicators of sea-surface parameters (temperature, salinity, sea-ice cover, primary productivity) jointly with transfer functions and a modern dinocyst reference database, to reconstruct the evolution of sea-surface conditions at decadal and millennial timescales. Here we present the surface distribution of recent dinocyst assemblages from 34 surface sediment samples collected on the Mackenzie Slope/Amundsen Gulf during the 2004 CASES (Canadian Arctic Shelf Exchange Study) cruise. Dinocyst concentrations in surface sediments are relatively high outside the Mackenzie plume area and increase gradually eastward toward Amundsen Gulf. The cysts of autotrophic dinoflagellates are dominant throughout the study area, while the maximum abundance of heterotrophic taxa is found within the Mackenzie plume. Hierarchical clustering analyses allowed defining two dinocyst assemblages. Assemblage I is located on the Mackenzie Slope and southern Amundsen Gulf, while Assemblage II is located within the Cape Bathurst Polynya area in northern Amundsen Gulf. Both assemblages are dominated by Operculodinium centrocarpum, but are distinguished on the basis of the relative abundance of Islandinium minutum, a taxon generally associated with sea ice. I. minutum is found in lower abundance in the Cape Bathurst Polynya. (Au)

I, H, D, J
Animal distribution; Animal taxonomy; Biological productivity; Biological sampling; Bottom sediments; Carbon; Cores; Dinoflagellata; Ice cover; Ocean temperature; Palynology ; Palynomorphs; Plant distribution; Plant taxonomy; Salinity; Sea ice; Seasonal variations; Sedimentation

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea


Evolution of paleo sea-surface conditions over the last 600 years in the Mackenzie Trough, Beaufort Sea (Canada)   /   Richerol, T.   Rochon, A.   Blasco, S.   Scott, D.B.   Schell, T.M.   Bennett, R.J.
(Dinocysts as tracers of hydrographical conditions and productivity along the ocean margins / Edited by A. de Vernal, A. Rochon and F. Eynaud. Marine micropaleontology, v. 68, no. 1-2, July 2008, p. 6-20, ill., maps)
References.
ASTIS record 65290.
Languages: English
Web: doi:10.1016/j.marmicro.2008.03.003
Libraries: ACU

In order to document long-term climate trends and predict future climate change for the Arctic, we need to look at the geological record to establish the link between historical and pre-industrial sea-surface parameters. Dinoflagellate cysts (dinocysts) are used as proxy indicators of sea-surface parameters (temperature, salinity, sea-ice cover, primary productivity) jointly with transfer functions and a modern dinocyst reference database, to reconstruct the evolution of sea-surface conditions at decadal and multi-decadal timescales. Here we present the fossil dinocyst assemblages established from three sediment cores collected along an inshore-offshore transect in the Mackenzie Trough during the 2004 CASES (Canadian Arctic Shelf Exchange Study) cruise. The chronology of each core was determined using 210Pb activity and AMS-14C measurements in core 912A. Sediment cores 912A, 909B and 906B cover the last 600, 200 and 100 years respectively. Palynomorph influxes increase from the bottom to the top of each core, illustrating an increasing productivity over the last 600 years until 1850 AD, when we observe a decrease of productivity until today. We determined a succession of two assemblages over the last 600 years. Assemblage I, at the base of each core, is mostly composed of dinocysts from heterotrophic taxa. The modern assemblage (Assemblage II at the top of each core) is mostly composed of dinocysts from autotrophic taxa. Quantitative reconstructions of sea-surface parameters reveal a sharp increase in summer (August) temperature (2 to 5 °C) throughout the study area from 1400 AD until 1800-1850 AD, after which the increase (between 0.5 and 1.0 °C) is much slower until modern times. (Au)

D, B, H, I, E, J, G
Animal distribution; Atmospheric temperature; Bottom sediments; Classification; Climate change; Cores; Dinoflagellata; Environmental impacts; Forecasting; Ice cover; Lead; Ocean temperature; Palaeoecology; Palaeontology; Palynology; Palynomorphs; Plankton; Plant distribution; Primary production (Biology); Radioactive dating; Radiocarbon dating; Radionuclides; Recent epoch; Salinity; Sea ice; Sedimentation; Soil profiles; Soil texture; Spores; Suspended solids; Temporal variations

G07, G0815
Amundsen Gulf, N.W.T.; Beaufort Sea; Mackenzie Trough, Canadian Beaufort Sea


Seasonal study of sea-ice exopolymeric substances on the Mackenzie shelf : implications for transport of sea-ice bacteria and algae   /   Riedel, A.   Michel, C.   Gosselin, M.
(Aquatic microbial ecology, v. 45, no. 2, Nov. 2006, p. 195-206, ill., maps)
References.
ASTIS record 63266.
Languages: English
Web: doi:10.3354/ame045195
Libraries: AEU

Bottom sea ice, from under high and low snow cover, and surface water samples were collected in Franklin Bay (Mackenzie shelf) on 21 occasions between 24 February and 20 June 2004 and analyzed for exopolymeric substances (EPS), particulate organic carbon (POC) and chlorophyll a (chl a). Concentrations of EPS were measured using Alcian blue staining of melted ice samples. Chl a and bacterial sinking velocities were also assessed with settling columns, to determine the potential role of EPS in the transport of sea-ice biomass. EPS concentrations in the bottom ice were consistently low in March (avg. 185 µg xanthan equivalents / l), after which they increased to maximum values of 4930 and 10500 µg Xequiv. / l under high and low snow cover, respectively. EPS concentrations in the surface water were consistently 2 orders of magnitude lower than in the sea ice. Sea-ice EPS concentrations were significantly correlated with sea-ice chl a biomass (tau = 0.70, p < 0.01). Sea-ice algae were primarily responsible for EPS production within the sea ice, whereas bacteria produced insignificant amounts of sea-ice EPS. EPS-carbon contributed, on average, 23% of POC concentrations within the sea ice, with maximum values reaching 72% during the melt period. Median chl a sinking velocities were 0.11 and 0.44 m/d under high and low snow cover, respectively. EPS had little effect on chl a sinking velocities. However, bacterial sinking velocities did appear to be influenced by diatom-associated and free EPS within the sea ice. Diatom-associated EPS could facilitate the attachment of bacteria to algae thereby increasing bacterial sinking velocities, whereas the sinking velocities of bacteria associated with positively buoyant, free EPS, could be reduced. EPS contributed significantly to the sea-ice carbon pool and influenced the sedimentation of sea-ice biomass, which emphasizes the important role of EPS in carbon cycling on Arctic shelves. (Au)

J, G, H, F, A
Algae; Bacteria; Biomass; Carbohydrates; Carbon; Carbon cycling; Chlorophyll; Continental shelves; Cores; Diatoms; Light; Microbial ecology; Phytoplankton; Primary production (Biology); Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Sedimentation; Snow cover; Sugars; Surface properties; Suspended solids

G0815, G15
Antarctic waters; Franklin Bay, N.W.T.


Enrichment of nutrients, exopolymeric substances and microorganisms in newly formed sea ice on the Mackenzie shelf   /   Riedel, A.   Michel, C.   Gosselin, M.   LeBlanc, B.
(Marine ecology. Progress series (Halstenbek), v.342, July 24, 2007, p. 55-67, ill., maps)
References.
ASTIS record 63906.
Languages: English
Web: doi:10.3354/meps342055

Newly formed sea ice was sampled at 32 stations on the Mackenzie shelf, between 30 September and 19 November 2003. At each station, sea ice and surface waters were analysed to assess the concentration and enrichment of nutrients, exopolymeric substances (EPS, measured with Alcian blue), chlorophyll a (chl a), autotrophic and heterotrophic protists, and heterotrophic bacteria. Dark incubations were also conducted to estimate net heterotrophic NH4 regeneration rates in sea ice <5 cm thick. Large (>=5 µm) autotrophs were selectively enriched during sea-ice formation, having the highest average enrichment index (IS = 62), although heterotrophic protists (IS = 19), EPS (IS = 17), bacteria (IS = 6) and dissolved inorganic nitrogen (IS = 3 to 5) were also significantly enriched in the sea ice. Significant relationships were observed between sea-ice EPS and total chl a concentrations (r = 0.59, p < 0.001) and between sea-ice EPS and >=5 µm autotroph enrichment indices (r = 0.48, p < 0.01), suggesting that EPS were actively produced by algae entrapped in the sea ice. These relationships also suggest that the presence of EPS may enhance the selective enrichment of large autotrophs. Heterotrophic regeneration contributed to the observed enrichment of NH4 in the sea ice, with an average regeneration rate of 0.48 µM/d, contributing 67% of the sea-ice NH4 concentrations. In the newly formed ice, NH4 regeneration was coupled to NO3 and Si(OH)4 consumption and was significantly related to EPS concentrations (r = 0.87, p < 0.05). Our data suggest that EPS enhance NH4 regeneration by acting as a carbon source for sea-ice heterotrophs or a substrate for sea-ice bacteria. (Au)

I, H, J, G, D, F
Algae; Animal distribution; Animal food; Animal population; Carbohydrates; Carbon; Carbon cycling; Chlorophyll; Cores; Diatoms; Fluorometry; Formation; Frazil ice; Heterotrophic bacteria; Marine ecology; Microbial ecology; Microorganisms; Nitrogen; Phosphorus; Plant distribution; Plant nutrition; River discharges; Salinity; Sea ice; Sea ice ecology; Silica; Sugars; Suspended solids; Thickness; Water masses

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon


Grazing of large-sized bacteria by sea-ice heterotrophic protists on the Mackenzie shelf during the winter-spring transition   /   Riedel, A.   Michel, C.   Gosselin, M.
(Aquatic microbial ecology, v. 50, no. 1, Dec. 2007, p. 25-38, ill., maps)
References.
ASTIS record 63911.
Languages: English
Web: doi:10.3354/ame01155
Libraries: OON

Heterotrophic bacterial dynamics were assessed in the sea ice and surface waters on the Mackenzie Shelf (Beaufort Sea), from 5 March to 3 May 2004. On 11 occasions, heterotrophic protist bacterivory was assessed from the disappearance of fluorescently labeled bacteria (FLB) in sea-ice samples collected from areas of high and low snow cover. Concurrently, sea-ice and surface water samples were analyzed for dissolved organic carbon (DOC), exopolymeric substances (EPS) and chlorophyll a concentrations, and protist and bacterial abundances. Total bacterial abundances were significantly higher in the sea ice than in surface waters. However, DOC concentrations and abundances of large (>=0.7 µm) bacteria were not significantly higher in the sea ice as compared to surface waters. This suggests that DOC was being released from the sea ice, potentially supporting the growth of large-sized bacteria at the ice-water interface. Heterotrophic protist (HP) bacterivory averaged 57%/d of large-sized bacterial abundances in the sea ice with ingestion rates averaging 768 and 441 bacteria/HP/d, under high and low snow cover, respectively. High concentrations of EPS during the sea-ice algal bloom may have interfered with the grazing activities of heterotrophic protists as indicated by the significant negative correlations between ingestion rates and EPS-carbon concentrations under high (tau = -0.57, p < 0.05) and low (tau = -0.56, p < 0.05) snow cover. Bacterivory satisfied heterotrophic protist carbon requirements prior to, but not during, the sea-ice algal bloom, under high and low snow cover. EPS may have been an additional carbon source for the heterotrophs, especially during the sea-ice algal bloom period. This study provides evidence of an active heterotrophic microbial food web in first-year sea ice, prior to and during the sea-ice algal bloom. This study also highlights the significance of DOC and EPS as integral components of the microbial food web within the sea ice and surface waters of Arctic shelves (Au)

J, I, H, G, F, D
Algae; Animal food; Animal population; Biomass; Carbohydrates; Carbon; Carbon cycling; Chlorophyll; Cores; Diatoms; Dissolved organic carbon; Fluorometry; Food chain; Grazing; Heterotrophic bacteria; Light; Microbial ecology; Microorganisms; Nitrogen; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Snow; Sugars; Thickness; Trophic levels

G0815
Franklin Bay, N.W.T.


Winter-spring dynamics in sea-ice carbon cycling in the coastal Arctic Ocean   /   Riedel, A.   Michel, C.   Gosselin, M.   LeBlanc, B.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 918-932, ill., maps)
References.
ASTIS record 65240.
Languages: English
Web: doi:10.1016/j.jmarsys.2008.01.003
Libraries: ACU

An understanding of microbial interactions in first-year sea ice on Arctic shelves is essential for identifying potential responses of the Arctic Ocean carbon cycle to changing sea-ice conditions. This study assessed dissolved and particulate organic carbon (DOC, POC), exopolymeric substances (EPS), chlorophyll a, bacteria and protists, in a seasonal (24 February to 20 June 2004) investigation of first-year sea ice and associated surface waters on the Mackenzie Shelf. The dynamics of and relationships between different sea-ice carbon pools were investigated for the periods prior to, during and following the sea-ice-algal bloom, under high and low snow cover. A predominantly heterotrophic sea-ice community was observed prior to the ice-algal bloom under high snow cover only. However, the heterotrophic community persisted throughout the study with bacteria accounting for, on average, 44% of the non-diatom particulate carbon biomass overall the study period. There was an extensive accumulation of sea-ice organic carbon following the onset of the ice-algal bloom, with diatoms driving seasonal and spatial trends in particulate sea-ice biomass. DOC and EPS were also significant sea-ice carbon contributors such that sea-ice DOC concentrations were higher than, or equivalent to, sea-ice-algal carbon concentrations prior to and following the algal bloom, respectively. Sea-ice-algal carbon, DOC and EPS-carbon concentrations were significantly interrelated under high and low snow cover during the algal bloom (r values >=0.74, p<0.01). These relationships suggest that algae are primarily responsible for the large pools of DOC and EPS-carbon and that similar stressors and/or processes could be involved in regulating their release. This study demonstrates that DOC can play a major role in organic carbon cycling on Arctic shelves. (Au)

G, J, H, I, D
Algae; Bacteria; Biological sampling; Biomass; Carbohydrates; Carbon; Carbon cycling; Chlorophyll; Cores; Diatoms; Dissolved organic carbon; Fast ice; Fluorometry; Growth; Light; Melting; Microbial ecology; Microorganisms; Nitrogen; Phosphorus; Plant growth; Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Silica; Snow; Spatial distribution; Sugars; Suspended solids; Thickness

G0815
Franklin Bay, N.W.T.


CASES 2004, Leg 9 CCGS Amundsen cruise & preliminary data report and ArcticNet preliminary cruise report 05 August to 25 August, 2004   /   Rochon, A. [Editor]
[Québec, Québec : Université Laval, 2004].
[55] p. : ill., maps ; 28 cm.
Cover title.
Indexed a PDF file from the Web.
References.
Appendices.
ASTIS record 74427.
Languages: English
Web: http://www.cases.quebec-ocean.ulaval.ca/CASES0304_leg9_cruise_report.pdf

This report describes the scientific studies carried out in Leg 9 of the CASES 2004 and ArcticNet CCGS Amundsen cruise, which included the following reports: Leg 9 cruise report, Contaminants; Phytoplankton dynamics and microphytobenthos characteristics in the Cape Bathurst polynya and in the Amundsen Gulf along with preliminary stations of Arctic Net; Cruise Report Leg 9 - Free-drifting Sediment Traps; Geology Report for Leg 9 (04 August - 26 August 2004) - CASES & Arctic Net; Cruise Report of the Japanese CASES team on Leg 9; Microbial ecology CASES 2003-2004 Leg 9; Ocean Mapping Group Cruise Report; Nutrients and New Production : Cruise report for the CASES and ArcticNet components of Leg 9; Zooplanton / Young-Fish Team Report CASES 03/04 Leg 9; CASES Leg 9 report : theme 5: Pelagic Food Web Structure, function and contaminants - theme 6: Organic and inorganic fluxes - theme 7: Benthic processes and carbon cycling. This report also contains: Leg 9 log of daily activities; an Operation Plan; a Detailed list of stations. (ASTIS)

D, G, E, J, L, F, B, H, I, A
Air pollution; Amundsen (Ship); Animal tagging; ArcticNet Inc.; Atmospheric chemistry; Atmospheric circulation; Bacteria; Beluga whales; Benthos; Biological sampling; Biomass; Bottom sediments; Canadian Arctic Shelf Exchange Study; Carbon cycling; Chemical oceanography; Chemical properties; Climate change; Copepoda; Cores; Effects monitoring; Fishes; Geochemistry; Ice navigation; Instruments; Light; Mapping; Measurement; Mercury; Microbial ecology; Microorganisms; Ocean floors; Ocean-atmosphere interaction; Oceanography; Oxygen-18; Phytoplankton; Plankton; Primary production (Biology); River discharges; Salinity; Sea ice; Sea water; Snow; Submarine topography; Suspended solids; Temporal variations; Water pollution; Zooplankton

G0815, G07, G0812
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Dease Strait, Nunavut; Lancaster Sound, Nunavut; Mackenzie Delta, N.W.T.; Mackenzie River, N.W.T.; Northwest Passage


Evolution of sea surface conditions in the Beaufort Sea during pre-historical and historical times : the last ~1000 years   /   Rochon, A.   Richerol, T.
In: CMOS-CGU-AMS Congress 2007 : air, ocean, earth and ice on the rock : program and abstracts = Congrés SCMO-UGC-AMS 2007 : air, océan, terre et glace sur le roc : programme et résumés. - St. John's, Nfld. : CMOS/CGU/AMS, 2007, [1] p.
Abstract of an oral presentation in Session I13-4B9.1, ID:1817.
Session I13-4B9: International Polar Year Activities.
Joint meeting of the Canadian Meteorological and Oceanographical Society (41st Congress), the Canadian Geophysical Union (Thirty-third Annual Meeting), and the American Meteorological Society (Ninth Conference on Polar Meteorology and Oceanography) held in St. John's Newfoundland from May 28 to June 1, 2007.
ASTIS record 75615.
Languages: English
Web: http://www.cmos.ca/CongressAbstracts/cong4107.pdf

In order to reconstruct the evolution of sea surface parameters (temperature, salinity, sea ice cover) in the Beaufort Sea for the historical and prehistorical period, and assess the impact of anthropogenic activities, a series of 3 boxcores was collected in the Mackenzie Trough as part of the CASES program. Dinoflagellate cysts (dinocyst) and freshwater palynomorphs are used as proxy indicators of sea surface conditions and freshwater input, respectively. The cores were dated using 210Pb, and range from 1000 A.D. to the modern period, providing a pluriannual to decennial-scale resolution for our reconstructions. The highest sedimentation rate (1.2 mm/yr) is recorded at the offshore site, and it decreases gradually toward the mouth of the Mackenzie River (0.4 mm/yr). The energy at the river mouth induces a bypass of the proximal trench and shelf areas, allowing sediment deposition further offshore. We observe the passage from a heterotrophic to an autotrophic regime over the last 1000 years, which we associate with increased nutrient input and/or increased open water conditions throughout the study area. The period between 1000 and 1550 A.D. is marked by low sea surface temperature, high sea ice cover and reduced primary productivity. The Little Ice Age period (1550 to 1850 A.D.) is marked by maximum dinocyst fluxes (enhanced productivity) and low sea surface temperature in surface waters. The maximum abundance of freshwater palynomorhs, accompanied by a reduction of salinity suggests increased freshwater inflow from the Mackenzie River. The industrial period (1850 A.D. and onward) is marked by a decrease of dinocyst fluxes by a factor of 2.5. These data suggest that anthropogenic activities over the last 160 years may be related to the decrease in surface productivity in the Beaufort Sea. However, we do not observe a clear warming or cooling trend with respect to the reconstructed sea surface parameters. (Au)

B, D, H, I, G
Animal distribution; Bottom sediments; Cores ; Dinoflagellata; Ice cover; Lead; Ocean temperature; Oceanography; Palynomorphs; Plant distribution; Plant nutrition; Primary production (Biology); Radioactive dating; Radionuclides; River deltas; River discharges; Rivers; Salinity; Sea ice; Sediment transport; Sedimentation; Spatial distribution; Surface temperature; Temporal variations; Water masses

G07, G0812
Canadian Beaufort Sea; Mackenzie Delta, N.W.T.; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Marine paleoenvironments in the Canadian Arctic : what have we learned in recent years?   /   Rochon, A.   St-Onge, G.   Scott, D.B.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 141-142
Abstract of a Topical Session presentation.
Indexed a PDF file from the Web.
ASTIS record 66993.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Prior to the onset of the CASES program in 2002, which was followed by ArcticNet in 2004, our knowledge of the Holocene (last 10,000 years) paleoceanographical changes that took place in the Canadian Arctic was limited. Although sediment distribution from the different areas was relatively well known, no high-resolution sedimentary sequences were available for paleoceanographic studies. The extensive multibeam and sub-bottom profiling programs of these areas, which began in 2002, helped identifying areas of high sediment accumulation, with sedimentation rates at least one order of magnitude higher (i.e., >100 cm/ka) than previous paleoceanographic records. Since then, we have collected several sediment cores throughout the Canadian Arctic that provided, for the first time, time-series of Holocene oceanographical changes at resolutions varying from millennial to multi-annual. The major feature of these studies illustrate the opposite climate trends between the Eastern and Western Canadian Arctic. In the Eastern Arctic, the Holocene climatic optimum occurred around ~6500 to 4000 BP (depending on the location), after which sea surface temperatures began to cool until modern times through a series of warm/cold oscillations. In the western Arctic (Beaufort Sea), we observe the opposite trend, with sea surface conditions increasing over at least the last 9000 years, also through a series of warm/cold oscillations. In the Mackenzie Trough we were able to document paleoceanographic changes at a resolution <10 years, and therefore document changes associated with the onset of the industrial era. The analysis of sediment cores from the central part of the Northwest Passage indicates that sea surface conditions remained stable over the last 8000 years (see Ledu et al., this meeting). In addition, we have now documented the spatial distribution of foraminifers and dinoflagellate cysts, two of the main proxies for the reconstruction of sea surface (temperature, salinity, sea ice cover) and bottom water conditions. One of the main problems that we encountered when studying Arctic sediment cores is the lack of datable material, which limits the accuracy of the chronological framework of each core. Usually, the tests of foraminifers (composed of CaCO3) are used for radiocarbon dating, but because calcium carbonates are dissolved in cold environments, there is often not enough material to obtain a reliable age. Another problem is that the sediment supply is low in the Arctic, and basins where suitable sediments accumulate are usually in water depths >500 meters. Few mollusks live in these environments, which further reduces the possibility of obtaining age control. Furthermore, the low abundance of organic matter in the sediments prevents the use of bulk sediment dating techniques. Therefore, other means for dating sediments must be used. As such, we now rely on the relative dating technique provided by the study of the variations of the Earth's magnetic field (inclination, declination, relative paleointensity). Indeed, paleomagnetic studies of sediment cores now provide means of correlating different cores located in various areas of the Arctic, therefore providing a chronological framework for cores where no datable material is available (see Lisé-Pronovost et al.; Barletta et al., this meeting, for example). (Au)

B, D, E, G, I, J
Animal distribution; Atmospheric temperature; Bottom sediments; Carbon; Climate change; Cores; Dinoflagellata; Foraminifera; Ice cover; Mollusks; Ocean temperature; Palaeoclimatology; Palaeoecology; Palaeomagnetism; Palaeontology; Radioactive dating; Radiocarbon dating; Recent epoch; Salinity; Sea ice; Sedimentation; Temporal variations

G07, G0815, G09
Canadian Arctic waters; Canadian Beaufort Sea; Mackenzie Trough, Canadian Beaufort Sea; Northwest Passage


Evolution of sea surface conditions in the Beaufort Sea (Canada) over the last 600 years : a pre-industrial record of climate change   /   Rochon, A.   Richerol, T.
In: Québec 2008 : AGC/GAC, AMC/MAC, SEG/SGA : 400 ans de découvertes : résumés = Québec 2008 : AGC/GAC, AMC/MAC, SEG/SGA : 400 years of discoveries : abstracts. - [St. John's : GAC], 2008, v. 33, p. 145
Abstract of an oral presentation.
Indexed a PDF file available online.
ASTIS record 75568.
Languages: English
Web: http://www.gac.ca/activities/abstracts/2973_Abst...pdf
Libraries: ACU

In order to reconstruct the evolution of sea surface parameters (temperature, salinity, sea ice cover) in the Beaufort Sea for the historical and prehistorical period, and assess the impact of anthropogenic activities, a series of 3 boxcores was collected in the Mackenzie Trough as part of the CASES program. Dinoflagellate cysts (dinocyst) and freshwater palynomorphs are used as proxy indicators of sea surface conditions and freshwater input, respectively. The cores were dated using 210Pb and AMS-14C measurements, and range from 600 A.D. to the modern period, providing a multi-annual to decennial-scale resolution for our reconstructions. The highest sedimentation rate (1.2 mm/yr) is recorded at the offshore site, and it decreases gradually toward the mouth of the Mackenzie River (0.4 mm/yr). The energy at the river mouth induces a bypass of the proximal trench and shelf areas, allowing sediment deposition further offshore. We observe the passage from a heterotrophic to an autotrophic regime over the last 600 years, which we associate with increased nutrient input and/or increased open water conditions throughout the study area. The period between 1400 and 1550 A.D. is marked by low sea surface temperature, high sea ice cover and reduced primary productivity. The Little Ice Age period (1550 to 1850 A.D.) is marked by maximum dinocyst fluxes (enhanced productivity) and low sea surface temperature in surface waters. The maximum abundance of freshwater palynomorphs, accompanied by a reduction of salinity suggests increased freshwater inflow from the Mackenzie River. The industrial period (1850 A.D. and onward) is marked by a decrease of dinocyst fluxes by a factor of 2.5. These data suggest that anthropogenic activities over the last 160 years may be related to the decrease in surface productivity in the Beaufort Sea. However, there is no clear link between anthropogenic activities and the warming trend observed with the reconstructed sea surface parameters. (Au)

D, B, H, I, E, J, G
Animal distribution; Bottom sediments; Climate change; Cores ; Dinoflagellata; Environmental impacts; Glacial epoch; Ice cover; Lead; Ocean temperature; Oceanography; Palynomorphs; Plant nutrition; Primary production (Biology); Radioactive dating; Radiocarbon dating; Radionuclides; Recent epoch; Salinity; Sea ice; Sediment transport; Sedimentation; Stream flow; Suspended solids; Temporal variations

G07, G0812
Canadian Beaufort Sea; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Evolution Of Late Holocene sea-surface parameters in the Beaufort Sea area (Mackenzie Slope, Canadian Arctic) : insights from CASES 2004-804-803 cores   /   Rochon, A.   Bringué, M.
(2009 AGU Joint Assembly : the meeting of the Americas, 24-27 May 2009, Toronto, Ontario, Canada. Eos (Washington, D.C.), v. 90, no. 22, Jt. Assem. suppl., 2009, abstract PP11A-06)
Abstract of an oral presentation.
Abstracts can be found online through the AGU Meeting Abstract Database: www.agu.org/meetings/abstract_db.shtml.
ASTIS record 75657.
Languages: English
Libraries: ACU

This study aims at reconstructing late Holocene sea-surface parameters in the Beaufort Sea area (Western Canadian Arctic) on the basis of sedimentary cores collected over the Mackenzie Slope. Piston, trigger and box cores were sampled at station 803 in 2004 aboard the CCGS Amundsen (CASES) at 218 m water depth. Sedimentation at this particular location is influenced by both the Beaufort gyre and the Mackenzie River, whose sedimentary discharge is by far the largest among all other Arctic rivers. The chronology of the piston core is constrained by 4 AMS-14C dates, as the sedimentation rate in the box core is assessed from 210Pb data. We obtain a continuous composite sequence covering the last 4600 years, with a sedimentation rate of ~140 cm/kyr. Palynological data reveal that dinocyst assemblages are dominated by Operculodinium centrocarpum (mean of 43.3%), with the accompanying taxa Brigantedinium spp. (19.6%), Islandinium minutum (15.6%) and cysts of Pentapharsodinium dalei (13.7%). Four zones have been established on the basis of dinocyst relative abundances, with the following key taxa. Zone I (4600-4000 cal BP): high relative abundances of cysts of P. dalei (mean of 14.9%) and I. minutum var. cezare (up to 8.9%); zone II (4000-2600 cal BP): high abundances of Spiniferites frigidus/elongatus (up to 7.3%); zone III (2600-1600 cal BP): well-represented heterotrophic taxa Brigantedinium spp. (30.8%) and cysts of Polykrikos sp. arctic quadratus (up to 4.2%); zone IV (1600 cal BP - present): high relative abundances of I. minutum (mean of 19.8%) and cysts of P. dalei (17.3%). Quantitative reconstructions of sea-surface parameters indicate relatively stable conditions from 4600 to 1600 cal BP. Conversely, a trend of increasing summer (August) sea-surface temperature (from ~5° C to ~6° C; actual value = 6° C), increasing salinity (from ~20 to ~26 psu; modern value = 19 psu) and decreasing sea-ice cover (from ~9 to 8 month/yr; actual value = 10) is observed over the last 1600 yrs. These data are consistent with similar studies held in adjacent areas, describing the warming of Western Canadian Arctic, in comparison with a cooling Eastern Arctic. Prevailing hydroclimatic cycles in the Beaufort Sea area are also investigated on the basis of freshwater input indicators concentrations, using spectral and wavelet analysis. Potential links with the Arctic Oscillation and the Pacific Decadal Oscillation are discussed. (Au)

B, D, F, G, E, J, I
Animal distribution; Bottom sediments; Climate change; Cores; Dinoflagellata; Environmental impacts; Ice cover; Lead; Ocean currents; Ocean temperature; Palaeoclimatology; Palaeohydrology; Palynomorphs; Radioactive dating; Radiocarbon dating; Radionuclides; Recent epoch; River discharges; Salinity; Sea ice; Seasonal variations; Sedimentation; Spatial distribution; Surface properties; Temporal variations; Water masses

G07
Canadian Beaufort Sea


Holocene paleoceanography of the Northwest Passage and approaches (Baffin Bay and Beaufort Sea), Canadian High Arctic   /   Rochon, A.   Ledu, D.   Bringué, M.   de Vernal, A.   St-Onge, G.
In: International Polar Year Oslo Science Conference, 2010, 8-12 June. - [Oslo : Research Council of Norway, 2010], presentation no. LM10.2-1.4, [1] p.
Abstract of an oral presentation, taken from the USB flash drive distributed at the conference.
ASTIS record 71642.
Languages: English

A series of 6 sediments cores were collected along the main axis of the Northwest Passage and the eastern (Baffin Bay) and western (Beaufort Sea) approaches to document the evolution of sea surface conditions during the Holocene. This research was part of the Canadian-lead programs CASES, ArcticNet, PCSN, and the NSERC-IPY-SRO program. Quantitative estimates of past sea-surface conditions (summer temperature, duration of sea ice cover) were inferred from the modern analogue technique applied to dinoflagellate cyst (dinocyst) assemblages, which rely on a modern database of dinocyst assemblages containing 64 taxa and 1189 sites from the North Atlantic, North Pacific, Arctic Ocean and sub-polar seas. The chronology was established using a combination of 210Pb measurements, AMS-14C dating, and paleomagnetic secular variations of the geomagnetic field recorded in the sediments. Sedimentation rates vary between 61 and 190 cm/ka, allowing for a secular to millennial time-scale resolution. Results indicate opposite trends between the western and eastern Canadian Arctic. In the Beaufort Sea, sea surface temperatures have been increasing slightly but steadily over the last 9 ka BP, while the sea ice cover remained relatively stable. The western part of the Canadian Arctic Archipelago (CAA) was marked by high-amplitude oscillations of temperature (5°C) with intervals warmer than present around 7.5 ka BP, 5.5 ka BP and 3 ka BP. The central part of the CAA was marked by relatively stable conditions, despite a slight warming round 6 ka BP. Conversely, the eastern CAA and Baffin Bay are characterized by a cooling trend (warm/cold oscillations) since 6.5 ka BP, when sea surface temperatures were ~4°C warmer than present, accompanied by a marked reduction of the sea ice cover. We tentatively associate the opposite trends between the western and eastern Arctic to changes in the dominant mode of the Arctic Oscillation at millennial time scales. Keywords: Northwest Passage, dinoflagellate cyst, paleoceanography, paleoenvironmental reconstruction. (Au)

B, D, G, I, A
Animal distribution; Animal taxonomy; Bottom sediments; Cores; Dinoflagellata; Ice cover; Ocean temperature; Palaeogeography; Palaeohydrology; Palaeomagnetism; Palaeontology; Palynomorphs; Radioactive dating; Radiocarbon dating; Recent epoch; Sea ice; Sedimentation; Temporal variations

G0815, G07, G09
Baffin Bay-Davis Strait; Canadian Arctic Islands waters; Canadian Beaufort Sea; Northwest Passage


Écologie hivernale du réseau alimentaire microbien dans le haut arctique canadien, Baie de Franklin   /   Roy, S.   Vincent, W.F. [Supervisor]
Québec, Québec : Université Laval, 2006.
xii, 153 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR17858)
ISBN 978-0-494-17858-4
Thesis (M.Sc.) - Université Laval, Québec, Québec, 2006.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
Appendices.
References.
Contents: Chapitre 1 : Introduction générale - Chapter 2. Life in the dark : winter microbial food web structure and bacterial activity in a coastal Arctic ecosystem - Chapter 3. Wintertime limitation of bacterial production by nutrient supply (carbon, nitrogen and phosphate) in an Arctic continental shelf ecosystem - Chapitre 4 : Conclusions générale.
ASTIS record 74812.
Languages: English and French
Libraries: QQLAS OONL

The overall objective of this research was to evaluate the microbial community structure and the factors controlling carbon and energy fluxes during the winter in the arctic coastal ecosystem of Franklin Bay. This period of the year is heavily under-studied in polar ecosystems in general. Information on the composition and the activity of the microbial community during the wintertime is central to understanding the structure and functions of arctic ecosystems, and their annual carbon dynamics within the context of global climate change. Microbial abundance and production were investigated in Franklin Bay (western Canadian Arctic; 70°02'23"N, 126°18'06"W) during the solar night December-January 2003-2004 as part of the overwintering expedition of the CASES (Canadian Arctic Shelf Exchange Study) program. Vertical profiles of microbial biomass (prokaryotes, picophytoplankton and nanoflagellates) were taken weekly in conjunction with physical and chemical measurements and sampling for inorganic nutrients, dissolved organic carbon, particulate organic matter and chlorophyll a. Prokaryotic heterotrophic carbon production was estimated from 3H-leucine and 3H-thymidine uptake using both theoretical and semi-empirical conversion factors. The water column of Franklin Bay was well stratified during the sampling period. However, a hydrodynamic perturbation destabilized this stratification in late December. Small (<3 µm) autotrophic picoplankton and nanoplankton cells were observed throughout the sampling period. The abundance, biomass and metabolism of heterotrophic microbes (prokaryotes and nanoflagellates) dominated this winter microbial food web. The prokaryote abundance in the surface mixed layer (mean 1.89 ± 0.15 x 10**5 cells/ml) varied little throughout the sampling period. Incorporation rates of 3H-Ieucine and 3H-thymidine were extremely low in the surface mixed layer but always detectable (1.0 ± 0.2 pmol leu/l/h, 0.055 ± 0.006 pmol thy/l/h). Our bacterial productionestimates were comparable to those reported during winter in the Central Arctic Ocean as part of the SHEBA/JOIS drift experiment. Bacterial abundance and production did not vary significantly with depth and were independent of the physical water column structure and nutrient levels. A linear decrease (p < 0.002) in 3H-leucine incorporation rates and chlorophyll a concentrations in the surface layer were observed during the sampling period. Over the two month period, the ratio of 3H-leucine/3H-thymidine uptake averaged 30, indicating that microbial cells were putting more energy into protein synthesis rather than cell division. An estimation of the growth limitation level of bacteria by organic carbon and inorganic nitrogen and phosphorus was experimentally investigated. Unfiltered and 0.8 µm filtered samples from 3 m depth were incubated at surface temperatures (-1.5 °C) and amended with glucose as an organic carbon source, a combination of glucose and inorganic nutrients (ammonium and phosphate), and a control with no additions. Incubation with organic carbon only resulted in a significant increase in bacterial abundance and production. The addition of organic carbon and inorganic nitrogen resulted in a greater increase of bacterial abundance and production while C+N+P produced no additional stimulation relative to C+N. These results suggest that the heterotrophic bacterial community was likely limited by organic carbon energy supply, and secondly by nitrogen availability. These winter data fill an important gap in our current understanding of the seasonal dynamics of polar marine ecosystems. They show the persistence of microbial activity during winter and will allow a full annual calculation of bacterial carbon fluxes for model development and analysis within the CASES research program. (Au)

J, H, I, D, G, A
Animal distribution; Bacteria; Biological productivity; Biological sampling; Biomass; Carbon cycling; Chlorophyll; Continental shelves; Density; Dissolved organic carbon; Fluorometry; Marine ecology; Measurement; Microbial ecology; Microorganisms; Nitrogen; Ocean temperature; Particulate organic matter; Phosphorus; Photosynthesis; Phytoplankton; Plant distribution; Primary production (Biology); Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Solar radiation; Spectroscopy; Theses; Thickness; Water masses; Winter ecology

G0815
Franklin Bay, N.W.T.


Ice edge upwelling during CFL   /   Roy-Gobeil, A.   Gratton, Y.   Brouard, C.   Mundy, C.-J.   Prieur, L.
In: Circumpolar Flaw Lead System Study, International Polar Year, 2007-2008 : meeting materials, CFL All-Hands Meeting, 1-5 November 2009, Winnipeg / University of Manitoba. - [Winnipeg, Man.] : University of Manitoba, 2009, p. 44
Abstract of an oral presentation.
ASTIS record 69749.
Languages: English
Libraries: ACU

A strong ice edge upwelling event was observed in Darnley Bay between June 4 and June 7, 2008. Easterly winds >10 m/s generated a 40 m upwelling event in Darnley Bay. The Modular Ocean Model (MOM 4.1) was used to study the event. The upwelling event is well reproduced by the simulation, but the most surprising modeled feature is an eddy that travelled clockwise around Franklin. Such an eddy may very well explain some of the Canadian Arctic Shelf Exchange Study observations in Franklin Bay in December 2003. (Au)

D, E, G
Ice leads; Mathematical models; Ocean currents; Velocity; Water masses; Winds

G0815
Darnley Bay, N.W.T.; Franklin Bay, N.W.T.


Protist entrapment in newly formed sea ice in the coastal Arctic Ocean   /   Rózanska, M.   Poulin, M.   Gosselin, M.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 887-901, ill., maps)
References.
ASTIS record 65258.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.11.009
Libraries: ACU

Protist abundance and taxonomic composition were determined in four development stages of newly formed sea ice (new ice, nilas, young ice and thin first-year ice) and in the underlying surface waters of the Canadian Beaufort Sea from 30 September to 19 November 2003. Pico- and nanoalgae were counted by flow cytometry whereas photosynthetic and heterotrophic protists >=4 µm were identified and counted by inverted microscopy. Protists were always present in sea ice and surface water samples throughout the study period. The most abundant protists in sea ice and surface waters were cells <4 µm. They were less abundant in sea ice (418-3051×10**3 cells/L) than in surface waters (1393-5373×10**3 cells/L). In contrast, larger protists (>=4 µm) were more abundant in sea ice (59-821 × 10**3 cells/L than in surface waters (22-256×10**3 cells/L. These results suggest a selective incorporation of larger cells into sea ice. The >=4 µm protist assemblage was composed of a total number of 73 taxa, including 12 centric diatom species, 7 pennate diatoms, 11 dinoflagellates and 16 flagellates. The taxonomic composition in the early stage of ice formation (i.e., new ice) was very similar to that observed in surface waters and was composed of a mixed population of nanoflagellates (Prasinophyceae and Prymnesiophyceae), diatoms (mainly Chaetoceros species) and dinoflagellates. In older stages of sea ice (i.e., young ice and thin first-year ice), the taxonomic composition became markedly different from that of the surface waters. These older ice samples contained relatively fewer Prasinophyceae and more unidentified nanoflagellates than the younger ice. Diatom resting spores and dinoflagellate cysts were generally more abundant in sea ice than in surface waters. However, further studies are needed to determine the importance of this winter survival strategy in Arctic sea ice. This study clearly shows the selective incorporation of large cells (>=4 µm) in newly formed sea ice and the change in the taxonomic composition of protists between sea ice and surface waters as the fall season progresses (Au)

I, H, G, J
Algae; Animal distribution; Animal population; Animal taxonomy; Biological sampling; Chlorophyll; Cores; Cyanophyceae; Diatoms; Dinoflagellata; Flagellates; Fluorometry; Formation; Frazil ice; Grease ice; Identification; Microorganisms; Plankton; Plant distribution; Plant taxonomy; Protozoa; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Size; Spores; Thickness; Wildlife habitat

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Influence of environmental factors on the development of bottom ice protist communities during the winter-spring transition   /   Rózanska, M.   Gosselin, M.   Poulin, M.   Wiktor, J.M.   Michel, C.
(Marine ecology. Progress series (Halstenbek), v.386, July 2, 2009, p. 43-59, ill., maps)
References.
ASTIS record 71820.
Languages: English
Web: http://www.int-res.com/articles/meps_oa/m386p043.pdf
Web: doi:10.3354/meps08092

Seasonal changes in the abundance and taxonomic composition of bottom ice protists (i.e. diatoms, flagellates, and dinoflagellates) were assessed in the first-year landfast ice of Franklin Bay (Canadian Beaufort Sea) from 24 February to 20 June 2004. On each sampling day, bottom sea ice protists were collected at sites of high (>10 cm) and low (<10 cm) snow cover. The net observed growth rates of diatoms and nanoflagellates were significantly higher during the pre-bloom (24 February to 25 March) than the bloom (ca. 3 April to 23 May) period under low snow cover but were not different under high snow cover. In contrast, dinoflagellates showed relatively constant net observed growth rate before and during the bloom period under both snow covers. These results indicate that the 3 protist groups responded differently to changes in the light regime during the growth period. The decline of the protist community after the bloom period was related to a combination of factors including nitrogen deficiency and melting processes. Prior to the bloom, flagellated cells, likely heterotrophic, dominated numerically under high snow cover, whereas autotrophic protists, especially solitary diatoms, prevailed under low snow cover. During the bloom period, colonial diatoms such as Nitzschia frigida, N. promare, Navicula sp. 6, N. pelagica, and Fragilariopsis cylindrus dominated the bottom ice community irrespective of snow depth, although abundances were higher under low snow cover. The arborescent colonial N. frigida, a key species of landfast ice across circumarctic regions, was the most abundant bottom ice algal diatom throughout the entire season. During the post-bloom period, colonial and solitary diatoms declined more rapidly than nanoflagellates, suggesting that nanoflagellates, presumably heterotrophic, were better adapted to melting sea-ice conditions. Our results demonstrated that the availability of nitrate in the surface water limits the accumulation of algal biomass in the bottom horizon of Arctic landfast ice during the vernal growth season. (Au)

H, I, G, J, F, E
Algae; Animal distribution; Animal food; Animal growth; Animal population; Animal taxonomy; Biomass; Chemical oceanography; Chlorophyll; Diatoms; Dinoflagellata; Fast ice; Flagellates; Light; Microbial ecology; Microorganisms; Nitrogen; Ocean-atmosphere interaction; Phytoplankton; Plant growth; Plant nutrition; Plant taxonomy; Primary production (Biology); Sea ice; Sea ice ecology; Seasonal variations; Snow; Temporal variations

G07, G02, G0812, G07
Arctic waters; Beaufort Sea; Canadian Beaufort Sea; Eskimo Lakes, N.W.T.; Franklin Bay, N.W.T.


Denitrification activity and oxygen dynamics in Arctic sea ice   /   Rysgaard, S.   Glud, R.N.   Sejr, M.K.   Blicher, M.E.   Stahl, H.J.
(Polar biology, v. 31, no. 5, Apr. 2008, p. 527-537, ill., map)
References.
ASTIS record 65288.
Languages: English
Web: doi:10.1007/s00300-007-0384-x
Libraries: ACU

Denitrification and oxygen dynamics were investigated in the sea ice of Franklin Bay (70°N), Canada. These investigations were complemented with measurements of denitrification rates in sea ice from different parts of the Arctic (69°N-85°N). Potential for bacterial denitrification activity (5-194 µmol N/m²/day) and anammox activity (3-5 µmol N/m²/day) in melt water from both first-year and multi-year sea ice was found. These values correspond to 27 and 7%, respectively, of the benthic denitrification and anammox activities in Arctic sediments. Although we report only potential denitrification and anammox rates, we present several indications that active denitrification in sea ice may occur in Franklin Bay (and elsewhere): (1) despite sea ice-algal primary production in the lower sea ice layers, heterotrophic activity resulted in net oxygen consumption in the sea ice of 1-3 µmol/l sea ice per day at in situ light conditions, suggesting that O2 depletion may occur prior to the spring bloom. (2) The ample organic carbon (DOC) and NO3- present in sea ice may support an active denitrification population. (3) Measurements of O2 conditions in melted sea ice cores showed very low bulk concentrations, and in some cases anoxic conditions prevailed. (4) Laboratory studies using planar optodes for measuring the high-resolution two-dimensional O2 distributions in sea ice confirmed the very dynamic and heterogeneous O2 distribution in sea ice, displaying a mosaic of microsites of high and low O2 concentrations. Brine enclosures and channels were strongly O2 depleted in actively melting sea ice, and anoxic conditions in parts of the brine system would favour anaerobic processes. (Au)

H, I, J, G, D, B
Algae; Animal respiration; Bacteria; Benthos; Biochemistry; Bottom sediments; Carbon; Chlorophyll; Chromatography; Cores; Dissolved organic carbon; Fluorometry; Gases; Light; Marine ecology; Mass spectrometry; Melting; Nitrogen; Nitrogen cycling; Oxygen; Phosphorus; Photosynthesis; Primary production (Biology); Salinity; Sea ice; Sea ice ecology; Sea water; Spatial distribution; Temperature

G0815, G12, G09, G03
Arctic Ocean; Franklin Bay, N.W.T.; Greenland Sea; Qeqertarsuup Tunua, Greenland; Young Sund, Greenland


Metabolic diversity of heterotrophic bacterioplankton over winter and spring in the coastal Arctic Ocean   /   Sala, M.M.   Terrado, R.   Lovejoy, C.   Unrein, F.   Pedrós-Alió, C.
(Environmental microbiology, v. 10, no. 4, Apr. 2008, p. 942-949, ill.)
References.
ASTIS record 63905.
Languages: English
Web: doi:10.1111/j.1462-2920.2007.01513.x
Libraries: ACU

Metabolic diversity of heterotrophic bacterioplankton was tracked from early winter through spring with Biolog Ecoplates under the seasonally ice covered arctic shelf in the Canadian Arctic (Franklin Bay, Beaufort Sea). Samples were taken every 6 days from December 2003 to May 2004 at the surface, the halocline where a temperature inversion occurs, and at 200 m, close to the bottom. Despite the low nutrient levels and low chlorophyll a, suggesting oligotrophy in the winter surface waters, the number of substrates used (NSU) was greater than in spring, when chlorophyll a concentrations increased. Denaturing gradient gel electrophorisis analysis also indicated that the winter and spring bacterial communities were phylogenetically distinct, with several new bands appearing in spring. In spring, the bacterial community would have access to the freshly produced organic carbon from the early phytoplankton bloom and the growth of rapidly growing specialist phenotypes would be favoured. In contrast, in winter bacterioplankton consumed more complex organic matter originated during the previous year's phytoplankton production. At the other depths we tested the NSU was similar to that for the winter surface, with no seasonal pattern. Instead, bacterioplankton metabolism seemed to be influenced by resuspension, advection, and sedimentation events that contributed organic matter that enhanced bacterial metabolism. (Au)

I, H, J
Amino acids; Animal food; Animal physiology; Animal population; Carbohydrates; Carbon; Chlorophyll; Fluorometry; Genetics; Heterotrophic bacteria; Marine ecology; Melting; Metabolism; Microbial ecology; Plankton; Primary production (Biology); Sea ice ecology; Seasonal variations; Suspended solids

G0815
Franklin Bay, N.W.T.


Significant contribution of passively sinking copepods to downward export flux in Canadian Arctic waters   /   Sampei, M.   Sasaki, H.   Hattori, H.   Forest, A.   Fortier, L.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 146
Abstract of a Topical Session presentation.
Indexed a PDF file from the Web.
ASTIS record 67002.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

"Swimmers", metazoans caught in sediment traps, are traditionally removed from sediment trap samples before analysis to prevent overestimation of downward particle flux. However, passively sinking copepods (PSC) which have died in the water column and are caught in sediment traps should be included in the downward flux. The present study aims to estimate the temporal variability of PSC fluxes and its relative contribution to the non-living particle flux (i.e. other than swimmers). In laboratory experiments, Calanus hyperboreus, C. glacialis and Pareuchaeta glacialis that died without formalin (representative of PSC) were morphologically different from copepods that died with formalin (representative of actively intruded copepods into sediment traps) in their antennules and swimming legs. These differences were used to estimate PSC fluxes with a sediment trap in Canadian Arctic waters. The estimated PSC flux in terms of particulate organic carbon (POC) was highest in spring (19.3 mg C/m²/d), being ca. 30% of the non-living particle flux, and was ca. 5 times higher (6.4 mg C/m²/d) than the non-living particle flux in winter. The DW/POC ratio in winter for PSC was 2.0 which was one fifth of non-living particles of 11.0. Therefore, PSC could be an important food resource for pelagic and benthic heterotrophs such as Metridia longa in winter. The annual PSC flux (2.5 g C/m²/yr) was equivalent to ca. 60% of the non-living particle flux (4.2 g C/m²/yr), suggesting a substantial quantitative contribution of PSC to the vertical export of biogenic particles. (Au)

I, D, J
Animal food; Animal mortality; Benthos; Biological sampling; Carbon; Carbon cycling; Copepoda; Food chain; Seasonal variations; Sedimentation; Suspended solids; Temporal variations

G0815, G07, G09
Amundsen Gulf, N.W.T.; Beaufort Sea; Canadian Arctic waters


Significant contribution of passively sinking copepods to downward export flux in Canadian Arctic waters   /   Sampei, M.   Sasaki, H.   Hattori, H.   Forest, A.   Fortier, L.
(Limnology and oceanography, v. 54, no. 6, Nov. 2009, p.1894-1900, ill., maps)
References.
ASTIS record 68802.
Languages: English
Web: doi:10.4319/lo.2009.54.6.1894
Libraries: ACU

Typically, all undecomposed metazoans found in formalin-poisoned cups of sediment traps are considered to be active intruders (or "swimmers") and are removed to prevent an overestimation of the downward particle flux. However, intact metazoans dead before entering the trap should be included in the estimation of downward flux of carbon. Arctic copepods collected in the field were killed either by formalin to mimic death by actively swimming into the formalin-poisoned cups, or by crowding or high temperature and then preserved in formalin to simulate death before entering the trap. In the crowding and heat treatments, 64% of Calanus hyperboreus and C. glacialis and 44% of Pareuchaeta glacialis differed from copepods killed by formalin in the postmortem posture of the antennules or swimming legs. These frequencies were used to estimate the contribution of passively sinking copepods (PSCs) to the particulate organic carbon (POC) flux measured by a sediment trap moored at 70 m in the Beaufort Sea (Canadian sector of the Arctic Ocean). PSCs represented only a small fraction (<5%) of the copepods collected in the trap, thus justifying the removal of swimmers from samples to avoid a massive overestimation of fluxes. Nevertheless, PSCs contributed 36% of the overall POC flux of 6.8 g C/m²/yr, and discarding them along with the swimmers would have resulted in a significant underestimation of downward export. Given their rich carbon content (up to 50%), PSCs could be an important food resource for pelagic and benthic scavengers. (Au)

I, J, D
Animal anatomy; Animal food; Animal live-capture; Animal mortality; Biological sampling; Biomass; Carbon; Carbon cycling; Copepoda; Food chain; Identification; Marine ecology; Nitrogen; Seasonal variations; Sedimentation; Suspended solids; Zooplankton

G07, G0815, G09
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; North Water Polynya, Baffin Bay


Attenuation of the vertical flux of copepod fecal pellets under Arctic sea ice : evidence for an active detrital food web in winter   /   Sampei, M.   Forest, A.   Sasaki, H.   Hattori, H.   Makabe, R.   Fukuchi, M.   Fortier, L.
(Polar biology, v. 32, no. 2, Feb. 2009, p. 225-232, ill., maps)
References.
ASTIS record 71824.
Languages: English
Web: doi:10.1007/s00300-008-0523-z
Libraries: ACU

A variable fraction of fecal pellets produced in the epipelagic layer is intercepted and retained before reaching the bottom. We assessed fecal pellet retention in the ice-covered Beaufort Sea in early February by comparing the shape and size-frequency distribution of pellets collected by a sediment trap moored at 210 m to that produced in vitro. Appendicularian ellipsoidal and copepod cylindrical pellets made up 75 and 24% of the Xux (165 µg C/m²/day). In contrast, production (135 µg C/m²/d) was dominated by cylindrical pellets (93%). The vertical Xux of cylindrical pellets at 210 m was attenuated by 70%. Pellets >120 m in width, represented 42% of the production, but were not detected in the trap. Retention most likely resulted from coprorhexic feeding by copepods such as Metridia longa. Our observations suggest that the detritivore food web prevailing under the ice of the Arctic Ocean in winter is dominated by appendicularians feeding on pellets fragmented by copepods. (Au)

I, J, D, G, H
Animal food; Animal population; Animal taxonomy; Animal waste products; Appendicularia; Biodegradation; Biological productivity ; Carbon; Copepoda; Fast ice; Food chain; Formation; Microbial ecology; Microorganisms; Microscopes; Ocean currents; Ocean temperature; Oceanographic instruments; Salinity; Sea ice; Sea ice ecology; Seasonal variations; Sediment transport; Sedimentation; Suspended solids; Water masses; Winter ecology; Zooplankton

G0815
Franklin Bay, N.W.T.


Production and retention of biogenic matter in the southeast Beaufort Sea during 2003-2004 : insights from annual vertical particle fluxes of organic carbon and biogenic silica   /   Sampei, M.   Sasaki, H.   Makabe, R.   Forest, A.   Hattori, H.   Tremblay, J.-É.   Gratton, Y.   Fukuchi, M.   Fortier, L.
(Polar biology, v. 34, no. 4, Apr. 2011, p. 501-511, ill., maps)
References.
ASTIS record 74611.
Languages: English
Web: doi:10.1007/s00300-010-0904-y
Libraries: ACU

Regional variability in the annual fluxes of particulate organic carbon (POC) and biogenic silica (Si) at the periphery of the Mackenzie Shelf (Beaufort Sea) was investigated using eight long-term sediment traps moored at ~100-m depth. Relatively high autochthonous POC and Si fluxes were recorded in the Mackenzie Trough (4.1 and 8.9 g/m²/year respectively) and off Cape Bathurst (6.6 and 79 g/m²/year), two areas where upwelling events are frequently observed. Diatomaceous new production was minimum on the mid-slope of the Mackenzie Shelf (2.8 g C/m²/year), moderate in the Mackenzie Trough (14.5 g C/m²/year), and highest off Cape Bathurst (128.7 g C/m²/year). High annual autochthonous POC flux corresponded to high diatom production. Among sites, the vertical attenuation of the POC flux increased with diatomaceous new production. Hence, the retention of autochthonous POC in the surface layer (<100 m) was highest (95%) at the highly productive site off Cape Bathurst, intermediate (72%) in the moderately productive Mackenzie Trough, and low (4%) at the unproductive mid-slope of the shelf. Our results indicate that, on Arctic shelves, upwelling and the production of diatoms increase the fraction of the POC which is retained in the surface layer and diverted to the pelagic food web. In the relatively unproductive waters of the Arctic Ocean, biological hot spots such as the one identified off Cape Bathurst where the food web promotes retention rather than vertical export could be disproportionately important as feeding grounds for higher trophic levels. (Au)

B, I, H, J, D, G
Animal waste products; Atmospheric chemistry; Bacteria; Bathymetry; Biochemistry; Biodegradation; Biological productivity; Bottom sediments; Carbon; Carbon cycling; Chemical oceanography; Chlorophyll; Continental shelves; Diatoms; Food chain; Marine ecology; Mathematical models; Movement; Ocean currents; Ocean temperature; Ocean-atmosphere interaction; Oceanographic instruments; Oceanography; Polynyas; Primary production (Biology); Sea ice; Sea water; Seasonal variations; Sediment transport; Silica; Spatial distribution; Suspended solids; Water masses; Zooplankton

G07, G0815, G03
Amundsen Gulf, N.W.T.; Arctic Ocean; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Blowing snow studies in the Canadian Arctic Shelf Exchange Study, 2003-04   /   Savelyev, S.A.   Gordon, M.   Hanesiak, J.   Papakyriakou, T.   Taylor, P.A.
(Hydrological processes, v. 20, no. 4, 15 Mar. 2006, p. 817-827, ill.)
References.
ASTIS record 60640.
Languages: English
Web: doi:10.1002/hyp.6118
Libraries: ACU

Between mid January and early May 2004, during the Canadian Arctic Shelf Exchange Study 2003-04 expedition, we conducted a field project in which we deployed blowing-snow particle counters, visibility sensors, a FlowCapt device, snow bags, an electric field meter and other instruments related to the observation of drifting and blowing snow on first-year ice in Franklin Bay, Northwest Territories, Canada. Average snow depth was 7 cm at the beginning of the campaign and increased to 17 cm towards the end. Snow density in the first 8 cm of snow cover varied from 80 to 450 g/m³, with a median value of 240 g/m³. Basic results will be presented that relate particle counter profiles, wind speed and other data to visibility. We discuss threshold conditions for blowing snow, heat and water vapour fluxes and the electric field. Relative humidity with respect to ice was generally greater than 95% and sublimation rates are believed to have been low. (Au)

F, E, J, G
Atmospheric humidity; Blowing snow; Canadian Arctic Shelf Exchange Study; Evaporation; Instruments; Mathematical models; Measurement; Safety; Sea ice; Snow; Snow cover; Snowdrifts; Sublimation; Topography; Tundra ecology; Velocity; Visibility; Water vapour; Weather forecasting; Winds

G0815
Franklin Bay, N.W.T.


Studies of blowing snow and its impact on the atmospheric surface layer   /   Savelyev, S.A.   Miller, J. [Supervisor]   McConnell, J. [Supervisor]
Toronto : York University, 2011.
xxiii, 189 p. : ill., map ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR80554)
ISBN 978-0-494-80554-1
References.
Thesis (Ph.D.) - York University, Toronto, Ont., 2011.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74962.
Languages: English

In January-May of 2004 as a part of the Canadian Arctic Shelf Exchange Study experiment, an on-ice camp and a meteorological measurement site were established on first-year landfast ice. Standard meteorological and turbulent flux measuring instrumentation was complimented with a set of sensors dedicated to the detection of airborne particles and measurements of various parameters of snow transport. Snow cover probing and manual observations at the ship meteorological station and on the ice were performed on schedule according to the activities plan. Photoelectric particle detectors, designed and fabricated at York University, Toronto, were installed at various heights above the snow surface and provided continuous information on snow particle flux during this period. Drifting or blowing of snow in the course of the experiment was detected for 40% of the time. The criteria for blowing snow event was to last at least one hour and be separated from the previous event by greater than one hour. These criteria resulted in identification of 32 events. We propose a method of prediction of the threshold wind speed that has to be attained for blowing to begin. The method is different for three types of snow surface forming processes: solid precipitation, hoarfrost deposition and wind hardening. The aerodynamic roughness length z0m for snow covered seasonal ice was derived from pairs of wind speed and temperature profiles measured during the experiment. Its median value is 0.001 m with variations that span two orders of magnitude. This value is valid for flow with friction velocity u* greater than 0.35 m/s and less than 0.7 m/s (maximum encountered). No dependency of roughness length on suspended snow particle density in the reported range of u* was revealed. The Maximum Likelihood approach is at the base of our profile fitting procedure. The effect of random measurement errors on the result of fitting is examined. The quantitative assessment of the particle load in the multicomponent flow requires proper instruments to measure mass or volume fraction of individual constituents. Three generations of photo-electronic counters have been developed. The first two variants only counted particles without sizing them. The third variant has an ability to measure the time-of-flight of the particle through the sensor field of view. This time can be converted into estimates of the particle size if certain assumptions are made. Calibration procedures are developed that allow for accurate estimation of the minimum detected particle diameters depending on both the particle position in the sampling volume and its speed. (Au)

F, E, G
Aerodynamics; Atmospheric humidity; Atmospheric temperature; Blowing snow; Boundary layers; Crystals; Density; Electrical properties; Fast ice; Flow; Friction; Ice fog; Mathematical models; Meteorological instruments; Photography; Salinity; Sea ice; Size; Snow; Snow cover; Snow metamorphism; Snow stratigraphy; Snowdrifts; Sublimation; Surface properties; Testing; Theses; Thickness; Velocity; Visibility; Weather stations; Winds

G0815
Franklin Bay, N.W.T.


Analysis of surface roughness and morphology of first-year sea ice melt ponds : implications for microwave scattering   /   Scharien, R.K.   Yackel, J.J.
(IEEE transactions on geoscience and remote sensing, v. 43, no. 12, Dec. 2005, p.2927-2939, ill., map)
References.
ASTIS record 63275.
Languages: English
Web: doi:10.1109/TGRS.2005.857896
Libraries: ACU

Variations in wind forcing over summer first-year sea ice (FYI) melt ponds occur at hourly to weekly scales and are a significant contributor to microwave backscatter (sigma°) variability observed from spaceborne synthetic aperture radar (SAR) platforms (e.g., ENVISAT-ASAR and RADARSAT-1). This variability impairs our ability to use SAR to derive information on summer sea ice thermodynamic state and energy balance parameters such as albedo and melt pond fraction. The surface roughness contribution of FYI melt ponds in the Canadian Arctic Archipelago to like-polarized, C-band estimates is analyzed through a spectral and statistical analysis of surface wave height profiles for varying wind speeds, upwind fetch lengths, and melt pond depths. A unique derivation of melt pond surface wave height spectra is presented based on digital video of melt pond surface wave trains. Significant scale surface roughness was observed even at wind speeds of 3 m/s, resulting in small perturbation model estimates of sigma° (HH) ranging from -5 dB at 20° incidence to -22 dB at 50° incidence. Results from a multivariate linear regression analysis show that 53.5% of observed variance in sigma° (HH or VV) can be explained by wind speed, upwind fetch from melt pond edges, and melt pond depth, with no appreciable difference in the relative contribution of explanatory variables. Modeled omnidirectional sigma° as a function of wind speed and incidence angle for 100-m transects collected throughout the melt pond season act to elaborate the role of fetch and depth, as well as the modulating effect of hummocks, on sigma°. (Au)

G, F, E, D, A
Ablation; Albedo; Bathymetry; Clouds; Drainage; Fast ice; Floods; Formation; Mathematical models; Measurement; Mechanical properties; Melting; Microwave radiation; Ocean waves; Ocean-atmosphere interaction; Optical properties; Pack ice; Physical properties; Puddles; Radiation budgets; Salinity; SAR; Satellites; Sea ice; Snow; Snowpatches; Spatial distribution; Surface properties; Temperature; Temporal variations; Thermodynamics; Thickness; Topography; Velocity; Video tapes; Winds

G0815, G0813
McDougall Sound, Nunavut; Truro Island, Nunavut


Coincident high resolution optical-SAR image analysis for surface albedo estimation of first-year sea ice during summer melt   /   Scharien, R.K.   Yackel, J.J.   Granskog, M.A.   Else, B.G.T.
(Remote sensing of the cryosphere - special issue / Edited by M. Tedesco. Remote sensing of environment, v.111, no. 2-3, 30 Nov. 2007, p. 160-171, ill., maps)
References.
ASTIS record 74142.
Languages: English
Web: doi:10.1016/j.rse.2006.10.025
Libraries: ACU

The parameterization of sea ice albedo during summer, when fluctuations in the fractional coverage of melt ponds change on a variety of spatial and temporal scales, represents a significant challenge for both the modelling and remote sensing communities. Ubiquitous cloud cover in summer inhibits the use of optical sensors for providing large-scale estimates of sea ice surface albedo. C-band (5.3 GHz) Synthetic Aperture RADAR (SAR) data from ENVISAT-ASAR is compared to coincident surface climatological albedo (alpha) estimates derived from high-resolution Quickbird VIS-NIR imagery in order to demonstrate the utility of high-resolution, dual-polarized (VV, HH) SAR for detecting variations in alpha of melt pond covered landfast first-year sea ice (FYI) adjacent to Hudson Bay. Variations in ice alpha are detected from SAR imagery using the co-polarization ratio (gamma), shown to be significantly correlated (-0.81) with alpha when melt ponds are in liquid form. Results show the use of gamma represents a substantial increase in correlation to alpha when compared to conventional like-polarized SAR backscattering coefficients. A regression model demonstrates that gamma can be used as an estimator for landfast-FYI alpha to within ±5.2% provided: (1) The SAR images at a shallow enough incidence angle to induce separation between like-polarized channels; and (2) the conditions of Bragg surface scattering, characteristic of relatively shallow FYI melt ponds, is met. (Au)

G, A, F, E
Albedo; Atmospheric humidity; Atmospheric temperature; Clouds; Cores; Fast ice; Formation; Infrared remote sensing; Isotopes; Melting; Optical properties; Oxygen; Puddles; Rain; Rivers; Runoff; Salinity; SAR; Satellite photography; Sea ice; Seasonal variations; Snow; Snowmelt; Snowpatches; Spatial distribution; Surface properties; Temporal variations; Thickness; Velocity; Winds

G0814
Button Bay, Nunavut; Churchill, Cape, waters, Manitoba


Paleo-sea ice conditions of the Amundsen Gulf, Canadian Arctic Archipelago : implications from the foraminiferal record of the last 200 years   /   Schell, T.M.   Moss, T.J.   Scott, D.B.   Rochon, A.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C3, C03S02, Mar. 2008, 14 p., ill., maps)
References.
ASTIS record 64126.
Languages: English
Web: doi:10.1029/2007JC004202
Libraries: ACU

Four boxcores were collected as part of the Canadian Arctic Exchange Shelf Study (CASES) in the Amundsen Gulf at water depths of 59 m to 600 m. Data from these cores help to develop a record of changes in the oceanographic history of the area over the last 200 years, with particular reference to the indication of paleo-sea ice formation, a key element of the Arctic ecosystem. The four sites cover a range of water depths and environments to provide a basis for comparison. The benthic foraminifera of sites CA-06 (253 m water depth) and CA-18 (600 m water depth) show an increase in Arctic Surface Water associated agglutinated foraminifera over the last ~100 years (uppermost 8 to 16 cm). These are indicating a decrease in sea ice cover and in cold saline Arctic Bottom Water influence; these are similar to Canadian Arctic Archipelago postglacial faunas. This contrasts with abundant planktic foraminifera at the same stations, suggesting strong, oceanic Arctic surface influence (little freshwater) in the central Gulf. The foraminifera of sites 403B (59 m water depth) and 415B (56 m water depth), at the outermost edges of Amundsen Gulf, indicate that the present-day location of the winter flaw lead has been in place for at least the last 100 years, with foraminiferal faunas similar to those of the Beaufort Shelf. Additionally, station 415 is on an earlier Holocene shoreline that is covered with cobbles. (Au)

G, D, J, I, B, A, E, T, N, V
Amundsen (Ship); Animal distribution; Animal population; Bathymetry; Benthos; Biological productivity; Bottom sediments; Calcium carbonate; Climate change; Coast changes; Cores; Environmental impacts; Fast ice; Foraminifera; Formation; Glacial epoch; History; Hunting; Ice cover; Ice leads; Inuit; Laurentide Ice Sheet; Marine ecology; Ocean floors; Oceanographic instruments; Oceanography; Palaeoecology; Palaeogeography; Pleistocene epoch; Polynyas; Research; Sea ice; Sea level; Seasonal variations; Sedimentation; Submarine topography; Temporal variations; Water masses

G07, G0815
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Bathurst, Cape, waters, N.W.T.; Beaufort Sea; Franklin Bay, N.W.T.


Picophytoplankton and nanophytoplankton abundance and distribution in the southeastern Beaufort Sea (Mackenzie shelf and Amundsen Gulf) during fall 2002   /   Schloss, I.R.   Nozais, C.   Mas, S.   van Hardenberg, B.   Carmack, E.   Tremblay, J.-É.   Brugel, S.   Demers, S.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 978-993, ill., maps)
References.
ASTIS record 65243.
Languages: English
Web: doi:10.1016/j.jmarsys.2008.01.004
Libraries: ACU

The distribution of picophytoplankton (0.2-2 µm) and nanophytoplankton (2-20 µm) in the Beaufort Sea-Mackenzie Shelf and Amundsen Gulf regions during autumn, 2002 is examined relative to their ambient water mass properties (salinity, temperature and nutrients: nitrate + nitrite, phosphate, and silicate) and to the ratio of variable to maximum fluorescence, Fv/Fm. Total phytoplankton and cell abundances (<20 µm) were mainly correlated with salinity. Significant differences in picophytoplankton cell numbers were found among waters near the mouth of the Mackenzie River, ice melt waters and the underlying halocline water masses of Pacific origin. Picophytoplankton was the most abundant phytoplankton fraction during the autumnal season, probably reflecting low nitrate concentrations (surface waters average ~0.65 µM). The ratio Fv/Fm averaged 0.44, indicating that cells were still physiologically active, even though their concentrations were low (max Chl a = 0.9 mg/m³). No significant differences in Fv/Fm were evident in the different water masses, indicating that rate limiting conditions for photosynthesis and growth were uniform across the whole system, which was in a pre-winter stage, and was probably already experiencing light limitation as a result of shortening day lengths. (Au)

H, D, F
Biological sampling; Biomass; Chlorophyll; Fluorometry; Light; Nitrogen; Ocean temperature; Phosphorus; Photosynthesis; Phytoplankton; Plant distribution; Plant growth; Primary production (Biology); River discharges; Salinity; Sea water; Seasonal variations; Silicates; Size; Water masses

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Trifluoroacetate profiles in the Arctic, Atlantic, and Pacific Oceans   /   Scott, B.F.   Macdonald, R.W.   Kannan, K.   Fisk, A.   Witter, A.   Yamashita, N.   Durham, L.   Spencer, C.   Muir, D.C.G.
(Environmental science & technology, v. 39, no. 17, Sept. 1, 2005, p.6555-6560, ill., 1 map)
References.
Supporting information for this paper is available on-line.
ASTIS record 58220.
Languages: English
Web: doi:10.1021/es047975u
Libraries: ACU

A series of depth profiles was collected at 22 sites in the Arctic, North and South Atlantic, and Pacific Oceans to determine spatial patterns for trifluoroacetate (TFA) concentrations in the marine environment and to investigate possible natural sources of TFA. Profiles were also taken over underwater vents in the North and South Pacific and the Mediterranean Sea. At the profile sites, TFA values ranged from <10 ng/L in the Pacific Ocean to greater than 150 ng/L in the Atlantic Ocean. Samples from the Canada Basin of the Arctic Ocean exhibited variable TFA concentrations (60-160 ng/L) down to 700 m. Below this depth, in water having 14C ages exceeding 1000 years, the TFA concentrations were constant (150 ng/L). Water returning to the Atlantic through the Canadian Arctic Archipelago had constant high TFA values. Profiles from the Northern Atlantic exhibited high values at all depths but were more consistent in the Western Atlantic. The northwestern Pacific Ocean surface profile sites exhibited low TFA concentrations in the top 100 m increasing to a maximum of 60 ng/L with depth. Samples from the South Pacific Ocean site had generally low values with a few depths (>800 m) having concentrations of 50 ng/L or more. To determine if underwater vents could contribute to the TFA concentrations in the oceans, profiles were taken over three vents in the Pacific and Mediterranean Oceans. The results suggest that some deep-sea vents may be natural sources of TFA. (Au)

J, D, B
Chromatography; Composition; Geochemistry; Logistics; Marine pollution; Mass spectrometry; Measurement; Ocean temperature; Oceanography; Organofluorines; Radiocarbon dating; Salinity; Sea water; Spatial distribution; Water masses

G03, G05, G0815, G11, G09
Baffin Bay-Davis Strait; Canada Basin, Arctic Ocean; Jones Sound, Nunavut; Mediterranean Sea; Nares Strait, Greenland/Nunavut; North Atlantic Ocean; North Pacific Ocean; North Water Polynya, Baffin Bay; South Atlantic Ocean; South Pacific Ocean


Foraminifera and associated organisms on the present Mckenzie [sic] shelf/Amundsen basin, Canadian Arctic and comparison to the Antarctic faunas   /   Scott, D.B.   Schell, T.   Rochon, A.
In: Montréal 2006 résumés : Congrès annuel de l'AGC/AMC : Planète terre à Montréal = Montréal 2006 abstracts : GAC-MAC Annual Meeting : planet Earth in Montreal. - [Canada] : Geological Association of Canada, 2006, v. 31, p. 137
Abstract only.
Indexed a PDF file available online.
ASTIS record 75617.
Languages: English
Web: http://www.gac.ca/activities/abstracts/ABSTRACT_VOLUME31.pdf
Libraries: ACU

As part of the Canadian Arctic Shelf Exchange Study (CASES) over 50 surface locations were sampled for foraminifera for the first time in 40 years. These samples were collected in water depths ranging from 50 to 1100 m. The ultimate purpose of the surface samples is to calibrate the faunas to determine paleo-ice cover. Unlike previous studies smaller size fractions (>45>63 ?m [sic]; and above) instead of the usual 63 or 150 ?m [sic]; above fractions were examined. Some species not previously observed here were recorded such as Elphidiella hannai, a species commonly found along the British Columbia coast and a series of large agglutinated forms including two Komokiacea species, a group not recorded before anywhere in the Arctic Ocean. One species, Ammotium cassis, only occurred near methane seeps (a mud volcano and pingo-like features) suggesting that this species might be more tolerant to methane and provide a good proxy for past methane emissions when observed down core. In the smaller size fraction (45-63 ?m [sic]) there were a set of species in some places (the Amundsen Gulf) that provided evidence of deep Arctic water penetrating to depths as shallow as 150 m. The smaller size fraction often had more specimens per 10 cc than the 63 ?m [sic] and above fraction but less diversity. There was a fairly even division between the calcareous and agglutinated species which is the fundamental difference between the Arctic and Antarctic where the former has mostly agglutinated forms. Also because the Mckenzie Shelf has a large surface freshwater component the sedimentation rates are much higher here than the Antarctic which will provide us with higher time resolution records of the Holocene. Our main purpose was to be able to reconstruct the history of sea ice cover in Holocene. The key to this was obtaining cores and samples where there were sufficient planktonic foraminifera which are sensitive to ice cover changes. In samples deeper than 500 m there was a significant percentage of planktonics and where there was large freshwater input, there were tintinnids so that we now have two proxies for ice cover and freshwater (if there is a lot of freshwater, there isn't much ice cover). Hence we will be able to achieve our main goal of reconstructing Holocene ice cover history. (Au)

B, D, G, I, J, F
Animal distribution; Bottom sediments; Ciliata; Cores; Foraminifera; Ice cover; Palaeohydrology; Palaeontology; Recent epoch; River discharges; Sea ice; Sediment transport; Sedimentation; Size; Water masses; Wildlife habitat; Zooplankton

G07, G0815, G15
Amundsen Gulf, N.W.T.; Antarctic regions; Canadian Beaufort Sea


Benthic foraminifera in the surface sediments of the Beaufort Shelf and slope, Beaufort Sea, Canada : applications and implications for past sea-ice conditions   /   Scott, D.B.   Schell, T.   Rochon, A.   Blasco, S.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 840-863, ill., maps)
Appendix A is supplementary data that is available online.
References.
ASTIS record 65238.
Languages: English
Web: doi:10.1016/j.jmarsys.2008.01.008
Libraries: ACU

This paper presents new data on distribution patterns of modern benthic foraminifera and other microfossils from the Canadian Arctic, specifically the Beaufort Shelf and slope. The material was collected in June to August of 2004 and is the first of its kind in this area to be collected since 1970. We examined the smaller sizes (45-63 µm) as well as >63 µm and discovered that many species had been severely underrepresented in previous studies. Deep sea forms, that had been overlooked previously, were common on the shelf; two species (Elphidiella arctica and Ammotium cassis) appeared in preliminary results to be indicators of methane seepage; and it was possible to make determinations of sea-ice coverage using a combination of foraminifera and tintinnids (planktic ciliates). Our data indicated the presence of many of the same species as previous studies from this area, but improved techniques of sample processing greatly increased the number of specimens and species found (particularly the small deep sea arctic species Buliminella hensoni and Bolivina arctica) which provide much more reliable data for paleoceanographic determinations. One of the primary objectives for this work was to provide baseline data to help determine paleo-ice cover; these data cover a broad range of conditions on the Beaufort Shelf that make it possible to achieve this objective as well as improving what it is known about the assemblages on this shelf as compared to other arctic shelf areas, such as the Siberian Shelf. (Au)

I, B, D, G, J, A, Q
Animal distribution; Animal taxonomy; Benthos; Biological sampling; Bottom sediments; Ciliata; Continental shelves; Cores; Foraminifera; Ice cover; Methane; Natural gas seeps; Ocean temperature; Palaeogeography; Palaeontology; Plankton; Recent epoch; Salinity; Sea ice; Sedimentation; Suspended solids; Water masses; Wildlife habitat

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea


Modern benthic foraminifera in the surface sediments of the Beaufort Shelf, slope and Mackenzie Trough, Beaufort Sea, Canada : taxonomy and summary of surficial distributions   /   Scott, D.B.   Schell, T.   Rochon, A.   Blasco, S.
(Journal of foraminiferal research, v. 38, no. 3, July 2008, p. 228-250, ill., maps)
Contains 6 pages of plates.
Appendices.
References.
ASTIS record 66280.
Languages: English
Web: doi:10.2113/gsjfr.38.3.228
Libraries: ACU

This paper reviews some new data on distribution patterns of modern benthic foraminifera and related organisms from the Canadian Arctic, specifically the Beaufort Shelf and slope. The smaller sizes - 45-63 µm as well as >63 µm - were examined, and it was discovered that many species had either been overlooked altogether or severely underrepresented in previous studies. Not surprisingly, the deep-sea forms in particular had been overlooked even though they are present in the shallow shelf sediments in significant numbers. Although the data show many of the same species as previous studies, improved techniques of sample processing greatly increased the numbers of specimens and species found, enhancing the spatial and faunal relationships. These new data change the known faunas and will allow a much more precise indication for paleoenvironmental studies than was previously available. However, the major focus of this paper is taxonomy and illustration of most of these species to update the taxonomy last done in the 1990's. One new species is reported, Cyclogyra distincta Cole and Scott, and Komokiacea (excluding Rhizammina algaeformis Brady) are reported from the Arctic for the first time as well as a southern immigrant, Elphidiella hannai (Cushman and Grant), which appears to thrive in methane-rich environments in the Arctic. (Au)

I, B, J, E, D, A
Adaptation (Biology); Animal anatomy; Animal distribution; Animal ecology; Animal taxonomy; Benthos; Biological productivity; Bottom sediments; Chemical oceanography; Climate change; Cores; Fluorometry ; Foraminifera; Marine ecology; Methane; Mud volcanoes; Ocean temperature; Palaeoecology; Palaeontology; Physical properties; Recent epoch; Runoff; Salinity; Sedimentation; Submarine topography; Winds; Zooplankton

G07, G0815, G15, G141, G0812, G03, G09
Amundsen Gulf, N.W.T.; Antarctic waters; Arctic Ocean; Baffin Bay-Davis Strait; Canadian Beaufort Sea; Karskoye More; Kugmallit Bay, N.W.T.; Lancaster Sound, Nunavut; Mackenzie River, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea; Ross Sea, Antarctic regions


Historical variability - paleoclimates   /   Scott, D.B.   Rochon, A.   Schell, T.M.   St. Onge, G.   Blasco, S.   Bennett, R.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 8, p. 143-157, ill., maps
References.
ASTIS record 67491.
Languages: English
Libraries: ACU

... This part of the CASES project focused on the calibration and use of micropaleontological and sedimentological proxies for paleoceanographic studies which could be related to paleoclimate and millennial/decadal changes in sea ice cover. ... a large suite of samples were collected between 2003 and 2005 using boxcores (surface and short cores) for the last 100 years and piston cores (representing longer records which take us back to the last glacial period). The proxies which were of most use to this study were microfossils: a) Dinoflagellates and Pollen. ... [dinoflagellates] produce highly resistant cysts that are fossilizable and representative of the seawater conditions in which they were formed. ... cysts constitute excellent indicators of palaeo-sea ice conditions. ... [they] provide quantitative estimates of sea surface parameters such as temperature, salinity and sea ice cover. ... [pollen grains] provide a proxy for terrestrial vegetation, and therefore the continental climate adjacent to the water body being sampled; b) Foraminifera-planktonic and Benthic, Stable Isotopes (oxygen-18 and carbon-13). Foraminifera are single-celled organisms that are found throughout the water column and at the water-sediment interface (pelagic-benthic). ... c) Tintinnids. These are ciliates that live in the surface waters. ... Their presence indicates brackish environment and/or an abundance of suspended particulates. ... d) Thecamoebians. These are freshwater rhizopods (the freshwater equivalent to foraminifera) and provide an indicator of particles transported by freshwater into the marine system; d) Diatoms .... because they are composed of silica it was almost impossible to separate them out from the surrounding silt sediment .... This work has several implications: a) We can, using micropaleontological and sedimentological proxies, delineate several distinct faunal/floral/sedimentological zones within the study area. This provides information on the distribution ofmicropaleontological proxies, which in turn allows us to determine paleoceanographical conditions, sea ice cover, freshwater input, and glacial activity for the Holocene period. b) Atlantic deep water seems to be restricted to the deep water core, as well as to a very narrow interval in early postglacial times when there were calving icebergs. c) We can identify periods of higher and lower sea-ice cover, higher freshwater input, early glacial movement, as well as recent changes. d) We can now begin to determine a glacial history for the Beaufort Shelf and its relation to glacial activity further South, with Glacial ice retreating much earlier in marine areas than on land (at least near Banks Island). e) With the more recent data on sea-ice cover, we can also begin to compare present conditions with pre-industrial and Holocene history .... [Piston core locations: Beaufort Sea, PC 750: 71.20°N, 134.08°W; Amundsen Gulf, PC 124: 71.24°N, 126.46°W.] (Au)

B, E, G, D, I, H, A, F
Animal distribution; Bottom sediments; Ciliata; Cores; Diatoms; Dinoflagellata; Foraminifera; Glacial epoch; Glaciers; Ice cover; Icebergs; Lead; Magnetic properties; Ocean temperature; Offshore seismic surveys; Palaeoclimatology; Palynology; Plant distribution; Protozoa; Radioactive dating; Radiocarbon dating; Recent epoch; Salinity; Sea ice; Sediment transport; Sedimentation; Size; Soil profiles; Sonar; Temporal variations; Water masses; X-rays

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Mackenzie Trough, Canadian Beaufort Sea


Foraminiferal assemblage changes over the last 15,000 years on the Mackenzie-Beaufort Sea slope and Amundsen Gulf, Canada : implications for past sea ice conditions   /   Scott, D.B.   Schell, T.   St-Onge, G.   Rochon, A.   Blasco, S.
(Paleoceanography, v. 24, PA2219, June 2009, 20 p., ill., maps)
References.
ASTIS record 67473.
Languages: English
Web: doi:10.1029/2007PA001575
Libraries: ACU

Two cores, one from the Beaufort Sea Slope at 1000 m water depth (core 750) and one from the Amundsen Gulf at 426 m (core 124), were collected to help determine paleo-ice cover in the Holocene and late glacial of this area. [Piston core locations: PC 750: 71.20°N, 134.08°W; PC 124: 71.24°N, 126.46°W.] Site 750 is particularly sensitive to changes in paleo-ice cover because it rests beneath the present ice margin of the permanent Arctic ice pack. Core 124 was sampled just in front of the former glacier that moved out into the Amundsen Gulf and started to recede about 13 ka B.P. Both cores have a strong occurrence of calcareous foraminfera in the upper few centimeters but these disappear throughout most of the Holocene suggesting more open water in that time period than present. In the sediments representing the end of the last glacial (dated at ~11,500 to 14,000 calibrated years B.P. (cal B.P.)) a calcareous fauna with an abundant planktic foraminiferal fauna suggests a return to almost permanent ice cover, much like the central Arctic today. Together with the foraminifera there was also abundant ice rafted debris (IRD) in both cores between 12,000 cal B.P. and ~14,000 cal B.P. but those units are of different ages between cores, suggesting different events. The IRD is in both cores appears to have the same magnetic and chemical signals, but their origins cannot be determined exactly until clay mineralogy is completed. There is abundant organic debris in both cores below the IRD units: the organics in core 750 are very diffuse and not visually identifiable, but the organic material in core 124 is clearly identifiable with terrestrial root fragments; these are C-14 dated at over 37,000 years B.P. This is a marine unit as it also has glacial front foraminifera in the sediment with the organic debris that must have been originating from subglacial streams. The seismic and multibeam data both indicate glaciers did not cross the core 124 site. (Au)

B, D, G, I, J, F, A
Animal distribution; Benthos; Biological productivity; Bottom sediments; Carbon; Carbonates; Cesium; Cores; Glacial epoch; Glaciers; Ice cover; Isotopes; Lead; Magnetic properties; Mass spectrometry; Nitrogen; Ocean temperature; Offshore seismic surveys; Palaeontology; Photography; Pleistocene epoch; Radioactive dating; Radiocarbon dating; Recent epoch; Salinity; Sea ice; Sediment transport; Sedimentation; Size; Suspended solids; Temporal variations; Water masses; X-rays; Zooplankton

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Winter-spring feeding and metabolism of Arctic copepods : insights from faecal pellet production and respiration measurements in the southeastern Beaufort Sea   /   Seuthe, L.   Darnis, G.   Riser, C.W.   Wassmann, P.   Fortier, L.
(Polar biology, v. 30, no. 4, Mar. 2007, p. 427-436, ill., maps)
References.
ASTIS record 63268.
Languages: English
Web: doi:10.1007/s00300-006-0199-1
Libraries: ACU

Faecal pellet production (FPP) and respiration rates of Calanus glacialis, C. hyperboreus and Metridia longa were measured under land-fast ice in the southeastern Beaufort Sea during the winter-spring transition (March-May 2004) prior to the phytoplankton spring bloom. Despite different overwintering and life cycle strategies and remaining low concentrations of suspended chlorophyll a and particulate organic matter, all species showed increasing FPP rates in spring. A corresponding increase in respiration was only observed in C. glacialis, while respiration remained constant in C. hyperboreus and M. longa. In C. glacialis and C. hyperboreus calculated ingestion covered respiratory expenditures. The constancy of the oil sac volume in M. longa suggests that the animals fed during winter-spring. Pre-bloom grazing as shown here seems to acclimate the copepod populations physiologically for the upcoming high feeding season, so that they are able to resume maximum grazing and reproduction as soon as the phytoplankton bloom is initiated. (Au)

I, H, G, J, D, A
Adaptation (Biology); Algae; Animal behaviour; Animal food; Animal physiology; Animal reproduction; Animal respiration; Animal waste products; Biological productivity; Biomass; Carbon; Chlorophyll; Continental shelves; Copepoda; Fast ice; Ice cover; Measurement; Metabolism; Particulate organic matter; Phytoplankton; Polynyas; Primary production (Biology); Sea ice; Sea ice ecology; Seasonal variations; Zooplankton

G081, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Franklin Bay, N.W.T.


Frontal structures associated with coastal upwelling and ice-edge subduction events in southern Beaufort Sea during the Canadian Arctic Shelf Exchange Study   /   Sévigny, C.   Gratton, Y.   Galbraith, P.S.
(Journal of geophysical research, v.120, no. 4, April 2015, p.2523-2539, ill., maps)
References.
ASTIS record 80989.
Languages: English
Web: doi:10.1002/2014JC010641
Libraries: ACU

The near-surface temperature structure in the southeastern Beaufort Sea is shown to have been largely dependent on frontal dynamics in spring 2004, which may be typical for the region. Easterly wind events generated coastal upwelling along the Cape Bathurst peninsula; a recurring event in that area. Further west, a large mesoscale anticyclone simultaneously developed and subsequently controlled the sea-surface circulation in the central Amundsen Gulf. Sharp temperature and density fronts were created at the surface at both eastern and western ends of the domain. Sampling north of Cape Bathurst and Cape Parry showed evidence of frontal intensification. Frontal features were detected near the 50–200 m isobaths, at the mouth of the gulf, where density-compensated near-surface intrusions driven by agesotrophic vertical circulation were identified. These warm water tongues intruded into the outcropping isopycnal layers, which dipped down between 5 and 25 m over the Mackenzie Shelf. They then crossed the density surfaces with an inverse slope consistent with N/f as predicted for quasi-geostrophic flows. The front event ended prior to the breakup of the landfast-ice bridge in late June with sea-surface temperature undergoing quick and widespread changes throughout the Amundsen Gulf. (Au)

D, E, G, J
Biological productivity; Breakup; Chemical oceanography; Data buoys; Density; Fast ice; Hydrography; Measurement; Melting; Ocean currents; Ocean temperature; Oceanographic instruments; Oxygen; Salinity; Satellite photography; Sea ice; Sea level; Surface temperature; Water masses; Winds

G0815, G07
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Parry, Cape, waters, N.W.T.


An annual study of inorganic and organic nitrogen and phosphorus and silicic acid in the southeastern Beaufort Sea   /   Simpson, K.G.   Tremblay, J.-É.   Gratton, Y.   Price, N.M.
(Journal of geophysical research, v.113, no. C7, C07016, July 2008, 16 p., ill., map)
References.
ASTIS record 65874.
Languages: English
Web: doi:10.1029/2007JC004462
Libraries: ACU

Water column samples from the Mackenzie Shelf, the Beaufort Sea, and the Amundsen Gulf were obtained during 2003-2004 to investigate nutrient dynamics in an Arctic ecosystem influenced by a large river and flaw lead polynya. Nutrient inventories in the upper water column showed a significant seasonal drawdown of nitrate ((NO3)-) and silicic acid (Si(OH)4) (1:1.75 mol/mol) and subsequent accumulation of nitrite ((NO2)-) and ammonium ((NH4)+). Dissolved organic nitrogen and phosphorus concentrations (DON and DOP) were elevated in surface waters during the time of peak phytoplankton growth (bloom and postbloom phases) and covaried in a 17:1 molar ratio. Vertical profiles showed the typical middepth maxima in (NO3)-, (PO4)3-, and Si(OH)4 at salinity 32-33.1. The concentration of DOP (0.76 ±0.27 µmol P/L) was also 2 times higher in this layer compared to the surface average and inversely correlated with the water mass tracer N* [N* = (((NO3)-) - 16 × ((PO4)3-) + 2.9) × 0.87], suggesting that Pacific-derived waters were a source of the enrichment. Below the mixed layer, DON was generally constant with depth, although averaged profiles (like those of urea) suggested the presence of subsurface maxima at 50 m and between 250 and 300 m. Regeneration ratios varied with depth and were approximately 9.0 mol -O2/mol (NO3)- and 122.5 mol -O2/mol (PO4)3- in shallow Pacific-derived waters (halocline layer) and 17.4 and 193.5 in deep Atlantic waters (Atlantic layer), respectively. Deep waters of the Amundsen Gulf contained an excess of 1.7 µmol (NO3)-/L, 0.12 µmol (PO4)3-/L, and 6.2 µmol Si(OH)4/L and a deficit in O2, relative to waters of similar density in the Beaufort Sea, in proportions consistent with the remineralization ratios derived from oxygen-nutrient regressions. Enhanced export of particulate matter from the overlying polynya and subsequent remineralization at depth are hypothesized to create this nutrient enrichment. (Au)

H, D, F, J
Algae; Ammonium; Biological sampling; Biomass; Chemical oceanography; Chlorophyll; Density; Diatoms; Marine ecology; Nitrogen; Ocean temperature; Oxygen; Phosphorus; Phytoplankton; Plant growth; Plant nutrition; Polynyas; Primary production (Biology); River discharges; Rivers; Salinity; Seasonal variations; Silica; Spatial distribution; Water masses

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.


Nutrient dynamics in the western Canadian Arctic. I. New production in spring inferred from nutrient draw-down in the Cape Bathurst Polynya   /   Simpson, K.G.   Tremblay, J.-É.   Price, N.M.
(Marine ecology. Progress series (Halstenbek), v.484, June 12, 2013, p. 33-45, ill., maps)
References.
ASTIS record 80110.
Languages: English
Web: http://www.int-res.com/abstracts/meps/v484/p33-45/
Web: doi:10.3354/meps10275
Libraries: ACU

Ice-retreat from the Cape Bathurst Polynya occurred in late May and early June 2004, and was quickly followed by a decrease in dissolved nutrient concentration at the sea surface. Concentration plots of NO3 versus PO4, and Si(OH)4 versus NO3 showed the ratios of nutrient uptake in the surface layer were in proportions expected for diatom growth (N:P 13.1:1; Si:N 1.8:1) and that water-column NO3 was depleted before PO4 and Si(OH)4. The temporal changes in integrated nitrate, phosphate and silicate concentrations were well described by logistic models that showed maximum consumption rates of 11.8, 0.82, and 17.8 mmol/m²/d, respectively, and a total seasonal draw-down of 210 ± 19 mmol NO3/m². If we include estimates of NO3 supply by advection, nitrification and freshwater dilution, then the amount of NO3 consumed could be 25-33% higher. Uptake of NO3 above the 1% isolume was balanced by an equivalent (94%) increase in particulate N over a 15 d period beginning at ice break-up. Thus, the amount of particulate spring new production associated with NO3 disappearance was estimated to be 16.1 ± 1.5 g C/m². (Au)

D, H, E, G, J
Ammonium; Biological productivity; Biological sampling; Diatoms; Dissolved organic carbon; Ice cover; Nitrogen cycling; Phosphorus; Phytoplankton; Plant nutrition; Polynyas; Primary production (Biology); Sea ice; Seasonal variations; Silicates

G07, G0815
Bathurst, Cape, waters, N.W.T.; Franklin Bay, N.W.T.


Nutrient dynamics in the western Canadian Arctic. II. Estimates of new and regenerated production over the Mackenzie Shelf and Cape Bathurst Polynya   /   Simpson, K.G.   Tremblay, J.-É.   Brugel, S.   Price, N.M.
(Marine ecology. Progress series (Halstenbek), v.484, June 12, 2013, p. 47-62, ill., maps)
References.
ASTIS record 80113.
Languages: English
Web: http://www.int-res.com/abstracts/meps/v484/p47-62/
Web: doi:10.3354/meps10298
Libraries: ACU

Uptake of 15N-labelled nitrate, ammonium, and urea was measured over a quasi-annual cycle in the Cape Bathurst Polynya in the Amundsen Gulf and on the Mackenzie Shelf, during the Canadian Arctic Shelf Exchange Study (CASES) in 2003 and 2004. Before the phytoplankton bloom and in autumn, nitrogen uptake was slow, representing less than 5% of annual consumption. Uptake rates increased exponentially after ice retreat and within 3 wk reached a maximum of 38.6 mmol N/m²/d. During spring, NO3- uptake supported new production of 166 mmol N/m² and f-ratios rose from 0.1-0.2 to 0.6-0.9. Filter fractionation showed that GF/F filters retained 93.1 ± 1.3% of the 15N incorporated into particulate matter, suggesting that phytoplankton were responsible for the majority of the N uptake. Although free-living bacteria took up relatively more 15N in autumn and in the lower part of the euphotic zone than phytoplankton, their assimilation of inorganic N had little effect on water column integrated f-ratios or new production. Urea supplied almost half the N assimilated by phytoplankton annually and about 80% of the regenerated production during the spring bloom. Total new production, estimated from water column integrated 15N-nitrogen uptake rates and linear models that interpolated rates over unsampled periods, was 342-415 mmol N/m²/yr. Total annual N production for the region was 1.24-1.48 mol N/m²/yr. (Au)

D, H, E, G, J
Ammonium; Bacteria; Biological productivity; Biological sampling; Chlorophyll; Dissolved organic carbon; Fluorometry; Ice cover; Light; Mass balance; Mathematical models; Nitrogen; Nitrogen cycling; Ocean temperature; Phosphorus; Phytoplankton; Plant nutrition; Polynyas; Primary production (Biology); Sea ice; Seasonal variations

G07, G0815, G03
Amundsen Gulf, N.W.T.; Arctic Ocean; Bathurst, Cape, waters, N.W.T.; Franklin Bay, N.W.T.


Nutrient dynamics and nitrogen-based production in the western Canadian Arctic Ocean   /   Simpson, K.G.F.   Price, N.M. [Supervisor]
Montreal : McGill University, 2007.
xvii, 124 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR51343)
ISBN 978-0-494-51343-9
References.
Thesis (M.Sc.) - McGill University, Montreal, Quebec, 2007.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74784.
Languages: English
Web: http://www.collectionscanada.gc.ca/obj/thesescanada/vol2/002/MR51343.PDF
Libraries: OONL

Inclement climate conditions have made the Arctic Ocean logistically difficult to study, and thus, our historical knowledge of Arctic Ocean processes are limited. Recent observations indicate rapid and abrupt changes in climate. These changes are thought to includes rising temperatures, increase storm activity, altered freshwater balance and a notable decrease in the concentration and extent of sea ice covering the Arctic Ocean. Increasing awareness of these changing conditions and our poor knowledge of how the physical environment influences carbon fluxes, planktonic productivity and biogeochemical cycling have lead to international efforts to address these questions. The data presented here addresses biogeochemical cycling and phytoplankton primary production in the pelagic ecosystem. Given the pace of environmental change in the arctic (rapid ice retreat, record minimum ice extents, and temperature rise) and the relatively little historical data that is available for the region, the data presented here can also be used as a baseline data set from which predictions can be made and future observations can be compared. Conducted as part of the Canadian Arctic Shelf Exchange Study (CASES), this thesis provides a current review of nutrient dynamics and cycling, and estimates of annual new and net primary production for the Mackenzie Shelf, the Amundsen Gulf and the Cape Bathurst polynya in the southeastern Beaufort Sea in the Canadian Arctic Ocean. (Au)

H, D, F, J, G
Algae; Ammonium; Bacteria; Biological sampling; Biomass; Chemical oceanography; Chlorophyll; Climate change; Density; Diatoms; Environmental impacts; Ice cover; Isotopes; Marine ecology; Melting; Nitrogen; Nitrogen oxides; Ocean temperature; Oxygen; Phosphorus; Phytoplankton; Plant growth; Plant nutrition; Polynyas; Primary production (Biology); River discharges; Rivers; Salinity; Sea ice; Seasonal variations; Silica; Silicates; Spatial distribution; Temporal variations; Theses; Water masses

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie River, N.W.T.


High-resolution physical and magnetic properties of rapidly deposited layers associated with landslides, earthquakes and floods   /   St-Onge, G.   Chapron, E.   Guyard, H.   Rochon, A.   Lajeunesse, P.   Locat, J.   Scott, D.   Stoner, J.S.   Hillaire-Marcel, C.
In: Comptes rendus : 4e conférence canadienne sur les géorisques : des causes à la gestion, 20 au 24 mai 2008, Université Laval Québec = Proceedings : 4th Canadian Conference on Geohazards : from causes to management, May 20-24th, 2008 / Edited by J. Locat et al. - Laval, Québec : Canadian Geotechnical Society, Engineering Geology Division, 2008, [10] p., ill., map
(GEOTOP contribution, no. 2008-001)
Indexed a PDF file from the Web.
References.
ASTIS record 70703.
Languages: English
Web: http://www.landslides.ggl.ulaval.ca/geohazard/technologies/st_onge.pdf

During the last decade, major technological advances were made regarding the continuous measurement of the physical and magnetic properties of sediment cores. Rapid and non destructive analysis can now be performed continuously on either marine or lacustrine sediments with a downcore resolution of up to 100 µm. Such a resolution in conjunction with the possibility of acquiring high-resolution digital classical or X-ray images of sediment cores allow new opportunities for the identification and characterization of sediment layers associated with natural hazards such as landslides, earthquakes or floods. In this paper, we illustrate how the continuous physical and magnetic properties of the sediments can be combined with classical sedimentological analyses to identify and date rapidly deposited layers triggered by landslides, earthquakes and floods. We provide an overview of several recent examples from marine and lacustrine Holocene sedimentary records from Eastern and Arctic Canada, Hudson Bay and Strait, Patagonia and the Alps. (Au)

B, A, D, F
Bottom sediments; Cores; Coring; Earthquakes; Floods; Geochemistry; Geological time; Instruments; Landslides; Magnetic properties; Measurement; Palaeomagnetism; Physical properties; Risk assessment; Sedimentation; X-rays

G0814, G0815, G11, G0825
Alps, Europe; Amundsen Gulf, N.W.T.; Chile; Hudson Bay; Hudson Strait, Nunavut/Québec; Saguenay, Rivière, Québec; St. Lawrence Estuary, Québec


Geomagnetic field variability in the western Canadian Arctic since the last deglaciation   /   St-Onge, G.   Lise-Pronovost, A.   Barletta, F.   Channell, J.E.   Brachfeld, S.A.   Polyak, L.V.   Darby, D.A.   Rochon, A.   Scott, D.B.
(2009 AGU Fall Meeting, 14-18 December, San Francisco. Eos (Washington, D.C.), v. 90, no. 52, suppl., 2009, abstract GP13B-0773)
Abstract of a poster presentation (GP13B-0773).
Abstracts can be found online through the AGU Meeting Abstract Database: www.agu.org/meetings/abstract_db.shtml.
ASTIS record 75660.
Languages: English
Libraries: ACU

Several piston cores (HLY0501-05JPC, -06JPC, -08JPC and 2004-804-803, -124, -250, -650, -750) were recently collected in the western Canadian Arctic and Arctic Alaskan margin as part of major international scientific programs such as CASES (Canadian Arctic Shelf Exchange Study), ArcticNet and HOTRAX (Healy-Oden Trans Arctic Expedition). Due to the seafloor imaging and subbottom profiling capabilities of the deployed ice-breakers (CCGS Amundsen and USCCG Healy), the coring sites were carefully selected for high sediment accumulation areas not affected by mass wasting events nor by ice scouring. The sedimentological, physical and magnetic properties of these piston cores in conjunction with AMS-14C dating reveal that these cores span the last deglaciation to the present with sedimentation rates as high as 350 cm/ka. Here we highlight key paleomagnetic secular variations and relative paleointensity findings from selected cores collected off the Arctic Alaskan margin, the Mackenzie delta and in the Amundsen Gulf in order to synthesize geomagnetic field variability in the western Canadian Arctic since the last deglaciation. (Au)

B, D, A, F
Bottom sediments; Cores; Deglaciation; Geomagnetism; Glacial epoch; Magnetic properties; Marine geology; Palaeomagnetism; Physical properties; Radiocarbon dating; Recent epoch; Sedimentation; Seismic surveys; Sonar; Submarine topography; Temporal variations

G04, G07, G0815
Alaskan Beaufort Sea; Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Chukchi Sea


Paleomagnetism near the North Magnetic Pole : a unique vantage point for understanding the dynamics of the geomagnetic field and its secular variations   /   St-Onge, G.   Stoner, J.S.
(The changing Arctic Ocean : special issue on the International Polar Year (2007-2009). Oceanography (Washington, D.C.), v. 24, no. 3, Sept. 2011, p. 42-50, ill., map)
(GEOTOP contribution, no. 2011-0005)
References.
ASTIS record 74914.
Languages: English
Web: doi:10.5670/oceanog.2011.53
Libraries: ACU

Along with the dramatic decrease in global geomagnetic field intensity, recent observations demonstrate that the geomagnetic field in the Arctic has dramatically changed over the last century. This change is best illustrated by the recent migration of the North Magnetic Pole (which has been in the Canadian Arctic for the last 400 years) into the Arctic Ocean. Because historical records are short, paleomagnetic studies are needed to put these recent Arctic geomagnetic changes into a proper temporal context. This paper presents an overview of Arctic geomagnetism, paleomagnetism, and recent efforts to move our understanding forward by looking at recent or emerging high-resolution Holocene records from the Low and the High Arctic. These paleomagnetic records attest to the unique nature of the geomagnetic field in the High Arctic. They also highlight how the Arctic, and especially the High Arctic, is a unique vantage point for studying geodynamo processes associated with the tangent cylinder model of convective flow within Earth's core that could lead to differences in the behavior of the geomagnetic field observed at Earth's surface, and possible relationships to paleomagnetic secular variations at mid-latitudes. (Au)

B
Bottom sediments; Cores; Geomagnetism; Palaeomagnetism; Pleistocene epoch; Recent epoch; Temporal variations

G03, G0813, G02
Arctic regions; Beaufort Sea; Canadian Arctic Islands; Chukchi Sea; North American Arctic; North Pole; United States


Spatiotemporal occurrence of summer ichthyoplankton in the southeast Beaufort Sea   /   Suzuki, K.W.   Bouchard, C.   Robert, D.   Fortier, L.
(Polar biology, v. 38, no. 9, Sept. 2015, p.1379-1389, ill., maps)
References.
Indexed manuscript prior to publication.
ASTIS record 80810.
Languages: English
Web: doi:10.1007/s00300-015-1701-4
Libraries: ACU

Current trends of fish communities in the interior Arctic Ocean are largely unknown, whereas more fishes of boreal origin are reported from the Chukchi and Barents Seas recently. To assess variability in species composition and spatiotemporal occurrence in ichthyoplankton in the southeast Beaufort Sea, we sampled larval and juvenile fish using square-conical nets in the upper water column (<100 m) from June to September between 2002 and 2011. Gadidae consisting of Boreogadus saida and Arctogadus glacialis numerically accounted for >75% of total catches every month. Cottidae and Liparidae usually followed Gadidae, together representing 9-94% of non-gadid species in number. The majority of dominant and subdominant species occurred ubiquitously through the sampling area, whereas Gymnocanthus tricuspis (Cottidae), Liparis gibbus (Liparidae), and Leptoclinus maculatus (Stichaeidae) occurred abundantly on the Mackenzie Shelf. In contrast, Triglops nybelini (Cottidae) was frequently found in the Amundsen Gulf, which was characterized by higher salinities (>25). Exceptional species composition was observed in September 2011, when Ammodytes hexapterus (Ammodytidae) numerically accounted for 67% of non-gadid species. In the southeast Beaufort Sea, summer ichthyoplankton are characterized by the overwhelming dominance of Arctic gadids as well as the frequent occurrence of Arctic cottids and liparids. However, the sudden and frequent occurrence of A. hexapterus may be a first sign of significant changes in fish communities in the interior Arctic Ocean. (Au)

D, E, I, J
Animal distribution; Animal food; Animal growth; Biological sampling; Climate change; Environmental impacts; Fish larvae; Fishes; Gadidae; Maps; Marine ecology; Ocean temperature; Runoff; Salinity; Sand lances; Seasonal variations; Temporal variations

G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Estimation of suspended particulate matter concentrations in the Beaufort Sea from MERIS using support vector machines   /   Tang, S.   Michel, C.   Larouche, P.
In: ArcticNet programme 2009 : annual scientific meeting, 8-11/12/2009, Victoria, B.C. = ArcticNet programme 2009 : réunion scientifique annuelle, 8-11/12/2009, Victoria, B.C. - [Québec, Québec] : ArcticNet, 2009, p. 137
Abstract of a poster presentation.
Indexed a PDF file from the Web.
ASTIS record 73196.
Languages: English
Web: http://www.arcticnetmeetings.ca/docs/asm2009_programme_long.pdf
Libraries: ACU

Bio-optical properties in polar waters are significantly different from those in mid-latitude and low-latitude waters. The Beaufort Sea has unique bio-optical characteristics because it receives the largest amount of suspended sediments compared to other Arctic shelves. Moreover, high colour dissolved organic matter (CDOM) absorption and pigment packaging effects reduce the precision of traditional ocean colour algorithms. Analysis of in-situ optical data and suspended particulate data collected during the Canadian Arctic Shelf Exchange Study (CASES) in summer 2004, shows that the sensitive bands which have the best correlation with suspended particulate matter (SPM) concentrations change with the increase in SPM concentrations. When the mean SPM concentration is 0.47 g/m³, the Rrs(443) shows the highest correlation with the SPM concentration, nevertheless, when the mean SPM concentration reaches 1.8 g/m³, the most sensitive reflectance is at 560 nm. The goal of this work is to investigate the feasibility of using a new universal approximator - support vector machines (SVMs) - as the nonlinear transfer function between SPM concentration and remote sensing reflectances (Rrs(443), Rrs(560) and Rrs(681)) to estimate SPM concentrations in the Beaufort Sea. The study results show that the performance of the SVM is superior to the counterparts of Clark's algorithm and standard MERIS algorithm which is based on artificial neural network (ANN). The algorithm based on the SVM is applied to MERIS satellite data on July 17-18, 2007. The distributions of SPM concentrations obtained show that the algorithm based on SVMs could be a useful tool for obtaining SPM information in the Beaufort Sea. (Au)

D, A
Carbon; Colored dissolved organic matter; Electronic data processing; Oceanography; Optical properties; Remote sensing; Satellite photography; Suspended solids

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Regional algorithms for remote-sensing estimates of total suspended matter in the Beaufort Sea   /   Tang, S.   Larouche, P.   Niemi, A.   Michel, C.
(International journal of remote sensing, v. 34, no. 19, 2013, p.6562-6576, ill., maps)
References.
ASTIS record 79614.
Languages: English
Web: doi:10.1080/01431161.2013.804222
Libraries: ACU

The large and variable riverine inflow to Arctic continental shelves strongly influences their chemical, biological, and optical properties. The Beaufort Sea receives the largest amount of suspended sediments amongst all Arctic shelves, with sediment-laden Mackenzie river waters strongly influencing bio-optical properties on the shelf. Here, we developed two regional algorithms for the estimation of total suspended matter (TSM) concentration using Medium Resolution Imaging Spectrometer (MERIS) spectral bands, based on in situ optical and suspended particulate data collected in the summer during the Canadian Arctic Shelf Exchange Study (CASES) in 2004 and during the Arctic Coastal Ecosystem Study (ACES) in 2010. The band ratio (where Rrs is remote-sensing reflectance) Rrs,560/R rs,490 was best correlated with low TSM concentrations (less than 3.0 g/m³), while higher TSM concentrations were well correlated to Rrs,681/Rrs,560. An empirical piecewise algorithm is thus proposed with the switch between the ratios being triggered by Rrs,681/R rs,560 at a threshold value of 0.6. The second algorithm made use of support vector machines (SVMs) as a nonlinear transfer function between TSM concentrations and remote-sensing reflectance ratios Rrs,681/R rs,560, Rrs,665/Rrs,560, and Rrs,560/Rrs,490. Results show that both algorithms perform better (31% and 25%, respectively) than other published TSM algorithms including the MERIS Case 2 water processor (C2R) neural network algorithm in the study area. (Au)

F, D, E, J, H
Carbon; Climate change; Colored dissolved organic matter; Environmental impacts; Estuarine ecology; Measurement; Oceanography; Optical properties; Phytoplankton; Primary production (Biology); Remote sensing; Runoff; Satellites; Sediment transport; Suspended solids; Winds

G07, G03, G0812
Arctic Ocean; Canadian Beaufort Sea; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.; Yukon River, Alaska/Yukon


Dynamique microbienne dans un écosystème côtier arctique : la transition hiver-printemps   /   Terrado, R.   Vincent, W.F. [Supervisor]   Massana, R. [Supervisor]
Québec, Québec : Université Laval, 2006.
x, 90 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR21727)
ISBN 978-0-494-21727-6
References.
Thesis (M.Sc.) - Université Laval, Québec, Québec, 2006.
Front material, Introduction, and Conclusion générale in French; Chapters 1 and 2 in English.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 74787.
Languages: English or French
Web: http://www.collectionscanada.gc.ca/obj/thesescanada/vol2/002/MR21727.PDF
Libraries: OONL

Light and nutrients are the two driving forces in the growth and development of algal blooms in oceanic waters. In the Arctic, seasonal ice cover strongly influences the availability of both resources to phytoplankton communities. The maintenance of a strong halocline over winter prevents entrainment of deep nutrients into the photic zone, which means that high concentrations of nutrients are not available in early spring with the return of daylight following the continuous arctic night. The primary aim of the present study was to describe the standing stocks and dynamics of microbial communities during the winter-spring transition in a coastal region in the Arctic, Franklin Bay in the Beaufort Sea region of the Canadian Western Arctic. We added an experimental component to evaluate the influence of nutrient availability on the development of the protist community in the early spring phase of the dark-light transition in this arctic shelf ecosystem. Within the mixed layer of Franklin Bay the heterotrophic biomass did not change substantially between winter and spring. Prokaryotic concentrations varied little with depth in the water column, with cell numbers ranging from 7.29×10**7 to 3.19×10**8 cells/l. Heterotrophic protists were dominated by small cells in both winter and spring. In terms of biomass protists with a diameter >10 µm generally dominated standing stocks; heterotrophic protist biomass integrated for the upper mixed layer ranged from 31 to 262 mg C/m². Phytoplankton was present during winter and increased during spring as irradiance levels increased. The most common were Micromonas-like cells <2 µm with concentrations between 1.8×10**4 and 6.23×10**5 cells/l. Protist community biomass during winter was mostly dominated by heterotrophic organisms while in spring there was a shift in the community composition, with an increase in the phototrophic biomass and a change in the dominant species. The experimental results indicated that this transition from a heterotrophic dominated winter community to an autotrophic dominated spring community was not influenced by nutrient conditions. The results imply that light rather than nutrients, was the principal driving force for microbial dynamics during the spring-winter transition. (Au)

I, H, G, D, J
Algae; Animal growth; Animal population; Bacteria; Biological sampling; Biomass; Carbon; Chlorophyll; Diatoms; Fluorometry; Food chain; Genetics; Ice cover; Light; Marine ecology; Microbial ecology; Microorganisms; Nitrogen; Ocean temperature; Phosphorus; Photosynthesis; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Protozoa; Salinity; Sea ice; Seasonal variations; Silica; Size; Solar radiation; Spatial distribution; Theses; Water masses

G0815
Franklin Bay, N.W.T.


Microbial food web responses to light and nutrients beneath the coastal Arctic Ocean sea ice during the winter-spring transition   /   Terrado, R.   Lovejoy, C.   Massana, R.   Vincent, W.F.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 964-977, ill.)
References.
ASTIS record 65261.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.11.001
Libraries: ACU

We measured the abundance and biomass of phototrophic and heterotrophic microbes in the upper mixed layer of the water column in ice-covered Franklin Bay, Beaufort Sea, Canada, from December 2003 to May 2004, and evaluated the influence of light and nutrients on these communities by way of a shipboard enrichment experiment. Bacterial cell concentrations showed no consistent trends throughout the sampling period, averaging (±SD) 2.4 (0.9)×10**8 cells/L; integrated bacterial biomass for the upper mixed layer ranged from 1.33 mg C/m³ to 3.60 mg C/m³. Small cells numerically dominated the heterotrophic protist community in both winter and spring, but in terms of biomass, protists with a diameter >10 µm generally dominated the standing stocks. Heterotrophic protist biomass integrated over the upper mixed layer ranged from 1.23 mg C/m³ to 6.56 mg C/m³. Phytoplankton biomass was low and variable, but persisted during the winter period. The standing stock of pigment-containing protists ranged from a minimum value of 0.38 mg C/m³ in winter to a maximal value of 6.09 mg C/m³ in spring and the most abundant taxa were Micromonas-like cells. These picoprasinophytes began to increase under the ice in February and their population size was positively correlated with surface irradiance. Despite the continuing presence of sea ice, phytoplankton biomass rose by more than an order of magnitude in the upper mixed layer by May. The shipboard experiment in April showed that this phototrophic increase in the community was not responsive to pulsed nutrient enrichment, with all treatments showing a strong growth response to improved irradiance conditions. Molecular (DGGE) and microscopic analyses indicated that most components of the eukaryotic community responded positively to the light treatment. These results show the persistence of a phototrophic inoculum throughout winter darkness, and the strong seasonal response by arctic microbial food webs to sub-ice irradiance in early spring. (Au)

I, H, G, D, J
Animal growth; Animal population; Bacteria; Biomass; Carbon; Chlorophyll; Diatoms; Fluorometry; Food chain; Genetics; Ice cover; Light; Marine ecology; Microbial ecology; Microorganisms; Nitrogen; Phosphorus; Photosynthesis; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Sea ice; Seasonal variations; Silica; Size

G0815
Franklin Bay, N.W.T.


Microbial genetic diversity in Arctic seas   /   Terrado, R.   Pedneault, E.   Thaller, M.   Scarcella, K.   Potvin, M.   Lovejoy, C.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 309
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67360.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Microbes are a heterogeneous group that includes bacteria, archaea and small single celled protists, and are key to understanding the dynamics of marine ecosystems. They are numerically the most abundant organisms in arctic seas and despite their small size they account for the bulk of biomass. Marine microbes are responsible for much of global carbon and nitrogen cycling and are important players in other nutrient cycles. The study of different genes, their function, diversity, and expression leads to a better understanding of the detailed role of microbes in our ecosystems. Here we present some insights on the microbial diversity in arctic seas. Marine archaea make up a significant proportion of the prokaryotes in arctic marine systems. Recent studies suggest that members of this major clade could be responsible for much of the nitrification in the ocean. A key gene in the nitrification metabolic pathway is the ammonium monooxygenase subunit A (amoA) gene. Results show the presence of this gene in Arctic waters. Another gene of interest related to nitrogen metabolism is assimilatory nitrate reductase (NR), present in phytoplankton cells. This enzyme is responsible for the reduction of nitrate to nitrite and is essential for the utilization of nitrate by photosynthetic plankton. Results show unexpected diversity of this gene throughout Canada's three oceans (Arctic, Atlantic and Pacific). The diversity of protists has also been studied using the 18s rRNA gene. We have found a diverse community of protists with geographic and seasonal distribution patterns, the recurrence of these organisms is evident with many of the sequences retrieved from organisms reappearing under similar conditions in different years. Furthermore, composition of this protist community varies seasonally, for example the mesopelagic microbial community was dynamically coupled to the upper mixed layer and to the deep offshore ocean. An especially abundant group of sequences retrieved from the Arctic were related to microparasites, and the diversity of one of such groups, Amoebophryra, reflects different infection types. Overall, arctic seas present a distinct and diverse microbial community that harbours a pool of microbial genes implicated in nutrient cycles and food webs. Our work tracking these microbes and their genes and interactions within microbial communities will provide essential information for modellers and others who wish to predict the consequences of changing circulation and ice cover in the arctic. (Au)

H, I, D, J
Archaea; Bacteria; Carbon cycling; Chemical oceanography; Enzymes; Food chain; Genetics; Marine ecology; Microbial ecology; Microorganisms; Nitrogen; Nitrogen cycling; Oceanography; Photosynthesis; Phytoplankton; Seasonal variations; Spatial distribution

G081
Canadian Arctic waters


Mesopelagic protists : diversity and succession in a coastal Arctic ecosystem   /   Terrado, R.   Vincent, W.F.   Lovejoy, C.
(Aquatic microbial ecology, v. 56, no. 1, July 2009, p. 25-40, ill.)
References.
Indexed a PDF file from the Web.
This work was conducted within the Canadian Arctic Shelf Exchange Study (CASES).
ASTIS record 71787.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/249.pdf
Web: doi:10.3354/ame01327

We investigated marine protist diversity from below the euphotic zone during 4 consecutive seasons (November 2003 to July 2004) from a fixed station in the Canadian Arctic (Franklin Bay, Beaufort Sea). DGGE analysis and 18S rRNA gene clone libraries showed that this mesopelagic protist community was dynamic, with marked changes in taxonomic and functional community composition in different seasons. The most frequently recovered sequences in autumn were related to heterotrophic dinoflagellates. In late December 2003, an abrupt change in the community composition occurred following an influx of water from the lower Pacific halocline that flowed onto the Arctic continental shelf and into Franklin Bay. Subsequently, the most frequently retrieved sequences matched uncultured marine alveolates, which are thought to be primarily parasites. This community changed little over the winter, with modest changes in spring marked by the addition of taxa. Summer libraries from 2004 were once more dominated by dinoflagellate sequences with a community very similar to that at the end of autumn 2003. These summer and autumn communities corresponded to periods of higher phytoplankton sedimentation rates in the euphotic zone. We suggest that the deep protist community may reform annually in response to primary production higher in the water column and that the winter mesopelagic protist community is dynamically coupled to the deep offshore ocean. (Au)

H, I, D, J
Bathymetry; Benthos; Biological sampling; Carbon cycling; Dinoflagellata; Fluorometry; Genetics; Heterotrophic bacteria; Light; Marine ecology; Microbial ecology; Microscopes; Ocean currents; Ocean floors; Ocean temperature; Parasites; Photosynthesis; Phytoplankton; Primary production (Biology); Salinity; Seasonal variations; Sedimentation; Solar radiation; Spectroscopy; Water masses

G0815, G03
Amundsen Gulf, N.W.T.; Arctic Ocean; Franklin Bay, N.W.T.


Diversité et succession des protistes dans l'océan Arctique   /   Terrado, R.   Lovejoy, C. [Supervisor]   Vincent, W.F. [Supervisor]
Québec, Québec : Université Laval, 2011.
xix, 181 p. : ill., maps ; 28 cm.
Appendix.
References.
Thesis (Ph.D.) - Université Laval, Québec, Québec, 2011.
Front material, Chapter 1 (Introduction générale), and Chapter 5 (Conclusion générale) in French; Chapters 2, 3, and 4 in English.
Indexed a PDF file available from Université Laval.
ASTIS record 74983.
Languages: English or French
Web: http://www.theses.ulaval.ca/2011/27849/27849.pdf
Libraries: OONL

The Arctic is the region in Earth where climate change is most pronounced. The study of the diversity of microorganisms, their community dynamics and environmental factors acting on them are therefore important to understand how these communities will react to environmental changes. The subject of this thesis is to investigate the diversity of protists and their community dynamics in the Arctic Ocean, from a spatial and temporal point of view. The methodology used through this study is based on the analysis of 18S rDNA sequences. The seasonal study of the protists community in the mesopelagic zone showed a dynamic assemblage with a distinct composition in winter-spring and summer-autumn. The dynamic of this community was associated to hydrographical changes and to a coupling with the euphotic zone. This coupling was reflected by a greater proportion of sequences associated with heterotrophic dinoflagellates during summer-fall. In the euphotic zone, the spring transition presented an increase in autotrophic biomass. However, when chlorophyll a reached its highest level, the activity of heterotrophic dinoflagellates and ciliates was stimulated. The study of the protist diversity at the end of the production season in the euphotic zone showed that water masses with a common origin presented more similar protist assemblages. Nevertheless, a group of taxons was found to be widely distributed in Arctic waters. Among these there are autotrophic, heterotrophic and parasitic taxa. This thesis has increased the knowledge of the dynamics of autotrophic organisms in the pelagic arctic environments and offers a new vision of the ecology of heterotrophic and parasitic protists. Results stress the need to consider these heterotrophic protists when studying the response of the biogeochemical cycles to climate change in the Arctic. (Au)

I, H, G, D, J, E
Algae; Animal distribution; Animal population; Animal taxonomy; Bacteria; Bathymetry; Benthos; Biological productivity; Biological sampling; Biomass; Carbon cycling; Chlorophyll; Ciliata; Climate change; Diatoms; Dinoflagellata; Fluorometry; Food chain; Genetics; Ice leads; Light; Marine ecology; Microbial ecology; Microorganisms; Ocean currents; Ocean floors; Ocean temperature; Oceanography; Parasites; Photosynthesis; Phytoplankton; Plant distribution; Plant growth; Plant taxonomy; Polynyas; Primary production (Biology); Protozoa; Salinity; Sea ice; Seasonal variations; Sedimentation; Solar radiation; Spatial distribution; Theses; Water masses

G0815, G03, G09, G12, G141
Amundsen Gulf, N.W.T.; Barents Sea; Canada Basin, Arctic Ocean; Franklin Bay, N.W.T.; Greenland Sea; North Water Polynya, Baffin Bay; Norwegian Sea; Svalbard waters


Modélisation individu-centrée de la croissance et de la survie larvaire de la morue arctique (Boreogadus saida) dans deux polynies   /   Thanassekos, S.   Fortier, L. [Supervisor]
Québec, Québec : Université Laval, 2011.
xiv, 118 p. : ill., maps ; 28 cm.
Thesis (Ph.D.) - Laval Université, Québec, Québec, 2011.
Indexed a PDF file from the Web.
References.
Contents: Chapitre 1: Introduction générale - Chapitre 2 : An Individual Based Model of Arctic cod (Boreogadus saida) early life in Arctic polynyas: I. Simulated growth in relation to hatch date in the Northeast Water (Greenland Sea) and the North Water (Baffin Bay) - Chapitre 3 : An Individual Based Model of Arctic cod (Boreogadus saida) early life in Arctic polynyas: II. Length-dependent and growth-dependent mortality - Chapitre 4 : A spatially explicit individual-based model of Arctic cod (Boreogadus saida) early life: transports and spatial sub-sampling in the North Water (Baffin Bay).
ASTIS record 74815.
Languages: English or French
Web: http://www.theses.ulaval.ca/2011/27997/27997.pdf
Libraries: QQLAS

Within the Arctic food web, Arctic cod (Boreogadus saida) is the dominant trophic link between zooplankton and higher predators such as seals and sea-birds. An ice-dependent lifestyle and a specialized physiology make this species particularly vulnerable to the predicted reduction in ice-cover and the potential invasion of its ecological niche by boreal generalists. With the unfolding of climate warming which is particularly intense in the Arctic, it is essential to document the factors that control the fate of this key species. The primary focus of this thesis is the identification of the necessary and sufficient processes required in a mathematical model to realistically simulate the growth and survival of the larval stage of Arctic cod. An individual-based model was developed and validated with observations collected in the North Water (Baffin Bay) and the Northeast Water (Greenland Sea). Temperature, as well as the concentration and quality of prey were necessary to reproduce observed growth and its regional differences. Predation pressure was simulated using a length- and growth-dependent mortality which allowed the selective elimination of small and slow-growing individuals. The model took into account the hatch-date of individuals to reproduce differences in life trajectory among individuals hatched before and after the polynya opened. For instance, early hatchers grew slower than late hatchers due to lower temperatures, but this trend was reversed if the yolk exhaustion of early hatchers coincided with high prey concentrations. A novel method of model output sub-sampling accounting for the age, hatch-date and geographical position of individuals captured at sea, reproduced the inevitable discontinuities that plague field observations. This method improved model validation, allowed weaknesses to be identified and highlighted new research directions. The model output sub-sampling has wide-ranging applications in individual-based modeling and is applicable toany model attempting to simulate organisms that can be aged. (Au)

I, D, G, J
Animal distribution; Animal food; Animal growth; Animal live-capture; Animal mortality; Animal population; Arctic cod; Biological sampling; Energy budgets; Fish larvae; Fish spawning; Food chain; Forecasting; Ice cover; Marine ecology; Mathematical models; Numeric databases; Ocean temperature; Oceanography; Polynyas; Predation; Sea ice; Sea ice ecology; Seasonal variations; Theses; Trophic levels

G09, G0815, G12
Canadian Arctic Islands waters; North Water Polynya, Baffin Bay; Northeast Water Polynya, Greenland Sea; Qaanaaq waters, Greenland


Long-range predictions of the shipping season in Hudson Bay : a statistical approach   /   Tivy, A.   Alt, B.   Howell, S.   Wilson, K.   Yackel, J.
(Weather and forecasting, v. 22, no. 5, Oct. 2007, p.1063-1075, ill., maps)
References.
ASTIS record 74300.
Languages: English
Web: doi:10.1175/WAF1038.1
Libraries: ACU

Despite recent reductions in Arctic sea ice extent and the associated increase in both the recreational and commercial use of ice-infested waters, long-range prediction of operationally relevant sea ice parameters is an area of seasonal forecasting that has received little attention. Statistical methods that isolate and exploit empirical relationships between antecedent low-frequency climate variability and specific variables of interest are often used to solve seasonal forecasting problems. In this study, simple multiple linear regression (MLR) techniques are used to improve the skill of the seasonal (3-month lead) forecast of the breakup and clearing of sea ice along the shipping route through Hudson Bay that is issued each March by the Canadian Ice Service of Environment Canada. Using sea ice and climate data from 1972 to 2002, predictive MLR models are developed for the spring opening date of the shipping route and the latest expected opening date. A success rate of 77% over the 1972-2002 period for the opening date, from an MLR model that explains 76% of the variability in the original time series with a mean absolute error (MAE) of 0.38, is a marked improvement over the 48% success rate of the current analog methodology. The success rate of the model for the latest expected date is 87%; the modeled time series adequately represented interannual variability in the observed time series (r = 0.71) with a low MAE (MAE = 0.51). Results from a series of model diagnostics that include Monte Carlo simulations, cross validation, and analysis of residuals, suggest the final models are statistically valid and are not influenced by artificial skill. The main source of predictive skill in the model is winter low-frequency variability in North Atlantic sea surface temperatures and 500-mb geopotential heights; physical processes that may explain this link are presented. It is concluded that simple multiple linear regression techniques can be applied to generate use-specific seasonal forecasts of sea ice conditions and that the empirical knowledge gained in the model development may help elucidate or identify physical processes in the climate system. (Au)

G, D, E, L
Atmospheric temperature; Breakup; Canadian Ice Service; Climate change; Climatology; Databases; Effects of climate on ice; Forecasting; Ice cover; Marine transportation; Mathematical models; Melting; Ocean temperature; Sea ice; Seasonal variations; Spatial distribution; Surface temperature; Temporal variations

G0814, G0815, G11
Canadian Arctic waters; Hudson Bay; Hudson Strait, Nunavut/Québec; North Atlantic Ocean


Sea ice in the Canadian Arctic : inter-annual variability and predictability   /   Tivy, A.   Yackel, J. [Supervisor]
Calgary, Alta. : University of Calgary, 2009.
xix, 202 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. NR54450)
ISBN 978-0-494-54450-1
Thesis (Ph.D.) - University of Calgary, Calgary, Alta., 2009.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
References.
ASTIS record 74747.
Languages: English
Libraries: ACU

This dissertation investigates the utility of statistical methods towards the development of predictive sea ice models in support of seasonal forecasting efforts at the North American Ice Service (NAIS), the government agency responsible for relaying ice information to the public. Seasonal sea ice forecasting models are required to (a) predict the dates of actual sea ice events and (b) predict the general pattern of break-up. Statistical methods are employed because deterministic models do not yet adequately represent seasonal or inter-annual variability in sea ice to the level of accuracy required for forecasting. The Canadian Ice Service Digital Archive (CISDA) dataset of weekly ice charts is used as the foundation dataset. The issue of changing sensors over time in CISDA is addressed allowing the full dataset, which begins almost 20 years before the satellite era, to be used in model development. Model development is focused on the Hudson Bay region of Canada where the greatest reduction in summer sea ice cover is observed. Two forecasting models are developed. The first is an exploratory method based on multiple linear regression. Tested on forecasting the opening date of the shipping route to Churchill (OWRC), the model explains 76% of the variability in the OWRC time-series with a forecast success rate of 77%. The methodology has been automated and the regression based seasonal forecasting model (CIS-RSF) will be used operationally at NAIS for the first time in 2009. An initial evaluation of CIS-RSF on 21 time-series of sea ice events in the Arctic produced 7 forecast models; the skill of each model is greater than persistence and the current NAIS forecast technique. The second model uses Canonical Correlation Analysis (CCA). To date, it is the only sea ice forecasting model capable of predicting the spatial distribution of sea ice. The model is used to predict the spatial pattern of July ice using North Atlantic SST anomalies in the preceding fall(6 to 9 month lead) as the main predictor. The model explains 53% of the inter-annual variability in ice concentration and has high skill along the shipping route to Churchill. CCA diagnostics suggest a link between the first CCA mode and the Atlantic Multi-decadal Oscillation which may help explain the recent dramatic decrease in ice cover in this region. (Au)

G, D, E
Archives; Atmospheric temperature; Breakup; Canadian Ice Service; Climate change; Databases; Effects of climate on ice; Formation; Ice cover; Ice forecasting; Maps; Mathematical models; Melting; Ocean temperature; Ocean-atmosphere interaction; Sea ice; Seasonal variations; Surface properties; Temporal variations; Thermodynamics; Theses; Thickness; Weather stations; Winds

G0814, G11, G0815, G081
Canadian Arctic waters; Canadian Beaufort Sea; Hudson Bay; Hudson Strait region, Nunavut/Québec; North Atlantic Ocean


Vertical stability and the annual dynamics of nutrients and chlorophyll fluorescence in the coastal, southeast Beaufort Sea   /   Tremblay, J.-É.   Simpson, K.   Martin, J.   Miller, L.   Gratton, Y.   Barber, D.   Price, N.M.
(Annual cycles on the Arctic Ocean shelf : the Canadian Arctic Shelf Exchange Study. Journal of geophysical research, v.113, no. C7, C07S90, July 2008, 14 p., ill.)
References.
ASTIS record 65020.
Languages: English
Web: doi:10.1029/2007JC004547
Libraries: ACU

The first quasi-annual time series of nutrients and chlorophyll fluorescence in the southeast Beaufort Sea showed that mixing, whether driven by wind, local convection, or brine rejection, and the ensuing replenishment of nutrients at the surface were minimal during autumn and winter. Anomalously high inventories of nutrients were observed briefly in late December, coinciding with the passage of an eddy generated offshore. The concentrations of (NO3)- in the upper mixed layer were otherwise low and increased slowly from January to April. The coincident decline of (NO2)- suggested nitrification near the surface. The vernal drawdown of (NO3)- in 2004 began at the ice-water interface during May, leaving as little as 0.9 µM of (NO3)- when the ice broke up. A subsurface chlorophyll maximum (SCM) developed promptly and deepened with the nitracline until early August. The diatom-dominated SCM possibly mediated half of the seasonal (NO3)- consumption while generating the primary (NO2)- maximum. Dissolved inorganic carbon and soluble reactive phosphorus above the SCM continued to decline after (NO3)- was depleted, indicating that net community production (NCP) exceeded (NO3)- -based new production. These dynamics contrast with those of productive Arctic waters where nutrient replenishment in the upper euphotic zone is extensive and NCP is fueled primarily by allochthonous (NO3)-. The projected increase in the supply of heat and freshwater to the Arctic should bolster vertical stability, further reduce (NO3)- -based new production, and increase the relative contribution of the SCM. This trend might be reversed locally or regionally by the physical forcing events that episodically deliver nutrients to the upper euphotic zone. (Au)

J, H, D, G, A, E
Algae; Bacteria; Biological productivity; Biological sampling; Biomass; Breakup; Carbon cycling; Chemical oceanography; Chlorophyll; Climate change; Continental shelves; Density; Diatoms; Fast ice; Fluorometry; Marine ecology; Measurement; Microbial ecology; Microorganisms; Nitrogen; Nitrogen cycling; Ocean currents; Ocean temperature; Photosynthesis; Phytoplankton; Plant growth; Plant nutrition; Primary production (Biology); River discharges; Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Spectroscopy; Temporal variations; Thickness; Water masses; Winds; Winter ecology

G07, G09
Amundsen Gulf, N.W.T.; Baffin Bay-Davis Strait; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Nutrient dynamics in the southeast Beaufort Sea during the CFL, CASES and ArcticNet campaigns : implications for primary productivity   /   Tremblay, J.-É.   Martin, J.   Gagnon, J.   Pineault, S.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 159
Abstract of a Topical Session presentation.
Indexed a PDF file from the Web.
ASTIS record 67028.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

Nutrients play a major role in Arctic marine ecosystems by setting an upper bound to the yield of primary producers and renewable living resources. The evidence is mounting that net productivity and the associated fluxes of biogenic carbon respond to the modulation of nitrogen supply by climate, through its effects on the freshwater balance, sea ice and atmosphere-ocean coupling. With the successful completion of the CFL sampling program in 2008, we now have comprehensive information on nutrient renewal from autumn to winter in the Gulf of Amundsen. This data set builds on the previous CASES overwintering, which provided similar information for the adjacent Franklin Bay (2004), and three ArcticNet expeditions (2005, 2006, 2007) that complete our time series of autumn data. While some of these years are generally similar despite contrasted ice regimes, striking anomalies occurred in relation to local physical forcing and the passage of physical singularities generated remotely. In this presentation, we put these events into perspective through a comparison with the "average" setting, assess possible links with weather patterns and discuss their implications for primary production on a local and remote basis. (Au)

H, D, E, G
Carbon; Ice cover; Meteorology; Nitrogen; Ocean-atmosphere interaction; Phytoplankton; Plant nutrition; Primary production (Biology); Sea ice; Spatial distribution

G0815, G07
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea


Climate-driven changes in the biological productivity of the Arctic Ocean   /   Tremblay, J.-É.
In: CMOS Congress 2009 : sea and sky come to life, Halifax, Nova Scotia, 31 May-4 June = Congrés SCMO 2009 : mer et ciel s'animent, Halifax, Nouvelle-Écosse, 31 mai-4 juin. - Ottawa : CMOS, 2009, [2] p.
Abstract of an oral presentation in Session 4B-302.1, ID:3003.
Session 4B-302: Climate Variability and Marine Ecosystems (Part 1).
Indexed a PDF file available online.
ASTIS record 75369.
Languages: English
Web: http://www.cmos.ca/CongressAbstracts/cong4309.pdf

Assessing the current and future productivity of the marine ecosystem is a major challenge for Arctic oceanographers. Remote sensing is useful to monitor large-scale patterns in the productivity of the upper euphotic zone, but is ill-equipped to monitor key events that occur in and underneath seasonal sea ice or at the base of the euphotic zone during the ice-free period. Our ability to detect trends and measure change is also hampered by the lack of in situ time series that include quantitative indicators of the timing, functional composition and yield of primary production in addition to routine physical parameters. This presentation offers a reflection based on historical data and recent process-oriented research and monitoring initiatives in the western Arctic. Ten years ago, a synthesis of data published since the 1950's suggested a positive, spatial correlation between pelagic primary production and the duration of the ice-free period, which might be caused by systemic differences in the availability of photosynthetically-active radiation (PAR) and/or nutrients. A new, stringent re-analysis of this literature highlights how the most productive systems are currently located in peripheral Arctic seas or polynyas that are susceptible to nutrient supply by lateral advection, convection and wind-driven mixing or upwelling. Less productive sectors of the Canada Basin will not acquire this susceptibility simply because multi-year ice vanishes or the lifetime of seasonal ice declines. The results obtained during the programs NOW, CASES, ArcticNet and IPY-CFL indicate that large variations in nitrate-based new production are not primarily explained by differences in cumulative exposure to PAR. A hierarchy is proposed, whereby order-of-magnitude differences in primary productivity at the pan-arctic scale are controlled by the nature of episodic nutrient subsidies and smaller, 2-3 fold increases within a given region are due to synergistic interactions between PAR, periodic nutrient inputs and biological processes at the base of the euphotic zone where deep chlorophyll maxima persist. (Au)

H, D, G, E, J
Chlorophyll; Climate change; Environmental impacts; Ice cover; Marine ecology; Nitrogen oxides; Ocean currents; Oceanography; Photosynthesis; Plankton; Plant nutrition; Polynyas; Primary production (Biology); Sea ice; Solar radiation; Spatial distribution; Water masses; Winds

G03, G081
Arctic Ocean; Canada Basin, Arctic Ocean; Canadian Arctic waters


What have we learned from ten years of nutrient investigations in the western Arctic?   /   Tremblay, J.E.   Gratton, Y.
In: ASLO Aquatic Sciences Meeting 2009 : a cruise through Nice waters : meeting abstracts : Nice, France, 25-30 January 2009. - [Waco, Texas] : ASLO, 2009, p. 267
Abstract of an oral presentation.
Indexed a PDF file available online.
ASTIS record 75355.
Languages: English
Web: http://aslo.org/nice2009/files/2009asm-abstracts.pdf

What have we learned from ten years of nutrient investigations in the western Arctic? Primary producers at the base of the food web rely on two resources that are highly seasonal in the upper Arctic Ocean: nutrients and light. Their relative importance in controlling short-term and annual rates of primary production in seasonally ice-free regions is not well understood and needs to be addressed in the present context of rapid climate change. Here we discuss how nutrient loading can be affected by changes in (1) the freshwater balance (2) horizontal circulation and (3) the "rules of engagement" between the atmosphere and the water column. Examples are drawn from the large nutrient database obtained during the International North Water Polynya Program, two overwintering expeditions in the Southeast Beaufort Sea (Canadian Arctic Shelf Exchange Study and the IPY/Circumpolar Flaw Lead System Study) and annual ArcticNet surveys. Data gathered during summer and autumn are compared with winter baselines to assess the relative importance of initial conditions at the onset of the growth season, subsequent nutrient renewal and a protracted ice-free season on cumulative new production. This analysis highlights the relatively unproductive character of the Beaufort Sea under "average" conditions, but shows how local forcing events and the passage of remotely-generated oceanic singularities during autumn or winter set the stage for productive episodes. (Au)

H, D, E, J
Climate change; Databases; Environmental impacts; Food chain; Light; Marine ecology; Ocean currents; Ocean-atmosphere interaction; Plant growth; Plant nutrition; Primary production (Biology); Seasonal variations; Water masses

G09, G07, G0815
Amundsen Gulf, N.W.T.; Canadian Arctic Islands waters; Canadian Beaufort Sea; North Water Polynya, Baffin Bay


What have we learned from ten years of nutrient investigations in the western Arctic?   /   Tremblay, J.E.   Gratton, Y.
In: 2009 abstracts : Arctic Frontiers, Tromsø : Arctic marine ecosystems in an era of rapid climate change, Arctic Ocean governance, 18-23 January. - Tromsø, Norway : Arctic Frontiers Secretariat, 2009, p. 46
Abstract of an oral presentation.
Indexed a PDF file available online.
ASTIS record 75368.
Languages: English
Web: http://www.arcticfrontiers.com/index.php?option=com_docman&task=doc_download&gid=88&Itemid=306&lang=en

Primary producers at the base of the food web rely on two resources that are highly seasonal in the upper Arctic Ocean: nutrients and light. Their relative importance in controlling short-term and annual rates of primary production in seasonally ice-free regions is not well understood and needs to be addressed in the present context of dramatic climate change. Here we discuss how nutrient loading can be affected by changes in (1) the freshwater balance (2) horizontal circulation and (3) the "rules of engagement" between the atmosphere and the water column. Examples are drawn from the large nutrient database obtained during the International North Water Polynya Program, two overwintering expeditions in the Southeast Beaufort Sea (Canadian Arctic Shelf Exchange Study and the IPY/Circumpolar Flaw Lead System Study) and annual ArcticNet surveys. Data gathered during summer and autumn are compared with winter baselines to assess the relative importance of initial conditions at the onset of the growth season, subsequent nutrient renewal and a protracted ice-free season on cumulative new production. This analysis highlights the relatively unproductive character of the Beaufort Sea under "average" conditions, but shows how local forcing events and the passage of remotely generated oceanic singularities during autumn or winter can set the stage for productive episodes. (Au)

D, H, E, J
Climate change; Databases; Environmental impacts; Food chain; Light; Marine ecology; Ocean currents; Ocean-atmosphere interaction; Plant growth; Plant nutrition; Primary production (Biology); Seasonal variations; Water masses

G09, G07, G0815
Amundsen Gulf, N.W.T.; Canadian Arctic waters; Canadian Beaufort Sea; North Water Polynya, Baffin Bay


Production bactérienne et structure du réseau alimentaire microbien dans le fleuve Mackenzie et l'océan Arctique côtier   /   Vallières, C.   Vincent, W.F. [Supervisor]   Laurion, I. [Supervisor]
Québec, Québec : Université Laval, 2007.
xiii, 125, [13] p. : ill., maps ; 28 cm.
Appendices.
References.
Thesis (M.Sc.) - Université Laval, Québec, Québec, 2007.
Front material, Introduction générale, and Conclusions générale in French; Chapters 1 and 2 in English.
Indexed a PDF file available from Université Laval.
ASTIS record 74979.
Languages: English or French
Web: http://www.theses.ulaval.ca/2007/24315/24315.pdf

Globally significant quantities of organic carbon are stored in northern permafrost soils, but little is known about how this carbon is processed by microbial communities once it enters rivers and is transported to the coastal Arctic Ocean. As part of the Arctic River-Delta Experiment (ARDEX), we measured environmental and microbiological variables along a 300 km transect across the Mackenzie River and coastal Beaufort Sea in July-August 2004 to investigate the river and estuarine gradients in microbial community structure and activity, and to evaluate the influence of UV exposure and carbon supply on bacterial processes in these ecosystems. Microbial community structure changed along the transect and the contribution of particle-attached bacteria was significantly higher in riverine and transition zone stations. Experimental results showed that bacterial metabolism was carbon limited in the Mackenzie River. Photodegradation increased organic carbon biolability in the Mackenzie River and decreased it in the Beaufort Sea. (Au)

H, I, J, F, D, E
Animal distribution; Animal growth; Animal respiration; Bacteria; Biodegradation; Biological productivity; Biological sampling; Carbon; Carbon cycling; Carbon dioxide; Chlorophyll; Climate change; Cyanophyceae; Diatoms; Dinoflagellata; Environmental impacts; Estuarine ecology; Fluorometry; Food chain; Fresh-water ecology; Marine ecology; Metabolism; Microbial ecology; Microorganisms; Nitrogen; Ocean temperature; Phosphorus; Phytoplankton; Plankton; Plant distribution; Plant respiration; Protozoa; Rivers; Salinity; Sea water; Solar radiation; Suspended solids; Temperature; Theses; Water masses

G07, G0812, G0826, G0814
Baleine, Grande rivière de la, Québec; Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Hudson Bay; Kugmallit Bay, N.W.T.; Middle Channel (Mackenzie River), N.W.T.


Bacterial production and microbial food web structure in a large Arctic river and the coastal Arctic Ocean   /   Vallières, C.   Retamal, L.   Ramlal, P.   Osburn, C.L.   Vincent, W.F.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 756-773, ill., maps)
References.
ASTIS record 65246.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/225.pdf
Web: doi:10.1016/j.jmarsys.2007.12.002
Libraries: ACU

Globally significant quantities of organic carbon are stored in northern permafrost soils, but little is known about how this carbon is processed by microbial communities once it enters rivers and is transported to the coastal Arctic Ocean. As part of the Arctic River-Delta Experiment (ARDEX), we measured environmental and microbiological variables along a 300 km transect in the Mackenzie River and coastal Beaufort Sea, in July-August 2004. Surface bacterial concentrations averaged 6.7×10**5 cells/mL with no significant differences between sampling zones. Picocyanobacteria were abundant in the river, and mostly observed as cell colonies. Their concentrations in the surface waters decreased across the salinity gradient, dropping from 51,000 (river) to 30 (sea) cells/mL. There were accompanying shifts in protist community structure, from diatoms, cryptophytes, heterotrophic protists and chrysophytes in the river, to dinoflagellates, prymnesiophytes, chrysophytes, prasinophytes, diatoms and heterotrophic protists in the Beaufort Sea. Size-fractionated bacterial production, as measured by 3H-leucine uptake, varied from 76 to 416 ng C/L/h. The contribution of particle-attached bacteria (>3 µm fraction) to total bacterial production decreased from >90% at the Mackenzie River stations to <20% at an offshore marine site, and the relative importance of this particle-based fraction was inversely correlated with salinity and positively correlated with particulate organic carbon concentrations. Glucose enrichment experiments indicated that bacterial metabolism was carbon limited in the Mackenzie River but not in the coastal ocean. Prior exposure of water samples to full sunlight increased the biolability of dissolved organic carbon (DOC) in the Mackenzie River but decreased it in the Beaufort Sea. Estimated depth-integrated bacterial respiration rates in the Mackenzie River were higher than depth-integrated primary production rates, while at the marine stations bacterial respiration rates were near or below the integrated primary production rates. Consistent with these results, PCO2 measurements showed surface water supersaturation in the river (mean of 146% of air equilibrium values) and subsaturation or near-saturation in the coastal sea. These results show a well-developed microbial food web in the Mackenzie River system that will likely convert tundra carbon to atmospheric CO2 at increasing rates as the arctic climate continues to warm. (Au)

H, I, J, F, D, E
Animal distribution; Animal growth; Animal respiration; Bacteria; Biological productivity; Biological sampling; Carbon; Carbon cycling; Carbon dioxide; Climate change; Cyanophyceae; Diatoms; Dinoflagellata; Dissolved organic carbon; Environmental impacts; Estuarine ecology; Fluorometry; Food chain; Fresh-water ecology; Marine ecology; Metabolism; Microbial ecology; Microorganisms; Ocean temperature; Phytoplankton; Plankton; Plant distribution; Plant respiration; Protozoa; Rivers; Salinity; Sea water; Solar radiation; Suspended solids; Temperature; Water masses

G07, G0812
Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Kugmallit Bay, N.W.T.; Middle Channel (Mackenzie River), N.W.T.


Cruise report for the joint DFO / CASES / ArcticNet science program aboard the CCGS "Sir Wilfrid Laurier", 3-22 September 2004   /   van Hardenberg, B.
[Québec, Québec : Université Laval, 2004].
28 p. : ill., maps ; 28 cm.
Cover title.
Indexed a PDF file from the Web.
Appendix.
ASTIS record 74428.
Languages: English
Web: http://www.cases.quebec-ocean.ulaval.ca/CASES0304_Leg10(Laurier)_cruise_report.pdf

Overview: This cruise to the Mackenzie Shelf / Beaufort Sea area of the Arctic was a joint mission between the Canadian Department of Fisheries and Oceans (DFO) and the Canadian Shelf Exchange Study (CASES) group, involving researchers from the Institute of Ocean Sciences (DFO/IOS) and from the Central & Arctic branch (DFO/C&A), the University of Laval (GIROQ) and the Japanese National Institute of Polar Research (NIPR). Our primary objectives were to recover the remaining instrumented oceanographic moorings that were deployed as part of the CASES project, and to provide an opportunity to complete the sampling of biota in the study area over the remainder of the annual cycle both for the CASES project, since the CCGS "Amundsen" that was equipped for the CASES project could not complete a full annual cycle of observations. Ancillary sampling was undertaken as part of the ongoing data collection by the Central & Arctic Branch of DFO. In addition to this, water column profile data were obtained to calibrate acoustic properties at several stations where wave and ice characterization instruments are to be recovered for DFO/IOS during the next science leg aboard, and a number of bottom temperature sensors were recovered from several unusual features on the Beaufort Shelf in support of work by the Pacific Geosciences Center. As part of the CASES research agreement, a wildlife observer from Holman was brought along, and his observations during the cruise have expanded our understanding of the life cycles [in] this area towards the end of the open water season. ... At each station, the primary objective was to recover the moored oceanographic instruments. When time and weather constraints permitted, the next priority was to complete the biological sampling objectives of the CASES program over a year's seasonal cycle using trawls and vertical net hauls with various mesh sizes. In addition, an observer from Holman (N.T.) gathered data on the presence of wildlife along the ship's track and at the locations of science activities. A CTD instrument was lowered at each mooring site to obtain a profile of water property data near the mooring while it was still in place. This is done to determine possible sensor drift over time for the moored instruments, or to obtain accurate data on the acoustic properties of the water. ... (ASTIS)

D, G, E, J, L, B, H, I, A
Acoustic properties; Animal distribution; ArcticNet Inc.; Biological sampling; Canadian Arctic Shelf Exchange Study; Data buoys; Equipment and supplies; Ice cover; Ice navigation; Instruments; Mooring systems; Ocean floors; Ocean waves; Oceanographic instruments; Sea ice; Sea water; Sir Wilfrid Laurier (Ship); Submarine topography; Suspended solids; Temperature; Winds; Zooplankton

G0815, G07
Amundsen Gulf, N.W.T.; Banks Island waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.


Seasonal changes in planktonic bacterivory rates under the ice-covered coastal Arctic Ocean   /   Vaqué, D.   Guadayol, Ò.   Peters, F.   Felipe, J.   Angel-Ripoll, L.   Terrado, R.   Lovejoy, C.   Pedrós-Alió, C.
(Limnology and oceanography, v. 53, no. 6, Nov. 2008, p.2427-2438, ill.)
References.
ASTIS record 65390.
Languages: English
Libraries: ACU

Bacterivory was determined in surface waters of Franklin Bay, western Arctic, over a seasonal ice-covered period (winter-spring, 2003-2004). The objectives were to obtain information on the functioning of the microbial food web under the ice, during winter (from 21 December 2003 to 21 March 2004) and during spring (from 22 March 2004 to 29 May 2004), and to test whether bacterial losses would increase after the increase in bacterial production following the spring phytoplankton bloom. Chl a concentrations ranged from 0.04 to 0.36 µg/L, increasing in March and reaching a peak in April. Bacterial biomass showed no consistent trend for the whole period, and protist biomass followed a pattern similar to that of Chl a. Bacterial production increased 1 week after Chl a concentrations started to increase, while bacterivory rates increased very slightly. Average bacterivory rates in winter (0.16 ±0.07 µg C/L/d) were not significantly different from those in spring (0.29 ±0.24 µg C/L/d). Average bacterial production, on the other hand, was similar to bacterivory rates in winter (0.19 ±0.38 µg C/L/d), but higher than bacterivory in spring (0.93 ±0.28 µg C/L/d). Therefore, bacterial production was controlled by grazers during winter and by substrate concentration in spring. (Au)

H, I, J, D, G
Bacteria; Biological productivity; Biomass; Carbon; Chlorophyll; Fast ice; Fluorometry; Food chain; Identification; Light; Marine ecology; Microbial ecology; Microorganisms; Nitrogen; Ocean temperature; Phosphorus; Phytoplankton; Plankton; Plant nutrition; Predation; Salinity; Sea water; Seasonal variations; Silica; Size; Thickness

G0815
Franklin Bay, N.W.T.


Number and phylogenetic affiliation of bacteria assimilating dimethylsulfoniopropionate and leucine in the ice-covered coastal Arctic Ocean   /   Vila-Costa, M.   Simó, R.   Alonso-Sáez, L.   Pedrós-Alió, C.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 957-963, ill.)
References.
ASTIS record 65267.
Languages: English
Web: doi:10.1016/j.jmarsys.2007.10.006
Libraries: ACU

The ability of bacteria to assimilate sulfur from dimethylsulfoniopropionate (DMSP) was examined in the western Arctic Ocean by combining microautoradiography and fluorescence in situ hybridization (FISH). Assimilation of leucine was also measured for comparative purposes since leucine is considered a universal substrate for bacteria, which use it for protein synthesis. Samples were collected at 3 m depth, through a hole in the ice, in the CASES (Canadian Arctic Shelf Ecosystem Study) overwintering station in Franklin Bay (eastern Beaufort Sea) in March and May 2004 to compare two contrasting situations: winter and early spring. FISH counts indicated that the bacterial assemblage consisted of alpha- (up to 60% of the EUB positive cells), ß- (up to 10%) and gamma-proteobacteria (around 20%), and Bacteroidetes (up to 60%). The ß-proteobacteria were not active with any of the two substrates tested. The remaining groups were much less efficient at assimilating DMSP-sulfur (5% of the cells) than leucine (20-35%) both in winter and in spring. Only the Roseobacter group of alpha-proteobacteria showed a similar assimilation of both substrates. (Au)

H, D
Amino acids; Bacteria; Biochemistry; Chlorophyll; Chromatography; Fluorometry; Metabolism; Proteins; Sea water; Seasonal variations; Sulphides

G0815
Franklin Bay, N.W.T.


Sea ice and life in a river-influenced Arctic shelf ecosystem [preface to a special issue]   /   Vincent, W.F.   Pedrós-Alió, C.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 739-740)
ASTIS record 65228.
Languages: English
Web: doi:10.1016/j.jmarsys.2008.03.003
Libraries: ACU

This special issue presents results from the Canadian Arctic Shelf Exchange Study (CASES) and the Arctic River Delta Experiment (ARDEX). These research programs were formulated in recognition of the importance of the shelf environment for Arctic Ocean processes, and in response to the mounting evidence that northern coastal regions have begun to experience the impact of human-induced climate change, with more severe effects likely in the future. CASES sampling and observations took place in the coastal Beaufort Sea in the vicinity of the Mackenzie River and shelf, and centered on the overarching hypothesis that the atmospheric, oceanic, and hydrologic forcing of sea-ice variability dictates the nature and magnitude of biogeochemical carbon fluxes on and at the edge of the Mackenzie Shelf. ARDEX was a satellite program to CASES that undertook observations and experiments in the Mackenzie River, and that provided complementary information on riverine nutrients, underwater light, organic carbon and microbial processes that influence the shelf ecosystem. ... This issue begins with a set of papers on the Mackenzie River and its estuarine transition zone. ... The next set of papers examines the complex processes that take place in the coastal shelf area. ... The subsequent three papers report observations and analyses from extensive sampling of the sediments throughout the CASES study area. ... A further set of papers deals with the water column microbes. ... The last two papers consider higher trophic levels: zooplankton and beluga whales. ... (Au)

J, D, F, G, I, H, E
Animal distribution; Animal food; Bacteria; Beluga whales; Benthos; Bioaccumulation; Bottom sediments; Carbon cycling; Climate change; Continental shelves; Environmental impacts; Estuarine ecology; Food chain; Foraminifera; Fresh-water ecology; Marine ecology; Mercury; Microbial ecology; Microorganisms; Oceanography; Phytoplankton; Plant distribution; Polynyas; River discharges; Sea ice ecology; Seasonal variations; Suspended solids; Viruses; Wildlife habitat; Zooplankton

G07, G0815, G0812
Bathurst, Cape, waters, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.


Microbial communities and carbon fluxes   /   Vincent, W.F.   Pedrós-Alió, C.   Suttle, C.   Lovejoy, C.   Deming, J.   Osburn, C.   Lesack, L.   Xie, H.   Babin, M.   Wilmotte, A.
In: On thin ice : a synthesis of the Canadian Arctic Shelf Exchange Study (CASES) / Edited by L. Fortier, D. Barber, and J. Michaud. - Winnipeg, Man. : Aboriginal Issues Press, 2008, ch. 5, p. 85-99, ill., maps
References.
ASTIS record 67480.
Languages: English
Libraries: ACU

... The CASES program has provided a remarkable opportunity to examine the community structure and seasonal dynamics of microbial communities within coastal Arctic Ocean waters .... Through the microbiological component of this program, we were able to study the diversity and activities of many forms of microscopic life, including viruses, Archaea and Bacteria (known collectively as prokaryotes), and Eukarya (single-celled members, also known as protists). The CASES microbiological subprogram began with inaugural "Leg 0" aboard CCGS Pierre Radisson in September-October 2002, which allowed sampling of Franklin Bay and the eastern Beaufort Sea, as well as a transect from the Mackenzie River to the edge of the Arctic pack ice over the continental slope. The microbial research then continued from September 2003 to August 2004 aboard CCGS Amundsen, which was stationed in Franklin Bay from November 2003 to June 2004 for measurements during winter and spring .... The satellite program ARDEX (Arctic River Delta Experiment) was undertaken in July-August 2004, aboard a shallow draft research vessel, CCGS Nahidik, in order to sample a transect from Inuvik, 250 km upstream of the mouth the Mackenzie River, to a coastal marine station 50 km offshore. ARDEX provided observations and experiments that were complementary to CASES; specifically, riverine nutrients, organic carbon, and microbial processes that influence the shelf ecosystem. Given the central role of dissolved organic matter (DOM) in microbial processes within river and coastal ecosystems, both CASES and ARDEX were interested in the optical and biogeochemical properties of DOM, as well as its effects on primary production and its photochemical reactivity. ... CASES and its satellite program ARDEX have provided an unprecedented opportunity to explore the microbiology of the Arctic Ocean and to evaluate a broad suite of environmental processes and variables. These observations revealed a rich diversity of Bacteria, Archaea, protists and viruses. Abundant populations of each of these groups were found throughout the year. Contrary to expectation, winter in the Arctic was not found to be a period of biological quiescence, but instead microbial heterotrophic processes continued throughout the period of winter darkness at rates well above background. Even photosynthetic processes began much earlier in the year than expected, thanks to minute eukaryotic cells that were highly adapted to low water temperatures and to the capture of low irradiance levels beneath the ice during early spring. Obviously, winter ecology within Arctic waters is very different from summer ecology. Such difference, and its implications, can only be studied through projects, such as CASES, in which a suitable research platform is available on site throughout all seasons. As a result of CASES, we have learned that small cells dominate carbon fluxes throughout most of the year, and that much of the carbon-processing is associated with microbial consortia attached to particles. We also identified several aspects of this arctic shelf ecosystem that may be vulnerable to climate change, including the presence of obligate cold-adapted species within the plankton community, the sensitivity of deep chlorophyll abundance to changes in underwater irradiance, and the dependence of the stamukhi lake ecosystem on ice integrity, especially during the period of peak discharge from the Mackenzie River. Several features of the studied region may lead to an increased net production of CO2 in a warmer climate. These include an increased change in the photochemical production of CO2 as a function of reduced sea-ice cover, an increased change in the transport and microbial degradation of terrigenous carbon, a loss of the stamukhi lake as a decantation system for particulate organic carbon during peak discharge, and more severe light limitation on photosynthetic CO2-fixation due to increased runoff of CDOM [coloured dissolved organic matter] and non-algal particulates. ... (Au)

H, I, J, D, F
Algae; Animal distribution; Animal physiology; Archaea; Bacteria; Biodegradation; Biological productivity; Biomass; Carbon; Carbon cycling; Carbon dioxide; Chemical oceanography; Chlorophyll; Colored dissolved organic matter; Cyanophyceae; Diatoms; Genetics; Isotopes; Lakes; Light; Marine ecology; Metabolism; Microbial ecology; Microorganisms; Nitrogen; Ocean temperature; Optical properties; Particulate organic matter; Passive microwave remote sensing; Phosphorus; Photosynthesis; Phytoplankton; Plant distribution; Plant growth; Plant nutrition; Plant physiology; Predation; Primary production (Biology); Proteins; River discharges; Salinity; Satellites; Seasonal variations; Size; Spatial distribution; Suspended solids; Ultraviolet radiation; Viruses; Water masses

G07, G0815, G0812
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River region, N.W.T.; Mackenzie River, N.W.T.


Arctic microbial ecosystems and impacts of extreme warming during the International Polar Year   /   Vincent, W.F.   Whyte, L.G.   Lovejoy, C.   Greer, C.W.   Laurion, I.   Suttle, C.A.   Corbeil, J.   Mueller, D.R.
(MERGE / Edited by H. Kanda, P. Convey, T. Naganuma, W. Vincent, and A. Wilmotte. Polar science, v. 3, no. 3, Nov. 2009, p. 171-180, ill., maps)
(PCSP/PPCP contribution, no. 032-09)
References.
ASTIS record 69272.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/253.pdf
Web: doi:10.1016/j.polar.2009.05.004
Libraries: ACU

As a contribution to the International Polar Year program MERGE (Microbiological and Ecological Responses to Global Environmental change in polar regions), studies were conducted on the terrestrial and aquatic microbial ecosystems of northern Canada (details at: http://www.cen.ulaval.ca/merge/). The habitats included permafrost soils, saline coldwater springs, supraglacial lakes on ice shelves, epishelf lakes in fjords, deep meromictic lakes, and shallow lakes, ponds and streams. Microbiological samples from each habitat were analysed by HPLC pigment assays, light and fluorescence microscopy, and DNA sequencing. The results show a remarkably diverse microflora of viruses, Archaea (including ammonium oxidisers and methanotrophs), Bacteria (including filamentous sulfur-oxidisers in a saline spring and benthic mats of Cyanobacteria in many waterbodies), and protists (including microbial eukaryotes in snowbanks and ciliates in ice-dammed lakes). In summer 2008, we recorded extreme warming at Ward Hunt Island and vicinity, the northern limit of the Canadian high Arctic, with air temperatures up to 20.5 °C. This was accompanied by pronounced changes in microbial habitats: deepening of the permafrost active layer; loss of perennial lake ice and sea ice; loss of ice-dammed freshwater lakes; and 23% loss of total ice shelf area, including complete break-up and loss of the Markham Ice Shelf cryo-ecosystem. These observations underscore the vulnerability of Arctic microbial ecosystems to ongoing climate change. (Au)

E, J, F, C, I, H, G, B
Active layer; Animal distribution; Animal population; Archaea; Atmospheric temperature; Bacteria; Biological sampling; Bottom sediments; Breakup; Climate change; Cyanophyceae ; Environmental impacts; Genetics; Glacier lakes; Ice shelves; Lake ice; Lake stratification; Lakes; Melting; Methane; Microbial ecology; Microorganisms; Permafrost; Plankton; Plant distribution; Protozoa; Puddles; Rivers; Sea ice; Snow; Soil temperature; Soils; Spatial distribution; Springs (Hydrology); Thawing; Thermokarst; Thickness; Tundra ponds; Viruses; Wildlife habitat

G0813, G03, G0826, G0812
Ayles Fiord, Nunavut; Bylot Island, Nunavut; Disraeli Fiord, Nunavut; Expedition Fiord region, Nunavut; Kuujjuarapik region, Québec; M'Clintock Inlet, Nunavut; Mackenzie Delta, N.W.T.; Markham Fiord, Nunavut; Milne Fiord, Nunavut; Milne Ice Shelf, Nunavut; Nansen Sound, Nunavut; Petersen Bay, Nunavut; Phillips Inlet, Nunavut; Serson Ice Shelf, Nunavut; Umiujaq region, Québec; Ward Hunt Ice Shelf, Nunavut; Ward Hunt Island, Nunavut; Yelverton Bay, Nunavut


Allochthonous inputs of riverine picocyanobacteria to coastal waters in the Arctic Ocean   /   Waleron, M.   Waleron, K.   Vincent, W.F.   Wilmotte, A.
(Microorganisms in cold environments / Edited by R. Margesin and M.M. Häggblom. FEMS microbiology, ecology, v. 59, no. 2, Feb. 2007, p. 356-365, ill.)
References.
MARE contribution no. 94.
Contribution to the Canadian Arctic Shelf Exchange Study (CASES).
ASTIS record 60645.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/204.pdf
Web: doi:10.1111/j.1574-6941.2006.00236.x
Libraries: ACU

The observed onset of climate change at high northern latitudes has highlighted the need to establish current baseline conditions in the Arctic Ocean, and has raised concern about the potential for the invasion and growth of biota that have warm temperature optima, such as cyanobacteria. In this study, we used 16S rRNA gene sequences as a molecular marker to evaluate the hypothesis that Arctic rivers provide a major inoculum of cyanobacteria into the coastal Arctic Ocean. Surface samples were collected along a transect extending from the Mackenzie River (Northwest Territories, Canada), across its estuary, to 200 km offshore at the edge of the perennial Arctic pack ice (Beaufort Sea). The highest picocyanobacteria concentrations occurred in the river, with concentrations an order of magnitude lower at offshore marine stations. The 16S rRNA gene clone libraries of five surface samples and five strains along this gradient showed that the cyanobacterial sequences were divided into eight operational taxonomic units (OTUs), six OTUs closely related to freshwater and brackish Synechococcus and two OTUs of filamentous cyanobacteria. No typically marine Synechococcus sequences and no Prochlorococcus sequences were recovered. These results are consistent with the hypothesis of an allochthonous origin of picocyanobacteria in the coastal Arctic Ocean, and imply survival but little net growth of picocyanobacteria under the present conditions in northern high-latitude seas. (Au)

D, E, H, F
Bacteria; Canadian Arctic Shelf Exchange Study; Climate change; Cyanophyceae; Effects of climate on plants; Environmental impacts; Fluorometry; Fresh-water flora; Genetics; Marine flora; Plant distribution; Plant taxonomy; River discharges; Sediment transport; Suspended solids

G0812, G03, G07, G0815
Amundsen Gulf, N.W.T.; Arctic Ocean; Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Franklin Bay, N.W.T.; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.


Approaching freshet beneath landfast ice in Kugmallit Bay on the Canadian Arctic Shelf : evidence from sensor and ground truth data   /   Walker, T.R.   Grant, J.   Jarvis, P.
(Arctic, v. 61, no. 1, Mar. 2008, p. 76-86, ill., maps)
References.
ASTIS record 63676.
Languages: English
Web: http://pubs.aina.ucalgary.ca/arctic/Arctic61-1-76.pdf
Web: doi:10.14430/arctic8
Libraries: ACU

The Mackenzie River is the largest river in the North American Arctic. Its huge freshwater and sediment load impacts the Canadian Beaufort Shelf, transporting large quantities of sediment and associated organic carbon into the Arctic Ocean. The majority of this sediment transport occurs during the freshet peak flow season (May to June). Mackenzie River-Arctic Ocean coupling has been widely studied during open water seasons, but has rarely been investigated in shallow water under landfast ice in Kugmallit Bay with field-based surveys, except for those using remote sensing. We observed and measured sedimentation rates (51 g/m²/d) and the concentrations of chlorophyll a (mean 2.2 µg/L) and suspended particulate matter (8.5 mg/L) and determined the sediment characteristics during early spring, before the breakup of landfast ice in Kugmallit Bay. We then compared these results with comparable data collected from the same site the previous summer. Comparison of organic quality in seston and trapped material demonstrated substantial seasonal differences. The subtle changes in biological and oceanographic variables beneath landfast ice that we measured using sensors and field sampling techniques suggest the onset of a spring melt occurring hundreds of kilometres farther south in the Mackenzie Basin. (Au)

F, B, J, A, G, D, F, H, E
Algae; Bathymetry; Bottom sediments; Breakup; Carbon; Chemical oceanography; Chlorophyll; Climate change; Continental shelves; Data buoys; Environmental impacts; Estuaries; Fast ice; Floods; Food chain; Mathematical models; Measurement; Melting; Nitrogen; Ocean currents; Ocean temperature; Oceanographic instruments; Phytoplankton; Primary production (Biology); River deltas; River discharges; River ice; Rivers; Salinity; Sea ice; Sea ice ecology; Seasonal variations; Sediment transport; Sedimentation; Spatial distribution; Suspended solids; Temporal variations; Thickness

G0812, G07, G03
Arctic Ocean; Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Kugmallit Bay, N.W.T.; Mackenzie Delta, N.W.T.; Mackenzie River, N.W.T.


Suspended sediment and erosion dynamics in Kugmallit Bay and Beaufort Sea during ice-free conditions   /   Walker, T.R.   Grant, J.   Cranford, P.   Lintern, D.G.   Hill, P.   Jarvis, P.   Barrell, J.   Nozais, C.
(Sea ice and life in a river-influenced Arctic shelf ecosystem / Edited by W.F. Vincent and C. Pedrós-Alió. Journal of marine systems, v. 74, no. 3-4, Dec. 2008, p. 794-809, ill., maps)
References.
ASTIS record 65239.
Languages: English
Web: doi:10.1016/j.jmarsys.2008.01.006
Libraries: ACU

The Mackenzie River is the largest river on the North American side of the Arctic and its huge freshwater and sediment load impacts the Canadian Beaufort Shelf. Huge quantities of sediment and associated organic carbon are transported in the Mackenzie plume into the interior of the Arctic Ocean mainly during the freshet (May to September). Changing climate scenarios portend increased coastal erosion and resuspension that lead to altered river-shelf-slope particle budgets. We measured sedimentation rates, suspended particulate matter (SPM), particle size and settling rates during ice-free conditions in Kugmallit Bay (3-5 m depth). Additionally, measurements of erosion rate, critical shear stress, particle size distribution and resuspension threshold of bottom sediments were examined at four regionally contrasting sites (33-523 m depth) on the Canadian Beaufort Shelf using a new method for assessing sediment erosion. Wind induced resuspension was evidenced by a strong relationship between SPM and wind speed in Kugmallit Bay. Deployment of sediment traps showed decreasing sedimentation rates at sites along an inshore-offshore transect ranging from 5400 to 3700 g/m²/d. Particle settling rates and size distributions measured using a Perspex settling chamber showed strong relationships between equivalent spherical diameter (ESD) and particle settling rates (r²=0.91). Mean settling rates were 0.72 cm/s with corresponding ESD values of 0.9 mm. Undisturbed sediment cores were exposed to shear stress in an attempt to compare differences in sediment stability across the shelf during September to October 2003. Shear was generated by vertically oscillating a perforated disc at controlled frequencies corresponding to calibrated shear velocity using a piston grid erosion device. Critical (Type I) erosion thresholds (u*) varied between 1.1 and 1.3 cm/s with no obvious differences in location. Sediments at the deepest site Amundsen Gulf displayed the highest erosion rates (22-54 g/m²/min) with resuspended particle sizes ranging from 100 to 930 µm for all sites. There was no indication of biotic influence on sediment stability, although our cores did not display a fluff layer of unconsolidated sediment. Concurrent studies in the delta and shelf region suggest the importance of a nepheloid layer which transports suspended particles to the slope. Continuous cycles of resuspension, deposition, and horizontal advection may intensify with reduction of sea ice in this region. Our measurements coupled with studies of circulation and cross-shelf exchange allow parameterization and modeling of particle dynamics and carbon fluxes under various climate change scenarios. (Au)

D, B, H, A, E, F
Bottom sediments; Carbon; Chlorophyll; Continental shelves; Cores; Density; Erosion; Fluorometry; Interstitial water; Nitrogen; Ocean currents; Ocean temperature; River discharges; Salinity; Sea water; Sediment transport; Sedimentation; Size; Soil texture; Spatial distribution; Stress; Suspended solids; Velocity; Winds

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Kugmallit Bay, N.W.T.; Mackenzie Trough, Canadian Beaufort Sea; Tuktoyaktuk Harbour, N.W.T.


Seasonality in the response of sea ice and upwelling to wind forcing in the southern Beaufort Sea   /   Wang, Q.   Ingram, R.G. [Supervisor]   Hsieh, W. [Supervisor]
Vancouver, B.C. : University of British Columbia, 2007.
xi, 89 p. : ill., maps ; 28 cm.
Thesis (M.Sc.) - University of British Columbia, Vancouver, B.C., 2007.
Appendix.
References.
ASTIS record 74984.
Languages: English
Web: https://circle.ubc.ca/bitstream/handle/2429/392/ubc_2008_spring_wang_qiang.pdf?sequence=1
Libraries: OONL

The seasonal pattern of ice motion in response to wind forcing and potential consequences to upwelling on the Mackenzie Shelf are considered using satellite-derived ice motion data from the National Snow and Ice Data Center and the NCEP 10 m wind data. The frequency of strong upwelling-favorable alongshore ice motion is high in early winter (November and December) compared to middle and late winter (January to May). For periods when the alongshore component of the wind is upwelling-favorable, the ratio of ice drift divided by wind speed on the Mackenzie Shelf is 0.024 in November and 0.008 in March; we conjecture that this ratio decreases as winter progresses because the internal ice stress becomes stronger as both ice thickness and ice concentration increase. This constitutes a possible 10-fold decrease in the seasonal transmission of wind stress to the underlying water from November to March. This ratio in May (0.015) is higher than that in March. We suggest that it is because the internal ice stress becomes weaker as ice concentration decreases on the Mackenzie Shelf in May. Hence, under the same wind forcing, the potential for winter upwelling on Mackenzie Shelf may be enhanced if climate warming results in reduced ice thickness and/or ice concentration. Numerical model results show that the stress on the shelf could be reduced because of the internal ice stress from the pack ice over the deep ocean when the ice moves like a rigid body. We found that the model results are not realistic when the ice strength is 5,000 N/m². When the ice strength is 27,500 N/m², the model results are more realistic. (Au)

D, G, E, J
Boundary layers; Climate change; Effects of climate on ice; Ice cover; Mathematical models; Movement; Ocean currents; Ocean-atmosphere interaction; Pack ice; Satellite photography; Sea ice; Seasonal variations; Stress; Theses; Thickness; Water masses; Winds

G07
Canadian Beaufort Sea


Archaea in particle-rich waters of the Beaufort Shelf and Franklin Bay, Canadian Arctic : clues to an allochthonous origin?   /   Wells, L.E.   Cordray, M.   Bowerman, S.   Miller, L.A.   Vincent, W.F.   Deming, J.W.
(Limnology and oceanography, v. 51, no. 1, Jan. 2006, p. 47-59, ill., map)
References.
ASTIS record 62006.
Languages: English

We used 4',6-diamidino-2-phenylindole (DAPI) staining and fluorescent in situ hybridization to examine total bacterioplankton and archaeal distributions in surface waters and in deeper nepheloid layers and particle-poor waters across the Beaufort Shelf of the Canadian Arctic, including the Mackenzie River and Kugmallit Bay, as well as more distant Franklin Bay. Although the regional distribution of bacterioplankton was best explained by salinity (r(s) = -0.89, n = 28, p < 0.001) and indicators of primary production (chlorophyll a (Chl a), total organic carbon, and the ratio of Chl a to particulate organic carbon (Chl a:POC)), that of Archaea instead reflected measures of particulate matter, specifically microscopically determined particle concentration (r(s) = 0.85, n = 30, p < 0.001), suspended particulate matter, POC, particulate organic nitrogen (PON), and the beam attenuation coefficient. Moreover, when compared with similarly deep particle-poor waters, nepheloid layers were significantly enriched in Archaea (median concentration of 6.00 × 10**4/mL (15.5% of bacterioplankton) vs. 1.79 × 10**4/mL (3.6%); p < 0.05), but not total bacterioplankton. The relationship between Archaea and particles, the dominance of the Mackenzie River as the regional particle source, the detection of highest archaeal concentrations (11.5-14.4 × 10**4/mL) in the river, and the highly significant correlation (r(s) = 0.97, n = 12, p < 0.001) between Archaea in particle-rich waters and PON (the river providing the upper end member) suggest that many of these Archaea derive from the river. (Au)

I, H, D, F
Animal distribution; Archaea; Bacteria; Carbon; Chlorophyll; Fluorometry; Measurement; Nitrogen; Ocean temperature; Plankton; Plant distribution; Primary production (Biology); Rivers; Salinity; Sea water; Spatial distribution; Suspended solids; Water masses

G07, G0815, G0812
Canadian Beaufort Sea; East Channel (Mackenzie River), N.W.T.; Franklin Bay, N.W.T.; Kugmallit Bay, N.W.T.; Middle Channel (Mackenzie River), N.W.T.


Modelled and measured dynamics of viruses in Arctic winter sea-ice brines   /   Wells, L.E.   Deming, J.W.
(Environmental microbiology, v. 8, no. 6, June 2006, p.1115-1121, ill.)
References.
ASTIS record 63270.
Languages: English
Web: doi:10.1111/j.1462-2920.2006.00984.x
Libraries: ACU

We describe a model based on diffusion theory and the temperature-dependent mechanism of brine concentration in sea ice to argue that, if viruses partition with bacteria into sea-ice brine inclusions, contact rates between the two can be higher in winter sea ice than in seawater, increasing the probability of infection and possible virus production. To examine this hypothesis, we determined viral and bacterial concentrations in select winter sea-ice horizons using epifluorescence microscopy. Viral concentrations ranged from 1.6 to 82 × 10**6/ml of brine volume of the ice, with highest values in brines from coldest (-24 to -31°C) ice horizons. Calculated virus-bacteria contact rates in underlying -1°C seawater were similar to those in brines of -11°C ice but up to 600 times lower than those in ice brines at or below -24°C. We then incubated native bacterial and viral assemblages from winter sea ice for 8 days in brine at a temperature (-12°C) and salinity (160 psu) near expected in situ values, monitoring their concentrations microscopically. While different cores yielded different results, consistent with known spatial heterogeneity in sea ice, these experiments provided unambiguous evidence for viral persistence and production, as well as for bacterial growth, in -12°C brine. (Au)

J, H, G, D
Bacteria; Biomass; Chlorophyll; Cores; Effects monitoring; Fast ice; Fluorometry; Mathematical models; Measurement; Melting; Metabolism; Microbial ecology; Physical properties; Plant growth; Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Temperature; Viruses; Winter ecology

G0815
Franklin Bay, N.W.T.


Characterization of a cold-active bacteriophage on two psychrophilic marine hosts   /   Wells, L.E.   Deming, J.W.
(Aquatic microbial ecology, v. 45, no. 1, Oct. 2006, p. 15-29, ill.)
References.
ASTIS record 63363.
Languages: English
Web: doi:10.3354/ame045015
Libraries: AEU

A cold-active bacteriophage designated 9A was isolated against Colwellia psychrerythraea Strain 34H at near in situ temperature (-1°C) by enrichment of seawater from an Arctic nepheloid layer, using a newly developed isothermal overlay technique. Phage 9A is classified as a Siphoviridae with a genome size of 80 to 90 kb. In addition to 34H, 9A infects C. demingiae ACAM 459T; no other hosts (of 22 tested) were identified. In replete media, 9A formed plaques on 34H from -6 to 4°C and on C. demingiae from -6 to 8°C; the temperature range of plaque formation on 34H could be extended to 8°C by prior host starvation. An indirect plating method and microscopic evaluation also determined phage production at temperatures between -13 and -10°C. At -1°C, 34H had a broader salinity range of plaque formation than C. demingiae: 20 to 50 (but not 65) psu vs. 27 to 34 (but not 50) psu. As monitored by epifluorescence microscopy, phage production by 34H was observed at 1, 10, 100 and 200 atm (all at -1°C), but not at 400 or 600 atm. The 9A-34H system commonly had a low efficiency of plating (EOP; typically ~1%) which varied with culture age. Despite repeated attempts, no meaningful adsorption rate could be determined at -1 or 8°C. This result, the low EOP, and the effect of starvation on plaque formation suggest that fluctuating host phenotypes may play an important role in the dynamics of this system. One-step growth curves (using 34H as host) revealed a longer latent period (4 to 5 vs. 2.5 to 3 h) and greater burst size (55 vs. 5) at -1 than 8°C; at temperatures between -10 and -12°C, the estimated latent period was 5-10 d and the burst size 5. At both -1 and 8°C, rise times were comparable to latent periods. Although the cycle from infection to burst at -1°C required only 10 to 20% of the generation time of 34H at this temperature, the amount of viral DNA synthesized was comparable to the size of the host genome, suggesting very efficient and cold-active virus-encoded enzymes. (Au)

J, G, H, D
Amino acids; Bioassays; Carbon; Carbon cycling; Cold adaptation; Enzymes; Genetics; Marine ecology; Microbial ecology; Microorganisms; Microscopes; Plant anatomy; Plant growth; Plant taxonomy; Psychrophilic bacteria; Salinity; Sea ice; Sea ice ecology; Sea water; Viruses

G0815
Franklin Bay, N.W.T.


Effects of temperature, salinity and clay particles on inactivation and decay of cold-active marine Bacteriophage 9A   /   Wells, L.E.   Deming, J.W.
(Aquatic microbial ecology, v. 45, no. 1, Oct. 2006, p. 31-39, ill.)
References.
ASTIS record 63364.
Languages: English
Web: doi:10.3354/ame045031
Libraries: AEU

The effects of temperature, salinity and clay particles on the inactivation and decay of the cold-active bacteriophage 9A, isolated from particle-rich Arctic seawater, were examined using a plating technique to evaluate infectivity (inactivation) and epifluorescence microscopy to measure phage concentrations (decay). Phage 9A was rapidly inactivated over a temperature test range of 25 to 55°C in marine broth (salinity of 36 psu), with half-lives ranging from <10 min at 25°C to ~1 min at 32.5°C and too rapid to measure at >= 35°C, making it among the most thermolabile phages. When salinity was varied at 30°C, the inactivation rates in brackish (21 psu) and briny (161 psu) broth were indistinguishable from that in marine broth (p > 0.20). At the environmentally relevant temperature of -1°C, however, loss of infectivity in briny broth was 3 to 4 times greater than in marine or brackish broth. As commonly observed, viral decay determined microscopically often substantially underestimated loss of infectivity: at 30°C, loss of infectivity exceeded the viral decay rate by approximately 1000-fold, while at -1°C, microscopic counts did not detect any of the losses observed by plaque assay. Under conditions comparable to a winter sea-ice brine inclusion (-12°C and 161 psu), however, plating and microscopy were in substantive agreement, indicating relatively minor losses of 16 to 34% losses over a 5 wk period. Illite, kaolinite or montmorillonite clays had no statistically significant effect on phage inactivation as a function of temperature or salinity, although rates tended to be slower in the presence of the clays. In general, our results emphasize the importance of working with cold-active phages under environmentally-relevant conditions of temperature and salinity. They also imply decay processes that involve viral proteins rather than nucleic acids; as a result, affected viruses may be recalcitrant to reactivation by known host-based repair mechanisms. (Au)

J, H, G, B
Bioassays; Clay; Cold adaptation; Cyanophyceae; Energy budgets; Enzymes; Fluorometry; Kaolinite; Marine ecology; Microbial ecology; Proteins; Psychrophilic bacteria; Salinity; Sea water; Suspended solids; Temperature; Viruses

G07
Canadian Beaufort Sea


Significance of bacterivory and viral lysis in bottom waters of Franklin Bay, Canadian Arctic, during winter   /   Wells, L.E.   Deming, J.W.
(Aquatic microbial ecology, v. 43, no. 3, Oct. 2006, p. 209-221, ill.)
References.
ASTIS record 63366.
Languages: English
Web: doi:10.3354/ame043209
Libraries: AEU

Little information is currently available about water column microbial processes or mortality during Arctic winter. To address this paucity, we used epifluorescence microscopy and dilution experiments to determine the abundance of flagellates, bacteria and virus-like particles (VLP) and the rates of bacterial growth, bacterivory and virus-induced mortality in subzero-temperature bottom waters (<= 230 m) of Franklin Bay during February and March 2004, when ice-covered surface waters were highly oligotrophic (maximum chlorophyll a value of 0.09 µg/l). We focused on bottom waters due to the possible importance of sediment resuspension as a source of organic matter. While flagellates were present at low densities (1.5 to 3.1 ×10²/ml), bacterial concentrations resembled those from other seasons in the region and increased over the 5 wk sampling period, from 1.4 × 10**5 to 3.0 × 10**5/ml. VLPs were typically an order of magnitude more abundant than bacteria (range of 1.4 to 4.5 × 10**6 VLP/ml) and, like the fraction of particle-associated bacteria (but not total bacteria), correlated with particulate organic carbon concentration (rs= 0.82, p < 0.04, n = 7). Grazing rates, whether measured in dilution experiments or calculated from flagellate abundance, were low or undetectable (maximum of -0.004/h). Of 3 parallel experiments, 2 yielded substantial virus-induced mortality (-0.006 to -0.015/h) comparable to or exceeding the intrinsic bacterial growth rate (0.010/h) in both experiments) and suggesting viruses were the more important agents of bacterial mortality under these conditions. Using a viral reduction approach, VLP production measured in the water column or ice-moored sediment traps was commonly low (0.3 to 7.7 × 10**4 VLP/ml/h) or undetectable, highly variable among replicates and, when measurable, implied viral turnover times between 0.9 and 12 d. In general, our results show that, despite the oligotrophy of Arctic winter, bottom water bacterial communities can remain active and subject to viral predation. (Au)

J, D, H, I, G
Algae; Bacteria; Biomass; Carbon; Carbon cycling; Chemical oceanography; Chlorophyll; Energy budgets; Fluorometry; Food chain; Grazing; Growth; Ice cover; Marine ecology; Measurement; Microbial ecology; Microorganisms; Ocean floors; Oxygen; Particulate organic matter; Predation; Primary production (Biology); Sea ice; Sea water; Suspended solids; Temporal variations; Viruses; Water masses; Winter ecology; Zooplankton

G0815, G15
Antarctic waters; Franklin Bay, N.W.T.


Accurate estimation of viral abundance by epifluorescence microscopy   /   Wen, K.   Ortmann, A.C.   Suttle, C.A.
(Applied and environmental microbiology, v. 70, no. 7, July 2004, p.3862-3867, ill.)
References.
ASTIS record 74730.
Languages: English
Web: doi:10.1128/AEM.70.7.3862-3867.2004
Libraries: ACU

Virus enumeration by epifluorescence microscopy (EFM) is routinely done on preserved, refrigerated samples. Concerns about obtaining accurate and reproducible estimates led us to examine procedures for counting viruses by EFM. Our results indicate that aldehyde fixation results in rapid decreases in viral abundance. By 1 h postfixation, the abundance dropped by 16.4% ±5.2% (n = 6), and by 4 h, the abundance was 20 to 35% lower. The average loss rates for glutaraldehyde- and formaldehyde-fixed samples over the first 2 h were 0.12 and 0.13 h-1, respectively. By 16 days, viral abundance had decreased by 72% (standard deviation, 6%; n=6). Aldehyde fixation of samples followed by storage at 4°C, for even a few hours, resulted in large underestimates of viral abundance. The viral loss rates were not constant, and in glutaraldehyde- and formaldehyde-fixed samples they decreased from 0.13 and 0.17/h during the first hour to 0.01/h between 24 and 48 h. Although decay rates changed over time, the abundance was predicted by using separate models to describe decay over the first 8 h and decay beyond 8 h. Accurate estimates of abundance were easily made with unfixed samples stained with Yo-Pro-1, SYBR Green I, or SYBR Gold, and slides could be stored at -20°C for at least 2 weeks or, for Yo-Pro-1, at least 1 year. If essential, samples can be fixed and flash frozen in liquid nitrogen upon collection and stored at -86°C. Determinations performed with fixed samples result in large underestimates of abundance unless slides are made immediately or samples are flash frozen. If protocols outlined in this paper are followed, EFM yields accurate estimates of viral abundance. (Au)

H, I
Fluorometry; Logistics; Measurement; Specifications; Temporal variations; Viruses

G05, G0821
Fraser River, British Columbia; Vancouver waters, British Columbia


Tidal height retrieval using globally corrected GPS in the Amundsen Gulf region of the Canadian Arctic   /   Wert, T.D.   Dare, P. [Supervisor]
Fredericton, N.B. : Universiy of New Brunswick, 2004.
ix, 129 p. : ill., maps ; 28 cm.
(ProQuest Dissertations & Theses publication, no. MR15143)
ISBN 0-494-15143-9
Thesis (M.Sc.) - University of New Brunswick, Fredericton, N.B., 2004.
Appendices.
References.
Indexed from a PDF file acquired from ProQuest Dissertations & Theses.
ASTIS record 60655.
Languages: English
Web: http://www.omg.unb.ca/omg/papers/Travis_Final_Thesis.pdf
Libraries: OONL

The recent evolution of global Wide Area Differential GPS (WADGPS) networks has greatly increased the already high level of interest in GPS technologies by the hydrographic community. This thesis evaluates one of these WADGPS receivers, the C&C Technologies Globally Corrected GPS (GcGPS) C-Nav receiver, as an instrument for tidal height retrieval in the Canadian Arctic. The C-Nav was mounted aboard the Canadian Coast Guard Ship (CCGS) Amundsen for her 14 month over-wintering expedition in the Northwest Passage. C-Nav height data were collected in Franklin Bay, NWT, over February to April, 2004. Knudsen K320 sub-bottom profiling sonar depth data was collected as a true vertical reference. The 1 Hz C-Nav data were processed and decimated down to 6 minute epochs, thus speeding the filter processing to obtain real-time data latency. The standard deviation of the residuals between the C-Nav and K320 tidal signals was 4.3 cm. This level of positioning is commensurate with International Hydrographic Organization (IHO) Special Order surveys. In addition, the filtered C-Nav height signal was processed using Least Squares Spectral Analysis (LSSA) to define the tidal constituents in terms of amplitude and phase. The C-Nav derived constituent amplitudes are within centimetres of the K320 determined values, and the historical constituent data for Franklin Bay. (Au)

D, A
Amundsen (Ship); Canadian Arctic Shelf Exchange Study; Forecasting; Geographical positioning systems; Hydrographic surveys; Instruments; Mathematical models; Measurement; Oceanography; Sonar; Specifications; Theses; Tides

G0815
Amundsen Gulf, N.W.T.; Franklin Bay, N.W.T.


Joint effects of wind and ice motion in forcing upwelling in Mackenzie Trough, Beaufort Sea   /   Williams, W.J.   Carmack, E.C.   Shimada, K.   Melling, H.   Aagaard, K.   Macdonald, R.W.   Ingram, R.G.
(Continental shelf research, v. 26, no. 19, Dec. 2006, p.2352-2366, ill., maps)
References.
ASTIS record 63272.
Languages: English
Web: doi:10.1016/j.csr.2006.06.012
Libraries: ACU

Mackenzie Trough, a cross shelf canyon in the Beaufort Sea shelf, is shown to be a site of enhanced shelf-break exchange via upwelling caused by wind- and ice-driven ocean surface-stresses. To characterize flow within the Trough, we analyze current meter mooring data and concurrent wind and ice velocity data from 1993 to 1996, and show CTD/ADCP sections from 2002. Mackenzie Trough is approximately 400 m deep and 60 km wide, but dynamically it is only 2-3 times the baroclinic Rossby radius at its mouth, and patterns of upwelling and downwelling flow within the canyon are similar to dynamically ‘narrow’ canyons. Large upwelling events within the canyon are associated with wind in the short ice-free summer season and with ice motion in winter. Ice motion does not necessarily reflect the wind-stress because of internal ice stresses that differentially block downwelling-causing ice motion. The asymmetry between upwelling and downwelling flow within the canyon combined with the predominance of upwelling-causing ice motion, suggests that Mackenzie Trough is a conduit for deeper, nutrient-rich water to the shelf. (Au)

D, E, G, A, H
Bathymetry; Boundary layers; Continental shelves; Flow; Mathematical models; Measurement; Movement; Ocean currents; Ocean temperature; Oceanographic instruments; Pack ice; Primary production (Biology); Salinity; Sea ice; Stress; Submarine topography; Surface properties; Temporal variations; Velocity; Water masses; Winds

G07, G0812
Alaskan Beaufort Sea; Canadian Beaufort Sea; Mackenzie Trough, Canadian Beaufort Sea; Pelly Island, N.W.T.


The wind- and ice-driven response of the Mackenzie shelf and Amundsen Gulf   /   Williams, W.J.   Carmack, E.C.   Ingram, G.   Gratton, Y.
(Meetings abstracts, 2006 Ocean Sciences Meeting, Honolulu, Hawaii, 20-24 February 2006. Eos (Washington, D.C.), v. 87, no. 36, suppl., 5 Sept. 2006, p.OS337-OS338)
Abstract of an oral presentation (OS34N-01).
Abstracts can be found online through the AGU Meeting Abstract Database: www.agu.org/meetings/abstract_db.shtml.
ASTIS record 68522.
Languages: English
Libraries: ACU

An extensive moored array was deployed along the shelf-break of the Mackenzie Shelf and within Amundsen Gulf from September 2003 to September 2004 as part of the Canadian Arctic Shelf Exchange Study (CASES). We use data from this moored array to describe the ocean's response to surface-stress, focusing on the effect of individual events and the relative contributions from wind and ice-generated stress. Of particular importance are shelf-break exchange processes which are critical to the development of the Arctic halocline and to the flux of deep water onto the shelves. Upwelling of nutrient-rich water to the shelf can aid primary production and appears to be enhanced by topographic irregularities such as cross-shelf canyons. Near Cape Bathurst, the Mackenzie Shelf abruptly narrows and ends at Amundsen Gulf; thus along-shelf flow generated by upwelling-directed surface stress will force enhanced upwelling near the Cape. (Au)

D, E, G
Bathymetry; Continental shelves; Flow; Ocean currents; Oceanographic instruments; Oceanography; Sea ice; Stress; Submarine topography; Water masses; Winds

G07, G0815
Amundsen Gulf, N.W.T.; Bathurst, Cape, waters, N.W.T.; Mackenzie Estuary, N.W.T./Yukon


Physical oceanography of polynyas   /   Williams, W.J.   Carmack, E.C.   Ingram, R.G.
(Polynyas : windows to the world / Edited by W.O. Smith and D.G. Barber. Elsevier oceanography series, v. 74, 2007, ch. 2, p. 55-85, ill.)
References.
ASTIS record 63895.
Languages: English
Web: doi:10.1016/S0422-9894(06)74002-8
Libraries: ACU

Physical processes related to polynya formation are reviewed and selected examples from both the Arctic and the Antarctic seas are given. Polynyas are categorized by dividing them into mechanically and convectively forced systems, recognizing that most polynyas are formed by a confluence of two or more physical factors, and that positive feedback processes also impact formation. Polynyas strongly impact the regional oceanography. Those that are initiated by mechanical forcing from the wind, for example, may produce large quantities of ice and brine. Dense water formed in this manner can then migrate via Ekman layers, gravity currents, and eddying motions across the shelf, and drain into the deep ocean. Under scenarios of global warming, a climatologically retreating ice edge will alter the size and distribution of polynyas. In the Arctic and on the Antarctic Peninsula, the general pattern of polynyas relative to the ice edge is likely to be similar. (Au)

G, D, E, F, A, J
Albedo; Bathymetry; Biological productivity; Classification; Climate change; Continental shelves; Density; Environmental impacts; Fast ice; Flow; Formation ; Frazil ice; Glaciers; Growth; Heat budgets; Heat transmission; Ice leads; Ice shelves; Icebergs; Ocean currents; Ocean temperature; Oceanography; Polynyas; Salinity; Sea ice; Size; Solar radiation; Spatial distribution; Stamukhi; Strength; Submarine topography; Thickness; Tides; Velocity; Water masses; Winds

G02, G15
Antarctic waters; Arctic waters


Kugmallit Valley as a conduit for cross-shelf exchange on the Mackenzie shelf in the Beaufort Sea   /   Williams, W.J.   Melling, H.   Carmack, E.C.   Ingram, R.G.
(Journal of geophysical research, v.113, no. C2, C02007, Feb. 2008, 13 p., ill., maps)
References.
ASTIS record 64124.
Languages: English
Web: doi:10.1029/2006JC003591
Libraries: ACU

Kugmallit Valley spans the midsection of a transect across the Mackenzie Shelf of the Beaufort Sea. Its greatest relief is 20 m, and its width is 20 km. Using a yearlong record of ice drift, ocean current, temperature, and salinity acquired near the center of the valley, we describe a pattern of flow that is correlated with wind stress and ice motion and discuss its similarity to flow within larger submarine canyons that cut through the shelf break. As in such canyons, there is enhanced cross-shelf transport within Kugmallit Valley during upwelling-favorable surface stress. The data also document the down-valley flow of dense water from a flaw lead. (Au)

D, E, G, A
Bathymetry; Boundary layers; Continental shelves; Fast ice; Flow; Ice cover; Ice leads; Mathematical models; Measurement; Movement; Ocean currents; Ocean temperature; Oceanographic instruments; Pack ice; Salinity; Sea ice; Seasonal variations; Stamukhi; Stress; Submarine topography; Surface properties; Temporal variations; Velocity; Water masses; Winds

G07, G0812
Canadian Beaufort Sea; Kugmallit Valley, Canadian Beaufort Sea; Pelly Island, N.W.T.


The relation between productivity and species diversity in temperate-Arctic marine ecosystems   /   Witman, J.D.   Cusson, M.   Archambault, P.   Pershing, A.J.   Mieszkowska, N.
(Coordinating research on the North Atlantic / Edited by C.W. Cunningham. Ecology, v. 89, no. 11, suppl., Nov. 2008, p. S66-S80, ill., map)
References.
A supplement is available online through Ecological Archives.
ASTIS record 65882.
Languages: English
Web: http://esapubs.org/archive/ecol/E089/186/supplement.txt
Web: doi:10.1890/07-1201.1
Libraries: ACU

Energy variables, such as evapotranspiration, temperature, and productivity explain significant variation in the diversity of many groups of terrestrial plants and animals at local to global scales. Although the ocean represents the largest continuous habitat on earth with a vast spectrum of primary productivity and species richness, little is known about how productivity influences species diversity in marine systems. To search for general relationships between productivity and species richness in the ocean, we analyzed data from three different benthic marine ecosystems (epifaunal communities on subtidal rock walls, on navigation buoys in the Gulf of St. Lawrence, and Canadian Arctic macrobenthos) across local to continental spatial scales (<20 to >1000 km) using a standardized proxy for productivity, satellite-derived chlorophyll a. Theoretically, the form of the function between productivity and species richness is either monotonically increasing or decreasing, or curvilinear (hump- or U-shaped). We found three negative linear and three hump-shaped relationships between chlorophyll and species richness out of 10 independent comparisons. Scale dependence was suggested by more prevalent diversity-productivity relationships at smaller (local, landscape) than larger (regional, continental) spatial scales. Differences in the form of the functions were more closely allied with community type than with scale, as negative linear functions were restricted to sessile epifauna while hump-shaped functions occurred in Arctic macrobenthos (mixed epifauna, infauna). In two of the data sets, (St. Lawrence epifauna and Arctic macrobenthos) significant effects of chlorophyll a co-varied with the effects of salinity, suggesting that environmental stress as well as productivity influences diversity in these marine systems. The co-varying effect of salinity may commonly arise in broad-scale studies of productivity and diversity in marine ecosystems when attempting to sample the largest range of productivity, often encompassing a coastal-oceanic gradient. (Au)

J, I, H, D
Animal distribution; Animal food; Animal population; Benthos; Biological productivity; Biology; Chlorophyll; Echinoderms; Evaporation; Identification; Invertebrates; Light; Marine ecology; Mussels; Ocean temperature; Photography; Predation; Primary production (Biology); Salinity; Satellite photography; Size; Spatial distribution

G0815, G07, G0814, G11
Canadian Beaufort Sea; Coronation Gulf, Nunavut; English Channel; Frobisher Bay, Nunavut; Hudson Bay; Icelandic waters; James Bay; Maine waters; St. Lawrence Estuary, Québec; St. Lawrence, Gulf of, Canada; Ungava, Baie d', Québec


Polar marine biology science in Portugal and Spain : recent advances and future perspectives   /   Xavier, J.C.   Barbosa, A.   Agusti, S.   Alonso-Sáez, L.   Alvito, P.   Ameneiro, J.   Ávila, C.   Baeta, A.   Canário, J.   Carmona, R.   Catry, P.   Ceia, F.   Clark, M.S.   Cristobo, F.J.   Cruz, B.   Duarte, C.M.   Figuerola, B.   Gili, J.-M.   Gonçalves, A.R.   Gordillo, F.J.L.   Granadeiro, J.P.   Guerreiro, M.   Isla, E.   Jiménez, C.   López-González, P.J.   Lourenço, S.   Marques, J.C.   Moreira, E.   Mota, A.M.   Nogueira, M.   Núnez-Pons, L.   Orejas, C.   Paiva, V.H.   Palanques, A.   Pearson, G.A.   Pedrós-Alió, C.   Pena Cantero, Á.L.   Power, D.M.   Ramos, J.A.   Rossi, S.   Seco, J.   Sane, E.   Serrão, E.A.   Taboada, S.   Tavares, S.   Teixidó, N.   Vaqué, D.   Valente, T.   Vázquez, E.   Vieira, R.P.   Vinegla, B.
(Main results from the XVII Iberian Symposium of Marine Biology Studies / Edited by Angel Borja, João Carlos Marques, Celia Olabarria and Victor Quintino. Journal of sea research, v. 83, Oct. 2013, p. 9-29)
Indexed a PDF file of an accepted, in press manuscript.
ASTIS record 77920.
Languages: English
Web: doi:10.1016/j.seares.2013.05.013
Libraries: ACU

Polar marine ecosystems have global ecological and economic importance because of their unique biodiversity and their major role in, between others, climate processes and commercial fisheries. Portugal and Spain have been highly active in a wide range of disciplines in marine biology of the Antarctic and the Arctic. The main aim of this paper is to provide a synopsis of some of the results and initiatives undertaken by Portuguese and Spanish polar teams within the field of marine sciences, particularly on the benthic and pelagic biodiversity (species diversity and abundance, including microbial), molecular, physiological and chemical mechanisms in polar organisms, conservation and ecology of top predators (particularly penguins, albatrosses and seals), pollutants and evolution of marine organisms, associated with major issues such as climate change, ocean acidification and UV radiation effects. Both countries have focused their polar research more in the Antarctic than in the Arctic. Portugal and Spain should encourage research groups to continue increasing their collaborations with other countries and develop multi-disciplinary research projects, as well as to maintain highly active within major organizations, such as the Scientific Committee for Antarctic Research (SCAR), the International Arctic Science Council (IASC) and the Association of Polar Early Career Scientists (APECS), and in international research projects. (Au)

D, I, H, E, J
Albatrosses; Climate change; Environmental impacts; Marine biology; Marine ecology; Marine fauna; Marine flora; Microorganisms; Penguins; Research; Research organizations; Seals (Animals); Wildlife management

G01
Antarctic waters; Arctic waters; Polar regions


Chromophoric dissolved organic matter (CDOM) in first-year sea ice in the western Canadian Arctic   /   Xi, H.   Aubry, C.   Zhang, Y.   Song, G.
(Marine chemistry, v.165, 20 Oct. 2014, p. 25-35, ill., map)
References.
Indexed from an accepted manuscript available online prior to publication.
ASTIS record 79985.
Languages: English
Web: doi:10.1016/j.marchem.2014.07.007
Libraries: ACU

We monitored the spatiotemporal progression of chromophoric dissolved organic carbon (CDOM) in first-year sea ice in the western Canadian Arctic between mid-March and early July 2008. CDOM abundance in bottom ice, as quantified by absorption coefficient at 325 nm, aCDOM(325), showed a positive, linear relationship with the concentration of chlorophyll a, being low at the start of ice algal accumulation, highly enriched during the peak bloom and early post-bloom, and depleted again during sea ice melting. Vertical profiles of CDOM in early and late spring were typically characterized by slight to moderate elevations at both the surface and bottom and rather constancy within the interior ice. In the ice algae-thriving mid-spring, L-type profiles prevailed due to extremely high CDOM in the lowermost 10-cm layer. Bottom-layer CDOM in landfast ice (aCDOM(325): 15.8/m) more than doubled that in drift ice (aCDOM(325): 6.6/m). CDOM in the ice cover, except the bottom layer, was generally lower than or similar to that in the under-ice surface water. Salinity accounted for 58% of the CDOM variability in drift ice having minimal terrestrial and ice algal signatures. CDOM absorption spectra of algae-rich bottom ice samples exhibited ultraviolet (UV) absorption shoulders attributable to mycosporine-like amino acids (MAAs). These compounds were readily photodegradable by solar UV radiation. Our results suggest 1) inclusion of organic solutes and in situ biological production are the dominant processes controlling the distribution of CDOM in sea ice in the study area, 2) biological production in bottom ice is a minor source of CDOM to the underlying surface water; 3) CDOM plays a critical role in shielding sympagic organisms in bottom ice against UV radiation; 4) the MAAs are effective photoprotectants only under low-UV conditions. (Au)

G, H, J, D, E
Algae; Biological productivity; Carbon; Colored dissolved organic matter; Effects monitoring; Fast ice; Ice cover; Melting; Ocean-atmosphere interaction; Salinity; Sea ice; Sea ice ecology; Sea water; Seasonal variations; Solar radiation; Spatial distribution; Temporal variations

G07
Banks Island waters, N.W.T.; Canadian Beaufort Sea; Darnley Bay, N.W.T.; Franklin Bay, N.W.T.


Photoproduction of carbon monoxide in first-year sea ice in Franklin Bay, southeastern Beaufort Sea   /   Xie, H.   Gosselin, M.
(Geophysical research letters, v. 32, no. 12, L12606, June 2005, 4 p., ill.)
References.
Franklin Bay is not part of the Beaufort Sea, it is part of Amundsen Gulf.
ASTIS record 60262.
Languages: English
Web: doi:10.1029/2005GL022803
Libraries: ACU

The concentration of carbon monoxide ([CO]) in first-year ice in Franklin Bay, southeastern Beaufort Sea, was ~40 times higher than in the underlying seawater and ~15 times higher than in the adjacent open water. The [CO] in the sea ice decreased with increasing depth and increased rapidly at the bottom where there was an abundance of ice microalgae. The depth distribution of [CO] was consistent with a photochemical source of this compound in sea ice, which was further inferred from the vertical profiles of the dissolved organic matter absorption coefficients and directly verified by incubation of ice samples refrozen from melted ice. Results from this study suggest that substantial photooxidation of organic matter occurs in sea ice. This process may affect the organic carbon cycle in the Arctic Ocean. The potential flux of CO from sea ice to the Arctic atmosphere is estimated to be 1.4 × 10**10 moles/a. (Au)

G, D, J, E, F
Albedo; Algae; Carbon cycling; Carbon monoxide; Chemical oceanography; Cores; Dissolved organic carbon; Fast ice; Mathematical models; Microbial ecology; Ocean-atmosphere interaction; Oceanography; Primary production (Biology); Sea ice; Sea ice ecology; Sea water; Shore ice; Snow

G0815, G03
Arctic Ocean; Franklin Bay, N.W.T.


Biological consumption of carbon monoxide in Delaware Bay, NW Atlantic and Beaufort Sea   /   Xie, H.   Zafiriou, O.C.   Umile, T.P.   Kieber, D.J.
(Marine ecology. Progress series (Halstenbek), v.290, Apr. 13, 2005, p. 1-14, ill., maps)
(Contribution - Woods Hole Oceanographic Institution, no. 11245)
References.
ASTIS record 63367.
Languages: English
Web: doi:10.3354/meps290001
Libraries: AEU

Microbial consumption is the dominant sink of oceanic carbon monoxide (CO), one of the major carbon-containing photoproducts of chromophoric dissolved organic matter in marine waters. This study presents first-order microbial CO consumption rate constants (kappa CO) determined using whole-water dark incubations in summer and fall in diverse marine ecosystems covering the Delaware Bay, NW Atlantic, and Beaufort Sea. The microbial CO consumption rate constant, kappa CO (mean ± SD) was 1.11 ± 0.76/h in the Delaware Bay, 0.33 ± 0.26/h in the coastal Atlantic, 0.099 ± 0.054/h in the open Atlantic, 0.040 ± 0.012/h in the coastal Beaufort Sea and 0.020 ± 0.0060/h in the offshore Beaufort Sea. The kappa CO in the Delaware Bay covaried with chlorophyll a concentration ([chl a]), rising with increasing salinity in the range 0 to 19 and diminishing with further increasing salinity. The kappa CO in the Beaufort Sea is significantly positively correlated with [chl a]. Both the Atlantic and cross-system data sets showed significant positive correlations between kappa CO and the product of [chl a] and water temperature, suggesting that [chl a] can be used as an indicator of CO-consuming bacterial activity in the areas and seasons sampled in this study. Microbial CO consumption was shown to follow Wright-Hobbie kinetics, with variable but low half-saturation concentrations: ~1 nM in the Beaufort Sea and Gulf Stream and 2 to 18 nM in the coastal NW Atlantic. These low half-saturation concentrations suggest that microbial CO consumption in seawater is at times partly saturated, and that some previous microbial CO consumption rates determined with the commonly used 14CO method could be underestimates due to the addition of 14CO as a tracer substrate. The present study provides valuable data for coastal and Arctic waters whose kappa CO values are poorly or not constrained, including extensive data on the dependence of kappa CO on the concentration of CO. (Au)

J, H, D, E
Bacteria; Carbon cycling; Carbon monoxide; Chemical oceanography; Chlorophyll; Dissolved organic carbon; Diurnal variations; Marine ecology; Measurement; Microbial ecology; Ocean temperature; Ocean-atmosphere interaction; Photosynthesis; Primary production (Biology); Salinity; Sea water; Seasonal variations

G07, G11, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Delaware Bay, Delaware; North Atlantic Ocean


Biogeochemical cycling in the Arctic Ocean : a story from carbon monoxide   /   Xie, H.
In: Arctic change 2008 : conference programme and abstracts, Québec (Qc), 9-12 December, 2008 = Arctic change 2008 : programme et résumés de la conference, Québec (Qc), 9-12 décembre 2008. - [Québec, Québec] : ArcticNet, 2008, p. 323
Abstract of a poster.
Indexed a PDF file from the Web.
ASTIS record 67388.
Languages: English
Web: http://www.arctic-change2008.com/pdf/ac-programme.pdf
Libraries: ACU

The distribution, photoproduction, microbial uptake, and air-sea exchange of carbon monoxide (CO) were investigated in open waters of the southeastern Beaufort Sea in autumn 2003 and spring 2004. Diurnal cycles of surface water CO concentration ([CO]) occurred in autumn but not in spring. In both seasons [CO] was well above air-equilibrium at most stations (maximum of 12,500% saturation) and dropped with depth to undetectable levels below 50 m. Mean surface water [CO] and CO water column burdens (0-50 m) were 0.45 nmol/L and 5.0 mmol/m² in autumn and 4.7 nmol/L and 64.8 mmol/m² in spring, and the sea-to-air CO flux was 33 times higher in spring. The efficiency of CO photoproduction correlated linearly with CDOM across the Mackenzie River estuary, the Mackenzie Shelf, and the Amundsen Gulf. Modeled water column CO photoproduction in spring was 15 times that in autumn (45.8 vs. 3.0 mmol/m²/d). Microbial CO uptake followed first-order kinetics in autumn while Hill-type, saturation, and inhibition kinetics were common in surface waters in spring. Biooxidation was the dominant CO loss term in autumn while gas exchange was almost equally important in spring. Higher photoproduction and slower bio-uptake in spring resulted in the wide autumn-spring differences in the [CO] distribution pattern and air-sea CO flux. This study reveals that CO cycling in cold northern waters differs both quantitatively and qualitatively from that in warmer seas. (Au)

D, E, J
Carbon cycling; Carbon monoxide; Chemical oceanography; Colored dissolved organic matter; Diurnal variations; Geochemistry; Light; Measurement; Microbial ecology; Ocean-atmosphere interaction; Primary production (Biology); Seasonal variations

G07, G0815
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Mackenzie Estuary, N.W.T./Yukon


Photobiogeochemical cycling of carbon monoxide in the southeastern Beaufort Sea in spring and autumn   /   Xie, H.   Bélanger, S.   Demers, S.   Vincent, W.F.   Papakyriakou, T.N.
(Limnology and oceanography, v. 54, no. 1, Jan. 2009, p. 234-249, ill., map)
References.
ASTIS record 68803.
Languages: English
Web: http://www.cen.ulaval.ca/warwickvincent/PDFfiles/246.pdf
Web: doi:10.4319/lo.2009.54.1.0234
Libraries: ACU

We investigated the distribution, photoproduction, microbial uptake, and air-sea exchange of carbon monoxide (CO), a key photoproduct of chromophoric dissolved organic matter (CDOM), in open waters of the southeastern Beaufort Sea in autumn 2003 and spring 2004. Diurnal cycles of surface water CO concentration ([CO]) occurred in autumn but not in spring. In both seasons [CO] was well above air-equilibrium at most stations (maximum of 12,500% saturation) and dropped with depth to undetectable levels below 50 m. Mean surface water [CO] and CO water-column burdens (0-50 m) were 0.45 nmol/L and 5.0 µmol/m² in autumn and 4.7 nmol/L and 64.8 µmol/m² in spring, and the sea-to-air CO flux was 33 times higher in spring. The efficiency of CO photoproduction correlated linearly with CDOM across the Mackenzie River estuary, the Mackenzie Shelf, and the Amundsen Gulf. Modeled water-column CO photoproduction in spring was 15 times that in autumn (45.8 vs. 3.0 µmol/m²/d). Microbial CO uptake followed first-order kinetics in autumn while Hill-type, saturation, and inhibition kinetics were common in surface waters in spring. Bio-oxidation was the dominant CO loss term in autumn while gas exchange was almost equally important in spring. Higher photoproduction and slower bio-uptake in spring resulted in the wide autumn-spring differences in the [CO] distribution pattern and air-sea CO flux. CO cycling in cold northern waters differs both quantitatively and qualitatively from that in warmer seas. (Au)

D, E, F, H, I
Bacteria; Biochemistry; Biomass; Carbon; Carbon cycling; Carbon monoxide; Chemical oceanography; Chlorophyll; Colored dissolved organic matter; Diurnal variations; Microorganisms; Ocean temperature; Ocean-atmosphere interaction; Photosynthesis; Plant physiology; Primary production (Biology); River discharges; Rivers; Salinity; Seasonal variations; Solar radiation; Spatial distribution; Spectroscopy; Velocity; Water masses; Winds

G07, G0812, G0815, G03
Amundsen Gulf, N.W.T.; Canadian Beaufort Sea; Mackenzie Estuary, N.W.T./Yukon; Mackenzie River, N.W.T.


Observations of snow water equivalent change on landfast first-year sea ice in winter using synthetic aperture radar data   /   Yackel, J.J.   Barber, D.G.
(IEEE transactions on geoscience and remote sensing, v. 45, no. 4, Apr. 2007, p.1005-1015, ill., maps)
References.
ASTIS record 65914.
Languages: English
Web: doi:10.1109/TGRS.2006.890418
Libraries: ACU

In this paper, we examine the utility of synthetic aperture radar (SAR) backscatter data to detect a change in snow water equivalent (SWE) over landfast first-year sea ice during winter at relatively cold temperatures. We begin by reviewing the theoretical framework for linking microwave scattering from SAR to the thermodynamic and electrical properties of first-year sea ice. Previous research has demonstrated that for a given ice thickness and air-temperature change, a thick snow cover will result in a smaller change in the snow-ice interface temperature than will a thin snow cover. This small change in the interface temperature will result in a relatively small change in the brine volume at the interface and the resulting complex permittivity, thereby producing a relatively small change in scattering. A thin snow cover produces the opposite effect - a greater change in interface temperature, brine volume, permittivity, and scattering. This work is extended here to illustrate a variation of this effect over landfast first-year sea ice using in situ measurements of physical snow properties and RADARSAT-1 SAR imagery acquired during the winter of 1999 in the central Canadian Archipelago at cold (~ -26°C) and moderately cold (~ -14°C) snow-sea-ice interface temperatures. We utilize in situ data from five validation sites to demonstrate how the change in microwave scattering covaries and is inversely proportional with the change in the magnitude of SWE. These changes are shown to be detectable over both short (2 days) and longer (45 days) time durations. (Au)

G, F, A, E
Atmospheric temperature; Density; Electrical properties; Fast ice; Physical properties; Remote sensing; Salinity; SAR; Snow; Snow water equivalent; Temperature; Temporal variations; Thermal properties; Thermodynamics; Thickness

G0815
Wellington Channel, Nunavut


First-year sea ice spring melt transitions in the Canadian Arctic Archipelago from time-series synthetic aperture radar data, 1992-2002   /   Yackel, J.J.   Barber, D.G.   Papakyriakou, T.N.   Breneman, C.
(Hydrological processes, v. 21, no. 2, 15 Jan. 2007, p. 253-265, ill., maps)
References.
ASTIS record 65915.
Languages: English
Web: doi:10.1002/hyp.6240
Libraries: ACU

This paper synthesizes 10-years' worth of interannual time-series space-borne ERS-1 and RADARSAT-1 synthetic aperture radar (SAR) data collected coincident with daily measurement of snow-covered, land-fast first-year sea ice (FYI) geophysical and surface radiation data collected from the Seasonal Sea Ice Monitoring and Modeling Site, Collaborative-Interdisciplinary Cryospheric Experiment and 1998 North Water Polynya study over the period 1992 to 2002. The objectives are to investigate the seasonal co-relationship of the SAR time-series dataset with selected surface mass (bulk snow thickness) and climate state variables (surface temperature and albedo) measured in situ for the purpose of measuring the interannual variability of sea ice spring melt transitions and validating a time-series SAR methodology for sea ice surface mass and climate state parameter estimation. We begin with a review of the salient processes required for our interpretation of time-series microwave backscatter from land-fast FYI. Our results suggest that time-series SAR data can reliably measure the timing and duration of surface albedo transitions at daily to weekly time-scales and at spatial scales that are on the order of hundreds of metres. Snow thickness on FYI immediately prior to melt onset explains a statistically significant portion of the variability in timing of SAR-detected melt onset to pond onset for SAR time-series that are made up of more than 25 images. Our results also show that the funicular regime of snowmelt, resolved in time-series SAR data at a temporal resolution of approximately 2.5 images per week, is not detectable for snow covers less than 25 cm in thickness. (Au)

G, F, A, E
Albedo; Atmospheric temperature; Cores; Density; Diurnal variations; Energy budgets; Fast ice; Formation; Melting; Puddles; Remote sensing; Salinity; SAR; Satellites; Seasonal variations; Snow; Snow surveys; Snowmelt; Solar radiation; Spatial distribution; Surface temperature; Temperature; Temporal variations; Thermal properties; Thermal regimes; Thermodynamics; Thickness; Weather stations

G09, G0815
Barrow Strait, Nunavut; Cornwallis Island waters, Nunavut; McDougall Sound, Nunavut; North Water Polynya, Baffin Bay; Wellington Channel, Nunavut


Tracing the inputs and fate of marine and terrigenous organic matter in Arctic Ocean sediments : a multivariate analysis of lipid biomarkers   /   Yunker, M.B.   Belicka, L.L.   Harvey, H.R.   Macdonald, R.W.
(The Western Arctic Shelf-Basin Interactions (SBI) project / Edited by J.M. Grebmeier and H.R. Harvey. Deep-sea research. Part II, Topical studies in oceanography, v. 52, no. 24-26, Dec. 2005, p.3478-3508, ill., maps)
References.
ASTIS record 62057.
Languages: English
Web: doi:10.1016/j.dsr2.2005.09.008
Libraries: ACU

An understanding of the carbon cycle within arctic sediments requires discrimination between the terrigenous and marine components of organic carbon, insight into the removal mechanisms for labile carbon during burial and appreciation of shelf-to-basin processes. Using a large data set of multiple molecular organic markers (alkanes, alkanols, sterols, saturated and unsaturated fatty acids, dicarboxylic acids), we apply (1) principal components analysis (PCA) to obtain a robust comparison of biomarker compositions in Arctic Ocean sediments, (2) geometric mean (GM) linear regression of the PCA variables to estimate the relative contributions of labile/marine and stable/terrigenous sources to each biomarker and (3) the slope of the GM regression of each biomarker with TOC to provide a novel measure of the removal rate of each biomarker relative to phytol. The PCA- and TOC-based indices generally increase together: biomarkers with very high TOC-based removal rates such as the saturated and unsaturated n-alkanoic acids generally have a high labile/marine content from PCA, while the sterols have low removal rates, but exhibit a range of labile/marine content values and the n-alkanes and n-alkanols have low values for both. A dominant feature of all PCA models examined is a progressive decrease in the autochthonous/marine biomarkers with each increase in sediment core depth, which points to a universal diagenetic alteration of organic carbon with depth in the cores. The PCA model also displays a shelf to basin trend that is non-diagenetic and implies the ongoing (centuries or more) delivery of long-chain n-alkanes, n-alcohols and n-alkanoic acids in a matrix that is pre-formed and well-preserved within the sediments. Terrigenous biomarker distributions within the PCA model suggest that atmospheric transport of plant waxes in aerosols and the water borne transport of very fine plant macerals likely have significant roles in the export of these vascular plant biomarkers to the basins. Biomarker ratios and profiles of the PCA-based labile/marine content with core depth indicate that the PCA model is more strongly influenced by the biomarker lability than the marine content, while increases in the marine content are largely responsible for the shifts in composition for near-surface core sections. (Au)

B, D, F, A, H, I, J, E
Aerosols; Atmospheric circulation; Biological productivity; Bottom sediments; Carbon; Carbon cycling; Chromatography; Continental shelves; Cores; Fatty acids; Hydrocarbons; Lipids; Mass spectrometry; Measurement; Ocean currents; Ocean floors; Plants (Biology); Primary production (Biology); River discharges; Sediment transport; Sedimentation; Spatial distribution; Suspended solids; Winds

G07, G04, G03, G12
Alaskan Beaufort Sea; Canada Basin, Arctic Ocean; Canadian Beaufort Sea; Chukchi Sea; Fram Basin, Arctic Ocean; Greenland Sea; Makarov Basin, Arctic Ocean; Nansen Basin, Arctic Ocean


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