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Sample records for canadian arctic gas

  1. Brewer spectrophotometer measurements in the Canadian Arctic

    NASA Technical Reports Server (NTRS)

    Kerr, J. B.; Evans, W. F. J.

    1988-01-01

    In the winters of 1987 and 1988 measurements were conducted with the Brewer Spectrophotometer at Alert (82.5 N) and Resolute (74.5 N). The measurements were conducted as part of our Canadian Program to search for an Arctic Ozone Hole (CANOZE). Ozone measurements were conducted in the months of December, January and February using the moon as a light source. The total ozone measurements will be compared with ozonesonde profiles, from ECC sondes, flown once per week from Alert and Resolute. A modified Brewer Spectrophotometer was used in a special study to search for chlorine dioxide at Alert in March 1987. Ground based observations at Saskatoon in February and at Alert in March 1987 failed to detect any measureable chlorine dioxide. Interference from another absorbing gas, which we speculate may be nitrous acid, prevented the measurements at the low levels of chlorine dioxide detected in the Southern Hemisphere by Solomon et al.

  2. Science Traverses in the Canadian High Arctic

    NASA Technical Reports Server (NTRS)

    Williamson, Marie-Claude

    2012-01-01

    The presentation is divided into three parts. Part I is an overview of early expeditions to the High Arctic, and their political consequences at the time. The focus then shifts to the Geological Survey of Canada s mapping program in the North (Operation Franklin), and to the Polar Continental Shelf Project (PCSP), a unique organization that resides within the Government of Canada s Department of Natural Resources, and supports mapping projects and science investigations. PCSP is highlighted throughout the presentation so a description of mandate, budgets, and support infrastructure is warranted. In Part II, the presenter describes the planning required in advance of scientific deployments carried out in the Canadian High Arctic from the perspective of government and university investigators. Field operations and challenges encountered while leading arctic field teams in fly camps are also described in this part of the presentation, with particular emphasis on the 2008 field season. Part III is a summary of preliminary results obtained from a Polar Survey questionnaire sent out to members of the Arctic research community in anticipation of the workshop. The last part of the talk is an update on the analog program at the Canadian Space Agency, specifically, the Canadian Analog Research Network (CARN) and current activities related to Analog missions, 2009-2010.

  3. Canadian system extends Arctic drilling season

    SciTech Connect

    Park, D.A.

    1984-06-18

    Faced with the possibility of insufficient drilling equipment to meet accelerated exploration programs in the Canadian Beaufort Sea, Gulf Canada Resources Inc. of Calgary, Alta., undertook in 1981 to build a major new drilling system that would be capable of operating in Arctic water depths ranging from 50 to 180 ft. The company decided to design the system to extend the drilling season beyond that achieved with modified conventional drillships. The new system is operated by BeauDril Ltd., the Arctic offshore drilling subsidiary of Gulf Canada Resources. It consists of a mobile, bottomfounded, shallow-water drilling unit named Molikpaq; a conically shaped, deeper-water unit called Kulluk; two ice-breakers and two icebreaking supply vessels (all Ice Class IV); a large operations base at Tuktoyaktuk; and a floating marine base. With the exception of Molikpaq (delivered mid-April this year), the system became operational in the summer of 1983. In addition to discussing engineering and construction challenges resulting from the extension of the drilling season to mid-December, this article describes the mobilization of Kulluk and her supporting fleet to the Beaufort Sea, highlighting vessel positioning, and drilling operations at the first well locations.

  4. Lidar Atmospheric Observatory in the Canadian Arctic

    NASA Technical Reports Server (NTRS)

    Ulitsky, Arkady; Wang, Tin-Yu; Flood, Martin; Smith, Brent

    1992-01-01

    During the last decade there have been growing concerns about a broad variety of atmospheric properties. Among these, a depletion of the stratospheric ozone layer has attracted considerable attention from the general public, politicians and scientists due to its vital impact for the entire global biosphere. One of the major warning signs was the discovery of the 'ozone hole' in the Antarctic region where the concentration of the ozone in the stratosphere was significantly reduced. At present the stratospheric ozone layer in this region is being continuously monitored by groups of scientists from around the world and numerous observations of the ozone layer on the global scale have clearly demonstrated the process of ozone depletion. Recent observations by NASA have shown significant depletion in the Arctic region. This paper provides an initial description of two lidars that are planned to be installed in a new observatory for atmospheric studies in the Canadian Arctic. This observatory is being constructed under the supervision of the Atmospheric Environment Services (AES) of Canada as a part of Green Plan - an initiative of the Federal Government of Canada. The station is located at Eureka on Ellesmere Island at a latitude of 80 degrees N and a longitude of 86 degrees W.

  5. Remagnetization and Cementation of Unconsolidated Sediments in the Mallik 5L-38 Well (Canadian Arctic) by Solute Exclusion During Gas Hydrate Formation

    NASA Astrophysics Data System (ADS)

    Hamilton, T. S.; Enkin, R. J.; Esteban, L.

    2007-05-01

    Bulk magnetic properties provide a sensitive measure of sedimentary diagenesis related to the stability and growth of gas hydrates. The deposit at Mallik (Mackenzie Delta, Canadian Arctic) occurs in unconsolidated Tertiary sands, but is absent in interstratified silt layers. A detailed sampling of the JAPEX/JNOC/GSC Mallik 5L-38 core tested the use of magnetic properties for detecting diagenetic changes related to the hydrate. Petrographic studies reveal that the sands are well sorted and clean, with quartz > chert >> muscovite and little fines content. Excepting a few rare bands of indurated dolomite in the midst of the gas hydrate zone, there is little or no cementation in the sands. Detrital magnetite is the dominant magnetic mineral, comprising up to a few percent of the sand grain population. In contrast, the muddier layers have a somewhat different detrital grain composition, richer in lithic (sedimentary and metamorphic) grains, feldspar, and clays. They are extensively diagenetically altered (to as much as 30- 40%) and cemented with carbonates, clays, chlorite and the iron sulphide greigite (the dominant magnetic mineral). The greigite is recognized by its isotropic creamy-white reflectance, cubic to prismatic habit, and characteristic tarnish to faintly bluish bireflectant mackinawite. Habits range from disseminated cubes and colliform masses to inflationary massive sulphide veins and clots. Rare detrital grains of magnetite were observed among the silt grains, but never in a reaction relationship or overgrown. Instead the greigite has nucleated separately, in tensional fractures and granular masses up to 4 mm across. In this particular sediment sequence, being so quartz and chert rich, there is insufficient local source for the introduced cements (calcite, dolomite, greigite, clays, jarosite), so ions must have been introduced by fluid flow. Magnetic studies reveal a bi-modal character related to the lithology (sands versus silts) and their magnetic

  6. Television Effects on Canadian Arctic High School Students.

    ERIC Educational Resources Information Center

    Coldevin, Gary O.

    The purpose of this study was to contrast and compare television effects across three types of students at a high school in the Canadian Arctic--Euro-Canadian students, Inuit students resident in Frobisher Bay, and Inuit students from isolated settlements. Television had recently been introduced to the area by means of a satellite re-broadcast…

  7. Television Effects on Canadian Arctic High School Students.

    ERIC Educational Resources Information Center

    Coldevin, Gary O.

    The purpose of this study was to contrast and compare television effects across three types of students at a high school in the Canadian Arctic--Euro-Canadian students, Inuit students resident in Frobisher Bay, and Inuit students from isolated settlements. Television had recently been introduced to the area by means of a satellite re-broadcast…

  8. Transport Pathways of Pollution Plumes into the Canadian Arctic during RACEPAC and NETCARE 2014

    NASA Astrophysics Data System (ADS)

    Hoor, P. M.; Bozem, H.; Koellner, F.; Schneider, J.; Schulz, C.; Burkart, J.; Willis, M. D.; Herber, A. B.; Borrmann, S.; Wendisch, M.; Ehrlich, A.; Leaitch, W. R.; Abbatt, J.

    2014-12-01

    We present trace gas measurements in the Arctic during RACEPAC and NETCARE 2014. The measurements were performed in May and July 2014 out of Inuvik and Resolute Bay with the POLAR 6 DC-3 aircraft of Alfred Wegener Institute (AWI) and focused on cloud processes in the Canadian Arctic as well as transport processes of pollution. CO and CO2 measurements indicate that long range transport from various sources affected the arctic lower troposphere during spring /summer 2014. Whereas the high latitudes were relatively unaffected by pollution plumes from lower latitudes, the more southern parts of the arctic regions were strongly perturbed by pollution from various sources. These events are likely connected to biomass burning. We also performed measurements of local emissions from shipping, to investigate their potential to penetrate the arctic boundary layer and affect the arctic free troposphere thereby becoming part of the large scale flow.

  9. Helicobacter pylori infection in Canadian and related Arctic Aboriginal populations

    PubMed Central

    Goodman, Karen J; Jacobson, Kevan; van Zanten, Sander Veldhuyzen

    2008-01-01

    In 2006, the Canadian Helicobacter Study Group identified Aboriginal communities among Canadian population groups most at risk of Helicobacter pylori-associated disease. The objective of this systematic review was to summarize what is known about the H pylori-associated disease burden in Canadian and related Arctic Aboriginal populations to identify gaps in knowledge. Six health literature databases were systematically searched to identify reports on H pylori prevalence in Canadian population groups, or any topic related to H pylori in Canadian Aboriginals, Alaska Natives or Aboriginals of other Arctic regions. Identified reports were organized by subtopic and summarized in narrative form. Key data from studies of H pylori prevalence in defined populations were summarized in tabular form. A few Arctic Aboriginal communities were represented in the literature: two Canadian Inuit; one Canadian First Nation; two Greenland Inuit; one Russian Chutkotka Native; and several Alaska Native studies. These studies uniformly showed elevated H pylori prevalence; a few studies also showed elevated occurrence of H pylori-related diseases and high rates of treatment failure. Based on the evidence, it would be warranted for clinicians to relax the criteria for investigating H pylori and related diseases in patients from Arctic Aboriginal communities, and to pursue post-therapy confirmation of eradication. Additional community-based research is needed to develop public health policies for reducing H pylori-associated health risks in such communities. PMID:18354758

  10. Helicobacter pylori infection in Canadian and related Arctic Aboriginal populations.

    PubMed

    Goodman, K J; Jacobson, K; Veldhuyzen van Zanten, S

    2008-03-01

    In 2006, the Canadian Helicobacter Study Group identified Aboriginal communities among Canadian population groups most at risk of Helicobacter pylori-associated disease. The objective of this systematic review was to summarize what is known about the H pylori-associated disease burden in Canadian and related Arctic Aboriginal populations to identify gaps in knowledge. Six health literature databases were systematically searched to identify reports on H pylori prevalence in Canadian population groups, or any topic related to H pylori in Canadian Aboriginals, Alaska Natives or Aboriginals of other Arctic regions. Identified reports were organized by subtopic and summarized in narrative form. Key data from studies of H pylori prevalence in defined populations were summarized in tabular form. A few Arctic Aboriginal communities were represented in the literature: two Canadian Inuit; one Canadian First Nation; two Greenland Inuit; one Russian Chutkotka Native; and several Alaska Native studies. These studies uniformly showed elevated H pylori prevalence; a few studies also showed elevated occurrence of H pylori-related diseases and high rates of treatment failure. Based on the evidence, it would be warranted for clinicians to relax the criteria for investigating H pylori and related diseases in patients from Arctic Aboriginal communities, and to pursue post-therapy confirmation of eradication. Additional community-based research is needed to develop public health policies for reducing H pylori-associated health risks in such communities.

  11. Silurian pinnacle reefs of the Canadian Arctic

    SciTech Connect

    De Freitas, T.A.; Dixon, O.A. ); Mayr, U. )

    1993-04-01

    Pinnacle reefs are commonly an attractive target for oil exploration because they are usually porous carbonate bodies entombed in impervious, deep-water shales that provide both the source and the seal for hydrocarbons. Silurian pinnacle reefs, the first described in the Canadian Arctic Archipelago, are exposed on Ellesmere and Devon Islands. Two main reef trends occur, one of early middle Llandovery to middle Ludlow age and a second of middle Ludlow to Late Silurian or Early Devonian age. Reefs of both phases contain lime mudstone cores: some are stromatactoid-rich and others consist predominantly of microbialite-rich lime mudstone or microbial boundstone. Facies sequences of both reef phases show evidence of upward-shallowing overall, but, in the older reefs, isochronous capping facies are dominated either by coral-mirian or by stromatoporoid boundstone and floatstone. This difference perhaps reflects variation in wave stress and apparent ability of a few corals,thickly encrusted by or associated with microbial boundstone and skeletal algae, to withstand greater wave energy than a stromatoporoid-coral-rich reef community. These reefs constitute one of the bright prospects of hydrocarbon exploration in rocks of the Franklinian succession. 43 refs., 9 figs.

  12. Potential geologic hazards of Arctic gas hydrates

    SciTech Connect

    Collett, T.S. )

    1990-05-01

    Sediments of the Arctic region may contain enormous quantities of natural gas in the form of gas hydrates, which are crystalline substances composed of water and mostly methane gas. These ice-like substances are generally found in two distinct environments: (1) offshore in sediments of outer continental margins and (2) nearshore and onshore in areas associated with the occurrence of permafrost. Recently, US, Canadian, and Soviet researchers have described numerous drilling and production problems attributed to the presence of gas hydrates, including uncontrolled gas releases during drilling, collapsed casings, and gas leakage to the surface. When the drill bit penetrates a gas hydrate, the drilling mud, unless cooled significantly by the operator, will become highly gasified as the hydrate decomposes. The hydrate adjacent to the well bore will continue to decompose and gasify the drilling mud as long as drilling and/or production introduces heat into the hydrate-bearing interval. The production of hot fluids from depth through the permafrost and gas hydrate-bearing intervals adversely raises formation temperatures, thus decomposing the gas hydrates. If the disassociated, free gas is trapped behind the casing, reservoir pressures may substantially increase and cause the casing to collapse. In several wells in northern Alaska, the disassociated free gas has leaked to the surface outside the conductor casing. An additional drilling hazard associated with gas hydrates results from the sealing attributes of hydrates, which may trap large volumes of over pressured free gas at shallow depths. Even though documented problems attributed to the presence of gas hydrates have been relatively few, it is likely that as exploration and development activity moves farther offshore into deeper water (>300 m) and to higher latitudes in the Arctic, the frequency of gas hydrate-related problems will increase.

  13. Gut Microbiome of the Canadian Arctic Inuit

    PubMed Central

    Tromas, Nicolas; Amyot, Marc

    2017-01-01

    ABSTRACT Diet is a major determinant of community composition in the human gut microbiome, and “traditional” diets have been associated with distinct and highly diverse communities, compared to Western diets. However, most traditional diets studied have been those of agrarians and hunter-gatherers consuming fiber-rich diets. In contrast, the Inuit of the Canadian Arctic have been consuming a traditional diet low in carbohydrates and rich in animal fats and protein for thousands of years. We hypothesized that the Inuit diet and lifestyle would be associated with a distinct microbiome. We used deep sequencing of the 16S rRNA gene to compare the gut microbiomes of Montrealers with a Western diet to those of the Inuit consuming a range of traditional and Western diets. At the overall microbial community level, the gut microbiomes of Montrealers and Inuit were indistinguishable and contained similar levels of microbial diversity. However, we observed significant differences in the relative abundances of certain microbial taxa down to the subgenus level using oligotyping. For example, Prevotella spp., which have been previously associated with high-fiber diets, were enriched in Montrealers and among the Inuit consuming a Western diet. The gut microbiomes of Inuit consuming a traditional diet also had significantly less genetic diversity within the Prevotella genus, suggesting that a low-fiber diet might not only select against Prevotella but also reduce its diversity. Other microbes, such as Akkermansia, were associated with geography as well as diet, suggesting limited dispersal to the Arctic. Our report provides a snapshot of the Inuit microbiome as Western-like in overall community structure but distinct in the relative abundances and diversity of certain genera and strains. IMPORTANCE Non-Western populations have been shown to have distinct gut microbial communities shaped by traditional diets. The hitherto-uncharacterized microbiome of the Inuit may help us to

  14. Mercury in the Canadian Arctic terrestrial environment: an update.

    PubMed

    Gamberg, Mary; Chételat, John; Poulain, Alexandre J; Zdanowicz, Christian; Zheng, Jiancheng

    2015-03-15

    Contaminants in the Canadian Arctic have been studied over the last twenty years under the guidance of the Northern Contaminants Program. This paper provides the current state of knowledge on mercury (Hg) in the Canadian Arctic terrestrial environment. Snow, ice, and soils on land are key reservoirs for atmospheric deposition and can become sources of Hg through the melting of terrestrial ice and snow and via soil erosion. In the Canadian Arctic, new data have been collected for snow and ice that provide more information on the net accumulation and storage of Hg in the cryosphere. Concentrations of total Hg (THg) in terrestrial snow are highly variable but on average, relatively low (<5 ng L(-1)), and methylmercury (MeHg) levels in terrestrial snow are also generally low (<0.1 ng L(-1)). On average, THg concentrations in snow on Canadian Arctic glaciers are much lower than those reported on terrestrial lowlands or sea ice. Hg in snow may be affected by photochemical exchanges with the atmosphere mediated by marine aerosols and halogens, and by post-depositional redistribution within the snow pack. Regional accumulation rates of THg in Canadian Arctic glaciers varied little during the past century but show evidence of an increasing north-to-south gradient. Temporal trends of THg in glacier cores indicate an abrupt increase in the early 1990 s, possibly due to volcanic emissions, followed by more stable, but relatively elevated levels. Little information is available on Hg concentrations and processes in Arctic soils. Terrestrial Arctic wildlife typically have low levels of THg (<5 μg g(-1) dry weight) in their tissues, although caribou (Rangifer tarandus) can have higher Hg because they consume large amounts of lichen. THg concentrations in the Yukon's Porcupine caribou herd vary among years but there has been no significant increase or decrease over the last two decades. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Safeguarding Canadian Arctic Sovereignty Against Conventional Threats

    DTIC Science & Technology

    2009-06-01

    Charron acknowledge that Canada is lacking military capabilities to protect its sovereignty in the Arctic, but argue that the favorable course of...Associations Institute, 2007), 119-120. 35 64 Andrea Charron , ―The True North : Stronger and Freer with help,‖ Defence Requirements for Canada’s...Would Rule: Climate Change in the Arctic and its Implications for U.S. National Security.‖ 204-222. Charron , Andrea. ―The Northwest Passage Shipping

  16. Variability of phytoplankton light absorption in Canadian Arctic seas

    NASA Astrophysics Data System (ADS)

    Brunelle, Corinne B.; Larouche, Pierre; Gosselin, Michel

    Phytoplankton light absorption spectra (aϕ(λ)) were measured in the Canadian Arctic (i.e., the Amundsen Gulf, Canadian Arctic Archipelago, northern Baffin Bay and the Hudson Bay system) to improve algorithms used in remote-sensing models of primary production. The absorption by algae, dominated by picophytoplankton (<5 μm), was not the major light absorption factor in the four provinces; the colored dissolved organic matter (CDOM) contributed up to 70% of total light absorption. During the fall, the low total chlorophyll a-specific aϕ*(443) (aϕ(443)/TChl a) coefficients of the Canadian High Arctic were associated with photoacclimation processes (i.e., the package effect) occurring in light-limited environments. Low light availability and high proportion of CDOM (absorbing strongly the ultraviolet) seem to allow the growth of phytoplankton with accessory pigments absorbing light at longer wavelengths. The ratio of photoprotective and photosynthetic carotenoids (PPC:PSC) was inversely proportional with the salinity and the cell size, and mostly decreases throughout the Canadian High Arctic during fall. In return, the highest TChl a-specific phytoplankton light absorption coefficients at the blue peak (aϕ*(443)) were observed in the Hudson Bay system from September to October (i.e., fall) as well as in the Amundsen Gulf from May to July (i.e., spring/summer). These results will ultimately allow the accurate monitoring of phytoplankton biomass and productivity evolution that is likely to take place as a result of the fast-changing Arctic environment.

  17. Early Carboniferous (Visean) lacustrine oil shale in Canadian Arctic archipelago

    SciTech Connect

    Davies, G.R.; Nassichuk, W.W.

    1988-01-01

    The Lower Carboniferous (Visean) Emma Fiord Formation in the Canadian Arctic Archipelago is an oil shale of lacustrine origin composed of black carbonaceous shale, siltstone, and marlstone with interbedded sandstone, conglomerate, and oolitic and algal limestones. At Kleybolte Peninsula on Ellesmere Island, the Emma Fiord Formation was deposited on the tectonically active northwestern rim of the Sverdrup basin; it is now thermally overmature and well beyond the dry gas zone of organic maturation (vitrinite reflectance approx. = 5.0). In contrast, the Emma Fiord sequence on Grinnell Peninsula, Devon Island, near the southern edge of the Sverdrup basin, is immature to marginally mature (vitrinite reflectance = 0.26-0.44) and is composed predominantly of liptinite-rich oil shale. These kerogen-rich rocks contain a high volume of microcrystalline calcite and compositionally are marlstones. The Emma Fiord oil shales were deposited in lakes formed immediately prior to or possibly synchronous with the initiation of rifting in the Sverdrup basin. Syntectonic red-bed conglomerates derived from uplifted horst blocks directly overlie the Emma Fiord rocks. A few beds of conglomerate and sandstone in the upper part of the Emma Fiord Formation possibly record the onset of faulting. The formation closely resembles contemporaneous sequences in northern Alaska, Yukon Territory, Greenland, and Spitsbergen. Clearly, similar tectonic and paleoclimatic factors influenced sedimentation over this area in the Early Carboniferous, with the Sverdrup basin locations lying within 10/sup 0/-15/sup 0/ of the paleoequator. 11 figures, 2 tables.

  18. Persistent maritime traffic monitoring for the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Ulmke, M.; Battistello, G.; Biermann, J.; Mohrdieck, C.; Pelot, R.; Koch, W.

    2017-05-01

    This paper presents results of the Canadian-German research project PASSAGES (Protection and Advanced Surveillance System for the Arctic: Green, Efficient, Secure)1 on an advanced surveillance system for safety and security of maritime operations in Arctic areas. The motivation for a surveillance system of the Northwest Passage is the projected growth of maritime traffic along Arctic sea routes and the need for securing Canada's sovereignty by controlling its arctic waters as well as for protecting the safety of international shipping and the intactness of the arctic marine environment. To ensure border security and to detect and prevent illegal activities it is necessary to develop a system for surveillance and reconnaissance that brings together all related means, assets, organizations, processes and structures to build one homogeneous and integrated system. The harsh arctic conditions require a new surveillance concept that fuses heterogeneous sensor data, contextual information, and available pre-processed surveillance data and combines all components to efficiently extract and provide the maximum available amount of information. The fusion of all these heterogeneous data and information will provide improved and comprehensive situation awareness for risk assessment and decision support of different stakeholder groups as governmental authorities, commercial users and Northern communities.

  19. Vegetation greening in the Canadian Arctic related to decadal warming.

    PubMed

    Jia, Gensuo J; Epstein, Howard E; Walker, Donald A

    2009-12-01

    This study is presented within the context that climate warming and sea-ice decline has been occurring throughout much of the Arctic over the past several decades, and that terrestrial ecosystems at high latitudes are sensitive to the resultant alterations in surface temperatures. Results are from analyzing interannual satellite records of vegetation greenness across a bioclimate gradient of the Canadian Arctic over the period of 1982-2006. Here, we combine multi-scale sub-pixel analysis and remote sensing time-series analysis to investigate recent decadal changes in vegetation greenness along spatial gradients of summer temperature and vegetation. Linear autoregression temporal analysis of vegetation greenness was performed with relatively "pure" vegetation pixels of Advanced Very High Resolution Radiometer (AVHRR) data, spanning Low Arctic, High Arctic and polar desert ecosystems. Vegetation greenness generally increased over tundra ecosystems in the past two decades. Peak annual greenness increased 0.49-0.79%/yr over the High Arctic where prostrate dwarf shrubs, forbs, mosses and lichens dominate and 0.46-0.67%/yr over the Low Arctic where erect dwarf shrubs and graminoids dominate. However, magnitudes of vegetation greenness differ with length of time series and periods considered, indicating a nonlinear response of terrestrial ecosystems to climate change. The decadal increases of greenness reflect increasing vegetation production during the peak of the growing season, and were likely driven by the recent warming.

  20. Environmental contaminants and human health in the Canadian Arctic.

    PubMed

    Donaldson, S G; Van Oostdam, J; Tikhonov, C; Feeley, M; Armstrong, B; Ayotte, P; Boucher, O; Bowers, W; Chan, L; Dallaire, F; Dallaire, R; Dewailly, E; Edwards, J; Egeland, G M; Fontaine, J; Furgal, C; Leech, T; Loring, E; Muckle, G; Nancarrow, T; Pereg, D; Plusquellec, P; Potyrala, M; Receveur, O; Shearer, R G

    2010-10-15

    The third Canadian Arctic Human Health Assessment conducted under the Canadian Northern Contaminants Program (NCP), in association with the circumpolar Arctic Monitoring and Assessment Programme (AMAP), addresses concerns about possible adverse health effects in individuals exposed to environmental contaminants through a diet containing country foods. The objectives here are to: 1) provide data on changes in human contaminant concentrations and exposure among Canadian Arctic peoples; 2) identify new contaminants of concern; 3) discuss possible health effects; 4) outline risk communication about contaminants in country food; and 5) identify knowledge gaps for future contaminant research and monitoring. The nutritional and cultural benefits of country foods are substantial; however, some dietary studies suggest declines in the amount of country foods being consumed. Significant declines were found for most contaminants in maternal blood over the last 10 years within all three Arctic regions studied. Inuit continue to have the highest levels of almost all persistent organic pollutants (POPs) and metals among the ethnic groups studied. A greater proportion of people in the East exceed Health Canada's guidelines for PCBs and mercury, although the proportion of mothers exceeding these guidelines has decreased since the previous assessment. Further monitoring and research are required to assess trends and health effects of emerging contaminants. Infant development studies have shown possible subtle effects of prenatal exposure to heavy metals and some POPs on immune system function and neurodevelopment. New data suggest important beneficial effects on brain development for Inuit infants from some country food nutrients. The most successful risk communication processes balance the risks and benefits of a diet of country food through input from a variety of regional experts and the community, to incorporate the many socio-cultural and economic factors to arrive at a risk

  1. Literacy Lives Here: Using Video and Dialogue to Promote and Celebrate Adult and Literacy Education in the Canadian Western Arctic

    ERIC Educational Resources Information Center

    Robinson, Suzanne

    2009-01-01

    The Canadian North, one of the most isolated parts of the world, has been subject to increased scrutiny as a source of untapped oil and gas, a global warming harbinger and casualty, and a center of international sovereignty debate. What is often forgotten is that in addition to a resource bed and a border, the Arctic is first a homeland--a…

  2. Literacy Lives Here: Using Video and Dialogue to Promote and Celebrate Adult and Literacy Education in the Canadian Western Arctic

    ERIC Educational Resources Information Center

    Robinson, Suzanne

    2009-01-01

    The Canadian North, one of the most isolated parts of the world, has been subject to increased scrutiny as a source of untapped oil and gas, a global warming harbinger and casualty, and a center of international sovereignty debate. What is often forgotten is that in addition to a resource bed and a border, the Arctic is first a homeland--a…

  3. The Arctic--A Global Hot Spot: Resources for Teaching the Geography of the Contemporary Canadian Arctic

    ERIC Educational Resources Information Center

    Arntzen, Betsy; Sotherden, Amy

    2011-01-01

    Canadian geography is a fascinating topic, particularly the Canadian North. The North is central to Canadian identity as can be seen by the choice of the far north "inukshuk" standing stones as the emblem for the 2010 Winter Olympics held in Vancouver, southern British Columbia. Canada's Arctic is receiving increasing attention by media,…

  4. The Arctic--A Global Hot Spot: Resources for Teaching the Geography of the Contemporary Canadian Arctic

    ERIC Educational Resources Information Center

    Arntzen, Betsy; Sotherden, Amy

    2011-01-01

    Canadian geography is a fascinating topic, particularly the Canadian North. The North is central to Canadian identity as can be seen by the choice of the far north "inukshuk" standing stones as the emblem for the 2010 Winter Olympics held in Vancouver, southern British Columbia. Canada's Arctic is receiving increasing attention by media,…

  5. Obstetric care in the central Canadian Arctic.

    PubMed

    Baskett, T F

    1978-10-07

    All pregnancies that occurred during 1971-5 among 4000 Canadian Eskimos living in isolated settlements in a district of the North-west Territories were reviewed. Obstetric care was provided in settlement nursing stations, at a base hospital manned by general practitioners, and at a teaching hospital in Winnipeg. Of the 622 infants delivered in 1971-5 218 were delivered in nursing stations by midwives, 338 in the base hospital, and 54 in the teaching hospital. Caesarean sections were performed in 10 cases, and the perinatal mortality was 25.7 per 1000 births. Though it is hard to defend patients delivering their babies in remote areas with no medical help, the results seemed to be acceptable. The credit for this goes to experienced midwives, a liberal evacuation policy, close co-operation from general practitioners, and the specialist visiting and consulting service.

  6. Arctic Oil and Natural Gas Potential

    EIA Publications

    2009-01-01

    This paper examines the discovered and undiscovered Arctic oil and natural gas resource base with respect to their location and concentration. The paper also discusses the cost and impediments to developing Arctic oil and natural gas resources, including those issues associated with environmental habitats and political boundaries.

  7. Modern pollen data from the Canadian Arctic, 1972-1973

    NASA Astrophysics Data System (ADS)

    Nichols, Harvey; Stolze, Susann

    2017-05-01

    This data descriptor reports results of a 1972-73 baseline study of modern pollen deposition in the Canadian Arctic to originally aid interpretation of Holocene pollen diagrams from that region, especially focussed on the arctic tree-line. The data set is geographically unique due to its extent, and allows the assessment of the effects of modern climate change on northern ecosystems, including fluctuations of the a arctic tree-line. Repeated sampling was conducted along an interior transect at 29 sites from the Boreal Forest to the High Arctic, with five additional coastal sites covering a total distance of 3,200 km. Static pollen samplers captured both local pollen and long-distance pollen wind-blown from the Boreal Forest. Moss and lichen polsters provided multi-year pollen fallout to assess the effectiveness of the static pollen samplers. The local vegetation was recorded at each site. This descriptor provides information on data archived at the World Data Center PANGAEA, which includes spreadsheets detailing site and sample information as well as raw and processed pollen data obtained on over 500 samples.

  8. Modern pollen data from the Canadian Arctic, 1972–1973

    PubMed Central

    Nichols, Harvey; Stolze, Susann

    2017-01-01

    This data descriptor reports results of a 1972–73 baseline study of modern pollen deposition in the Canadian Arctic to originally aid interpretation of Holocene pollen diagrams from that region, especially focussed on the arctic tree-line. The data set is geographically unique due to its extent, and allows the assessment of the effects of modern climate change on northern ecosystems, including fluctuations of the a arctic tree-line. Repeated sampling was conducted along an interior transect at 29 sites from the Boreal Forest to the High Arctic, with five additional coastal sites covering a total distance of 3,200 km. Static pollen samplers captured both local pollen and long-distance pollen wind-blown from the Boreal Forest. Moss and lichen polsters provided multi-year pollen fallout to assess the effectiveness of the static pollen samplers. The local vegetation was recorded at each site. This descriptor provides information on data archived at the World Data Center PANGAEA, which includes spreadsheets detailing site and sample information as well as raw and processed pollen data obtained on over 500 samples. PMID:28509898

  9. Modern pollen data from the Canadian Arctic, 1972-1973.

    PubMed

    Nichols, Harvey; Stolze, Susann

    2017-05-16

    This data descriptor reports results of a 1972-73 baseline study of modern pollen deposition in the Canadian Arctic to originally aid interpretation of Holocene pollen diagrams from that region, especially focussed on the arctic tree-line. The data set is geographically unique due to its extent, and allows the assessment of the effects of modern climate change on northern ecosystems, including fluctuations of the a arctic tree-line. Repeated sampling was conducted along an interior transect at 29 sites from the Boreal Forest to the High Arctic, with five additional coastal sites covering a total distance of 3,200 km. Static pollen samplers captured both local pollen and long-distance pollen wind-blown from the Boreal Forest. Moss and lichen polsters provided multi-year pollen fallout to assess the effectiveness of the static pollen samplers. The local vegetation was recorded at each site. This descriptor provides information on data archived at the World Data Center PANGAEA, which includes spreadsheets detailing site and sample information as well as raw and processed pollen data obtained on over 500 samples.

  10. Geochemical heterogeneity of rivers draining the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Alkire, M. B.; Jacobson, A. D.; Lehn, G. O.; Macdonald, R. W.; Rossi, M. W.

    2016-12-01

    River discharge contributes 38% of the annual freshwater input to the Arctic Ocean. While numerous studies have documented variations in the water discharge, sediment load, and geochemistry of the largest Arctic rivers (Ob, Yenisey, Lena, Kolyma, Mackenzie, and Yukon Rivers), there are hundreds of smaller rivers that remain ungauged and/or rarely sampled. Collectively, rivers draining the Canadian Arctic Archipelago and immediately adjacent regions (CAA) contribute 200-250 km3 yr-1 of freshwater to the Arctic and subarctic seas. This undocumented freshwater input complicates attempts to separate contributions from North American (i.e., Mackenzie River) and Siberian river discharges to the freshwater export through Davis Strait. In this study, we collected water samples from CAA rivers and their estuaries in order to characterize their geochemical composition and better constrain the collective impact of CAA rivers on the Arctic freshwater budget. Several variables (e.g., δ18O, Ba, nutrients, total alkalinity, DOC, major ions, and 87Sr/86Sr) were analyzed for water samples taken from ten different rivers extending across the CAA during spring (June-July) 2014 and summer (July-August) 2015. Major ion abundances mostly reflect mixing between carbonic acid weathering reactions and atmospheric deposition, with minimal contributions from sulfide oxidation. In general, rivers displaying higher solute concentrations drain the western and/or northern CAA, whereas those with lower concentrations drain the eastern and/or southern CAA. Geochemical signatures largely correlate with differences in bedrock geology, with the western and/or northern CAA comprising carbonate bedrock and the eastern and/or southern CAA comprising silicate bedrock. Combining these observations with GIS analyses, we assess the contributions of all watersheds in the CAA >100 km2 to develop a regional-scale assessment of solute and water delivery to CAA boundary currents.

  11. Estimates of Canadian Arctic Archipelago runoff from observed hydrometric data

    NASA Astrophysics Data System (ADS)

    Spence, Christopher; Burke, Amanda

    2008-12-01

    SummarySmall basin studies in the remote Canadian Arctic Archipelago have revealed the general nature of runoff processes and the annual rhythms and magnitude of streamflow in the region, but widespread monitoring of hydrological cycle components is absent. The result is that an understanding of large scale freshwater fluxes from the Arctic Archipelago does not exist. Such understanding is important for sound domestic water management decisions and international obligations to quantify Canada's freshwater supply to the oceans. The study summarized by this paper, initiated under the auspices of the International Polar Year, extrapolated observed streamflow attributes across the Arctic Archipelago using statistical regionalization tools. The paucity of hydrometric data necessitated the construction of a dataset, which was limited to the period from 1972 to 1994. Reliable estimates of mean May-October freshwater flux were possible from ˜70% of the Archipelago and these total ˜190 km 3. Maximum daily runoff can be up to 13% of the total annual flux from some catchments. Flows were highest from southern Baffin Island, decreasing westward. The scarcity of data compelled an error analysis that showed average confidence intervals around constructed and regionalized data of ±123% and ±63%, respectively. Dataset construction errors were inversely related to basin area. There was no spatial pattern to the dataset construction errors, but regionalization error tended to be higher in the west. It will be argued that our community has little to no idea of the current freshwater flux from the Arctic Archipelago, or if it is changing. Much work is needed to improve these estimates, including establishing a sustainable, effective and efficient monitoring and research program of high arctic freshwater systems that can build upon the legacy of the International Polar Year.

  12. New vascular plant records for the Canadian Arctic Archipelago

    PubMed Central

    Gillespie, Lynn J.; Saarela, Jeffery M.; Sokoloff, Paul C.; Bull, Roger D.

    2015-01-01

    Abstract The Canadian Arctic Archipelago is a vast region of approximately 1,420,000 km2, with a flora characterized by low species diversity, low endemicity, and little influence by alien species. New records of vascular plant species are documented here based on recent fieldwork on Victoria and Baffin Islands; additional records based on recent literature sources are mentioned. This paper serves as an update to the 2007 publication Flora of the Canadian Arctic Archipelago, and brings the total number of vascular plants for the region to 375 species and infraspecific taxa, an increase of 7.7%. Three families (Amaranthaceae, Juncaginaceae, Pteridaceae) and seven genera (Cherleria L., Cryptogramma R. Br., Platanthera Rich., Sabulina Rchb., Suaeda Forssk. ex J.F. Gmel., Triglochin L., Utricularia L.) are added to the flora, and one genus is deleted (Minuartia L.). Five species are first records for Nunavut (Arenaria longipedunculata Hultén, Cryptogramma stelleri (S.G. Gmel.) Prantl, Puccinellia banksiensis Consaul, Saxifraga eschscholtzii Sternb., Utricularia ochroleuca R.W. Hartm.) PMID:26311505

  13. New vascular plant records for the Canadian Arctic Archipelago.

    PubMed

    Gillespie, Lynn J; Saarela, Jeffery M; Sokoloff, Paul C; Bull, Roger D

    2015-01-01

    The Canadian Arctic Archipelago is a vast region of approximately 1,420,000 km(2), with a flora characterized by low species diversity, low endemicity, and little influence by alien species. New records of vascular plant species are documented here based on recent fieldwork on Victoria and Baffin Islands; additional records based on recent literature sources are mentioned. This paper serves as an update to the 2007 publication Flora of the Canadian Arctic Archipelago, and brings the total number of vascular plants for the region to 375 species and infraspecific taxa, an increase of 7.7%. Three families (Amaranthaceae, Juncaginaceae, Pteridaceae) and seven genera (Cherleria L., Cryptogramma R. Br., Platanthera Rich., Sabulina Rchb., Suaeda Forssk. ex J.F. Gmel., Triglochin L., Utricularia L.) are added to the flora, and one genus is deleted (Minuartia L.). Five species are first records for Nunavut (Arenarialongipedunculata Hultén, Cryptogrammastelleri (S.G. Gmel.) Prantl, Puccinelliabanksiensis Consaul, Saxifragaeschscholtzii Sternb., Utriculariaochroleuca R.W. Hartm.).

  14. Environmental Drivers of the Canadian Arctic Megabenthic Communities

    PubMed Central

    Roy, Virginie; Iken, Katrin; Archambault, Philippe

    2014-01-01

    Environmental gradients and their influence on benthic community structure vary over different spatial scales; yet, few studies in the Arctic have attempted to study the influence of environmental gradients of differing spatial scales on megabenthic communities across continental-scales. The current project studied for the first time how megabenthic community structure is related to several environmental factors over 2000 km of the Canadian Arctic, from the Beaufort Sea to northern Baffin Bay. Faunal trawl samples were collected between 2007 and 2011 at 78 stations from 30 to 1000 m depth and patterns in biomass, density, richness, diversity, and taxonomic composition were examined in relation to indirect/spatial gradients (e.g., depth), direct gradients (e.g., bottom oceanographic variables), and resource gradients (e.g., food supply proxies). Six benthic community types were defined based on their biomass-based taxonomic composition. Their distribution was significantly, but moderately, associated with large-scale (100–1000 km) environmental gradients defined by depth, physical water properties (e.g., bottom salinity), and meso-scale (10–100 km) environmental gradients defined by substrate type (hard vs. soft) and sediment organic carbon content. We did not observe a strong decline of bulk biomass, density and richness with depth or a strong increase of those community characteristics with food supply proxies, contrary to our hypothesis. We discuss how local- to meso-scale environmental conditions, such as bottom current regimes and polynyas, sustain biomass-rich communities at specific locations in oligotrophic and in deep regions of the Canadian Arctic. This study demonstrates the value of considering the scales of variability of environmental gradients when interpreting their relevance in structuring of communities. PMID:25019385

  15. The Canadian Arctic ACE/OSIRIS Validation Project at PEARL: Validating Satellite Observations Over the High Arctic

    NASA Astrophysics Data System (ADS)

    Walker, Kaley A.; Strong, Kimberly; Fogal, Pierre F.; Drummond, James R.

    2016-04-01

    Ground-based measurements provide critical data for the validation of satellite retrievals of atmospheric trace gases and for the assessment of long-term stability of these measurements. As of February 2016, the Canadian-led Atmospheric Chemistry Experiment (ACE) satellite mission has been making measurements of the Earth's atmosphere for nearly twelve years and Canada's Optical Spectrograph and InfraRed Imager System (OSIRIS) instrument on the Odin satellite has been operating for fourteen years. As ACE and OSIRIS operations have extended beyond their planned two-year missions, there is an ongoing need to validate the trace gas data profiles from the ACE-Fourier Transform Spectrometer (ACE-FTS), the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO) and OSIRIS. In particular, validation comparisons are needed during Arctic springtime to understand better the measurements of species involved in stratospheric ozone chemistry. To this end, thirteen Canadian Arctic ACE/OSIRIS Validation Campaigns have been conducted during the spring period (February - April in 2004 - 2016) at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Nunavut (80N, 86W). For the past decade, these campaigns have been undertaken in collaboration with the Canadian Network for the Detection of Atmospheric Change (CANDAC). The spring period coincides with the most chemically active time of year in the Arctic, as well as a significant number of satellite overpasses. A suite of as many as 12 ground-based instruments, as well as frequent balloon-borne ozonesonde and radiosonde launches, have been used in each campaign. These instruments include: a ground-based version of the ACE-FTS (PARIS - Portable Atmospheric Research Interferometric Spectrometer), a terrestrial version of the ACE-MAESTRO, a SunPhotoSpectrometer, two CANDAC zenith-viewing UV-visible grating spectrometers, a Bomem DA8 Fourier transform spectrometer

  16. Pollution in the Summertime Canadian High Arctic observed during NETCARE 2014: Investigation of origin and composition

    NASA Astrophysics Data System (ADS)

    Köllner, Franziska; Schneider, Johannes; Bozem, Heiko; Hoor, Peter; Willis, Megan; Burkart, Julia; Leaitch, Richard; Abbatt, Jon; Herber, Andreas; Borrmann, Stephan

    2015-04-01

    The clean and sensitive Arctic atmosphere is influenced by transport of air masses from lower latitudes that bring pollution in the form of aerosol particles and trace gases into the Arctic regions. However, the transport processes causing such pollution events are yet not sufficiently well understood. Here we report on results from the aircraft campaign NETCARE 2014 that took place in July 2014 in Resolute Bay, Nunavut (Canada) as part of the "Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environment" (NETCARE). These airborne measurements add to only a very few of such measurements conducted in the Arctic during the summertime. The instrumentation on board the research aircraft Polar 6 (operated by the Alfred Wegener Institute for Polar and Marine Research) included a large set of physico-chemical aerosol analysis instruments, several trace gas measurements and basic meteorological parameters. Here we focus on observed pollution events that caused elevated trace gas and aerosol concentrations in the summertime Canadian High Arctic between 50 and 3500 m. In order to better understand the chemical composition and the origin of those polluted air masses, we use single particle aerosol composition obtained using the Aircraft-based Laser Ablation Aerosol Mass Spectrometer (ALABAMA), combined with aerosol size distributions and number concentrations from an Optical Particle Counter as well as trace gas measurements of CO and CO2. CO and CO2 are important tracers to study pollution events, which are connected to anthropogenic and non-anthropogenic combustion processes, respectively biomass burning and fossil fuel combustion. The ALABAMA provides a detailed single particle aerosol composition analysis from which we identify different particle types like soot-, biomass burning-, organics-, diesel exhaust- and metallic particles. The measurements were compared to Lagrangian models like FLEXPART and LAGRANTO to find the pollution sources

  17. Carbon and Carbon Isotope Cycling in the Western Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Mol, Jacoba; Thomas, Helmuth

    2016-04-01

    Increasing carbon dioxide levels in the atmosphere are having drastic effects on the global oceans. The Arctic Ocean is particularly susceptible to change as warming, sea-ice loss and a weak buffering capacity all influence this complicated semi-enclosed sea. In order to investigate the inorganic carbon system in the Canadian Arctic, water samples were collected in the Beaufort Sea, on the Alaskan shelf, at the Mackenzie river delta, and in Amundsen Gulf during the summer of 2014 and were analyzed for dissolved inorganic carbon (DIC), total alkalinity (TA), DI13C and 18O isotopes. Carbon isotopes are used to investigate the role of biological production on the uptake and transfer of inorganic carbon to depth. A preferential uptake of the lighter 12C relative to the heavier 13C isotope during biological production leads to a fractionation of the 13C/12C isotopes in both the organic matter and the water column. This results in an enrichment of DI13C in the high productivity surface waters and a depletion of DI13C at depth. Physical processes including freshwater input, brine rejection, and water mass mixing are investigated through the measurement of oxygen isotopes. Differences in the carbon system across the study area due to both biological and physical processes are assessed using depth profiles of DI13C and related carbon system parameters.

  18. Gas line construction in frigid Canadian winter

    SciTech Connect

    Not Available

    1983-01-01

    Construction of a 128-mile, 42-in. gas transmission line through Precambrian rock formations in the Canadian shield proved difficult for contractors on TransCanada Pipeline's expansion program. Multiple construction problems included severe cold weather (-40/sup 0/F), a right-of-way sited midway between two live natural gas lines, and a system installed in eight different loops stretching almost 500 miles from one and to the other.

  19. Mercury in the marine environment of the Canadian Arctic: review of recent findings.

    PubMed

    Braune, Birgit; Chételat, John; Amyot, Marc; Brown, Tanya; Clayden, Meredith; Evans, Marlene; Fisk, Aaron; Gaden, Ashley; Girard, Catherine; Hare, Alex; Kirk, Jane; Lehnherr, Igor; Letcher, Robert; Loseto, Lisa; Macdonald, Robie; Mann, Erin; McMeans, Bailey; Muir, Derek; O'Driscoll, Nelson; Poulain, Alexandre; Reimer, Ken; Stern, Gary

    2015-03-15

    This review summarizes data and information which have been generated on mercury (Hg) in the marine environment of the Canadian Arctic since the previous Canadian Arctic Contaminants Assessment Report (CACAR) was released in 2003. Much new information has been collected on Hg concentrations in marine water, snow and ice in the Canadian Arctic. The first measurements of methylation rates in Arctic seawater indicate that the water column is an important site for Hg methylation. Arctic marine waters were also found to be a substantial source of gaseous Hg to the atmosphere during the ice-free season. High Hg concentrations have been found in marine snow as a result of deposition following atmospheric mercury depletion events, although much of this Hg is photoreduced and re-emitted back to the atmosphere. The most extensive sampling of marine sediments in the Canadian Arctic was carried out in Hudson Bay where sediment total Hg (THg) concentrations were low compared with other marine regions in the circumpolar Arctic. Mass balance models have been developed to provide quantitative estimates of THg fluxes into and out of the Arctic Ocean and Hudson Bay. Several recent studies on Hg biomagnification have improved our understanding of trophic transfer of Hg through marine food webs. Over the past several decades, Hg concentrations have increased in some marine biota, while other populations showed no temporal change. Marine biota also exhibited considerable geographic variation in Hg concentrations with ringed seals, beluga and polar bears from the Beaufort Sea region having higher Hg concentrations compared with other parts of the Canadian Arctic. The drivers of these variable patterns of Hg bioaccumulation, both regionally and temporally, within the Canadian Arctic remain unclear. Further research is needed to identify the underlying processes including the interplay between biogeochemical and food web processes and climate change. Crown Copyright © 2014. Published by

  20. Invasion, establishment, and range expansion of two parasitic nematodes in the Canadian Arctic

    USDA-ARS?s Scientific Manuscript database

    Climate warming is modifying host-parasite interactions in the Arctic. Invasion of an arctic island by protostrongylid nematodes appears mediated by sporadic dispersal of muskoxen and seasonal migration by caribou from the Canadian mainland. A newly permissive environment likely facilitated initial ...

  1. Atmospheric mercury in the Canadian Arctic. Part II: insight from modeling.

    PubMed

    Dastoor, Ashu; Ryzhkov, Andrew; Durnford, Dorothy; Lehnherr, Igor; Steffen, Alexandra; Morrison, Heather

    2015-03-15

    A review of mercury in the Canadian Arctic with a focus on field measurements is presented in part I (see Steffen et al., this issue). Here we provide insights into the dynamics of mercury in the Canadian Arctic from new and published mercury modeling studies using Environment Canada's mercury model. The model simulations presented in this study use global anthropogenic emissions of mercury for the period 1995-2005. The most recent modeling estimate of the net gain of mercury from the atmosphere to the Arctic Ocean is 75 Mg year(-1) and the net gain to the terrestrial ecosystems north of 66.5° is 42 Mg year(-1). Model based annual export of riverine mercury from North American, Russian and all Arctic watersheds to the Arctic Ocean are in the range of 2.8-5.6, 12.7-25.4 and 15.5-31.0 Mg year(-1), respectively. Analysis of long-range transport events of Hg at Alert and Little Fox Lake monitoring sites indicates that Asia contributes the most ambient Hg to the Canadian Arctic followed by contributions from North America, Russia, and Europe. The largest anthropogenic Hg deposition to the Canadian Arctic is from East Asia followed by Europe (and Russia), North America, and South Asia. An examination of temporal trends of Hg using the model suggests that changes in meteorology and changes in anthropogenic emissions equally contribute to the decrease in surface air elemental mercury concentrations in the Canadian Arctic with an overall decline of ~12% from 1990 to 2005. A slow increase in net deposition of Hg is found in the Canadian Arctic in response to changes in meteorology. Changes in snowpack and sea-ice characteristics and increase in precipitation in the Arctic related with climate change are found to be primary causes for the meteorology-related changes in air concentrations and deposition of Hg in the region. The model estimates that under the emissions reduction scenario of worldwide implementation of the best emission control technologies by 2020, mercury

  2. A Pliocene chronostratigraphy for the Canadian western and high Arctic

    NASA Astrophysics Data System (ADS)

    Gosse, John; Braschi, Lea; Rybczynski, Natalia; Lakeman, Thomas; Zimmerman, Susan; Finkel, Robert; Barendregt, Rene; Matthews, John

    2014-05-01

    The Beaufort Formation comprises an extensive (1200 km long, more than 1 km thick) clastic wedge that formed during the Pliocene along the western Canadian Arctic Archipelago (CAA). In the western Arctic, the Ballast Brook (BB) site on Banks Is. exposes more than 20 km of section through the sandy and pebble sandy braided stream deposits with detrital organic beds. Farther north, Beaufort Fm fluvial and estuarine facies have been examined on Meighen Is. In the high Arctic, high terrace gravels (450 m high surface) at the Fyles Leaf Bed (FLB) and Beaver Pond (BP) sites on Ellesmere Is. are not considered part of the Beaufort Fm but have similar paleoenvironmental records. Fossil plant and faunal material from these sediments is often very well preserved and provides evidence of a boreal-type forest and peatlands. The BP fossil site preserves the remains of fossil vertebrates including fish, frog, horse, beaver, deerlet, and black bear, consistent with a boreal type forest habitat. The FLB site has recently yielded the first fossil evidence for a High Arctic camel, identified with the help of collagen fingerprinting from a fragmentary limb bone (tibia). Paleoenvironmental reconstruction of the Ellesmere sites has yielded a Mean Annual Temperature of between 14 to 22 degrees Celsius warmer than today. Minimum cosmogenic nuclide burial ages of 3.4 and 3.8 Ma obtained for the BP and FLB sites, respectively, are consistent with vertebrate and floral biostratigraphic evidence. The paleoenvironmental records from the Beaufort Fm in the western CAA sites have revealed a similar ecosystem with noteworthy differences in MAT and perhaps seasonality. New burial ages from Meighen Is. indicate a maximum age of 6.1 Ma, consistent with yet much older than previous age estimates, but supportive of paleomagnetic and biostratigraphy at the same location. The age differences may account for some of the interpreted variations in paleoenvironments, in addition to spatial differences in

  3. Methanogen community composition and rates of methane consumption in Canadian High Arctic permafrost soils.

    PubMed

    Allan, J; Ronholm, J; Mykytczuk, N C S; Greer, C W; Onstott, T C; Whyte, L G

    2014-04-01

    Increasing permafrost thaw, driven by climate change, has the potential to result in organic carbon stores being mineralized into carbon dioxide (CO2) and methane (CH4) through microbial activity. This study examines the effect of increasing temperature on community structure and metabolic activity of methanogens from the Canadian High Arctic, in an attempt to predict how warming will affect microbially controlled CH4 soil flux. In situ CO2 and CH4 flux, measured in 2010 and 2011 from ice-wedge polygons, indicate that these soil formations are a net source of CO2 emissions, but a CH4 sink. Permafrost and active layer soil samples were collected at the same sites and incubated under anaerobic conditions at warmer temperatures, with and without substrate amendment. Gas flux was measured regularly and indicated an increase in CH4 flux after extended incubation. Pyrosequencing was used to examine the effects of an extended thaw cycle on methanogen diversity and the results indicate that in situ methanogen diversity, based on the relative abundance of the 16S ribosomal ribonucleic acid (rRNA) gene associated with known methanogens, is higher in the permafrost than in the active layer. Methanogen diversity was also shown to increase in both the active layer and permafrost soil after an extended thaw. This study provides evidence that although High Arctic ice-wedge polygons are currently a sink for CH4, higher arctic temperatures and anaerobic conditions, a possible result of climate change, could result in this soil becoming a source for CH4 gas flux.

  4. Influence of North Pacific decadal variability on the western Canadian Arctic over the past 700 years

    NASA Astrophysics Data System (ADS)

    Lapointe, François; Francus, Pierre; Lamoureux, Scott F.; Vuille, Mathias; Jenny, Jean-Philippe; Bradley, Raymond S.; Massa, Charly

    2017-04-01

    Understanding how internal climate variability influences arctic regions is required to better forecast future global climate variations. This paper investigates an annually-laminated (varved) record from the western Canadian Arctic and finds that the varves are negatively correlated with both the instrumental Pacific Decadal Oscillation (PDO) during the past century and also with reconstructed PDO over the past 700 years, suggesting drier Arctic conditions during high-PDO phases, and vice versa. These results are in agreement with known regional teleconnections, whereby the PDO is negatively and positively correlated with summer precipitation and mean sea level pressure respectively. This pattern is also evident during the positive phase of the North Pacific Index (NPI) in autumn. Reduced sea-ice cover during summer-autumn is observed in the region during PDO- (NPI+) and is associated with low-level southerly winds that originate from the northernmost Pacific across the Bering Strait and can reach as far as the western Canadian Arctic. These climate anomalies are associated with the PDO- (NPI+) phase and are key factors in enhancing evaporation and subsequent precipitation in this region of the Arctic. Collectively, the sedimentary evidence suggests that North Pacific climate variability has been a persistent regulator of the regional climate in the western Canadian Arctic. Since projected sea-ice loss will contribute to enhanced future warming in the Arctic, future negative phases of the PDO (or NPI+) will likely act to amplify this positive feedback.

  5. Geomagnetic Field Variability in the Western Canadian Arctic Since the Last Deglaciation

    NASA Astrophysics Data System (ADS)

    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.

    2009-12-01

    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.

  6. Survival of ship biofouling assemblages during and after voyages to the Canadian Arctic.

    PubMed

    Chan, Farrah T; MacIsaac, Hugh J; Bailey, Sarah A

    2016-01-01

    Human-mediated vectors often inadvertently translocate species assemblages to new environments. Examining the dynamics of entrained species assemblages during transport can provide insights into the introduction risk associated with these vectors. Ship biofouling is a major transport vector of nonindigenous species in coastal ecosystems globally, yet its magnitude in the Arctic is poorly understood. To determine whether biofouling organisms on ships can survive passages in Arctic waters, we examined how biofouling assemblage structure changed before, during, and after eight round-trip military voyages from temperate to Arctic ports in Canada. Species richness first decreased (~70% loss) and then recovered (~27% loss compared to the original assemblages), as ships travelled to and from the Arctic, respectively, whereas total abundance typically declined over time (~55% total loss). Biofouling community structure differed significantly before and during Arctic transits as well as between those sampled during and after voyages. Assemblage structure varied across different parts of the hull; however, temporal changes were independent of hull location, suggesting that niche areas did not provide protection for biofouling organisms against adverse conditions in the Arctic. Biofouling algae appear to be more tolerant of transport conditions during Arctic voyages than are mobile, sessile, and sedentary invertebrates. Our results suggest that biofouling assemblages on ships generally have poor survivorship during Arctic voyages. Nonetheless, some potential for transporting nonindigenous species to the Arctic via ship biofouling remains, as at least six taxa new to the Canadian Arctic, including a nonindigenous cirripede, appeared to have survived transits from temperate to Arctic ports.

  7. Elevation Changes of Ice Caps in the Canadian Arctic Archipelago

    NASA Technical Reports Server (NTRS)

    Abdalati, W.; Krabill, W.; Frederick, E.; Manizade, S.; Martin, C.; Sonntag, J.; Swift, R.; Thomas, R.; Yungel, J.; Koerner, R.

    2004-01-01

    Precise repeat airborne laser surveys were conducted over the major ice caps in the Canadian Arctic Archipelago in the spring of 1995 and 2000 in order to measure elevation changes in the region. Our measurements reveal thinning at lower elevations (below 1600 m) on most of the ice caps and glaciers, but either very little change or thickening at higher elevations in the ice cap accumulation zones. Recent increases in precipitation in the area can account for the slight thickening where it was observed, but not for the thinning at lower elevations. For the northern ice caps on the Queen Elizabeth Islands, thinning was generally less than 0.5 m/yr , which is consistent with what would be expected from the warm temperature anomalies in the region for the 5-year period between surveys and appears to be a continuation of a trend that began in the mid 1980s. Further south, however, on the Barnes and Penny ice caps on Baffin Island, this thinning was much more pronounced at over 1 m/yr in the lower elevations. Here temperature anomalies were very small, and the thinning at low elevations far exceeds any associated enhanced ablation. The observations on Barnes, and perhaps Penny are consistent with the idea that the observed thinning is part of a much longer term deglaciation, as has been previously suggested for Barnes Ice Cap. Based on the regional relationships between elevation and elevation-change in our data, the 1995-2000 mass balance for the region is estimated to be 25 cu km/yr of ice, which corresponds to a sea level increase of 0.064 mm/ yr . This places it among the more significant sources of eustatic sea level rise, though not as substantial as Greenland ice sheet, Alaskan glaciers, or the Patagonian ice fields.

  8. Elevation changes of ice caps in the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Abdalati, W.; Krabill, W.; Frederick, E.; Manizade, S.; Martin, C.; Sonntag, J.; Swift, R.; Thomas, R.; Yungel, J.; Koerner, R.

    2004-12-01

    Precise repeat airborne laser surveys were conducted over the major ice caps in the Canadian Arctic Archipelago in the spring of 1995 and 2000 in order to measure elevation changes in the region. Our measurements reveal thinning at lower elevations (below 1600 m) on most of the ice caps and glaciers but either very little change or thickening at higher elevations in the ice cap accumulation zones. Recent increases in precipitation in the area can account for the slight thickening where it was observed but not for the thinning at lower elevations. For the northern ice caps on the Queen Elizabeth Islands, thinning was generally <0.5 m yr-1, which is consistent with what would be expected from the warm temperature anomalies in the region for the 5 year period between surveys, and appears to be a continuation of a trend that began in the mid-1980s. Farther south, however, on the Barnes and Penny ice caps on Baffin Island, this thinning was much more pronounced at over 1 m yr-1 in the lower elevations. Here temperature anomalies were very small, and the thinning at low elevations far exceeds any associated enhanced ablation. The observations on Barnes, and perhaps Penny, are consistent with the idea that the observed thinning is part of a much longer term deglaciation, as has been previously suggested for Barnes ice cap. On the basis of the regional relationships between elevation and elevation change in our data, the 1995-2000 mass balance for the archipelago is estimated to be -25 km3 yr-1 of ice, which corresponds to a sea level increase of 0.064 mm yr-1. This places it among the more significant sources of eustatic sea level rise, though not as substantial as the Greenland ice sheet, Alaskan glaciers, or the Patagonian ice fields.

  9. Geological features of the northeastern Canadian Arctic margin revealed from analysis of potential field data

    NASA Astrophysics Data System (ADS)

    Anudu, Goodluck K.; Stephenson, Randell A.; Macdonald, David I. M.; Oakey, Gordon N.

    2016-11-01

    The northeastern Canadian Arctic margin is bordered to the north by Alpha Ridge, a dominantly magmatic complex within the Amerasia Basin of the Arctic Ocean, which forms part of the High Arctic Large Igneous Province (HALIP). The characteristics of the gravity and magnetic anomaly fields change notably along the Arctic margin, with two main segments recognised. Aeromagnetic and gravity data in the transition zone between these contrasting domains of the Canadian Arctic margin are analysed here in detail. Results obtained using a variety of edge enhancement (derivative) methods highlight several magnetic domains and a major offshore sedimentary basin as well as some known and a number of previously unknown tectonic and magmatic elements. A magmatic intrusion distribution map derived from the edge enhanced magnetic anomaly maps reveals that magmatic rocks are much more widespread in the relatively shallow subsurface than implied by surface geological mapping. Magmatic intrusions (mainly dykes) and other geological structures have NW-SE, NE-SW and N-S major trends. Broad gravity and pseudogravity lows across most of the Sverdrup Basin region are due to thick, less dense sedimentary succession and low magnetised crust. Magnetic and pseudogravity highs observed over Alpha Ridge indicate high crustal magnetisation associated with the occurrence of extensive and voluminous crustal magmatic bodies. Absence of these volcanic and intrusive rocks in the imaged sedimentary basin beneath the northeast Canadian Arctic margin region suggests that the basin probably formed after the cessation of HALIP magmatism.

  10. High Methylmercury in Arctic and Subarctic Ponds is Related to Nutrient Levels in the Warming Eastern Canadian Arctic.

    PubMed

    MacMillan, Gwyneth A; Girard, Catherine; Chételat, John; Laurion, Isabelle; Amyot, Marc

    2015-07-07

    Permafrost thaw ponds are ubiquitous in the eastern Canadian Arctic, yet little information exists on their potential as sources of methylmercury (MeHg) to freshwaters. They are microbially active and conducive to methylation of inorganic mercury, and are also affected by Arctic warming. This multiyear study investigated thaw ponds in a discontinuous permafrost region in the Subarctic taiga (Kuujjuarapik-Whapmagoostui, QC) and a continuous permafrost region in the Arctic tundra (Bylot Island, NU). MeHg concentrations in thaw ponds were well above levels measured in most freshwater ecosystems in the Canadian Arctic (>0.1 ng L(-1)). On Bylot, ice-wedge trough ponds showed significantly higher MeHg (0.3-2.2 ng L(-1)) than polygonal ponds (0.1-0.3 ng L(-1)) or lakes (<0.1 ng L(-1)). High MeHg was measured in the bottom waters of Subarctic thaw ponds near Kuujjuarapik (0.1-3.1 ng L(-1)). High water MeHg concentrations in thaw ponds were strongly correlated with variables associated with high inputs of organic matter (DOC, a320, Fe), nutrients (TP, TN), and microbial activity (dissolved CO2 and CH4). Thawing permafrost due to Arctic warming will continue to release nutrients and organic carbon into these systems and increase ponding in some regions, likely stimulating higher water concentrations of MeHg. Greater hydrological connectivity from permafrost thawing may potentially increase transport of MeHg from thaw ponds to neighboring aquatic ecosystems.

  11. Mercury in freshwater ecosystems of the Canadian Arctic: recent advances on its cycling and fate.

    PubMed

    Chételat, John; Amyot, Marc; Arp, Paul; Blais, Jules M; Depew, David; Emmerton, Craig A; Evans, Marlene; Gamberg, Mary; Gantner, Nikolaus; Girard, Catherine; Graydon, Jennifer; Kirk, Jane; Lean, David; Lehnherr, Igor; Muir, Derek; Nasr, Mina; Poulain, Alexandre J; Power, Michael; Roach, Pat; Stern, Gary; Swanson, Heidi; van der Velden, Shannon

    2015-03-15

    The Canadian Arctic has vast freshwater resources, and fish are important in the diet of many Northerners. Mercury is a contaminant of concern because of its potential toxicity and elevated bioaccumulation in some fish populations. Over the last decade, significant advances have been made in characterizing the cycling and fate of mercury in these freshwater environments. Large amounts of new data on concentrations, speciation and fluxes of Hg are provided and summarized for water and sediment, which were virtually absent for the Canadian Arctic a decade ago. The biogeochemical processes that control the speciation of mercury remain poorly resolved, including the sites and controls of methylmercury production. Food web studies have examined the roles of Hg uptake, trophic transfer, and diet for Hg bioaccumulation in fish, and, in particular, advances have been made in identifying determinants of mercury levels in lake-dwelling and sea-run forms of Arctic char. In a comparison of common freshwater fish species that were sampled across the Canadian Arctic between 2002 and 2009, no geographic patterns or regional hotspots were evident. Over the last two to four decades, Hg concentrations have increased in some monitored populations of fish in the Mackenzie River Basin while other populations from the Yukon and Nunavut showed no change or a slight decline. The different Hg trends indicate that the drivers of temporal change may be regional or habitat-specific. The Canadian Arctic is undergoing profound environmental change, and preliminary evidence suggests that it may be impacting the cycling and bioaccumulation of mercury. Further research is needed to investigate climate change impacts on the Hg cycle as well as biogeochemical controls of methylmercury production and the processes leading to increasing Hg levels in some fish populations in the Canadian Arctic. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  12. Holocene paleoceanography of the northwest passage, Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Ledu, David; Rochon, André; de Vernal, Anne; St-Onge, Guillaume

    2010-12-01

    A series of cores (box and piston) were collected at 2 key locations in Lancaster Sound (cores 2004-804-009 BC and PC) and Barrow Strait (cores 2005-804-004 BC and PC) in the Canadian Arctic Archipelago to document the evolution of sea-surface conditions in the main axis of the Northwest Passage during the Holocene time period. Reconstruction of sea-surface parameters (summer temperature and salinity, duration of sea-ice cover) were estimated based on transfer functions using dinoflagellate cyst assemblages as proxy indicators. The chronology of these cores is based on calibrated AMS- 14C dates, 210Pb analyses, and correlations between paleomagnetic secular variations of the geomagnetic field and a predicted spherical harmonic model of the geomagnetic field (CALS7 K.2). Our age models for both cores indicate that 009 PC spans the last 11,100 cal BP, while 004 PC encompasses the last 10,800 cal BP. Calculated sedimentation rates are in the range of 43-140 cm/kyr for core 009 PC and 15-118 cm/kyr for core 004 PC, allowing for a millennial time scale resolution in each core. Our results indicate relatively harsh conditions in Lancaster Sound between 10,800 and 9000 cal BP (summer temperatures 2 °C cooler than at present), which we associate with the presence of active ice-streams in northernmost Baffin Bay and a weak West Greenland Current. This is followed by a warming trend (up to 3 °C higher than present) that took place between ˜8500 and 5500 cal BP, which we associate with the Holocene thermal maximum and to a large scale atmospheric pattern such as the Arctic Oscillation operating at the millennial time scale. This is concomitant with an increase in the relative abundance of phototrophic dinoflagellate cyst taxa. A gradual cooling of sea-surface temperature and increased sea-ice follow this from 5500 cal BP until the modern period. In Barrow Strait, harsh sea-surface conditions prevailed from 11,100 to 5500 cal BP, with summer temperatures as low as 4

  13. Variation in peak growing season net ecosystem production across the Canadian Arctic.

    PubMed

    Lafleur, Peter M; Humphreys, Elyn R; St Louis, Vincent L; Myklebust, May C; Papakyriakou, Tim; Poissant, Laurier; Barker, Joel D; Pilote, Martin; Swystun, Kyle A

    2012-08-07

    Tundra ecosystems store vast amounts of soil organic carbon, which may be sensitive to climatic change. Net ecosystem production, NEP, is the net exchange of carbon dioxide (CO(2)) between landscapes and the atmosphere, and represents the balance between CO(2) uptake by photosynthesis and release by decomposition and autotrophic respiration. Here we examine CO(2) exchange across seven sites in the Canadian low and high Arctic during the peak growing season (July) in summer 2008. All sites were net sinks for atmospheric CO(2) (NEP ranged from 5 to 67 g C m(-2)), with low Arctic sites being substantially larger CO(2) sinks. The spatial difference in NEP between low and high Arctic sites was determined more by CO(2) uptake via gross ecosystem production than by CO(2) release via ecosystem respiration. Maximum gross ecosystem production at the low Arctic sites (average 8.6 μmol m(-2) s(-1)) was about 4 times larger than for high Arctic sites (average 2.4 μmol m(-2) s(-1)). NEP decreased with increasing temperature at all low Arctic sites, driven largely by the ecosystem respiration response. No consistent temperature response was found for the high Arctic sites. The results of this study clearly indicate there are large differences in tundra CO(2) exchange between high and low Arctic environments and this difference should be a central consideration in studies of Arctic carbon balance and climate change.

  14. Climate Effects on Methylmercury Bioaccumulation Along a Latitudinal Gradient in the Eastern Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Chetelat, J.; Richardson, M.; MacMillan, G. A.; Amyot, M.; Hintelmann, H.; Crump, D.

    2014-12-01

    Recent evidence indicates that inorganic mercury (Hg) loadings to Arctic lakes decline with latitude. However, monomethylmercury (MMHg) concentrations in fish and their prey do not decline in a similar fashion, suggesting that higher latitude lakes are more vulnerable to Hg inputs. Preliminary results will be presented from a three-year study (2012-2015) of climate effects on MMHg bioaccumulation in lakes of the eastern Canadian Arctic. We have investigated mercury transport and accumulation processes in lakes and ponds from three study regions along a latitudinal gradient in climate-controlled ecosystem types in the Canadian Arctic, specifically sub-Arctic taiga, Arctic tundra and polar desert. In each water body, we measured key aspects of MMHg bioaccumulation—MMHg bioavailability to benthic food webs and organism growth rates—as well as how watershed characteristics affect the transport of Hg and organic carbon to lakes. Novel approaches were incorporated including the use of passive samplers (Diffusive Gradient in Thin Film samplers or DGTs) to estimate sediment bioavailable MMHg concentrations and tissue RNA content to compare organism short-term growth rates. A comparison of Arctic tundra and sub-Arctic taiga lakes showed that surface water concentrations of MMHg were strongly and positively correlated to total Hg concentrations both within and among study regions, implying strong control of inorganic Hg supply. Sediment concentrations of bioavailable MMHg were highly variable among lakes, although average concentrations were similar between study regions. Local environmental conditions appear to have a strong influence on sediment potential for MMHg supply. Lake-dwelling Arctic char from tundra lakes had similar or higher total Hg concentrations compared with brook trout from sub-Arctic lakes that were exposed to higher water MMHg concentrations. Potential environmental drivers of these patterns will be discussed. This latitudinal study will provide new

  15. DBAE in an Arctic Fine Arts Program for Indigenous Canadian College Students.

    ERIC Educational Resources Information Center

    McNeal, Joanne

    1997-01-01

    Details the setting and context of a college-level fine arts program at Aurora College in the Canadian Arctic that drew adult students from several indigenous cultures. Offers an account of how Discipline-Based Art Education shaped the design of the program, and how it worked in the teaching and learning process. (DSK)

  16. Observed and Projected Variability of Snow Cover and Sea Ice in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Howell, Stephen; Derksen, Chris; Kushner, Paul; Laliberte, Frederic; Mudryk, Lawrence; Sospedra-Alfonso, Reinel; Thackeray, Chad

    2017-04-01

    Rigorous comparisons of climate model simulations with observations over the past century and robust projections into the coming seasons, years and decades are essential in order to determine the impact of a changing cryosphere on the global climate system. The Canadian Sea Ice and Snow Evolution Network (CanSISE) is a climate research network focused on developing state of the art observational data for comparison with earth system models to advance observation, prediction, and understanding of seasonal snow cover and sea ice in Canada and the circumpolar Arctic. Here, we summarize variability and trends in the historical record of snow cover (fraction, water equivalent and duration) and sea ice (area, concentration, type and thickness) in the Canadian Arctic. We also provide an assessment of snow cover and sea ice future variability and change, likely to occur by mid-century, as simulated by the Coupled Model Intercomparison Project Phase 5 (CMIP5) suite of climate models. To put regional conditions in a larger context, the observed and projected changes over the Canadian Arctic are compared to the pan-Arctic. Finally, we discuss how these observed and projected changes in the snow cover and sea ice components of the Canadian cryosphere have important implications for human activity including the close ties of northerners to the land, access to northern regions for natural resource development, establishing new up-to-date shipping routes, and the integrity of northern infrastructure.

  17. DBAE in an Arctic Fine Arts Program for Indigenous Canadian College Students.

    ERIC Educational Resources Information Center

    McNeal, Joanne

    1997-01-01

    Details the setting and context of a college-level fine arts program at Aurora College in the Canadian Arctic that drew adult students from several indigenous cultures. Offers an account of how Discipline-Based Art Education shaped the design of the program, and how it worked in the teaching and learning process. (DSK)

  18. Canadian Arctic Plate Reconstructions based on revised geological and geophysical data

    NASA Astrophysics Data System (ADS)

    Torsvik, Trond H.; Gaina, Carmen

    2015-04-01

    We present a revised rifting and seafloor spreading history around Greenland based on geological and geophysical constraints. Palaeomagnetic data from (i) Neoproterozoic dykes and sills in North America, NW Greenland, Devon and SW Ellesmere (Franklin and Clarence Head), (ii) Early Permian volcanism (Esayoo unit) in Ellesmere and (iii) Cretaceous volcanism and intrusive activity (Isachsen and Strandfjord Formations) in Axel Heiberg and Ellesmere have also been re-evaluated and used to develop a new Canadian Arctic plate model from Silurian to Paleogene times. We have tentatively divided the Canadian Arctic into seven tectonic units, including Pearya, which accreted to the northern sectors of Ellesmere and Axel Heiberg islands as part of the mid-Silurian Caledonide Orogeny. The Canadian Arctic was variable deformed during the Late Devonian Ellesmere and the Tertiary Eurekean events, the latter including c. 250 km of shortening and ultimately amalgamating all the Canadian Arctic units in the Late Eocene. Two of the units, Devon and SW Ellesmere must have been closely tied to NW Greenland (the 'Greenland Plate') in order to minimize Palaeocene-Eocene deformation across the Nares Strait during Labrador Sea and Baffin Bay seafloor spreading. We model 100 and 60 km of Late Cretaceous-Eocene transtension/extension in the Lancaster and Jones Sounds but in order to avoid too much continental overlap between Devon and North America (Lancaster Sound) we must include 150 km of pure strike-slip faulting along the Nares Strait.

  19. Arctic Gas hydrate, Environment and Climate

    NASA Astrophysics Data System (ADS)

    Mienert, Jurgen; Andreassen, Karin; Bünz, Stefan; Carroll, JoLynn; Ferre, Benedicte; Knies, Jochen; Panieri, Giuliana; Rasmussen, Tine; Myhre, Cathrine Lund

    2015-04-01

    Arctic methane hydrate exists on land beneath permafrost regions and offshore in shelf and continental margins sediments. Methane or gas hydrate, an ice-like substrate, consists mainly of light hydrocarbons (mostly methane from biogenic sources but also ethane and propane from thermogenic sources) entrapped by a rigid cage of water molecules. The pressure created by the overlying water and sediments offshore stabilizes the CH4 in continental margins at a temperature range well above freezing point; consequently CH4 exists as methane ice beneath the seabed. Though the accurate volume of Arctic methane hydrate and thus the methane stored in hydrates throughout the Quaternary is still unknown it must be enormous if one considers the vast regions of Arctic continental shelves and margins as well as permafrost areas offshore and on land. Today's subseabed methane hydrate reservoirs are the remnants from the last ice age and remain elusive targets for both unconventional energy and as a natural methane emitter influencing ocean environments and ecosystems. It is still contentious at what rate Arctic warming may govern hydrate melting, and whether the methane ascending from the ocean floor through the hydrosphere reaches the atmosphere. As indicated by Greenland ice core records, the atmospheric methane concentration rose rapidly from ca. 500 ppb to ca. 750 ppb over a short time period of just 150 years at the termination of the younger Dryas period ca. 11600 years ago, but the dissociation of large quantities of methane hydrates on the ocean floor have not been documented yet (Brook et al., 2014 and references within). But with the major projected warming and sea ice melting trend (Knies et al., 2014) one may ask, for how long will CH4 stay trapped in methane hydrates if surface and deep-ocean water masses will warm and permafrost continuous to melt (Portnov et al. 2014). How much of the Arctic methane will be consumed by the micro- and macrofauna, how much will

  20. Shelf Exchange Processes of CO2, Ra, and Ba in the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Thomas, Helmuth; Dehairs, Frank; Mol, Jacoba

    2017-04-01

    The Canadian Arctic Archipelago has been sampled during the Canadian GEOTRACES program in summer 2015. In Baffin Bay and Archipelagic waters dissolved inorganic carbon (DIC), alkalinity (AT), and barium (Ba) measurements have been performed, which were paralleled at selected stations by measurements of the two short-lived radium isotopes 223Ra and 224Ra. Using these observations we investigate relevant transport processes within the Canadian Arctic Archipelago: lateral and vertical diffusion from the sediments, river runoff, transport of water masses through the Archipelago and inflow of water masses of Atlantic and Pacific origin, respectively into the Archipelago. The impact of theses processes on the biogeochemistry, and in particular ocean acidification will be assessed.

  1. Inter- and intraclutch variation in egg mercury levels in marine bird species from the Canadian Arctic.

    PubMed

    Akearok, Jason A; Hebert, Craig E; Braune, Birgit M; Mallory, Mark L

    2010-01-15

    Mercury (Hg) is a toxic metal that has been of increasing concern in the Canadian Arctic. We measured total Hg in eggs of three marine birds (Arctic terns Sterna paradisaea, common eiders Somateria mollissima borealis, long-tailed ducks Clangula hyemalis) that breed in the Canadian Arctic, to compare Hg laying order effects from the same clutch and to examine Hg among species. Early-laid eggs of all three species had 24-48% higher Hg concentrations than late laid eggs. Arctic terns had approximately twice the concentration of Hg in their eggs as the two duck species, and Hg in eider eggs from the High Arctic was higher than Hg in eggs from the Low Arctic. Higher Hg in tern eggs was consistent with this species occupying a higher trophic position in marine food webs, as indicated by stable nitrogen isotope (delta(15)N) values. The egg-laying sequence may need to be considered for Hg biomonitoring studies where small samples sizes are planned, and early eggs may be preferable for such studies since early eggs may be more representative of potential maximum levels of Hg in the marine food webs.

  2. Circumpolar oil-and-gas-bearing basins of the arctic part of the North American continent

    NASA Astrophysics Data System (ADS)

    Zabanbark, A.; Lobkovsky, L. I.

    2015-09-01

    Major geotectonic elements of the reviewed territory of the Arctic part of the North American continent are the Hyperborean Precambrian Platform, the Franklin folding belt, the northern part of the Precambrian Canadian platform, and the Mesozoic folding belt of Canada and Alaska. The rise of the Arctic slope of Alaska, the Beaufort Sea, and the Sverdrup basin are located in the southern margins of the Hyperborean Platform. The structure and peculiarities of development of these structural elements are genetically related to the evolution of this platform, as well as the current state of petroleum potential of the most promising exploration region of Arctic in the 21st century. The forced exploration of the Arctic regions of the United States and Canada has become an important milestone in the current development of the world energetics. Up to 100 oil, gas, and gas condensate fields have been discovered as a result of violent studies, and the potential oil and gas reserves in the Arctic part of the North American continent have been estimated to 30 billiion t and 50 trillion cubic meters, respectively. Many prospects are related to the continental slopes of all three above-mentioned basins; the total potential reserves of slopes are estimated as 10-12 billion t of oil and 20-25 trillion cubic meters of gas.

  3. Mineralogical, geochemical, and magnetic signatures of surface sediments from the Canadian Beaufort Shelf and Amundsen Gulf (Canadian Arctic)

    NASA Astrophysics Data System (ADS)

    Gamboa, Adriana; Montero-Serrano, Jean-Carlos; St-Onge, Guillaume; Rochon, André; Desiage, Pierre-Arnaud

    2017-02-01

    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.

  4. Spatial and temporal trends of contaminants in terrestrial biota from the Canadian Arctic.

    PubMed

    Gamberg, Mary; Braune, Birgit; Davey, Eric; Elkin, Brett; Hoekstra, Paul F; Kennedy, David; Macdonald, Colin; Muir, Derek; Nirwal, Amar; Wayland, Mark; Zeeb, Barbara

    2005-12-01

    Contaminants in the Canadian Arctic have been studied over the last twelve years under the guidance of the Northern Contaminants Program. This paper summarizes results from that program from 1998 to 2003 with respect to terrestrial animals in the Canadian Arctic. The arctic terrestrial environment has few significant contaminant issues, particularly when compared with freshwater and marine environments. Both current and historical industrial activities in the north may have a continuing effect on biota in the immediate area, but effects tend to be localized. An investigation of arctic ground squirrels at a site in the Northwest Territories that had historically received applications of DDT concluded that DDT in arctic ground squirrels livers was the result of contamination and that this is an indication of the continuing effect of a local point source of DDT. Arsenic concentrations were higher in berries collected from areas around gold mines in the Northwest Territories than from control sites, suggesting that gold mining may significantly affect arsenic levels in berries in the Yellowknives Dene traditional territory. Although moose and caribou from the Canadian Arctic generally carry relatively low contaminant burdens, Yukon moose had high renal selenium concentrations, and moose and some woodland caribou from the same area had high renal cadmium levels, which may put some animals at risk of toxicological effects. Low hepatic copper levels in some caribou herds may indicate a shortage of copper for metabolic demands, particularly for females. Similarities in patterns of temporal fluctuations in renal element concentrations for moose and caribou suggest that environmental factors may be a major cause of fluctuations in renal concentrations of some elements. Concentrations of persistent organochlorines and metals in beaver and muskrat from the Northwest Territories, and carnivores from across the Canadian Arctic were very low and considered normal for terrestrial

  5. A geographical comparison of mercury in seabirds in the eastern Canadian Arctic.

    PubMed

    Braune, Birgit M; Gaston, Anthony J; Grant Gilchrist, H; Mallory, Mark L; Provencher, Jennifer F

    2014-05-01

    Mercury (Hg) is a potentially toxic metal ubiquitous in arctic biota. Livers of adult thick-billed murres (Uria lomvia) and northern fulmars (Fulmarus glacialis) sampled from several locations in the eastern Canadian Arctic during 2007-2008 were analyzed for total Hg in order to assess geographical patterns. Thick-billed murres were collected from five colonies (Coats Island, Digges Island, Akpatok Island, Prince Leopold Island, Minarets) and northern fulmars from two colonies (Prince Leopold Island, Minarets). Murres at the two high Arctic colonies of Prince Leopold Island and the Minarets had significantly higher (two-fold) Hg concentrations (4.13 ± 019 μg g(-1) dw and 4.41 ± 0.33 μg g(-1) dw, respectively) than at the three low Arctic colonies (colony means of 1.62, 1.99 and 2.15 μg g(-1) dw). The differences in Hg concentrations observed between high and low Arctic murre colonies may reflect a combination of different source regions for Hg, as well as a recent dietary shift among low Arctic murres. Fulmars from Prince Leopold Island had significantly higher Hg levels (6.99 ± 1.13 μg g(-1) dw) than those from the Minarets (3.42 ± 0.53 μg g(-1) dw) which may reflect different Hg deposition and methylation patterns on both summer and winter feeding areas. Although there is no evidence linking Hg to adverse population effects in either murres or fulmars at the colonies sampled, levels in some Canadian Arctic marine birds have increased over recent decades and, therefore, continued monitoring, particularly of the high Arctic colonies, is warranted. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  6. Fast ice in the Canadian Arctic: Climatology, Atmospheric Forcing and Relation to Bathymetry

    NASA Astrophysics Data System (ADS)

    Galley, R. J.; Barber, D. G.

    2010-12-01

    Mobile sea ice in the northern hemisphere has experienced significant reductions in both extent and thickness over the last thirty years, and global climate models agree that these decreases will continue. However, the Canadian Arctic Archipelago (CAA) creates a much different icescape than in the central Arctic Ocean due to its distinctive topographic, bathymetric and climatological conditions. Of particular interest is the continued viability of landfast sea ice as a means of transportation and platform for transportation and hunting for the Canadian Inuit that reside in the region, as is the possibility of the Northwest Passage becoming a viable shipping lane in the future. Here we determine the climatological average landfast ice conditions in the Canadian Arctic Archipelago over the last 27 years, we investigate variability and trends in these landfast ice conditions, and we attempt to elucidate the physical parameters conducive to landfast sea ice formation in sub-regions of the CAA during different times of the year. We use the Canadian Ice Service digital sea ice charts between 1983 and 2009 on a 2x2km grid to determine the sea ice concentration-by-type and whether the sea ice in a grid cell was landfast on a weekly, bi-weekly or monthly basis depending on the time of year. North American Regional Reanalysis (NARR) atmospheric data were used in this work, including air temperature, surface level pressure and wind speed and direction. The bathymetric data employed was from the International Bathymetric Chart of the Arctic Ocean. Results indicate that the CAA sea ice regime is not climatologically analogous to the mobile sea ice of the central Arctic Ocean. The sea ice and the atmospheric and bathymetric properties that control the amount and timing of landfast sea ice within the CAA are regionally variable.

  7. VHF and UHF propagation in the Canadian high Arctic

    NASA Astrophysics Data System (ADS)

    Butler, R. S.; Strickland, J. I.; Bilodeau, C.

    1984-02-01

    Radio propagation in the Arctic maritime environment was studied. Five UHF radio paths between pairs of elevated points were selected along a 300 km east-west line which parallels a potentially important navigation route through the Arctic islands. Two VHF paths, each between an elevated site and a point near sea level were also chosen to simulate communications with a ship. Partial results from the summer to winter transition season show that propagation between the elevated points is highly reliable, but that propagation along the slanted paths appears to be strongly affected by radio wave ducting.

  8. Modern to millennium-old greenhouse gases emitted from freshwater ecosystems of the eastern Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Bouchard, F.; Laurion, I.; Preskienis, V.; Fortier, D.; Xu, X.; Whiticar, M. J.

    2015-07-01

    Ponds and lakes are widespread across the rapidly changing permafrost environments. Aquatic systems play an important role in global biogeochemical cycles, especially in greenhouse gas (GHG) exchanges between terrestrial systems and the atmosphere. The source, speciation and emission of carbon released from permafrost landscapes are strongly influenced by local specific conditions rather than general environmental setting. This study reports on GHG ages and emission rates from aquatic systems on Bylot Island in the eastern Canadian Arctic. Dissolved and ebullition gas samples were collected during the summer season from different types of water bodies located in a highly dynamic periglacial valley: polygonal ponds, collapsed ice-wedge trough ponds, and larger lakes overlying unfrozen soils (talik). The results showed strikingly different ages and fluxes depending on aquatic system types. Polygonal ponds were net sinks of dissolved CO2, but variable sources of dissolved CH4. They presented the highest ebullition fluxes, one or two orders of magnitude higher than from other ponds and lakes. Trough ponds appeared as substantial GHG sources, especially when their edges were actively eroding. Both types of ponds produced modern to hundreds of years old (<550 yr BP) GHG, even if trough ponds could contain much older carbon (>2000 yr BP) derived from freshly eroded peat. Lakes had small dissolved and ebullition fluxes, however they released much older GHG, including millennium-old CH4 (up to 3500 yr BP) sampled from lake central areas. Acetoclastic methanogenesis dominated at all study sites and there was minimal, if any, methane oxidation in gas emitted through ebullition. These findings provide new insights on the variable role of permafrost aquatic systems as a positive feedback mechanism on climate.

  9. An Integrated Bathymetric and Topographic Digital Terrain Model of the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Alm, G.; Macnab, R.; Jakobsson, M.; Kleman, J.; McCracken, M.

    2002-12-01

    Currently, the International Bathymetric Chart of the Arctic Ocean (IBCAO) [Jakobsson et al. 2000], contains the most up-to-date digital bathymetric model of the entire Canadian Arctic Archipelago. IBCAO is a seamless bathymetric/topographic Digital Terrain Model (DTM) that incorporates three primary data sets: all available bathymetric data at the time of compilation; the US Geological Survey GTOPO30 topographic data; and the World Vector Shoreline for coastline representation. The horizontal grid cell size is 2.5 x 2.5 km on a Polar Stereographic projection, which is adequate for regional visualization and analysis, but which may not be sufficient for certain geoscientific and oceanographic applications. However, the database that was constructed during the IBCAO project holds bathymetric data of a high quality throughout most of the Canadian Arctic Archipelago, justifying a compilation resolution that is better than 2.5 x 2.5 km. This data is primarily from historical hydrographic surveys that were carried out by the Canadian Hydrographic Survey (CHS). The construction of a higher resolution bathymetry/topography DTM of the Canadian Arctic Archipelago (complete with an error estimation of interpolated grid cells) requires a consideration of historical metadata which contains detailed descriptions of horizontal and vertical datums, positioning systems, and the depth sounding systems that were deployed during individual surveys. A significant portion of this metadata does not exist in digital form; it was not available during the IBCAO compilation, although due to the relatively low resolution of the original DTM (2.5 x 2.5 km), its absence was considered a lesser problem. We have performed "data detective" work and have extracted some of the more crucial metadata from CHS archives and are thus able to present a preliminary version of a seamless Digital Terrain Model of the Canadian Arctic Archipelago. This represents a significant improvement over the original

  10. Implications of a Changing Arctic on Summertime Surface Seawater pCO2 Variations in the Eastern Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Burgers, T.; Miller, L. A.; Thomas, H.; Else, B. G. T.; Gosselin, M.; Papakyriakou, T. N.

    2015-12-01

    Arctic marine carbonate chemistry and rates of air-sea CO2 exchange are anticipated to be affected by current changes in sea-ice structure and extent, freshwater inputs, ocean circulation patterns, and the seasonality of phytoplankton blooms. This study examines how such changes will impact rates of air-sea CO2 exchange in northern Baffin Bay, Nares Strait, and the eastern Canadian Arctic Archipelago. This complex oceanographic region includes the North Water polynya; one of the most biologically productive areas in the Arctic Ocean, and the convergence site of the warm West Greenland Current with cold exported Arctic waters. Continuous measurements of atmospheric and surface seawater CO2 (pCO2) were collected onboard the Canadian Coast Guard Ship Amundsen during its 2013 and 2014 summer cruises. Surface seawater pCO2 displayed considerable variability (145 - 389 ppm), but never exceeded atmospheric concentrations. Calculated CO2 fluxes ranged from 0 to -45 mmol m-2 day-1 (oceanic uptake), and were estimated using the Sweeney et al. (2007) parameterization with in-situ wind speed measurements. Ancillary measurements of chlorophyll a reveal low productivity in surface waters during mid-summer with isolated sub-surface blooms. This is likely the result of nutrient limitation within the highly stratified polar mixed layer (PML). Measurements of stable oxygen isotope ratios (δ18O) and total alkalinity were used to estimate freshwater inputs (sea-ice melt vs. meteoric water) to the PML. These and in-situ observations of sea ice cover were used to interpret seawater pCO2 variations. Surface waters influenced by sea-ice melt exhibit lower pCO2 than those influenced by meteoric water. The results of this investigation shed light on the future role of this region as a summertime sink of atmospheric CO2.

  11. Spatial variability of factors influencing coastal change in the Western Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Manson, G. K.; Solomon, S. M.; Forbes, D. L.; Atkinson, D. E.; Craymer, M.

    2005-06-01

    Coastal change in the western Canadian Arctic is influenced by coastal morphology, relative sea-level trend and sea-ice and storm climates. The spatial variability of these factors tends to follow general east west trends suggesting similar trends in coastal erosion hazard, processes and rates of coastal change. The spatial variability in the causes of coastal change is examined in the communities of Tuktoyaktuk, Sachs Harbour, Holman and Kugluktuk.

  12. Sharply increased mass loss from glaciers and ice caps in the Canadian Arctic Archipelago.

    PubMed

    Gardner, Alex S; Moholdt, Geir; Wouters, Bert; Wolken, Gabriel J; Burgess, David O; Sharp, Martin J; Cogley, J Graham; Braun, Carsten; Labine, Claude

    2011-05-19

    Mountain glaciers and ice caps are contributing significantly to present rates of sea level rise and will continue to do so over the next century and beyond. The Canadian Arctic Archipelago, located off the northwestern shore of Greenland, contains one-third of the global volume of land ice outside the ice sheets, but its contribution to sea-level change remains largely unknown. Here we show that the Canadian Arctic Archipelago has recently lost 61 ± 7 gigatonnes per year (Gt yr(-1)) of ice, contributing 0.17 ± 0.02 mm yr(-1) to sea-level rise. Our estimates are of regional mass changes for the ice caps and glaciers of the Canadian Arctic Archipelago referring to the years 2004 to 2009 and are based on three independent approaches: surface mass-budget modelling plus an estimate of ice discharge (SMB+D), repeat satellite laser altimetry (ICESat) and repeat satellite gravimetry (GRACE). All three approaches show consistent and large mass-loss estimates. Between the periods 2004-2006 and 2007-2009, the rate of mass loss sharply increased from 31 ± 8 Gt yr(-1) to 92 ± 12 Gt yr(-1) in direct response to warmer summer temperatures, to which rates of ice loss are highly sensitive (64 ± 14 Gt yr(-1) per 1 K increase). The duration of the study is too short to establish a long-term trend, but for 2007-2009, the increase in the rate of mass loss makes the Canadian Arctic Archipelago the single largest contributor to eustatic sea-level rise outside Greenland and Antarctica.

  13. Preliminary assessment of geological applications of ERTS-1 imagery from selected areas of the Canadian Arctic

    NASA Technical Reports Server (NTRS)

    Gregory, A. F.

    1973-01-01

    An assessment of geological applications of ERTS-1 imagery from selected areas of the Canadian Arctic is presented. The three levels of interpretation which may be recognized and employed to derive information from a single image or data format are outlined. It is stated that one immediate benefit from ERTS will be improved efficiency in planning for and operation of programs of regional geological mapping. Imagery of various areas of Canada are presented to show applications to regional mapping.

  14. NOAA WP-3D instrumentation and flight operations on AGASP-II. [Arctic Gas and Aerosol Sampling Program

    NASA Technical Reports Server (NTRS)

    Schnell, R. C.; Watson, T. B.; Bodhaine, B. A.

    1989-01-01

    One component of the second Arctic Gas and Aerosol Sampling Program conducted in March and April 1986 was supported with an instrumented NOAA WP-3D atmospheric research aircraft, which was used to conduct measurements of wind, temperature, ozone, water vapor, the concentration of condensation nuclei, and aerosol scattering extinction coefficient in order to determine the locations and properties of haze layers. The WP-3D flights consisted of three missions north of Alaska and three in the Canadian Arctic near Alert. This paper describes the NOAA WP-3D aircraft; the meteorological, gas, and aerosol sampling systems utilized; and the flight operations of the six WP-3D flights.

  15. Trace element concentrations and gastrointestinal parasites of Arctic terns breeding in the Canadian High Arctic.

    PubMed

    Provencher, J F; Braune, B M; Gilchrist, H G; Forbes, M R; Mallory, M L

    2014-04-01

    Baseline data on trace element concentrations are lacking for many species of Arctic marine birds. We measured essential and non-essential element concentrations in Arctic tern (Sterna paradisaea) liver tissue and brain tissue (mercury only) from Canada's High Arctic, and recorded the presence/absence of gastrointestinal parasites during four different phases of the breeding season. Arctic terns from northern Canada had similar trace element concentrations to other seabird species feeding at the same trophic level in the same region. Concentrations of bismuth, selenium, lead and mercury in Arctic terns were high compared to published threshold values for birds. Selenium and mercury concentrations were also higher in Arctic terns from northern Canada than bird species sampled in other Arctic areas. Selenium, mercury and arsenic concentrations varied across the time periods examined, suggesting potential regional differences in the exposure of biota to these elements. For unknown reasons, selenium concentrations were significantly higher in birds with gastrointestinal parasites as compared to those without parasites, while bismuth concentrations were higher in Arctic terns not infected with gastrointestinal parasites. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Is Submarine Groundwater Discharge a Gas Hydrate Formation Mechanism on the Circum-Arctic Shelf?

    NASA Astrophysics Data System (ADS)

    Frederick, J. M.; Buffett, B. A.

    2015-12-01

    Methane hydrate is an ice-like solid that can sequester large quantities of methane gas in marine sediments along most continental margins where thermodynamic conditions permit its formation. Along the circum-Arctic shelf, relict permafrost-associated methane hydrate deposits formed when non-glaciated portions of the shelf experienced subaerial exposure during ocean transgressions. Gas hydrate stability and the permeability of circum-Arctic shelf sediments to gas migration is closely linked with relict submarine permafrost. Heat flow observations on the Alaskan North Slope and Canadian Beaufort Shelf suggest the movement of groundwater offshore, but direct observations of groundwater flow do not exist. Submarine discharge, an offshore flow of fresh, terrestrial groundwater, can affect the temperature and salinity field in shelf sediments, and may be an important factor in submarine permafrost and gas hydrate evolution on the Arctic continental shelf. Submarine groundwater discharge may also enhance the transport of organic matter for methanogenesis within marine sediments. Because it is buoyancy-driven, the velocity field contains regions with a vertical (upward) component as groundwater flows offshore. This combination of factors makes submarine groundwater discharge a potential mechanism controlling permafrost-associated gas hydrate evolution on the Arctic continental shelf. In this study, we quantitatively investigate the feasibility of submarine groundwater discharge as a control on permafrost-associated gas hydrate formation on the Arctic continental shelf, using the Canadian Beaufort Shelf as an example. We have developed a shelf-scale, two-dimensional numerical model based on the finite volume method for two-phase flow of pore fluid and methane gas within Arctic shelf sediments. The model tracks the evolution of the pressure, temperature, salinity, methane gas, methane hydrate, and permafrost fields given imposed boundary conditions, with latent heat of

  17. Mercury and cadmium in ringed seals in the Canadian Arctic: Influence of location and diet.

    PubMed

    Brown, Tanya M; Fisk, Aaron T; Wang, Xiaowa; Ferguson, Steven H; Young, Brent G; Reimer, Ken J; Muir, Derek C G

    2016-03-01

    Concentrations of total mercury (THg) and total cadmium (TCd) were determined in muscle and liver of ringed seals (Pusa hispida) from up to 14 locations across the Canadian Arctic. Location, trophic position (TP) and relative carbon source best predicted the THg and TCd concentrations in ringed seals. THg concentrations in ringed seals were highest in the western Canadian Arctic (Beaufort Sea), whereas TCd was highest in the eastern Canadian Arctic (Hudson Bay and Labrador). A positive relationship between THg and TP and a negative relationship between THg and relative carbon source contributed to the geographical patterns observed and elevated THg levels at certain sites. In contrast, a negative relationship between TCd and TP was found, indicating that high TCd concentrations are related to seals feeding more on invertebrates than fish. Feeding ecology appears to play an important role in THg and TCd levels in ringed seals, with biomagnification driving elevated THg levels and a dependence on low-trophic position prey resulting in high TCd concentrations. The present study shows that both natural geological differences and diet variability among regions explain the spatial patterns for THg and TCd concentrations in ringed seals.

  18. Logistical problems associated with painting projects in the Canadian Arctic

    SciTech Connect

    Prinsloo, H.F.

    1995-12-01

    Planning for the application of protective coatings in the high Arctic has to start several years before the actual work is expected to be performed. Ensuring that the materials, equipment and manpower come together at the right place and the right time is a logistics feat not easily achieved by the inexperienced. This paper will address the planning of material purchase, transport and on-site storage, as well as the provision of the necessary equipment to perform the required surface preparation and application. The availability (or lack of availability) of skilled manpower in the remote settlements of the Arctic will be discussed, as well as possible training programs to enable local personnel to execute some or all of the maintenance painting programs.

  19. Sea ice conditions and melt season duration variability within the Canadian Arctic Archipelago: 1979-2008

    NASA Astrophysics Data System (ADS)

    Howell, Stephen E. L.; Duguay, Claude R.; Markus, Thorsten

    2009-05-01

    Sea ice conditions and melt season duration within the Canadian Arctic Archipelago (CAA) were investigated from 1979-2008. The CAA is exhibiting statistically significant decreases in average September total sea ice area at -8.7% decade-1. The melt season duration within the CAA is increasing significantly at 7 days decade-1. 2008 represented the longest melt season duration within the CAA over the satellite record at 129 days. Average September multi-year ice (MYI) area is decreasing at -6.4% decade-1 but has yet to reach statistical significance as a result of increasing MYI dynamic import from the Arctic Ocean. Results also find that the Western Parry Channel (WPC) region of the Northwest Passage (NWP) will continue to be susceptible to MYI as the transition to a summer-time sea ice free Arctic continues. The processes responsible for the temporary clearing of the WPC region of the NWP in 2007 were also identified.

  20. Facies patterns and conodont biogeography in Arctic Alaska and the Canadian Arctic Islands: Evidence against juxtaposition of these areas during early Paleozoic time

    USGS Publications Warehouse

    Dumoulin, J.A.; Harris, A.G.; Bradley, D.C.; De Freitas, T. A.

    2000-01-01

    Differences in lithofacies and biofacies suggest that lower Paleozoic rocks now exposed in Arctic Alaska and the Canadian Arctic Islands did not form as part of a single depositional system. Lithologic contrasts are noted in shallow- and deep-water strata and are especially marked in Ordovician and Silurian rocks. A widespread intraplatform basin of Early and Middle Ordovician age in northern Alaska has no counterpart in the Canadian Arctic, and the regional drowning and backstepping of the Silurian shelf margin in Canada has no known parallel in northern Alaska. Lower Paleozoic basinal facies in northern Alaska are chiefly siliciclastic, whereas resedimented carbonates are volumetrically important in Canada. Micro- and macrofossil assemblages from northern Alaska contain elements typical of both Siberian and Laurentian biotic provinces; coeval Canadian Arctic assemblages contain Laurentian forms but lack Siberian species. Siberian affinities in northern Alaskan biotas persist from at least Middle Cambrian through Mississippian time and appear to decrease in intensity from present-day west to east. Our lithologic and biogeographic data are most compatible with the hypothesis that northern Alaska-Chukotka formed a discrete tectonic block situated between Siberia and Laurentia in early Paleozoic time. If Arctic Alaska was juxtaposed with the Canadian Arctic prior to opening of the Canada basin, biotic constraints suggest that such juxtaposition took place no earlier than late Paleozoic time.

  1. Carbon Cycling in Permafrost Aquatic Systems of Bylot Island, Eastern Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Bouchard, F.; Preskienis, V.; Laurion, I.; Fortier, D.

    2014-12-01

    Aquatic systems are widespread in permafrost environments and play a crucial role in biogeochemical cycles, especially in GHG emissions (CO2, CH4). Amount, rate and age of carbon released from permafrost thawing can be strongly influenced by local geomorphology, which affects the biogeochemical dynamics of ponds and lakes. Bylot Island (Nunavut) is located in the heart of the Eastern Canadian Arctic and comprises numerous glacial and periglacial aquatic landscapes. Several glacial valleys of the island represent highly dynamic biogeosystems rich in permafrost ground ice, peat, and aquatic environments. We aimed at characterizing the influence of geomorphology and permafrost degradation processes on aquatic system biogeochemistry. We sampled gas, water, permafrost and lacustrine sediment in different types of aquatic systems: polygonal ponds, collapsed ice-wedge trough ponds, and larger lakes overlying unfrozen soil ('talik'). Preliminary results and field observations indicate a relationship between pond/lake morphology, processes of permafrost degradation, and the age of carbon processed - ultimately released as GHG - in these aquatic systems. Small and shallow ponds produced modern or young (< 500 yr BP) CO2 and CH4, whereas larger and deeper lakes released older (< 2000 yr BP) gases. We also observed a substantial difference in gas fluxes between similar ponds of comparable size and depth. When pond margins were actively eroding (eroded and collapsed peat blocks), fluxes were several orders of magnitude higher than when their margins were stabilized. Such findings underscore the strong impact of local geomorphology and permafrost degradation processes on aquatic system biogeochemistry. Upscaling of GHG emissions at the watershed scale requires a better understanding of the emissions from different types of ecosystems.

  2. New evidence from the western Canadian Arctic Archipelago for the resubmergence of Bering Strait

    NASA Astrophysics Data System (ADS)

    England, John H.; Furze, Mark F. A.

    2008-07-01

    Widespread molluscan samples were collected from raised marine sediments to date the last retreat of the NW Laurentide Ice Sheet from the western Canadian Arctic Archipelago. At the head of Mercy Bay, northern Banks Island, deglacial mud at the modern coast contains Hiatella arctica and Portlandia arctica bivalves, as well as Cyrtodaria kurriana, previously unreported for this area. Multiple H. arctica and C. kurriana valves from this site yield a mean age of 11.5 14C ka BP (with 740 yr marine reservoir correction). The occurrence of C. kurriana, a low Arctic taxon, raises questions concerning its origin, because evidence is currently lacking for a molluscan refugium in the Arctic Ocean during the last glacial maximum. Elsewhere, the oldest late glacial age available on C. kurriana comes from the Laptev Sea where it is < 10.3 14C ka BP and attributed to a North Atlantic source. This is 2000 cal yr younger than the Mercy Bay samples reported here, making the Laptev Sea, ~ 3000 km to the west, an unlikely source. An alternate route from the North Atlantic into the Canadian Arctic Archipelago was precluded by coalescent Laurentide, Innuitian and Greenland ice east of Banks Island until ~ 10 14C ka BP. We conclude that the presence of C. kurriana on northern Banks Island records migration from the North Pacific. This requires the resubmergence of Bering Strait by 11.5 14C ka BP, extending previous age determinations on the reconnection of the Pacific and Arctic oceans by up to 1000 yr. This renewed ingress of Pacific water likely played an important role in re-establishing Arctic Ocean surface currents, including the evacuation of thick multi-year sea ice into the North Atlantic prior to the Younger Dryas geochron.

  3. Insights into aerosols, chemistry, and clouds from NETCARE: Observations from the Canadian Arctic in summer 2014

    NASA Astrophysics Data System (ADS)

    Abbatt, J.

    2015-12-01

    The Canadian Network on Aerosols and Climate: Addressing Key Uncertainties in Remote Canadian Regions (or NETCARE) was established in 2013 to study the interactions between aerosols, chemistry, clouds and climate. The network brings together Canadian academic and government researchers, along with key international collaborators. Attention is being given to observations and modeling of Arctic aerosol, with the goal to understand underlying processes and so improve predictions of aerosol climate forcing. Motivation to understand the summer Arctic atmosphere comes from the retreat of summer sea ice and associated increase in marine influence. To address these goals, a suite of measurements was conducted from two platforms in summer 2014 in the Canadian Arctic, i.e. an aircraft-based campaign on the Alfred Wegener Institute POLAR 6 and an ocean-based campaign from the CGCS Amundsen icebreaker. NETCARE-POLAR was based out of Resolute Bay, Nunavut during an initial period of little transport and cloud-free conditions and a later period characterized by more transport with potentially biomass burning influence. Measurements included particle and cloud droplet numbers and size distributions, aerosol composition, cloud nuclei, and levels of gaseous tracers. Ultrafine particle events were more frequently observed in the marine boundary layer than above, with particle growth observed in some cases to cloud condensation nucleus sizes. The influence of biological processes on atmospheric constituents was also assessed from the ship during NETCARE-AMUNDSEN, as indicated by high measured levels of gaseous ammonia, DMS and oxygenated VOCs, as well as isolated particle formation and growth episodes. The cruise took place in Baffin Bay and through the Canadian archipelago. Interpretation of the observations from both campaigns is enhanced through the use of chemical transport and particle dispersion models. This talk will provide an overview of NETCARE Arctic observational and

  4. Parasites in grizzly bears from the central Canadian Arctic.

    PubMed

    Gau, R J; Kutz, S; Elkin, B T

    1999-07-01

    Standardized flotation techniques were used to survey 56 grizzly bear (Ursus arctos) fecal samples for parasites. The samples were collected during the spring and autumn of 1995 and 1996 in the central Arctic of the Northwest Territories (Canada). Parasites of the genera Nematodirus, gastrointestinal coccidia, and an unidentified first stage protostrongylid larva are reported for the first time from grizzly bear feces in North America. Parasites of the genera Diphyllobothrium and Baylisascaris also were collected. Prevalence of gastrointestinal parasites were significantly different between the spring and autumn seasons (31% and 58% respectively). Thus, we provide evidence supporting the theory that bears void gastrointestinal parasites before hibernation.

  5. Spatial and temporal trends and effects of contaminants in the Canadian Arctic marine ecosystem: a review.

    PubMed

    Muir, D; Braune, B; DeMarch, B; Norstrom, R; Wagemann, R; Lockhart, L; Hargrave, B; Bright, D; Addison, R; Payne, J; Reimer, K

    1999-06-01

    Recent studies have added substantially to our knowledge of spatial and temporal trends of persistent organic pollutants and heavy metals in the Canadian Arctic marine ecosystem. This paper reviews the current state of knowledge of contaminants in marine biota in the Canadian Arctic and where possible, discusses biological effects. The geographic coverage of information on contaminants such as persistent organochlorines (OCs) (PCBs, DDT- and chlordane-related compounds, hexachlorocyclohexanes, toxaphene) and heavy metals (mercury, selenium, cadmium, lead) in tissues of marine mammal and sea birds is relatively complete. All major beluga, ringed seal and polar bear stocks along with several major sea bird colonies have been sampled and analysed for OC and heavy metal contaminants. Studies on contaminants in walrus are limited to Foxe Basin and northern Québec stocks, while migratory harp seals have only been studied recently at one location. Contaminant measurements in bearded seal, harbour seal, bowhead whale and killer whale tissues from the Canadian Arctic are very limited or non-existent. Many of the temporal trend data for contaminants in Canadian Arctic biota are confounded by changes in analytical methodology, as well as by variability due to age/size, or to dietary and population shifts. Despite this, studies of OCs in ringed seal blubber at Holman Island and in sea birds at Prince Leopold Island in Lancaster Sound show declining concentrations of PCBs and DDT-related compounds from the 1970s to 1980s then a levelling off during the 1980s and early 1990s. For other OCs, such as chlordane, HCH and toxaphene, limited data for the 1980s to early 1990s suggests few significant declines in concentrations in marine mammals or sea birds. Temporal trend studies of heavy metals in ringed seals and beluga found higher mean concentrations of mercury in more recent (1993/1994) samples than in earlier collections (1981-1984 in eastern Arctic, 1972-1973 in western Arctic

  6. Perfluorinated and polyfluorinated compounds in lake food webs from the Canadian high Arctic.

    PubMed

    Lescord, Gretchen L; Kidd, Karen A; De Silva, Amila O; Williamson, Mary; Spencer, Christine; Wang, Xiaowa; Muir, Derek C G

    2015-03-03

    Per- and polyfluorinated alkyl substances (PFASs) enter Arctic lakes through long-range atmospheric transport and local contamination, but their behavior in aquatic food webs at high latitudes is poorly understood. This study compared the concentrations of perfluorocarboxylates, perfluorosulfonates, and fluorotelomer sulfonates (FTS) in biotic and abiotic samples from six high Arctic lakes near Resolute Bay, Nunavut, Canada. Two of these lakes are known to be locally contaminated by a small airport and Arctic char (Salvelinus alpinus) from these lakes had over 100 times higher total [PFAS] when compared to fish from neighboring lakes. Perfluorononanoate (PFOA) and perfluorooctanesulfonate (PFOS) dominated in char, benthic chironomids (their main prey), and sediments, while pelagic zooplankton and water were dominated by lower chain acids and perfluorodecanesulfonate (PFDS). This study also provides the first measures of perfluoroethylcyclohexanesulfonate (PFECHS) and FTS compounds in water, sediment, juvenile char, and benthic invertebrates from lakes in the high Arctic. Negative relationships between [PFAS] and δ(15)N values (indicative of trophic position) within these food webs indicated no biomagnification. Overall, these results suggest that habitat use and local sources of contamination, but not trophic level, are important determinants of [PFAS] in biota from freshwater food webs in the Canadian Arctic.

  7. Imprint of the Pacific Decadal Oscillation on the Western Canadian High-Arctic climate

    NASA Astrophysics Data System (ADS)

    Lapointe, F.; Francus, P.; Lamoureux, S. F.; Vuille, M. F.; Jenny, J. P.; Bradley, R. S.

    2016-12-01

    It is well established that the Arctic strongly influences global climate through positive feedback processes, one of the most effective being the sea-ice - albedo feedback. Understanding the region's sensitivity to both internal and external forcings is thus a prerequisite to better forecast future global climate variations. A recent study has shown that the Pacific Decadal Oscillation (PDO), in its negative phase, greatly contributes to the advection of warm and moist air into the central Arctic, especially during periods of low sea-ice extent (Screen and Francis 2016). Here, sedimentological evidence from an annually laminated (varved) record highlights that the PDO has been a persistent regulator of the regional climate in the western Canadian Arctic. Annual varve thickness from East Lake at Cape Bounty, Melville Island, is negatively correlated with the PDO indexes throughout most of the last 700 years, suggesting drier conditions during high PDO phases, and vice-versa. This is in agreement with known regional teleconnections whereby PDO indexes are negatively and positively correlated with precipitation and mean sea level pressure, respectively. As projected sea-ice loss will contribute to enhanced warming in Arctic regions, future negative phases of the PDO will likely act as amplifiers of this positive feedback. Screen, J. A., and J. A. Francis (2016), Contribution of sea-ice loss to Arctic amplification regulated by Pacific Ocean decadal variability, Nature Clim. Change, 1758-6798.

  8. The influence of declining sea ice on shipping activity in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Pizzolato, Larissa; Howell, Stephen E. L.; Dawson, Jackie; Laliberté, Frédéric; Copland, Luke

    2016-12-01

    Significant attention has focused on the potential for increased shipping activity driven by recently observed declines in Arctic sea ice cover. In this study, we describe the first coupled spatial analysis between shipping activity and sea ice using observations in the Canadian Arctic over the 1990-2015 period. Shipping activity is measured by using known ship locations enhanced with a least cost path algorithm to generate ship tracks and quantified by computing total distance traveled in kilometers. Statistically significant increases in shipping activity are observed in the Hudson Strait (150-500 km traveled yr-1), the Beaufort Sea (40-450 km traveled yr-1), Baffin Bay (50-350 km traveled yr-1), and regions in the southern route of the Northwest Passage (50-250 km traveled yr-1). Increases in shipping activity are significantly correlated with reductions in sea ice concentration (Kendall's tau up to -0.6) in regions of the Beaufort Sea, Western Parry Channel, Western Baffin Bay, and Foxe Basin. Changes in multiyear ice-dominant regions in the Canadian Arctic were found to be more influential on changes to shipping activity compared to seasonal sea ice regions.

  9. Accounts from 19th-century Canadian Arctic explorers' logs reflect present climate conditions

    NASA Astrophysics Data System (ADS)

    Overland, James E.; Wood, Kevin

    The widely perceived failure of 19th-century expeditions to find and transit the Northwest Passage in the Canadian Arctic is often attributed to extraordinary cold climatic conditions associated with the “Little Ice Age” evident in proxy records. However, examination of 44 explorers' logs for the western Arctic from 1818 to 1910 reveals that climate indicators such as navigability, the distribution and thickness of annual sea ice, monthly surface air temperature, and the onset of melt and freeze were within the present range of variability.The quest for the Northwest Passage through the Canadian archipelago during the 19th century is frequently seen as a vain and tragic failure. Polar exploration during the Victorian era seems to us today to have been a costly exercise in heroic futility, which in many respects it was. This perspective has been reinforced since the 1970s, when paleoclimate reconstructions based on Arctic ice core stratigraphy appeared to confirm the existence of exceptionally cold conditions consistent with the period glaciologists had termed the “Little Ice Age” (Figure 1a), with temperatures more than one standard deviation colder relative to an early 20th-century mean [Koerner, 1977; Koerner and Fisher, 1990; Overpeck et al., 1998]. In recent years, the view of the Little Ice Age as a synchronous worldwide and prolonged cold epoch that ended with modern warming has been questioned [Bradley and Jones, 1993; Jones and Briffa, 2001 ;Ogilvie, 2001].

  10. Decadal-Scale Increases in Dissolved Carbon Flux from the Western Canadian Arctic to the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Tank, S. E.; Striegl, R. G.; McClelland, J. W.; Kokelj, S. V.

    2014-12-01

    The chemical signature of large rivers has a clear effect on the chemistry and biology of the nearshore ocean. At the same time, the flux of riverine constituents to coastal environments can be used to understand changes occurring over broad terrestrial landscapes. This is particularly relevant in the Arctic, where rivers have a disproportionate impact on nearshore ocean function. Additionally, change is playing out rapidly in Arctic regions, as permafrost thaw and changes in temperature and hydrology are exposing previously frozen soils, changing the nature of hydrological linkages between land and water, and affecting the seasonality of riverine chemistry and flux. Here, we examine a 40-year dataset of point-measurement alkalinity (largely dissolved inorganic carbon) and dissolved organic carbon (DOC) concentrations near the mouth of the Mackenzie River, in addition to similar data from four of the Mackenzie's major sub-catchments. These datasets are coupled with continuous discharge records, and capture flow from the fourth largest river discharging to the Arctic Ocean. Trends near the Mackenzie mouth show that annual fluxes of both alkalinity and DOC are increasing over time, with the proportional changes in DOC (approximately 16% per decade) being much greater than those for alkalinity (approximately 4% per decade). Seasonally, this increase in total flux occurs largely in the winter and late summer, for both constituents. Sub-catchment datasets indicate that these fluxes are increasing in northern, but not southern, sub-catchment regions. These results have clear implications for nearshore ocean function in the western Canadian Arctic. Increases in DOC may fuel increased bacterial metabolism, while differences in the magnitude of change in alkalinity and DOC flux may modify coastal aragonite saturation. Overall, the changing flux of dissolved carbon near the mouth of the Mackenzie River documents broad-scale changes in the carbon cycle of this region, both on

  11. Circum-Arctic Resource Appraisal: Estimates of Undiscovered Oil and Gas North of the Arctic Circle

    USGS Publications Warehouse

    Bird, Kenneth J.; Charpentier, Ronald R.; Gautier, Donald L.; Houseknecht, David W.; Klett, Timothy R.; Pitman, Janet K.; Moore, Thomas E.; Schenk, Christopher J.; Tennyson, Marilyn E.; Wandrey, Craig R.

    2008-01-01

    The U.S. Geological Survey (USGS) has completed an assessment of undiscovered conventional oil and gas resources in all areas north of the Arctic Circle. Using a geology-based probabilistic methodology, the USGS estimated the occurrence of undiscovered oil and gas in 33 geologic provinces thought to be prospective for petroleum. The sum of the mean estimates for each province indicates that 90 billion barrels of oil, 1,669 trillion cubic feet of natural gas, and 44 billion barrels of natural gas liquids may remain to be found in the Arctic, of which approximately 84 percent is expected to occur in offshore areas.

  12. The Pliocene High Arctic terrestrial palaeoenvironmental record and the development of the western Canadian Arctic coastal plain

    NASA Astrophysics Data System (ADS)

    Rybczynski, N.; Braschi, L.; Gosse, J. C.; Kennedy, C.; Fraser, D.; Lakeman, T.

    2013-12-01

    The Pliocene fossil record of the High Arctic is represented by a collection of sites that occur across the Canadian Arctic Archipelago (CAA), with deposits in the west comprising a 1200 km-long dissected clastic wedge (Beaufort Formation) and those in the east represented by high terrace gravel deposits. Fossil material from these sites is often very well preserved and provides evidence of a boreal-type forest. In the eastern Arctic our research sites includes the Fyles Leaf Bed (FLB) and the Beaver Pond (BP) sites, on west central Ellesmere Island. These are about 10 km apart and preserve evidence of forest and peatlands. The BP fossil site preserves the remains of fossil vertebrates including fish, frog, horse, beaver, deerlet, and black bear, consistent with a boreal type forest habitat. The FLB site has recently yielded the first fossil evidence for a High Arctic camel, identified with the help of collagen fingerprinting from a fragmentary limb bone (tibia). Although modern camels live in open habitats, biogeographic and comparative dental evidence, in combination, suggest that the North American Arctic camels were browsers, and therefore forest-dwelling. Paleoenvironmental reconstruction of the Ellesmere sites has yielded a Mean Annual Temperature of between 14 to 22 degrees Celsius warmer than today. Minimum cosmogenic nuclide burial ages of 3.4 and 3.8 Ma obtained for the BP and FLB sites, respectively, are consistent with vertebrate and floral biostratigraphic evidence. The Beaufort Formation, located in the Western CAA, was formed by a regional northwesterly flowing braided fluvial system. The Beaufort Formation appears to have filled at least the western portions of the 100 km-wide channels that currently separate the islands of the CAA. Intervals of Pliocene continental-shelf progradation are recorded in the lower Iperk Formation, which is situated offshore and includes complex sigmoid-oblique clinoforms indicative of high-energy, coarse

  13. Assessment of undiscovered oil and gas in the arctic

    USGS Publications Warehouse

    Gautier, D.L.; Bird, K.J.; Charpentier, R.R.; Grantz, A.; Houseknecht, D.W.; Klett, T.R.; Moore, T.E.; Pitman, J.K.; Schenk, C.J.; Schuenemeyer, J.H.; Sorensen, K.; Tennyson, M.E.; Valin, Z.C.; Wandrey, C.J.

    2009-01-01

    Among the greatest uncertainties in future energy supply and a subject of considerable environmental concern is the amount of oil and gas yet to be found in the Arctic. By using a probabilistic geologybased methodology, the United States Geological Survey has assessed the area north of the Arctic Circle and concluded that about 30% of the world's undiscovered gas and 13% of the world's undiscovered oil may be found there, mostly offshore under less than 500 meters of water. Undiscovered natural gas is three times more abundant than oil in the Arctic and is largely concentrated in Russia. Oil resources, although important to the interests of Arctic countries, are probably not sufficient to substantially shift the current geographic pattern of world oil production.

  14. Assessment of undiscovered oil and gas in the Arctic.

    PubMed

    Gautier, Donald L; Bird, Kenneth J; Charpentier, Ronald R; Grantz, Arthur; Houseknecht, David W; Klett, Timothy R; Moore, Thomas E; Pitman, Janet K; Schenk, Christopher J; Schuenemeyer, John H; Sørensen, Kai; Tennyson, Marilyn E; Valin, Zenon C; Wandrey, Craig J

    2009-05-29

    Among the greatest uncertainties in future energy supply and a subject of considerable environmental concern is the amount of oil and gas yet to be found in the Arctic. By using a probabilistic geology-based methodology, the United States Geological Survey has assessed the area north of the Arctic Circle and concluded that about 30% of the world's undiscovered gas and 13% of the world's undiscovered oil may be found there, mostly offshore under less than 500 meters of water. Undiscovered natural gas is three times more abundant than oil in the Arctic and is largely concentrated in Russia. Oil resources, although important to the interests of Arctic countries, are probably not sufficient to substantially shift the current geographic pattern of world oil production.

  15. Regional Modelling of Air Quality in the Canadian Arctic: Impact of marine shipping and North American wild fire emissions

    NASA Astrophysics Data System (ADS)

    Gong, W.; Beagley, S. R.; Zhang, J.; Cousineau, S.; Sassi, M.; Munoz-Alpizar, R.; Racine, J.; Menard, S.; Chen, J.

    2015-12-01

    Arctic atmospheric composition is strongly influenced by long-range transport from mid-latitudes as well as processes occurring in the Arctic locally. Using an on-line air quality prediction model GEM-MACH, simulations were carried out for the 2010 northern shipping season (April - October) over a regional Arctic domain. North American wildfire emissions and Arctic shipping emissions were represented, along with other anthropogenic and biogenic emissions. Sensitivity studies were carried out to investigate the principal sources and processes affecting air quality in the Canadian Northern and Arctic regions. In this paper, we present an analysis of sources, transport, and removal processes on the ambient concentrations and atmospheric loading of various pollutants with air quality and climate implications, such as, O3, NOx, SO2, CO, and aerosols (sulfate, black carbon, and organic carbon components). Preliminary results from a model simulation of a recent summertime Arctic field campaign will also be presented.

  16. The Endangered Arctic, the Arctic as Resource Frontier: Canadian News Media Narratives of Climate Change and the North.

    PubMed

    Stoddart, Mark C J; Smith, Jillian

    2016-08-01

    The Arctic is one of the most radically altered parts of the world due to climate change, with significant social and cultural impacts as a result. Using discourse network analysis and qualitative textual analysis of articles published in the Globe and Mail and National Post during the period 2006 to 2010, we identify and analyze key frames that interpret the implications of climate change on the Arctic. We examine Canadian national news media coverage to ask: How does the Arctic enter media coverage of climate change? Is there evidence of a climate justice discourse in relation to regional disparities in the risks and harms of climate change between northern and southern Canada? Climate change in the Arctic is often framed through the lens of Canadian national interests, which downplays climate-related social impacts that are already occurring at subnational political and geographical scales. L'Arctique est une des régions du monde la plus radicalement altérée par le changement climatique, menant comme résultat des importants changements sociaux et culturels. En utilisant l'analyse des réseaux de discours ainsi que l'analyse textuelle qualitative des articles publiés dans le Globe and Mail et le National Post de 2006 à 2010, nous identifions and analysons des cadres clés qui servent à interpréter les conséquences du changement climatique dans l'Arctique. Nous examinons la couverture des médias nationaux canadiens pour pouvoir demander : comment est-ce que l'Arctique s'insère dans la couverture médiatique du changement climatique? Est-ce qu'il y a de la preuve d'un discours de la justice climatique en relation des disparités régionales des risques et méfaits du changement climatique entre le Canada du nord et du sud? Le changement climatique dans l'Arctique est souvent encadré à travers le prisme des intérêts nationaux canadiens, ce qui minimise les impacts sociaux reliés au climat qui se produisent actuellement aux échelons sous

  17. The Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Project: Overview and results from ten years of ACE operations

    NASA Astrophysics Data System (ADS)

    Walker, Kaley; Strong, Kimberly

    2014-05-01

    As of February 2014, the Canadian-led Atmospheric Chemistry Experiment (ACE) satellite mission has been making measurements of the Earth's atmosphere for ten years. As ACE operations have extended beyond the initial two-year mission, there is a continuing need to validate the trace gas data products from the ACE-Fourier Transform Spectrometer (ACE-FTS) and the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO) instruments. Ground-based measurements provide critical data for the validation of satellite retrievals of trace gases and for the assessment of long-term stability of these measurements. In particular, validation comparisons are needed for ACE during Arctic springtime to understand better the measurements of species involved in stratospheric ozone chemistry. To this end, eleven Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns have been conducted during the spring period (February - April in 2004 - 2014) at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Nunavut (80°N, 86°W). This period coincides with the most chemically active time of year in the Arctic, as well as a significant number of satellite overpasses. A suite of as many as 12 ground-based instruments, as well as frequent balloon-borne ozonesonde and radiosonde launches, have been used in each campaign. These instruments include: a ground-based version of the ACE-FTS (PARIS - Portable Atmospheric Research Interferometric Spectrometer), a terrestrial version of the ACE-MAESTRO, a SunPhotoSpectrometer, two zenith-viewing UV-visible grating spectrometers, a Bomem DA8 Fourier transform spectrometer, a Bruker 125HR Fourier transform spectrometer, a Systeme d'Analyse par Observations Zenithales (SAOZ) instrument, and several Brewer spectrophotometers. In the past several years, these results have been used to validate the measurements by the ACE-FTS and ACE-MAESTRO instruments on SCISAT as well

  18. Canadian Basin freshwater sources and changes: Results from the 2005 Arctic Ocean Section

    NASA Astrophysics Data System (ADS)

    Newton, Robert; Schlosser, Peter; Mortlock, Richard; Swift, James; MacDonald, Robie

    2013-04-01

    We present measurements of oxygen isotope ratios and nutrient concentrations along the 2005 Arctic Ocean Section aboard the icebreaker Oden. The data are used to estimate freshwater contributions from meteoric water (mainly river runoff), sea-ice meltwater, and Chukchi Sea shelf water, itself a combination of Pacific and indigenous Arctic water types. Nutrients ratios are combined to form quasi-conservative water-mass tracers (phosphate-star, N-star, and the empirical Arctic N-P relationship) and used along with salinity and δ18O, which are conservative in the ocean interior. Disagreements between two different freshwater analyses in the Western Arctic are largely resolved using a salinity-dependent Redfield ratio, a new estimate of the Pacific end-member, and an analysis of the Bering Strait inflow contribution to detraining shelf waters. Freshwater components from 2005 are placed into the context of the overlapping 1994 Arctic Ocean Section (aboard the Louis St. Laurent) and a time series of hydrographic/tracer casts between 1987 and 1992 in the Canada Basin. Compared to 1987-1994; the 2005 transect exhibits increased meteoric water concentrations in the northern part of the Canadian Basin and a decrease in the southern part. This pattern is related to changes in the distribution of wind-stress curl during the several years prior to each sampling campaign. In addition, a previously observed correlation between sea-ice formation and river runoff disappears over the Central Arctic in 2005, a change that we attribute to a northward shift of sea-ice formation. Resampling approximately every 3 years should resolve the dynamics driving changes in freshwater and nutrient distributions.

  19. Trophodynamics of some PFCs and BFRs in a western Canadian Arctic marine food web.

    PubMed

    Tomy, Gregg T; Pleskach, Kerri; Ferguson, Steve H; Hare, Jonathon; Stern, Gary; Macinnis, Gordia; Marvin, Chris H; Loseto, Lisa

    2009-06-01

    The trophodynamics of per- and polyfluorinated compounds and bromine-based flame retardants were examined in components of a marine food web from the western Canadian Arctic. The animals studied and their relative trophic status in the food web, established using stable isotopes of nitrogen (delta15N), were beluga (Delphinapterus leucas) > ringed seal (Phoca hispida) > Arctic cod (Boreogadus saida) > Pacific herring (Clupea pallasi) approximately equal to Arctic cisco (Coregonus autumnalis) > pelagic amphipod (Themisto libellula) > Arctic copepod (Calanus hyperboreus). For the brominated diphenyl ethers, the lipid adjusted concentrations of the seven congeners analyzed (Sigma7BDEs: -47, -85, -99, -100, -153, -154, and -209) ranged from 205.4 +/- 52.7 ng/g in Arctic cod to 2.6 +/- 0.4 ng/g in ringed seals. Mean Sigma7BDEs concentrations in Arctic copepods, 16.4 ng/g (n = 2, composite sample), were greater than those in the top trophic level (TL) marine mammals and suggests that (i) Arctic copepods are an important dietary component that delivers BDEs to the food web and (ii) because these compounds are bioaccumulative, metabolism and depletion of BDE congeners in top TL mammals is an important biological process. There were differences in the concentration profiles of the isomers of hexabromocyclododecane (HBCD) in the food web. The most notable difference was observed for beluga, where the alpha-isomer was enriched (accounting for approximately 90% of the SigmaHBCD body burden), relative to its primary prey species, Arctic cod, where the alpha-isomer accounted for only 20% of the SigmaHBCD body burden (beta: 4% and gamma: 78%). For the C8-C11 perfluorinated carboxylic acids, the trophic magnification factors (TMFs) were all greater than unity and increased with increasing carbon chain length. PFOS and its neutral precursor, PFOSA, also had TMF values greater than one. There were also pronounced differences in the PFOSA to PFOS ratio in ringed seal (0.04) and in

  20. Archives of total mercury reconstructed with ice and snow from Greenland and the Canadian High Arctic.

    PubMed

    Zheng, Jiancheng

    2015-03-15

    This study reports total Hg concentration and atmospheric flux data from ice cores and snow/ice shallow pits from two Canadian Arctic and one Greenland glaciers, with the aim of reconstructing a high resolution record of THg deposition extending back into the pre-industrial period. An 88-m ice core (653 samples) from the NEEM glacier site in Northwest Greenland was retrieved in August 2010. The bottom sample was dated to 1748, resulting in a 262 year archive. Snow and ice samples (143 samples) were recovered from a 10.3-m pit dug on the Mt. Oxford Icefield, Nunavut, in May 2008, covering 30 years. Another 15.5-m short core drilled on the Agassiz Ice Cap, Nunavut, in April 2009 yielded 191 samples covering 74 years. Net rates of atmospheric THg deposition (FTHg) were calculated based on THg concentrations and snow accumulation rates. Results from NEEM site show that THg and FTHg range from sub-pg g(-1) to 120.6 pg g(-1) (mean=1.5 pg g(-1), n=653) and from 0.06 to 1.42 μg m(-2) year(-1) (mean=0.25 μg m(-2) year(-1), n=218) respectively, much lower than those found in other natural media such as sediments, peat bogs and wet precipitation. The discrepancy of FTHg found in glaciers from other natural media could mainly be due to the more severe photo-reduction and reemission of deposited oxidized Hg. This study also demonstrates that reproducible THg archives can be reconstructed with glacier ice and snow samples from Greenland and the Canadian High Arctic. The THg archive reconstructed with the short core from NEEM site is so far the longest with the highest resolution in Greenland and the Canadian High Arctic.

  1. Long-term decrease of cadmium concentrations in the Canadian Arctic air

    NASA Astrophysics Data System (ADS)

    Li, Chunsheng; Cornett, Jack; Ungar, Kurt

    2003-03-01

    Average cadmium concentrations in the air (particulate samples) at two Canadian Arctic sites, Resolute (74.7°N, 95.0°W) and Coral Harbor (64.2°N, 83.3°W) declined from about 0.2 ng m-3 to about 0.05 ng m-3 between the early 1970s and 2000. Cadmium concentrations in the air at southern Canada sites were much higher (0.05-1.12 ng m-3) than those measured in the Arctic. The concentrations of cadmium measured at all sites decreased by a factor of three to seven between 1973 and 2000. This decrease correlates with the reduction in anthropogenic emissions from the production of non-ferrous metals following the introduction of emission control technologies.

  2. Decline of hexachlorocyclohexane in the Arctic atmosphere and reversal of air-sea gas exchange

    NASA Astrophysics Data System (ADS)

    Bidleman, T. F.; Jantunen, L. M.; Falconer, R. L.; Barrie, L. A.; Fellin, P.

    1995-02-01

    Hexachlorocyclohexanes (HCHs) are the most abundant organochlorine pesticides in the arctic atmosphere and ocean surface water. A compilation of measurements made between 1979-93 from stations in the Canadian and Norwegian Arctic and from cruises in the Bering and Chukchi seas indicates that atmospheric concentrations of α-HCH have declined significantly (p < 0.01), with a time for 50% decrease of about 4 y in summer-fall and 6 y in winter-spring. The 1992-93 levels of about 100 pg m-3 are 2-4 fold lower than values in the mid-1980s. The trend in γ-HCH is less pronounced, but a decrease is also suggested from measurements in the Canadian Arctic and the Bering-Chukchi seas. HCHs in ocean surface water have remained relatively constant since the early 1980s. The decline in atmospheric α-HCH has reversed the net direction of air-sea gas exchange to the point where some northern waters are now sources of the pesticide to the atmosphere instead of sinks.

  3. The effect of snow cover on lemming population cycles in the Canadian high Arctic.

    PubMed

    Bilodeau, Frédéric; Gauthier, Gilles; Berteaux, Dominique

    2013-08-01

    Rising temperatures and changes in the precipitation regime will have a strong impact on the quality of the snow cover in the Arctic. A snow cover of good quality protecting lemmings from cold temperatures and predators is thought to be an important factor for maintaining the cyclic dynamic of their populations in the tundra. We examined if the characteristics of annual fluctuations (amplitude and shape of phases) in brown lemming (Lemmus trimucronatus) density could be determined by snow depth, snow density, sub-nivean temperature and persistence of snow. Using an 18-year time series of brown lemming abundance on Bylot Island in the Canadian Arctic, we tested if snow variables could explain the residual variation between the observed lemming density and the one predicted by models where cyclicity had been accounted for. Our analysis provides support for the hypothesis that snow cover can affect the amplitude and possibly also the periodicity of lemming population cycles in the High Arctic. Summer abundance of brown lemmings was higher following winters with a deep snow cover and a low-density snow pack near the ground but was unaffected by the date of establishment or melting and duration of the snow cover. Two snow variables showed a temporal trend; mean winter snow depth tended to increase and date of establishment of the hiemal threshold occurred earlier over time. These temporal trends, which should be favourable to lemmings, may explain why healthy population cycles have apparently been maintained at our study site contrary to other Arctic sites.

  4. Source-receptor relationship: A case study of the origin of Canadian High Arctic air masses

    NASA Astrophysics Data System (ADS)

    Damoah, R.; Bacak, A.; Kuhn, T.; Sloan, J. J.

    2009-05-01

    In summer 2006 measurements at the Polar Environment Atmospheric Research Laboratory (PEARL) located in the Canadian Arctic (80oN, 86oW) observed episodes of high pollutants (sulphate, organic). We have used trajectory and particle dispersion models FLEXTRA and FLEXPART to study the relationship between the air mass arriving at PEARL within the episode period and the contributing sources, as well as the long-range transport pattern. FLEXPART is a Lagrangian particle dispersion model that simulates the long-range transport, diffusion, dry and wet deposition, and radioactive decay of tracers released from point, line, area or volume sources. Backward simulations of both FLEXTRA and FLEXPART indicate that between September 1 and September 4 (one of the episodes) there was substantial contribution from Norilsk, Northern Russia. In fact, The air mass from Norilsk travelled northwards through Chelyuskin, crossed the Arctic Sea and proceeded towards PEARL. Most of the transport was limited to the Arctic (> 80 ) and at low altitude (< 4 km asl). The total time travelled by the air mass from Norilsk was between 10-20 days. Further analysis is required in order to quantify the regional contributions to these Arctic episodes.

  5. Integrating terrestrial and marine archives of Late Wisconsinan ice stream dynamics in the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Lakeman, Thomas; Blasco, Steve; MacLean, Brian; Bennett, Robbie; England, John; Hughes Clarke, John; Covill, Bob; Patton, Eric

    2014-05-01

    During Late Wisconsinan glaciation the northern Laurentide and Innuitian ice sheets converged over the Canadian Arctic Archipelago. This ice sheet complex included several major ice streams, which constituted important dynamical components. Discharging into the Beaufort Sea and Baffin Bay, these ice streams were a primary control on ice sheet mass balance and ice age sedimentation on adjacent continental margins, including the Arctic Ocean basin. This study presents a new compilation of multibeam echosounder data, sub-bottom profiler data, radiocarbon ages, and marine sediment cores acquired primarily during regional surveys with the CCGS Amundsen. These data characterize the nature and thickness of seafloor sediments in Parry Channel (and many of its connecting channels) and Amundsen Gulf. When combined with the results of terrestrial geomorphological mapping of the adjacent islands, this dataset constrains the maximum extent, chronology, and behaviour of former ice streams in M'Clure Strait, Viscount Melville Sound, Lancaster Sound, and Amundsen Gulf. Importantly, these data highlight complex patterns of past ice stream flow during regional deglaciation. These results contribute to a better understanding of the causal mechanisms that occasioned retreat of the terrestrial and marine sectors of the Laurentide and Innuitian ice sheets. As well, this study helps to quantify past iceberg fluxes to the Arctic Ocean, which has implications for assessing past climate, and the origin of ice-rafted sediment and deep iceberg scours in the Arctic Ocean basin.

  6. Local cultural animal food contributes high levels of nutrients for Arctic Canadian Indigenous adults and children.

    PubMed

    Kuhnlein, Harriet V; Receveur, Olivier

    2007-04-01

    Food systems of Canadian Arctic Indigenous Peoples contain many species of traditional animal and plant food, but the extent of use today is limited because purchased food displaces much of the traditional species from the diet. Frequency and 24-h dietary interviews of Arctic adults and children were used to investigate these trends. The most frequently consumed Arctic foods were derived from animals and fish. In adults these foods contributed 6-40% of daily energy of adults. Children ate much less, 0.4-15% of energy, and >40% of their total energy was contributed by "sweet" and "fat" food sources. Nevertheless, for adults and children, even a single portion of local animal or fish food resulted in increased (P < 0.05) levels of energy, protein, vitamin D, vitamin E, riboflavin, vitamin B-6, iron, zinc, copper, magnesium, manganese, phosphorus, and potassium; although children had similar results for these nutrients, they did not reach significance for energy, vitamin D, or manganese. Because market foods are the major source of energy in the Arctic, traditional animal-source foods are extremely important to ensure high dietary quality of both adults and children.

  7. Prevalence of diabetes mellitus and obesity in the Keewatin District of the Canadian Arctic.

    PubMed

    Orr, P H; Martin, B D; Patterson, K; Moffatt, M E

    1998-01-01

    Through a medical chart review, the prevalence of diagnosed diabetes mellitus in Inuit of the Keewatin District of the Canadian Northwest Territories was determined to be 0.27%. All cases were in adults, and no cases of gestational diabetes were noted. The prevalence and pattern of obesity were determined from measurements of body mass index (BMI), skinfold thickness, and waist-hip ratio obtained during the 1990-91 Keewatin Health Assessment Study. Thirty-one percent of 414 randomly identified adults (29% of men, 37% of women) were overweight (BMI > 27). Central fat patterning was more prevalent in women and less prevalent in men from the Keewatin compared to the general Canadian population. Comparison of skinfold thickness values to published measurements obtained from earlier arctic surveys supports the hypothesis that changes in diet and activity levels associated with urbanization have resulted in increased obesity in the Inuit.

  8. Dissolved organic matter photolysis in Canadian arctic thaw ponds

    NASA Astrophysics Data System (ADS)

    Laurion, Isabelle; Mladenov, Natalie

    2013-09-01

    The abundant thaw lakes and ponds in the circumarctic receive a new pool of organic carbon as permafrost peat soils degrade, which can be exposed to significant irradiance that potentially increases as climate warms and ice cover shortens. Exposure to sunlight is known to accelerate the transformation of dissolved organic matter (DOM) into molecules that can be more readily used by microbes. We sampled the water from two common classes of ponds found in the ice-wedge system of continuous permafrost regions of Canada, polygonal and runnel ponds, and followed the transformation of DOM over 12 days by looking at dissolved organic carbon (DOC) concentration and DOM absorption and fluorescence properties. The results indicate a relatively fast decay of color (3.4 and 1.6% loss d-1 of absorption at 320 nm for the polygonal and runnel pond, respectively) and fluorescence (6.1 and 8.3% loss d-1 of total fluorescent components, respectively) at the pond surface, faster in the case of humic-like components, but insignificant losses of DOC over the observed period. This result indicates that direct DOM mineralization (photochemical production of CO2) is apparently minor in thaw ponds compared to the photochemical transformation of DOM into less chromophoric and likely more labile molecules with a greater potential for microbial mineralization. Therefore, DOM photolysis in arctic thaw ponds can be considered as a catalytic mechanism, accelerating the microbial turnover of mobilized organic matter from thawing permafrost and the production of greenhouse gases, especially in the most shallow ponds. Under a warming climate, this mechanism will intensify as summers lengthen.

  9. Otitis media in Inuit children in the Eastern Canadian Arctic--an overview--1968 to date.

    PubMed

    Baxter, J D

    1999-10-05

    Clinical observations made on the Inuit in the Eastern Canadian Arctic during the past three decades support that the current high prevalence of chronic otitis media among their children is a relatively new phenomenon. It is a social/economic disease related to their urbanization that occurred following World War II when the vast majority of the Inuit abandoned their isolated nomadic way of life and moved into permanent settlements. The disease, in a great many, runs a natural course with spontaneous healing. There is evidence that as the new millennium approaches the prevalence of the disease among the children is decreasing.

  10. Polynya Formation, Location, Sea Level History and Human Settlement in the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Schledermann, P.; Murray, M. S.; Hannah, C. G.

    2014-12-01

    In this paper we illustrate the relationship between polynya location and archaeological site distribution in the Canadian Arctic archipelago. Polynyas in this region may be tidally driven or latent heat polynyas and Holocene-ere human settlement in some regions appears to be strongly correlated with polynya location and possibly type. Changes in sea level may also have affected the size, location and type of polynya and may explain, in part, why some regions experienced fluctuations in settlement density at various times in the Holocene. Past changes in sea level and climate may serve as predictors of future change in polynya formation with concurrent implications for ecological productivity.

  11. Ice-nucleating particles in Canadian Arctic sea-surface microlayer and bulk seawater

    NASA Astrophysics Data System (ADS)

    Irish, Victoria E.; Elizondo, Pablo; Chen, Jessie; Chou, Cédric; Charette, Joannie; Lizotte, Martine; Ladino, Luis A.; Wilson, Theodore W.; Gosselin, Michel; Murray, Benjamin J.; Polishchuk, Elena; Abbatt, Jonathan P. D.; Miller, Lisa A.; Bertram, Allan K.

    2017-09-01

    The sea-surface microlayer and bulk seawater can contain ice-nucleating particles (INPs) and these INPs can be emitted into the atmosphere. Our current understanding of the properties, concentrations, and spatial and temporal distributions of INPs in the microlayer and bulk seawater is limited. In this study we investigate the concentrations and properties of INPs in microlayer and bulk seawater samples collected in the Canadian Arctic during the summer of 2014. INPs were ubiquitous in the microlayer and bulk seawater with freezing temperatures in the immersion mode as high as -14 °C. A strong negative correlation (R = -0. 7, p = 0. 02) was observed between salinity and freezing temperatures (after correction for freezing depression by the salts). One possible explanation is that INPs were associated with melting sea ice. Heat and filtration treatments of the samples show that the INPs were likely heat-labile biological materials with sizes between 0.02 and 0.2 µm in diameter, consistent with previous measurements off the coast of North America and near Greenland in the Arctic. The concentrations of INPs in the microlayer and bulk seawater were consistent with previous measurements at several other locations off the coast of North America. However, our average microlayer concentration was lower than previous observations made near Greenland in the Arctic. This difference could not be explained by chlorophyll a concentrations derived from satellite measurements. In addition, previous studies found significant INP enrichment in the microlayer, relative to bulk seawater, which we did not observe in this study. While further studies are needed to understand these differences, we confirm that there is a source of INP in the microlayer and bulk seawater in the Canadian Arctic that may be important for atmospheric INP concentrations.

  12. A regional-scale estimation of ice wedge ice volumes in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Templeton, M.; Pollard, W. H.; Grand'Maison, C. B.

    2016-12-01

    Ice wedges are both prominent and environmentally vulnerable features in continuous permafrost environments. As the world's Arctic regions begin to warm, concern over the potential effects of ice wedge melt out has become an immediate issue, receiving much attention in the permafrost literature. In this study we estimate the volume of ice wedge ice for large areas in the Canadian High Arctic through the use of high resolution satellite imagery and the improved capabilities of Geographic Information Systems (GIS). The methodology used for this study is similar to that of one performed in Siberia and Alaska by Ulrich et al, in 2014. Utilizing Ulrich's technique, this study detected ice wedge polygons from satellite imagery using ArcGIS. The average width and depth of these ice wedges were obtained from a combination of field data and long-term field studies for the same location. The assumptions used in the analysis of ice wedge volume have been tested, including trough width being representative of ice wedge width, and ice wedge ice content (Pollard and French 1980). This study used specific field sites located near Eureka on Ellesmere Island (N80°01', W85°43') and at Expedition Fiord on Axel Heiberg Island (N79°23', W90°59'). The preliminary results indicate that the methodology used by Ulrich et al, 2014 is transferrable to the Canadian High Arctic, and that ice wedge volumes range between 3-10% of the upper part of permafrost. These findings are similar to previous studies and their importance is made all the more evident by the dynamic nature of ice wedges where it could be argued that they are a key driver of thermokarst terrain. The ubiquitous nature of ice wedges across arctic terrain highlights the importance and the need to improve our understanding of ice wedge dynamics, as subsidence from ice wedge melt-out could lead to large scale landscape change.

  13. Spatial and temporal trends of contaminants in Canadian Arctic freshwater and terrestrial ecosystems: a review.

    PubMed

    Braune, B; Muir, D; DeMarch, B; Gamberg, M; Poole, K; Currie, R; Dodd, M; Duschenko, W; Eamer, J; Elkin, B; Evans, M; Grundy, S; Hebert, C; Johnstone, R; Kidd, K; Koenig, B; Lockhart, L; Marshall, H; Reimer, K; Sanderson, J; Shutt, L

    1999-06-01

    The state of knowledge of contaminants in Canadian Arctic biota of the freshwater and terrestrial ecosystems has advanced enormously since the publication of the first major reviews by Lockhart et al. and Thomas et al. in The Science of the Total Environment in 1992. The most significant gains are new knowledge of spatial trends of organochlorines and heavy metal contaminants in terrestrial animals, such as caribou and mink, and in waterfowl, where no information was previously available. Spatial trends in freshwater fish have been broadened, especially in the Yukon, where contaminant measurements of, for example, organochlorines were previously non-existent. A review of contaminants data for fish from the Northwest Territories, Yukon and northern Quebec showed mercury as the one contaminant which consistently exceeds guideline limits for subsistence consumption or commercial sale. Lake trout and northern pike in the Canadian Shield lakes of the Northwest Territories and northern Quebec generally had the most elevated levels. Levels of other heavy metals were generally not elevated in fish. Toxaphene was the major organochlorine contaminant in all fish analyzed. The concentrations of organochlorine contaminants in fish appear to be a function not only of trophic level but of other aspects of the lake ecosystem. Among Arctic terrestrial mammals, PCBs and cadmium were the most prominent contaminants in the species analyzed. Relatively high levels (10-60 micrograms g-1) of cadmium were observed in kidney and liver of caribou from the Yukon, the Northwest Territories and northern Quebec, with concentrations in western herds being higher than in those from the east. For the organochlorine contaminants, a west to east increase in zigma PCBs, HCB and zigma HCH was found in caribou, probably as a result of the predominant west to east/north-east atmospheric circulation pattern which delivers these contaminants from industrialized regions of central and eastern North

  14. A Large Eddy Simulation Study of Heat Entrainment under Sea Ice in the Canadian Arctic Basin

    NASA Astrophysics Data System (ADS)

    Ramudu, E.; Yang, D.; Gelderloos, R.; Meneveau, C. V.; Gnanadesikan, A.

    2016-12-01

    Sea ice cover in the Arctic has declined rapidly in recent decades. The much faster than projected retreat suggests that climate models may be missing some key processes, or that these processes are not accurately represented. The entrainment of heat from the mixed layer by small-scale turbulence is one such process. In the Canadian Basin of the Arctic Ocean, relatively warm Pacific Summer Water (PSW) resides at the base of the mixed layer. With an increasing influx of PSW, the upper ocean in the Canadian Basin has been getting warmer and fresher since the early 2000s. While studies show a correlation between sea ice reduction and an increase in PSW temperature, others argue that PSW intrusions in the Canadian Basin cannot affect sea ice thickness because the strongly-stratified halocline prevents heat from the PSW layer from being entrained into the mixed layer and up to the basal ice surface. In this study, we try to resolve this conundrum by simulating the turbulent entrainment of heat from the PSW layer to a moving basal ice surface using large eddy simulation (LES). The LES model is based on a high-fidelity spectral approach on horizontal planes, and includes a Lagrangian dynamic subgrid model that reduces the need for empirical inputs for subgrid-scale viscosities and diffusivities. This LES tool allows us to investigate physical processes in the mixed layer at a very fine scale. We focus our study on summer conditions, when ice is melting, and show for a range of ice-drift velocities, halocline temperatures, and halocline salinity gradients characteristic of the Canadian Basin how much heat can be entrained from the PSW layer to the sea ice. Our results can be used to improve parameterizations of vertical heat flux under sea ice in coarse-grid ocean and climate models.

  15. Transport Regimes of Air Masses Affecting the Tropospheric Composition of the Canadian and European Arctic During RACEPAC 2014 and NETCARE 2014/2015

    NASA Astrophysics Data System (ADS)

    Bozem, H.; Hoor, P. M.; Koellner, F.; Kunkel, D.; Schneider, J.; Schulz, C.; Herber, A. B.; Borrmann, S.; Wendisch, M.; Ehrlich, A.; Leaitch, W. R.; Willis, M. D.; Burkart, J.; Thomas, J. L.; Abbatt, J.

    2015-12-01

    The Arctic is warming much faster than any other place in the world and undergoes a rapid change dominated by a changing climate in this region. The impact of polluted air masses traveling to the Arctic from various remote sources significantly contributes to the observed climate change, in contrast there are additional local emission sources contributing to the level of pollutants (trace gases and aerosol). Processes affecting the emission and transport of these pollutants are not well understood and need to be further investigated. We present aircraft based trace gas measurements in the Arctic during RACEPAC (2014) and NETCARE (2014 and 2015) with the Polar 6 aircraft of Alfred Wegener Institute (AWI) covering an area from 134°W to 17°W and 68°N to 83°N. We focus on cloud, aerosol and general transport processes of polluted air masses into the high Arctic. Based on CO and CO2 measurements and kinematic 10-day back trajectories we analyze the transport regimes prevalent during spring (RACEPAC 2014 and NETCARE 2015) and summer (NETCARE 2014) in the observed region. Whereas the eastern part of the Canadian Arctic is affected by air masses with their origin in Asia, in the central and western parts of the Canadian and European Arctic air masses from North America are predominant at the time of the measurement. In general the more northern parts of the Arctic were relatively unaffected by pollution from mid-latitudes since air masses mostly travel within the polar dome, being quite isolated. Associated mixing ratios of CO and CO2 fit into the seasonal cycle observed at NOAA ground stations throughout the Arctic, but show a more mid-latitudinal characteristic at higher altitudes. The transition is remarkably sharp and allows for a chemical definition of the polar dome. At low altitudes, synoptic disturbances transport polluted air masses from mid-latitudes into regions of the polar dome. These air masses contribute to the Arctic pollution background, but also

  16. Medical Encounters During a Joint Canadian/U.S. Exercise in the High Arctic (Exercise Arctic Ram).

    PubMed

    Sullivan-Kwantes, Wendy; Dhillon, Paul; Goodman, Len; Knapik, Joseph J

    2017-09-01

    The Arctic Ram Exercise was conducted in February 2016, near Resolute Bay on Cornwallis Island in Nunavut, Canada, to demonstrate the ability of the Canadian Armed Forces (CAF) to rapidly deploy to the arctic as an immediate response team. This report describes medical problems experienced by the 187 CAF and 28 U.S. forces involved in the exercise. Sixty-six airborne soldiers performed tactical static line jumps and linked up with soldiers on the ground for the exercise. Medical events were recorded by medics on the drop zone and by medical personnel at the Unit Medical Station in Resolute Bay. Average temperature during the exercise was -21°C and wind chill was -44°C. Two U.S. soldiers were injured in association with the jump and an additional 62 patients presented at the clinic during the exercise for an overall medical event incidence of 30%. The incidence of frostbite was 17%. At the end of the exercise, a physician actively examined CAF soldiers in one unit (n = 126) and found that 21% had experienced frostbite. The incidence of frostbite was high in this exercise compared to past cold-weather military operations, likely related to the very low temperatures and wind chills. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

  17. Modern to millennium-old greenhouse gases emitted from ponds and lakes of the Eastern Canadian Arctic (Bylot Island, Nunavut)

    NASA Astrophysics Data System (ADS)

    Bouchard, F.; Laurion, I.; Prėskienis, V.; Fortier, D.; Xu, X.; Whiticar, M. J.

    2015-12-01

    Ponds and lakes are widespread across the rapidly changing permafrost environments. Aquatic systems play an important role in global biogeochemical cycles, especially in greenhouse gas (GHG) exchanges between terrestrial systems and the atmosphere. The source, speciation and emission rate of carbon released from permafrost landscapes are strongly influenced by local conditions, hindering pan-Arctic generalizations. This study reports on GHG ages and emission rates from aquatic systems located on Bylot Island, in the continuous permafrost zone of the Eastern Canadian Arctic. Dissolved and ebullition gas samples were collected during the summer season from different types of water bodies located in a highly dynamic periglacial valley: polygonal ponds, collapsed ice-wedge trough ponds, and larger lakes. The results showed strikingly different ages and fluxes depending on aquatic system types. Polygonal ponds were net sinks of dissolved CO2, but variable sources of dissolved CH4. They presented the highest ebullition fluxes, 1 or 2 orders of magnitude higher than from other ponds and lakes. Trough ponds appeared as substantial GHG sources, especially when their edges were actively eroding. Both types of ponds produced modern to hundreds of years old (< 550 yr BP) GHG, even if trough ponds could contain much older carbon (> 2000 yr BP) derived from freshly eroded peat. Lakes had small dissolved and ebullition fluxes, however they released much older GHG, including millennium-old CH4 (up to 3500 yr BP) from lake central areas. Acetoclastic methanogenesis dominated at all study sites and there was minimal, if any, methane oxidation in gas emitted through ebullition. These findings provide new insights on GHG emissions by permafrost aquatic systems and their potential positive feedback effect on climate.

  18. Unexpectedly high radioactivity burdens in ice-rafted sediments from the Canadian Arctic Archipelago.

    PubMed

    Cota, Glenn F; Cooper, Lee W; Darby, Dennis A; Larsen, I L

    2006-07-31

    Unexpectedly high specific activities of (137)Cs (1800-2000 Bq kg(-1) dry weight) have been detected in fine-grained sediments entrained in multi-year sea ice floes grounded in Resolute Bay near the center of the Northwest Passage through the Canadian Arctic Archipelago. These results are remarkable because: (1) the specific activities are about two orders of magnitude higher than average specific activities detected in previous studies of sea ice rafted sediments from the Arctic Ocean, (2) two independent observations of these unexpectedly high specific activities were made several years apart, (3) the sampling site is on the opposite side of the Arctic basin from potential radioactive sources such as disposal and weapons testing sites of the former Soviet Union and nuclear fuel reprocessing sites in western Europe, and (4) the closest compositional match to known geologic source regions is Banks Island, on the western edge of the Arctic Archipelago, although a smaller number of grains from one of the two samples were mineralogically matched to sediments in the Laptev Sea. Consequently, the sediments are probably not from a single distinct source and were likely mixed during sea ice transport. Coupled with previous observations of higher radionuclide specific activities in some sea ice rafted sediments relative to bottom sediments, these new observations indicate that comparatively high as well as variable radioactive contaminant burdens in ice rafted sediments must be common and geographically independent of proximity to known contaminant sources. The mechanisms that would facilitate these unexpected high radionuclide burdens in sea ice are not known and require additional study, as well as investigations of the implications for the transport and fate of contaminants in Arctic sea ice.

  19. Postglacial environmental succession of Nettilling Lake (Baffin Island, Canadian Arctic) inferred from biogeochemical and microfossil proxies

    NASA Astrophysics Data System (ADS)

    Narancic, Biljana; Pienitz, Reinhard; Chapligin, Bernhard; Meyer, Hanno; Francus, Pierre; Guilbault, Jean-Pierre

    2016-09-01

    Nettilling Lake (Baffin Island, Nunavut) is currently the largest lake in the Canadian Arctic Archipelago. Despite its enormous size, this freshwater system remains little studied until the present-day. Existing records from southern Baffin Island indicate that in the early postglacial period, the region was submerged by the postglacial Tyrell Sea due to isostatic depression previously exerted by the Laurentide Ice Sheet. However, these records are temporally and spatially discontinuous, relying on qualitative extrapolation. This paper presents the first quantitative reconstruction of the postglacial environmental succession of the Nettilling Lake basin based on a 8300 yr-long high resolution sedimentary record. Our multi-proxy investigation of the glacio-isostatic uplift and subsequent changes in paleosalinity and sediment sources is based on analyses of sediment fabric, elemental geochemistry (μ-XRF), diatom assemblage composition, as well as on the first diatom-based oxygen isotope record from the eastern Canadian Arctic. Results indicate that the Nettilling Lake basin experienced a relatively rapid and uniform marine invasion in the early Holocene, followed by progressive freshening until about 6000 yr BP when limnological conditions similar to those of today were established. Our findings present evidence for deglacial processes in the Foxe Basin that were initiated at least 400yrs earlier than previously thought.

  20. Canadian incentives for oil and gas exploration. [Applicability to USA

    SciTech Connect

    Not Available

    1980-04-01

    During the 1970s a number of different exploration and production incentive programs were put in place in Canada, in particular in the Province of Alberta, Canada's principal oil- and gas-producing province. The DOE/RA is evaluating Canadian incentives for oil and gas exploration, and this study is intended to provide information that will help guide DOE/RA in determining the applicability of Canadian incentive programs in US energy policy. The study describes and documents the fiscal structure in which the Canadian oil industry operates. The incentive features of pricing policy, taxation policy, and provincial royalty systems are discussed. A principal focus of the study is on one of the most important of Canada's specific incentive programs, the Alberta Exploratory Drilling Incentive Credit Program (EDICP). The study describes and evaluates the effect of the EDICP on increased oil and gas exploration activity. Similarly, the study also reviews and evaluates other specific incentive programs such as the Alberta Geophysical Incentive Program, Frontier Exploration Allowances, and various tar sand and heavy oil development incentives. Finally the study evaluates the applicability of Canadian incentives to US energy policy.

  1. The contribution of Alaskan, Siberian, and Canadian coastal polynas to the cold halocline layer of the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Cavalieri, Donald J.; Martin, Seelye

    1994-01-01

    Numerous Arctic Ocean circulation and geochemical studies suggest that ice growth in polynyas over the Alaskan, Siberian, and Canadian continental shelves is a source of cold, saline water which contributes to the maintenance of the Arctic Ocean halocline. The purpose of this study is to estimate for the 1978-1987 winters the contributions of Arctic coastal polynyas to the cold halocline layer of the Arctic Ocean. The study uses a combination of satellite, oceanographic, and weather data to calculate the brine fluxes from the polynyas; then an oceanic box model is used to calculate their contributions to the cold halocline layer of the Arctic Ocean. This study complements and corrects a previous study of dense water production by coastal polynyas in the Barents, Kara, and Laptev Seas.

  2. The contribution of Alaskan, Siberian, and Canadian coastal polynas to the cold halocline layer of the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Cavalieri, Donald J.; Martin, Seelye

    1994-01-01

    Numerous Arctic Ocean circulation and geochemical studies suggest that ice growth in polynyas over the Alaskan, Siberian, and Canadian continental shelves is a source of cold, saline water which contributes to the maintenance of the Arctic Ocean halocline. The purpose of this study is to estimate for the 1978-1987 winters the contributions of Arctic coastal polynyas to the cold halocline layer of the Arctic Ocean. The study uses a combination of satellite, oceanographic, and weather data to calculate the brine fluxes from the polynyas; then an oceanic box model is used to calculate their contributions to the cold halocline layer of the Arctic Ocean. This study complements and corrects a previous study of dense water production by coastal polynyas in the Barents, Kara, and Laptev Seas.

  3. Carbon Exchange and NDVI by Vegetation Community in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Gregory, F. M.; Treitz, P. M.; Scott, N. A.

    2009-12-01

    The objective of this work is to characterize trends in net carbon dioxide flux for three distinct high arctic vegetation communities. The analysis is based on field measures of CO2 flux and other biophysical variables, and multi-temporal high resolution satellite image derivitives (i.e. community class and spectral indices). Cape Bounty, located on the south coast of Melville Island in the Canadian Arctic Archipelago (74d 55m N, 109d 35m W) is representative of a high arctic ecosystem. The terrestrial landscape at Cape Bounty can be divided into three main vegetation community types that can loosely be defined along a moisture gradient: wet sedge meadow, mesic heath and polar desert. These vegetation types, along with bare rock and water bodies, can be distinguished readily on high resolution satellite imagery. Normalized Difference Vegetation Index (NDVI), a surrogate for plant productivity, can be derived and compared spatially by vegetation community and temporally by image date. Our field results suggest that only the wettest vegetation communities sustain net carbon sink status over the high arctic growing season. Composite weekly averages for wet sedge sample locations show them to be neutral to very weak net sinks at the beginning of the growing season, with carbon intake increasing to an average of 2 g/m2/hour at the peak of the growing season (i.e., late July). However, image classification by vegetation community shows that mesic heath and polar desert comprise the majority land cover of the region. These vegetation community types seem to exhibit neutral to weak carbon source status due to soil respiration which increases with higher temperatures. NDVI analysis shows the highest absolute vegetation productivity values and the greatest increases in productivity from early to peak season occur in the wet sedge meadow communities. Although low to mid Arctic sites, such as Toolik Lakes and Point Barrow in Alaska, have been intensively studied, there has as

  4. Toward daily climate scenarios for Canadian Arctic coastal zones with more realistic temperature-precipitation interdependence

    NASA Astrophysics Data System (ADS)

    Gennaretti, Fabio; Sangelantoni, Lorenzo; Grenier, Patrick

    2015-12-01

    The interdependence between climatic variables should be taken into account when developing climate scenarios. For example, temperature-precipitation interdependence in the Arctic is strong and impacts on other physical characteristics, such as the extent and duration of snow cover. However, this interdependence is often misrepresented in climate simulations. Here we use two two-dimensional (2-D) methods for statistically adjusting climate model simulations to develop plausible local daily temperature (Tmean) and precipitation (Pr) scenarios. The first 2-D method is based on empirical quantile mapping (2Dqm) and the second on parametric copula models (2Dcopula). Both methods are improved here by forcing the preservation of the modeled long-term warming trend and by using moving windows to obtain an adjustment specific to each day of the year. These methods were applied to a representative ensemble of 13 global climate model simulations at 26 Canadian Arctic coastal sites and tested using an innovative cross-validation approach. Intervariable dependence was evaluated using correlation coefficients and empirical copula density plots. Results show that these 2-D methods, especially 2Dqm, adjust individual distributions of climatic time series as adequately as one common one-dimensional method (1Dqm) does. Furthermore, although 2Dqm outperforms the other methods in reproducing the observed temperature-precipitation interdependence over the calibration period, both 2Dqm and 2Dcopula perform similarly over the validation periods. For cases where temperature-precipitation interdependence is important (e.g., characterizing extreme events and the extent and duration of snow cover), both 2-D methods are good options for producing plausible local climate scenarios in Canadian Arctic coastal zones.

  5. Summertime sources of dimethyl sulfide in the Canadian Arctic Archipelago and Baffin Bay

    NASA Astrophysics Data System (ADS)

    Mungall, E. L.; Croft, B.; Lizotte, M.; Thomas, J. L.; Murphy, J. G.; Levasseur, M.; Martin, R. V.; Wentzell, J. J. B.; Liggio, J.; Abbatt, J. P. D.

    2015-12-01

    Dimethyl sulfide (DMS) plays a major role in the global sulfur cycle. In addition, its atmospheric oxidation products contribute to the formation and growth of atmospheric aerosol particles, thereby influencing cloud condensation nuclei (CCN) populations and thus cloud formation. The pristine summertime Arctic atmosphere is a CCN-limited regime, and is thus very susceptible to the influence of DMS. However, atmospheric DMS mixing ratios have only rarely been measured in the summertime Arctic. During July-August 2014, we conducted the first high time resolution (10 Hz) DMS mixing ratio measurements for the Eastern Canadian Archipelago and Baffin Bay as one component of the Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments (NETCARE). DMS mixing ratios ranged from below the detection limit of 4 to 1155 pptv (median 186 pptv). A set of transfer velocity parameterizations from the literature coupled with our atmospheric and coincident seawater DMS measurements yielded air-sea DMS flux estimates ranging from 0.02-12 μmol m-2 d-1, the first published for this region in summer. Airmass trajectory analysis using FLEXPART-WRF and chemical transport modeling using GEOS-Chem indicated that local sources (Lancaster Sound and Baffin Bay) were the dominant contributors to the DMS measured along the 21 day ship track, with episodic transport from the Hudson Bay System. After adjusting GEOS-Chem oceanic DMS values in the region to match measurements, GEOS-Chem reproduced the major features of the measured time series, but remained biased low overall (median 67 pptv). We investigated non-marine sources that might contribute to this bias, such as DMS emissions from lakes, biomass burning, melt ponds and coastal tundra. While the local marine sources of DMS dominated overall, our results suggest that non-local and possibly non-marine sources episodically contributed strongly to the observed summertime Arctic DMS mixing ratios.

  6. Occurrence and distribution of bacterial tetraether lipids in the Eocene Canadian Arctic paleosols: paleoclimate implications (Invited)

    NASA Astrophysics Data System (ADS)

    Mehay, S.; Jahren, A.; Schubert, B.; Eberle, J. J.; Summons, R. E.

    2010-12-01

    The Early to Middle Eocene (~56-45 Ma) was a “greenhouse” interval with average global temperatures warmer than any other time in the Cenozoic. This period was characterized by warm climates at high latitude leading to lush forests and the arrival of new mammal groups north of the Arctic Circle (>73°N). Glycerol dialkyl glycerol tetraethers (GDGTs) are membrane-spanning lipids characteristic of certain archaea and bacteria and it has been demonstrated that branched and cyclic GDGTs derived from soil bacteria vary in structure as a function of environmental factors. Proxies based on the relative abundances of methyl branched and cyclopentyl bacterial tetraethers are hypothesized to correlate with mean annual air temperature and soil pH. Here we present the occurrence and distribution of GDGTs in a range of paleosol and sediment samples from Axel Heiberg Island and Ellesmere Island, Nunavut (eastern Canadian Arctic) and Banks Island in the Northwest Territories (western Canadian Arctic). Preliminary results on 11 paleosol samples from the middle Eocene-aged Geodetic Hills Fossil Forest on Axel Heiberg Island indicate a mean annual air temperature of about 9°C. Earlier paleotemperature estimates for Axel Heiberg Island led to values ranging from 9°C to 15°C for the Middle Eocene. Recent temperature prediction for Ellesmere Island (Early Eocene) based upon oxygen isotope ratios of biogenic phosphate from mammal and fish fossils led to ~8°C. In contrast, GDGTs from a marine sedimentary sequence from Lomonosov Ridge in the central Arctic Ocean led to much higher Early Eocene temperature. Thus, the evaluation of the paleotemperature for the Early to Middle Eocene is still a subject of controversy. Ongoing GDGTs analysis of samples from Ellesmere and Banks Islands should give a more comprehensive paleoenvironmental description of the Eocene Arctic. Differences observed between the various paleotemperature estimates will also be discussed. GDGTs distributions are

  7. Winter temperature conditions (1670-2010) reconstructed from varved sediments, western Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Amann, Benjamin; Lamoureux, Scott F.; Boreux, Maxime P.

    2017-09-01

    Advances in paleoclimatology from the Arctic have provided insights into long-term climate conditions. However, while past annual and summer temperature have received considerable research attention, comparatively little is known about winter paleoclimate. Arctic winter is of special interest as it is the season with the highest sensitivity to climate change, and because it differs substantially from summer and annual measures. Therefore, information about past changes in winter climate is key to improve our knowledge of past forced climate variability and to reduce uncertainty in climate projections. In this context, Arctic lakes with snowmelt-fed catchments are excellent potential winter climate archives. They respond strongly to snowmelt-induced runoff, and indirectly to winter temperature and snowfall conditions. To date, only a few well-calibrated lake sediment records exist, which appear to reflect site-specific responses with differing reconstructions. This limits the possibility to resolve large-scale winter climate change prior the instrumental period. Here, we present a well-calibrated quantitative temperature and snowfall record for the extended winter season (November through March; NDJFM) from Chevalier Bay (Melville Island, NWT, Canadian Arctic) back to CE 1670. The coastal embayment has a large catchment influenced by nival terrestrial processes, which leads to high sedimentation rates and annual sedimentary structures (varves). Using detailed microstratigraphic analysis from two sediment cores and supported by μ-XRF data, we separated the nival sedimentary units (spring snowmelt) from the rainfall units (summer) and identified subaqueous slumps. Statistical correlation analysis between the proxy data and monthly climate variables reveals that the thickness of the nival units can be used to predict winter temperature (r = 0.71, pc < 0.01, 5-yr filter) and snowfall (r = 0.65, pc < 0.01, 5-yr filter) for the western Canadian High Arctic over the last

  8. Surface water types in the Western Canadian Arctic: geochemical evolution and aquatic carbon transport

    NASA Astrophysics Data System (ADS)

    Dean, Joshua F.; Billett, Mike F.; Dinsmore, Kerry J.; Lessels, Jason S.; Street, Lorna; Washbourne, Ian; Subke, Jens-Arne; Tetzlaff, Doerthe; Baxter, Robert; Wookey, Philip A.

    2015-04-01

    Arctic surface waters are a substantial conduit for terrestrial C flow as well as a potential source of GHGs to the atmosphere - a significant positive feedback to global climate warming and a key component of the net ecosystem carbon balance in permafrost regions. As temperatures rise in the Arctic, permafrost thaw deepens releasing C from the landscape into the aquatic system making streams and lakes increasingly important conduits and reactors of both allochthonous and autochthonous C. The HYDRA project ('Permafrost catchments in transition: hydrological controls on carbon cycling and greenhouse gas budgets'), aims to quantify the assimilation of C and the controls of C movement between the plant-soil-water-atmosphere continuum. The specific aspect of the project presented here considers the different aquatic pathways in warming Arctic permafrost catchments, and the potential role that they play in GHG emissions and aquatic C cycling. This study presents the surface water geochemistry of Siksik Creek, a small (

  9. Photodemethylation of Methylmercury in Eastern Canadian Arctic Thaw Pond and Lake Ecosystems.

    PubMed

    Girard, Catherine; Leclerc, Maxime; Amyot, Marc

    2016-04-05

    Permafrost thaw ponds of the warming Eastern Canadian Arctic are major landscape constituents and often display high levels of methylmercury (MeHg). We examined photodegradation potentials in high-dissolved organic matter (DOC) thaw ponds on Bylot Island (BYL) and a low-DOC oligotrophic lake on Cornwallis Island (Char Lake). In BYL, the ambient MeHg photodemethylation (PD) rate over 48 h of solar exposure was 6.1 × 10(-3) m(2) E(-1), and the rate in MeHg amended samples was 9.3 × 10(-3) m(2) E(-1). In contrast, in low-DOC Char Lake, PD was only observed in the first 12 h, which suggests that PD may not be an important loss process in polar desert lakes. Thioglycolic acid addition slowed PD, while glutathione and chlorides did not impact northern PD rates. During an ecosystem-wide experiment conducted in a covered BYL pond, there was neither net MeHg increase in the dark nor loss attributable to PD following re-exposure to sunlight. We propose that high-DOC Arctic thaw ponds are more prone to MeHg PD than nearby oligotrophic lakes, likely through photoproduction of reactive species rather than via thiol complexation. However, at the ecosystem level, these ponds, which are widespread through the Arctic, remain likely sources of MeHg for neighboring systems.

  10. Holocene climate and vegetation change on Victoria Island, western Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Peros, Matthew C.; Gajewski, Konrad

    2008-02-01

    A detailed pollen record from Victoria Island provides the first quantitative Holocene climate reconstruction from the western Canadian Arctic. The pollen percentage data indicate that Arctic herbs increased over the Holocene in response to long-term cooling. The influx of locally and regionally derived pollen grains varies throughout the core and tracks several major changes observed in the biogenic silica record from Arolik Lake, Alaska, and the GISP2 ice-core, suggesting that climate change closely controlled Arctic plant productivity. Using modern analogue and transfer function techniques, we generated quantitative reconstructions of mean July temperature and total annual precipitation for the past 10 000 years, to place recent climate changes within the context of Holocene climate variability. The quantitative reconstructions indicate that July temperature cooled by 1-1.5 °C during the Holocene. The pollen-based reconstructions record an increase in temperature of ˜0.5 °C over the last 100 years, and the pollen percentage and influx data indicate impacts of recent warming on the regional vegetation.

  11. Wastewater treatment and public health in Nunavut: a microbial risk assessment framework for the Canadian Arctic.

    PubMed

    Daley, Kiley; Jamieson, Rob; Rainham, Daniel; Truelstrup Hansen, Lisbeth

    2017-02-21

    Wastewater management in Canadian Arctic communities is influenced by several geographical factors including climate, remoteness, population size, and local food-harvesting practices. Most communities use trucked collection services and basic treatment systems, which are capable of only low-level pathogen removal. These systems are typically reliant solely on natural environmental processes for treatment and make use of existing lagoons, wetlands, and bays. They are operated in a manner such that partially treated wastewater still containing potentially hazardous microorganisms is released into the terrestrial and aquatic environment at random times. Northern communities rely heavily on their local surroundings as a source of food, drinking water, and recreation, thus creating the possibility of human exposure to wastewater effluent. Human exposure to microbial hazards present in municipal wastewater can lead to acute gastrointestinal illness or more severe disease. Although estimating the actual disease burdens associated with wastewater exposures in Arctic communities is challenging, waterborne- and sanitation-related illness is believed to be comparatively higher than in other parts of Canada. This review offers a conceptual framework and evaluation of current knowledge to enable the first microbial risk assessment of exposure scenarios associated with food-harvesting and recreational activities in Arctic communities, where simplified wastewater systems are being operated.

  12. Inuit Student Teachers' Agency, Positioning and Symbolic Action: Reflections from a "Qallunaat" on Music Teaching in the Canadian Arctic

    ERIC Educational Resources Information Center

    Russell, Joan

    2006-01-01

    This article examines how three Inuit student teachers in the Nunavut Teacher Education Program invested their "social and cultural capital" during a music course for classroom teachers, which the author taught in the Canadian Arctic. She describes how, through the musical games they invented for use in Inuit classrooms, these students…

  13. Inuit Student Teachers' Agency, Positioning and Symbolic Action: Reflections from a "Qallunaat" on Music Teaching in the Canadian Arctic

    ERIC Educational Resources Information Center

    Russell, Joan

    2006-01-01

    This article examines how three Inuit student teachers in the Nunavut Teacher Education Program invested their "social and cultural capital" during a music course for classroom teachers, which the author taught in the Canadian Arctic. She describes how, through the musical games they invented for use in Inuit classrooms, these students…

  14. The Unexpected Re-Growth of Ice-Entombed Bryophytes in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    La Farge, C.

    2014-12-01

    The rapid retreat of glaciers and ice caps throughout the Canadian Arctic is exposing pristine vegetation preserved beneath cold-based ice. For the past half century this vegetation has been consistently reported as dead. This interpretation has been overturned by the successful re-growth of Little Ice Age (1550-1850 AD) bryophytes emerging from the Teardrop Glacier, Sverdrup Pass, Ellesmere Island (79° N) collected in 2009. Some populations showed regeneration in the field and lab experiments confirmed their capacity to regrow. The species richness of these subglacial populations is exceptional, comprising >62 species that represent 44% of the extant bryophyte flora of Sverdrup Pass. Cold-based glaciers are known to provide critical habitats for a variety of microbiota (i.e., fungi, algae, cyanobacteria, bacteria and viruses) in high latitude ecosystems. The regeneration of Little Ice Age bryophytes fundamentally expands the concept of biological refugia to land plants that was previously restricted to survival above and beyond glacial margins. Given this novel understanding of subglacial ecosystems, fieldwork is now being extended southward to plateau ice caps on Baffin Island, Nunavut, where ice retreat is exposing subglacial populations of greater antiquity (thousands to tens of thousands of radiocarbon years before present). Bryophytes by nature are totipotent (stem cell equivalency) and poikilohydric (desiccation tolerance), which facilitate their unique adaptation to extreme environments. Continuity of the Arctic bryophyte flora extends back through the Holocene to the late Tertiary [Beaufort Fm, 2-5 Ma], when the majority of taxa were the same, based on records spanning the archipelago from Ellesmere to Banks Island. This record contrasts with that of vascular plants, which have had a number of extinctions, necessitating recolonization of arctic populations from outside the region. The biological significance of a stable bryophyte element highlights their

  15. Determining diatom ecotones and their relationship to terrestrial ecoregion designations in the central Canadian Arctic Islands.

    PubMed

    Antoniades, Dermot; Douglas, Marianne S V; Michelutti, Neal; Smol, John P

    2014-08-01

    Ecotones are key areas for the detection of global change because many are predicted to move with shifts in climate. Prince of Wales Island, in the Canadian Arctic Archipelago, spans the transition between mid- to high-Arctic ecoregions. We analyzed limnological variables and recent diatom assemblages from its lakes and ponds to determine if assemblages reflected this ecotone. Limnological gradients were short, and water chemistry explained 20.0% of diatom variance in a redundancy analysis (RDA), driven primarily by dissolved organic carbon, Ca and SO4 . Most taxa were small, benthic forms; key taxa such as planktonic Cyclotella species were restricted to the warmer, southern portion of the study area, while benthic Staurosirella were associated with larger, ice-dominated lakes. Nonetheless, there were no significant changes in diatom assemblages across the mid- to high-Arctic ecoregion boundary. We combined our data set with one from nearby Cornwallis Island to expand the study area and lengthen its environmental gradients. Within this expanded data set, 40.6% of the diatom variance was explained by a combination of water chemistry and geographic variables, and significant relationships were revealed between diatom distributions and key limnological variables, including pH, specific conductivity, and chl-a. Using principal coordinates analysis, we estimated community turnover with latitude and applied piecewise linear regression to determine diatom ecotone positions. A pronounced transition was present between Prince of Wales Island and the colder, more northerly Cornwallis Island. These data will be important in detecting any future northward ecotone movement in response to predicted Arctic climate warming in this highly sensitive region. © 2014 Phycological Society of America.

  16. Recent progress on our understanding of the biological effects of mercury in fish and wildlife in the Canadian Arctic.

    PubMed

    Scheuhammer, Anton; Braune, Birgit; Chan, Hing Man; Frouin, Héloïse; Krey, Anke; Letcher, Robert; Loseto, Lisa; Noël, Marie; Ostertag, Sonja; Ross, Peter; Wayland, Mark

    2015-03-15

    This review summarizes our current state of knowledge regarding the potential biological effects of mercury (Hg) exposure on fish and wildlife in the Canadian Arctic. Although Hg in most freshwater fish from northern Canada was not sufficiently elevated to be of concern, a few lakes in the Northwest Territories and Nunavut contained fish of certain species (e.g. northern pike, Arctic char) whose muscle Hg concentrations exceeded an estimated threshold range (0.5-1.0 μg g(-1) wet weight) within which adverse biological effects begin to occur. Marine fish species generally had substantially lower Hg concentrations than freshwater fish; but the Greenland shark, a long-lived predatory species, had mean muscle Hg concentrations exceeding the threshold range for possible effects on health or reproduction. An examination of recent egg Hg concentrations for marine birds from the Canadian Arctic indicated that mean Hg concentration in ivory gulls from Seymour Island fell within the threshold range associated with adverse effects on reproduction in birds. Mercury concentrations in brain tissue of beluga whales and polar bears were generally lower than levels associated with neurotoxicity in mammals, but were sometimes high enough to cause subtle neurochemical changes that can precede overt neurotoxicity. Harbour seals from western Hudson Bay had elevated mean liver Hg concentrations along with comparatively high muscle Hg concentrations indicating potential health effects from methylmercury (MeHg) exposure on this subpopulation. Because current information is generally insufficient to determine with confidence whether Hg exposure is impacting the health of specific fish or wildlife populations in the Canadian Arctic, biological effects studies should comprise a major focus of future Hg research in the Canadian Arctic. Additionally, studies on cellular interactions between Hg and selenium (Se) are required to better account for potential protective effects of Se on Hg

  17. Measurements of the dissolved inorganic carbon system and associated biogeochemical parameters in the Canadian Arctic, 1974-2009

    NASA Astrophysics Data System (ADS)

    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.

    2014-03-01

    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. The data set is available for download on the CDIAC (Carbon Dioxide Information Analysis Center) website: Arctic_Database/"target="_blank">http://cdiac.ornl.gov/ftp/oceans/IOS_Arctic_Database/ (doi:10.3334/CDIAC/OTG.IOS_ARCT_CARBN).

  18. Measurements of the dissolved inorganic carbon system and associated biogeochemical parameters in the Canadian Arctic, 1974-2009

    NASA Astrophysics Data System (ADS)

    Giesbrecht, K. E.; Miller, L. A.; Zimmermann, S.; Carmack, E.; Johnson, W. K.; Macdonald, R. W.; McLaughlin, F.; Mucci, A.; Williams, W. J.; Wong, C. S.; Yamamoto-Kawai, M.

    2013-06-01

    We have assembled and conducted primary quality control on previously publically-unavailable water column measurements of the dissolved inorganic carbon system and associated biogeochemical parameters (oxygen, nutrients, etc.) made on 25 cruises in the subarctic and Arctic regions dating from as far back as 1974. The measurements are primarily from the western side of the Canadian Arctic, but also include data 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 dataset 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 yr and provides an opportunity to increase our understanding of temporal changes in the inorganic carbon system in northern waters and the Arctic Ocean. The dataset is available for download on the CDIAC website: Arctic_Database/"target="_blank">http://cdiac.ornl.gov/ftp/oceans/IOS_Arctic_Database/ (doi:10.3334/CDIAC/OTG.IOS_ARCT_CARBN).

  19. Pipeline under the arctic ice: the Polar Gas Project

    SciTech Connect

    Kaustinen, O.M.

    1982-06-01

    The Polar Gas Project was established in 1972 to determine the best means of moving frontier natural gas from Canada's high arctic to southern markets. Pipeline was found to be most feasible. Several pipeline routings from two major supply areas--the MacKenzie Delta/Beaufort Sea region, and the Sverdrup Basin of the Arctic Islands--have been considered. Field programs to determine the type and ice content of soils along the route have been undertaken. The most challenging engineering aspect will be two marine crossings in arctic waters at either end of Victoria Island, at Dolphin and Union Strait, and at McClure's strait. The ''Ice Hole Bottom Pull'' technique has been recommended, and is illustrated in detail. The planned pipeline demonstration would significantly enhance the current state-of-the-art for deepwater pipelining worldwide.

  20. Looking for little green bugs and methane in the Canadian high Arctic. (Invited)

    NASA Astrophysics Data System (ADS)

    Whyte, L.; Niederberger, T.; Perreault, N.; Mykytczuk, N.; Sherwood Lollar, B.; Onstott, T. C.; Andersen, D. T.; Pollard, W. H.; Greer, C.

    2010-12-01

    The primary targets for astrobiology investigations of other solar system bodies are Mars as well as Europa and Enceladus. Extremely cold temperatures characterize these targets, and as such, the best terrestrial analogues may be the Earth's polar regions; the Canadian high Arctic offers several unique cryoenvironments that resemble the conditions that are known, or are suspected, to exist on Mars. This presentation will describe our recent research examining microbial life in the unique cold saline springs and permafrost habitats on Axel Heiberg Island with the overall goals of determining the low temperature limits of microbial life on Earth and whether microbial communities inhabiting such cryoenvironments (subzero habitats) are active at ambient subzero tem-peratures. The presentation will focus on the microbiology and geochemistry of the Lost Hammer Spring (LH) site which provides a model of how a methane seep can form in cryoenvironments characterized by thick extensive permafrost in an area with an average annual air temperature of -15C and air temperatures below -40C common during the winter months and provides a mechanism that could possibly be contributing to reported methane plumes or hotspots on Mars. This highly unique hypersaline (23% salinity), subzero (-5C) environment supports a viable microbial community capable of activity at temperatures as low as -10C; in the LH spring, the methane itself can act as an energy and carbon source for sustaining anaerobic methane oxidation-based microbial metabolism, rather than methanogenesis, within these extreme environmental constraints. It has been recently postulated that the ~10 ppb CH4 reported in the Mars atmosphere may originate from localized “hotspots” or “plumes” of methane arising from the Martian surface. The origin of these plumes is under debate and could be attributable to either geological or biological sources, the latter including methanogenesis by microbial communities inhabiting the

  1. Concentrations of selected essential and non-essential elements in arctic fox (Alopex lagopus) and wolverines (Gulo gulo) from the Canadian Arctic.

    PubMed

    Hoekstra, P F; Braune, B M; Elkin, B; Armstrong, F A J; Muir, D C G

    2003-06-20

    Arctic fox (Alopex lagopus) and wolverine (Gulo gulo) tissues were collected in the Canadian Arctic from 1998 to 2001 and analyzed for various essential and non-essential elements. Several elements (Ag, Al, As, B, Ba, Be, Co, Cr, Mo, Ni, Sb, Sn, Sr, Tl, U and V) were near or below the detection limits in >95% arctic fox and wolverine samples. Concentrations of Cd, Cu, Fe, total Hg (THg), Mn, Pb, Se and Zn were quantifiable in >50% of the samples analyzed and reported herein. Hepatic elemental concentrations were not significantly different among arctic foxes collected at Ulukhaqtuuq (Holman), NT (n=13) and Arviat, NU (n=50), but were significantly greater than concentrations found in wolverine liver from Kugluktuk (Coppermine), NU (n=12). The mean (+/-1 S.E.) concentrations of Cd in kidney were also significantly greater in arctic fox (1.08+/-0.19 microg g(-1) wet wt.) than wolverine (0.67+/-0.18 microg g(-1) wet wt.). However, mean hepatic Cu concentrations (Ulukhaqtuuq: 5.5+/-0.64; Arviat: 7.1+/-0.49 microg g(-1) wet wt.) in arctic foxes were significantly lower than in wolverines (32+/-3.3 microg g(-1) wet wt.). Hepatic total Hg (THg) concentrations in arctic fox from this study were not significantly different from specimens collected in 1973, suggesting that THg concentrations have not changed dramatically over the past 30 years. The mono-methylmercury (MeHg) concentrations in selected (n=10) arctic fox liver samples from Arviat (0.14+/-0.07 microg g(-1) wet wt.) comprised 14% of THg. While the molar concentrations of THg were correlated with Se in arctic foxes and wolverines, the hepatic Hg/Se molar ratios were consistently lower than unity; suggesting that Se-mediated detoxification pathways of Hg are not overwhelmed at current exposure.

  2. Small thaw ponds: an unaccounted source of methane in the Canadian high Arctic.

    PubMed

    Negandhi, Karita; Laurion, Isabelle; Whiticar, Michael J; Galand, Pierre E; Xu, Xiaomei; Lovejoy, Connie

    2013-01-01

    Thawing permafrost in the Canadian Arctic tundra leads to peat erosion and slumping in narrow and shallow runnel ponds that surround more commonly studied polygonal ponds. Here we compared the methane production between runnel and polygonal ponds using stable isotope ratios, ¹⁴C signatures, and investigated potential methanogenic communities through high-throughput sequencing archaeal 16S rRNA genes. We found that runnel ponds had significantly higher methane and carbon dioxide emissions, produced from a slightly larger fraction of old carbon, compared to polygonal ponds. The methane stable isotopic signature indicated production through acetoclastic methanogenesis, but gene signatures from acetoclastic and hydrogenotrophic methanogenic Archaea were detected in both polygonal and runnel ponds. We conclude that runnel ponds represent a source of methane from potentially older C, and that they contain methanogenic communities able to use diverse sources of carbon, increasing the risk of augmented methane release under a warmer climate.

  3. Persistent halogenated organic contaminants and mercury in northern fulmars (Fulmarus glacialis) from the Canadian Arctic.

    PubMed

    Braune, Birgit M; Mallory, Mark L; Butt, Craig M; Mabury, Scott A; Muir, Derek C G

    2010-12-01

    Northern fulmars from two breeding colonies in the Canadian Arctic, Cape Vera and Prince Leopold Island, were analyzed for organochlorine pesticides, PCBs, perfluorinated compounds (PFCs) and total mercury (Hg). Hepatic concentrations of organochlorines and Hg were highest in the male fulmars from Cape Vera. Perfluorooctane sulfonate (PFOS) concentrations did not vary significantly between sexes or colonies. However, concentrations of the perfluorinated carboxylates (PFCAs) were higher in fulmars from Cape Vera than Prince Leopold Island. The C(11)-C(15) PFCAs averaged 90% of the PFCA profile at both colonies. Polychorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and non-ortho PCBs (NO-PCBs) were measured only in birds from Prince Leopold Island. Concentrations of PCDDs, PCDFs, NO-PCBs and Toxic Equivalents (TEQs) did not differ significantly between sexes. ΣTEQ was comprised mainly of ΣTEQ(PCDF). Concentrations of Hg and the persistent halogenated compounds reported in this study were below published toxicological threshold values for wild birds.

  4. Small Thaw Ponds: An Unaccounted Source of Methane in the Canadian High Arctic

    PubMed Central

    Negandhi, Karita; Laurion, Isabelle; Whiticar, Michael J.; Galand, Pierre E.; Xu, Xiaomei; Lovejoy, Connie

    2013-01-01

    Thawing permafrost in the Canadian Arctic tundra leads to peat erosion and slumping in narrow and shallow runnel ponds that surround more commonly studied polygonal ponds. Here we compared the methane production between runnel and polygonal ponds using stable isotope ratios, 14C signatures, and investigated potential methanogenic communities through high-throughput sequencing archaeal 16S rRNA genes. We found that runnel ponds had significantly higher methane and carbon dioxide emissions, produced from a slightly larger fraction of old carbon, compared to polygonal ponds. The methane stable isotopic signature indicated production through acetoclastic methanogenesis, but gene signatures from acetoclastic and hydrogenotrophic methanogenic Archaea were detected in both polygonal and runnel ponds. We conclude that runnel ponds represent a source of methane from potentially older C, and that they contain methanogenic communities able to use diverse sources of carbon, increasing the risk of augmented methane release under a warmer climate. PMID:24236014

  5. Propagation measurements on a troposcatter link in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Bilodeau, C.; McCormick, K. S.

    1994-07-01

    Experimental results of radio propagation measurements at 853 MHz are given for a 500 km troposcatter link in the Canadian High Arctic. The experimental data were acquired using a narrow band measurement system that was developed to permit a transmitting power of only 100 Watts while using a 4.5 meter dish at each end of the link. The system includes a digital signal processor (DSP) receiver for signal strength computation and a high stability noise source reference for amplitude calibration. The main characteristics of this system are described in this paper. Detailed fading distributions are presented for examples of slow and fast fading periods and compared with Rayleigh distributions. An estimate of the long term median path loss is made and compared with values predicted using accepted techniques. The results are believed to be the first ever presented for a microwave troposcatter link above the 80th parallel.

  6. Sampling criteria for identifying human biomonitoring chemical differences in the Canadian Arctic.

    PubMed

    Curren, Meredith S; Davis, Karelyn; Van Oostdam, Jay

    2014-01-01

    Human biomonitoring studies in the Canadian Arctic have measured a wide range of metals and persistent organic pollutants in Aboriginal and non-Aboriginal mothers during two time periods in the Northwest Territories and Nunavut. This analysis provides preliminary estimates on sample sizes and sampling frequencies required to measure significant changes in maternal blood concentrations for PCB 153 and total mercury. For example, sample sizes of 35-40 mothers permit the detection of a 40% decrease in these chemical concentrations between two groups (e.g. communities or regions). Improvements in method sensitivity can be achieved by on-going sampling over multiple time periods (e.g. 4 or 5) in these regions, or increasing sample sizes.

  7. Food expenditure patterns in the Canadian Arctic show cause for concern for obesity and chronic disease

    PubMed Central

    2014-01-01

    Background Little is understood about the economic factors that have influenced the nutrition transition from traditional to store-bought foods that are typically high in fat and sugar amongst people living in the Canadian Arctic. This study aims to determine the pattern of household food expenditure in the Canadian Arctic. Method Local food prices were collected over 12 months in six communities in Nunavut and the Northwest Territories. Dietary intake data were collected from 441 adults using a validated quantitative food frequency questionnaire. Money spent on six food groups was calculated along with the cost of energy and selected nutrients per person. Results Participants spent approximately 10% of total food expenditure on each of the food groups of fruit/vegetables, grains and potatoes, and dairy, 17% on traditional meats (e.g. caribou, goose, char, and seal liver), and 20% on non-traditional meats (e.g. beef, pork, chicken, fish, and processed meats). Non-nutrient-dense foods (NNDF) accounted for 34% of food expenditure. Younger participants (<30 years) spent more on NNDF and less on traditional meats compared with the older age groups. Participants with higher levels of formal education spent more on fruit and vegetables and less on traditional meats, when compared with participants with lower levels of formal education. Conclusions Participants spent most household income on NNDF, a possible consequence of generation discrepancy between younger and older participants. The tendency toward NNDF, particularly among youth, should be addressed with an assessment of predictive factors and the development of targeted approaches to population-based interventions. PMID:24739761

  8. Food expenditure patterns in the Canadian Arctic show cause for concern for obesity and chronic disease.

    PubMed

    Pakseresht, Mohammadreza; Lang, Rosalyn; Rittmueller, Stacey; Roache, Cindy; Sheehy, Tony; Batal, Malek; Corriveau, Andre; Sharma, Sangita

    2014-04-17

    Little is understood about the economic factors that have influenced the nutrition transition from traditional to store-bought foods that are typically high in fat and sugar amongst people living in the Canadian Arctic. This study aims to determine the pattern of household food expenditure in the Canadian Arctic. Local food prices were collected over 12 months in six communities in Nunavut and the Northwest Territories. Dietary intake data were collected from 441 adults using a validated quantitative food frequency questionnaire. Money spent on six food groups was calculated along with the cost of energy and selected nutrients per person. Participants spent approximately 10% of total food expenditure on each of the food groups of fruit/vegetables, grains and potatoes, and dairy, 17% on traditional meats (e.g. caribou, goose, char, and seal liver), and 20% on non-traditional meats (e.g. beef, pork, chicken, fish, and processed meats). Non-nutrient-dense foods (NNDF) accounted for 34% of food expenditure. Younger participants (<30 years) spent more on NNDF and less on traditional meats compared with the older age groups. Participants with higher levels of formal education spent more on fruit and vegetables and less on traditional meats, when compared with participants with lower levels of formal education. Participants spent most household income on NNDF, a possible consequence of generation discrepancy between younger and older participants. The tendency toward NNDF, particularly among youth, should be addressed with an assessment of predictive factors and the development of targeted approaches to population-based interventions.

  9. Profile of persistent chlorinated contaminants, including selected chiral compounds, in wolverine (Gulo gulo) livers from the Canadian Arctic.

    PubMed

    Hoekstra, P F; Braune, B M; Wong, C S; Williamson, M; Elkin, B; Muir, D C G

    2003-11-01

    Wolverines (Gulo gulo) are circumpolar omnivores that live throughout the alpine and arctic tundra ecosystem. Wolverine livers were collected at Kugluktuk (Coppermine), NU (n=12) in the western Canadian Arctic to report, for the first time, the residue patterns of persistent organochlorine contaminants (OCs) in this species. The enantiomer fractions (EFs) of several chiral OCs, including PCB atropisomers, in wolverines were also determined. Results were compared to OC concentrations and EFs of chiral contaminants in arctic fox (Alopex lagopus) from Ulukhaqtuuq (Holman), NT (n=20); a closely related species that scavenges the marine and terrestrial arctic environment. The rank order of hepatic concentrations for sum ( summation operator ) OC groups in wolverines were polychlorinated biphenyls ( summation operator PCB)>chlordane-related components ( summation operator CHLOR)>DDT-related compounds ( summation operator DDT)>hexachlorocyclohexane isomers ( summation operator HCHs). The most abundant OC analytes detected in wolverine liver were PCB-153, PCB-180, and oxychlordane (OXY). Wolverine age and gender did not influence OC concentrations, which were comparable to lipid-normalized values in arctic fox. The EFs of several chiral OCs (alpha-HCH, cis- and trans-chlordane, OXY, heptachlor exo-epoxide) and PCB atropisomers (PCB-136, 149) were nonracemic in arctic fox and wolverine liver and similar to those previously calculated in arctic fox and polar bears from Iceland and the Canadian Arctic. Results suggest that these species have similar ability to biotransform OCs. As well, contaminant profiles suggest that terrestrial mammals do not represent the major source of OC exposure to wolverines and that wolverines are scavenging more contaminated prey items, such as marine mammals. While summation operator PCB did not exceed the concentrations associated with mammalian reproductive impairment, future research is required to properly evaluate the potential affect of

  10. Benthic macroinfaunal community structure, resource utilisation and trophic relationships in two Canadian Arctic Archipelago polynyas.

    PubMed

    Mäkelä, Anni; Witte, Ursula; Archambault, Philippe

    2017-01-01

    Climate change driven alterations to patterns of Arctic marine primary production, with increasing phytoplankton- and decreasing ice algal production, have the potential to change the resource utilisation and trophic structure of the benthic communities relying on the algae for food. To predict the benthic responses to dietary changes, we studied the macroinfaunal community compositions, and used the faunal δ13C and δ15N signatures to investigate their main food sources and trophic positions in North Water (NOW) and Lancaster Sound (LS) polynyas in the Canadian Arctic Archipelago. Macroinfaunal density (10 952 ind. m-2) and biomass (3190 mg C m-2) recorded in NOW were higher than previously found in the Arctic at depths >500m, and significantly higher than in LS (8355 ind. m-2 and 2110 mg C m-2). This was attributed to higher particulate organic matter fluxes to seafloor in NOW. Polychaetes were significant taxa at both sites in terms of density and biomass, and in addition crustacean density in NOW and bivalve density in LS were high. Facultative filter and surface deposit feeders were highly prevalent at both sites, suggesting feeding plasticity is a successful strategy for accessing different food sources. The macrofaunal δ13C signatures reflected the signatures of pelagic particulate organic matter at the sites, and an isotope mixing model confirmed phytoplankton as the main food source for most taxa and feeding guilds. The food web length in LS was longer than in NOW (3.2 vs. 2.8 trophic levels). This was attributed to a larger reliance on reworked organic matter by the benthic community in LS, whereas the high export fluxes at the highly productive NOW resulted in higher rates of selective consumption of fresh algal matter. Despite studies suggesting that loss of ice algae from consumer diets in the Arctic might have a negative impact on the benthos, this study suggests that Arctic macrobenthic communities thrive using phytoplankton as their main food

  11. Benthic macroinfaunal community structure, resource utilisation and trophic relationships in two Canadian Arctic Archipelago polynyas

    PubMed Central

    Witte, Ursula; Archambault, Philippe

    2017-01-01

    Climate change driven alterations to patterns of Arctic marine primary production, with increasing phytoplankton- and decreasing ice algal production, have the potential to change the resource utilisation and trophic structure of the benthic communities relying on the algae for food. To predict the benthic responses to dietary changes, we studied the macroinfaunal community compositions, and used the faunal δ13C and δ15N signatures to investigate their main food sources and trophic positions in North Water (NOW) and Lancaster Sound (LS) polynyas in the Canadian Arctic Archipelago. Macroinfaunal density (10 952 ind. m-2) and biomass (3190 mg C m-2) recorded in NOW were higher than previously found in the Arctic at depths >500m, and significantly higher than in LS (8355 ind. m-2 and 2110 mg C m-2). This was attributed to higher particulate organic matter fluxes to seafloor in NOW. Polychaetes were significant taxa at both sites in terms of density and biomass, and in addition crustacean density in NOW and bivalve density in LS were high. Facultative filter and surface deposit feeders were highly prevalent at both sites, suggesting feeding plasticity is a successful strategy for accessing different food sources. The macrofaunal δ13C signatures reflected the signatures of pelagic particulate organic matter at the sites, and an isotope mixing model confirmed phytoplankton as the main food source for most taxa and feeding guilds. The food web length in LS was longer than in NOW (3.2 vs. 2.8 trophic levels). This was attributed to a larger reliance on reworked organic matter by the benthic community in LS, whereas the high export fluxes at the highly productive NOW resulted in higher rates of selective consumption of fresh algal matter. Despite studies suggesting that loss of ice algae from consumer diets in the Arctic might have a negative impact on the benthos, this study suggests that Arctic macrobenthic communities thrive using phytoplankton as their main food

  12. Projected polar bear sea ice habitat in the Canadian Arctic Archipelago.

    PubMed

    Hamilton, Stephen G; Castro de la Guardia, Laura; Derocher, Andrew E; Sahanatien, Vicki; Tremblay, Bruno; Huard, David

    2014-01-01

    Sea ice across the Arctic is declining and altering physical characteristics of marine ecosystems. Polar bears (Ursus maritimus) have been identified as vulnerable to changes in sea ice conditions. We use sea ice projections for the Canadian Arctic Archipelago from 2006 - 2100 to gain insight into the conservation challenges for polar bears with respect to habitat loss using metrics developed from polar bear energetics modeling. Shifts away from multiyear ice to annual ice cover throughout the region, as well as lengthening ice-free periods, may become critical for polar bears before the end of the 21st century with projected warming. Each polar bear population in the Archipelago may undergo 2-5 months of ice-free conditions, where no such conditions exist presently. We identify spatially and temporally explicit ice-free periods that extend beyond what polar bears require for nutritional and reproductive demands. Under business-as-usual climate projections, polar bears may face starvation and reproductive failure across the entire Archipelago by the year 2100.

  13. Projected Polar Bear Sea Ice Habitat in the Canadian Arctic Archipelago

    PubMed Central

    Hamilton, Stephen G.; Castro de la Guardia, Laura; Derocher, Andrew E.; Sahanatien, Vicki; Tremblay, Bruno; Huard, David

    2014-01-01

    Background Sea ice across the Arctic is declining and altering physical characteristics of marine ecosystems. Polar bears (Ursus maritimus) have been identified as vulnerable to changes in sea ice conditions. We use sea ice projections for the Canadian Arctic Archipelago from 2006 – 2100 to gain insight into the conservation challenges for polar bears with respect to habitat loss using metrics developed from polar bear energetics modeling. Principal Findings Shifts away from multiyear ice to annual ice cover throughout the region, as well as lengthening ice-free periods, may become critical for polar bears before the end of the 21st century with projected warming. Each polar bear population in the Archipelago may undergo 2–5 months of ice-free conditions, where no such conditions exist presently. We identify spatially and temporally explicit ice-free periods that extend beyond what polar bears require for nutritional and reproductive demands. Conclusions/Significance Under business-as-usual climate projections, polar bears may face starvation and reproductive failure across the entire Archipelago by the year 2100. PMID:25426720

  14. Multiproxy paleoecological evidence of Holocene climatic changes on the Boothia Peninsula, Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Fortin, Marie-Claude; Gajewski, Konrad

    2016-05-01

    A study of chironomid remains in the sediments of Lake JR01 on the Boothia Peninsula in the Central Canadian Arctic provides a high-resolution record of mean July air temperatures for the last 6.9 ka. Diatom and pollen studies have previously been published from this core. Peak Holocene temperatures occurred prior to 5.0 ka, a time when overall aquatic and terrestrial biological production was high. Chironomid-inferred summer air temperatures reached up to 7.5°C during this period. The region of Lake JR01 cooled over the mid- to late-Holocene, with high biological production between 6.1 and 5.4 ka. Biological production decreased again at ∼2 ka and the rate of cooling increased in the past 2 ka, with coolest temperatures occurring between 0.46 and 0.36 ka, coinciding with the Little Ice Age. Although biological production increased in the last 150 yr, the reconstructed temperatures do not indicate a warming during this time. During transitions, either warming or cooling, chironomid production increases, suggesting an ecosystem-level response to climate variability, seen at a number of lakes across the Arctic.

  15. Exchanges of volume, heat and freshwater through the Canadian Arctic Archipelago: a numerical study.

    NASA Astrophysics Data System (ADS)

    Grivault, Nathan; Hu, Xianmin; Myers, Paul G.

    2016-04-01

    The Canadian Arctic Archipelago (CAA) is a tangle of shallow basins interlinked by narrow straits. It is the main pathway of liquid freshwater from the Arctic Ocean to North Atlantic. It also receives runoff from the Mackenzie River and the glaciers of the different islands that composes the archipelago. This study is based on a set of numerical experiments using a regional configuration of the coupled ocean/sea-ice general circulation model NEMO. We consider a long-term hindcast (1958-2014) as well as the more recent period (2002-2014) using high resolution inter-annual forcing from Environment Canada. We used an improved mapping of runoff to ensure correct amounts of freshwater are added to the system. We evaluate the flow pathways through the CAA, as well as the transport of volume, heat and freshwater. Results are evaluated against observational sections. We also look at the variability and the dynamics driving it. Passive tracers are used to complement the analysis.

  16. Brown snow: A long-range transport event in the Canadian Arctic

    SciTech Connect

    Welch, H.E.; Muir, D.C.G.; Billeck, B.N.; Lockhart, W.L.; Brunskill, G.J.; Kling, H.J. ); Olson, M.P. ); Lemoine, R.M. )

    1991-02-01

    The authors document the occurrence of a long-range transport event that deposited thousands of tons of fine particulates on the District of Keewatin, central Canadian Arctic, {approximately}63 N. Air mass trajectories, clay mineral composition, soot particles, and visible organic remains point to Asian sources for the brown snow material, probably western China. Semivolatile organic pollutants detected in the brown snow included polycyclic aromatic hydrocarbons ({Sigma}PAH), PCB congeners, and DDT-related compounds ({Sigma}DDT), polychlorinated camphenes (PCCs), as well as the herbicide trifuluralin and insecticides methoxychlor, endosulfan, and hexachlorocyclohexane (HCH). {Sigma}PAH, PCB, and PCC concentrations were within the range reported in other studies of Arctic snow but {Sigma}DDT levels were 2-10 times higher than previous reports. High molecular weight PAH may have been associated with soot particles in the brown snow but evidence for Asian sources of the pesticides was not strong because of unknown source signal strengths and possible atmospheric transformations of the compounds. Fluxes of these pollutants were also determined by analyzing sediment cores from two small headwater lakes near the sampling site. The quantities of pollutants deposited in this single event may have comprised a significant fraction (>10%) of total annual input {Sigma}PAH and {Sigma}DDT, as determined from lake sedimentation records.

  17. Invasion, establishment, and range expansion of two parasitic nematodes in the Canadian Arctic.

    PubMed

    Kutz, Susan J; Checkley, Sylvia; Verocai, Guilherme G; Dumond, Mathieu; Hoberg, Eric P; Peacock, Rod; Wu, Jessica P; Orsel, Karin; Seegers, Karin; Warren, Amy L; Abrams, Arthur

    2013-11-01

    Climate warming is occurring at an unprecedented rate in the Arctic and is having profound effects on host-parasite interactions, including range expansion. Recently, two species of protostrongylid nematodes have emerged for the first time in muskoxen and caribou on Victoria Island in the western Canadian Arctic Archipelago. Umingmakstrongylus pallikuukensis, the muskox lungworm, was detected for the first time in 2008 in muskoxen at a community hunt on the southwest corner of the island and by 2012, it was found several hundred kilometers east in commercially harvested muskoxen near the town of Ikaluktutiak. In 2010, Varestrongylus sp., a recently discovered lungworm of caribou and muskoxen was found in muskoxen near Ikaluktutiak and has been found annually in this area since then. Whereas invasion of the island by U. pallikuukensis appears to have been mediated by stochastic movement of muskoxen from the mainland to the southwest corner of the island, Varestrongylus has likely been introduced at several times and locations by the seasonal migration of caribou between the island and the mainland. A newly permissive climate, now suitable for completion of the parasite life cycles in a single summer, likely facilitated the initial establishment and now drives range expansion for both parasites.

  18. Atmospheric mercury in the Canadian Arctic. Part I: a review of recent field measurements.

    PubMed

    Steffen, Alexandra; Lehnherr, Igor; Cole, Amanda; Ariya, Parisa; Dastoor, Ashu; Durnford, Dorothy; Kirk, Jane; Pilote, Martin

    2015-03-15

    Long-range atmospheric transport and deposition are important sources of mercury (Hg) to Arctic aquatic and terrestrial ecosystems. We review here recent progress made in the study of the transport, transformation, deposition and reemission of atmospheric Hg in the Canadian Arctic, focusing on field measurements (see Dastoor et al., this issue for a review of modeling studies on the same topics). Redox processes control the speciation of atmospheric Hg, and thus impart an important influence on Hg deposition, particularly during atmospheric mercury depletion events (AMDEs). Bromine radicals were identified as the primary oxidant of atmospheric Hg during AMDEs. Since the start of monitoring at Alert (NU) in 1995, the timing of peak AMDE occurrence has shifted to earlier times in the spring (from May to April) in recent years, and while AMDE frequency and GEM concentrations are correlated with local meteorological conditions, the reasons for this timing-shift are not understood. Mercury is subject to various post-depositional processes in snowpacks and a large portion of deposited oxidized Hg can be reemitted following photoreduction; how much Hg is deposited and reemitted depends on geographical location, meteorological, vegetative and sea-ice conditions, as well as snow chemistry. Halide anions in the snow can stabilize Hg, therefore it is expected that a smaller fraction of deposited Hg will be reemitted from coastal snowpacks. Atmospheric gaseous Hg concentrations have decreased in some parts of the Arctic (e.g., Alert) from 2000 to 2009 but at a rate that was less than that at lower latitudes. Despite numerous recent advances, a number of knowledge gaps remain, including uncertainties in the identification of oxidized Hg species in the air (and how this relates to dry vs. wet deposition), physical-chemical processes in air, snow and water-especially over sea ice-and the relationship between these processes and climate change.

  19. Novel sulfur-oxidizing streamers thriving in perennial cold saline springs of the Canadian high Arctic.

    PubMed

    Niederberger, Thomas D; Perreault, Nancy N; Lawrence, John R; Nadeau, Jay L; Mielke, Randall E; Greer, Charles W; Andersen, Dale T; Whyte, Lyle G

    2009-03-01

    The perennial springs at Gypsum Hill (GH) and Colour Peak (CP), situated at nearly 80 degrees N on Axel Heiberg Island in the Canadian high Arctic, are one of the few known examples of cold springs in thick permafrost on Earth. The springs emanate from deep saline aquifers and discharge cold anoxic brines rich in both sulfide and sulfate. Grey-coloured microbial streamers form during the winter months in snow-covered regions of the GH spring run-off channels (-1.3 degrees C to 6.9 degrees C, approximately 7.5% NaCl, 0-20 p.p.m. dissolved sulfide, 1 p.p.m. dissolved oxygen) but disappear during the Arctic summer. Culture- and molecular-based analyses of the 16S rRNA gene (FISH, DGGE and clone libraries) indicated that the streamers were uniquely dominated by chemolithoautotrophic sulfur-oxidizing Thiomicrospira species. The streamers oxidized both sulfide and thiosulfate and fixed CO(2) under in situ conditions and a Thiomicrospira strain isolated from the streamers also actively oxidized sulfide and thiosulfate and fixed CO(2) under cold, saline conditions. Overall, the snow-covered spring channels appear to represent a unique polar saline microhabitat that protects and allows Thiomicrospira streamers to form and flourish via chemolithoautrophic, phototrophic-independent metabolism in a high Arctic winter environment characterized by air temperatures commonly below -40 degrees C and with an annual average air temperature of -15 degrees C. These results broaden our knowledge of the physical and chemical boundaries that define life on Earth and have astrobiological implications for the possibility of life existing under similar Martian conditions.

  20. Landfast ice thickness in the Canadian Arctic Archipelago from observations and models

    NASA Astrophysics Data System (ADS)

    Howell, Stephen E. L.; Laliberté, Frédéric; Kwok, Ron; Derksen, Chris; King, Joshua

    2016-07-01

    Observed and modelled landfast ice thickness variability and trends spanning more than 5 decades within the Canadian Arctic Archipelago (CAA) are summarized. The observed sites (Cambridge Bay, Resolute, Eureka and Alert) represent some of the Arctic's longest records of landfast ice thickness. Observed end-of-winter (maximum) trends of landfast ice thickness (1957-2014) were statistically significant at Cambridge Bay (-4.31 ± 1.4 cm decade-1), Eureka (-4.65 ± 1.7 cm decade-1) and Alert (-4.44 ± 1.6 cm -1) but not at Resolute. Over the 50+-year record, the ice thinned by ˜ 0.24-0.26 m at Cambridge Bay, Eureka and Alert with essentially negligible change at Resolute. Although statistically significant warming in spring and fall was present at all sites, only low correlations between temperature and maximum ice thickness were present; snow depth was found to be more strongly associated with the negative ice thickness trends. Comparison with multi-model simulations from Coupled Model Intercomparison project phase 5 (CMIP5), Ocean Reanalysis Intercomparison (ORA-IP) and Pan-Arctic Ice-Ocean Modeling and Assimilation System (PIOMAS) show that although a subset of current generation models have a "reasonable" climatological representation of landfast ice thickness and distribution within the CAA, trends are unrealistic and far exceed observations by up to 2 orders of magnitude. ORA-IP models were found to have positive correlations between temperature and ice thickness over the CAA, a feature that is inconsistent with both observations and coupled models from CMIP5.

  1. Late Cretaceous Extreme Polar Warmth recorded by Vertebrate Fossils from the High Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Vandermark, D.; Tarduno, J. A.; Brinkman, D.

    2006-12-01

    A vertebrate fossil assemblage from Late Cretaceous (Coniacian-Turonian, ~92 to 86 Ma) rocks on Axel Heiberg Island in the High Canadian Arctic reflects what was once a diverse community of freshwater fishes and reptiles. Paleomagnetic data indicate a paleolatitude of ~71° N for the site; the fossils are from non-migratory fauna, so they can provide insight into Late Cretaceous polar climate. The fossil assemblage includes large (> 2.4 m long) champsosaurs (extinct crocodilelike reptiles). The presence of large champsosaurs suggests a mean annual temperature > 14 °C (and perhaps as great as 25 °C). Here we summarize findings and analyses following the discovery of the fossil-bearing strata in 1996. Examination of larger fish elements, isolated teeth and SEM studies of microstructures indicates the presence of lepisosteids, amiids and teleosts (Friedman et al., 2003) Interestingly, the only other known occurrence of amiids and lepisosteids, fossil or recent, are from intervals of extreme warmth during the Tertiary. Turtles present in the assemblage include Boreralochelys axelheibergensis, a generically indeterminate eucryptodire and a trioychid (Brinkman and Tarduno, 2005). The level of turtle diversity is also comparable to mid-latitude assemblages with a mean annual paleotemperature of at least 14 °C. A large portion of the champsosaur fossil assemblage is comprised of elements from subadults. This dominance of subadults is similar to that seen from low latitude sites. Because of the sensitivity of juveniles to ice formation, the make-up of the Arctic champsosaur population further indicates that the Late Cretaceous saw an interval of extreme warmth and low seasonality. We note the temporal coincidence of these fossils with volcanism at large igneous provinces (including high Arctic volcanism) and suggest that a pulse in volcanic carbon dioxide emissions helped cause the global warmth.

  2. Persistent organic pollutants and diabetes among Inuit in the Canadian Arctic.

    PubMed

    Singh, Kavita; Chan, Hing Man

    2017-02-12

    Type 2 diabetes is a chronic metabolic disease that is of increasing concern in Inuit communities. Behavioural factors such as physical inactivity and poor diet are well-known risk factors. Exposure to persistent organic pollutants (POPs) has emerged as an additional factor in the pathogenesis of diabetes. In this study, association between polychlorinated biphenyls (PCBs) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) with diabetes in Canadian Inuit was examined. Data from the Adult Inuit Health Survey (2007-2008) of Inuit participants from the Canadian Arctic were analyzed. Self-reported diabetes (excluding gestational diabetes) and clinical measurement of fasting glucose were examined as outcomes. Association with individual PCB congeners, sum of dioxin-like PCBs (∑DL-PCB), non-dioxin-like PCBs (∑NDL-PCB), total PCBs (∑PCB), and p,p'-DDE were investigated using multiple regression models adjusted for confounding factors. Using different methods to incorporate serum lipids, highest vs. lowest quartile exposures to PCB-105, PCB-118, PCB-153, PCB-156, PCB-170, PCB-180, PCB-183, ∑PCB, and p,p'-DDE were associated with increased risk of diabetes. For these PCBs, odds ratios (ORs) ranged from 1.9-3.5 (lower 95% CI: 0.8-1.4, upper 95% CI: 4.4-9.0) and for p,p'-DDE the OR was 2.5 (lower 95% CI: 1.1-1.2, upper 95% CI: 5.9-6.0). The highest vs. lowest quartile exposure to most PCBs and p,p'-DDE were associated with an increase of fasting glucose by 3-7%. PCBs and p,p'-DDE were associated with increased risk of diabetes and higher fasting glucose level in a cross-sectional survey of Canadian Inuit. Cause-effect relationships of PCBs and p,p'-DDE with diabetes and diabetes-related outcomes need to be further investigated in a cohort study.

  3. Sources of Dimethyl Sulfide in the Canadian Arctic Archipelago and Baffin Bay

    NASA Astrophysics Data System (ADS)

    Mungall, E. L.; Croft, B.; Lizotte, M.; Thomas, J. L.; Murphy, J. G.; Levasseur, M.; Martin, R.; Wentzell, J. J. B.; Liggio, J.; Abbatt, J.

    2015-12-01

    Dimethyl sulfide plays a major role in the global sulfur cycle, meaning that it is important to the formation of sulfate aerosol and thus to cloud condensation nuclei populations and cloud formation. The summertime Arctic atmosphere sometimes resides in a cloud condensation nuclei limited regime, making it very susceptible to changes in their number. Despite the interest generated by this situation, dimethyl sulfide has only rarely been measured in the summertime Arctic. This work presents the first high time resolution (10 Hz) DMS mixing ratio measurements for the Eastern Canadian Archipelago and Baffin Bay in summer performed on an icebreaker cruise as one component of the Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments (NETCARE). Measured mixing ratios ranged from below the detection limit of 4 pptv to 1155 pptv with a median value of 186 pptv. We used transfer velocity parameterizations from the literature to generate the first flux estimates for this region in summer, which ranged from 0.02-12 μmol m-2 d-1. DMS has a lifetime against OH oxidation of 1-2 days, allowing both local sources and transport to play roles in its atmospheric mixing ratio. Through air mass trajectory analysis using FLEXPART-WRF and chemical transport modeling using GEOS-Chem, we have identified the relative contributions of local sources (Lancaster Sound and Baffin Bay) as well as transport from further afield (the Hudson Bay System and the Beaufort Sea) and find that the local sources dominate. GEOS-Chem is able to reproduce the major features of the measured time series, but is biased low overall (median 72 pptv). We discuss non-marine sources that could account for this low bias and estimate the possible contributions to DMS mixing ratios from lakes, biomass burning, melt ponds and coastal tundra. Our results show that local marine sources of DMS dominate the summer Arctic atmosphere, but that non-local and possibly non

  4. Identification of long-chain perfluorinated acids in biota from the Canadian Arctic.

    PubMed

    Martin, Jonathan W; Smithwick, Marla M; Braune, Birgit M; Hoekstra, Paul F; Muir, Derek C G; Mabury, Scott A

    2004-01-15

    Recently it was discovered that humans and animals from various urban and remote global locations contained a novel class of persistent fluorinated contaminants, the most pervasive of which was perfluorooctane sulfonate (PFOS). Lower concentrations of perfluorooctanoate, perfluorohexane sulfonate, and heptadecafluorooctane sulfonamide have also been detected in various samples. Although longer perfluoroalkyl carboxylates (PFCAs) are used in industry and have been detected in fish following a spill of aqueous film forming foam, no studies have been conducted to examine the widespread occurrence of long-chain PFCAs (e.g., CF3(CF2)xCOO-, where x > 6). To provide a preliminary assessment of fluorinated contaminants, including PFCAs, in the Canadian Arctic, polar bears, ringed seals, arctic fox, mink, common loons, northern fulmars, black guillemots, and fish were collected at various locations in the circumpolar region. PFOS was the major contaminant detected in most samples and in polar bear liver was the most prominent organohalogen (mean PFOS = 3.1 microg/g wet weight) compared to individual polychlorinated biphenyl congeners, chlordane, or hexachlorocyclohexane-related chemicals in fat. Using two independent mass spectral techniques, it was confirmed that all samples also contained ng/g concentrations of a homologous series of PFCAs, ranging in length from 9 to 15 carbons. Sum concentrations of PFCAs (sum(PFCAs)) were lower than total PFOS equivalents (sum(PFOS)) in all samples except for mink. In mink, perfluorononanoate (PFNA) concentrations exceeded PFOS concentrations, indicating that PFNA and other PFCAs should be considered in future risk assessments. Mammals feeding at higher trophic levels had greater concentrations of PFOS and PFCAs than mammals feeding at lower trophic positions. In general, odd-length PFCAs exceeded the concentration of even-length PFCAs, and concentrations decreased with increasing chain length in mammals. PFOS and PFCA concentrations

  5. Response of Biogeochemical Processes to Recent Sea Ice Decreasing in Arctic Chukchi Sea and Canadian Basin

    NASA Astrophysics Data System (ADS)

    Chen, J.; Jin, H.; Li, H.; Liu, Z.; Zhang, H.

    2009-04-01

    Because of its sea ice cover the Arctic Ocean has not been considered as a sink of atmospheric carbon dioxide. With recent observations of decreasing ice cover due to global warming there is the potential for an increasing of biological pump efficiency, especially in Arctic Chukchi Sea and Canadian Basin where upper ocean nutrients transported from Bering Sea are very abundant. During three Icebreaker Xuelong cruises of Chinese Arctic Expeditions in summers in 1999, 2003 and 2008, we analyzed nutrients, DO, chl a, opal, primary productivity and carried out nutrients enrichment experiments on board. The results showed that sea ice in summer decreased very rapidly since 1999. Silicate and nitrate were largely depleted along the 170°W longitude section from Bering Strait to Canadian Basin while phosphate was over 0.5μM in most areas during three cruises, with a slight decadal decrease trend of nutrients suggesting uptake increase due to longer open ocean period within a year. Nutrients enrichment experiments suggested that there was silicate and nitrate co-limitation in central Canadian Basin in summer 2008 where only 10-20% sea ice cover. Average water column chl a concentrations were 2.79, 2.42 and 2.89 μg/L in 1999, 2003 and 2008 respectively with the chl a maximum at depth between 20-40m in shelf area and 20-70m in deep basin. Interestingly, chl a maximum became deeper in early September than it in late July along the 170°W section in 2003 and 2008, suggesting subsurface nutrients would also be utilized when upper ocean nutrients was depleted. The size fraction analysis of chl a showed that about 70% of chl a was contributed by >20μ phytoplankton while nano- and pico- plankton were minor contributors. Size fraction of opal analysis (>20μ and 0.8-20μ) in water column also supported that large phytoplankton predominated. The active biological pump in water column lead to higher chl a concentration in multicore sediments, highest sedimentary chl a (core top, 0

  6. Shipboard measurement of atmospheric DMS and its oxidation products over the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Rempillo, O. T.; Seguin, A.; Norman, A. L.

    2009-12-01

    We measured atmospheric Dimethyl Sulphide (DMS), a compound released by phytoplankton, and its major oxidation products in the atmosphere during Fall 2007 and Fall 2008 in the Canadian Arctic as part of the joint Arctic SOLAS-Arcticnet-CFL field campaign. DMS is the major source of biogenic sulphate in the remote marine atmosphere and is hypothesized to provide a biological climate feedback that could stabilize the Earth’s temperature in the event of a warming episode by the production of sulphate aerosols and cloud condensation nuclei (CCN) (Charlson et.al., 1987). We obtained DMS measurements ranging from below detection limit of around 0.3 nmol/m3 to a maximum of 4.2 nmol/m3 for Fall 2007 and 12.5 nmol/m3 for Fall 2008. DMS exhibited a general trend of decreasing concentration further into the season and with increasing ice cover. Concentrations of atmospheric sulphur compounds are as follows: Sulphur dioxide [SO2] = 2.7-135 nmol/m3 (2007) and 0.28-27 nmol/m3 (2008), Methanesulfonic acid [MSA] = 0.03-0.07 nmol/m3 (2007) and 0.02-0.14 nmol/m3 (2008), and non-seasalt Sulphate [nSS-SO42-] = 0.48-6.9 nmol/m3 (2007) and 0.01-2.0 nmol/m3 (2008). DMS oxidation is not the only source of SO2 and SO42- in the Arctic. δ34S of the samples are consistent for a mixture of sea-salt (+21‰), anthropogenic (ship fuel, +3‰), biogenic sulphate (+18‰) and a source of negative δ34S values between -10‰ to -30‰, particularly in the western Arctic. We used δ34S to apportion the amount of SO2 and SO42- derived from DMS oxidation. We found biogenic SO2 and SO42- concentrations to be approximately 0-115 nmol/m3 and 0-2.5 nmol/m3 respectively for 2007 and approximately 0-19 nmol/m3 and 0-0.8 nmol/m3 respectively for 2008. These results are important inputs in modelling DMS oxidation, determining the effects of its oxidation products to aerosol formation and ascertaining possible climatic effects. R. Charlson, J. Lovelock, M. Andreae and S. Warren (1987). Oceanic phytoplankton

  7. The US - Canadian natural gas relationship: at the crossroads

    SciTech Connect

    Burns, D.H.

    1983-06-01

    US-Canada natural gas relationships reached an important juncture in early 1983. Pressure to oblige Canada to lower its gas export prices built up in the face of Canada's policy to let the status quo, in which Canada has all time high earnings, stand. The difficulties are caused by the Duncan-Lalonde understanding on Canada's substitution price formula, the uniform border price, and the take-or-pay clauses in US-Canadian contracts. These features lead to an exceedingly rigid system insensitive to market signals. A DOE conference on January 18, 1983, indicated that gas importers think that import prices are too high, and want a pricing scheme that would permit buyers and sellers to negotiate prices. A new system which is market sensitive and flexible with minimal government interference must replace the current system.

  8. Persistent organic pollutants and mercury in marine biota of the Canadian Arctic: an overview of spatial and temporal trends.

    PubMed

    Braune, B M; Outridge, P M; Fisk, A T; Muir, D C G; Helm, P A; Hobbs, K; Hoekstra, P F; Kuzyk, Z A; Kwan, M; Letcher, R J; Lockhart, W L; Norstrom, R J; Stern, G A; Stirling, I

    2005-12-01

    This review summarizes and synthesizes the significant amount of data which was generated on mercury (Hg) and persistent organic pollutants (POPs) in Canadian Arctic marine biota since the first Canadian Arctic Contaminants Assessment Report (CACAR) was published in 1997. This recent body of work has led to a better understanding of the current levels and spatial and temporal trends of contaminants in biota, including the marine food species that northern peoples traditionally consume. Compared to other circumpolar countries, concentrations of many organochlorines (OCs) in Canadian Arctic marine biota are generally lower than in the European Arctic and eastern Greenland but are higher than in Alaska, whereas Hg concentrations are substantially higher in Canada than elsewhere. Spatial coverage of OCs in ringed seals, beluga and seabirds remains a strength of the Arctic contaminant data set for Canada. Concentrations of OCs in marine mammals and seabirds remain fairly consistent across the Canadian Arctic although subtle differences from west to east and south to north are found in the proportions of various chemicals. The most significant development since 1997 is improvement in the temporal trend data sets, thanks to the use of archived tissue samples from the 1970s and 1980s, long-term studies using archeological material, as well as the continuation of sampling. These data cover a range of species and chemicals and also include retrospective studies on new chemicals such as polybrominated diphenyl ethers. There is solid evidence in a few species (beluga, polar bear, blue mussels) that Hg at some locations has significantly increased from pre-industrial times to the present; however, the temporal trends of Hg over the past 20-30 years are inconsistent. Some animal populations exhibited significant increases in Hg whereas others did not. Therefore, it is currently not possible to determine if anthropogenic Hg is generally increasing in Canadian Arctic biota. It is

  9. Changes in driftwood delivery to the Canadian Arctic Archipelago: The hypothesis of postglacial oscillations of the transpolar drift

    USGS Publications Warehouse

    Dyke, A.S.; England, J.; Reimnitz, E.; Jette, H.

    1997-01-01

    Driftwood appears to be absent in the Beaufort Gyre but abundant in parts of the Transpolar Drift (TPD), which crosses the Arctic Ocean from the Chukchi Sea to the vicinity of northeastern Greenland. Nearly 300 radiocarbon dates on Holocene driftwood from the Canadian Arctic Archipelago reveal two regions with contrasting histories of driftwood incursion: the region accessible to wood brought into Baffin Bay by the West Greenland Current and the rest of the archipelago, which receives wood from the Arctic Ocean. We hypothesize that when the TPD was deflected westward along northern Greenland, wood was delivered widely to the Canadian Arctic Archipelago; when the TPD exited entirely through Fram Strait via the East Greenland Current, little or no wood was delivered to most of the archipelago, but some continued into Baffin Bay via the West Greenland Current. A split TPD delivered wood to both regions. The regional driftwood incursion histories exhibit multiple maxima and minima that can be explained by this hypothesis. The Larix to Picea ratio of wood arriving in the Canadian Arctic Archipelago has also changed through time. This may indicate varying contributions from Russian versus North American sources, which in turn may indicate variable mixing of wood en route. The inferred discharge paths of the TPD were apparently stable for intervals ranging from several millennia to centuries or perhaps only decades. The last major switch broadly correlates with the onset of Neoglaciation. Variations in the path and strength of the TPD may have important oceanographic and climatic consequences downstream in the North Atlantic Ocean.

  10. Undiscovered Arctic gas hydrates: permafrost relationship and resource evaluation.

    NASA Astrophysics Data System (ADS)

    Cherkashov, G. A.; Matveeva, T.

    2011-12-01

    Though ice-core studies show that multidecadal-scale methane variability is only weakly correlated with reconstructed temperature variations (Mitchell et al., 2010) methane emission to the atmosphere still consider as the most significant contributions to the global warming processes. Pockmarks, seeps, mud volcanoes and other features associated with methane fluxes from the seabed have been widely reported, particularly during the last three decades. On continental margins, seepage of hydrocarbon gases from shallow sedimentary layers is a common phenomenon, resulting either from in situ formation of gases (mainly methane) by bacterial decomposition of organic matter within rapidly accumulated upper sediments or from upward migration of gases formed at greater depths. Furthermore, processes associated with seabed fluid flow have been shown to affect benthic ecology and to supply methane to the hydrosphere and the atmosphere (Judd, 2003; Hovland and Judd, 2007). The most recent investigations testified that revaluation of the role of gas seeps and related gas hydrate formation processes in the Arctic environment is necessary for the understanding of global methane balance and global climate changes (Westbrook et al., 2009; Shahova and Semiletov, 2010). With respect to gas hydrate formation, due to the presence of relict permafrost the Arctic submarine environment holds a specific place that is distinct from the rest of the Ocean. Submarine gas hydrates in the Arctic may be confined to (1) relict permafrost occurrences on the shelf; (2) concentrated methane infiltration toward the seafloor (shallow-seated gas hydrates); (3) dissipated methane infiltration from great depths (deep-seated gas hydrates). Permafrost-related or cryogenic gas hydrates form due to exogenous cooling of sediment (intra- and sub-permafrost gas hydrates). It is also suggested that some parts of hydrates may be preserved owing to a self-preservation effect above the gas hydrate stability zone

  11. Resource utilisation by deep-sea megabenthos in the Canadian High Arctic (Baffin Bay and Parry Channel)

    NASA Astrophysics Data System (ADS)

    Bourgeois, Solveig; Witte, Ursula; Harrison, Ailish M.; Makela, Anni; Kazanidis, Georgios; Archambault, Philippe

    2016-04-01

    Ongoing climate change in the Arctic is causing drastic alteration of the Arctic marine ecosystem functioning, such as shifts in patterns of primary production, and modifying the present tight pelagic-benthic coupling. Subsequently benthic communities, which rely upon organic matter produced in the top layers of the Ocean, will also be affected by these changes. The benthic megafaunal communities play a significant role in ecological processes and ecosystem functioning (i.e. organic matter recycling, bioturbation, food source for the higher trophic levels…). Yet, information is scarce regarding the main food sources for dominant benthic organisms, and therefore the impact of the ongoing changes is difficult to assess. The goal of this study is to investigate the preferential feeding of different carbon sources by megabenthic organisms in the Canadian High Arctic and to identify environmental drivers which explain the observed trends. In summer 2013, benthic megafauna was collected at 9 stations spread along latitudinal (58 to 81°N) and longitudinal (62 to 114°W) transects in the Baffin Bay and Parry Channel, respectively. Carbon and nitrogen bulk stable isotope analyses (δ13C and δ15N) were performed on several species divided into groups according to their feeding type. This study highlights distinct trends in δ13C values of benthic organisms suggesting the importance of both phytoplankton and ice algae as carbon sources for megafauna in the Canadian High Arctic. The importance of physical and biological parameters as drivers of food web structure will be furthermore discussed.

  12. Climate change impacts on continental weathering through the Middle Jurassic to Lower Cretaceous of Sverdrup Basin, Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Galloway, Jennifer; Grasby, Stephen; Swindles, Graeme; Dewing, Keith

    2014-05-01

    Jurassic to Cretaceous strata of Sverdrup Basin, Canadian Arctic Archipelago, contain marine and non-marine successions that can be studied to reconstruct ancient paleoclimates and paleoenvironments that are poorly understood in high-latitude regions. We use element geochemistry integrated with palynology to study a continuous Aalenian to Albian-aged succession preserved in the Hoodoo Dome H-37 oil and gas well located on southern Ellef Ringnes Island near the centre of Sverdrup Basin. Cluster analysis (stratigraphically constrained incremental sum of squares; CONISS) is used to delineate four geochemical zones that are broadly coeval with major changes in palyno-assemblages interpreted to reflect changes in regional paleoclimate. Zone 1 (late Aalenian to Bathonian) is characterized by palynomorphs associated with humid and warm climate conditions. The chemical alteration index (CAI) is high in this interval, expected under this a humid and warm climate. A transition to a seasonally arid and warm climate occurred in the Bathonian and persisted until the Kimmeridgian or Valanginian (Zone 2). This interval is characterized by decreased chemical weathering, indicated by a drop in CAI. The onset of Zone 3 (Kimmeridgian or Valanginian to late Barremian or early Aptian) occurs during a transition to humid and cool climate conditions and is associated with a period of regional uplift and rifting. Zone 3 is marked by a substantial and progressive drop in CAI, indicating a transition from a weathering to transport-dominated system, possibly associated with landscape destabilization. Reduced tectonic activity in Zone 4 (early Aptian to early or mid Albian) shows a return to active chemical weathering, possibly associated with landscape stabilization, suggested by a continued increase in pollen from upland coniferous taxa. The geochemical and palynological records of Middle Jurassic to Lower Cretaceous strata of the Hoodoo Dome H-37 oil and gas well show close correlation

  13. DNA barcoding the Canadian Arctic flora: core plastid barcodes (rbcL + matK) for 490 vascular plant species.

    PubMed

    Saarela, Jeffery M; Sokoloff, Paul C; Gillespie, Lynn J; Consaul, Laurie L; Bull, Roger D

    2013-01-01

    Accurate identification of Arctic plant species is critical for understanding potential climate-induced changes in their diversity and distributions. To facilitate rapid identification we generated DNA barcodes for the core plastid barcode loci (rbcL and matK) for 490 vascular plant species, representing nearly half of the Canadian Arctic flora and 93% of the flora of the Canadian Arctic Archipelago. Sequence recovery was higher for rbcL than matK (93% and 81%), and rbcL was easier to recover than matK from herbarium specimens (92% and 77%). Distance-based and sequence-similarity analyses of combined rbcL + matK data discriminate 97% of genera, 56% of species, and 7% of infraspecific taxa. There is a significant negative correlation between the number of species sampled per genus and the percent species resolution per genus. We characterize barcode variation in detail in the ten largest genera sampled (Carex, Draba, Festuca, Pedicularis, Poa, Potentilla, Puccinellia, Ranunculus, Salix, and Saxifraga) in the context of their phylogenetic relationships and taxonomy. Discrimination with the core barcode loci in these genera ranges from 0% in Salix to 85% in Carex. Haplotype variation in multiple genera does not correspond to species boundaries, including Taraxacum, in which the distribution of plastid haplotypes among Arctic species is consistent with plastid variation documented in non-Arctic species. Introgression of Poa glauca plastid DNA into multiple individuals of P. hartzii is problematic for identification of these species with DNA barcodes. Of three supplementary barcode loci (psbA-trnH, psbK-psbI, atpF-atpH) collected for a subset of Poa and Puccinellia species, only atpF-atpH improved discrimination in Puccinellia, compared with rbcL and matK. Variation in matK in Vaccinium uliginosum and rbcL in Saxifraga oppositifolia corresponds to variation in other loci used to characterize the phylogeographic histories of these Arctic-alpine species.

  14. Aerosol Size and Chemical Composition in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Chang, R. Y. W.; Hayes, P. L.; Leaitch, W. R.; Croft, B.; O'Neill, N. T.; Fogal, P.; Drummond, J. R.; Sloan, J. J.

    2015-12-01

    Arctic aerosol have a strong annual cycle, with winter months dominated by long range transport from lower latitudes resulting in high mass loadings. Conversely, local emissions are more prominent in the summer months because of the decreased influence of transported aerosol, allowing us to regularly observe both transported and local aerosol. This study will present observations of aerosol chemical composition and particle number size distribution collected at the Polar Environment Artic Research Laboratory and the Alert Global Atmospheric Watch Observatory at Eureka (80N, 86W) and Alert (82N, 62W), Nunavut, respectively. Summer time observations of the number size distribution reveal a persistent mode of particles centered between 30-50 nm, with occasional bursts of smaller particles. The non-refractory aerosol chemical composition, measured by the Canadian Network for the Detection of Atmospheric Change quadrupole aerosol mass spectrometer, is primarily organic, with contributions from both aged and fresher organic aerosol. Factor analysis will be conducted to better understand these sources. The site at Eureka is more susceptible to long range transport since it is at the top of a mountain ridge (610 m above sea level) and will be compared to the site at Alert on an elevated plain (200 m above sea level). This will allow us to determine the relative contributions from processes and sources at the sites at different elevations. Comparisons with aerosol optical depth and GEOS-Chem model output will also be presented to put these surface measurements into context with the overlying and regional atmosphere. Results from this study contribute to our knowledge of aerosol in the high Arctic.

  15. Evaluation of Icebridge Snow Radar Measurements over Sea Ice in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Derksen, C.; King, J. M.; Howell, S.; Toose, P.; Silis, A.; Rutter, N.

    2014-12-01

    Recent efforts to retrieve snow depth on sea ice using the Operation IceBridge (OIB) snow radar have identified uncertainties related to the vertical heterogeneity of snow, ice deformation, and radar side lobes (e.g. Farrell, et. Al., 2012, Kurtz et. Al., 2013, Kwok and Maksym, 2014). To characterize and evaluate snow depth retrieval uncertainties as related to snow physical properties, an OIB mission was flown near Eureka, Nunavut (79°59'20"N, 85°56'27"W) within the Canadian Arctic archipelago as part of the 2014 OIB Arctic campaign. A series of 12 parallel flight lines covered a narrow swath of first year sea ice approximately 50 km in length. Immediately following the OIB mission, an intensive 10-day field campaign was completed to characterize snow and ice properties within the footprint of the OIB snow radar at multiple scales. Measurements were divided between two observation areas: (1) a primary sampling transect along the length of the flights to characterize horizontal variability in bulk snow properties and (2) a set of intensive grids (250 m x 250) to evaluate variations in snow properties sub-grid to OIB products. As part of each experiment, standard sampling methods were used to collect geo-located snow depth and snow pit measurements (stratigraphy, density, grain size, and salinity). More than 30,000 geo-located snow depth measurements were collected along the primary transect with 94% located within the snow radar footprint. The substantial volume of field measurements coincident with OIB snow radar observations provides an excellent opportunity to evaluate and advance the retrieval of radar-derived snow depth over sea ice. In this study, we present statistical analysis of the observed radar signal and measured snow properties at multiple scales to address previously identified ambiguities in the interpretation of the radar returns.

  16. Postglacial response of Arctic Ocean gas hydrates to climatic amelioration

    NASA Astrophysics Data System (ADS)

    Serov, Pavel; Vadakkepuliyambatta, Sunil; Mienert, Jürgen; Patton, Henry; Portnov, Alexey; Silyakova, Anna; Panieri, Giuliana; Carroll, Michael L.; Carroll, JoLynn; Andreassen, Karin; Hubbard, Alun

    2017-06-01

    Seafloor methane release due to the thermal dissociation of gas hydrates is pervasive across the continental margins of the Arctic Ocean. Furthermore, there is increasing awareness that shallow hydrate-related methane seeps have appeared due to enhanced warming of Arctic Ocean bottom water during the last century. Although it has been argued that a gas hydrate gun could trigger abrupt climate change, the processes and rates of subsurface/atmospheric natural gas exchange remain uncertain. Here we investigate the dynamics between gas hydrate stability and environmental changes from the height of the last glaciation through to the present day. Using geophysical observations from offshore Svalbard to constrain a coupled ice sheet/gas hydrate model, we identify distinct phases of subglacial methane sequestration and subsequent release on ice sheet retreat that led to the formation of a suite of seafloor domes. Reconstructing the evolution of this dome field, we find that incursions of warm Atlantic bottom water forced rapid gas hydrate dissociation and enhanced methane emissions during the penultimate Heinrich event, the Bølling and Allerød interstadials, and the Holocene optimum. Our results highlight the complex interplay between the cryosphere, geosphere, and atmosphere over the last 30,000 y that led to extensive changes in subseafloor carbon storage that forced distinct episodes of methane release due to natural climate variability well before recent anthropogenic warming.

  17. Postglacial response of Arctic Ocean gas hydrates to climatic amelioration.

    PubMed

    Serov, Pavel; Vadakkepuliyambatta, Sunil; Mienert, Jürgen; Patton, Henry; Portnov, Alexey; Silyakova, Anna; Panieri, Giuliana; Carroll, Michael L; Carroll, JoLynn; Andreassen, Karin; Hubbard, Alun

    2017-06-13

    Seafloor methane release due to the thermal dissociation of gas hydrates is pervasive across the continental margins of the Arctic Ocean. Furthermore, there is increasing awareness that shallow hydrate-related methane seeps have appeared due to enhanced warming of Arctic Ocean bottom water during the last century. Although it has been argued that a gas hydrate gun could trigger abrupt climate change, the processes and rates of subsurface/atmospheric natural gas exchange remain uncertain. Here we investigate the dynamics between gas hydrate stability and environmental changes from the height of the last glaciation through to the present day. Using geophysical observations from offshore Svalbard to constrain a coupled ice sheet/gas hydrate model, we identify distinct phases of subglacial methane sequestration and subsequent release on ice sheet retreat that led to the formation of a suite of seafloor domes. Reconstructing the evolution of this dome field, we find that incursions of warm Atlantic bottom water forced rapid gas hydrate dissociation and enhanced methane emissions during the penultimate Heinrich event, the Bølling and Allerød interstadials, and the Holocene optimum. Our results highlight the complex interplay between the cryosphere, geosphere, and atmosphere over the last 30,000 y that led to extensive changes in subseafloor carbon storage that forced distinct episodes of methane release due to natural climate variability well before recent anthropogenic warming.

  18. Hospital admissions for lower respiratory tract infections among infants in the Canadian Arctic: a cohort study

    PubMed Central

    Banerji, Anna; Panzov, Val; Young, Michael; Robinson, Joan; Lee, Bonita; Moraes, Theo; Mamdani, Muhammad; Giles, B. Louise; Jiang, Depeng; Bisson, Danny; Dennis, Marguerite; Morel, Johanne; Hall, Judith; Hui, Charles; Paes, Bosco; Mahony, James B.

    2016-01-01

    Background: It is unknown whether this burden of disease of lower respiratory tract infections is comparable across the Canadian Arctic. The objectives of this surveillance study were to compare the rates of hospital admission for lower respiratory tract infection and the severity of infection across Arctic Canada, and to describe the responsible viruses. Methods: We performed a prospective multicentre surveillance study of infants less than 1 year of age admitted in 2009 with lower respiratory tract infection to all hospitals (5 regional, 4 tertiary) in the Northwest Territories, Nunavut and Nunavik to assess for regional differences. Nasopharyngeal aspirates were processed by means of a polymerase chain reaction respiratory viral panel, testing for 20 respiratory viruses and influenza A (H1N1). The role of coinfection was assessed by means of regression analysis for length of stay (short: < 7 d; long: > 14 d). Outcomes compared included rates of lower respiratory tract infection, respiratory syncytial virus infection, transfer to tertiary hospital and severe lower respiratory tract infection (respiratory failure, intubation and mechanical ventilation, and/or cardiopulmonary resuscitation). Results: There were 348 admissions for lower respiratory tract infection in the population of interest in 2009. Rates of admission per 1000 live births varied significantly, from 39 in the Northwest Territories to 456 in Nunavik (p < 0.001). The rates of tertiary admissions and severe lower respiratory tract infection per 1000 live births in the Northwest Territories were 5.6 and 1.4, respectively, compared to 55.9 and 17.1, respectively, in Nunavut and 52.0 and 20.0, respectively, in Nunavik (p ≤ 0.001). Respiratory syncytial virus was the most common virus identified (124 cases [41.6% of those tested]), and coinfection was detected in 51 cases (41.1%) of infection with this virus. Longer length of stay was associated with coinfection (odds ratio [OR] 2.64) and underlying

  19. Methylated mercury species in Canadian high Arctic marine surface waters and snowpacks.

    PubMed

    St Louis, Vincent L; Hintelmann, Holger; Graydon, Jennifer A; Kirk, Jane L; Barker, Joel; Dimock, Brian; Sharp, Martin J; Lehnherr, Igor

    2007-09-15

    We sampled seawater and snowpacks in the Canadian high Arctic for methylated species of mercury (Hg). We discovered that, although seawater sampled under the sea ice had very low concentrations of total Hg (THg, all forms of Hg in a sample; on average 0.14-0.24 ng L(-1)), 30-45% of the THg was in the monomethyl Hg (MMHg) form (on average 0.057-0.095 ng L(-1)), making seawater itself a direct source of MMHg for biomagnification through marine food webs. Seawater under the ice also contained high concentrations of gaseous elemental Hg (GEM; 129 +/- 36 pg L(-1)), suggesting that open water regions such as polynyas and ice leads were a net source of approximately 130 +/- 30 ng Hg m(-2) day(-1) to the atmosphere. We also found 11.1 +/- 4.1 pg L(-1) of dimethyl Hg (DMHg) in seawater and calculated that there could be a significant flux of DMHg to the atmosphere from open water regions. This flux could then resultin MMHg deposition into nearby snowpacks via oxidation of DMHg to MMHg in the atmosphere. In fact, we found high concentrations of MMHg in a few snowpacks near regions of open water. Interestingly, we discovered a significant log-log relationship between Cl- concentrations in snowpacks and concentrations of THg. We hypothesize that as Cl- concentrations in snowpacks increase, inorganic Hg(II) occurs principally as less reducible chloro complexes and, hence, remains in an oxidized state. As a result, snowpacks that receive both marine aerosol deposition of Cl- and deposition of Hg(II) via springtime atmospheric Hg depletion events, for example, may contain significant loads of Hg(II). Overall, though, the median wet/dry loads of Hg in the snowpacks we sampled in the high Arctic (5.2 mg THg ha(-1) and 0.03 mg MMHg ha(-1)) were far below wet-only annual THg loadings throughout southern Canada and most of the U.S. (22-200 mg ha(-1)). Therefore, most Arctic snowpacks contribute

  20. Body burden of metals and persistent organic pollutants among Inuit in the Canadian Arctic.

    PubMed

    Laird, Brian D; Goncharov, Alexey B; Chan, Hing Man

    2013-09-01

    Inuit living in the Arctic are exposed to elevated levels of environmental contaminants primarily due to long-range atmospheric transport. Blood sampling and contaminant biomonitoring was conducted as part of the International Polar Year Inuit Health Survey in 2007-2008. The body burden of metals (e.g. Cd, Pb) and persistent organic pollutants (e.g. PCBs, DDT & DDE, toxaphene, chlordane, PBDEs) were measured for Inuit participants (n=2172) from 36 communities in Nunavut, Nunatsiavut, and the Inuvialuit Settlement Region, in Canada. The geometric mean of blood concentrations for Cd, Pb, PCBs, DDE & DDT, toxaphene, and chlordane were higher than those in the Canadian general population. A total of 9% of study participants exceeded the intervention guideline of 100μgL(-1) for Pb, 11% of participants exceeded the trigger guideline of 5μgL(-1) for Cd, and 1% exceeded the intervention guideline of 100μgL(-1) for PCBs. Also, 3% of women of child-bearing age exceeded blood Pb of 100μgL(-1) while 28% of women of child-bearing age exceeded 5μgL(-1) of PCBs. This work showed that most Inuit Health Survey participants were below blood contaminant guidelines set by Health Canada but that metal and POP body burdens commonly exceed exposures observed in the general population of Canada.

  1. Hierarchical habitat selection by barren-ground grizzly bears in the central Canadian Arctic.

    PubMed

    McLoughlin, Philip D; Case, Ray L; Gau, Robert J; Cluff, Dean H; Mulders, Robert; Messier, François

    2002-06-01

    Using resource selection functions, we examined habitat selection patterns of barren-ground grizzly bears (Ursus arctos) in the central Canadian Arctic among and within home ranges. There was no difference between the sexes with regard to habitat selection patterns at the home range level (Wilks' λ, approx. F 11,11=1.27, P=0.37). Bear home ranges contain more esker habitat, tussock/hummock successional tundra, lichen veneer, birch seep, and tall shrub riparian areas relative to the proportional availability of habitats in the study area. We observed differences in habitat selection within home ranges among levels of sex/reproductive status (Wilks' λ, approx. F 20,412=3.32, P<0.001) and by season (Wilks' λ, approx. F 30,605=2.71, P<0.001). Eskers and tall shrub riparian zones were the habitats most preferred by bears throughout the year. Tussock/hummock successional tundra was also favored by males at varying times during the year and lichen veneers were favored in spring and autumn by most bears. Females with cubs tended to avoid the highest ranked habitat for males throughout the year. This pattern of habitat selection was not observed for females without accompanying young. Results of this study underline the importance of scale dependence in habitat selection. Failure to view habitat selection as a hierarchical process may result in a narrow and possibly misleading notion of habitat selection patterns.

  2. Cryogenic formation of brine and sedimentary mirabilite in submergent coastal lake basins, Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Grasby, Stephen E.; Rod Smith, I.; Bell, Trevor; Forbes, Donald L.

    2013-06-01

    Two informally named basins (Mirabilite Basins 1 and 2) along a submergent coastline on Banks Island, Canadian Arctic Archipelago, host up to 1 m-thick accumulations of mirabilite (Na2SO4·10H2O) underlying stratified water bodies with basal anoxic brines. Unlike isostatically uplifting coastlines that trap seawater in coastal basins, these basins formed from freshwater lakes that were transgressed by seawater. The depth of the sill that separates the basins from the sea is shallow (1.15 m), such that seasonal sea ice formation down to 1.6 m isolates the basins from open water exchange through the winter. Freezing of seawater excludes salts, generating dense brines that sink to the basin bottom. Progressive freezing increases salinity of residual brines to the point of mirabilite saturation, and as a result sedimentary deposits of mirabilite accumulate on the basin floors. Brine formation also leads to density stratification and bottom water anoxia. We propose a model whereby summer melt of the ice cover forms a temporary freshwater lens, and rather than mixing with the underlying brines, it is exchanged with seawater once the ice plug that separates the basins from the open sea melts. This permits progressive brine development and density stratification within the basins.

  3. Mapping human dimensions of climate change research in the Canadian Arctic.

    PubMed

    Ford, James D; Bolton, Kenyon; Shirley, Jamal; Pearce, Tristan; Tremblay, Martin; Westlake, Michael

    2012-12-01

    This study maps current understanding and research trends on the human dimensions of climate change (HDCC) in the eastern and central Canadian Arctic. Developing a systematic literature review methodology, 117 peer reviewed articles are identified and examined using quantitative and qualitative methods. The research highlights the rapid expansion of HDCC studies over the last decade. Early scholarship was dominated by work documenting Inuit observations of climate change, with research employing vulnerability concepts and terminology now common. Adaptation studies which seek to identify and evaluate opportunities to reduce vulnerability to climate change and take advantage of new opportunities remain in their infancy. Over the last 5 years there has been an increase social science-led research, with many studies employing key principles of community-based research. We currently have baseline understanding of climate change impacts, adaptation, and vulnerability in the region, but key gaps are evident. Future research needs to target significant geographic disparities in understanding, consider risks and opportunities posed by climate change outside of the subsistence hunting sector, complement case study research with regional analyses, and focus on identifying and characterizing sustainable and feasible adaptation interventions.

  4. Basal debris entrainment and transport in glaciers of southwestern Bylot Island, Canadian Arctic

    USGS Publications Warehouse

    Zdanowicz, C.M.; Michel, F.A.; Shilts, W.W.

    1996-01-01

    Glaciers on southwestern Bylot Island in the Canadian Arctic flow from an alpine setting in high-grade crystalline Archean terrane, on to coastal lowlands underlain by clastic sedimentary strata of Cretaceous to Tertiary age. We have used the contrasting mineralogy of the substrate as a tool to study subglacial entrainment and transport of debris in two large piedmont glaciers on Bylot Island. High chlorite/ and mica-illite/smectite ratios indicate that most basal debris is derived from crystalline rocks underlying the upper reaches of the glaciers. The subglacial accretion of Cretaceous-Tertiary sediments appears restricted to the lowermost part of the basal zone and is most noticeable near the glaciers' termini. Ice associated with discrete silty-sandy debris layers is characterized by an isotopic signature indicative of refreezing of meltwater at the glacier sole. The compositional, textural and isotopic characteristics of basal sediment and ice lead us to conclude that subglacial entrainment through basal ice accretion occurs in both the upper and marginal parts of the glaciers.

  5. Effects of shipping on marine acoustic habitats in Canadian Arctic estimated via probabilistic modeling and mapping.

    PubMed

    Aulanier, Florian; Simard, Yvan; Roy, Nathalie; Gervaise, Cédric; Bandet, Marion

    2017-08-29

    Canadian Arctic and Subarctic regions experience a rapid decrease of sea ice accompanied with increasing shipping traffic. The resulting time-space changes in shipping noise are studied for four key regions of this pristine environment, for 2013 traffic conditions and a hypothetical tenfold traffic increase. A probabilistic modeling and mapping framework, called Ramdam, which integrates the intrinsic variability and uncertainties of shipping noise and its effects on marine habitats, is developed and applied. A substantial transformation of soundscapes is observed in areas where shipping noise changes from present occasional-transient contributor to a dominant noise source. Examination of impacts on low-frequency mammals within ecologically and biologically significant areas reveals that shipping noise has the potential to trigger behavioral responses and masking in the future, although no risk of temporary or permanent hearing threshold shifts is noted. Such probabilistic modeling and mapping is strategic in marine spatial planning of this emerging noise issues. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  6. Sociocultural and behavioural determinants of obesity among Inuit in the central Canadian Arctic.

    PubMed

    Young, T K

    1996-12-01

    This paper reports on the sociocultural determinants of obesity among the Inuit people in the central Canadian Arctic, part of the Keewatin Health Assessment Study (KHAS), a comprehensive community health survey conducted during 1990/91 in eight Inuit communities in the Northwest Territories (n = 434 adults aged 18 yr +). On multivariate analysis, age is an independent predictor of obesity in both sexes. Among Inuit women, non-smoking status and a lower education is associated with various obesity indices. However, smoking is not a predictor in men, and the association with education is the reverse, i.e. the more highly educated are more likely to be obese. In addition, some obesity indices are associated with higher income, an admixed ethnic background, fluency in the Inuit language and less time spent on the land. In general Inuit men tend to show the pattern observed in developing societies, where obesity is more prevalent among those with higher SES status, whereas Inuit women are more characteristic of developed societies, where obesity is associated with a lower SES. The different sex roles in a rapidly modernizing population is most likely to be responsible for this phenomenon.

  7. Review of technology for Arctic offshore oil and gas recovery

    SciTech Connect

    Sackinger, W. M.

    1980-08-01

    The technical background briefing report is the first step in the preparation of a plan for engineering research oriented toward Arctic offshore oil and gas recovery. A five-year leasing schedule for the ice-prone waters of the Arctic offshore is presented, which also shows the projected dates of the lease sale for each area. The estimated peak production rates for these areas are given. There is considerable uncertainty for all these production estimates, since no exploratory drilling has yet taken place. A flow chart is presented which relates the special Arctic factors, such as ice and permafrost, to the normal petroleum production sequence. Some highlights from the chart and from the technical review are: (1) in many Arctic offshore locations the movement of sea ice causes major lateral forces on offshore structures, which are much greater than wave forces; (2) spray ice buildup on structures, ships and aircraft will be considerable, and must be prevented or accommodated with special designs; (3) the time available for summer exploratory drilling, and for deployment of permanent production structures, is limited by the return of the pack ice. This time may be extended by ice-breaking vessels in some cases; (4) during production, icebreaking workboats will service the offshore platforms in most areas throughout the year; (5) transportation of petroleum by icebreaking tankers from offshore tanker loading points is a highly probable situation, except in the Alaskan Beaufort; and (6) Arctic pipelines must contend with permafrost, making instrumentation necessary to detect subtle changes of the pipe before rupture occurs.

  8. A Preliminary Teleseismic Investigation of the Crust and Mantle Lithosphere Obtained from BISN in the Western Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Schaeffer, A. J.; Snyder, D. B.; Cairns, S.; Elliot, B.; Audet, P.; Esteve, C.; Murray-Bergquist, L.; Falck, H.

    2016-12-01

    The tectonic evolution of the Beaufort Sea continental margin has contributed to the maturation of these rocks into a major petroleum reservoir. Recent shallow offshore seismic reflection data suggest that Banks Island represents thin crust along a rifted margin established during the opening of the Arctic Ocean. In this case, rifting of the margin caused Banks Island to subside and accumulate sediments rich in petroleum source material. The cooling history and further subsidence of these sediments is important for understanding the thermal maturation of petroleum products. Recently published surface-wave velocity models of North America indicate seismic velocities at 100-150 km depths similar to those beneath Canada's diamond mines in the central Slave craton north of Yellowknife. These results imply that Banks Island is part of the Canadian Shield and that any kimberlites found thereon might contain diamonds. However, the fast velocities are inconsistent with this being a tectonically disrupted and thinned lithosphere along the Arctic margin of the Canada Basin. The problem is therefore to reconcile mantle structure typical of the Canadian Shield with crust typical of a rifted passive margin. Possibly related seismicity beneath the Mackenize River Delta and offshore in the Beaufort Sea has been observed for decades but its origin remains unknown, although has been suggested as due to incipient subduction of oceanic lithosphere beneath the North American craton. Resolving these questions requires high-resolution 3-D seismic models obtained from an array of broadband seismograph stations. Here we present preliminary results on the structure of the crust and uppermost mantle underlying the western Canadian Arctic. These results are generated using new data from the Banks Island Seismograph Network (BISN), three stations installed over the summer of 2014 and 2015; augmented with several USArray Transportable Array stations and older POLARIS and CNSN stations on

  9. Review of technology for Arctic offshore oil and gas recovery. Appendices

    SciTech Connect

    Sackinger, W. M.

    1980-06-06

    This volume contains appendices of the following: US Geological Survey Arctic operating orders, 1979; Det Noske Vertas', rules for the design, construction and inspection of offshore technology, 1977; Alaska Oil and Gas Association, industry research projects, March 1980; Arctic Petroleum Operator's Association, industry research projects, January 1980; selected additional Arctic offshore bibliography on sea ice, icebreakers, Arctic seafloor conditions, ice-structures, frost heave and structure icing.

  10. Reconstruction of Centennial and Millennial-scale Climate and Environmental Variability during the Holocene in the Central Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Rolland, N.; Porinchu, D.; MacDonald, G.; Moser, K.

    2007-12-01

    The Arctic and sub-Arctic regions are experiencing dramatic changes in surface temperature, sea-ice extent, glacial melt, river discharge, soil carbon storage and snow cover. According to the IPCC high latitude regions are expected to warm between 4°C and 7°C over the next 100 years. The magnitude of warming and the rate at which it occurs will dwarf any previous warming episodes experienced by latitude regions over the last 11,000 years. It is critical that we improve our understanding of how the Arctic and sub-Arctic regions responded to past periods of warming, especially in light of the changes these regions will be experiencing over the next 100 years. One of the lines of evidence increasingly utilized in multi-proxy paleolimnological research is the Chironomidae (Insecta: Diptera). Also known as non-biting midge flies, chironomids are ubiquitous, frequently the most abundant insects found in freshwater ecosystems and very sensitive to environmental conditions. This research uses Chironomidae to quantitatively characterize climate and environmental conditions of the continental interior of Arctic Canada during the Holocene. Spanning four major vegetation zones (boreal forest, forest-tundra, birch tundra and herb tundra), the surface samples of 80 lakes recovered from the central Canadian Arctic were used to assess the relationship of 22 environmental variables with the chironomid distribution. Redundancy analysis (RDA) identified four variables, total Kjeldahl nitrogen (TKN), pH, summer surface water temperature (SSWT) and depth, which best explain the variance in the distribution of chironomids within these ecoregions. In order to provide new quantitative estimates of SSWT, a 1-component weighted average partial least square (WA-PLS) model was developed (r2jack = 0.76, RMSEP = 1.42°C) and applied downcore in two low arctic continental Nunavut lakes located approximately 50 km and 200 km north of modern treeline. This robust midge-inferred temperature

  11. Spatial trends and factors affecting variation of organochlorine contaminants levels in Canadian Arctic beluga (Delphinapterus leucas).

    PubMed

    Stern, G A; Macdonald, C R; Armstrong, D; Dunn, B; Fuchs, C; Harwood, L; Muir, D C G; Rosenberg, B

    2005-12-01

    Organochlorine pesticides and PCBs were analysed in blubber from beluga (Delphinapterus leucas), or white whales, collected at 15 sites in the Canadian Arctic between 1993 and 2001. The objective of the study was to define and interpret the spatial trends of major organic contaminants in northern beluga in terms of sources and transport pathways, and the biological factors influencing accumulation. When compared on a lipid weight basis, the concentrations of beta-HCH, cis-CHL and SigmaCHL, cis-nonachlor, heptachlor epoxide and p,p'-DDT were significantly higher in males than females at all five sites in the eastern Arctic where the two sexes were harvested. The differences were attributed to losses from the females during fetal development and lactation as reported in previous studies. Major compounds increased with age in males at most sites, however the lack of a significant increase with age at some sites was in part due to high organochlorine concentrations in young year classes (2-5 years), particularly at eastern sites such as Iqaluit and Pangnirtung. Lower concentrations of SigmaHCH and SigmaDDT compounds in young males in 2001 relative to 1995 at Hendrickson Island could be due to declining levels in the environment, changes in the diet, or differences in organochlorine loads transferred from the female after birth. Age-corrected least square mean concentrations in males showed significantly higher levels of many compounds, such as p,p'-DDE and SigmaCHB, at south Baffin Island sites than those in the west. Two notable exceptions were HCBz and beta-HCH which were higher in the west. Methoxyclor was detected in males at Sanikiluaq (58 ng g-1) and in both sexes at Kimmirut, but at no other sites. Principal component analysis grouped the 16 sites into five major groupings based on the similarity of normalised organochlorine pesticide and PCB levels. Sites from the western Arctic were grouped by higher proportions of HCBz, beta-HCH and gamma-HCH and higher

  12. Spatio-temporal variations and age effect on Toxoplasma gondii seroprevalence in seals from the Canadian Arctic.

    PubMed

    Simon, A; Chambellant, M; Ward, B J; Simard, M; Proulx, J F; Levesque, B; Bigras-Poulin, M; Rousseau, A N; Ogden, N H

    2011-09-01

    Toxoplasmosis is a significant public health threat for Inuit in the Canadian Arctic. This study aimed to investigate arctic seals as a possible food-borne source of infection. Blood samples collected from 828 seals in 7 Canadian Arctic communities from 1999 to 2006 were tested for Toxoplasma gondii antibodies using a direct agglutination test. Polymerase chain reaction (PCR) was used to detect T. gondii DNA in tissues of a subsample of seals. Associations between seal age, sex, species, diet, community and year of capture, and serological test results were investigated by logistic regression. Overall seroprevalence was 10·4% (86/828). All tissues tested were negative by PCR. In ringed seals, seroprevalence was significantly higher in juveniles than in adults (odds ratio=2·44). Overall, seroprevalence varied amongst communities (P=0·0119) and by capture year (P=0·0001). Our study supports the hypothesis that consumption of raw seal meat is a significant source of infection for Inuit. This work raises many questions about the mechanism of transfer of this terrestrial parasite to the marine environment, the preponderance of infection in younger animals and the natural course of infection in seals. Further studies to address these questions are essential to fully understand the health risks for Inuit communities.

  13. History of Sea Ice Changes in the Canadian Arctic and the Impact on Humans

    NASA Astrophysics Data System (ADS)

    Mudie, P. J.; Rochon, A.; Levac, E.

    2004-05-01

    The discontinuous chronology of archaeological records from the Canadian Arctic suggests that major climatic changes caused the abrupt abandonment of settlements and life style shifts in Paleo- and Neo-Eskimo societies. The centennial-scale resolution of previous paleoclimate reconstructions, however, does not permit detailed examination of this idea. Climate warming of more than 1.5C during the past 3 decades has caused reduction of sea ice and loss of marine mammals, forcing catastrophic changes on the Inuit people. Computer models forecast continued Arctic warming up to 4C but the 150-year database for the models covers only a fraction of the warm-cold cyclicity data in Holocene geological records. We therefore examine the decadal-scale paleoclimatic changes recorded by quantitative palynological data in a 6,500 year-long record from Coburg Polynya (Core LSSL 2001-006 75 35' N, 78 41'W) near the Palaeo- and Neo-Eskimo occupations of the North Devon Lowlands and in cores Hu 91-039-008 and 007 from the central North Water Polynya (NOW) between Ellesmere Island and Thule, Greenland (77 16.0'N, 74 19.9'W). Palaeotransfer function data from dinoflagellate cyst assemblages in the cores provide quantitative estimates of changes in sea surface temperature (SST) and sea ice cover (SIC) with the same accuracy as historical shipboard oceanographic measurements. Both sites record abrupt temperature changes of 2 - 4C that can be related to the archaeological record of major changes in hunting modes of Paleo- and Neo-Eskimo peoples and to detailed occupation-abandonment cycles on Devon and Ellesmere Islands. The paleoceanographic reconstructions show that from 6500 to 2600 BP, there were large oscillations in summer SST from 2-4C cooler than now to 6C warmer, and that annual variations in SIC ranged from 2 months more of heavy (more than 50 percent) ice to a 4-month extension of open water. This interval corresponds to the period of pre-Dorset Palaeo-Eskimo cultures that

  14. Seafloor features delineate Late Wisconsinan ice stream configurations in eastern Parry Channel, Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    MacLean, B.; Blasco, S.; Bennett, R.; Lakeman, T.; Pieńkowski, A. J.; Furze, M. F. A.; Hughes Clarke, J.; Patton, E.

    2017-03-01

    Multibeam imagery and 3.5 kHz sub-bottom profiles acquired from CCGS Amundsen between 2003 and 2013 by ArcticNet and the Ocean Mapping Group at the University of New Brunswick provide information on seafloor features, geology, bathymetry and morphology in eastern Parry Channel and the adjoining large channels in the Canadian Arctic Archipelago. Together these include Peel Sound, Barrow Strait, Lancaster Sound, Wellington Channel, Prince Regent Inlet, Admiralty Inlet and Navy Board Inlet. Those data are in part complemented by high resolution single channel seismic reflection profiles acquired by the Geological Survey of Canada in the 1970s and 1980s and by sediment cores that provide chronological and depositional information. The occurrence and pattern of streamlined mega-scale ridge and groove lineations (MSGLs) indicate that these waterways were occupied by glacial ice streams in the past. Chronological information from marine and adjoining terrestrial areas suggests a long history of glacial events ranging in time from Early Pleistocene to Late Wisconsinan. Seafloor morphology and MSGL trends together with terrestrial ice flow patterns indicate that ice streams flowed into Barrow Strait from Peel Sound and Wellington Channel, and ice streams in Prince Regent, Admiralty and Navy Board inlets flowed northward into and eastward along Lancaster Sound. Recession of the ice stream westward along Parry Channel occurred ∼16 cal ka BP to 10.8 cal ka BP. Thick ice-contact sediments deposited by a late ice advance from Prince Regent Inlet constitute the seabed across a large area of western Lancaster Sound. Timing for that late ice advance appears to be bracketed between the 11.5 cal ka BP lift-off of the eastern Parry ice stream north of Prince Leopold Island and the ∼10.0 cal ka BP deglaciation of Prince Regent Inlet. Seafloor morphology and lineation trends suggest that ice delivered by the ice stream in Peel Sound was the westernmost tributary to the ice stream

  15. Cloud identification in the Canadian High Arctic using the UV-visible colour index

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoyi; Adams, Cristen; Strong, Kimberly; Duck, Thomas; Perro, Chris; Hudak, David; Rodriguez, Peter

    2014-05-01

    In UV-visible spectroscopy, Rayleigh and Mie scattering contribute to the broadband extinction seen in spectra of scattered sunlight. The relative intensity of these two components of scattering is highly dependent on the cloud condition of the sky. The colour index, defined as the ratio of light intensities at different wavelengths, typically 350 nm and 550 nm, provides a means of determining the cloud conditions. A UV-visible triple-grating spectrometer, the UT-GBS (University of Toronto Ground-Based Spectrometer), was installed at the Polar Environment Atmospheric Research Laboratory (PEARL), at Eureka in the Canadian High Arctic (86.4°W, 80.1°N) in 1999. Since then, the instrument has made daily measurements during spring from 1999-2009, and year-round, with the exception of polar night, from 2010-2013. The UT-GBS measures vertical column densities of ozone, NO2, and BrO, as well as slant column densities of enhanced OClO, by using the Differential Optical Absorption Spectroscopy (DOAS) technique. We use the colour index data from the UT-GBS to distinguish polar stratospheric clouds and tropospheric clouds. The UV-visible measurements are supplemented by vertically resolved lidar and radar cloud data products. The CANDAC (Canadian Network for the Detection of Atmospheric Change) Rayleigh-Mie-Raman Lidar (CRL) and the Millimetre Cloud Radar (MMCR) are located at the Zero Altitude PEARL Auxiliary Laboratory (0PAL), which is about 15 km away from PEARL. The CRL uses ultra-short pulses of light from two lasers, operating at ultraviolet (355 nm) and visible (532 nm) wavelengths. The CRL measures the vertical distribution of aerosols, temperature, and water vapour in the troposphere and lower stratosphere. The zenith-pointing MMCR measures equivalent radar reflectivity, Doppler velocity, spectral width, and Doppler spectra, from which information about cloud heights, thicknesses, internal structure and vertical motions can be determined. Polar stratospheric cloud

  16. Enhanced greenhouse gas emissions from the Arctic with experimental warming

    NASA Astrophysics Data System (ADS)

    Voigt, Carolina; Lamprecht, Richard E.; Marushchak, Maija E.; Lind, Saara E.; Novakovskiy, Alexander; Aurela, Mika; Martikainen, Pertti J.; Biasi, Christina

    2017-04-01

    Temperatures in the Arctic are projected to increase more rapidly than in lower latitudes. With temperature being a key factor for regulating biogeochemical processes in ecosystems, even a subtle temperature increase might promote the release of greenhouse gases (GHGs) to the atmosphere. Usually, carbon dioxide (CO2) and methane (CH4) are the GHGs dominating the climatic impact of tundra. However, bare, patterned ground features in the Arctic have recently been identified as hot spots for nitrous oxide (N2O). N2O is a potent greenhouse gas, which is almost 300 times more effective in its global warming potential than CO2; but studies on arctic N2O fluxes are rare. In this study we examined the impact of temperature increase on the seasonal GHG balance of all three important GHGs (CO2, CH4 and N2O) from three tundra surface types (vegetated peat soils, unvegetated peat soils, upland mineral soils) in the Russian Arctic (67˚ 03' N 62˚ 55' E), during the course of two growing seasons. We deployed open-top chambers (OTCs), inducing air and soil surface warming, thus mimicking predicted warming scenarios. We combined detailed CO2, CH4 and N2O flux studies with concentration measurements of these gases within the soil profile down to the active layer-permafrost interface, and complemented these GHG measurements with detailed soil nutrient (nitrate and ammonium) and dissolved organic carbon (DOC) measurements in the soil pore water profile. In our study, gentle air warming (˜1.0 ˚ C) increased the seasonal GHG release of all dominant surface types: the GHG budget of vegetated peat and mineral soils, which together cover more than 80 % of the land area in our study region, shifted from a sink to a source of -300 to 144 g CO2-eq m-2 and from -198 to 105 g CO2-eq m-2, respectively. While the positive warming response was governed by CO2, we provide here the first in situ evidence that warming increases arctic N2O emissions: Warming did not only enhance N2O emissions from

  17. Comparison of Physical Properties of Marine and Arctic Gas-Hydrate-Bearing Deposits

    NASA Astrophysics Data System (ADS)

    Winters, W. J.; Walker, M.; Collett, T. S.; Bryant, S. L.; Novosel, I.; Wilcox-Cline, R.; Bing, J.; Gomes, M. L.

    2009-12-01

    Gas hydrate (GH) occurs in both marine settings and in arctic environments within a wide variety of sediment types. Grain-size analyses from both environments indicate that intrinsic host-sediment properties have a strong influence on gas-hydrate distribution and morphologic characteristics. Depending on the amount formed or dissociated, gas hydrate can significantly change in situ sediment acoustic, mechanical, and hydraulic properties. The U.S. Geological Survey, in cooperation with the U.S. Dept. of Energy, BP Expl.-Alaska, Nat. GH Prog. of India, Canadian Geological Survey, Int. Ocean Drilling Program, Japan Oil Gas and Metals Nat. Corp., Japan Pet. Expl. Co., Int. Marine Past Global Changes Study (IMAGES) program, and Paleoceanography of the Atlantic and Geochemistry (PAGE) program, determined physical properties from marine and arctic sediments and their relation to the presence of GH. At two arctic sites, the Mount Elbert well on the Alaskan North Slope and the Mallik wells on the Mackenzie Delta, NWT, >10-m thick gas-hydrate-bearing (GHB) sandy deposits are capped by finer-grained sediments that may reduce gas migration. In the Mount Elbert well, average median grain sizes (MGS) for the two thickest GHB deposits are 65 and 60 µm. Finer-grained (average MGS of 9 and 28 µm) sediments have plug permeabilities that are 300 and 14 times smaller than underlying GHB sediment. Average MGS of GHB sediment from the Mallik 2L well is ~ 111 µm, compared to overlying sediment with an average MGS of ~ 32 µm. Gas hydrate morphology in the Gulf of Mexico (GOM) and offshore India is substantially more complex than in the arctic, and is related to pervasive, although not exclusive, finer-grained deposits. Massive, several-cm thick, GH layers were recovered in piston cores in the northern GOM, in sediment with little visible lithologic variability (average MGS ~ 0.8 µm). In wells off the east coast of India, GH was present in sand-rich, fractured clay, and reservoirs

  18. Changes in trophic position affect rates of contaminant decline at two seabird colonies in the Canadian Arctic.

    PubMed

    Braune, Birgit M; Gaston, Anthony J; Hobson, Keith A; Grant Gilchrist, H; Mallory, Mark L

    2015-05-01

    Some Arctic food web structures are being affected by climate change with potential consequences for long-term trends of environmental contaminants. We examined the effects of changes in trophic position of an Arctic-breeding seabird, the thick-billed murre (Uria lomvia), on declining rates of six major organochlorines (hexachlorobenzene, heptachlor epoxide, oxychlordane, dieldrin, p,p'-DDE and Σ69PCB) at two breeding colonies in the Canadian Arctic, one in northern Hudson Bay and one in the high Arctic. As a result of a change in diet, murres breeding in Hudson Bay lowered their trophic position during 1993-2013. After adjusting for the change in trophic position using egg δ(15)N values, the rates of decline in concentrations of all six organochlorines were reduced in the Hudson Bay murre eggs. In contrast, the murres at the high Arctic colony experienced an increase in trophic position which resulted in an increase in the rates of decline for all adjusted concentrations, except for p,p'-DDE and Σ69PCB which remained relatively unchanged. This suggests that the dramatic reduction in emissions of these compounds during the 1970s/1980s had a greater influence on the time trends than changes in diet at the high Arctic colony. Linkages between climate change and food web processes are complex, and may have serious consequences for our understanding of contaminant temporal trends. Valid trends can be deduced only when these factors have been taken into account. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  19. Organochlorine contaminant and stable isotope profiles in Arctic fox (Alopex lagopus) from the Alaskan and Canadian Arctic.

    PubMed

    Hoekstra, P F; Braune, B M; O'Hara, T M; Elkin, B; Solomon, K R; Muir, D C G

    2003-01-01

    Arctic fox (Alopex lagopus) is a circumpolar species distributed across northern Canada and Alaska. Arctic fox muscle and liver were collected at Barrow, AK, USA (n=18), Holman, NT, Canada (n=20), and Arviat, NU, Canada (n=20) to elucidate the feeding ecology of this species and relate these findings to body residue patterns of organochlorine contaminants (OCs). Stable carbon (delta 13C) and nitrogen (delta 15N) isotope analyses of Arctic fox muscle indicated that trophic position (estimated by delta 15N) is positively correlated with increasing delta 13C values, suggesting that Arctic fox with a predominantly marine-based foraging strategy occupy a higher trophic level than individuals mostly feeding from a terrestrial-based carbon source. At all sites, the rank order for OC groups in muscle was polychlorinated biphenyls (Sigma PCB) > chlordane-related compounds (Sigma CHLOR) > hexachlorocyclohexane (Sigma HCH) > total toxaphene (TOX) > or = chlorobenzenes (Sigma ClBz) > DDT-related isomers (Sigma DDT). In liver, Sigma CHLOR was the most abundant OC group, followed by Sigma PCB > TOX > Sigma HCH > Sigma ClBz > Sigma DDT. The most abundant OC analytes detected from Arctic fox muscle and liver were oxychlordane, PCB-153, and PCB-180. The comparison of delta 15N with OC concentrations indicated that relative trophic position might not accurately predict OC bioaccumulation in Arctic fox. The bioaccumulation pattern of OCs in the Arctic fox is similar to the polar bear. While Sigma PCB concentrations were highly variable, concentrations in the Arctic fox were generally below those associated with the toxicological endpoints for adverse effects on mammalian reproduction. Further research is required to properly elucidate the potential health impacts to this species from exposure to OCs.

  20. Mercury and persistent organic pollutants in native and invading forage species of the Canadian Arctic: Consequences for food web dynamics.

    PubMed

    Pedro, Sara; Fisk, Aaron T; Tomy, Gregg T; Ferguson, Steven H; Hussey, Nigel E; Kessel, Steven T; McKinney, Melissa A

    2017-10-01

    Contaminant dynamics within Arctic marine food webs may be altered through the climate-driven northward invasions of temperate/boreal species. Here, we compare tissue concentrations of total mercury (THg) and legacy and emerging persistent organic pollutants (POPs) in native versus invading forage species sampled from 2012 to 2014 near Arviat, Clyde River, and Resolute Bay, NU, representing, low, mid- and high eastern Canadian Arctic regions, respectively. Concentrations of THg, legacy Σ-polychlorinated biphenyls (ΣPCB) and Σ-organochlorine (ΣOC) pesticides were detected in all forage species, whereas emerging halogenated flame retardants were detected in only a few individuals. Concentrations of major contaminant groups among regions did not vary for Arctic cod (Boreogadus saida), while for sculpin (Cottoidea) there was no clear latitudinal trend. Thus, considering interspecific variation, native sculpin and northern shrimp (Pandalus borealis) had the highest overall concentrations of THg (0.17 ± 0.02 and 0.21 ± 0.01 μg g(-1) wet weight, respectively), ΣPCB (322 ± 35 and 245 ± 25 ng g(-1) lipid weight (lw), respectively), and ΣOC (413 ± 38 and 734 ± 64 ng g(-1) lw, respectively). Comparing the keystone native species, Arctic cod, to its 'replacement' species, capelin (Mallotus villosus) and sandlance (Ammodytes spp.), THg concentrations were higher in Arctic cod compared to capelin (p < 0.001), which was partly explained by differences in fish length. Conversely, capelin and sandlance had higher concentrations of most POPs than Arctic cod (p < 0.02). Neither feeding habitat (based on δ(13)C), trophic position (based on δ(15)N), nor fish length significantly explained these differences in POPs between Arctic cod, capelin and sandlance. Higher POPs concentrations, as well as variation in congener/compound patterns, in capelin and sandlance relative to Arctic cod seem, therefore, more likely related to a more "temperate

  1. Ingested plastic in a diving seabird, the thick-billed murre (Uria lomvia), in the eastern Canadian Arctic.

    PubMed

    Provencher, Jennifer F; Gaston, Anthony J; Mallory, Mark L; O'hara, Patrick D; Gilchrist, H Grant

    2010-09-01

    Plastic debris has become ubiquitous in the marine environment and seabirds may ingest debris which can have deleterious effects on their health. In the North Atlantic Ocean, surface feeding seabirds typically ingest high levels of plastic, while the diving auks which feed in the water column typically have much lower levels. We examined 186 thick-billed murres from five colonies in the eastern Canadian Arctic for ingested plastic debris. Approximately 11% of the birds had at least one piece of plastic debris in their gastrointestinal tracts, with debris dominated by user plastics. This is the first report of ingested plastics in an auk species in Canada's Arctic, and the highest incidence of plastic ingestion to date for thick-billed murres (Uria lomvia).

  2. Seroprevalence of parasitic zoonoses and their relationship with social factors among the Canadian Inuit in Arctic regions.

    PubMed

    Goyette, Stephanie; Cao, Zhirong; Libman, Michael; Ndao, Momar; Ward, Brian J

    2014-04-01

    Residents of Arctic communities are at increased risk of contracting infectious diseases transmitted by wildlife. Data collected from the International Polar Year Inuit Health Survey were used to determine the seroprevalence of 4 parasitic zoonoses in three Inuit jurisdictions of the Canadian Arctic and to assess risk factors of infection. To date, this is the most comprehensive survey of its kind. Immunoenzymatic methods were used for the detection of antibodies against Toxocara canis, Echinococcus granulosus, Trichinella sp., and Toxoplasma gondii. We determined the weighted prevalence of parasitic infections in 36 Inuit communities across the Inuvialuit settlement region, Nunavut, and Nunatsiavut. Our results indicate infrequent exposure to Toxocara and Echinococcus (1.7 and 6.3%, respectively). Exposure to T. gondii (27.2%) and Trichinella (18.6%) was more prevalent and was generally higher in Nunavut compared to other northern regions. Overall, seropositivity was related to age, education, and consumption of marine mammals and seafood. © 2014.

  3. Field Immune Assessment during Simulated Planetary Exploration in the Canadian Arctic

    NASA Technical Reports Server (NTRS)

    Crucian, Brian; Lee, Pascal; Stowe, Raymond; Jones, Jeff; Effenhauser, Rainer; Widen, Raymond; Sams, Clarence

    2006-01-01

    Dysregulation of the immune system has been shown to occur during space flight, although the detailed nature of the phenomenon and the clinical risks for exploration class missions has yet to be established. In addition, the growing clinical significance of immune system evaluation combined with epidemic infectious disease rates in third world countries provides a strong rationale for the development of field-compatible clinical immunology techniques and equipment. In July 2002 NASA performed a comprehensive field immunology assessment on crewmembers participating in the Haughton-Mars Project (HMP) on Devon Island in the high Canadian Arctic. The purpose of the study was to evaluate mission-associated effects on the human immune system, as well as to evaluate techniques developed for processing immune samples in remote field locations. Ten HMP-2002 participants volunteered for the study. A field protocol was developed at NASA-JSC for performing sample collection, blood staining/processing for immunophenotype analysis, wholeblood mitogenic culture for functional assessments and cell-sample preservation on-location at Devon Island. Specific assays included peripheral leukocyte distribution; constitutively activated T cells, intracellular cytokine profiles and plasma EBV viral antibody levels. Study timepoints were L-30, midmission and R+60. The protocol developed for immune sample processing in remote field locations functioned properly. Samples were processed in the field location, and stabilized for subsequent analysis at the Johnson Space Center in Houston. The data indicated that some phenotype, immune function and stress hormone changes occurred in the HMP field participants that were largely distinct from pre-mission baseline and post-mission recovery data. These immune changes appear similar to those observed in Astronauts following spaceflight. The sample processing protocol developed for this study may have applications for immune assessment during

  4. Chemical and microbial characteristics of municipal drinking water supply systems in the Canadian Arctic.

    PubMed

    Daley, Kiley; Truelstrup Hansen, Lisbeth; Jamieson, Rob C; Hayward, Jenny L; Piorkowski, Greg S; Krkosek, Wendy; Gagnon, Graham A; Castleden, Heather; MacNeil, Kristen; Poltarowicz, Joanna; Corriveau, Emmalina; Jackson, Amy; Lywood, Justine; Huang, Yannan

    2017-06-13

    Drinking water in the vast Arctic Canadian territory of Nunavut is sourced from surface water lakes or rivers and transferred to man-made or natural reservoirs. The raw water is at a minimum treated by chlorination and distributed to customers either by trucks delivering to a water storage tank inside buildings or through a piped distribution system. The objective of this study was to characterize the chemical and microbial drinking water quality from source to tap in three hamlets (Coral Harbour, Pond Inlet and Pangnirtung-each has a population of <2000) on trucked service, and in Iqaluit (population ~6700), which uses a combination of trucked and piped water conveyance. Generally, the source and drinking water was of satisfactory microbial quality, containing Escherichia coli levels of <1 MPN/100 mL with a few exceptions, and selected pathogenic bacteria and parasites were below detection limits using quantitative polymerase chain reaction (qPCR) methods. Tap water in households receiving trucked water contained less than the recommended 0.2 mg/L of free chlorine, while piped drinking water in Iqaluit complied with Health Canada guidelines for residual chlorine (i.e. >0.2 mg/L free chlorine). Some buildings in the four communities contained manganese (Mn), copper (Cu), iron (Fe) and/or lead (Pb) concentrations above Health Canada guideline values for the aesthetic (Mn, Cu and Fe) and health (Pb) objectives. Corrosion of components of the drinking water distribution system (household storage tanks, premise plumbing) could be contributing to Pb, Cu and Fe levels, as the source water in three of the four communities had low alkalinity. The results point to the need for robust disinfection, which may include secondary disinfection or point-of-use disinfection, to prevent microbial risks in drinking water tanks in buildings and ultimately at the tap.

  5. Fast carnivores and slow herbivores: differential foraging strategies among grizzly bears in the Canadian Arctic.

    PubMed

    Edwards, Mark A; Derocher, Andrew E; Hobson, Keith A; Branigan, Marsha; Nagy, John A

    2011-04-01

    Categorizing animal populations by diet can mask important intrapopulation variation, which is crucial to understanding a species' trophic niche width. To test hypotheses related to intrapopulation variation in foraging or the presence of diet specialization, we conducted stable isotope analysis (δ(13)C, δ(15)N) on hair and claw samples from 51 grizzly bears (Ursus arctos) collected from 2003 to 2006 in the Mackenzie Delta region of the Canadian Arctic. We examined within-population differences in the foraging patterns of males and females and the relationship between trophic position (derived from δ(15)N measurements) and individual movement. The range of δ(15)N values in hair and claw (2.0-11.0‰) suggested a wide niche width and cluster analyses indicated the presence of three foraging groups within the population, ranging from near-complete herbivory to near-complete carnivory. We found no linear relationship between home range size and trophic position when the data were continuous or when grouped by foraging behavior. However, the movement rate of females increased linearly with trophic position. We used multisource dual-isotope mixing models to determine the relative contributions of seven prey sources within each foraging group for both males and females. The mean bear dietary endpoint across all foraging groups for each sex fell toward the center of the mixing polygon, which suggested relatively well-mixed diets. The primary dietary difference across foraging groups was the proportional contribution of herbaceous foods, which decreased for both males and females from 42-76 to 0-27% and 62-81 to 0-44%, respectively. Grizzlies of the Mackenzie Delta live in extremely harsh conditions and identifying within-population diet specialization has improved our understanding of varying habitat requirements within the population.

  6. The impact of housing on health: an ecologic study from the Canadian Arctic.

    PubMed

    Young, T K; Mollins, C J

    1996-04-01

    An ecologic study was conducted to investigate the association between housing and health in 49 predominantly Native communities in the Northwest Territories (NWT) in the Canadian Arctic, making use of data from a housing survey and data relating to physical and social health routinely reported to various service delivery agencies. The rate of health centre visits, as a measure of morbidity, correlated with most housing and socioeconomic status (SES) indicators. Communities with worse housing and SES were found to have a higher rate of health centre visits. Using factor analysis, composite housing and SES indicators were constructed. Housing was poorly correlated with any of the outcome variables, whereas SES was strongly correlated with health centre visits and moderately correlated with the occurrence of fires. Communities with worse SES were more likely to have a higher rate of health centre visits but the opposite effect was observed with fires. When both housing and SES indices were included in a multiple regression model, SES was the stronger factor in predicting the rate of health centre visits and fires. No significant association exists between these variables and the frequency of sentenced admissions. It is possible that improvement in housing quality in the NWT may have eliminated much disparity and perhaps removed most obvious illness-generating housing features. Improved housing through subsidies, however, does not alter other components of SES such as education, employment and income. The importance of SES in health and social well-being is well known and is demonstrated in the NWT as well. This study also shows that ecologic analyses can provide relatively quick and useful data for public health policy.

  7. Reconstructing decades of glacial mass loss in the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Noël, Brice; van de Berg, Willem Jan; Lhermitte, Stef; Wouters, Bert; van den Broeke, Michiel

    2017-04-01

    The Canadian Arctic Archipelago (CAA) comprises multiple small glaciers and ice caps mostly concentrated on Ellesmere and Baffin Islands situated in the north (NCAA) and south (SCAA) of the archipelago, respectively. Because they cover a relatively small area and show complex geometries, current regional climate models, generally running at 5 to 20 km horizontal resolution, struggle to accurately resolve surface mass change patterns. Here, we present a 58-year (1958-2015) reconstruction of daily, 1 km surface mass balance (SMB) of the CAA, statistically downscaled from the output of the regional climate model RACMO2.3 at 11 km. By correcting for biases in elevation and ice albedo, the downscaling method significantly improves mass loss estimates over narrow outlet glaciers and isolated ice fields through better resolved marginal meltwater runoff. During the last two decades, CAA glaciers have experienced warmer conditions (+1.1°C) resulting in continued mass loss. NCAA and SCAA mass loss accounted for -24.7 ± 18.0 Gt yr-1 and -21.9 ± 8.2 Gt yr-1 respectively, almost tripling (-8.4 Gt yr-1) and doubling (-11.8 Gt yr-1) the 1958-1995 average. Following the recent warming, enhanced meltwater production reduced the refreezing capacity of inland firn layers by about 6%. While the interior of NCAA ice caps can still buffer most of the additional melt, the lack of a perennial firn area over low-lying SCAA glaciers caused uninterrupted mass loss since the 1980s, which, in the absence of significant refreezing capacity, indicates inevitable disappearance of these highly sensitive glaciers.

  8. Seasonal demography of a cyclic lemming population in the Canadian Arctic.

    PubMed

    Fauteux, Dominique; Gauthier, Gilles; Berteaux, Dominique

    2015-09-01

    1. The causes of cyclical fluctuations in animal populations remain a controversial topic in ecology. Food limitation and predation are two leading hypotheses to explain small mammal population dynamics in northern environments. We documented the seasonal timing of the decline phases and demographic parameters (survival and reproduction) associated with population changes in lemmings, allowing us to evaluate some predictions from these two hypotheses. 2. We studied the demography of brown lemmings (Lemmus trimucronatus), a species showing 3- to 4-year population cycles in the Canadian Arctic, by combining capture-mark-recapture analysis of summer live-trapping with monitoring of winter nests over a 10-year period. We also examined the effects of some weather variables on survival. 3. We found that population declines after a peak occurred between the summer and winter period and not during the winter. During the summer, population growth was driven by change in survival, but not in fecundity or proportion of juveniles, whereas in winter population growth was driven by changes in late summer and winter reproduction. 4. We did not find evidence for direct density dependence on summer demographic parameters, though our analysis was constrained by the paucity of data during the low phase. Body mass, however, was highest in peak years. 5. Weather effects were detected only in early summer when lemming survival was positively related to snow depth at the onset of melt but negatively related to rainfall. 6. Our results show that high mortality causes population declines of lemmings during summer and fall, which suggests that predation is sufficient to cause population crashes, whereas high winter fecundity is the primary factor leading to population irruptions. The positive association between snow depth and early summer survival may be due to the protective cover offered by snow against predators. It is still unclear why reproduction remains low during the low phase.

  9. Intercomparison of atmospheric water vapour measurements at a Canadian High Arctic site

    NASA Astrophysics Data System (ADS)

    Weaver, Dan; Strong, Kimberly; Schneider, Matthias; Rowe, Penny M.; Sioris, Chris; Walker, Kaley A.; Mariani, Zen; Uttal, Taneil; McElroy, C. Thomas; Vömel, Holger; Spassiani, Alessio; Drummond, James R.

    2017-08-01

    Water vapour is a critical component of the Earth system. Techniques to acquire and improve measurements of atmospheric water vapour and its isotopes are under active development. This work presents a detailed intercomparison of water vapour total column measurements taken between 2006 and 2014 at a Canadian High Arctic research site (Eureka, Nunavut). Instruments include radiosondes, sun photometers, a microwave radiometer, and emission and solar absorption Fourier transform infrared (FTIR) spectrometers. Close agreement is observed between all combination of datasets, with mean differences ≤ 1.0 kg m-2 and correlation coefficients ≥ 0.98. The one exception in the observed high correlation is the comparison between the microwave radiometer and a radiosonde product, which had a correlation coefficient of 0.92.A variety of biases affecting Eureka instruments are revealed and discussed. A subset of Eureka radiosonde measurements was processed by the Global Climate Observing System (GCOS) Reference Upper Air Network (GRUAN) for this study. Comparisons reveal a small dry bias in the standard radiosonde measurement water vapour total columns of approximately 4 %. A recently produced solar absorption FTIR spectrometer dataset resulting from the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) retrieval technique is shown to offer accurate measurements of water vapour total columns (e.g. average agreement within -5.2 % of GRUAN and -6.5 % of a co-located emission FTIR spectrometer). However, comparisons show a small wet bias of approximately 6 % at the high-latitude Eureka site. In addition, a new dataset derived from Atmospheric Emitted Radiance Interferometer (AERI) measurements is shown to provide accurate water vapour measurements (e.g. average agreement was within 4 % of GRUAN), which usefully enables measurements to be taken during day and night (especially valuable during polar night).

  10. Temporal trends of mercury in eggs of five sympatrically breeding seabird species in the Canadian Arctic.

    PubMed

    Braune, Birgit M; Gaston, Anthony J; Mallory, Mark L

    2016-07-01

    We compared temporal trends of total mercury (Hg) in eggs of five seabird species breeding at Prince Leopold Island in the Canadian high Arctic. As changes in trophic position over time have the potential to influence contaminant temporal trends, Hg concentrations were adjusted for trophic position (measured as δ(15)N). Adjusted Hg concentrations in eggs of thick-billed murres (Uria lomvia) and northern fulmars (Fulmarus glacialis) increased from 1975 to the 1990s, followed by a plateauing of levels from the 1990s to 2014. Trends of adjusted Hg concentrations in eggs of murres, fulmars, black guillemots (Cepphus grylle) and black-legged kittiwakes (Rissa tridactyla) had negative slopes between 1993 and 2013. Adjusted Hg concentrations in glaucous gull (Larus hyperboreus) eggs decreased by 50% from 1993 to 2003 before starting to increase again. Glaucous gull eggs had the highest Hg concentrations followed by black guillemot eggs, and black-legged kittiwake eggs had the lowest concentrations consistently in the five years compared between 1993 and 2013. Based on published toxicological thresholds for Hg in eggs, there is little concern for adverse reproductive effects due to Hg exposure in these birds, although the levels in glaucous gull eggs warrant future scrutiny given the increase in Hg concentrations observed in recent years. There is evidence that the Hg trends observed reflect changing anthropogenic Hg emissions. It remains unclear, however, to what extent exposure to Hg on the overwintering grounds influences the Hg trends observed in the seabird eggs at Prince Leopold Island. Future research should focus on determining the extent to which Hg exposure on the breeding grounds versus the overwintering areas contribute to the trends observed in the eggs.

  11. Multi-decadal frontal change rates of tidewater glaciers in the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Cook, Alison; Copland, Luke; Stokes, Chris; Bentley, Mike

    2017-04-01

    Recent studies of post-2000 observational data have shown variability in the dynamic ice discharge of tidewater glaciers throughout the Canadian Arctic Archipelago (CAA). Expanding this to all tidewater glaciers in the region on a decadal time scale using earlier records can help identify when glacier retreat began, and determine longer-term temporal trends in mass balance. Our study shows that over 94% of 300 tidewater glaciers in the CAA (from southern Baffin Island to Ellesmere Island, excluding those on the northern coast) have retreated since the earliest observational records (aerial photographs acquired in 1958-1960). Mean overall length change rate of the 211 glaciers in the Queen Elizabeth Islands (QEI) is -9.3 ma-1 (± 1.38 SE), and of the 89 glaciers on Baffin and Bylot Islands (BBI) is -7.1 ma-1 (± 0.72 SE). Mean frontal widths of tidewater glaciers in the QEI are greater than those on islands to the south, resulting in greater mean area loss from this region. Each glacier has 6 frontal positions digitised from a range of image sources at approximately decadal intervals. Length change rates have been calculated across each time interval for each glacier, based on area changes divided by glacier frontal width. Results indicate a similar temporal pattern throughout the region, whereby glaciers show minimal change in early years with retreat rates slowly increasing, followed by acceleration in retreat rates since the late 1990s. Mean change rates in the QEI and BBI in the 1960s were -6.92 ma-1 and -0.51 ma-1 respectively, increasing to -28.96 ma-1 and -24.84 ma-1 since 2010. The same trend (at differing magnitudes) has been observed within each latitudinal degree band, and for glaciers of differing frontal widths. Further observations of glacier changes and links to climate change are revealed on the poster.

  12. Acceleration of thaw slump activity in glaciated landscapes of the Western Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Segal, Rebecca A.; Lantz, Trevor C.; Kokelj, Steven V.

    2016-03-01

    Climate change is increasing the frequency and intensity of thermokarst, but the influences of regional climate and physiography remain poorly understood. Retrogressive thaw slumping is one of the most dynamic forms of thermokarst and affects many areas of glaciated terrain across northwestern Canada. In this study, we used airphotos and satellite imagery to investigate the influence of climate and landscape factors on thaw slump dynamics. We assessed slump size, density, and growth rates in four regions of ice-rich terrain with contrasting climate and physiographic conditions: the Jesse Moraine, the Tuktoyaktuk Coastlands, the Bluenose Moraine, and the Peel Plateau. Observed increases in: (1) the area impacted by slumps (+2 to +407%), (2) average slump sizes (+0.31 to +1.82 ha), and (3) slump growth rates (+169 to +465 m2 yr-1) showed that thermokarst activity is rapidly accelerating in ice-rich morainal landscapes in the western Canadian Arctic, where slumping has become a dominant driver of geomorphic change. Differences in slump characteristics among regions indicate that slump development is strongly influenced by topography, ground ice conditions, and Quaternary history. Observed increases in slump activity occurred in conjunction with increases in air temperature and precipitation, but variation in slump activity among the four regions suggests that increased precipitation has been an important driver of change. Our observation that the most rapid intensification of slump activity occurred in the coldest environment (the Jesse Moraine on Banks Island) indicates that ice-cored landscapes in cold permafrost environments are highly vulnerable to climate change.

  13. Climate change: Numerical modelling of sedimentation and coastal processes, eastern Canadian Arctic

    SciTech Connect

    Syvitski, J.P.M. ); Andrews, J.T. )

    1994-08-01

    We use three sequential [open quotes]water-sediment transport[close quotes] numerical models to evaluate changes in fluvial sediment outputs for two near-future contrasting climate-change scenarios (warmer summers or warmer and moister winters) for the eastern Canadian Arctic. Our integrated model generates values for deposition into a fiord basin. The effects of climate warming are imposed on 200-yr fluctuations in relative sea level (base level) that in turn have a long-term forcing associated with late Quaternary glacial unloading. Thus some areas are submerging (around the periphery of the former ice sheet) and others are emerging (inland at the heads of fiords). Small, short-term changes in sea level may involve meltwater supply to the world ocean from the melting of glaciers and ice sheets, and sea water expansion with a warming ocean. Alternatively, large ice sheets may also thicken over the short term (200 yr), thereby withdrawing water from the global hydrological cycle. Both climate scenarios result in an increased sediment flux over the next 200 yr. However, warmer summers will have the largest impact by (1) causing ice caps to melt, (2) inducing more expansive and turbid river plumes, (3) increasing progradation of the coastline into the sea, (4) raising relative sea level, and by (5) increasing the number and size of turbidity currents generated off river mouths. Warmer and moister winters that may lead to deviations from these impacts include (1) growth of ice caps, (2) fall of relative sea level, (3) stability of coastlines as increased sediment delivery keeps pace with changes in regional relative sea level, and (4) fewer basin turbidity currents, as more of the bedload is trapped on top of sandur surfaces. 55 refs., 11 figs., 2 tabs.

  14. Sedimentary Record of the Last two Interglacials in the Terrestrial Canadian Arctic (Pingualuit Crater Lake, Nunavik)

    NASA Astrophysics Data System (ADS)

    St-Onge, G.; Guyard, H.; Pienitz, R.; Hausmann, S.; Francus, P.; Salonen, V.; Luoto, T.; Black, J.; Lamothe, M.; Zolitschka, B.; Larocque, I.

    2009-05-01

    The Pingualuit crater lake (Nunavik, Canada) resulted from a meteoritic impact that occurred ca. 1.4 million years ago. Due to its unique morphometry (depth and shape), the lake bottom may have escaped glacial erosion. Based on a punctual seismic profile acquired using a 12 kHz Knudsen echosounder and using both gravity and piston corers, we recovered the uppermost 8.5 m of sediments. High-resolution physical (CAT- Scan, Multi Sensor Core Logger, diffuse spectral reflectance), geochemical (ITRAX core scanner, carbon and nitrogen contents, δ13C of the organic matter) and magnetic (magnetic susceptibility, natural, anhysteretic, isothermal and saturation isothermal remanent magnetizations) analyses were performed. Two main lithofacies were clearly identified by the different measurements and likely represent successive interglacial/glacial cycles. Most of the sediment consists of light grey silts containing several angular rock fragments, that is characterized by very low organic carbon content, relatively high density and magnetic susceptibility values, suggesting a deposition during glacial conditions. Interbedded between this facies are at least two decimetre-thick, organic-rich and finely laminated intervals likely representing ice free periods. The presence of diatoms, chrysophytes and chironomid head capsules in smear and microscope slides from these two intervals supports this hypothesis. In addition, preliminary Infrared Stimulated Luminescence (IRSL) measurements indicate that the upper organic-rich layer has an age coeval with the last interglacial (Oxygen Isotope Stage 5), while the age of the lower organic-rich layer is consistent with an older interglacial, likely the Oxygen Isotope Stage 7. The sedimentary infill thus constitutes a unique long-term terrestrial record of environmental and climatic conditions in the Canadian Arctic. Furthermore, because these sediments escaped glacial erosion, it suggests the presence of a subglacial lake during the last

  15. Rare earth elements in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic.

    PubMed

    MacMillan, Gwyneth Anne; Chételat, John; Heath, Joel P; Mickpegak, Raymond; Amyot, Marc

    2017-09-07

    Few ecotoxicological studies exist for rare earth elements (REEs), particularly field-based studies on their bioaccumulation and food web dynamics. REE mining has led to significant environmental impacts in several countries (China, Brazil, U.S.), yet little is known about the fate and transport of these contaminants of emerging concern. Northern ecosystems are potentially vulnerable to REE enrichment from prospective mining projects at high latitudes. To understand how REEs behave in remote northern food webs, we measured REE concentrations and carbon and nitrogen stable isotope ratios (∂(15)N, ∂(13)C) in biota from marine, freshwater, and terrestrial ecosystems of the eastern Canadian Arctic (N = 339). Wildlife harvesting and tissue sampling was partly conducted by local hunters through a community-based monitoring project. Results show that REEs generally follow a coherent bioaccumulation pattern for sample tissues, with some anomalies for redox-sensitive elements (Ce, Eu). Highest REE concentrations were found at low trophic levels, especially in vegetation and aquatic invertebrates. Terrestrial herbivores, ringed seal, and fish had low total REE levels in muscle tissue (∑REE for 15 elements <0.1 nmol g(-1)), yet accumulation was an order of magnitude higher in liver tissues. Age- and length-dependent REE accumulation also suggest that REE uptake is faster than elimination for some species. Overall, REE bioaccumulation patterns appear to be species- and tissue-specific, with limited potential for biomagnification. This study provides novel data on the behaviour of REEs in ecosystems and will be useful for environmental impact assessment of REE enrichment in northern regions.

  16. Characterization of the prokaryotic diversity in cold saline perennial springs of the Canadian high Arctic.

    PubMed

    Perreault, Nancy N; Andersen, Dale T; Pollard, Wayne H; Greer, Charles W; Whyte, Lyle G

    2007-03-01

    The springs at Gypsum Hill and Colour Peak on Axel Heiberg Island in the Canadian Arctic originate from deep salt aquifers and are among the few known examples of cold springs in thick permafrost on Earth. The springs discharge cold anoxic brines (7.5 to 15.8% salts), with a mean oxidoreduction potential of -325 mV, and contain high concentrations of sulfate and sulfide. We surveyed the microbial diversity in the sediments of seven springs by denaturing gradient gel electrophoresis (DGGE) and analyzing clone libraries of 16S rRNA genes amplified with Bacteria and Archaea-specific primers. Dendrogram analysis of the DGGE banding patterns divided the springs into two clusters based on their geographic origin. Bacterial 16S rRNA clone sequences from the Gypsum Hill library (spring GH-4) were classified into seven phyla (Actinobacteria, Bacteroidetes, Firmicutes, Gemmatimonadetes, Proteobacteria, Spirochaetes, and Verrucomicrobia); Deltaproteobacteria and Gammaproteobacteria sequences represented half of the clone library. Sequences related to Proteobacteria (82%), Firmicutes (9%), and Bacteroidetes (6%) constituted 97% of the bacterial clone library from Colour Peak (spring CP-1). Most GH-4 archaeal clone sequences (79%) were related to the Crenarchaeota while half of the CP-1 sequences were related to orders Halobacteriales and Methanosarcinales of the Euryarchaeota. Sequences related to the sulfur-oxidizing bacterium Thiomicrospira psychrophila dominated both the GH-4 (19%) and CP-1 (45%) bacterial libraries, and 56 to 76% of the bacterial sequences were from potential sulfur-metabolizing bacteria. These results suggest that the utilization and cycling of sulfur compounds may play a major role in the energy production and maintenance of microbial communities in these unique, cold environments.

  17. Persistent organic pollutant and mercury concentrations in eggs of ground-nesting marine birds in the Canadian high Arctic.

    PubMed

    Peck, Liam E; Gilchrist, H Grant; Mallory, Conor D; Braune, Birgit M; Mallory, Mark L

    2016-06-15

    We collected eggs of eight marine bird species from several colony sites in the Canadian high Arctic located at approximately 76°N and analyzed them for concentrations of legacy persistent organic pollutants (POPs) and mercury. We provide the first report on concentrations of POPs in eggs of three Arctic species (Thayer's gull Larus thayeri, Sabine's gull Xema sabini, Ross's Gull Rhodostethia rosea), and we found significant differences in each of the POP profiles among the five species with sufficient data for statistical comparisons (Thayer's gull, black guillemot Cepphus grylle, Sabine's gull, Arctic tern Sterna paradisaea and common eider Somateria mollissima borealis). The Ross's Gull had unexpectedly high POP concentrations relative to the other species examined, although this was based on a single egg, while glaucous gull Larus hyperboreus eggs from our sampling location had very low POPs. Sabine's gulls had the lowest Hg of the eggs studied, consistent with their low trophic position, but concentrations of their legacy POPs were higher than expected. We also noted that total hexachlorocyclohexanes were higher than reported elsewhere in the circumpolar Arctic in three species. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Current use pesticide and legacy organochlorine pesticide dynamics at the ocean-sea ice-atmosphere interface in resolute passage, Canadian Arctic, during winter-summer transition.

    PubMed

    Pućko, Monika; Stern, Gary A; Burt, Alexis E; Jantunen, Liisa M; Bidleman, Terry F; Macdonald, Robie W; Barber, David G; Geilfus, Nicolas-X; Rysgaard, Søren

    2017-02-15

    Here, we present the first detailed analysis of processes by which various current use pesticides (CUPs) and legacy organochlorine pesticides (OCPs) are concentrated in melt ponds that form on Arctic sea ice in the summer, when surface snow is melting and ice eventually breaks up. Four current use pesticides (dacthal, chlorpyrifos, trifluralin, and pentachloronitrobenzene) and one legacy organochlorine pesticide (α-hexachlorocyclohexane) were detected in ponds in Resolute Passage, Canadian Arctic, in 2012. Melt-pond concentrations changed over time as a function of gas exchange, precipitation, and dilution with melting sea ice. Observed increases in melt-pond concentrations for all detected pesticides were associated with precipitation events. Dacthal reached the highest concentration of all current use pesticides in ponds (95±71pgL(-1)), a value exceeding measured concentrations in the under-ice (0m) and 5m seawater by >10 and >16 times, respectively. Drainage of dacthal-enriched pond water to the ocean during ice break-up provides an important ice-mediated annual delivery route, adding ~30% of inventory in the summer Mixed Layer (ML; 10m) in the Resolute Passage, and a concentrating mechanism with potential implications for exposures to organisms such as ice algae, and phytoplankton.

  19. Oil and Gas Resources of the Arctic Alaska Petroleum Province

    USGS Publications Warehouse

    Houseknecht, David W.; Bird, Kenneth J.

    2006-01-01

    The Arctic Alaska Petroleum Province, encompassing all the lands and adjacent Continental Shelf areas north of the Brooks Range-Herald arch, is one of the most petroleum-productive areas in the United States, having produced about 15 billion bbl of oil. Seven unitized oil fields currently contribute to production, and three additional oil fields have been unitized but are not yet producing. Most known petroleum accumulations involve structural or combination structural-stratigraphic traps related to closure along the Barrow arch, a regional basement high, which has focused regional hydrocarbon migration since Early Cretaceous time. Several oil accumulations in stratigraphic traps have been developed in recent years. In addition to three small gas fields producing for local consumption, more than 20 additional oil and gas discoveries remain undeveloped. This geologically complex region includes prospective strata within passive-margin, rift, and foreland-basin sequences. Oil and gas were generated from multiple source rocks throughout the region. Although some reservoired oils appear to be derived from a single source rock, evidence for significant mixing of hydrocarbons from multiple source rocks indicates a composite petroleum system. Both extensional and contractional tectonic structures provide ample exploration targets, and recent emphasis on stratigraphic traps has demonstrated a significant resource potential in shelf and turbidite sequences of Jurassic through Tertiary age. Recent estimates of the total mean volume of undiscovered resources in the Arctic Alaska Petroleum Province by the U.S. Geological Survey and U.S. Minerals Management Service are more than 50 billion bbl of oil and natural-gas liquids and 227 trillion ft3 of gas, distributed approximately equally between Federal offshore and combined onshore and State offshore areas.

  20. Active seafloor gas vents on the Shelf and upper Slope in Canadian Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Paull, C. K.; Dallimore, S. R.; Hughes Clarke, J. E.; Blasco, S.; Taylor, A. E.; Melling, H.; Vagle, S.; Conway, K.; Riedel, M.; Lundsten, E.; Gwiazda, R.

    2012-12-01

    In the Canadian Arctic shelf and upper slope, a thermal disturbance caused by sea level rise at the end of the last glacial period, is still propagating into the subsurface and heating shelf sediments, where submerged terrestrial permafrost and gas hydrate, and marine gas hydrate are believed to occur in close proximity. On-going studies show evidence of gas venting in association with three distinct environments: Pingo-Like-Features (PLF) on the mid-shelf; along the shelf edge near the 100m contour; and ~1 km wide circular topographic features on the upper continental slope. Observations with a Remotely Operated Vehicle (ROV) show that methane is venting vigorously over point sources on the PLF's on the mid-shelf, and diffusely along the shelf edge. The stable isotopic composition of methane emanating from these environments indicates a microbial origin for the venting gas. Their negligible radiocarbon content indicates a geological source, as opposed to methangenisis associated with modern sediments. This is consistent with the change in the thermal regime produced by the last transgression. During glacial periods lower sea level exposed the current shelf to frigid sub-aerial temperatures. As a result, some areas of the shelf are underlain by >600m of ice-bonded permafrost with the base of methane hydrate stability at >1000m depths. The marine transgression imposed a change in mean annual surface temperature from -15°C or lower, to mean annual sea bottom temperatures near 0°C. The thermal disturbance is still propagating into the subsurface, stimulating the decomposition of both terrestrial permafrost and gas hydrate at depth and liberating methane. The PLF vents are believed to be sourced from the top of the gas hydrate stability field, while the gas emanating along the shelf edge can be from the decomposition of gas trapped in the permafrost or gas-hydrate underneath the continental shelf. The occurrence of water column flares over the distinctive circular

  1. Greenhouse Gas Emissions from Arctic Freshwaters: Approaches for Scaling UP

    NASA Astrophysics Data System (ADS)

    MacIntyre, S.; Cortés, A.; Cooke, M.; Sadro, S.; Kushner, P. J.

    2015-12-01

    Turbulence moderates emissions of greenhouse gases on a number of scales, and it, in turn, is moderated by processes which govern the stability of boundary layers. On the smallest scale, it mediates the fluxes of gases across the air-water interface; at intermediate scales, that is, the size of within lake eddies, it brings gases to the air-water interface; on a larger scale, eddies in the unstable atmospheric boundary layers transport gases away from water bodies and maintain concentration gradients and further, help sustain fluxes by inducing within lake turbulence. The winds and cooling which induce within-lake turbulence and over-lake boundary layers are moderated by weather patterns dependent on even larger scale physical processes. Using time series measurements of lake temperatures, surface meteorology, and profiles of temperature-gradient microstructure in Alaskan arctic lakes ranging from 0.1 to 150 ha in surface area, we quantify the dependency of turbulence in the water column and at the air-water interface on surface meteorology and lake size. We show the lake size dependent variability in the stability of atmospheric boundary layers. We illustrate the resulting lake-size and weather dependent variability in gas transfer coefficients and within lake mixing. Using cluster analysis, we identify dominant weather patterns in the Alaskan Arctic Region and link them to within lake mixing dynamics. We then illustrate the dependency of greenhouse gas emissions on variability in local weather, lake size, and weather patterns.

  2. DNA Barcoding the Canadian Arctic Flora: Core Plastid Barcodes (rbcL + matK) for 490 Vascular Plant Species

    PubMed Central

    Saarela, Jeffery M.; Sokoloff, Paul C.; Gillespie, Lynn J.; Consaul, Laurie L.; Bull, Roger D.

    2013-01-01

    Accurate identification of Arctic plant species is critical for understanding potential climate-induced changes in their diversity and distributions. To facilitate rapid identification we generated DNA barcodes for the core plastid barcode loci (rbcL and matK) for 490 vascular plant species, representing nearly half of the Canadian Arctic flora and 93% of the flora of the Canadian Arctic Archipelago. Sequence recovery was higher for rbcL than matK (93% and 81%), and rbcL was easier to recover than matK from herbarium specimens (92% and 77%). Distance-based and sequence-similarity analyses of combined rbcL + matK data discriminate 97% of genera, 56% of species, and 7% of infraspecific taxa. There is a significant negative correlation between the number of species sampled per genus and the percent species resolution per genus. We characterize barcode variation in detail in the ten largest genera sampled (Carex, Draba, Festuca, Pedicularis, Poa, Potentilla, Puccinellia, Ranunculus, Salix, and Saxifraga) in the context of their phylogenetic relationships and taxonomy. Discrimination with the core barcode loci in these genera ranges from 0% in Salix to 85% in Carex. Haplotype variation in multiple genera does not correspond to species boundaries, including Taraxacum, in which the distribution of plastid haplotypes among Arctic species is consistent with plastid variation documented in non-Arctic species. Introgression of Poa glauca plastid DNA into multiple individuals of P. hartzii is problematic for identification of these species with DNA barcodes. Of three supplementary barcode loci (psbA–trnH, psbK–psbI, atpF–atpH) collected for a subset of Poa and Puccinellia species, only atpF–atpH improved discrimination in Puccinellia, compared with rbcL and matK. Variation in matK in Vaccinium uliginosum and rbcL in Saxifraga oppositifolia corresponds to variation in other loci used to characterize the phylogeographic histories of these Arctic-alpine species. PMID

  3. Environmental controls on the 2H/1H values of terrestrial leaf waxes in the eastern Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Shanahan, Timothy M.; Hughen, Konrad A.; Ampel, Linda; Sauer, Peter E.; Fornace, Kyrstin

    2013-10-01

    The hydrogen isotope composition of plant waxes preserved in lacustrine sediments is a potentially valuable tool for reconstructing paleoenvironmental changes in the Arctic. However, in contrast to the mid- and low-latitudes, significantly less effort has been directed towards understanding the factors controlling D/H fractionation in high latitude plant waxes and the impact of these processes on the interpretation of sedimentary leaf wax δD records. To better understand these processes, we examined the D/H ratios of long chain fatty acids in lake surface sediments spanning a temperature and precipitation gradient on Baffin Island in the eastern Canadian Arctic. D/H ratios of plant waxes increase with increasing temperature and aridity, with values ranging from -240‰ to -160‰ over the study area. Apparent fractionation factors between n-alkanoic acids in Arctic lake sediments and precipitation(εFA-ppt) are less negative than those of mid-latitude lakes and modern plants by 25‰ to 65‰, consistent with n-alkane data from modern Arctic plants (Yang et al., 2011). Furthermore, εFA-ppt values from Arctic lakes become systematically more positive with increasing evaporation, in contrast to mid-latitude sites, which show little to no change in fractionation with aridity. These data are consistent with enhanced water loss and isotope fractionation at higher latitude in the Arctic summer, when continuous sunlight supports increased daily photosynthesis. The dominant control on δDFA variations on Baffin Island is temperature. However, changing εFA-ppt result in steeper δDFA-temperature relationships than observed for modern precipitation. The application of this δDFA-based paleotemperature calibration to existing δDFA records from Baffin Island produces much more realistic changes in late Holocene temperature and highlights the importance of these effects in influencing the interpretation of Arctic δDFA records. A better understanding of the controls on

  4. Heavy metal bioaccumulation and histopathological alterations in wild Arctic hares (Lepus arcticus) inhabiting a former lead-zinc mine in the Canadian high Arctic: A preliminary study.

    PubMed

    Amuno, S; Niyogi, S; Amuno, M; Attitaq, J

    2016-06-15

    A preliminary study was undertaken to determine post-mining baseline accumulation of selected trace metals, and histopathological alterations in free-living arctic hares (Lepus arcticus) inhabiting the vicinity of a former lead-zinc mine located on North Baffin Island in the Canadian High Arctic. Trace metal analysis included measurement of As, Cd, Fe, Pb and Zn in tissues, and histopathological assessment comprised of evaluation and scoring the severity of metal-induced hepatic and renal lesions. Metal contents in hepatic and renal tissues from hares from the mine area compared with the reference locations did not differ significantly suggesting that the animals are not uniformly exposed to background levels of metals in the environment. However, relatively higher accumulation pattern of Pb and Cd were noted in liver tissues of hare from the mine area compared to the background area, but did not induce increased lesions. Surface soils near the mine area contained relatively higher levels of trace metals (Zn>Mn>Pb>Cd>As) compared to reference soils, and with soil levels of Cd showing strong correlation with Cd accumulation in kidney tissues. Generally, both case and reference animals showed similar but varying severities of hepatic and renal lesions at the sublethal level, notably vascular congestion, occasional large hepatocyte nuclei, binucleate hepatocytes, yellow-brown pigmentation in the cytoplasm of hepatocytes and clustering of lymphocytes. Only hares with relatively higher accumulation of Pb from the mine area showed evidence of renal edema and hemorrhage of the capsular surface. This study constitutes the first assessment of metal induced histopathological alterations in arctic hares exposed to a historical mining area in the high arctic.

  5. Determining Sea-Level Rise and Coastal Subsidence in the Canadian Arctic Using a Dense GPS Velocity Field for North America

    NASA Astrophysics Data System (ADS)

    Craymer, M.; Forbes, D.; Henton, J.; Lapelle, E.; Piraszewski, M.; Solomon, S.

    2005-12-01

    established co-located tide gauges and continuous GPS at a number of sites across the Canadian Arctic, including Tuktoyaktuk on the eastern side of the Mackenzie Delta. We are also investigating additional sources of subsidence in the delta, including sediment loading, compaction of unfrozen and discontinuously ice-bonded sediments, and anticipated subsidence resulting from future natural gas production. Further densification of the velocity field, including the addition of new sites in the delta, and regular reoccupation of episodic sites will assist in determining local rates of motion. Strategies for discriminating the various components of subsidence in this large delta include episodic GPS on monuments and borehole casing penetrating to various depths and supporting InSAR analysis and geological data. Coastal flooding hazards will be evaluated using digital elevation models derived from real-time kinematic GPS, airborne LiDAR surveys, and synthetic aperture radar flood mapping.

  6. The Empirical Canadian High Arctic Ionospheric Model (E-CHAIM): NmF2 and hmF2 specification

    NASA Astrophysics Data System (ADS)

    Themens, David; Jayachandran, Thayyil

    2016-07-01

    It is well known that the IRI suffers reduced accuracy in its representation of monthly median ionospheric variability at high latitudes (Themens et al. 2014, Themens et al. 2016). These inaccuracies are believed to stem from a historical lack of data from these regions. Now, roughly thirty and forty years after the development of the original URSI and CCIR foF2 maps, respectively, there exists a much larger dataset of high latitude observations of ionospheric electron density. These new measurements come in the form of new ionosonde deployments, such as those of the Canadian High Arctic Ionospheric Network, the CHAMP, GRACE, and COSMIC radio occultation missions, and the construction of the Poker Flat, Resolute, and EISCAT Incoherent Scatter Radars systems. These new datasets afford an opportunity to revise the IRI's representation of the high latitude ionosphere. For this purpose, we here introduce the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM), which will incorporate all of the above datasets, as well as the older observation records, into a new climatological representation of the high latitude ionosphere. In this presentation, we introduce the NmF2 and hmF2 portions of the model and present a validation of the new model with respect to ionosonde observations in Alert, Canada. A comparison with respect to IRI performance will also be presented.

  7. Socioeconomic and Cultural Correlates of Diet Quality in the Canadian Arctic: Results from the 2007-2008 Inuit Health Survey.

    PubMed

    Galloway, Tracey; Johnson-Down, Louise; Egeland, Grace M

    2015-09-01

    We examined the impact of socioeconomic and cultural factors on dietary quality in adult Inuit living in the Canadian Arctic. Interviews and a 24-h dietary recall were administered to 805 men and 1292 women from Inuit regions in the Canadian Arctic. We examined the effect of age, sex, education, income, employment, and cultural variables on respondents' energy, macronutrient intake, sodium/potassium ratio, and healthy eating index. Logistic regression was used to assess the impact of socioeconomic status (SES) on diet quality indicators. Age was positively associated with traditional food (TF) consumption and greater energy from protein but negatively associated with total energy and fibre intake. Associations between SES and diet quality differed considerably between men and women and there was considerable regional variability in diet quality measures. Age and cultural variables were significant predictors of diet quality in logistic regression. Increased age and use of the Inuit language in the home were the most significant predictors of TF consumption. Our findings are consistent with studies reporting a nutrition transition in circumpolar Inuit. We found considerable variability in diet quality and complex interaction between SES and cultural variables producing mixed effects that differ by age and gender.

  8. Declining trends of polychlorinated dibenzo-p-dioxins, dibenzofurans and non-ortho PCBs in Canadian Arctic seabirds.

    PubMed

    Braune, Birgit M; Mallory, Mark L

    2017-01-01

    Polychorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCBs) such as the non-ortho PCBs (nPCBs) persist in the environment despite international measures to ban their emissions. We determined congener patterns and temporal trends for PCDDs, PCDFs, nPCBs as well as their toxic equivalents (TEQs) in eggs of thick-billed murres (Uria lomvia) and northern fulmars (Fulmarus glacialis) sampled from Prince Leopold Island in the Canadian Arctic between 1975 and 2014. The dominant PCDD congeners were 1,2,3,7,8-PnCDD, 2,3,7,8-TCDD and 1,2,3,6,7,8-HxCDD, and the dominant PCDF congener was 2,3,4,7,8-PnCDF. The nPCB profile was dominated by PCB-126. The TEQ profile in the murre eggs was dominated by nPCB-TEQ whereas in the fulmar eggs, the PCDF-TEQ contribution to ΣTEQ was slightly greater than that of nPCB-TEQ. Concentrations of ΣPCDD, ΣPCDF, ΣnPCB and ΣTEQ declined between 1975 and 2014 in both murre and fulmar eggs. Based on TEQ thresholds in the literature for other species, and taking into account the trend towards declining TEQ levels, it is unlikely that current levels of PCDDs, PCDFs or nPCBs are affecting the reproductive success of thick-billed murres or northern fulmars in the Canadian Arctic.

  9. The geomorphology of two hyper-saline springs in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Ward, Melissa; Pollard, Wayne

    2015-04-01

    On Axel Heiberg Island in the Canadian High Arctic, many low temperature perennial saline springs occur despite cold polar desert climate conditions marked by a mean annual air temperature of -18°C. Associated with 2 groups of hyper-saline springs are distinctive landforms resulting from winter deposition of salt minerals. These deposits resemble tufas structurally, but unlike true tufas which are composed of carbonate minerals, these landforms are formed mainly of salt. This study hypothesizes that the extreme cold winter air temperatures cool water temperatures triggering rapid precipitation of various salt minerals [mainly hydrohalite (NaCl*2H2O)]. These newly formed salt minerals subsequently alter the flow hydrology by obstructing summer flow paths. The tufa-like appearance of these salt deposits reflects the interaction between changing water temperature, chemistry and flow.This research characterises the geomorphology and geochemistry of two hyper-saline springs on Axel Heiberg Island: the first is located at Wolf Diapir (79°07'23"N; 90°14'39"W), the deposit at this site resembles a large conical mound (2.5m tall x 3m diameter). The second is located at Stolz Diapir (79°04'30"N; 87°04'30"W). In this case a series of pool and barrage structures staircase down a narrow valley for approximately 300m (several pools are up to 10 m wide x 3 m deep). The springs have very different seasonal surface hydrologic regimes and topographic settings which influence the pattern of mineral precipitates. The accumulation of precipitates occurs during the winter and is dominated by the formation of hydrohalite. In the summer, the accumulated hydrohalite melts incongruently to form halite. In addition, spring water and snowmelt dissolve various parts of the accumulations, changing the morphology of the deposits. This presentation will focus on results from four periods of fieldwork (two in spring for winter conditions and two in summer) including results from time

  10. Assessing determinants of maternal blood concentrations for persistent organic pollutants and metals in the eastern and western Canadian Arctic.

    PubMed

    Curren, Meredith S; Liang, Chun Lei; Davis, Karelyn; Kandola, Kami; Brewster, Janet; Potyrala, Mary; Chan, Hing Man

    2015-09-15

    Aboriginal peoples in the Canadian Arctic are exposed to persistent organic pollutants (POPs) and metals mainly through their consumption of a traditional diet of wildlife items. Recent studies indicate that many human chemical levels have decreased in the north, likely due to a combination of reduced global chemical emissions, dietary shifts, and risk mitigation efforts by local health authorities. Body burdens for chemicals in mothers can be further offset by breastfeeding, parity, and other maternal characteristics. We have assessed the impact of several dietary and maternal covariates following a decade of awareness of the contaminant issue in northern Canada, by performing multiple stepwise linear regression analyses from blood concentrations and demographic variables for 176 mothers recruited from Nunavut and the Northwest Territories during the period 2005-2007. A significant aboriginal group effect was observed for the modeled chemicals, except for lead and cadmium, after adjusting for covariates. Further, blood concentrations for POPs and metals were significantly associated with at least one covariate of older age, fewer months spent breastfeeding, more frequent eating of traditional foods, or smoking during pregnancy. Cadmium had the highest explained variance (72.5%) from just two significant covariates (current smoking status and parity). Although Inuit participants from the Northwest Territories consumed more traditional foods in general, Inuit participants from coastal communities in Nunavut continued to demonstrate higher adjusted blood concentrations for POPs and metals examined here. While this is due in part to a higher prevalence of marine mammals in the eastern Arctic diet, it is possible that other aboriginal group effects unrelated to diet may also contribute to elevated chemical body burdens in Canadian Arctic populations.

  11. Evidence of weak contaminant-related oxidative stress in glaucous gulls (Larus hyperboreus) from the Canadian Arctic.

    PubMed

    Wayland, Mark; Hoffman, David J; Mallory, Mark L; Alisauskas, Ray T; Stebbins, Katherine R

    2010-01-01

    Environmental contaminants are transported over great distances to Arctic ecosystems, where they can accumulate in wildlife. Whether contaminant concentrations in wildlife are sufficient to produce adverse effects remains poorly understood. Exposure to contaminants elevates oxidative stress with possible fitness consequences. The glaucous gull (Larus hyperboreus), an Arctic top predator, was used as a bioindicator for investigating relationships between contaminant levels (organochlorines and polychlorinated biphenyls [OC/PCB], mercury [Hg], and selenium [Se]) and measures of oxidative stress (glutathione [GSH] metabolism and lipid peroxidation) in Canadian Arctic ecosystems. Contaminant levels were low and associations between contaminant exposure and oxidative stress were weak. Nevertheless, glutathione peroxidase activity rose with increasing hepatic Se concentrations, levels of thiols declined as Hg and OC/PCB levels rose, and at one of the two study sites levels of lipid peroxidation were elevated with increasing levels of hepatic Hg. These results suggest the possibility of a deleterious effect of exposure to contaminants on gull physiology even at low contaminant exposures.

  12. Household Crowding and Food Insecurity Among Inuit Families With School-Aged Children in the Canadian Arctic

    PubMed Central

    Muckle, Gina; Dewailly, Éric; Jacobson, Joseph L.; Jacobson, Sandra W.; Ayotte, Pierre; Riva, Mylène

    2015-01-01

    Objectives. We examined the relation of household crowding to food insecurity among Inuit families with school-aged children in Arctic Quebec. Methods. We analyzed data collected between October 2005 and February 2010 from 292 primary caregiver–child dyads from 14 Inuit communities. We collected information about household conditions, food security, and family socioeconomic characteristics by interviews. We used logistic regression models to examine the association between household crowding and food insecurity. Results. Nearly 62% of Inuit families in the Canadian Arctic resided in more crowded households, placing them at risk for food insecurity. About 27% of the families reported reducing the size of their children’s meals because of lack of money. The likelihood of reducing the size of children’s meals was greater in crowded households (odds ratio = 3.73; 95% confidence interval = 1.96, 7.12). After we adjusted for different socioeconomic characteristics, results remained statistically significant. Conclusions. Interventions operating across different levels (community, regional, national) are needed to ensure food security in the region. Targeting families living in crowded conditions as part of social and public health policies aiming to reduce food insecurity in the Arctic could be beneficial. PMID:25602890

  13. A Community-Based, Environmental Chronic Disease Prevention Intervention to Improve Healthy Eating Psychosocial Factors and Behaviors in Indigenous Populations in the Canadian Arctic

    ERIC Educational Resources Information Center

    Mead, Erin L.; Gittelsohn, Joel; Roache, Cindy; Corriveau, André; Sharma, Sangita

    2013-01-01

    Diet-related chronic diseases are highly prevalent among indigenous populations in the Canadian Arctic. A community-based, multi-institutional nutritional and lifestyle intervention--Healthy Foods North--was implemented to improve food-related psychosocial factors and behaviors among Inuit and Inuvialuit in four intervention communities (with two…

  14. A Community-Based, Environmental Chronic Disease Prevention Intervention to Improve Healthy Eating Psychosocial Factors and Behaviors in Indigenous Populations in the Canadian Arctic

    ERIC Educational Resources Information Center

    Mead, Erin L.; Gittelsohn, Joel; Roache, Cindy; Corriveau, André; Sharma, Sangita

    2013-01-01

    Diet-related chronic diseases are highly prevalent among indigenous populations in the Canadian Arctic. A community-based, multi-institutional nutritional and lifestyle intervention--Healthy Foods North--was implemented to improve food-related psychosocial factors and behaviors among Inuit and Inuvialuit in four intervention communities (with two…

  15. 77 FR 2513 - Draft Environmental Impact Statement for Effects of Oil and Gas Activities in the Arctic Ocean

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-18

    ... Effects of Oil and Gas Activities in the Arctic Ocean AGENCY: National Marine Fisheries Service (NMFS... the Effects of Oil and Gas Activities in the Arctic Ocean.'' Based on several written requests.../pr/permits/eis/arctic.htm . FOR FURTHER INFORMATION CONTACT: Candace Nachman, Jolie Harrison, or...

  16. Hydrological modelling of Toxoplasma gondii oocysts transport to investigate contaminated snowmelt runoff as a potential source of infection for marine mammals in the Canadian Arctic.

    PubMed

    Simon, Audrey; Rousseau, Alain N; Savary, Stéphane; Bigras-Poulin, Michel; Ogden, Nicholas H

    2013-09-30

    Toxoplasma gondii (T. gondii) is a zoonotic protozoan that sometimes causes serious illness in humans and other animals worldwide, including the Canadian Arctic. Wild and domestic felids, the only hosts able to shed T. gondii oocysts, are practically non-existent in the Canadian Arctic. So here the hypothesis that T. gondii oocysts, shed in the southern areas of the boreal watershed, could contaminate the Arctic coastal marine environment via surface runoff, particularly during the spring snowmelt period, was explored. A watershed model was applied to simulate the hydrological transport of T. gondii oocysts during the snowmelt period and test the possible efficiency of river-to-sea transport as a potential source of marine organisms' exposure to this pathogen. Simulations were run for two pilot watersheds with the ultimate aim of extrapolating the results across the Canadian Arctic watersheds. Results suggest that daily stream flow concentrations of T. gondii oocysts at the river outlet are likely to be very low. However, accumulation of oocysts in the estuarine areas may be large enough to contaminate estuarine/marine filter-feeding molluscs and snails on which seals and other marine mammals may feed. Potential maximum concentrations of T. gondii oocysts in runoff are reached at the beginning of the snowmelt period with maxima varying with discharge rates into rivers and how far upstream oocysts are discharged. Meteorological conditions during the snowmelt period can affect simulated concentrations of oocysts. These findings support the hypothesis that T. gondii oocysts carried in snowmelt runoff could be a source of T. gondii infection for marine mammals in the Canadian Arctic, and for Arctic human populations that hunt and consume raw meat from marine mammals.

  17. Temporal and spatial variabilities of atmospheric polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and polycyclic aromatic hydrocarbons (PAHs) in the Canadian Arctic: results from a decade of monitoring.

    PubMed

    Hung, H; Blanchard, P; Halsall, C J; Bidleman, T F; Stern, G A; Fellin, P; Muir, D C G; Barrie, L A; Jantunen, L M; Helm, P A; Ma, J; Konoplev, A

    2005-04-15

    The Northern Contaminants Program (NCP) baseline monitoring project was established in 1992 to monitor for persistent organic pollutants (POPs) in Arctic air. Under this project, weekly samples of air were collected at four Canadian and two Russian arctic sites, namely Alert, Nunavut; Tagish, Yukon; Little Fox Lake, Yukon; Kinngait, Nunavut; Dunai Island, Russia and Amderma, Russia. Selected POPs, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides, were analyzed in both the gas and particulate phases. This paper summarizes results obtained from this project in the past 5 years. Temporal trends were developed for atmospheric PCBs and OCs observed at Alert using a digital filtration (DF) technique. It was found that trends developed with 5 years of data (1993-1997) did not differ significantly from those determined with 7 years of data (1993-1999). This implies that with the DF technique, long-term trends can still be developed with less than 10 years of data. An acceleration in decline of OC and PCB air concentrations was noted in 1999 for some compounds, although the reason is unknown. Monitoring efforts must continue to assess the effect of this decline on the long-term trends of POPs in the Canadian Arctic. Occasional high trans-/cis-chlordane ratios and heptachlor air concentrations measured at Alert between 1995 and 1997 suggests sporadic fresh usage of chlordane-based pesticides. However, significant decreasing trends of chlordanes along with their chemical signatures has provided evidence that emission of old soil residues is replacing new usage as an important source to the atmosphere. Measurements of OC air concentrations conducted at Kinngait in 1994-1995 and 2000-2001 indicated faster OC removal at this location than at Alert. This may be attributed to the proximity of Kinngait to temperate regions where both biotic and abiotic degradation rates are faster. The PAH concentrations observed

  18. Impacts of Human Activity on the Microbial Communities of Devon Island, Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Bywaters, K. B.; Burton, A. S.; Wallace, S. L.; Glass, B. J.

    2016-09-01

    The impacts of human activities on microbial communities in arctic environments are poorly understood. This project compares the distribution of microbes at the HMP Mars analog site prior to and after human settlement.

  19. Quantitative Reconstruction of Holocene Climates of Canadian Arctic and Greenland from pollen assemblages

    NASA Astrophysics Data System (ADS)

    Whitmore, J.; Gajewski, K.

    2004-05-01

    Ice cores have provided key records of the late-Quaternary climates of the North American Arctic. However, these are spatially restricted and are available only in the glaciated eastern Arctic and Greenland. Ten pollen diagrams are available from Banks, Prince of Wales, Somerset, Ellesmere and Baffin Island describe the changes in the postglacial vegetation. These pollen assemblages, along with other proxy-climate data, have been interpreted as indicating a relatively warm early Holocene with a cooling in the past several 1000 years. However, quantitative reconstructions of the magnitude of temperature change have been hampered by lack of a sufficiently extensive modern calibration dataset. A new modern pollen dataset has recently been prepared, permitting the quantitative reconstructions of summer conditions across the Arctic. We use the modern pollen dataset, along with high-resolution estimates of July temperatures to estimate the magnitude of the Holocene climate changes across the Arctic and compare these results to the ice core records.

  20. Spatial, temporal, and source variations of hydrocarbons in marine sediments from Baffin Bay, Eastern Canadian Arctic.

    PubMed

    Foster, Karen L; Stern, Gary A; Carrie, Jesse; Bailey, Joscelyn N-L; Outridge, Peter M; Sanei, Hamed; Macdonald, Robie W

    2015-02-15

    With declining sea ice conditions in Arctic regions owing to changing climate, the large prospective reservoirs of oil and gas in Baffin Bay and Davis Strait are increasingly accessible, and the interest in offshore exploration and shipping through these regions has increased. Both of these activities are associated with the risk of hydrocarbon releases into the marine ecosystem. However, hydrocarbons are also present naturally in marine environments, in some cases deriving from oil seeps. We have analyzed hydrocarbon concentrations in eleven sediment cores collected from northern Baffin Bay during 2008 and 2009 Amundsen expeditions and have examined the hydrocarbon compositions in both pre- and post-industrial periods (i.e., before and after 1900) to assess the sources of hydrocarbons, and their temporal and spatial variabilities. Concentrations of ΣPAHs ranged from 341 to 2693 ng g(-1) dw, with concentrations in cores from sites within the North Water (NOW) Polynya generally higher. Individual PAH concentrations did not exceed concentrations of concern for marine aquatic life, with one exception found in a core collected within the NOW (one of the seven sediment core samples). Hydrocarbon biomarkers, including alkane profiles, OEP (odd-to-even preference), and TAR (terrigenous/aquatic ratios) values indicated that organic carbon at all sites is derived from both terrigenous higher plants and marine algae, the former being of greater significance at coastal sites, and the latter at the deepest sites at the southern boundary of the NOW. Biomarker ratios and chemical profiles indicate that petrogenic sources dominate over combustion sources, and thus long-range atmospheric transport is less significant than inputs from weathering. Present-day and historic pre-1900 hydrocarbon concentrations exhibited less than an order of magnitude difference for most compounds at all sites. The dataset presented here provides a baseline record of hydrocarbon concentrations in

  1. Microbial characterization of a subzero, hypersaline methane seep in the Canadian High Arctic.

    PubMed

    Niederberger, Thomas D; Perreault, Nancy N; Tille, Stephanie; Lollar, Barbara Sherwood; Lacrampe-Couloume, Georges; Andersen, Dale; Greer, Charles W; Pollard, Wayne; Whyte, Lyle G

    2010-10-01

    We report the first microbiological characterization of a terrestrial methane seep in a cryo-environment in the form of an Arctic hypersaline (∼24% salinity), subzero (-5 °C), perennial spring, arising through thick permafrost in an area with an average annual air temperature of -15 °C. Bacterial and archaeal 16S rRNA gene clone libraries indicated a relatively low diversity of phylotypes within the spring sediment (Shannon index values of 1.65 and 1.39, respectively). Bacterial phylotypes were related to microorganisms such as Loktanella, Gillisia, Halomonas and Marinobacter spp. previously recovered from cold, saline habitats. A proportion of the bacterial phylotypes were cultured, including Marinobacter and Halomonas, with all isolates capable of growth at the in situ temperature (-5 °C). Archaeal phylotypes were related to signatures from hypersaline deep-sea methane-seep sediments and were dominated by the anaerobic methane group 1a (ANME-1a) clade of anaerobic methane oxidizing archaea. CARD-FISH analyses indicated that cells within the spring sediment consisted of ∼84.0% bacterial and 3.8% archaeal cells with ANME-1 cells accounting for most of the archaeal cells. The major gas discharging from the spring was methane (∼50%) with the low CH(4)/C(2+) ratio and hydrogen and carbon isotope signatures consistent with a thermogenic origin of the methane. Overall, this hypersaline, subzero environment supports a viable microbial community capable of activity at in situ temperature and where methane may behave as an energy and carbon source for sustaining anaerobic oxidation of methane-based microbial metabolism. This site also provides a model of how a methane seep can form in a cryo-environment as well as a mechanism for the hypothesized Martian methane plumes.

  2. The geomorphology of two hyper-saline springs in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Ward, M. K.; Pollard, W. H.

    2013-12-01

    On Axel Heiberg Island in the Canadian High Arctic a number of low temperature perennial saline springs occur despite being subject to a cold polar desert climate with a mean annual air temperature of -18°C. Associated with 2 groups of hyper-saline springs are distinctive landforms resulting from winter deposition of salt minerals. These deposits resemble tufas structurally but unlike true tufas which are composed of carbonate minerals, these landforms are formed mainly of salt. This study hypothesizes that the extreme cold winter air temperatures cools water temperatures triggering rapid precipitation of various salt minerals (mainly hydrohalite, NaCl*2H2O) which subsequently alters the flow hydrology by obstructing summer flow paths. The tufa-like appearance of these salt deposits reflects the interaction between changing water temperature, chemistry and flow. This research characterises the geomorphology and geochemistry of two hyper-saline springs on Axel Heiberg Island: the first is located at Wolf Diapir (79°07'23'N; 90°14'39'W), the deposit at this site resembles a large conical mound (2.5m tall x 3m diameter). The second is located at Stolz Diapir (79°04'30'N; 87°04'30'W), in this case a series of pool and barrage structures staircase down a narrow valley for approximately 300m (several pools are 10 m wide x 3 m deep). The springs have very different seasonal surface hydrologic regimes and topographic settings which influence the pattern of mineral precipitates. The accumulation of precipitates occurs during the winter and is dominated by the formation of hydrohalite. In the summer, the accumulated hydrohalite melts incongruently to form halite; spring water and snowmelt dissolves various parts of the accumulations, changing the morphology of the deposits. The aim of this poster is to present preliminary observations characterising the processes driving tufa formation in a permafrost environment, a process that has not been described in detail in

  3. Regional Climate Modeling over the Glaciated Regions of the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Gready, Benjamin P.

    The Canadian Arctic Islands (CAI) contain the largest concentration of terrestrial ice outside of the continental ice sheets. Mass loss from this region has recently increased sharply due to above average summer temperatures. Thus, increasing the understanding of the mechanisms responsible for mass loss from this region is critical. Previously, Regional Climate Models (RCMs) have been utilized to estimate climatic balance over Greenland and Antarctica. This method offers the opportunity to study a full suite of climatic variables over extensive spatially distributed grids. However, there are doubts of the applicability of such models to the CAI, given the relatively complex topography of the CAI. To test RCMs in the CAI, the polar version of the regional climate model MM5 was run at high resolution over Devon Ice Cap. At low altitudes, residuals (computed through comparisons with in situ measurements) in the net radiation budget were driven primarily by residuals in net shortwave (NSW) radiation. Residuals in NSW are largely due to inaccuracies in modeled cloud cover and modeled albedo. Albedo on glaciers and ice sheets is oversimplified in Polar MM5 and its successor, the Polar version of the Weather Research and Forecast model (Polar WRF), and is an obvious place for model improvement. Subsequently, an inline parameterization of albedo for Polar WRF was developed as a function of the depth, temperature and age of snow. The parameterization was able to reproduce elevation gradients of seasonal mean albedo derived from satellite albedo measurements (MODIS MOD10A1 daily albedo), on the western slope of the Greenland Ice Sheet for three years. Feedbacks between modelled albedo and modelled surface energy budget components were identified. The shortwave radiation flux feeds back positively with changes to albedo, whereas the longwave, turbulent and ground energy fluxes all feed back negatively, with a maximum combined magnitude of two thirds of the shortwave feedback

  4. Changes in snowfall and snow on the ground in the Western Canadian Arctic and implications to streamflow

    NASA Astrophysics Data System (ADS)

    Marsh, P.; Lesack, L.; Shi, X.; Yang, D.

    2014-12-01

    The climate of the Western Canadian Arctic has undergone dramatic warming of air temperature over the last 50 years. In addition, there have been apparent decreases in both snow depth on the ground at the end of winter and winter precipitation. However, there have been significant changes in methods used, including changes in snow on the ground observations, and snowfall measurements. This presentation will analyze the various existing data sets at the Environment Canada weather stations at Inuvik and Tuktoyaktuk, Northwest Territories, and at nearby long term research stations of Trail Valley and Havikpak Creeks to better consider changes in snowfall and snow on the ground. This paper will then consider the implications to runoff and will consider the possible implications of change in snow and the observed later, and reduced, snowmelt runoff observed at Trail Valley and Havikpak Creeks.

  5. Crustal structure and tectonic framework of the Canadian Arctic margin: New insights on the development of the Amerasia Basin

    NASA Astrophysics Data System (ADS)

    Oakey, G. N.; Saltus, R. W.; Chian, D.; Jackson, H. R.; Shimeld, J.; Brozena, J. M.; Funck, T.; Dahl-Jensen, T.

    2013-12-01

    A significant volume of new Arctic geophysical data have been collected over the last decade during collaborative Canadian, American, and Danish research expeditions. These data have been integrated with pre-existing geophysical data sets (e.g., US Naval Research Lab airborne gravity and magnetic surveys) to constrain models for the crustal structure and tectonic evolution of the Amerasia Basin. 2-D gravity and magnetic models have been generated for cross-sections of the Canadian margin, Chukchi Plateau, Alpha Ridge and Lomonosov Ridge. The models are constrained using seismic reflection and refraction data. The models illustrate the variability of different segments of the rifted margins as well as the distribution of magnetized crust and volcanic units. Density values for all of the models are based on standard velocity-density relationships. The models support the velocity analysis of the sonobuoy data that true oceanic crust is present only in a narrow central portion of Canada Basin and that most of the basin is underlain by hyper-extended continental crust and/or 'transitional' crust with localized high-velocity/density sub-crustal layers. Moho depths beneath Canada Basin range from 18 to 22 km. Moho depths beneath the Alpha Ridge are considerably deeper (25 to 30 km) than those in the adjacent Canada Basin. The upper crust of Alpha Ridge is modeled with continental densities in the upper crust underlain by a thick lower crust with an intermediate density. This crustal character is consistent with the formation of the Alpha Ridge by intrusion of a large igneous province (the High Arctic Large Igneous Province - HALIP) into continental crust.

  6. Ice-atmosphere interactions in the Canadian High Arctic: Implications for the thermo-mechanical evolution of terrestrial ice masses

    NASA Astrophysics Data System (ADS)

    Wohlleben, Trudy M. H.

    Canadian High Arctic terrestrial ice masses and the polar atmosphere evolve codependently, and interactions between the two systems can lead to feedbacks, positive and negative. The two primary positive cryosphere-atmosphere feedbacks are: (1) The snow/ice-albedo feedback (where area changes in snow and/or ice cause changes in surface albedo and surface air temperatures, leading to further area changes in snow/ice); and (2) The elevation - mass balance feedback (where thickness changes in terrestrial ice masses cause changes to atmospheric circulation and precipitation patterns, leading to further ice thickness changes). In this thesis, numerical experiments are performed to: (1) quantify the magnitudes of the two feedbacks for chosen Canadian High Arctic terrestrial ice masses; and (2) to examine the direct and indirect consequences of surface air temperature changes upon englacial temperatures with implications for ice flow, mass flux divergence, and topographic evolution. Model results show that: (a) for John Evans Glacier, Ellesmere Island, the magnitude of the terrestrial snow/ice-albedo feedback can locally exceed that of sea ice on less than decadal timescales, with implications for glacier response times to climate perturbations; (b) although historical air temperature changes might be the direct cause of measured englacial temperature anomalies in various glacier and ice cap accumulation zones, they can also be the indirect cause of their enhanced diffusive loss; (c) while the direct result of past air temperature changes has been to cool the interior of John Evans Glacier, and its bed, the indirect result has been to create and maintain warm (pressure melting point) basal temperatures in the ablation zone; and (d) for Devon Ice Cap, observed mass gains in the northwest sector of the ice cap would be smaller without orographic precipitation and the mass balance---elevation feedback, supporting the hypothesis that this feedback is playing a role in the

  7. Optical Characterisation of Suspended Particles in the Mackenzie River Plume (Canadian Arctic Ocean) and Implications for Ocean Colour Remote Sensing

    NASA Technical Reports Server (NTRS)

    Doxaran, D.; Ehn, J.; Belanger, S.; Matsuoka, A.; Hooker, S.; Babin, M.

    2012-01-01

    Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future

  8. Arctic and Offshore Research Subprogram: Reducing the uncertainties about producing oil and gas in the Alaskan Arctic

    SciTech Connect

    Not Available

    1983-10-01

    In assessing the research. The needs for the Arctic and Offshore Research (AOR) Subprogram, Morgantown Energy Technology Center with the DOE Fossil Energy Office of Oil, Gas, and Shale Technology, developed a 5-year plan that includes the following activities: (1) AOR data base development and coordination; (2) ice research; (3) seafloor soils research; and (4) subice arctic research. The DOE Arctic and Offshore Research Subprogram was initiated in FY 83, the major programming activities were performed in January and February 1983, and the program evolved to its present form by the conclusion of FY 83. The current program activities have included determining the various Arctic bibliographic data bases and initiating most pieces of the research described above (except multi-year ice properties, pipeline research, and subice feasibility studies. The seismic-measurements study continues the work initiated by the Energy Research and Development Administration, updated with an Arctic emphasis. The FY 83 accomplishments include redesigning the seafloor earthquake measurements system (SEMS) and assessing the preliminary Alaska site for potential SEMS deployment. 1 reference, 1 figure, 9 tables.

  9. Benthic Food Web Structure across the Canadian Arctic Ocean: Insights from stable isotopes and the IP25 biomarker

    NASA Astrophysics Data System (ADS)

    Friscourt, N.; Archambault, P.; Masse, G.; Nozais, C.

    2016-02-01

    In recent decades, the Arctic Ocean has undergone unprecedented changes, such as an increase in the surface temperature and a reduction of sea ice cover. These changes may cause variations in the intensity and spatial distribution of primary production and the nature of pelagic-benthic coupling. This could affect the amount and quality of organic matter that settles onto the seafloor, and the benthic communities that feed upon it. The objectives of this study were i) to describe the trophic structure and resilience of regional benthic food webs using stable carbon and nitrogen isotope analyses and ii) to evaluate the significance of ice algae in the diet of benthic communities using the sea ice proxy IP25. The study area extends from the North Water Polynya to the Chukchi Sea across five geographic regions (North Water Polynya, Canadian Archipelago, Amundsen Gulf, Beaufort Sea and Chukchi Sea) based on environmental factors. To reach these objectives, we collected particulate organic matter (POM), sediments and zoobenthic samples from July to October 2014 aboard the CCGS Amundsen. Stable isotope and IP25 data, the trophic structure within regions and comparison between regions will be presented. Potential impacts of climate change and human activities on benthic ecosystems in the Arctic are still difficult to assess because of the lack of baseline data. The baseline data once provided will enable us to make further predictions on how these changes may affect benthic food web structure.

  10. Metagenomic survey of the taxonomic and functional microbial communities of seawater and sea ice from the Canadian Arctic

    PubMed Central

    Yergeau, Etienne; Michel, Christine; Tremblay, Julien; Niemi, Andrea; King, Thomas L.; Wyglinski, Joanne; Lee, Kenneth; Greer, Charles W.

    2017-01-01

    Climate change has resulted in an accelerated decline of Arctic sea ice since 2001 resulting in primary production increases and prolongation of the ice-free season within the Northwest Passage. The taxonomic and functional microbial community composition of the seawater and sea ice of the Canadian Arctic is not very well known. Bacterial communities from the bottom layer of sea ice cores and surface water from 23 locations around Cornwallis Island, NU, Canada, were extensively screened. The bacterial 16S rRNA gene was sequenced for all samples while shotgun metagenomics was performed on selected samples. Bacterial community composition showed large variation throughout the sampling area both for sea ice and seawater. Seawater and sea ice samples harbored significantly distinct microbial communities, both at different taxonomic levels and at the functional level. A key difference between the two sample types was the dominance of algae in sea ice samples, as visualized by the higher relative abundance of algae and photosynthesis-related genes in the metagenomic datasets and the higher chl a concentrations. The relative abundance of various OTUs and functional genes were significantly correlated with multiple environmental parameters, highlighting many potential environmental drivers and ecological strategies. PMID:28176868

  11. Contribution of subsurface chlorophyll maxima to primary production in the coastal Beaufort Sea (Canadian Arctic): A model assessment

    NASA Astrophysics Data System (ADS)

    Martin, Johannie; Dumont, Dany; Tremblay, Jean-Éric

    2013-11-01

    Previous comprehensive investigations of the Canadian Arctic revealed that subsurface chlorophyll maxima (SCM) are widespread and long-lived structures that can contribute significantly to daily primary production in the water column. However, estimating the annual contribution of SCM to production with in situ or remote-sensing approaches is challenging in the high Arctic. For this reason and to estimate the impacts of fluctuating or changing environmental conditions on SCM, a numerical approach combining a turbulence model and an ecosystem model was implemented for the coastal Beaufort Sea. An ensemble analysis of simulations suggested that SCM contribute 65-90% of total annual primary production and that this proportion is weakly affected by ice regime, winter nitrogen (N) concentration, parameter values determining phytoplankton growth and decay or the physical forcing imposed, all varying within realistic values. Due to the persistent association between the SCM and the shallow nitracline, the pelagic ecosystem of the coastal Beaufort Sea is apparently characterized by a high ratio of new to total production, contrasting with the common assumption that oligotrophic systems are predominantly supported by recycled N and regenerated production. This study demonstrated that the use of a simple model in combination with in situ data leads to novel insights into biogeochemical processes that are otherwise very difficult to measure and track.

  12. Contaminants in a soil-plant-lemming food chain system at a military radar site in the Canadian Arctic

    SciTech Connect

    Dushenko, W.T.; Bright, D.A.; Grundy, S.L.; Reimer, K.J.

    1995-12-31

    Environmental assessment and impact studies have been conducted at Distant Early Warning (DEW) Line and other radar sites across the Canadian Arctic and Labrador, as well as Arctic background locations since 1989. Some of the major contaminants found in soils and plants in the vicinity of the stations include PCBs and inorganic elements such as lead, copper and zinc. The impact of these contaminants at higher levels of the food chain were examined using a soil-plant-lemming system in a sewage outfall (containing high soil concentrations of contaminants) and background areas at a radar site located at Cambridge Bay, NWT. Concentrations of PCBs in tissue samples from the sewage outfall were all significantly larger than background values with averages, in some cases, differing by an order of magnitude or more. Although the average PCB concentration declines from soils (average 1,600 ppb) to plants (average 9.3 ppb) in the outfall, plant-herbivore food chain biomagnification is indicated by a 6.5 fold increase in PCB concentration between whole lemming tissues (average 61 ppb) and plants. Levels in liver tissue were double this value (123 ppb) being comparable to values reported for predators of this species. The implications of these levels are discussed in terms of ecosystem toxicity using congener specific analysis.

  13. Under-ice ambient noise in Eastern Beaufort Sea, Canadian Arctic, and its relation to environmental forcing.

    PubMed

    Kinda, G Bazile; Simard, Yvan; Gervaise, Cédric; Mars, Jérome I; Fortier, Louis

    2013-07-01

    This paper analyzes an 8-month time series (November 2005 to June 2006) of underwater noise recorded at the mouth of the Amundsen Gulf in the marginal ice zone of the western Canadian Arctic when the area was >90% ice covered. The time-series of the ambient noise component was computed using an algorithm that filtered out transient acoustic events from 7-min hourly recordings of total ocean noise over a [0-4.1] kHz frequency band. Under-ice ambient noise did not respond to thermal changes, but showed consistent correlations with large-scale regional ice drift, wind speed, and measured currents in upper water column. The correlation of ambient noise with ice drift peaked for locations at ranges of ~300 km off the mouth of the Amundsen Gulf. These locations are within the multi-year ice plume that extends westerly along the coast in the Eastern Beaufort Sea due to the large Beaufort Gyre circulation. These results reveal that ambient noise in Eastern Beaufort Sea in winter is mainly controlled by the same meteorological and oceanographic forcing processes that drive the ice drift and the large-scale circulation in this part of the Arctic Ocean.

  14. Distribution and diet of larval and juvenile Arctic cod ( Boreogadus saida) in the shallow Canadian Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Walkusz, Wojciech; Paulic, Joclyn E.; Williams, William J.; Kwasniewski, Slawomir; Papst, Michael H.

    2011-02-01

    The distribution and diet of larval and juvenile Arctic cod ( Boreogadus saida) were studied during summer 2005 in the coastal Canadian Beaufort Sea. A total of 275 individuals were captured and the highest abundance was observed at station depths of 20-30 m. This corresponds well with the location of the frontal zone where the Mackenzie River plume water and open sea water meet. Diet examinations were performed on 220 Arctic cod, which were found undamaged from sampling. We observed a gradual decrease in prey number per fish and increase in prey size as larvae grew which corresponded to a shift from Rotifera and nauplii towards larger copepodid stages. However, at all sizes, the larvae remain generalists and feed on a broad range of organisms. Environmental changes due to climate warming could have a two-fold impact on fish larvae feeding in the studied region. First, the potential for increased primary production may lead to increased zooplankton production that may impact the feeding and nutrition positively. On the other hand, greater discharge of turbid water from the Mackenzie River may reduce light penetration in the water column that may negatively influence the ability of visual predators to successively forage.

  15. Metagenomic survey of the taxonomic and functional microbial communities of seawater and sea ice from the Canadian Arctic.

    PubMed

    Yergeau, Etienne; Michel, Christine; Tremblay, Julien; Niemi, Andrea; King, Thomas L; Wyglinski, Joanne; Lee, Kenneth; Greer, Charles W

    2017-02-08

    Climate change has resulted in an accelerated decline of Arctic sea ice since 2001 resulting in primary production increases and prolongation of the ice-free season within the Northwest Passage. The taxonomic and functional microbial community composition of the seawater and sea ice of the Canadian Arctic is not very well known. Bacterial communities from the bottom layer of sea ice cores and surface water from 23 locations around Cornwallis Island, NU, Canada, were extensively screened. The bacterial 16S rRNA gene was sequenced for all samples while shotgun metagenomics was performed on selected samples. Bacterial community composition showed large variation throughout the sampling area both for sea ice and seawater. Seawater and sea ice samples harbored significantly distinct microbial communities, both at different taxonomic levels and at the functional level. A key difference between the two sample types was the dominance of algae in sea ice samples, as visualized by the higher relative abundance of algae and photosynthesis-related genes in the metagenomic datasets and the higher chl a concentrations. The relative abundance of various OTUs and functional genes were significantly correlated with multiple environmental parameters, highlighting many potential environmental drivers and ecological strategies.

  16. Mesoscale distribution and functional diversity of picoeukaryotes in the first-year sea ice of the Canadian Arctic.

    PubMed

    Piwosz, Kasia; Wiktor, Józef Maria; Niemi, Andrea; Tatarek, Agnieszka; Michel, Christine

    2013-08-01

    Sea ice, a characteristic feature of polar waters, is home to diverse microbial communities. Sea-ice picoeukaryotes (unicellular eukaryotes with cell size <3 μm) have received little attention compared with diatoms that dominate the spring bloom in Arctic first-year sea ice. Here, we investigated the abundance of all picoeukaryotes, and of 11 groups (chlorophytes, cryptophytes, bolidophytes, haptophytes, Pavlovaphyceae, Phaeocystis spp., pedinellales, stramenopiles groups MAST-1, MAST-2 and MAST-6 and Syndiniales Group II) at 13 first-year sea-ice stations localized in Barrow Strait and in the vicinity of Cornwallis Island, Canadian Arctic Archipelago. We applied Catalyzed Reporter Deposition-Fluorescence In Situ Hybridization to identify selected groups at a single cell level. Pavlovaphyceae and stramenopiles from groups MAST-2 and MAST-6 were for the first time reported from sea ice. Total numbers of picoeukaryotes were significantly higher in the vicinity of Cornwallis Island than in Barrow Strait. Similar trend was observed for all the groups except for haptophytes. Chlorophytes and cryptophytes were the dominant plastidic, and MAST-2 most numerous aplastidic of all the groups investigated. Numbers of total picoeukaryotes, chlorophytes and MAST-2 stramenopiles were positively correlated with the thickness of snow cover. All studied algal and MAST groups fed on bacteria. Presence of picoeukaryotes from various trophic groups (mixotrophs, phagotrophic and parasitic heterotrophs) indicates the diverse ecological roles picoeukaryotes have in sea ice. Yet, >50% of total sea-ice picoeukaryote cells remained unidentified, highlighting the need for further study of functional and phylogenetic sea-ice diversity, to elucidate the risks posed by ongoing Arctic changes.

  17. Predation pressure by avian predators suggests summer limitation of small-mammal populations in the Canadian Arctic.

    PubMed

    Therrien, J F; Gauthier, G; Korpimäki, E; Bêty, J

    2014-01-01

    Predation has been suggested to be especially important in simple food webs and less productive ecosystems such as the arctic tundra, but very few data are available to evaluate this hypothesis. We examined the hypothesis that avian predators could drive the population dynamics of two cyclic lemming species in the Canadian Arctic. A dense and diverse suite of predatory birds, including the Snowy Owl (Bubo scandiacus), the Rough-legged Hawk (Buteo lagopus), and the Long-tailed Jaeger (Stercorarius longicaudus), inhabits the arctic tundra and prey on collared (Dicrostonyx groenlandicus) and brown (Lemmus trimucronatus) lemmings during the snow-free period. We evaluated the predation pressure exerted by these predators by combining their numerical (variation in breeding and fledgling numbers) and functional (variation in diet and daily consumption rates) responses to variations in lemming densities over the 2004-2010 period. Breeding density and number of fledglings produced by the three main avian predators increased sharply without delay in response to increasing lemming densities. The proportion of collared lemmings in the diet of those predators was high at low lemming density (both species) but decreased as lemming density increased. However, we found little evidence that their daily consumption rates vary in relation to changes in lemming density. Total consumption rate by avian predators initially increased more rapidly for collared lemming but eventually leveled off at a much higher value for brown lemmings, the most abundant species at our site. The combined daily predation rate of avian predators exceeded the maximum daily potential growth rates of both lemming species except at the highest recorded densities for brown lemmings. We thus show, for the first time, that predation pressure exerted without delay by avian predators can limit populations of coexisting lemming species during the snow-free period, and thus, that predation could play a role in the

  18. Mesoscale distribution and functional diversity of picoeukaryotes in the first-year sea ice of the Canadian Arctic

    PubMed Central

    Piwosz, Kasia; Wiktor, Józef Maria; Niemi, Andrea; Tatarek, Agnieszka; Michel, Christine

    2013-01-01

    Sea ice, a characteristic feature of polar waters, is home to diverse microbial communities. Sea-ice picoeukaryotes (unicellular eukaryotes with cell size <3 μm) have received little attention compared with diatoms that dominate the spring bloom in Arctic first-year sea ice. Here, we investigated the abundance of all picoeukaryotes, and of 11 groups (chlorophytes, cryptophytes, bolidophytes, haptophytes, Pavlovaphyceae, Phaeocystis spp., pedinellales, stramenopiles groups MAST-1, MAST-2 and MAST-6 and Syndiniales Group II) at 13 first-year sea-ice stations localized in Barrow Strait and in the vicinity of Cornwallis Island, Canadian Arctic Archipelago. We applied Catalyzed Reporter Deposition–Fluorescence In Situ Hybridization to identify selected groups at a single cell level. Pavlovaphyceae and stramenopiles from groups MAST-2 and MAST-6 were for the first time reported from sea ice. Total numbers of picoeukaryotes were significantly higher in the vicinity of Cornwallis Island than in Barrow Strait. Similar trend was observed for all the groups except for haptophytes. Chlorophytes and cryptophytes were the dominant plastidic, and MAST-2 most numerous aplastidic of all the groups investigated. Numbers of total picoeukaryotes, chlorophytes and MAST-2 stramenopiles were positively correlated with the thickness of snow cover. All studied algal and MAST groups fed on bacteria. Presence of picoeukaryotes from various trophic groups (mixotrophs, phagotrophic and parasitic heterotrophs) indicates the diverse ecological roles picoeukaryotes have in sea ice. Yet, >50% of total sea-ice picoeukaryote cells remained unidentified, highlighting the need for further study of functional and phylogenetic sea-ice diversity, to elucidate the risks posed by ongoing Arctic changes. PMID:23514779

  19. Factors Driving Potential Ammonia Oxidation in Canadian Arctic Ecosystems: Does Spatial Scale Matter?

    PubMed Central

    Banerjee, Samiran

    2012-01-01

    Ammonia oxidation is a major process in nitrogen cycling, and it plays a key role in nitrogen limited soil ecosystems such as those in the arctic. Although mm-scale spatial dependency of ammonia oxidizers has been investigated, little is known about the field-scale spatial dependency of aerobic ammonia oxidation processes and ammonia-oxidizing archaeal and bacterial communities, particularly in arctic soils. The purpose of this study was to explore the drivers of ammonia oxidation at the field scale in cryosols (soils with permafrost within 1 m of the surface). We measured aerobic ammonia oxidation potential (both autotrophic and heterotrophic) and functional gene abundance (bacterial amoA and archaeal amoA) in 279 soil samples collected from three arctic ecosystems. The variability associated with quantifying genes was substantially less than the spatial variability observed in these soils, suggesting that molecular methods can be used reliably evaluate spatial dependency in arctic ecosystems. Ammonia-oxidizing archaeal and bacterial communities and aerobic ammonia oxidation were spatially autocorrelated. Gene abundances were spatially structured within 4 m, whereas biochemical processes were structured within 40 m. Ammonia oxidation was driven at small scales (<1m) by moisture and total organic carbon, whereas gene abundance and other edaphic factors drove ammonia oxidation at medium (1 to 10 m) and large (10 to 100 m) scales. In these arctic soils heterotrophs contributed between 29 and 47% of total ammonia oxidation potential. The spatial scale for aerobic ammonia oxidation genes differed from potential ammonia oxidation, suggesting that in arctic ecosystems edaphic, rather than genetic, factors are an important control on ammonia oxidation. PMID:22081570

  20. The nature and fate of natural resins in the geosphere VI. Analysis of fossil resins from Axel Heiberg Island Canadian Arctic

    SciTech Connect

    Anderson, K.B. |; LePage, B.A.

    1995-06-01

    Ambers are well known and abundant in terrestrial sediments all over the world; however, due largely to the absence of definite morphological characteristics, the precise botanical origin of most amber samples, are at best, often a matter of speculation. This has severely restricted the usefulness of amber in paleobotanical and paleoecological interpretations. The molecular composition and structural characteristics of fossil resins however, may preserve evidence of their botanical origin, which could be of great value in both geochemical, paleobotanical, and paleoenvironmental studies. The remains of a number of exceptionally well-preserved Taxodiaceae-dominated swamp-forest communities have been identified in the sediments of the middle Eocene (45 million years old) Buchanan Lake Formation of Axel Heiberg Island, Canadian Arctic Archipelago. The amber collected from these ancient in situ forests provides a unique opportunity to characterize these resins chemically and taxonomically. Resinite associated with Metasequoia, Pinus and Pseudolarix has been characterized using Pyrolysis-Gas Chromatography-Mass Spectrometry. This method provides a direct analysis of the molecular structure and composition of the resin. In several cases, both bled resin and cone-resin samples have been characterized. The results of these analyses are presented and discussed. The implications of these results for the botanical origins of other ambers represented in the fossil record (including succinite) will also be discussed.

  1. Evaluation and control mechanisms of volume and freshwater export through the Canadian Arctic Archipelago in a high-resolution pan-Arctic ice-ocean model

    NASA Astrophysics Data System (ADS)

    McGeehan, Timothy; Maslowski, Wieslaw

    2012-03-01

    This study examined the 1979-2004 volume and freshwater fluxes through the Canadian Arctic Archipelago (CAA) and into the Labrador Sea using a high resolution (˜9 km) coupled ice-ocean model of the pan-Arctic region to provide a reference, compare with limited observational estimates, and investigate control mechanisms of this exchange. The 26-year mean volume and freshwater fluxes through Nares Strait were 0.77 Sv ± 0.17 Sv and 10.38 mSv ± 1.67 mSv respectively, while those through Lancaster Sound amounted to 0.76 Sv ± 0.12 Sv and 48.45 mSv ± 7.83 mSv respectively. The 26-year mean volume and freshwater fluxes through Davis Strait were 1.55 Sv ± 0.29 Sv and 62.66 mSv ± 11.67 mSv while the modeled Fram Strait branch provided very little (˜2%) freshwater into the Labrador Sea compared to the total CAA input. Compared to available observations, the model provides reasonable volume and freshwater fluxes, as well as sea ice thickness and concentration in the CAA. In Nares Strait and Lancaster Sound, volume flux anomalies were controlled by the sea surface height (SSH) gradient anomalies along the straits and freshwater anomalies were highly correlated with the volume anomalies. At least half of the variance in the time series of SSH gradient anomaly was due to SSH anomalies in northern Baffin Bay. The West Greenland Current (WGC) exhibits seasonality, with cross shelf flow (into the Labrador Sea) peaking in January/February/March, while reducing the northward flow across eastern Davis Strait. We hypothesize that the eddy-reduced northward flow of WGC results in the lower volume and SSH in Baffin Bay. This maximizes the SSH gradients between the Arctic Ocean and Baffin Bay, leading to maximum winter volume fluxes through Nares Strait and Lancaster Sound. Model limitations include the insufficient spatial resolution of atmospheric forcing (especially to account for the effects of local topography), the representation of river runoff into Hudson Bay and coastal

  2. Chapter 9: Oil and gas resource potential north of the Arctic Circle

    USGS Publications Warehouse

    Gautier, D.L.; Bird, K.J.; Charpentier, R.R.; Grantz, A.; Houseknecht, D.W.; Klett, T.R.; Moore, T.E.; Pitman, J.K.; Schenk, C.J.; Schuenemeyer, J.H.; Sorensen, K.; Tennyson, Marilyn E.; Valin, Z.C.; Wandrey, C.J.

    2011-01-01

    The US Geological Survey recently assessed the potential for undiscovered conventional petroleumin the Arctic. Using a new map compilation of sedimentary elements, the area north of the Arctic Circle was subdivided into 70 assessment units, 48 of which were quantitatively assessed. The Circum-Arctic Resource Appraisal (CARA) was a geologically based, probabilistic study that relied mainly on burial history analysis and analogue modelling to estimate sizes and numbers of undiscovered oil and gas accumulations. The results of the CARA suggest the Arctic is gas-prone with an estimated 770-2990 trillion cubic feet of undiscovered conventional natural gas, most of which is in Russian territory. On an energy-equivalent basis, the quantity of natural gas ismore than three times the quantity of oil and the largest undiscovered gas eld is expected to be about 10 times the size of the largest undiscovered oil eld. In addition to gas, the gas accumulationsmay contain an estimated 39 billion barrels of liquids. The South Kara Sea is themost prospective gas assessment unit, but giant gas elds containingmore than 6 trillion cubic feet of recoverable gas are possible at a 50%chance in 10 assessment units. Sixty per cent of the estimated undiscovered oil resource is in just six assessment units, of which the Alaska Platform, with 31%of the resource, is the most prospective. Overall, the Arctic is estimated to contain between 44 and 157 billion barrels of recoverable oil. Billion barrel oil elds are possible at a 50%chance in seven assessment units.Undiscovered oil resources could be signicant to the Arctic nations, but are probably not sufcient to shift the world oil balance away from the Middle East. ?? 2011 The Geological Society of London.

  3. Greenhouse Gas Exchange in Small Arctic Thaw Ponds

    NASA Astrophysics Data System (ADS)

    Laurion, I.; Bégin, P. N.; Bouchard, F.; Preskienis, V.

    2014-12-01

    Arctic lakes and ponds can represent up to one quarter of the land surface in permafrost landscapes, particularly in lowland tundra landscapes characterized by ice wedge organic polygons. Thaw ponds can be defined as the aquatic ecosystems associated to thawing of organic soils, either resulting from active layer processes and located above low-center peat polygons (hereafter low-center polygonal or LCP ponds), or resulting from thermokarst slumping above melting ice wedges linked to the accelerated degradation of permafrost (hereafter ice-wedge trough or IWT ponds). These ponds can merge together forming larger water bodies, but with relatively stable shores (hereafter merged polygonal or MPG ponds), and with limnological characteristics similar to LCP ponds. These aquatic systems are very small and shallow, and present a different physical structure than the larger thermokarst lakes, generated after years of development and land subsidence. In a glacier valley on Bylot Island, Nunavut, Canada, thermokarst and kettle lakes together represent 29% of the aquatic area, with a thermal profile resembling those of more standard arctic lakes (mixed epilimnion). The IWT ponds (44% of the area) are stratified for a large fraction of the summer despite their shallowness, while LCP and MPG ponds (27% of the area) show a more homogeneous water column. This will affect gas exchange in these diverse aquatic systems, in addition to their unique microbiota and organic carbon lability that control the production and consumption rates of greenhouse gases. The stratification in IWT ponds generates hypoxic conditions at the bottom, and together with the larger availability of organic carbon, stimulates methanogenesis and limits the mitigating action of methanotrophs. Overall, thaw ponds are largely supersaturated in methane, with IWT ponds dominating the emissions in this landscape (92% of total aquatic emissions estimated for the same valley), and they present large variations in

  4. Multiple climatic signals inferred from the varved sediments of a coastal lake in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Amann, Benjamin; Lamoureux, Scott F.

    2016-04-01

    The Arctic is extremely sensitive to climate change, and an influential part of the global climate system. However, the assessment of climate change and impacts from the Arctic remains a challenge mainly due to short and sparse meteorological records. In this context, data from natural paleoclimate archives are fundamental to place climate variability into perspective and assess the sensitivity of Earth's climate to natural and anthropogenic forcings. In particular, Arctic lakes are excellent potential archives. They are sensitive to extreme seasonal variations in surface processes and have a limited direct human impact. Nevertheless, the study of Arctic lakes is an analytical and technical challenge because: (i) limnological information are often lacking due to difficult accessibility; (ii) 210Pb inventories are low and terrestrial macrofossils for 14C dating are rare, which limits the development of precise sediment chronologies; and (iii) sediment accumulation rates are often low, which may restrict the temporal resolution and length of the paleoclimate records. Here, we present a high-resolution record from the varved sediments (annual laminations) of a saline coastal lake located in the Canadian High Arctic (unofficial name Chevalier Lake; Melville Island, NT). The particular interest of this location is the catchment area: 152 times larger than the lake area (Ac = 350 km²; AL = 2.3 km²). This particularity generates high sedimentation rates, atypical of previously studied arctic lakes. Two sediment cores were recovered from the centre and a more proximal zone of the lake. We used microstratigraphy supported by X-ray fluorescence data (Zr/K for particle size, Fe/Rb for the winter clay cap distinction) to develop a precise and cross-dated varve chronology covering the last 400 years. Dating of the uppermost section could be validated with preliminary 137Cs data. Stratigraphical analysis reveals the presence of three sediment units within the meter

  5. Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core.

    PubMed

    Spolaor, Andrea; Vallelonga, Paul; Turetta, Clara; Maffezzoli, Niccolò; Cozzi, Giulio; Gabrieli, Jacopo; Barbante, Carlo; Goto-Azuma, Kumiko; Saiz-Lopez, Alfonso; Cuevas, Carlos A; Dahl-Jensen, Dorthe

    2016-09-21

    Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called "bromine explosions" and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3 °C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2 °C global average warming target of the recent COP21 Paris climate agreement.

  6. Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core

    PubMed Central

    Spolaor, Andrea; Vallelonga, Paul; Turetta, Clara; Maffezzoli, Niccolò; Cozzi, Giulio; Gabrieli, Jacopo; Barbante, Carlo; Goto-Azuma, Kumiko; Saiz-Lopez, Alfonso; Cuevas, Carlos A.; Dahl-Jensen, Dorthe

    2016-01-01

    Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called “bromine explosions” and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3 °C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2 °C global average warming target of the recent COP21 Paris climate agreement. PMID:27650478

  7. Building Capacity: The University of the Arctic and Its Northern Canadian Context.

    ERIC Educational Resources Information Center

    Senkpiel, Aron

    2000-01-01

    A proposed university in the circumpolar North would have undergraduate and graduate programs, be interdisciplinary, collaborate with other Northern countries and universities, and offer a circumpolar course to develop understanding of the Arctic. After many false starts, most components are already in place; all that is needed is determination,…

  8. Building Capacity: The University of the Arctic and Its Northern Canadian Context.

    ERIC Educational Resources Information Center

    Senkpiel, Aron

    2000-01-01

    A proposed university in the circumpolar North would have undergraduate and graduate programs, be interdisciplinary, collaborate with other Northern countries and universities, and offer a circumpolar course to develop understanding of the Arctic. After many false starts, most components are already in place; all that is needed is determination,…

  9. Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core

    NASA Astrophysics Data System (ADS)

    Spolaor, Andrea; Vallelonga, Paul; Turetta, Clara; Maffezzoli, Niccolò; Cozzi, Giulio; Gabrieli, Jacopo; Barbante, Carlo; Goto-Azuma, Kumiko; Saiz-Lopez, Alfonso; Cuevas, Carlos A.; Dahl-Jensen, Dorthe

    2016-09-01

    Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called “bromine explosions” and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3 °C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2 °C global average warming target of the recent COP21 Paris climate agreement.

  10. Ocean optical measurements—II. Statistical analysis of data from Canadian eastern Arctic waters

    NASA Astrophysics Data System (ADS)

    Topliss, B. J.; Miller, J. R.; Horne, E. P. W.

    1989-02-01

    The attenuation of light in Arctic waters was found to be controlled by chlorophyll pigment and dissolved material with a possible contribution from suspended particulate matter. The potential dependence of the attenuation coefficient on pigment concentration, depth and material type was statistically investigated to evaluate these individual, but intercorrelated, contributions. When the variation of dissolved material with depth was selected as a separation criteria for the intercorrelated in situ variables the statistical analysis suggested a concentration dependence for the specific attenuation coefficient of chlorophyll pigments. A non-linear attenuation/pigment relationship for the Arctic data, governed by concentration and proportion of phaeophytin to chlorophyll, was found to be consistent with clear water data from the open ocean as well as from turbid waters on the Grand Banks. Although only approximately 25% of available light was absorbed by chlorophyll a pigment itself, the under-water spectrum was modified by these pigments in a manner similar to that occurring in clear open ocean waters. Scattering calculations gave large specific back-scattering values for low pigment concentrations in Arctic waters as well as for waters from an inshore glacial fjord, posing potential interpretation problems for remote sensing applications. In contrast scattering calculations for high pigment concentrations from the Arctic implied that potentially useful information might be extracted from high latitude imagery.

  11. Changes in cold tolerance due to a 14-day stay in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Livingstone, S. D.; Romet, T.; Keefe, A. A.; Nolan, R. W.

    1996-12-01

    Responses to cold exposure tests both locally and of the whole body were examined in subjects who stayed in the Arctic (average maximum and minimum temperatures -11 and -21° C respectively) for 14 days of skiing and sleeping in tents. These changes were compared to responses in subjects living working in Ottawa, Canada (average max. and min. temperatures -5 and -11° C respectively). The tests were done before the stay in the Arctic (Pre), immediately after the return (Post 1) and approximately 32 days after the return (Post 2). For the whole-body cold exposure each subject, wearing only shorts and lying on a rope mesh cot, was exposed to an ambient temperature of 10° C. There was no consistent response in the changes of metabolic or body temperature to this exposure in either of groups and, in addition, the changes over time were variable. Cold induced vasodilatation (CIVD) was determined by measuring temperature changes in the middle finger of the nondominant hand upon immersion in ice water for 30 min. CIVD was depressed after the Arctic exposure whilst during the Post 2 testing, although variable, did not return to the Pre values; the responses of the control group were similar. These results indicate that normal seasonal changes may be as important in adaptation as a stay in the Arctic. Caution is advised in the separation of seasonal effects when examining the changes in adaptation after exposure to a cold environment.

  12. Composition and meteorological changes associated with a strong stratospheric intrusion event in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoyi; Strong, Kimberly; Conway, Stephanie; Tarasick, David; Osman, Mohammed; Richter, Andreas; Blechschmidt, Anne; Manney, Gloria

    2015-04-01

    Stratosphere-troposphere exchange (STE) provides a mechanism for trace gas transport between the lower stratosphere and the troposphere. Intense downward stratospheric intrusions may significantly affect the oxidizing capacity of the troposphere. Most STE events occur in tropical and mid-latitude regions, with less known about STE in the polar regions. In this work, we present an observation and modelling study of a strong stratospheric intrusion in the high Arctic (Eureka, 80°N) in March 2013, which led to an increase of total ozone and BrO columns observed by both ground-based and satellite instruments. The meteorological conditions for this event were similar to those observed for STEs associated with cold fronts. Before the cold front arrived at Eureka, the surface temperature first increased from -25.3°C (25 March 13:00 UTC) to -14.5°C (27 March 20:00 UTC) and then dropped to -36.4°C (29 March 6:00 UTC) after the front passed by. Meanwhile, the ground-level pressure decreased from 103.8 kPa to 101.8 kPa, then rose back to 102.6 kPa. Ozonesonde data (27 March 23:15 UTC) showed unusually high ozone (>100 ppbv) above ~3 km altitude, while the relative humidity profile indicated that the airmass was of stratospheric origin (very low relative humidity). The thermal tropopause height was ~9 km, based on a uniform lapse rate of 3.9 K/km from surface to 9 km. From ECMWF Interim data, the airmass with high relative potential vorticity (4 pvu) extended down to 3 km. In addition, HYSPLIT model ensemble back-trajectories show a clear Rossby wave signature in the upper troposphere during this event, which could explain the intrusion. However, there are no strong downwelling layers along the trajectories, which indicates that the intrusion may have occurred close to Eureka. Trace gas composition data from three ground-based spectrometers and the GOME-2 satellite instrument are presented in this work. Ozone vertical column densities (VCDs) measured by two Zenith

  13. Observations of a bromine explosion event coincident with the arrival of Arctic haze in the Canadian high Arctic

    NASA Astrophysics Data System (ADS)

    Bognar, Kristof; Zhao, Xiaoyi; Strong, Kimberly; Hayes, Patrick L.; Tremblay, Samantha; Chang, Rachel Y.-W.

    2017-04-01

    Exponential build-up of bromine in the polar troposphere is linked to severe multi-day ozone depletion events in springtime. The exact origins of, and the meteorological conditions required for these 'bromine explosions' are, however, not well understood. On March 19-21, 2016, a bromine explosion was detected at Eureka, Nunavut, Canada (80.1°N, 86.4°W). BrO slant column densities were retrieved from measurements made by a Multi-Axis Differential Optical Absorption Spectroscopy spectrometer. Ozonesonde data indicate that a compete depletion of near-surface ozone also took place in the same period. The bromine explosion was initiated by strong winds and blowing snow, while a stable boundary layer returned for the last day of the event. It is likely that bromine release was localized near Eureka, and both the snowpack and aerosols contributed. Scanning Mobility Particle Sizer data show that the bromine enhancement coincided with the onset of an Arctic haze event. This work investigates whether acidification from the haze contributed to the local release of bromine.

  14. Periglacial Landscape Stabilization Following Rapid Permafrost Degradation by Thermo-erosion, Bylot Island, Nunavut, Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Fortier, D.; Godin, E.; Perreault, N.; Levesque, E.

    2010-12-01

    and the subsequent colonization of stabilized slopes by vegetation changed the thermal properties of the soil which resulted in a thinning of the active layer and ground ice aggradation in the upper part of the permafrost. These negative feedback effects contributed to permafrost recovery and ground ice aggradation. The latent heat of this ice-rich zone will act as a buffer to global warming and contributes to the long-term stability of the gullies in the new periglacial landscape. Fortier, D., Allard, M. 2004. Late Holocene Syngenetic Ice-wedge Polygons Development, Bylot Island, Canadian Arctic Archipelago. Canadian Journal of Earth Sciences, 41: 997-1012. Fortier, D., Allard, M., Shur, Y. 2007. Observation of Rapid Drainage System Development by Thermal Erosion of Ice Wedges on Bylot Island, Canadian Arctic Archipelago. Permafrost and Periglacial Processes, 18: 229-243. Godin, E., Fortier, D. (in press) Geomorphology of thermo-erosion gullies - case study from Bylot Island, Nunavut, Canada. Proceedings 6th Canadian Permafrost Conference and 63rd Canadian Geotechnical Conference, Calgary, October 2010.

  15. Submarine groundwater discharge as a possible formation mechanism for permafrost-associated gas hydrate on the circum-Arctic continental shelf

    NASA Astrophysics Data System (ADS)

    Frederick, Jennifer M.; Buffett, Bruce A.

    2016-03-01

    Submarine groundwater discharge (SGD) is a large-scale, buoyancy-driven, offshore flow of terrestrial groundwater. If SGD occurs within the permafrost-bearing sediments of the circum-Arctic shelf, such fluid circulation may transport large amounts of dissolved methane to the circum-Arctic shelf, aiding the formation of permafrost-associated gas hydrate. We investigate the feasibility of this new permafrost-associated gas hydrate formation mechanism with a 2-D, multiphase fluid flow model, using the Canadian Beaufort Shelf as an example. The numerical model includes freeze/thaw permafrost processes and predicts the unsteady, 2-D methane solubility field for hydrate inventory calculations. Model results show that widespread, low-saturation hydrate deposits accumulate within and below submarine permafrost, even if offshore-flowing groundwater is undersaturated in methane gas. While intrapermafrost hydrate inventory varies widely depending on permafrost extent, subpermafrost hydrate stability remains largely intact across consecutive glacial cycles, allowing widespread subpermafrost accumulation over time. Methane gas escape to the sediment surface (atmosphere) is predicted along the seaward permafrost boundary during the early to middle years of each glacial epoch; however, if free gas is trapped within the forming permafrost layer instead, venting may be delayed until ocean transgression deepens the permafrost table during interglacial periods, and may be related to the spatial distribution of observed pingo-like features (PLFs) on the Canadian Beaufort Shelf. Shallow, gas-charged sediments are predicted above the gas hydrate stability zone at the midshelf to shelf edge and the upper slope, where a gap in hydrate stability allows free gas to accumulate and numerous PLFs have been observed.

  16. Some sources and sinks of monomethyl and inorganic mercury on Ellesmere Island in the Canadian High Arctic.

    PubMed

    St Louis, Vincent L; Sharp, Martin J; Steffen, Alexandra; May, Al; Barker, Joel; Kirk, Jane L; Kelly, David J A; Arnott, Shelley E; Keatley, Bronwyn; Smol, John P

    2005-04-15

    We identified some of the sources and sinks of monomethyl mercury (MMHg) and inorganic mercury (HgII) on Ellesmere Island in the Canadian High Arctic. Atmospheric Hg depletion events resulted in the deposition of Hg(II) into the upper layers of snowpacks, where concentrations of total Hg (all forms of Hg) reached over 20 ng/L. However, our data suggest that much of this deposited Hg(II) was rapidly photoreduced to Hg(0) which then evaded back to the atmosphere. As a result, we estimate that net wet and dry deposition of Hg(II) during winter was lower at our sites (0.4-5.9 mg/ha) than wet deposition in more southerly locations in Canada and the United States. We also found quite high concentrations of monomethyl Hg (MMHg) in snowpacks (up to 0.28 ng/L), and at times, most of the Hg in snowpacks was present as MMHg. On the Prince of Wales Icefield nearthe North Water Polynya, we observed a significant correlation between concentrations of Cl and MMHg in snow deposited in the spring, suggesting a marine source of MMHg. We hypothesize that dimethyl Hg fluxes from the ocean to the atmosphere through polynyas and open leads in ice, and is rapidly photolyzed to MMHgCl. We also found that concentrations of MMHg in initial snowmelt on John Evans Glacier (up to 0.24 ng/L) were higher than concentrations of MMHg in the snowpack (up to 0.11 ng/L), likely due to either sublimation of snow or preferential leaching of MMHg from snow during the initial melt phase. This springtime pulse of MMHg to the High Arctic, in conjunction with climate warming and the thinning and melting of sea ice, may be partially responsible for the increase in concentrations of Hg observed in certain Arctic marine mammals in recent decades. Concentrations of MMHg in warm and shallow freshwater ponds on Ellesmere Island were also quite high (up to 3.0 ng/L), leading us to conclude that there are very active regions of microbial Hg(II) methylation in freshwater systems during the short summer season in the

  17. The impact of lower sea-ice extent on Arctic greenhouse-gas exchange

    USGS Publications Warehouse

    Parmentier, Frans-Jan W.; Christensen, Torben R.; Sørensen, Lise Lotte; Rysgaard, Søren; McGuire, A. David; Miller, Paul A.; Walker, Donald A.

    2013-01-01

    In September 2012, Arctic sea-ice extent plummeted to a new record low: two times lower than the 1979–2000 average. Often, record lows in sea-ice cover are hailed as an example of climate change impacts in the Arctic. Less apparent, however, are the implications of reduced sea-ice cover in the Arctic Ocean for marine–atmosphere CO2 exchange. Sea-ice decline has been connected to increasing air temperatures at high latitudes. Temperature is a key controlling factor in the terrestrial exchange of CO2 and methane, and therefore the greenhouse-gas balance of the Arctic. Despite the large potential for feedbacks, many studies do not connect the diminishing sea-ice extent with changes in the interaction of the marine and terrestrial Arctic with the atmosphere. In this Review, we assess how current understanding of the Arctic Ocean and high-latitude ecosystems can be used to predict the impact of a lower sea-ice cover on Arctic greenhouse-gas exchange.

  18. Future emissions from oil, gas, and shipping activities in the Arctic

    NASA Astrophysics Data System (ADS)

    Peters, G. P.; Nilssen, T. B.; Lindholt, L.; Eide, M. S.; Glomsrød, S.; Eide, L. I.; Fuglestvedt, J. S.

    2011-02-01

    The Arctic sea-ice is retreating faster than predicted by climate models and could become ice free during summer this century. The reduced sea-ice extent may effectively "unlock" the Arctic Ocean to increased human activities such as transit shipping and expanded oil and gas production. Travel time between Europe and the north Pacific Region can be reduced by up to 50% with low sea-ice levels and the use of this route could increase substantially as the sea-ice retreats. Oil and gas activities already occur in the Arctic region and given the large undiscovered petroleum resources increased activity could be expected with reduced sea-ice. We use a detailed global energy market model and a bottom-up shipping model with a sea-ice module to construct emission inventories of Arctic shipping and petroleum activities in 2030 and 2050. The emission inventories are on a 1× 1 degree grid and cover both short-lived pollutants and ozone pre-cursors (SO2, NOx, CO, NMVOC, BC, OC) and the long-lived greenhouse gases (CO2, CH4, N2O). We find rapid growth in transit shipping due to increased profitability with the shorter transit times compensating for increased costs in traversing areas of sea-ice. Oil and gas production remains relatively stable leading to reduced emissions from emission factor improvements. The location of oil and gas production moves into locations requiring more ship transport relative to pipeline transport, leading to rapid emissions growth from oil and gas transport via ship. Our emission inventories for the Arctic region will be used as input into chemical transport, radiative transfer, and climate models to quantify the role of Arctic activities in climate change compared to similar emissions occurring outside of the Arctic region.

  19. Differences in mercury bioaccumulation between polar bears (Ursus maritimus) from the Canadian high- and sub-Arctic.

    PubMed

    St Louis, Vincent L; Derocher, Andrew E; Stirling, Ian; Graydon, Jennifer A; Lee, Caroline; Jocksch, Erin; Richardson, Evan; Ghorpade, Sarah; Kwan, Alvin K; Kirk, Jane L; Lehnherr, Igor; Swanson, Heidi K

    2011-07-15

    Polar bears (Ursus maritimus) are being impacted by climate change and increased exposure to pollutants throughout their northern circumpolar range. In this study, we quantified concentrations of total mercury (THg) in the hair of polar bears from Canadian high- (southern Beaufort Sea, SBS) and sub- (western Hudson Bay, WHB) Arctic populations. Concentrations of THg in polar bears from the SBS population (14.8 ± 6.6 μg g(-1)) were significantly higher than in polar bears from WHB (4.1 ± 1.0 μg g(-1)). On the basis of δ(15)N signatures in hair, in conjunction with published δ(15)N signatures in particulate organic matter and sediments, we estimated that the pelagic and benthic food webs in the SBS are ∼ 4.7 and ∼ 4.0 trophic levels long, whereas in WHB they are only ∼ 3.6 and ∼ 3.3 trophic levels long. Furthermore, the more depleted δ(13)C ratios in hair from SBS polar bears relative to those from WHB suggests that SBS polar bears feed on food webs that are relatively more pelagic (and longer), whereas polar bears from WHB feed on those that are relatively more benthic (and shorter). Food web length and structure accounted for ∼ 67% of the variation we found in THg concentrations among all polar bears across both populations. The regional difference in polar bear hair THg concentrations was also likely due to regional differences in water-column concentrations of methyl Hg (the toxic form of Hg that biomagnifies through food webs) available for bioaccumulation at the base of the food webs. For example, concentrations of methylated Hg at mid-depths in the marine water column of the northern Canadian Arctic Archipelago were 79.8 ± 37.3 pg L(-1), whereas, in HB, they averaged only 38.3 ± 16.6 pg L(-1). We conclude that a longer food web and higher pelagic concentrations of methylated Hg available to initiate bioaccumulation in the BS resulted in higher concentrations of THg in polar bears from the SBS region compared to those inhabiting the western

  20. The Empirical Canadian High Arctic Ionospheric Model (E-CHAIM): NmF2 and hmF2 specification

    NASA Astrophysics Data System (ADS)

    Themens, David; Thayyil Jayachandran, P.

    2017-04-01

    It is well known that the International Reference Ionosphere (IRI) suffers reduced accuracy in its representation of monthly median ionospheric electron density at high latitudes (Themens et al. 2014, Themens et al. 2016). These inaccuracies are believed to stem from a historical lack of data from these regions. Now, roughly thirty and forty years after the development of the original URSI and CCIR foF2 maps, respectively, there exists a much larger dataset of high latitude observations of ionospheric electron density. These new measurements come in the form of new ionosonde deployments, such as those of the Canadian High Arctic Ionospheric Network, the CHAMP, GRACE, and COSMIC radio occultation missions, and the construction of the Poker Flat, Resolute, and EISCAT Incoherent Scatter Radar systems. These new datasets afford an opportunity to revise the IRI's representation of the high latitude ionosphere. For this purpose, we here introduce the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM), which incorporates all of the above datasets, as well as the older observation records, into a new climatological representation of the high latitude ionosphere. In this presentation, we introduce the NmF2 and hmF2 portions of the model, focusing on both climatological and storm-time representations, and present a validation of the new model with respect to ionosonde observations from four high latitude stations. A comparison with respect to IRI performance is also presented, where we see improvements by up to 70% in the representation of peak electron density through using the new E-CHAIM model. In terms of RMS errors, the E-CHAIM model is shown to represent a near-universal improvement over the IRI, sometimes by more than 1 MHz in foF2. For peak height, the E-CHAIM model demonstrates overall RMS errors of 13km at each test site compared to values of 18-35km for the IRI, depending on location. Themens, D.R., P. T. Jayachandran, et al. (2014). J. Geophys. Res. Space

  1. Long-term monitoring at multiple trophic levels suggests heterogeneity in responses to climate change in the Canadian Arctic tundra.

    PubMed

    Gauthier, Gilles; Bêty, Joël; Cadieux, Marie-Christine; Legagneux, Pierre; Doiron, Madeleine; Chevallier, Clément; Lai, Sandra; Tarroux, Arnaud; Berteaux, Dominique

    2013-08-19

    Arctic wildlife is often presented as being highly at risk in the face of current climate warming. We use the long-term (up to 24 years) monitoring records available on Bylot Island in the Canadian Arctic to examine temporal trends in population attributes of several terrestrial vertebrates and in primary production. Despite a warming trend (e.g. cumulative annual thawing degree-days increased by 37% and snow-melt date advanced by 4-7 days over a 23-year period), we found little evidence for changes in the phenology, abundance or productivity of several vertebrate species (snow goose, foxes, lemmings, avian predators and one passerine). Only primary production showed a response to warming (annual above-ground biomass of wetland graminoids increased by 123% during this period). We nonetheless found evidence for potential mismatches between herbivores and their food plants in response to warming as snow geese adjusted their laying date by only 3.8 days on average for a change in snow-melt of 10 days, half of the corresponding adjustment shown by the timing of plant growth (7.1 days). We discuss several reasons (duration of time series, large annual variability, amplitude of observed climate change, nonlinear dynamic or constraints imposed by various rate of warming with latitude in migrants) to explain the lack of response by herbivores and predators to climate warming at our study site. We also show how length and intensity of monitoring could affect our ability to detect temporal trends and provide recommendations for future monitoring.

  2. Biological and physical processes influencing sea ice, under-ice algae, and dimethylsulfoniopropionate during spring in the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Galindo, V.; Levasseur, M.; Mundy, C. J.; Gosselin, M.; Tremblay, J.-É.; Scarratt, M.; Gratton, Y.; Papakiriakou, T.; Poulin, M.; Lizotte, M.

    2014-06-01

    This study presents temporal variations in concentrations of chlorophyll a (Chl a), particulate and dissolved dimethylsulfoniopropionate (DMSPp and DMSPd) in the sea ice and underlying water column in the Canadian Arctic Archipelago during the spring of 2010 and 2011. During both years, bottom ice Chl a, DMSPp and DMSPd concentrations were high (up to 1328 µg L-1, 15,082 nmol L-1, and 6110 nmol L-1, respectively) in May and decreased thereafter. The release of bottom ice algae and DMSPp in the water column was gradual in 2010 and rapid (8 days) in 2011. Bottom brine drainage during the presnowmelt period in 2010 and a rapid loss of the snow cover in 2011 coinciding with rain events explain most of the difference between the 2 years. During both years, less than 13% of the DMSPd lost from the ice was detected in the water column, suggesting a rapid microbial consumption. An under-ice diatom bloom developed in both years. In 2010, the bloom was dominated by centric diatoms while in 2011 pennates dominated, likely reflecting seeding by ice algae following the faster snowmelt progression induced by rainfall events in 2011. Both under-ice blooms were associated with high DMSPp concentrations (up to 185 nmol L-1), but pennate diatoms showed DMSPp/Chl a ratios twice higher than centrics. These results highlight the key role of snowmelt and precipitation on the temporal pattern of ice-DMSP release to the water column and on the timing, taxonomic composition, and DMSP content of phytoplankton under-ice blooms in the Arctic.

  3. Stable Isotope Probing Analysis of the Diversity and Activity of Methanotrophic Bacteria in Soils from the Canadian High Arctic

    PubMed Central

    Martineau, Christine; Whyte, Lyle G.; Greer, Charles W.

    2010-01-01

    The melting of permafrost and its potential impact on CH4 emissions are major concerns in the context of global warming. Methanotrophic bacteria have the capacity to mitigate CH4 emissions from melting permafrost. Here, we used quantitative PCR (qPCR), stable isotope probing (SIP) of DNA, denaturing gradient gel electrophoresis (DGGE) fingerprinting, and sequencing of the 16S rRNA and pmoA genes to study the activity and diversity of methanotrophic bacteria in active-layer soils from Ellesmere Island in the Canadian high Arctic. Results showed that most of the soils had the capacity to oxidize CH4 at 4°C and at room temperature (RT), but the oxidation rates were greater at RT than at 4°C and were significantly enhanced by nutrient amendment. The DGGE banding patterns associated with active methanotrophic bacterial populations were also different depending on the temperature of incubation and the addition of nutrients. Sequencing of the 16S rRNA and pmoA genes indicated a low diversity of the active methanotrophic bacteria, with all methanotroph 16S rRNA and pmoA gene sequences being related to type I methanotrophs from Methylobacter and Methylosarcina. The dominance of type I methanotrophs over type II methanotrophs in the native soil samples was confirmed by qPCR of the 16S rRNA gene with primers specific for these two groups of bacteria. The 16S rRNA and pmoA gene sequences related to those of Methylobacter tundripaludum were found in all soils, regardless of the incubation conditions, and they might therefore play a role in CH4 degradation in situ. This work is providing new information supporting the potential importance of Methylobacter spp. in Arctic soils found in previous studies and contributes to the limited body of knowledge on methanotrophic activity and diversity in this extreme environment. PMID:20622133

  4. Evidence of recent changes in the ice regime of lakes in the Canadian High Arctic from spaceborne satellite observations

    NASA Astrophysics Data System (ADS)

    Surdu, C. M.; Duguay, C. R.; Fernández Prieto, D.

    2015-11-01

    Arctic lakes, through their ice cover phenology, are a key indicator of climatic changes that the high-latitude environment is experiencing. In the case of lakes in the Canadian Arctic Archipelago (CAA), many of which are ice covered more than ten months per year, warmer temperatures could result in ice regime shifts. Within the dominant polar-desert environment, small local warmer areas have been identified. These relatively small regions - polar oases - with longer growing seasons, greater biological production and diversity, are confined from the surrounding barren polar desert. The ice regimes of 11 lakes located in both polar-desert and polar-oasis environments, with surface areas between 4 and 542 km2, many of unknown bathymetry, were documented. In order to investigate the response of ice cover of lakes in the CAA to climate conditions during recent years, a 15-year time series (1997-2011) of RADARSAT-1/2 ScanSAR Wide Swath, ASAR Wide Swath and Landsat acquisitions were analysed. Results show that melt onset (MO) occurred earlier for all observed lakes. With the exception of Lower Murray Lake, all lakes experienced earlier summer-ice minimum and water-clear-of-ice dates (WCI), with greater changes being observed for polar-oasis lakes (9-24 days earlier WCI dates for lakes located in polar oases and 2-20 days earlier WCI dates for polar-desert lakes). Additionally, results suggest that some lakes may be transitioning from a perennial/multiyear to a seasonal ice regime, with only a few lakes maintaining a multiyear ice cover on occasional years. Aside Lake Hazen and Murray Lakes that preserved their ice cover during the summer of 2009, no residual ice was observed on any of the other lakes from 2007 to 2011.

  5. Evidence of recent changes in the ice regime of lakes in the Canadian High Arctic from spaceborne satellite observations

    NASA Astrophysics Data System (ADS)

    Surdu, Cristina M.; Duguay, Claude R.; Fernández Prieto, Diego

    2016-05-01

    Arctic lakes, through their ice cover phenology, are a key indicator of climatic changes that the high-latitude environment is experiencing. In the case of lakes in the Canadian Arctic Archipelago (CAA), many of which are ice covered more than 10 months per year, warmer temperatures could result in ice regime shifts. Within the dominant polar-desert environment, small local warmer areas have been identified. These relatively small regions - polar oases - with longer growing seasons and greater biological productivity and diversity are secluded from the surrounding barren polar desert. The ice regimes of 11 lakes located in both polar-desert and polar-oasis environments, with surface areas between 4 and 542 km2, many of unknown bathymetry, were documented. In order to investigate the response of ice cover of lakes in the CAA to climate conditions during recent years, a 15-year time series (1997-2011) of RADARSAT-1/2 ScanSAR Wide Swath, ASAR Wide Swath, and Landsat acquisitions were analyzed. Results show that melt onset occurred earlier for all observed lakes. With the exception of Lower Murray Lake, all lakes experienced earlier summer ice minimum and water-clear-of-ice (WCI) dates, with greater changes being observed for polar-oasis lakes (9-24 days earlier WCI dates for lakes located in polar oases and 2-20 days earlier WCI dates for polar-desert lakes). Additionally, results suggest that some lakes may be transitioning from a perennial/multiyear to a seasonal ice regime, with only a few lakes maintaining a multiyear ice cover on occasional years. Aside Lake Hazen and Murray Lakes, which preserved their ice cover during the summer of 2009, no residual ice was observed on any of the other lakes from 2007 to 2011.

  6. Long-term monitoring at multiple trophic levels suggests heterogeneity in responses to climate change in the Canadian Arctic tundra

    PubMed Central

    Gauthier, Gilles; Bêty, Joël; Cadieux, Marie-Christine; Legagneux, Pierre; Doiron, Madeleine; Chevallier, Clément; Lai, Sandra; Tarroux, Arnaud; Berteaux, Dominique

    2013-01-01

    Arctic wildlife is often presented as being highly at risk in the face of current climate warming. We use the long-term (up to 24 years) monitoring records available on Bylot Island in the Canadian Arctic to examine temporal trends in population attributes of several terrestrial vertebrates and in primary production. Despite a warming trend (e.g. cumulative annual thawing degree-days increased by 37% and snow-melt date advanced by 4–7 days over a 23-year period), we found little evidence for changes in the phenology, abundance or productivity of several vertebrate species (snow goose, foxes, lemmings, avian predators and one passerine). Only primary production showed a response to warming (annual above-ground biomass of wetland graminoids increased by 123% during this period). We nonetheless found evidence for potential mismatches between herbivores and their food plants in response to warming as snow geese adjusted their laying date by only 3.8 days on average for a change in snow-melt of 10 days, half of the corresponding adjustment shown by the timing of plant growth (7.1 days). We discuss several reasons (duration of time series, large annual variability, amplitude of observed climate change, nonlinear dynamic or constraints imposed by various rate of warming with latitude in migrants) to explain the lack of response by herbivores and predators to climate warming at our study site. We also show how length and intensity of monitoring could affect our ability to detect temporal trends and provide recommendations for future monitoring. PMID:23836788

  7. Mercaptan removal rate exceeds 99% at Canadian gas plant

    SciTech Connect

    Judd, B. )

    1993-08-16

    Installation of a Selexol solvent unit at Pembina Resources Ltd.'s Diamond Valley gas plant has been effective in polishing mercaptans and other sulfur-bearing compounds from a variable gas stream. The actual removal rate exceeds 99%, and an absolute treated gas target of < 100 ppm total sulfur is maintained. In addition, hydrocarbon pick up is restricted sufficiently so that slugs of hydrocarbon are not carried through the system to destabilize incineration of the mercaptans. The paper discusses start-up problems, the gas treating process, mercaptans in the feed gas, the solvent unit, and its operation.

  8. Application of global datasets for hydrological modelling of a remote, snowmelt driven catchment in the Canadian Sub-Arctic

    NASA Astrophysics Data System (ADS)

    Casson, David; Werner, Micha; Weerts, Albrecht; Schellekens, Jaap; Solomatine, Dimitri

    2017-04-01

    Hydrological modelling in the Canadian Sub-Arctic is hindered by the limited spatial and temporal coverage of local meteorological data. Local watershed modelling often relies on data from a sparse network of meteorological stations with a rough density of 3 active stations per 100,000 km2. Global datasets hold great promise for application due to more comprehensive spatial and extended temporal coverage. A key objective of this study is to demonstrate the application of global datasets and data assimilation techniques for hydrological modelling of a data sparse, Sub-Arctic watershed. Application of available datasets and modelling techniques is currently limited in practice due to a lack of local capacity and understanding of available tools. Due to the importance of snow processes in the region, this study also aims to evaluate the performance of global SWE products for snowpack modelling. The Snare Watershed is a 13,300 km2 snowmelt driven sub-basin of the Mackenzie River Basin, Northwest Territories, Canada. The Snare watershed is data sparse in terms of meteorological data, but is well gauged with consistent discharge records since the late 1970s. End of winter snowpack surveys have been conducted every year from 1978-present. The application of global re-analysis datasets from the EU FP7 eartH2Observe project are investigated in this study. Precipitation data are taken from Multi-Source Weighted-Ensemble Precipitation (MSWEP) and temperature data from Watch Forcing Data applied to European Reanalysis (ERA)-Interim data (WFDEI). GlobSnow-2 is a global Snow Water Equivalent (SWE) measurement product funded by the European Space Agency (ESA) and is also evaluated over the local watershed. Downscaled precipitation, temperature and potential evaporation datasets are used as forcing data in a distributed version of the HBV model implemented in the WFLOW framework. Results demonstrate the successful application of global datasets in local watershed modelling, but

  9. Factors affecting biotic mercury concentrations and biomagnification through lake food webs in the Canadian high Arctic.

    PubMed

    Lescord, Gretchen L; Kidd, Karen A; Kirk, Jane L; O'Driscoll, Nelson J; Wang, Xiaowa; Muir, Derek C G

    2015-03-15

    In temperate regions of Canada, mercury (Hg) concentrations in biota and the magnitude of Hg biomagnification through food webs vary between neighboring lakes and are related to water chemistry variables and physical lake features. However, few studies have examined factors affecting the variable Hg concentrations in landlocked Arctic char (Salvelinus alpinus) or the biomagnification of Hg through their food webs. We estimated the food web structure of six high Arctic lakes near Resolute Bay, Nunavut, Canada, using stable carbon (δ(13)C) and nitrogen (δ(15)N) isotopes and measured Hg (total Hg (THg) in char, the only fish species, and methylmercury (MeHg) in chironomids and zooplankton) concentrations in biota collected in 2010 and 2011. Across lakes, δ(13)C showed that benthic carbon (chironomids) was the dominant food source for char. Regression models of log Hg versus δ(15)N (of char and benthic invertebrates) showed positive and significant slopes, indicting Hg biomagnification in all lakes, and higher slopes in some lakes than others. However, no principal components (PC) generated using all water chemistry data and physical characteristics of the lakes predicted the different slopes. The PC dominated by aqueous ions was a negative predictor of MeHg concentrations in chironomids, suggesting that water chemistry affects Hg bioavailability and MeHg concentrations in these lower-trophic-level organisms. Furthermore, regression intercepts were predicted by the PCs dominated by catchment area, aqueous ions, and MeHg. Weaker relationships were also found between THg in small char or MeHg in pelagic invertebrates and the PCs dominated by catchment area, and aqueous nitrate and MeHg. Results from these high Arctic lakes suggest that Hg biomagnification differs between systems and that their physical and chemical characteristics affect Hg concentrations in lower-trophic-level biota. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Inorganic carbon dynamics of melt pond-covered first year sea ice in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Geilfus, N.-X.; Galley, R. J.; Crabeck, O.; Papakyriakou, T.; Landy, J.; Tison, J.-L.; Rysgaard, S.

    2014-05-01

    Melt pond formation is a common feature of the spring and summer Arctic sea ice. However, the role of the melt ponds formation and the impact of the sea ice melt on both the direction and size of CO2 flux between air and sea is still unknown. Here we describe the CO2-carbonate chemistry of melting sea ice, melt ponds and the underlying seawater associated with measurement of CO2 fluxes across first year landfast sea ice in the Resolute Passage, Nunavut, in June 2012. Early in the melt season, the increase of the ice temperature and the subsequent decrease of the bulk ice salinity promote a strong decrease of the total alkalinity (TA), total dissolved inorganic carbon (TCO2) and partial pressure of CO2 (pCO2) within the bulk sea ice and the brine. Later on, melt pond formation affects both the bulk sea ice and the brine system. As melt ponds are formed from melted snow the in situ melt pond pCO2 is low (36 μatm). The percolation of this low pCO2 melt water into the sea ice matrix dilutes the brine resulting in a strong decrease of the in situ brine pCO2 (to 20 μatm). As melt ponds reach equilibrium with the atmosphere, their in situ pCO2 increase (up to 380 μatm) and the percolation of this high concentration pCO2 melt water increase the in situ brine pCO2 within the sea ice matrix. The low in situ pCO2 observed in brine and melt ponds results in CO2 fluxes of -0.04 to -5.4 mmol m-2 d-1. As melt ponds reach equilibrium with the atmosphere, the uptake becomes less significant. However, since melt ponds are continuously supplied by melt water their in situ pCO2 still remains low, promoting a continuous but moderate uptake of CO2 (~ -1mmol m-2 d-1). The potential uptake of atmospheric CO2 by melting sea ice during the Arctic summer has been estimated from 7 to 16 Tg of C ignoring the role of melt ponds. This additional uptake of CO2 associated to Arctic sea ice needs to be further explored and considered in the estimation of the Arctic Ocean's overall CO2 budget.

  11. Last Decade of Changes in Ground Temperature and Active Layer Thickness in the High Canadian Arctic and in Barrow

    NASA Astrophysics Data System (ADS)

    Romanovsky, V. E.; Cable, W.; Walker, D. A.; Yoshikawa, K.; Marchenko, S. S.

    2013-12-01

    The impact of climate warming on permafrost and the potential of climate feedbacks resulting from permafrost thawing have recently received a great deal of attention. Most of the permafrost observatories in the Northern Hemisphere show substantial warming of permafrost since circa 1980-1990. The magnitude of warming has varied with location, but was typically from 0.5 to 2°C. Permafrost is already thawing within the southern part of the permafrost domain. However, recent observations documented propagation of this process northward into the continuous permafrost zone. The close proximity of the exceptionally icy soil horizons to the ground surface, which is typical for the arctic tundra biome, makes tundra surfaces extremely sensitive to the natural and human-made changes that may resulted in development of processes such as thermokarst, thermal erosion, and retrogressive thaw slumps that strongly affect the stability of ecosystems and infrastructure. In 2003-2005, three Ecological Permafrost Observatories where established in the High Canadian Arctic (Green Cabin on the Banks Island, Mould Bay on the Prince Patrick Island, and Isachsen on the Ellef Ringnes Island) as a part of the University of Alaska Fairbanks NSF funded Biocomplexity Project. These observatories represent the northern part of the North American Arctic Transect (NAAT) established as a result of this project. The climatic and ground temperature data collected at these observatories show a general warming trend similar to what has been observed at the other locations in the North American Arctic. An important result of this resent warming is a significant increase in the active layer thickness (ALT) during the last decade. For example, ALT at the Isachsen observatory increased from 0.4-0.42 m in 2005 to 0.54 m in 2012. The maximum ALT of 0.58 m was recorded in 2008. In a shallow excavation across an ice wedge at the Isachsen site, we estimated that the top of the ice wedge ice was located at 42

  12. Particle-associated extracellular enzyme activity and bacterial community composition across the Canadian Arctic Ocean.

    PubMed

    Kellogg, Colleen T E; Deming, Jody W

    2014-08-01

    Microbial enzymatic hydrolysis of marine-derived particulate organic carbon (POC) can be a dominant mechanism for attenuating carbon flux in cold Arctic waters during spring and summer. Whether this mechanism depends on composition of associated microbial communities and extends into other seasons is not known. Bacterial community composition (BCC) and extracellular enzyme activity (EEA, for leucine aminopeptidases, glucosidases and chitobiases) were measured on small suspended particles and potentially sinking aggregates collected during fall from waters of the biologically productive North Water and river-impacted Beaufort Sea. Although other environmental variables appeared influential, both BCC and EEA varied along a marine productivity gradient in the two regions. Aggregates harbored the most distinctive bacterial communities, with a small number of taxa driving differences between particle-size classes (1.0-60 and > 60 μm) and free-living bacteria (0.2-1.0 μm). Significant relationships between patterns in particle-associated BCC and EEA suggest strong links between these two variables. Calculations indicated that up to 80% of POC in the euphotic zone of the North Water, and 20% in the Beaufort Sea, may be hydrolyzed enzymatically, underscoring the importance of this mechanism in attenuating carbon fluxes in Arctic waters even as winter approaches. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  13. Bioremediation of weathered petroleum hydrocarbon soil contamination in the Canadian High Arctic: laboratory and field studies.

    PubMed

    Sanscartier, David; Laing, Tamsin; Reimer, Ken; Zeeb, Barbara

    2009-11-01

    The bioremediation of weathered medium- to high-molecular weight petroleum hydrocarbons (HCs) in the High Arctic was investigated. The polar desert climate, contaminant characteristics, and logistical constraints can make bioremediation of persistent HCs in the High Arctic challenging. Landfarming (0.3 m(3) plots) was tested in the field for three consecutive years with plots receiving very little maintenance. Application of surfactant and fertilizers, and passive warming using a greenhouse were investigated. The field study was complemented by a laboratory experiment to better understand HC removal mechanisms and limiting factors affecting bioremediation on site. Significant reduction of total petroleum HCs (TPH) was observed in both experiments. Preferential removal of compounds nC16 occurred, whereas in the field, TPH reduction was mainly limited to removal of compounds nC16 was observed in the fertilized field plots only. The greenhouse increased average soil temperatures and extended the treatment season but did not enhance bioremediation. Findings suggest that temperature and low moisture content affected biodegradation of HCs in the field. Little volatilization was measured in the laboratory, but this process may have been predominant in the field. Low-maintenance landfarming may be best suited for remediation of HCs compounds

  14. Managing scientific diving operations in a remote location: the Canadian high Arctic.

    PubMed

    Sayer, Martin D J; Küpper, Frithjof C; van West, Pieter; Wilson, Colin M; Brown, Hugh; Azzopardi, Elaine

    2013-12-01

    Global climate change is expected to alter the Arctic bioregion markedly in coming decades. As a result, monitoring of the expected and actual changes has assumed high scientific significance. Many marine science objectives are best supported with the use of scientific diving techniques. Some important keystone environments are located in extremely remote locations where land-based expeditions offer high flexibility and cost-effectiveness over ship-based operations. However, the extreme remoteness of some of these locations, coupled with complex and unreliable land, sea and air communications, means that there is rarely quick access (< 48 h) to any specialized diving medical intervention or recompression. In 2009, a land based expedition to the north end of Baffin Island was undertaken with the specific aim of establishing an inventory of the diversity of seaweeds and their pathogens that was broadly representative of a high Arctic marine environment. This account highlights some of the logistical considerations taken on that expedition; specifically it outlines the non-recompression treatment pathway that would have been adopted in the event of a diver suffering decompression illness.

  15. Achievements and challenges on policies for allied health professionals who use telehealth in the Canadian Arctic.

    PubMed

    Hailey, D; Foerster, V; Nakagawa, B; Wapshall, T M; Murtagh, J A; Smitten, J; Steblecki, J A; Wong, G

    2005-01-01

    We formulated policies and procedures for allied health professionals (AHPs) who provide services using telehealth in Nunavut, Canada's newest Arctic territory. These are a supplement to the clinical policies and procedures already established for Nunavut physicians and nurses. The services were in the areas of audiology, dietetics/nutrition, midwifery, occupational therapy, ophthalmic services, pharmacy, physiotherapy, psychology, respiratory therapy, social work and speech therapy. Documents specific to each of the services were developed, drawing on information from Government of Nunavut data, Nunavut healthcare providers and links made through the Internet. Topics included the scope and limitations of telehealth services, staff responsibilities, training and reporting, professional standards and cultural considerations. We also considered generic policies covering common issues such as jurisdiction, licensing and liability. The policies and procedures for AHPs will enhance and expand the successes already achieved with telehealth in Nunavut. The challenges are to balance the preferred approaches to service provision with the realities of health care and communications in an Arctic setting.

  16. Isotopic analyses (/sup 18/O, /sup 13/C, /sup 14/C) of two meromictic lakes in the Canadian Arctic Archipelago

    SciTech Connect

    Page, P.; Ouellet, M.; Hillaire-Marcel, C.; Dickman, M.

    1984-05-01

    Meromictic Lakes Garrow and Sophia in the Canadian Arctic Archipelago were sampled to establish the origin and age of their water by isotopic studies. /sup 18/O values reflect the permanent stratification of the water in both lakes. The mixolimnia contain waters with an isotopic signal between -13.16 and -21.98%, coherent with the values for precipitation in these high latitudes. In the chemoclines, the delta/sup 18/O values increase to -10% concomitantly with a rise in chloride content to 42 g.liter/sup -1/. In the monimolimnia, hypersaline waters (up to 2.5 times the salinity of seawater) show negative delta/sup 18/O values (ca. -.08%). These waters result from brine production during permafrost growth in the watershed, according to a Rayleigh process. /sup 14/C dating of total inorganic carbon in the Lake Garrow monimolimnion gave an age of 2580 +/- 260 years BP. In Lake Sophia, the deep waters exhibit recent /sup 14/C activity that suggests recent infiltration of seawater into the lake basin.

  17. Isotopic analyses (/sup 18/O, /sup 13/C, /sup 14/C) of two meromictic lakes in the Canadian Arctic Archipelago

    SciTech Connect

    Page, P.; Ouellet, M.; Hillaire-Marcel, C.; Dickman, M.

    1984-05-01

    Meromictic Lakes Garrow and Sophia in the Canadian Arctic Archipelago were sampled to establish the origin and age of their waters by isotopic studies. The sigma/sub SMOW//sup 18/O values reflect the permanent stratification of the waters in both lakes. The mixolimnia contain waters with an isotopic signal between -13.16 and -2.198%, coherent with the values of precipitation in these high latitudes. The short residence time of the water in this layer makes it possible to record episodic variations of the freshwater inputs to the lakes. In the chemoclines, the sigma/sup 18/O values increase to -10% concomitantly with a rise in chloride content to 42 g liter/sup -1/. This corresponds to a conservative mixing of surficial and deep waters. In the monimolimnia, hypersaline waters from brine production during permafrost growth in the watershed, according to a Rayleigh process. The brines drained toward the deepest part of each lake, after postglacial uplift, and became isolated. /sup 14/C dating of total inorganic carbon in the Lake Garrow monimolimnion gave an age of 2580 +/- 260 years B.P. In Lake Sophia, the deep waters exhibit recent /sup 14/C activity (121.4% modern carbon) that suggests recent infiltration of seawater into the lake basin.

  18. Insights into antimicrobial resistance among long distance migratory East Canadian High Arctic light-bellied Brent geese (Branta bernicla hrota).

    PubMed

    Agnew, Austin; Wang, Juan; Fanning, Séamus; Bearhop, Stuart; McMahon, Barry J

    2015-01-01

    Antimicrobial resistance (AMR) is the most significant threat to global public health and ascertaining the role wild birds play in the epidemiology of resistance is critically important. This study investigated the prevalence of AMR Gram-negative bacteria among long-distance migratory East Canadian High Arctic (ECHA) light-bellied Brent geese found wintering on the east coast of Ireland. In this study a number of bacterial species were isolated from cloacal swabs taken from ECHA light-bellied Brent geese. Nucleotide sequence analysis identified five species of Gram-negative bacteria; the dominant isolated species were Pantoea spp. (n = 5) followed by Buttiauxella agrestis (n = 2). Antimicrobial susceptibility disk diffusion results identified four of the Pantoea spp. strains, and one of the Buttiauxella agrestis strains resistant to amoxicillin-clavulanic acid. To our knowledge this is the first record of AMR bacteria isolated from long distance migratory ECHA light-bellied Brent geese. This indicates that this species may act as reservoirs and potential disseminators of resistance genes into remote natural ecosystems across their migratory range. This population of geese frequently forage (and defecate) on public amenity areas during the winter months presenting a potential human health risk.

  19. A structural fabric defined by topographic lineaments: Correlation with Tertiary deformation of Ellesmere and Axel Heiberg Islands, Canadian Arctic

    NASA Technical Reports Server (NTRS)

    Oakey, Gordon

    1994-01-01

    Digital topographic contours from four 1:250000 scale maps have been gridded to produce a digital elevation model for part of Ellesmere and Axel Heiberg islands in the Canadian Arctic Islands. Gradient calculations were used to define both east and west dipping slopes defining a pattern of lineaments that have been compared with mapped geological structures. In ice-covered areas, where geological mapping was not possible, well-defined topographic lineaments have been identified and are correlated to extensions of major structural features. The northeast-southwest patterns of both topographic lineaments and mapped structures are strongly unimodal and support a single compressive event oriented at 67 deg west of north. This orientation is coincidental with the convergence direction calculated from the kinematic poles of rotation for Greenland relative to North America between 56 and 35 Ma. A minor secondary peak at 70 east of north is observed for thrust and normal fault solutions and is not directly related to the predicted convergence direction. Whether this represents a unique phase of deformation or is a subcomponent of a single event is not known. The agreement of structural components, lineament orientations, and convergence direction suggests an overwhelming over print of Eurekan deformation on any preexisting structural fabric. This study confirms, for the first time, an excellent compatibility between geological and geophysical constraints for the timing and geometry of the Eurekan orogeny.

  20. Isolation and characterization of Brachyspira spp. including "Brachyspira hampsonii" from lesser snow geese (Chen caerulescens caerulescens) in the Canadian Arctic.

    PubMed

    Rubin, Joseph E; Harms, N Jane; Fernando, Champika; Soos, Catherine; Detmer, Susan E; Harding, John C S; Hill, Janet E

    2013-11-01

    Brachyspira is associated with diarrhea and colitis in pigs, and control of these pathogens is complicated by their complex ecology. Identification of wildlife reservoirs of Brachyspira requires the discrimination of colonized animals and those simply contaminated through environmental exposure. Lesser snow geese (Chen caerulescens caerulescens) were sampled in the Canadian arctic during the summer of 2011, and cloacal swabs were cultured on selective media. Brachyspira isolates were obtained from 15/170 (8.8 %) samples, and 12/15 isolates were similar to isolates previously recovered from pigs, including "Brachyspira hampsonii", a recently characterized species associated with dysentery-like disease in pigs in North America. A pilot inoculation study with one strongly β-hemolytic B. hampsonii isolate resulted in fecal shedding of the isolate by inoculated pigs for up to 14 days post-inoculation, but no severe clinical disease. Results of this study indicate that lesser snow geese can be colonized by Brachyspira strains that can also colonize pigs. Millions of lesser snow geese (C. caerulescens caerulescens) travel through the major pork-producing areas of Canada and the USA during their annual migration, making them a potential factor in the continental distribution of these bacteria.

  1. Microbial diversity and activity through a permafrost/ground ice core profile from the Canadian high Arctic.

    PubMed

    Steven, Blaire; Pollard, Wayne H; Greer, Charles W; Whyte, Lyle G

    2008-12-01

    Culture-dependent and culture-independent methods were used in an investigation of the microbial diversity in a permafrost/massive ground ice core from the Canadian high Arctic. Denaturing gradient gel electrophoresis as well as Bacteria and Archaea 16S rRNA gene clone libraries showed differences in the composition of the microbial communities in the distinct core horizons. Microbial diversity was similar in the active layer (surface) soil, permafrost table and permafrost horizons while the ground ice microbial community showed low diversity. Bacteria and Archaea sequences related to the Actinobacteria (54%) and Crenarchaeota (100%) respectively were predominant in the active layer while the majority of sequences in the permafrost were related to the Proteobacteria (57%) and Euryarchaeota (76%). The most abundant phyla in the ground ice clone libraries were the Firmicutes (59%) and Crenarchaeota (82%). Isolates from the permafrost were both less abundant and diverse than in the active layer soil, while no culturable cells were recovered from the ground ice. Mineralization of [1-(14)C] acetic acid and [2-(14)C] glucose was used to detect microbial activity in the different horizons in the core. Mineralization was detected at near ambient permafrost temperatures (-15 degrees C), indicating that permafrost may harbour an active microbial population, while the low microbial diversity, abundance and activity in ground ice suggests a less hospitable microbial habitat.

  2. Submarine debris flows and continental slople evolution in front of Quaternary ice sheets, Baffin Bay, Canadian Arctic

    SciTech Connect

    Hiscott, R.N.; Aksu, A.E. )

    1994-03-01

    Baffin Bay is a semi-enclosed extension of the Labrador Sea in the Canadian Arctic. The upper Pliocene and Quaternary successions beneath the continental slope contain important slumps and debris-flow deposits. New high-resolution single-channel seismic data have been acquired from a 500 to 600-m-deep transverse trough that indents that shelf in an area where glacial outflow was focused during the Pliocene and Pleistocene. Major shelf-edge progradation occurred both inside and on the flanks of the transverse trough. In the lower slope, several large debris flows carried proglacial deposits into the deep basin. The largest of these debris flows dramatically reshaped the sea floor by reducing bottom slopes both by proximal erosion and distal thickening of the debris-flow deposit. Subsequently, the lower slope was starved of terrigenous input, and the upper slope was steepened by accumulation of basinward thinning wedges of mass flow deposits. The processes of emplacement of large debris flows, slope reshaping, and out-of-phase accumulation identified in upper and lower slope areas of Baffin Bay are relevant to the interpretation of other line-source margins affected by major sea level falls or changes in sediment influx, including siliciclastic slope aprons and carbonate platform margins. On fans, muddy debris flows provide both a potential seal for hydrocarbons generated after burial and a potentially important mass of organic-rich mudstones that may act as source rocks in the subsurface. 32 refs., 14 figs., 1 tab.

  3. A structural fabric defined by topographic lineaments: Correlation with Tertiary deformation of Ellesmere and Axel Heiberg Islands, Canadian Arctic

    NASA Technical Reports Server (NTRS)

    Oakey, Gordon

    1994-01-01

    Digital topographic contours from four 1:250000 scale maps have been gridded to produce a digital elevation model for part of Ellesmere and Axel Heiberg islands in the Canadian Arctic Islands. Gradient calculations were used to define both east and west dipping slopes defining a pattern of lineaments that have been compared with mapped geological structures. In ice-covered areas, where geological mapping was not possible, well-defined topographic lineaments have been identified and are correlated to extensions of major structural features. The northeast-southwest patterns of both topographic lineaments and mapped structures are strongly unimodal and support a single compressive event oriented at 67 deg west of north. This orientation is coincidental with the convergence direction calculated from the kinematic poles of rotation for Greenland relative to North America between 56 and 35 Ma. A minor secondary peak at 70 east of north is observed for thrust and normal fault solutions and is not directly related to the predicted convergence direction. Whether this represents a unique phase of deformation or is a subcomponent of a single event is not known. The agreement of structural components, lineament orientations, and convergence direction suggests an overwhelming over print of Eurekan deformation on any preexisting structural fabric. This study confirms, for the first time, an excellent compatibility between geological and geophysical constraints for the timing and geometry of the Eurekan orogeny.

  4. Methane-cycling communities in a permafrost-affected soil on Herschel Island, Western Canadian Arctic: active layer profiling of mcrA and pmoA genes.

    PubMed

    Barbier, Béatrice A; Dziduch, Isabel; Liebner, Susanne; Ganzert, Lars; Lantuit, Hugues; Pollard, Wayne; Wagner, Dirk

    2012-11-01

    In Arctic wet tundra, microbial controls on organic matter decomposition are likely to be altered as a result of climatic disruption. Here, we present a study on the activity, diversity and vertical distribution of methane-cycling microbial communities in the active layer of wet polygonal tundra on Herschel Island. We recorded potential methane production rates from 5 to 40 nmol h(-1) g(-1) wet soil at 10 °C and significantly higher methane oxidation rates reaching values of 6-10 μmol h(-1) g(-1) wet soil. Terminal restriction fragment length polymorphism (T-RFLP) and cloning analyses of mcrA and pmoA genes demonstrated that both communities were stratified along the active layer vertical profile. Similar to other wet Arctic tundra, the methanogenic community hosted hydrogenotrophic (Methanobacterium) as well as acetoclastic (Methanosarcina and Methanosaeta) members. A pronounced shift toward a dominance of acetoclastic methanogens was observed in deeper soil layers. In contrast to related circum-Arctic studies, the methane-oxidizing (methanotrophic) community on Herschel Island was dominated by members of the type II group (Methylocystis, Methylosinus, and a cluster related to Methylocapsa). The present study represents the first on methane-cycling communities in the Canadian Western Arctic, thus advancing our understanding of these communities in a changing Arctic.

  5. Ship emissions measurement in the Arctic by plume intercepts of the Canadian Coast Guard icebreaker Amundsen from the Polar 6 aircraft platform

    NASA Astrophysics Data System (ADS)

    Aliabadi, Amir A.; Thomas, Jennie L.; Herber, Andreas B.; Staebler, Ralf M.; Leaitch, W. Richard; Schulz, Hannes; Law, Kathy S.; Marelle, Louis; Burkart, Julia; Willis, Megan D.; Bozem, Heiko; Hoor, Peter M.; Köllner, Franziska; Schneider, Johannes; Levasseur, Maurice; Abbatt, Jonathan P. D.

    2016-06-01

    Decreasing sea ice and increasing marine navigability in northern latitudes have changed Arctic ship traffic patterns in recent years and are predicted to increase annual ship traffic in the Arctic in the future. Development of effective regulations to manage environmental impacts of shipping requires an understanding of ship emissions and atmospheric processing in the Arctic environment. As part of the summer 2014 NETCARE (Network on Climate and Aerosols) campaign, the plume dispersion and gas and particle emission factors of effluents originating from the Canadian Coast Guard icebreaker Amundsen operating near Resolute Bay, NU, Canada, were investigated. The Amundsen burned distillate fuel with 1.5 wt % sulfur. Emissions were studied via plume intercepts using the Polar 6 aircraft measurements, an analytical plume dispersion model, and using the FLEXPART-WRF Lagrangian particle dispersion model. The first plume intercept by the research aircraft was carried out on 19 July 2014 during the operation of the Amundsen in the open water. The second and third plume intercepts were carried out on 20 and 21 July 2014 when the Amundsen had reached the ice edge and operated under ice-breaking conditions. Typical of Arctic marine navigation, the engine load was low compared to cruising conditions for all of the plume intercepts. The measured species included mixing ratios of CO2, NOx, CO, SO2, particle number concentration (CN), refractory black carbon (rBC), and cloud condensation nuclei (CCN). The results were compared to similar experimental studies in mid-latitudes. Plume expansion rates (γ) were calculated using the analytical model and found to be γ = 0.75 ± 0.81, 0.93 ± 0.37, and 1.19 ± 0.39 for plumes 1, 2, and 3, respectively. These rates were smaller than prior studies conducted at mid-latitudes, likely due to polar boundary layer dynamics, including reduced turbulent mixing compared to mid-latitudes. All emission factors were in agreement with prior

  6. Canadian offshore oil production solution gas utilization alternatives

    SciTech Connect

    Wagner, J.V.

    1999-07-01

    Oil and gas development in the Province of Newfoundland and Labrador is in its early stage and the offshore industry emphasis is almost exclusively on oil production. At the Hibernia field, the Gravity Base Structure (GBS) is installed and the first wells are in production. The Terra Nova project, based on a Floating Production Storage Offloading (FPSO) ship shaped concept, is in its engineering and construction stage and first oil is expected by late 2000. Several other projects, such as Husky's White Rose and Chevron's Hebron, have significant potential for future development in the same area. It is highly probably that these projects will employ the FPSO concept. It is also expected that the solution gas disposal issues of such second generation projects will be of more significance in their regulatory approval process and of such second generation projects will be of more significance in their regulatory approval process and the operators may be forced to look for alternatives to gas reinjection. Three gas utilization alternatives for a FPSO concept based project have been considered and evaluated in this paper: liquefied natural gas (LNG), compressed natural gas (CNG), and gas-to-liquids conversion (GTL). The evaluation and the relative ranking of these alternatives is based on a first pass screening type of study which considers the technical and economical merits of each alternative. Publicly available information and in-house data, compiled within Fluor Daniel's various offices, was used to establish the basic parameters.

  7. Influence of Arctic sea-ice and greenhouse gas concentration change on the West African Monsoon.

    NASA Astrophysics Data System (ADS)

    Monerie, Paul-Arthur; Oudar, Thomas; Sanchez-Gomez, Emilia; Terray, Laurent

    2016-04-01

    The Sahelian precipitation are projected to increase in the CNRM-CM5 coupled climate model due to a strengthening of the land-Sea temperature gradient, the increase in the North Atlantic temperature and the deepening of the Heat Low. Arctic Sea-Ice loss impacts the low-level atmospheric circulation through a decrease in the northward heat transport. Some authors have linked the sea-ice loss to a poleward shift of the InterTropical Convergence Zone. Within the CMIP5 models the effect of these mechanisms are not distinguishable and it is difficult to understand the effect of the Arctic sea-ice loss on the West African Monsoon so far. We performed several sensitivity experiments with the CNRM-CM5 coupled climate models by modifying the arctic sea-ice extent and/or the greenhouse gas concentration. We then investigated separately the impact of Arctic sea-ice loss and greenhouse gas concentration increases on the West African Monsoon. The increase in greenhouse gas explains the northward shift and the strengthening of the monsoon. Its effect is stronger with a sea-ice free Arctic that leads to an increase in North Atlantic temperature and in Sahelian precipitation at the end of the rainy season (September-October). We argue that the decrease in sea-ice extent, in the context of the global warming, may moistens the Sahel during the rainy season by changing the pressure, winds and moisture fluxes at low-level.

  8. Paleoclimatology of the Early Paleogene using Kimberlite-Hosted Mummified Wood from the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Hook, B. A.; Halfar, J.; Gedalof, Z.; Bollmann, J.; Schulze, D. J.

    2011-12-01

    Fifty-five million years ago, during the Paleocene-Eocene transition, average global temperatures were 4 - 7°C warmer than today and tropical forest ecosystems persisted in Arctic regions for millennia (ref. 1). Superimposed on this warmth were several hyperthermal periods of intense warming (10 - 12°C above modern-day average), such as the Paleocene-Eocene Thermal Maximum (PETM; 55.5 Ma), caused by an influx of isotopically-light carbon of unknown origin into the atmosphere (ref. 2). During this time, massive kimberlite eruptions buried forest fragments under pyroclastic debris. Evidence can be found in several diamondiferous kimberlite mines in the Northwest Territories of Canada, aged at 56.0 ±0.7 Ma (Diavik Mine) and 53.2 ±0.3 Ma (Ekati Mine) (ref. 3). Due to these unique burial conditions, the original woody material is intact (i.e. not petrified) allowing paleoclimatic analyses from wood growing before and after the PETM. Morelet Wavelet Analysis detected a significant 4 - 7 year periodicity in tree-ring width suggesting Cenozoic El Niño climate cycles were similar to those existing today, thus validating paleoclimatic models (ref. 4). In addition, evidence of wood-boring insect galleries within samples suggests the existence of a rich ecosystem above the Arctic Circle. Our multi-proxy study of δ13C, δ18O, and δD isotope ratios in α-cellulose at sub-annual scales will permit a better understanding of seasonal and yearly trends in Early Paleogene temperature and precipitation. It will also allow comparisons with studies of Eocene-aged wood (45 Ma) suggesting Arctic regions were 10 - 12°C warmer than modern-day temperatures, with relative humidity reaching 90 - 100% by the end of the growing season (refs. 5,6). 1. Zachos, J, M Pagani, L Sloan, E Thomas, and K Billups. 2001. Science 292(5517): 686 - 693. 2. Higgins, JA, and DP Schrag. 2006. Earth and Planetary Science Letters 245: 523-537. 3. Creaser, RA, H Grütter, J Carlson, and B Crawford. 2004

  9. The cost of lower respiratory tract infections hospital admissions in the Canadian Arctic

    PubMed Central

    Banerji, Anna; Panzov, Val; Robinson, Joan; Young, Michael; Ng, Kaspar; Mamdani, Muhammad

    2013-01-01

    Background Inuit infants who reside in the Nunavut (NU) regions of Arctic Canada have extremely high rates of lower respiratory tract infections (LRTIs) associated with significant health expenditures, but the costs in other regions of Arctic Canada have not been documented. Objective This prospective surveillance compares, across most of Arctic Canada, the rates and costs associated with LRTI admissions in infants less than 1 year of age, and the days of hospitalization and costs adjusted per live birth. Design This was a hospital-based surveillance of LRTI admissions of infants less than 1 year of age, residing in Northwest Territories (NT), the 3 regions of Nunavut (NU); [Kitikmeot (KT), Kivalliq (KQ) and Qikiqtani (QI)] and Nunavik (NK) from 1 January 2009 to 30 June 2010. Costs were obtained from the territorial or regional governments and hospitals, and included transportation, hospital stay, physician fees and accommodation costs. The rates of LRTI hospitalizations, days of hospitalization and associated costs were calculated per live birth in each of the 5 regions. Results There were 513 LRTI admissions during the study period. For NT, KT, KQ, QI and NK, the rates of LRTI hospitalization per 1000 live births were 38, 389, 230, 202 and 445, respectively. The total days of LRTI admission per live birth were 0.25, 3.3, 2.6, 1.7 and 3 for the above regions. The average cost per live birth for LRTI admission for these regions was $1,412, $22,375, $14,608, $8,254 and $10,333. The total cost for LRTI was $1,498,232 in NT, $15,662,968 in NU and $3,874,881 in NK. Medical transportation contributed to a significant proportion of the costs. Conclusion LRTI admission rates in NU and Nunavik are much higher than that in NT and remain among the highest rates globally. The costs of these admissions are exceptionally high due to the combination of very high rates of admission, very expensive medical evacuations and prolonged hospitalizations. Decreasing the rates of LRTI

  10. "mus co shee": Indigenous Plant Foods and Horticultural Imperialism in the Canadian Sub-Arctic.

    PubMed

    Soloway, Beverly

    2015-01-01

    The 17th-century arrival of the Hudson's Bay Company in Rupert's Land disrupted Mushkegowuk (Cree) hunter-gatherer society by replacing the collection of indigenous plant foods with a British planted-food model. Within a hundred years of British contact, new foodways relied upon hunting and gardening, bringing a loss in heritage plant food knowledge. Mushkegowuk living in the sub-arctic today have minimal knowledge of edible indigenous plants. Dependence on limited local gardening or imported grocery store vegetables has affected diet, nutrition, and cultural systems. In addition to exploring plant food gathering and gardening history in the Hudson Bay Lowlands, this paper demonstrates how re-discovering lost foodway knowledge can contribute to the health and well-being of those living in the far north.

  11. Metagenomic analysis of the bioremediation of diesel-contaminated Canadian high arctic soils.

    PubMed

    Yergeau, Etienne; Sanschagrin, Sylvie; Beaumier, Danielle; Greer, Charles W

    2012-01-01

    As human activity in the Arctic increases, so does the risk of hydrocarbon pollution events. On site bioremediation of contaminated soil is the only feasible clean up solution in these remote areas, but degradation rates vary widely between bioremediation treatments. Most previous studies have focused on the feasibility of on site clean-up and very little attention has been given to the microbial and functional communities involved and their ecology. Here, we ask the question: which microorganisms and functional genes are abundant and active during hydrocarbon degradation at cold temperature? To answer this question, we sequenced the soil metagenome of an ongoing bioremediation project in Alert, Canada through a time course. We also used reverse-transcriptase real-time PCR (RT-qPCR) to quantify the expression of several hydrocarbon-degrading genes. Pseudomonas species appeared as the most abundant organisms in Alert soils right after contamination with diesel and excavation (t = 0) and one month after the start of the bioremediation treatment (t = 1m), when degradation rates were at their highest, but decreased after one year (t = 1y), when residual soil hydrocarbons were almost depleted. This trend was also reflected in hydrocarbon degrading genes, which were mainly affiliated with Gammaproteobacteria at t = 0 and t = 1m and with Alphaproteobacteria and Actinobacteria at t = 1y. RT-qPCR assays confirmed that Pseudomonas and Rhodococcus species actively expressed hydrocarbon degradation genes in Arctic biopile soils. Taken together, these results indicated that biopile treatment leads to major shifts in soil microbial communities, favoring aerobic bacteria that can degrade hydrocarbons.

  12. Metagenomic Analysis of the Bioremediation of Diesel-Contaminated Canadian High Arctic Soils

    PubMed Central

    Yergeau, Etienne; Sanschagrin, Sylvie; Beaumier, Danielle; Greer, Charles W.

    2012-01-01

    As human activity in the Arctic increases, so does the risk of hydrocarbon pollution events. On site bioremediation of contaminated soil is the only feasible clean up solution in these remote areas, but degradation rates vary widely between bioremediation treatments. Most previous studies have focused on the feasibility of on site clean-up and very little attention has been given to the microbial and functional communities involved and their ecology. Here, we ask the question: which microorganisms and functional genes are abundant and active during hydrocarbon degradation at cold temperature? To answer this question, we sequenced the soil metagenome of an ongoing bioremediation project in Alert, Canada through a time course. We also used reverse-transcriptase real-time PCR (RT-qPCR) to quantify the expression of several hydrocarbon-degrading genes. Pseudomonas species appeared as the most abundant organisms in Alert soils right after contamination with diesel and excavation (t = 0) and one month after the start of the bioremediation treatment (t = 1m), when degradation rates were at their highest, but decreased after one year (t = 1y), when residual soil hydrocarbons were almost depleted. This trend was also reflected in hydrocarbon degrading genes, which were mainly affiliated with Gammaproteobacteria at t = 0 and t = 1m and with Alphaproteobacteria and Actinobacteria at t = 1y. RT-qPCR assays confirmed that Pseudomonas and Rhodococcus species actively expressed hydrocarbon degradation genes in Arctic biopile soils. Taken together, these results indicated that biopile treatment leads to major shifts in soil microbial communities, favoring aerobic bacteria that can degrade hydrocarbons. PMID:22253877

  13. Interior Department Suggests Improvements for Offshore Arctic Oil and Gas Drilling

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2013-03-01

    Shell's "difficulties" during its 2012 program to drill offshore oil and natural gas exploration wells in the Alaskan Arctic Ocean "have raised serious questions regarding its ability to operate safely and responsibly in the challenging and unpredictable conditions offshore Alaska," according to the report "Review of Shell's 2012 Alaska Offshore Oil and Gas Exploration Program," issued by the U.S. Department of the Interior (DOI) on 8 March. Noting the company's lack of adequate preparation for drilling in the Arctic, its failure to deploy a specialized Arctic Containment System, and the grounding of the Kulluk drilling rig near Kodiak Island last December, the report recommends that Shell develop a comprehensive and integrated plan describing its future drilling program and related operations and that it commission a third-party audit of its management systems, including its safety and environmental management systems program.

  14. Report of the workshop on Arctic oil and gas recovery. [Offshore

    SciTech Connect

    Sackinger, W. M.

    1980-09-01

    Mission of the workshop was to identify research priorities for the technology related to Arctic offshore oil and gas production. Two working groups were formed on ice-related subjects and soil-related subjects. Instrumentation needed to accomplish some of the research objectives was also discussed. Results of a research priority allocation survey are summarized. (DLC)

  15. Mobilization and degradation of particulate organic carbon from retrogressive thaw slumps in the western Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Shakil, S.; Tank, S. E.; Kokelj, S.

    2016-12-01

    Rapid arctic climate warming has contributed to a significant intensification in the rate and occurrence of thermokarst features which can cause large quantities of frozen organic carbon to suddenly become an active part of the contemporary carbon cycle. Mobilized organic carbon becomes susceptible to bacterial decomposition to CO2, which can then act as a significant positive feedback to climate change. Increasingly, studies are showing dissolved organic carbon (DOC) released from thawing permafrost is highly biodegradable, however, we know little about the biodegradability of permafrost-derived particulate organic carbon (POC). On the Peel Plateau, NWT, Canada, where a warming and wetting climate has intensified the activity of massive retrogressive thaw slumps (RTS), and where some of the Arctic's largest RTS features occur, POC can be more than an order of magnitude greater in streams impacted by an RTS feature when compared to upstream, un-impacted locations, and this mobilization causes POC concentrations to be more than 200 times greater than DOC downstream of slumps. Furthermore, POC released from RTS features can be 6,000 to 13,000 years older than POC in un-impacted streams, indicating a significant mobilization of permafrost carbon in the particulate form. To determine the biodegradability of RTS-released POC in this region, incubations using water samples collected upstream, at, and downstream of RTS sites were conducted during the summer of 2015. Dissolved oxygen measurements were taken 1-2 times per day, and samples for POC and DOC concentration, SUVA254, and bacterial abundance were collected at 0 days, 7 days, and 11 days. Treatments containing a spike of RTS-runoff in filtered water declined in oxygen at a rate as much as 10 times greater than treatments containing filtered DOC controls and unfiltered upstream water indicating that the released of RTS-derived POC substantially increases carbon mineralization in impacted streams. This pool of

  16. Compositions and greenhouse gas emission factors of flared and vented gas in the Western Canadian Sedimentary Basin.

    PubMed

    Johnson, Matthew R; Coderre, Adam R

    2012-09-01

    A significant obstacle in evaluating mitigation strategies for flaring and venting in the upstream oil and gas industry is the lack of publicly available data on the chemical composition of the gas. This information is required to determine the economic value of the gas, infrastructure and processing requirements, and potential emissions or emissions credits, all of which have significant impact on the economics of such strategies. This paper describes a method for estimating the composition of solution gas being flared and vented at individual facilities, and presents results derived for Alberta, Canada, which sits at the heart of the Western Canadian Sedimentary Basin. Using large amounts of raw data obtained through the Alberta Energy Resources Conservation Board, a relational database was created and specialized queries were developed to link production stream data, raw gas samples, and geography to create production-linked gas composition profiles for approximately half of the currently active facilities. These were used to create composition maps for the entire region, to which the remaining facilities with unknown compositions were geographically linked. The derived data were used to compute a range of solution gas composition profiles and greenhouse gas emission factors, providing new insight into flaring and venting in the region and enabling informed analysis of future management and mitigation strategies. Accurate and transparent determination of environmental impacts of flaring and venting of gas associated with oil production, and potential benefits of mitigation, is severely hampered by the lack of publicly available gas composition data. In jurisdictions within the Western Canadian Sedimentary Basin, frameworks exist for regulating and trading carbon offset credits but current potential for mitigation is limited by a lack of standardized methods for calculating CO2 equivalent emissions. The composition and emission factor data derived in this paper

  17. Widespread and rapid thermokarst development in a region of very cold continuous permafrost in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Farquharson, L. M.; Romanovsky, V. E.; Cable, W.; Walker, D. A.

    2016-12-01

    Climate warming in regions of ice-rich permafrost can result in widespread thermokarst development which can have drastic impacts on ecosystem processes and human infrastructure. Numerous studies have demonstrated that local permafrost degradation is occurring in areas of relatively "warm" permafrost, yet few have acknowledged nor documented the vulnerability of cold permafrost to degradation. In this study we present the first dataset coupling observations of ice-wedge degradation and thermokarst development with on-site continuous ground temperature data. We show evidence of widespread permafrost degradation at three monitoring sites underlain by continuous permafrost, in the Canadian High Arctic (73 to 79°N). Across all sites, the lack of a substantial organic protective layer makes the permafrost vulnerable to increases in summer temperature. At the start of our ground observation period, ice wedges at each site showed little to no evidence of degradation, suggesting that this recent disturbance is unprecedented during the Holocene. During the last decade, at all sites, we observed a warming trend for climate and ground temperature, leading to an increase in active layer depth, ice-wedge melting, and subsequent ground subsidence. Between 2005 and 2013, active layer depth increased at Isachsen, Mould Bay and Green Cabin by up to 20, 30, and 40 cm respectively. This lead to trough deepening at Green Cabin and new development followed by further deepening of troughs at Mould Bay and Isachsen. To measure elevation changes caused by thermokarst development, and establish a baseline for future monitoring, we used structure from motion (SfM) photogrammetry to derive a high spatial resolution digital terrain model at each site. Local distribution of thermokarst landforms were quantified using high-resolution spectral satellite imagery at an annual resolution between 2010 and 2015 and indicate that ice-wedge trough development is widespread within at least a 1 km

  18. Rapid changes in biogeochemical cycling across multiple scales in stream and river networks of the western Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Tank, S. E.; Kokelj, S. V.; Bulger, C. A.; Shakil, S.; Zolkos, S.; St Louis, V. L.; St Pierre, K.; McClelland, J. W.; Striegl, R. G.

    2016-12-01

    The flux and processing of biogeochemical constituents within stream and river networks is intricately linked to current, and changing, processes on land. In the western Canadian Arctic, recent work has documented a significant change in these land-to-freshwater connections, with a near 20% increase in the combined flux of dissolved organic, and inorganic carbon (DOC, DIC) at the mouth of the Mackenzie River over the past 40 years. This change is occurring over a potentially vast spatial scale: the Mackenzie watershed drains 1.5M km2 of permafrost-affected terrain. To understand the mechanisms underlying these large-scale observations, direct investigations at the sub-catchment scale are required. Within the greater Mackenzie catchment, one region undergoing rapid climate-induced change is the Peel Plateau, where the ubiquity of massive ground ice causes permafrost thaw to manifest as large retrogressive thaw slump (RTS) features, which can mobilize millions of cubic meters of sediment downslope and downstream. Soils in this region are comprised of deep, mineral-rich glacial tills, which appears to combine with significant RTS sediment mobilization to cause the effects of permafrost thaw to be strongly mediated by particle- and mineral-associated processes. At a direct level, these effects are striking: particulate organic carbon (POC) concentrations increase by up to two orders of magnitude downstream of slumps, while a similar increase in dissolved minerals is accompanied by a decrease in CO2, suggesting an important role for mineral weathering in this region's changing carbon cycle. However, these direct effects also have important indirect implications for biogeochemical change. For example, while RTSs release DOC of low aromaticity and high degradeability - as found in other permafrost-affected landscapes - the presence of mineral-rich suspended sediment appears to sequester DOC downstream of slumps. Beyond the carbon cycle, RTS sediment mobilization is

  19. Regional variation in radionuclide concentrations and radiation dose in caribou (Rangifer tarandus) in the Canadian Arctic; 1992-94.

    PubMed

    Macdonald, C R; Ewing, L L; Elkin, B T; Wiewel, A M

    1996-04-05

    Gamma-emitting radionuclides and 210Po, an alpha-emitting product of the 238U decay chain, were analysed in tissues from 16 caribou (Rangifer tarandus) collections in the Canadian North between 1992 and 1994. The study was conducted to determine the regional variability of anthropogenic and natural radionuclides in Canadian caribou, and to estimate the background radiation dose to caribou tissues. 137Cs, 40K, 210Pb and 210Po were consistently found in most herds. Mean muscle 137Cs varied from below detection limits on Banks Island to 231 Bq kg-1 wet weight (ww) in the Beverly herd in the central Arctic. Comparison of 1992-94 levels with published values from the 1960s and 1980s showed that 137Cs in caribou is declining with an effective half-life (Teff) of 9.9 years. The highest mean bone and liver 210Pb activities were observed on south Baffin Island, which included one bone sample with 3800 Bq kg-1 ww of 210Pb and 3070 Bq kg-1 ww of 210Po. The distribution of 137Cs and 210Pb between herds was attributed to higher atmospheric deposition rates between 60 and 65 degrees N, and changes in plant community structure and lichen species composition. The highest mean absorbed dose (30 mGy year-1) was observed in 1993 in the liver of caribou from Lake Harbour. This dose translated into a weighted absorbed dose of 300 mGy year-1, assuming a radiation weighting factor (wR) of 10 to account for the increased biological efficiency of alpha particles for deterministic effects. The Lake Harbour site also had the highest individual weighted absorbed dose in bone (810 mGy year-1) and liver (530 mGy year-1) in the study. There was no significant relationship between bone 210Pb activity and age for individual or pooled herds, indicating that the estimated doses are probably present throughout the lifetime of the caribou. Because some herds number several hundred thousand individuals, collective doses may also be very high. As yet, there have been no reports of observable effects due

  20. Mercury speciation in brain tissue of polar bears (Ursus maritimus) from the Canadian Arctic.

    PubMed

    Krey, Anke; Kwan, Michael; Chan, Hing Man

    2012-04-01

    Methylmercury (MeHg) is a neurotoxicant that has been found at elevated concentrations in the Arctic ecosystem. Little is known about its internal dose in wildlife such as polar bears. We measured concentrations of mercury (Hg) in three different brain regions (cerebellum, frontal lobe and brain stem) of 24 polar bears collected from the Nunavik, Canada between 2000 and 2003. Speciation of Hg was measured by High Performance Liquid Chromatography coupled to Inductively Coupled Plasma Mass Spectroscopy (HPLC-ICP-MS). Concentrations of mean total Hg in brain tissue were up to 625 times lower (0.28 ± 0.07 mg kg(-1) dry weight (dw) in frontal lobe, 0.23 ± 0.07 mg kg(-1) dw in cerebellum and 0.12 ± 0.0 3mg kg(-1) dw in brain stem) than the mean total Hg concentration previously reported in polar bear liver collected from Eastern Baffin Island. Methylmercury (MeHg) accounted for 100% of the Hg found in all three brain regions analyzed. These results suggest that polar bear might reduce the toxic effects of Hg by limiting the uptake into the brain and/or decrease the rate of demethylation so that Hg can be excreted from the brain more easily. The toxicokinetics and the blood-brain-barrier mechanisms of polar bears are still unknown and further research is required. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Western Canadian Arctic ringed seal organic contaminant trends in relation to sea ice break-up.

    PubMed

    Gaden, A; Ferguson, Steve H; Harwood, L; Melling, H; Alikamik, J; Stern, G A

    2012-04-17

    The association between changing sea ice conditions and contaminant exposure to Arctic animals interests Inuvialuit harvesters, communities, and researchers. We examined organochlorine contaminant (OC) concentrations in the blubber of 90 male adult ringed seals (Phoca hispida) sampled from the subsistence harvest in Ulukhaktok (formerly Holman), NT, Canada, just prior to break-up of the sea ice (1993-2008). OC blubber concentrations were assessed with respect to year and sea ice break-up date. HCB and age- and blubber-adjusted concentrations of p,p'-DDT and ΣCHB (chlorobornane) significantly decreased over the study period. With respect to the timing of the spring break-up, highly lipophlic OCs, such as p,p'-DDE and PCB 153, were higher during years of early ice clearing (at least 12 days earlier than the mean annual break-up date), whereas no trends were observed for α, β, and γ isomers of HCH, trans- and cis-chlordane, oxychlordane, or ΣCHB. The higher contaminant concentrations found in earlier break-up years is likely due to earlier and/or increased foraging opportunities. This situation also has potential for enhancing bioaccumulation and biomagnification of contaminants over the long-term if projected changes continue to result in lighter and earlier ice conditions.

  2. Optical turbulence profiling with SloDAR in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Maire, Jérôme; Mieda, Etsuko; Steinbring, Eric; Murowinski, Richard; Graham, James R.; Carlberg, Raymond; Wright, Shelley A.; Law, Nicholas M.; Sivanandam, Suresh

    2014-07-01

    The Earth's polar regions offer unique advantages for ground-based astronomical observations with its cold and dry climate, long periods of darkness, and the potential for exquisite image quality. We present preliminary results from a site-testing campaign during nighttime from October to November 2012 at the Polar Environment Atmospheric Research Laboratory (PEARL), on a 610-m high ridge near the Eureka weatherstation on Ellesmere Island, Canada. A Shack-Hartmann wavefront sensor was employed, using the Slope Detection and Ranging (SloDAR) method. This instrument (Mieda et al, this conference) was designed to measure the altitude, strength and variability of atmospheric turbulence, in particular for operation under Arctic conditions. First SloDAR optical turbulence profiles above PEARL show roughly half of the optical turbulence confined to the boundary layer, below about 1 km, with the majority of the remainder in one or two thin layers between 2 km and 5 km, or above. The median seeing during this campaign was measured to be 0.65 arcsec.

  3. Pressure-temperature conditions in granulite facies rocks of the northern Canadian Shield, Arctic Canada

    SciTech Connect

    Frisch, T.

    1985-01-01

    The northernmost part of the Churchill Structural Province of the Canadian Shield, underlying 60,000 km/sup 2/ of southeastern Ellesmere Island, Coburg Island and eastern Devon Island, consists of granulite facies metasedimentary, meta-igneous and plutonic intrusive rocks 2400 to 1900 m.y. old. Garnet+pyroxene+plagioclase of quartzofeldspathic gneisses from Ellesmere and Coburg islands indicate pressures, at 750/sup 0/C, ranging from greater than or equal to 6 to approx. 4kb; the lower pressures are derived largely, but not solely, from rim compositions. Similar rocks from Devon Island consistently indicate higher pressures of 6 to 7 kb. Garnet and plagioclase cores in sillimanite+cordierite-rich pelitic gneisses give pressures between 5 and 6.5 kb at 750/sup 0/C, the highest pressures being found in Devon Island rocks. Orthopyroxene+cordierite symplectites around garnet in magnesian metapelites indicate pressures under 4 kb at 650/sup 0/C. All cordierite is clearly of retrograde origin, having formed as a result of decompression during uplift, but even the highest pressures determined fall below the stability limit of cordierite in metapelites. Circumstantial evidence exists for the former stable coexistence of orthopyroxene+sillimanite, which would attest to pressures well in excess of 7 kb, but existing geobarometric equilibria have been strongly influenced by retrograde processes. Retrograde pressure-temperature conditions may well predominate in many granulite terranes but are not always recognized due to a scarcity of suitable mineral assemblages.

  4. Tumebacillus permanentifrigoris gen. nov., sp. nov., an aerobic, spore-forming bacterium isolated from Canadian high Arctic permafrost.

    PubMed

    Steven, Blaire; Chen, Min Qun; Greer, Charles W; Whyte, Lyle G; Niederberger, Thomas D

    2008-06-01

    A Gram-positive, aerobic, rod-shaped bacterium (strain Eur1 9.5(T)) was isolated from a 9-m-deep permafrost sample from the Canadian high Arctic. Strain Eur1 9.5(T) could not be cultivated in liquid medium and grew over the temperature range 5-37 degrees C; no growth was observed at 42 degrees C and only slow growth was observed at 5 degrees C following 1 month of incubation. Eur1 9.5(T) grew over the pH range 5.5-8.9 and tolerated NaCl concentrations of 0-0.5 % (w/v). Eur1 9.5(T) grew heterotrophically on complex carbon substrates and chemolithoautotrophically on inorganic sulfur compounds, as demonstrated by growth on sodium thiosulfate and sulfite as sole electron donors. Eur1 9.5(T) contained iso-C(15 : 0) as the major cellular fatty acid and menaquinone 7 (MK-7) as the major respiratory quinone. The cell-wall peptidoglycan was of type A1gamma. The DNA G+C content was 53.1 mol%. The 16S rRNA gene sequence of strain Eur1 9.5(T) was only distantly related (

  5. Land-Sea relationships of climate-related records: example of the Holocene in the eastern Canadian Arctic and Greenland

    NASA Astrophysics Data System (ADS)

    de Vernal, Anne; Fréchette, Bianca; Hillaire-Marcel, Claude

    2017-04-01

    Anne de Vernal, Bianca Fréchette, Claude Hillaire-Marcel Important progresses have been made to reconstruct climate and ocean changes through time. However, there is often a hiatus between the land-based climate reconstructions and paleoceanographical data. The reconstructed parameters are not the same (e.g. surface air temperature vs. sea-surface temperature). Moreover, the spatial (local to regional) and temporal dimensions (seasonal, annual to multi-decadal) of proxy-data are often inconsistent, thus preventing direct correlation of time series and often leading to uncertainties in multi-site, multi-proxy compilations. Here, we address the issue of land-sea relationships in the eastern Canadian Arctic-Baffin Bay-Labrador Sea-western Greenland based on the examination of different climate-related information from marine cores (dinocysts) collected nearshore vs. offshore, ice cores (isotopes), fjord and lake data (pollen). The combined information tends to indicate that "climate" changes are not easily neither adequately captured by temperature and temperature shifts. However, the seasonal contrast of temperatures seems to be a key parameter. Whereas it is often attenuated offshore, it is generally easy to reconstruct nearshore, where water stratification is usually stronger. The confrontation of data also shows a relationship between ice core data and sea-ice cover and/or sea-surface salinity, suggesting that air-sea exchanges in basins surrounding ice sheets play a significant role with respect to their isotopic composition. On the whole, combined onshore-offshore data consistently suggest a two-step shift towards optimal summer and winter conditions the circum Baffin Bay and northern Labrador Sea at 7.5 and 6 ka BP. These delayed optimal conditions seem to result from ice-meltwater discharges maintaining low salinity conditions in marine surface waters and thus a strong seasonality.

  6. Mass balance of the Canadian Arctic Archipelago using a combination of remote sensing and climate modeling techniques.

    NASA Astrophysics Data System (ADS)

    Ciraci, E.; Velicogna, I.; Rignot, E. J.; Mouginot, J.; van den Broeke, M. R.

    2014-12-01

    The Canadian Arctic Archipelago (CAA) hosts some of the largest glaciers and ice caps (GIC) outside Greenland and Antarctica and contains one-third of the global volume of land ice outside the ice sheets. Recent observations from satellite and airborne data indicate a large mass loss in that region. Here, we use time series of time-variable gravity from the NASA/DLR GRACE mission using a mascon approach to update the ice mass balance of this region till present. We find a mass loss of 73 Gt/year for April 2003 - December 2013. The mass loss per unit area is disproportionally large compared to that of the entire Greenland Ice Sheet. At the basin scale, we examine laser altimetry records from NASA's ICESat-1 (2003-2009) and Operation IceBridge's Airborne Topographic Mapper (ATM) to delineate areas of thinning and compare the results with surface mass balance (SMB) output products from the Regional Atmospheric and Climate Model (RACMO). We detect the signature of enhanced thinning along some of the CAA fast moving glaciers. Finally, we assemble a reference map of ice velocity from satellite radar interferometry, which we combine with existing ice thickness data to assess the mass flux and state of mass balance of the largest, fast-moving glaciers. Ice velocity from different years (1996 - 2006 - 2013) is used to construct time series of mass loss from the mass budget method. Combining these different sets of information, we address the issue of the partitioning of the mass loss between changes in SMB (essentially melt) and changes in ice dynamics (acceleration of glacier flow) to provide insights about the cause of the CAA change in mass balance in the last decades.

  7. New species of Chaetozone and Tharyx (Polychaeta: Cirratulidae) from the Alaskan and Canadian Arctic and the Northeastern Pacific, including a description of the lectotype of Chaetozone setosa Malmgren from Spitsbergen in the Norwegian Arctic.

    PubMed

    Blake, James A

    2015-02-18

    Eight new species of cirratulid polychaetes of the genus Chaetozone from the Alaskan (Beaufort Sea) and Canadian Arctic (Baffin Island, Baffin Bay, Labrador, Hudson Strait, and Hudson Bay) and the Northeastern Pacific are reported together with two new species of Tharyx from the Alaskan Beaufort Sea and the Strait of Juan de Fuca. The new species of Chaetozone and Tharyx are compared with related species; distinct species groups within these genera are discussed. A redescription of C. setosa Malmgren, 1867, the type species of the genus from Spitsbergen, based on a lectotype and associated paralectotypes designated by the late Dr. Mary E. Petersen is presented. A review of characters important in the taxonomy of the genera Chaetozone and Tharyx is presented. A key to species of Chaetozone from the Northeastern Pacific and North American Arctic is provided.

  8. The application of ERTS imagery to monitoring Arctic sea ice. [mapping ice in Bering Sea, Beaufort Sea, Canadian Archipelago, and Greenland Sea

    NASA Technical Reports Server (NTRS)

    Barnes, J. C. (Principal Investigator); Bowley, C. J.

    1974-01-01

    The author has identified the following significant results. Because of the effect of sea ice on the heat balance of the Arctic and because of the expanding economic interest in arctic oil and minerals, extensive monitoring and further study of sea ice is required. The application of ERTS data for mapping ice is evaluated for several arctic areas, including the Bering Sea, the eastern Beaufort Sea, parts of the Canadian Archipelago, and the Greenland Sea. Interpretive techniques are discussed, and the scales and types of ice features that can be detected are described. For the Bering Sea, a sample of ERTS-1 imagery is compared with visual ice reports and aerial photography from the NASA CV-990 aircraft. The results of the investigation demonstrate that ERTS-1 imagery has substantial practical application for monitoring arctic sea ice. Ice features as small as 80-100 m in width can be detected, and the combined use of the visible and near-IR imagery is a powerful tool for identifying ice types. Sequential ERTS-1 observations at high latitudes enable ice deformations and movements to be mapped. Ice conditions in the Bering Sea during early March depicted in ERTS-1 images are in close agreement with aerial ice observations and photographs.

  9. Buried glacier ice in permafrost, a window to the past: examples from Bylot Island, Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Fortier, D.; Coulombe, S.; Kanevskiy, M. Z.; Paquette, M.; Shur, Y.; Stephani, E.

    2011-12-01

    Bylot Island is located north of Baffin Island (73°N, 80°W) and is extensively covered by an ice cap and its outlet glaciers flowing towards the arctic lowland of the Lancaster formation. During summers of 2009 and 2011 several active-layer detachment slides exposed large massive ice bodies and other types of debris-rich ice that were interpreted as buried glacier ice. The upper part of the massive ice and debris-rich ice were usually in contact with various types of ice-contact or glacio-fluvial sediments and in some cases they were covered by mass wasting/colluvial deposits. This suggests that their preservation was likely related to burial of the ice and refreezing of the overlying sediments following permafrost aggradation. A preliminary analysis of the ice facies and ice crystals revealed the presence of four distinct types of ice: 1) clear-ice bodies with very few sediment and no organic inclusions. The ice crystals were large (cm), randomly oriented and air bubbles were observed at the junction of crystals. These characteristics could potentially indicate an englacial (snow-neve metamorphism) origin for these clear ice bodies; 2) large, meter thick, clear ice layers with no sediment, nor organics. The ice crystals were large (cm), several cm long, oriented in the same direction, and vertically aligned. These characteristics could potentially point to water that refroze in a tunnel incised in englacial ice; 3) Successive, mm to cm thick, ice layers, separated by undulating sand and gravel bands also containing cobles to boulder size rock fragments. These characteristics could potentially represent regelation ice formed at the base of glaciers and incorporated to the glacier sole; 4) mm to cm suspended aggregate of fine-grained sediments in clear ice. These micro-suspended and suspended cryostructures were sometimes deformed and aligned in the form of thin (mm) undulating layers. These micro-structures were very similar to basal ice facies, presumably

  10. Molecular analysis of bacterial communities from a Canadian high Arctic polythermal glacier

    NASA Astrophysics Data System (ADS)

    Bhatia, M.; Sharp, M.; Foght, J.

    2003-04-01

    The goal of this study is to characterize the bacterial communities beneath, on, and adjacent to a high Arctic polythermal glacier, with a view to understanding the origins of the subglacial microbial population. The study site is John Evans Glacier (JEG), Ellesmere Island, Canada. JEG is a polythermal glacier consisting of a core of ice at the pressure melting point, surrounded by an outer layer of cold ice. Basal melting and seasonal inputs of meltwater from the glacier surface provide liquid water for subglacial microbial life. Samples were collected from the subglacial, supraglacial, and proglacial environments at JEG. Subglacial samples included basal ice and water that had been stored beneath the glacier. Dry snow, wet snow, and water from supraglacial streams were collected as representatives of the supraglacial environment, which changes in character through the melt season. Sediments and algal mats were collected from an area directly in front of the glacier terminus and along a transect adjacent to the glacier to reflect the developing proglacial environment. Hydrochemical analyses were conducted to assess the role of microbial activity in biogeochemical processes. To compare the bacterial communities, molecular techniques were applied to total community DNA that was released from the samples by a physical cell disruption technique. The polymerase chain reaction (PCR) was used with bacterial-specific primers, one of which was fluorescently labeled, to amplify community 16S rDNA genes. Single digestions with the restriction enzymes HaeIII and HhaI were performed to conduct inter- and intra-community comparisons of the terminal restriction fragment length polymorphisms (tRFLPs) of the fluorescently tagged amplified 16S rDNA genes. Preliminary results indicate that although some species are present throughout the different environments, several species are unique to each particular habitat. Further study of replicate tRFLP data and statistical analyses will

  11. The use of airborne radar reflectometry to establish snow/firn density distribution on Devon Ice Cap, Canadian Arctic: A path to understanding complex heterogeneous internal layering patterns

    NASA Astrophysics Data System (ADS)

    Rutishauser, A.; Grima, C.; Sharp, M. J.; Blankenship, D. D.; Young, D. A.; Dowdeswell, J. A.

    2014-12-01

    The internal layer stratigraphy of polar ice sheets revealed by airborne radio-echo sounding (RES) contains valuable information about past ice sheet mass balance and dynamics. Internal layers in the Antarctic and Greenland ice sheets are considered to be isochrones and are continuous over several hundreds of kilometres. In contrast, internal layers in Canadian Arctic ice caps appear to be very heterogeneous and fragmentary, consisting of highly discontinuous layers that can be traced over only a few to several tens of kilometres. Internal layers most likely relate to former ice surfaces (the upper few meters of snow/firn), the properties which are directly influenced by atmospheric conditions including the air temperature, precipitation rate, and prevailing wind pattern. We hypothesize that the heterogeneous and complex nature of layers in the Canadian Arctic results from highly variable snow and firn conditions at the surface. Characterizing surface properties such as variations in the snow/firn density from dry to wet snow/firn, as well as high-density shallow ice layers and lenses of refrozen water can help to elucidate the complex internal layer pattern in the Canadian Arctic ice caps. Estimates of the snow/firn surface density and roughness can be derived from reflectance and scattering information using the surface radar returns from RES measurements. Here we present estimates of the surface snow/firn density distribution over Devon Ice Cap in the Canadian Arctic derived by the Radar Statistical Reconnaissance (RSR) methodology (Grima et al., 2014, Planetary & Space Sciences) using data collected by recent airborne radar sounding programs. The RSR generates estimates of the statistical distribution of surface echo amplitudes over defined areas along a survey transect. The derived distributions are best-fitted with a theoretical stochastic envelope, parameterized with the signal reflectance and scattering, in order to separate those two components. Finally

  12. Development of the MESH hydrological model in two Canadian arctic basins

    NASA Astrophysics Data System (ADS)

    Seglenieks, F.; Soulis, E.; Quinton, B.; Hayashi, M.; Spence, C.

    2009-05-01

    The research network "Improved Processes and Parameterisation and Prediction in Cold Regions" (IP3) intends to improve the scientific understanding of processes and predictions and improve understanding of the ways in which these challenges affect human health and the natural environment in addition to strengthening Canada's scientific capacity. Through this network there are close interactions between researchers in the field examining the hydrological processes and modellers simulating those processes using hydrological models. This study examines the results of this collaboration in two research basins located in northern Canada: Scotty Creek and Baker Creek. The Scotty Creek watershed flows into the Liard River near its confluence with the Mackenzie River at Fort Simpson, it has a drainage area of approximately 150 km2. The watershed consists of a broad peatland complex with islands of sparse woodland, underlain by permafrost, surrounded by channel fens and flat bogs. The Baker Creek watershed is a series of interconnected lakes draining an area of 150 km2 located north of Great Slave Lake. Typical of Canadian Shield drainage basins, the landscape is taiga woodland and boreal forest. The hydrological model MESH, currently being developed by Environment Canada, was used to simulate the hydrological processes in the basins. Results were compared to the detailed field measurements available from the basins for such variables as soil moisture, soil temperature, and snow water equivalent. Based on this comparison, various processes such as the partitioning of flow within a grid square and the contributing area of the basin were modified in the model. These modifications led to an improvement in the MESH simulations and a better understanding of the important hydrological processes occurring in these northern basins.

  13. Canadian natural gas exports to the US: a monopolistic intertemporal analysis

    SciTech Connect

    Daniel, T.E.; Goldberg, H.M.; Weyant, J.P.

    1984-10-01

    Active debate over the appropriate level and pricing of energy exports to the US underscores the need for a consistent framework for evaluating gas export quantities and prices that takes into account current and projected Canadian resources and domestic demand as well as US market forces. The authors describe an analytical model, then point out some interesting characteristics of continental gas trade and an intertemporal analysis of supply and demand over the next 20 years. They conclude with planned modifications to the model and future research plans. 10 references, 3 figures, 2 tables.

  14. Remarkable separability of circulation response to Arctic sea ice loss and greenhouse gas forcing

    NASA Astrophysics Data System (ADS)

    McCusker, K. E.; Kushner, P. J.; Fyfe, J. C.; Sigmond, M.; Kharin, V. V.; Bitz, C. M.

    2017-08-01

    Arctic sea ice loss may influence midlatitude climate by changing large-scale circulation. The extent to which climate change can be understood as greenhouse gas-induced changes that are modulated by this loss depends on how additive the responses to the separate influences are. A novel sea ice nudging methodology in a fully coupled climate model reveals that the separate effects of doubled atmospheric carbon dioxide (CO2) concentrations and associated Arctic sea ice loss are remarkably additive and insensitive to the mean climate state. This separability is evident in several fields throughout most of the year, from hemispheric to synoptic scales. The extent to which the regional response to sea ice loss sometimes agrees with and sometimes cancels the response to CO2 is quantified. The separability of the responses might provide a means to better interpret the diverse array of modeling and observational studies of Arctic change and influence.

  15. Synchronous starphotometry and lidar measurements at Eureka in High Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Baibakov, K.; O'Neill, N. T.; Ivanescu, L.; Duck, T. J.; Perro, C.; Herber, A.; Schulz, K.-H.; Schrems, O.

    2015-02-01

    We present recent progress related to the night-time retrievals of aerosol and cloud optical depth using starphotometry over the PEARL (Polar Environmental Atmospheric Research Laboratory) station at Eureka (Nunavut, Canada) in the High Arctic (80° N, 86° W). In the spring of 2011 and 2012, the SPSTAR starphotometer was employed to acquire aerosol optical depth (AOD) measurements while vertical aerosol and cloud backscatter coefficient profiles were acquired using the CANDAC Raman Lidar (CRL). Several events were detected and characterized using starphotometry-lidar synergy: aerosols (short term aerosol events on 9 and 10 March 2011); a potential multi-night aerosol event across three polar nights (13-15 March 2012), a thin cloud event (21 February 2011) and a very low altitude ice crystals (10 March 2011). Using a simple backscatter coefficient threshold criterion we calculated fine and coarse (sub and super-micron) mode AODs from the vertically integrated CRL profiles. These were compared with their starphotometry analogues produced from a spectral deconvolution algorithm. The process-level analysis showed, in general, good agreement in terms of the physical coherence between high frequency starphotometry and lidar data. We argue that R2 (coefficient of determination) is the most robust means of comparing lidar and starphotometer data since it is sensitive to significant optico-physical variations associated with these two independent data sources while being minimally dependent on retrieval and calibration artifacts. Differences between the fine and course mode components of the starphotometry and lidar data is clearly also useful but is more dependent on such artifacts. Studying climatological seasonal aerosol trends necessitates effective cloud-screening procedures: temporal and spectral cloud screening of starphotometry data was found to agree moderately well with temporal cloud screening results except in the presence of thin homogeneous cloud. We conclude

  16. Concentrations of mercury in tissues of beluga whales (Delphinapterus leucas) from several communities in the Canadian Arctic from 1981 to 2002.

    PubMed

    Lockhart, W L; Stern, G A; Wagemann, R; Hunt, R V; Metner, D A; DeLaronde, J; Dunn, B; Stewart, R E A; Hyatt, C K; Harwood, L; Mount, K

    2005-12-01

    Beluga whales have been hunted for food by Native People in the Canadian Arctic since prehistoric time. Here we report the results of analyses of total mercury in samples of liver, kidney, muscle and muktuk from collections over the period 1981-2002. We compare these results with human consumption guidelines and examine temporal and geographic variation. Liver has been analyzed more frequently than other organs and it has been used as the indicator organ. Mercury accumulates in the liver of the whales over time so that the whale ages are usually linked statistically to their levels of mercury in liver. Virtually all the samples of 566 animals analyzed contained mercury in liver at concentrations higher than the Canadian consumption guideline of 0.5 microg g-1 (wet weight) for fish. (There is no regulatory guideline for concentrations in marine mammals in Canada.) Samples from locations in the Mackenzie Delta in the western Canadian Arctic and from Pangnirtung in the eastern Canadian Arctic were obtained more often than from other location and these offered the best chances to determine whether levels have changed over time. Statistical outlier points were removed and the regressions of (ln) mercury in liver on age were used to calculate the level of mercury in whales of age 13.1 years in order to compare age-adjusted levels at different locations. These age-adjusted levels and also the slopes of regressions suggested that levels have increased in the Mackenzie Delta over the sampling period although not in a simple linear fashion. Other locations had fewer collections, generally spread over fewer years. Some of them indicated differences between sampling times but we could not establish whether these differences were simply temporal variation or whether they were segments of a consistent trend. For example, the levels in whales from Arviat were considerably higher in 1999 than in 1984 but we have only two samples. Similarly, samples from Iqaluit in 1994 exceeded

  17. Greenhouse Gas Exchange and Biogeochemistry of Fertilized Canadian Plantation Forests

    NASA Astrophysics Data System (ADS)

    Basiliko, N.; Grayston, S. J.; Roy, R.; Mohn, W. W.; Yolova, V.; Prescott, C.

    2005-12-01

    Canada's ratification of the Kyoto Protocol in 2002 has raised questions of the role of ecosystem management as a tool to temporarily reduce the net greenhouse gas burden of the forestry industry and potentially generate emission offset credits. We examined growing season methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) fluxes, soil nutrient chemistry, and microbial biomass and CH4-oxidizing bacterial communities in 20-year-old sub-boreal lodgepole pine and maritime hemlock plantations under control conditions and simulated operational fertilization with N (200kg urea-N per ha, applied twice) and N, P, K, and micronutrients. CH4 uptake was significantly greater in the lodgepole pine site than in the hemlock site (152-221 and 57-81 micrograms CH4 consumed per square meter per hour), and there were no significant differences among treatments at either site. Among sites, treatments, and sampling times, CH4 uptake correlated positively with NH4 concentrations and negatively with extractable organic N:P quotients, indicating that this process may potentially be limited by nutrient availability to the CH4-oxidizing bacteria. N2O efflux was measured sporadically at a few flux collars, but was not significantly different from zero at any site, treatment, or time. Soil respiration (CO2 efflux) rates were faster in the hemlock than lodgepole pine site (243-409 and 100-266 milligrams CO2 per square meter per hour), and significant treatment differences were observed at individual times, though with fertilized plots exhibiting both faster and slower rates than controls. Soil respiration correlated significantly with microbial biomass C and N and NO3. Within each site, soil respiration, but not CH4 uptake, was positively correlated with soil temperature. New experiments examining the short-term effects of fertilization on greenhouse gas exchanges are underway, and both short and long-term effects will be evaluated in relation to changes in C storage in plant biomass

  18. Middle Pleistocene (?) buried glacial ice on Bylot Island, Canadian Arctic Archipleago

    NASA Astrophysics Data System (ADS)

    Fortier, D.; Godin, E.; Kanevskiy, M. Z.; Allard, M.

    2009-12-01

    Bylot Island is located north of Baffin Island (73°N, 80°W). More than the half of the island is covered by an ice cap and its outlet glaciers flowing towards the arctic lowland of the Lancaster formation. The study site comprises four main stratigraphic units. Overlying the shales (Tertiary) of the Lancaster Formation (500 m a.s.l.), a diamicton (unit 1) is covered by a “fossil forest-tundra” sequence (unit 2) containing abundant remains of trees and plants (Allard et al., submitted). Paleontological correlation of extinct species and reverse to normal palomagnetism polarities suggest a Late Pliocene to Early Pleistocene age for this unit. A sequence (unit 3) of ice-contact proximal to distal glacio-fluvial sediments overlies the organic beds. Paleomagnetic analysis showed that the upper glacio-fluvial sediments were likely deposited during the Brunhes polarity chron (younger than 0.73 Ma). The uppermost unit (unit 4) consists in a lodgement till containing clasts of Paleozoic limestone erratics. Based on amino acid ratios of shells fragments in the drift, Klassen (1993) suggested that this “foreign drift” was probably deposited during an "old" Quaternary glaciation named “Baffin glaciation” During July 2009 several active-layer detachment slides at the head of large gullies exposed large massive ice bodies located at the junction between units 3 and 4. A preliminary analysis of the ice facies and ice crystals revealed the presence of two distinct types of massive ice: 1) clear-ice bodies with very few sediments and no organic inclusions. The ice crystals were large (cm) and air bubbles were observed at the junction of crystals. These characteristics could potentially indicate an englacial origin for these clear ice bodies. In some places, the ice was stratified with undulating layers of sands and gravels. These micro-structures are very similar to basal ice facies we observed at the Matanuska Glacier in Alaska. The exposed massive ice sections were

  19. Understanding the Canadian oil sands industry's greenhouse gas emissions

    NASA Astrophysics Data System (ADS)

    Charpentier, Alex D.; Bergerson, Joule A.; MacLean, Heather L.

    2009-01-01

    The magnitude of Canada's oil sands reserves, their rapidly expanding and energy intensive production, combined with existing and upcoming greenhouse gas (GHG) emissions regulations motivate an evaluation of oil sands-derived fuel production from a life cycle perspective. Thirteen studies of GHG emissions associated with oil sands operations are reviewed. The production of synthetic crude oil (SCO) through surface mining and upgrading (SM&Up) or in situ and upgrading (IS&Up) processes is reported to result in emissions ranging from 62 to 164 and 99 to 176 kgCO2eq/bbl SCO, respectively (or 9.2-26.5 and 16.2-28.7 gCO2eq MJ-1 SCO, respectively), compared to 27-58 kgCO2eq/bbl (4.5-9.6 gCO2eq MJ-1) of crude for conventional oil production. The difference in emissions intensity between SCO and conventional crude production is primarily due to higher energy requirements for extracting bitumen and upgrading it into SCO. On a 'well-to-wheel' basis, GHG emissions associated with producing reformulated gasoline from oil sands with current SM&Up, IS&Up, and in situ (without upgrading) technologies are 260-320, 320-350, and 270-340 gCO2eq km-1, respectively, compared to 250-280 gCO2eq km-1 for production from conventional oil. Some variation between studies is expected due to differences in methods, technologies studied, and operating choices. However, the magnitude of the differences presented suggests that a consensus on the characterization of life cycle emissions of the oil sands industry has yet to be reached in the public literature. Recommendations are given for future studies for informing industry and government decision making.

  20. Fate and transport of Toxoplasma gondii oocysts in seasonally snow covered watersheds: a conceptual framework from a melting snowpack to the Canadian arctic coasts.

    PubMed

    Simon, Audrey; Poulin, Michel Bigras; Rousseau, Alain N; Ogden, Nicholas H

    2013-03-11

    Toxoplasma gondii is a zoonotic protozoan that causes serious illness in humans and infects animals worldwide, including the Canadian Arctic. Indeed, high prevalence of infection amongst Inuit has been recorded, possibly due to consumption of raw infected seal meat. Here we explore the hypothesis that T. gondii oocysts contaminate the coastal marine environment via surface runoff from across the boreal watershed, particularly during the snowmelt period. We propose a conceptual framework of the different processes governing the fate and transport of T. gondii oocysts from the melting snowpack to the Canadian arctic coast via the freshwater runoff. This framework identifies the feasibility of a transmission pathway of oocysts from contaminated soil to the marine environment, but also the complexity and multiplicity of mechanisms involved. In addition, the framework identifies knowledge gaps for guiding future studies on T. gondii oocysts. Furthermore, this work could be used as a tool to investigate the possible estuarine contamination by other faeces-borne pathogens transported via the spring freshet in seasonally snow covered watersheds.

  1. Robust increase in ocean heat transport into the Arctic under greenhouse gas forcing

    NASA Astrophysics Data System (ADS)

    Oldenburg, D.; Armour, K.; Thompson, L.

    2016-12-01

    seen under greenhouse gas forcing. We hypothesize that different mechanisms link AMOC and Arctic OHT under natural variability than under anthropogenic forcing.

  2. Influence of seabird colonies and other environmental variables on benthic community structure, Lancaster Sound Region, Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Bouchard Marmen, Mariève; Kenchington, Ellen; Ardyna, Mathieu; Archambault, Philippe

    2017-03-01

    The Canadian Arctic shelters millions of seabirds each year during the breeding season. By the excretion of important quantities of guano, seabirds locally concentrate nutrient-rich organic matter in the marine areas surrounding colonies. Seabirds, acting as biological vectors of nutrients, can markedly affect terrestrial ecosystems, but their influence on the structure of marine benthic communities is still under-studied. Sessile and long-lived megabenthic species can integrate environmental variation into marine food webs over long time frames. The objectives of this study were (1) to characterize the epifaunal and infaunal communities of the Lancaster Sound Region (LSR) and (2) to test the influence of the presence of seabird colonies and other environmental parameters on the structure of those benthic communities. Our prediction was that benthic diversity, number of taxa, total biomass of infauna and total density of epifauna and infauna, would be higher in areas with colonies present. Photos of the seafloor (data on epifauna) and grab samples (data on infauna) were taken at three control areas and at five areas near seabird colonies, within a depth range of 122 to 442 m. A database of 26 environmental parameters was built to study the environment-benthos relationships. Infauna, which was relatively uniform across the LSR, was numerically dominated by Annelida. Epifauna was much patchier, with each study area having unique epibenthic assemblages. Brittle stars were highly abundant in epifaunal communities, reaching 600 individuals per square meter. The presence of seabird colonies was not a major driver of benthic community structure in the LSR at the depths studied. Negative effects of colonies were detected on the density and number of taxa of infauna, perhaps due to top-down effects transmitted by the seabirds which feed in the water column and can directly reduce the quantity of food reaching the seabed. Sediment concentration of pigment, percent cover of

  3. Air-water exchange of anthropogenic and natural organohalogens on International Polar Year (IPY) expeditions in the Canadian Arctic.

    PubMed

    Wong, Fiona; Jantunen, Liisa M; Pućko, Monika; Papakyriakou, Tim; Staebler, Ralf M; Stern, Gary A; Bidleman, Terry F

    2011-02-01

    Shipboard measurements of organohalogen compounds in air and surface seawater were conducted in the Canadian Arctic in 2007-2008. Study areas included the Labrador Sea, Hudson Bay, and the southern Beaufort Sea. High volume air samples were collected at deck level (6 m), while low volume samples were taken at 1 and 15 m above the water or ice surface. Water samples were taken within 7 m. Water concentration ranges (pg L(-1)) were as follows: α-hexachlorocyclohexane (α-HCH) 465-1013, γ-HCH 150-254, hexachlorobenzene (HCB) 4.0-6.4, 2,4-dibromoanisole (DBA) 8.5-38, and 2,4,6-tribromoanisole (TBA) 4.7-163. Air concentration ranges (pg m(-3)) were as follows: α-HCH 7.5-48, γ-HCH 2.1-7.7, HCB 48-71, DBA 4.8-25, and TBA 6.4 - 39. Fugacity gradients predicted net deposition of HCB in all areas, while exchange directions varied for the other chemicals by season and locations. Net evasion of α-HCH from Hudson Bay and the Beaufort Sea during open water conditions was shown by air concentrations that averaged 14% higher at 1 m than 15 m. No significant difference between the two heights was found over ice cover. The α-HCH in air over the Beaufort Sea was racemic in winter (mean enantiomer fraction, EF = 0.504 ± 0.008) and nonracemic in late spring-early summer (mean EF = 0.476 ± 0.010). This decrease in EF was accompanied by a rise in air concentrations due to volatilization of nonracemic α-HCH from surface water (EF = 0.457 ± 0.019). Fluxes of chemicals during the southern Beaufort Sea open water season (i.e., Leg 9) were estimated using the Whitman two-film model, where volatilization fluxes are positive and deposition fluxes are negative. The means ± SD (and ranges) of net fluxes (ng m(-2) d(-1)) were as follows: α-HCH 6.8 ± 3.2 (2.7-13), γ-HCH 0.76 ± 0.40 (0.26-1.4), HCB -9.6 ± 2.7 (-6.1 to -15), DBA 1.2 ± 0.69 (0.04-2.0), and TBA 0.46 ± 1.1 ng m(-2) d(-1) (-1.6 to 2.0).

  4. Trends of polybrominated diphenyl ethers and hexabromocyclododecane in eggs of Canadian Arctic seabirds reflect changing use patterns.

    PubMed

    Braune, Birgit M; Letcher, Robert J; Gaston, Anthony J; Mallory, Mark L

    2015-10-01

    Due to the substantial use and release of polybrominated diphenyl ether (PBDE) flame retardants in North America, PBDE concentrations in North American marine biota are among the highest in the world. In this study, we compared PBDE concentrations and congener patterns in eggs of five seabird species (thick-billed murres, northern fulmars, black guillemots, glaucous gulls, black-legged kittiwakes) breeding at a colony in the Canadian Arctic in 1993, 2008 and 2013. Temporal trends of PBDEs (1975-2014) and another flame retardant, hexabromocyclododecane (HBCD) (2003-2014), were also examined in eggs of two seabird species, the thick-billed murre and northern fulmar. BDE-47 generally dominated the BDE congener profiles in eggs of all five species. Glaucous gulls had the highest concentrations of both ΣPBDE and BDE-47, and northern fulmars, the lowest. ΣPBDE concentrations increased exponentially in eggs of both thick-billed murres and northern fulmars from 1975 to 2003 with doubling times of 9.1 years in the murres and 7.2 years in the fulmars. From 2003 to 2008/09, ΣPBDE decreased rapidly in the murres and fulmars to concentrations not significantly different from those recorded in 1975 and 1987 for each species. After 2008/09, ΣPBDE concentrations plateaued. BDE-47 followed a similar temporal trend to that of ΣPBDE concentrations. These concentration trends were consistent with the phase-out of the penta- and octa-BDE products from the North American market in the mid-2000s. There was an overall decline in concentrations of HBCD in murre eggs from 2003 to 2014, whereas concentrations in the fulmar eggs increased from 2003 to 2006 followed by a decline to 2014. The ratio of HBCD to BDE-47 suggests that northern fulmars showed more of a European contaminant signature, and thick-billed murres, more of a North American signature. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  5. Identification and determination of the dechlorination products of Dechlorane 602 in Great Lakes fish and Arctic beluga whales by gas chromatography-high resolution mass spectrometry.

    PubMed

    Shen, Li; Jobst, Karl J; Helm, Paul A; Reiner, Eric J; McCrindle, Robert; Tomy, Gregg T; Backus, Sean; Brindle, Ian D; Marvin, Chris H

    2012-11-01

    During the course of our studies of in-use chlorinated flame retardants, such as Dechlorane Plus(®) and Dechloranes 602 and 604, blubber of beluga whales from the Canadian Arctic and lake trout and whitefish from the North American Great Lakes were found to contain two novel dechlorination products of Dechlorane 602 (Dec602). The structures of these compounds were characterized by experiments performed using both gas chromatography-high resolution mass spectrometry and Fourier transform mass spectrometry with a prepared technical mixture of monohydro and dihydroDec602 derivatives. These Dec602 derivatives are analogous to the well-known monohydro and dihydro photochemical degradation products of Mirex. The ratio of the two monohydroDec602 diastereomers varied between Lake Ontario fish and those from the upper lakes, but only one isomer was found in Arctic beluga, indicating that one isomer is either more stable or more bioaccumulative. Dechlorane Plus(®), Dec603, and Dec 604 were not detected in Arctic beluga, but Dec602 and its monohydroDec602 derivative were measured in approximately equal concentrations, ranging from 25 to 300 pg/g lipid. In Great Lakes fish, concentrations of the monohydroDec602 derivatives were also close to those of Dec602, ranging from 2 to 67 ng/g lipid and were greatest in Lake Ontario. This study reports on the first measurements of dechlorane-related compounds in Arctic biota and the first detection of monohydroDec602 degradation products and their accumulation in biota.

  6. Migratory Connectivity at High Latitudes: Sabine's Gulls (Xema sabini) from a Colony in the Canadian High Arctic Migrate to Different Oceans.

    PubMed

    Davis, Shanti E; Maftei, Mark; Mallory, Mark L

    2016-01-01

    The world's Arctic latitudes are some of the most recently colonized by birds, and an understanding of the migratory connectivity of circumpolar species offers insights into the mechanisms of range expansion and speciation. Migratory divides exist for many birds, however for many taxa it is unclear where such boundaries lie, and to what extent these affect the connectivity of species breeding across their ranges. Sabine's gulls (Xema sabini) have a patchy, circumpolar breeding distribution and overwinter in two ecologically similar areas in different ocean basins: the Humboldt Current off the coast of Peru in the Pacific, and the Benguela Current off the coasts of South Africa and Namibia in the Atlantic. We used geolocators to track Sabine's gulls breeding at a colony in the Canadian High Arctic to determine their migratory pathways and wintering sites. Our study provides evidence that birds from this breeding site disperse to both the Pacific and Atlantic oceans during the non-breeding season, which suggests that a migratory divide for this species exists in the Nearctic. Remarkably, members of one mated pair wintered in opposite oceans. Our results ultimately suggest that colonization of favorable breeding habitat may be one of the strongest drivers of range expansion in the High Arctic.

  7. Migratory Connectivity at High Latitudes: Sabine’s Gulls (Xema sabini) from a Colony in the Canadian High Arctic Migrate to Different Oceans

    PubMed Central

    Davis, Shanti E.; Maftei, Mark; Mallory, Mark L.

    2016-01-01

    The world's Arctic latitudes are some of the most recently colonized by birds, and an understanding of the migratory connectivity of circumpolar species offers insights into the mechanisms of range expansion and speciation. Migratory divides exist for many birds, however for many taxa it is unclear where such boundaries lie, and to what extent these affect the connectivity of species breeding across their ranges. Sabine’s gulls (Xema sabini) have a patchy, circumpolar breeding distribution and overwinter in two ecologically similar areas in different ocean basins: the Humboldt Current off the coast of Peru in the Pacific, and the Benguela Current off the coasts of South Africa and Namibia in the Atlantic. We used geolocators to track Sabine’s gulls breeding at a colony in the Canadian High Arctic to determine their migratory pathways and wintering sites. Our study provides evidence that birds from this breeding site disperse to both the Pacific and Atlantic oceans during the non-breeding season, which suggests that a migratory divide for this species exists in the Nearctic. Remarkably, members of one mated pair wintered in opposite oceans. Our results ultimately suggest that colonization of favorable breeding habitat may be one of the strongest drivers of range expansion in the High Arctic. PMID:27973614

  8. An application of well data in oil and gas assessment-arctic national wildlife refuge

    USGS Publications Warehouse

    Nelson, P.H.; Schenk, C.J.; Bird, K.J.

    1998-01-01

    A current assessment of oil and gas resources in the Arctic National Wildlife Refuge (ANWR) 1002 Area by the U.S. Geological Survey relies upon seismic data, geological mapping of exposures south and west of the assessment area, and exploratory wells. Information obtained from wells up to 50 km west and north of ANWR is presented. It is emphasized that the synthesis of well data with other geological and geophysical data provides a quantitative foundation for resource estimates of ANWR.

  9. Analysis of Oil and Gas Production in the Arctic National Wildlife Refuge

    EIA Publications

    2004-01-01

    This study analyzed the impact on future oil imports and expenditures of opening the Arctic National Wildlife Refuge (ANWR) to petroleum development. High, low, and mean ANWR oil resource case projections were compared to the Annual Energy Outlook 2004 reference case. The study also examined whether potential synergies exist in opening ANWR to petroleum development and the construction of an Alaska gas pipeline from the North Slope to the lower 48 states.

  10. Proposed oil and gas exploration within the coastal plain of the Arctic National Wildlife Refuge, Alaska

    SciTech Connect

    Not Available

    1982-11-01

    The draft environmental impact statement describes the procedures and probable effects of aerial and geological surveying for oil and gas in the coastal area of Alaska's Arctic National Wildlife Refuge. The procedures provide for the protection of caribou caving areas and the avoidance of duplication in the survey activities. Temporary disturbances from seismic surveys would interfere with wildlife breeding and migration due to changes in the habitat. The Alaska National Interest Lands Conservation Act of 1980 provides the legal mandate for environmental assessment.

  11. Recent advances of packed column technology for gas dehydration and absorbent regeneration in arctic and off-shore gas production

    SciTech Connect

    Chen, G.K.

    1987-01-01

    In-depth revamp of dehydration and regeneration trayed columns with proprietary structured packings in arctic gas production will be presented in terms of throughput increase and mass transfer efficiency improvement achieved. Mathematical expressions that relate the column performance to operating variables such as absorbent temperature and concentration, ratio of absorbent to gas, degree of dehydration/regeneration and number of transfer units available are described. Equipment specification and performance between conventional tray design and packed column for off-shore application are also included. Initial capital investment versus subsequent net savings of numerous commercial installations are discussed.

  12. Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming

    NASA Astrophysics Data System (ADS)

    Hong, Wei-Li; Torres, Marta E.; Carroll, Jolynn; Crémière, Antoine; Panieri, Giuliana; Yao, Haoyi; Serov, Pavel

    2017-06-01

    Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of Spitsbergen (Storfjordrenna, ~380 m water depth). Modelling of the non-steady-state porewater profiles and observations of distinct layers of methane-derived authigenic carbonate nodules in the sediments indicate centurial to millennial methane emissions in the region. Results of temperature modelling suggest limited impact of short-term warming on gas hydrates deeper than a few metres in the sediments. We conclude that the ongoing and past methane emission episodes at the investigated sites are likely due to the episodic ventilation of deep reservoirs rather than warming-induced gas hydrate dissociation in this shallow water seep site.

  13. The Impact of a Lower Sea Ice Extent on Arctic Greenhouse Gas Exchange

    NASA Astrophysics Data System (ADS)

    Parmentier, Frans-Jan W.; Christensen, Torben R.; Lotte Sørensen, Lise; Rysgaard, Søren; McGuire, A. David; Miller, Paul A.; Walker, Donald A.

    2013-04-01

    Arctic sea ice extent hit a new record low in September 2012, when it fell to a level about two times lower than the 1979-2000 average. Record low sea ice extents such as these are often hailed as an obvious example of the impact of climate change on the Arctic. Less obvious, however, are the further implications of a lower sea ice extent on Arctic greenhouse gas exchange. For example, a reduction in sea ice, in consort with a lower snow cover, has been connected to higher surface temperatures in the terrestrial part of the Arctic (Screen et al., 2012). These higher temperatures and longer growing seasons have the potential to alter the CO2 balance of Arctic tundra through enhanced photosynthesis and respiration, as well as the magnitude of methane emissions. In fact, large changes are already observed in terrestrial ecosystems (Post et al., 2009), and concerns have been raised of large releases of carbon through permafrost thaw (Schuur et al., 2011). While these changes in the greenhouse gas balance of the terrestrial Arctic are described in numerous studies, a connection with a decline in sea ice extent is nonetheless seldom made. In addition to these changes on land, a lower sea ice extent also has a direct effect on the exchange of greenhouse gases between the ocean and the atmosphere. For example, due to sea ice retreat, more ocean surface remains in contact with the atmosphere, and this has been suggested to increase the oceanic uptake of CO2 (Bates et al., 2006). However, the sustainability of this increased uptake is uncertain (Cai et al., 2010), and carbon fluxes related directly to the sea ice itself add much uncertainty to the oceanic uptake of CO2 (Nomura et al., 2006; Rysgaard et al., 2007). Furthermore, significant emissions of methane from the Arctic Ocean have been observed (Kort et al., 2012; Shakhova et al., 2010), but the consequence of a lower sea ice extent thereon is still unclear. Overall, the decline in sea ice that has been seen in recent

  14. Strategic environmental assessment of greenhouse gas mitigation options in the Canadian agricultural sector.

    PubMed

    Noble, Bram F; Christmas, Lisa M

    2008-01-01

    This article presents a methodological framework for strategic environmental assessment (SEA) application. The overall objective is to demonstrate SEA as a systematic and structured policy, plan, and program (PPP) decision support tool. In order to accomplish this objective, a stakeholder-based SEA application to greenhouse gas (GHG) mitigation policy options in Canadian agriculture is presented. Using a mail-out impact assessment exercise, agricultural producers and nonproducers from across the Canadian prairie region were asked to evaluate five competing GHG mitigation options against 13 valued environmental components (VECs). Data were analyzed using multi-criteria and exploratory analytical techniques. The results suggest considerable variation in perceived impacts and GHG mitigation policy preferences, suggesting that a blanket policy approach to GHG mitigation will create gainers and losers based on soil type and associate cropping and on-farm management practices. It is possible to identify a series of regional greenhouse gas mitigation programs that are robust, socially meaningful, and operationally relevant to both agricultural producers and policy decision makers. The assessment demonstrates the ability of SEA to address, in an operational sense, environmental problems that are characterized by conflicting interests and competing objectives and alternatives. A structured and systematic SEA methodology provides the necessary decision support framework for the consideration of impacts, and allows for PPPs to be assessed based on a much broader set of properties, objectives, criteria, and constraints whereas maintaining rigor and accountability in the assessment process.

  15. Graduate training in Earth science across borders and disciplines: ArcTrain -"Processes and impacts of climate change in the North Atlantic Ocean and the Canadian Arctic"

    NASA Astrophysics Data System (ADS)

    Stein, Rüdiger; Kucera, Michal; Walter, Maren; de Vernal, Anne

    2015-04-01

    Due to a complex set of feedback processes collectively known as "polar amplification", the Arctic realm is expected to experience a greater-than-average response to global climate forcing. The cascades of feedback processes that connect the Arctic cryosphere, ocean and atmosphere remain incompletely constrained by observations and theory and are difficult to simulate in climate models. Our capacity to predict the future of the region and assess the impacts of Arctic change processes on global and regional environments hinges on the availability of interdisciplinary experts with strong international experience and understanding of the science/society interface. This is the basis of the International Research Training Group "Processes and impacts of climate change in the North Atlantic Ocean and the Canadian Arctic - ArcTrain", which was initiated in 2013. ArcTrain aims to educate PhD students in an interdisciplinary environment that combines paleoclimatology, physical oceanography, remote sensing and glaciology with comprehensive Earth system modelling, including sea-ice and ice-sheet components. The qualification program for the PhD students includes joint supervision, mandatory research residences at partner institutions, field courses on land and on sea (Floating University), annual meetings and training workshops and a challenging structured training in expert skills and transferrable skills. Its aim is to enhance the career prospects and employability of the graduates in a challenging international job market across academic and applied sectors. ArcTrain is a collaborative project at the University of Bremen and the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven. The German part of the project is designed to continue for nine years and educate three cohorts of twelve PhD students each. The Canadian partners comprise a consortium of eight universities led by the GEOTOP cluster at the Université du Québec à Montréal and including

  16. Physical Mechanisms Controlling Interannual and Seasonal Variations in Melt Pond Evolution on First-Year Sea Ice in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Landy, J.; Ehn, J. K.; Shields, M.; Barber, D. G.

    2014-12-01

    At the transition between spring and summer, melt ponds form and evolve at the surface of Arctic sea ice, significantly modifying energy exchanges between the ice, atmosphere and ocean. Past observations have demonstrated that the fractional coverage of melt ponds on Arctic sea ice can vary widely over the course of a melt season, between years in the same location, and between regions. Here we present two years of melt pond observations from landfast, first-year sea ice in the Canadian Arctic, and analyze which physical mechanisms were responsible for considerable interannual variations in melt pond coverage. In general, the key factors affecting pond coverage were: (1) premelt surface topography, (2) the number of drainage features in the ice and locations of drainage channels, (3) the evolution of ice temperature, and (4) the surface energy balance. Terrestrial LiDAR measurements showed that the premelt topography was rougher in 2011 than in 2012, which led to interannual variations in maximum pond coverage and hydraulic head of 20 pp and 7 cm, respectively. A change in the meltwater balance (production minus drainage) caused the ponds to spread or recede over an area that was almost 90% larger in 2012 than in 2011. The LiDAR measurements also demonstrated that premelt topography was modified due to preferential melting under meltwater drainage channels. Some melt ponds in areas of low-lying premelt topography were unexpectedly drained as the ponds became elevated above deepening channels. Although the sea ice cover was 0.35 m thinner in 2012 than in 2011, ice interior temperatures remained colder later into June, delaying a transition in ice permeability that would allow vertical meltwater drainage from ponds. This permeability transition was observed in 2011 and contributed to a significant drop in pond coverage. For more information see: Landy, J., J. Ehn, M. Shields, and D. Barber (2014), Surface and melt pond evolution on landfast first-year sea ice in the

  17. Tectonic Framework of the Beaufort-Mackenzie Margin, Canadian Arctic Ocean, from Integrated Deep Seismic and Potential-Field Studies

    NASA Astrophysics Data System (ADS)

    Helwig, J. A.; Bird, D. E.; Kumar, N.; Emmet, P. A.; Dinkelman, M.

    2012-12-01

    A five-year long, ION ArcticSPAN seismic survey program in the Canadian Beaufort Sea expands and elaborates the tectonic framework of the Canada Basin passive margin. The margin is clearly subdivided into three segments of different orientation and structure: 1) the overprinted Cordilleran-Beaufort Foldbelt segment trending west towards Alaska; 2) the transtensional Tuk segment trending northeast off the Tuktoyaktuk Peninsula; and 3) the extensional Banks segment trending north off Banks Island. From nearshore to 2500 m depth, over 20,000 km of 2D long-offset data were acquired and processed into 40 km deep PSDM profiles. The latest lines used special technology for shooting beneath first-year ice-covered areas, and 450 km of OBC data were acquired in the nearshore transition zone. From well control in the Mackenzie Delta area, a geological interpretation is extended into the late Jurassic to Recent passive margin stratigraphy as well as the varying underlying crust of both oceanic affinity, and Ellesmerian and Laurentian continental affinities. Major elements of a tectonic synthesis include: 1) deep profiles show the Tertiary detached Beaufort foldbelt overlies greatly extended continental and/or oceanic crust although the COB is obscured by the overprint; 2) oceanic crust with steep relief is found at the inferred junction of the extinct spreading center of the Canada Basin in the Mackenzie delta; 3) on the Tuk margin, thick Proterozoic and Paleozoic strata flanking the Laurentian craton are terminated at the COB by a transform fault system; and 4) architecture of the Banks segment includes late Jurassic rift structure, and a continent-ocean transition beneath the continental slope prism that includes gravitational folds down-dip of shallower extensional break-away faults and rollover folds in the Tertiary. Our tectonic framework is consistent with a rotational model for opening of the Canada Basin. The free air gravity field is dominated by a high

  18. Polarimetric C-/X-band Synthetic Aperture Radar Observations of Melting Sea Ice in the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Casey, J. A.; Beckers, J. F.; Brossier, E.; Haas, C.

    2013-12-01

    Operational ice information services rely heavily on space-borne synthetic aperture radar (SAR) data for the production of ice charts to meet their mandate of providing timely and accurate sea ice information to support safe and efficient marine operations. During the summer melt period, the usefulness of SAR data for sea ice monitoring is limited by the presence of wet snow and melt ponds on the ice surface, which can mask the signature of the underlying ice. This is a critical concern for ice services whose clients (e.g. commercial shipping, cruise tourism, resource exploration and extraction) are most active at this time of year when sea ice is at its minimum extent, concentration and thickness. As a result, there is a need to further quantify the loss of ice information in SAR data during the melt season and to identify what information can still be retrieved about ice surface conditions and melt pond evolution at this time of year. To date the majority of studies have been limited to analysis of single-polarization C-band SAR data. This study will investigate the potential complimentary and unique sea ice information that polarimetric C- and X-band SAR data can provide to supplement the information available from traditional single co-polarized C-band SAR data. A time-series of polarimetric C- and X-band SAR data was acquired over Jones Sound in the Canadian Arctic Archipelago, in the vicinity of the Grise Fiord, Nunavut. Five RADARSAT-2 Wide Fine Quad-pol images and 11 TerraSAR-X StripMap dual-pol (HH/VV) images were acquired. The time-series begins at the onset of melt in early June and extends through advanced melt conditions in late July. Over this period several ponding and drainage events and two snowfall events occurred. Field observations of sea ice properties were collected using an Ice Mass Balance (IMB) buoy, hourly photos from a time-lapse camera deployed on a coastal cliff, and manual in situ measurements of snow thickness and melt pond depth

  19. Holocene History of the Bering Sea Bowhead Whale ( Balaena mysticetus) in Its Beaufort Sea Summer Grounds off Southwestern Victoria Island, Western Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Dyke, Arthur S.; Savelle, James M.

    2001-05-01

    The fossil remains of 43 bowhead whales were mapped on the raised beaches of western Wollaston Peninsula, Victoria Island, Canadian Arctic, near the historic summer range limit of the Bering Sea stock in the Beaufort Sea. The elevations and radiocarbon ages of the remains demonstrate that the bowhead ranged commonly into the region following the submergence of Bering Strait at ca. 10,000 14C yr B.P. until ca. 8500 14C yr B.P. During the same interval, bowheads ranged widely from the Beaufort Sea to Baffin Bay. Subsequently, no whales reached Wollaston Peninsula until ca. 1500 14C yr B.P. Late Holocene populations evidently were small, or occupations were brief, in comparison to those of the early Holocene. Although the late Holocene recurrence may relate to the expansion of pioneering Thule whalers eastward from Alaska, there are few Thule sites and limited evidence of Thule whaling in the area surveyed to support this suggestion.

  20. Shifts in biological productivity inferred from nutrient drawdown in the southern Beaufort Sea (2003-2011) and northern Baffin Bay (1997-2011), Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Bergeron, Myriam; Tremblay, Jean-Éric

    2014-06-01

    This paper reports the first in situ evidence of change in the net biological productivity of high-latitude western Arctic seas. Estimates of seasonal drawdown for major plant nutrients show that net community production (NCP) shifted differently in two contrasted Canadian oceanographic settings. In the stratified southeast Beaufort Sea, seasonal nitrate consumption increased 1.6-fold between 2003-2004 and 2010-2011. The concomitant thickening of the nitrate-depleted layer in summer/fall implies that subsurface chlorophyll maxima now consume nutrients over a larger extent of the water column. Meanwhile, nitrate consumption in the once productive North Water Polynya declined by 65% and is now nearly on par with the oligotrophic coastal Beaufort Sea. This decline is attributed to freshening and increased stratification. Commensurate changes in silicate and phosphate drawdown in the two regions indicate that diatoms drove the spatial and temporal shifts in NCP.

  1. A regional approach to plant DNA barcoding provides high species resolution of sedges (Carex and Kobresia, Cyperaceae) in the Canadian Arctic Archipelago.

    PubMed

    Clerc-Blain, Jessica L E; Starr, Julian R; Bull, Roger D; Saarela, Jeffery M

    2010-01-01

    Previous research on barcoding sedges (Carex) suggested that basic searches within a global barcoding database would probably not resolve more than 60% of the world's some 2000 species. In this study, we take an alternative approach and explore the performance of plant DNA barcoding in the Carex lineage from an explicitly regional perspective. We characterize the utility of a subset of the proposed protein-coding and noncoding plastid barcoding regions (matK, rpoB, rpoC1, rbcL, atpF-atpH, psbK-psbI) for distinguishing species of Carex and Kobresia in the Canadian Arctic Archipelago, a clearly defined eco-geographical region representing 1% of the Earth's landmass. Our results show that matK resolves the greatest number of species of any single-locus (95%), and when combined in a two-locus barcode, it provides 100% species resolution in all but one combination (matK + atpFH) during unweighted pair-group method with arithmetic mean averages (UPGMA) analyses. Noncoding regions were equally or more variable than matK, but as single markers they resolve substantially fewer taxa than matK alone. When difficulties with sequencing and alignment due to microstructural variation in noncoding regions are also considered, our results support other studies in suggesting that protein-coding regions are more practical as barcoding markers. Plastid DNA barcodes are an effective identification tool for species of Carex and Kobresia in the Canadian Arctic Archipelago, a region where the number of co-existing closely related species is limited. We suggest that if a regional approach to plant DNA barcoding was applied on a global scale, it could provide a solution to the generally poor species resolution seen in previous barcoding studies.

  2. Integration of New Observation Techniques, Remote Sensing, and High Resolution Modelling for Improved Quantification of Rapid Environmental Change at a Canadian Arctic Watershed

    NASA Astrophysics Data System (ADS)

    Marsh, P.; Toure, A.; Baltzer, J. L.; Sonnentag, O.; Berg, A. A.; Derksen, C.; Walker, B.; Wilcox, E.

    2016-12-01

    Multi-decade observations at a research watershed in the western Canadian Arctic has demonstrated rapid environmental change, but has also shown that our quantification of, and understanding of, these changes is greatly limited by both the large errors involved in many observation data sets and the limitations of standard models to operate at the extremely high resolution required. This paper will outline an expanding research program being developed at the Trail Valley Creek research watershed south of Tuktoyaktuk, NWT with the gaol to overcome these limitations. Although this watershed has existing high quality observations, the following example will illustrate the challenges faced in understanding the ongoing changes. As might be expected, the climate at this location is dramatically warming, but it is also drying, and the active layer is deepening, shrub patches are both infilling and expanding, the end of winter snow cover is expanding in shrub patches and possibly decreasing in slope drifts, and snowmelt rate is changing. However, the resulting decrease in streamflow and delayed melt runoff, is unexpected and hard to explain. Although we can postulate why these changes are occurring, the observations at this site, among the best in the Canadian Arctic, are not sufficient to allow us to fully explain the ongoing changes. Our experience at Trail Valley Creek suggests that in order to improve our understanding and predictive ability, we need enhanced field observations and models. This paper will outline how we are developing such a program at Trail Valley Creek with field observations across a range of scales (a network of cosmic ray sensors, eddy covariance measurements, and sap flow sensors for example); enhanced remote sensing using lidar, optical and radar methods from Unmanned Aerial Systems, aircraft and satellites; and high resolution, physics based, snow, permafrost and hydrologic models.

  3. Temporal trends of PBDEs and emerging flame retardants in belugas from the St. Lawrence Estuary (Canada) and comparisons with minke whales and Canadian Arctic belugas.

    PubMed

    Simond, Antoine E; Houde, Magali; Lesage, Véronique; Verreault, Jonathan

    2017-07-01

    An exponential level increase of the ubiquitous halogenated flame retardant (HFR) class polybrominated diphenyl ether (PBDE) has been documented during the 1990s in endangered belugas (Delphinapterus leucas) from the St. Lawrence Estuary (SLE), Eastern Canada. The recent worldwide bans and regulations of PBDE mixtures led to their replacement by alternative HFRs (so-called emerging HFRs) that are increasingly being reported in various environmental compartments. There are, however, limited knowledge on the spatial and temporal trends of PBDEs and emerging HFRs in cetaceans, especially after restrictions on PBDE usage. The first objective of this study was to investigate the occurrence of HFRs (35 PBDE congeners and 13 emerging compounds) in the blubber of belugas and minke whales (Balænoptera acutorostrata) found dead in the Estuary or Gulf of St. Lawrence as well as belugas from Nunavik (Canadian Arctic) collected as part of the Inuit subsistence hunt. A second objective was to investigate the trends of HFR concentrations in SLE beluga males between 1997 and 2013. PBDEs were the most abundant HFRs in all three whale populations, while hexabromobenzene (HBB), Chlordene Plus (CPlus), Dechlorane Plus (DP), and Dechlorane 604 Component B (Dec-604 CB) were quantified in the majority of blubber samples. Overall, concentrations of emerging HFRs were notably greater in SLE belugas compared to the two other whale populations, with the exception of DP and Dec-604 CB that were found in greater concentrations in Canadian Arctic belugas. No significant trend in blubber PBDE concentrations was found in SLE belugas during this 17-year period. This suggests that global PBDE regulations are too recent to observe changes in PBDE concentrations in belugas from this highly HFR-exposed environment. In contrast, concentrations of HBB and CPlus in SLE belugas decreased slightly from 1997 to 2013, while DP increased up until 2000 and decreased slightly thereafter. The occurrence and

  4. Application of Terrestrial Ecosystem Monitoring under the CAFF Circumpolar Biodiversity Monitoring Program: Designing and Implementing Terrestrial Monitoring to Establish the Canadian High Arctic Research Station as a Flagship Arctic Environmental Monitoring Site

    NASA Astrophysics Data System (ADS)

    McLennan, D.; Kehler, D.

    2016-12-01

    The Canadian High Arctic Research Station (CHARS) is scheduled for completion in July 2017 and is the northern science component of Polar Knowledge Canada (POLAR). A mandated goal for POLAR is to establish the adjacent Experimental and Reference Area (ERA) as an Arctic Flagship monitoring site that will track change in Arctic terrestrial, freshwater and marine ecosystems. Situated in the community of Cambridge Bay, CHARS provides the opportunity to draw on the Indigenous Knowledge of local residents to help design and conduct the monitoring, and to operate 12 months a year. Monitoring at CHARS will be linked to networks nationally and internationally, and is being designed so that change in key indicators can be understood in terms of drivers and processes, modeled and scaled up regionally, and used to predict important changes in critical indicators. As a partner in the Circumpolar Biodiversity Monitoring Program (CBMP), the monitoring design for terrestrial ecosystems follows approaches outlined by the CBMP Terrestrial Expert Monitoring Group, who have listed key monitoring questions and identified a list of important Focal Ecosystem Components (FECs). To link drivers to FECs we are proposing a multi-scaled approach: 1) an Intensive Monitoring Area to establish replicated monitoring plots that track change in snow depth and condition, active layer depth, soil temperature, soil moisture, and soil solution chemistry that are spatially and temporally linked to changes in microbiological activity, CO2/CH4 net ecosystem flux, vegetation relative frequency, species composition, growth and foliar nutrient concentration, arthropod abundance, lemming abundance and health, and shorebird/songbird abundance and productivity. 2) These intensive observations are supported by watershed scale measures that will monitor, during the growing season, lemming winter nest abundance, songbird, shorebird and waterfowl staging and nesting, and other observations; in the winter we will

  5. Longer ice-free seasons increase the risk of nest depredation by polar bears for colonial breeding birds in the Canadian Arctic.

    PubMed

    Iverson, Samuel A; Gilchrist, H Grant; Smith, Paul A; Gaston, Anthony J; Forbes, Mark R

    2014-03-22

    Northern polar regions have warmed more than other parts of the globe potentially amplifying the effects of climate change on biological communities. Ice-free seasons are becoming longer in many areas, which has reduced the time available to polar bears (Ursus maritimus) to hunt for seals and hampered bears' ability to meet their energetic demands. In this study, we examined polar bears' use of an ancillary prey resource, eggs of colonial nesting birds, in relation to diminishing sea ice coverage in a low latitude region of the Canadian Arctic. Long-term monitoring reveals that bear incursions onto common eider (Somateria mollissima) and thick-billed murre (Uria lomvia) nesting colonies have increased greater than sevenfold since the 1980s and that there is an inverse correlation between ice season length and bear presence. In surveys encompassing more than 1000 km of coastline during years of record low ice coverage (2010-2012), we encountered bears or bear sign on 34% of eider colonies and estimated greater egg loss as a consequence of depredation by bears than by more customary nest predators, such as foxes and gulls. Our findings demonstrate how changes in abiotic conditions caused by climate change have altered predator-prey dynamics and are leading to cascading ecological impacts in Arctic ecosystems.

  6. Longer ice-free seasons increase the risk of nest depredation by polar bears for colonial breeding birds in the Canadian Arctic

    PubMed Central

    Iverson, Samuel A.; Gilchrist, H. Grant; Smith, Paul A.; Gaston, Anthony J.; Forbes, Mark R.

    2014-01-01

    Northern polar regions have warmed more than other parts of the globe potentially amplifying the effects of climate change on biological communities. Ice-free seasons are becoming longer in many areas, which has reduced the time available to polar bears (Ursus maritimus) to hunt for seals and hampered bears’ ability to meet their energetic demands. In this study, we examined polar bears’ use of an ancillary prey resource, eggs of colonial nesting birds, in relation to diminishing sea ice coverage in a low latitude region of the Canadian Arctic. Long-term monitoring reveals that bear incursions onto common eider (Somateria mollissima) and thick-billed murre (Uria lomvia) nesting colonies have increased greater than sevenfold since the 1980s and that there is an inverse correlation between ice season length and bear presence. In surveys encompassing more than 1000 km of coastline during years of record low ice coverage (2010–2012), we encountered bears or bear sign on 34% of eider colonies and estimated greater egg loss as a consequence of depredation by bears than by more customary nest predators, such as foxes and gulls. Our findings demonstrate how changes in abiotic conditions caused by climate change have altered predator–prey dynamics and are leading to cascading ecological impacts in Arctic ecosystems. PMID:24500172

  7. Studies of the Canadian Arctic Archipelago water transport and its relationship to basin-local forcings: Results from AO-FVCOM

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Chen, Changsheng; Beardsley, Robert C.; Gao, Guoping; Lai, Zhigang; Curry, Beth; Lee, Craig M.; Lin, Huichan; Qi, Jianhua; Xu, Qichun

    2016-06-01

    A high-resolution (up to 2 km), unstructured-grid, fully coupled Arctic sea ice-ocean Finite-Volume Community Ocean Model (AO-FVCOM) was employed to simulate the flow and transport through the Canadian Arctic Archipelago (CAA) over the period 1978-2013. The model-simulated CAA outflow flux was in reasonable agreement with the flux estimated based on measurements across Davis Strait, Nares Strait, Lancaster Sound, and Jones Sounds. The model was capable of reproducing the observed interannual variability in Davis Strait and Lancaster Sound. The simulated CAA outflow transport was highly correlated with the along-strait and cross-strait sea surface height (SSH) difference. Compared with the wind forcing, the sea level pressure (SLP) played a dominant role in establishing the SSH difference and the correlation of the CAA outflow with the cross-strait SSH difference can be explained by a simple geostrophic balance. The change in the simulated CAA outflow transport through Davis Strait showed a negative correlation with the net flux through Fram Strait. This correlation was related to the variation of the spatial distribution and intensity of the slope current over the Beaufort Sea and Greenland shelves. The different basin-scale surface forcings can increase the model uncertainty in the CAA outflow flux up to 15%. The daily adjustment of the model elevation to the satellite-derived SSH in the North Atlantic region outside Fram Strait could produce a larger North Atlantic inflow through west Svalbard and weaken the outflow from the Arctic Ocean through east Greenland.

  8. A trajectory analysis of atmospheric transport of black carbon aerosols to Canadian High Arctic in winter and spring (1990-2005)

    NASA Astrophysics Data System (ADS)

    Huang, L.; Gong, S. L.; Sharma, S.; Lavoué, D.; Jia, C. Q.

    2010-02-01

    Black carbon (BC) particles accumulated in the Arctic troposphere and deposited over snow have significant effects on radiative forcing of the Arctic regional climate. Applying cluster analysis technique on 10-day backward trajectories, transport pathways affecting Alert (82.5° N, 62.5° W), Nunavut in Canada are identified in this work, along with the associated transport frequency. Based on the atmospheric transport frequency and the estimated BC emission intensity from surrounding regions, a linear regression model is constructed to investigate the inter-annual variations of BC observed at Alert in January and April, representative of winter and spring respectively, between 1990 and 2005. Strong correlations are found between BC concentrations predicted with the regression model and measured at Alert for both seasons (R2 equals 0.77 and 0.81 for winter and spring, respectively). Results imply that atmospheric transport and BC emission are the major contributors to the inter-annual variations in BC concentrations observed at Alert in the cold seasons for the 16-year period. Based on the regression model the relative contributions of regional BC emissions affecting Alert are attributed to the Eurasian sector, composed of the European Union and the former USSR, and the North American sector. Considering both seasons, the model suggests that Eurasia is the major contributor to the near-surface BC levels at the Canadian High Arctic site with an average contribution of over 85% during the 16-year period. In winter, the atmospheric transport of BC aerosols from Eurasia is found to be even more predominant with a multi-year average of 94%. The model estimates smaller contribution from the Eurasian sector in spring (70%) than that in winter. It is also found that the change in Eurasian contributions depends mainly on the reduction of emission intensity, while the changes in both emission and atmospheric transport contributed to the inter-annual variation of North

  9. Application of well data in oil and gas assessment - Arctic National Wildlife Refuge

    USGS Publications Warehouse

    Nelson, Philip H.; Schenk, Christopher J.; Bird, Kenneth J.

    1998-01-01

    A current assessment of oil and gas resources in the Arctic National Wildlife Refuge 1002 area by the U.S. Geological Survey relies upon seismic data, geological mapping of exposures south and west of the assessment area and exploratory wells. Well data assembled for the 41 wells include: well logs, core descriptions and measurements, formation tops, biostratigraphic boundaries, drill-stem tests, casing points, fission-track age dates, vitrinite reflectance, and organic-carbon content. These data are used in the synthesis of all available data and presentation on a well-by-well basis, and extraction of volumetric parameters that are used to assess undiscovered accumulations.

  10. Large herbivore grazing affects the vegetation structure and greenhouse gas balance in a high arctic mire

    NASA Astrophysics Data System (ADS)

    Falk, Julie Maria; Schmidt, Niels Martin; Christensen, Torben R.; Ström, Lena

    2015-04-01

    Herbivory is an important part of most ecosystems and affects the ecosystems’ carbon balance both directly and indirectly. Little is known about herbivory and its impact on the carbon balance in high arctic mire ecosystems. We hypothesized that trampling and grazing by large herbivores influences the vegetation density and composition and thereby also the carbon balance. In 2010, we established fenced exclosures in high arctic Greenland to prevent muskoxen (Ovibos moschatus) from grazing. During the growing seasons of 2011 to 2013 we measured CO2 and CH4 fluxes in these ungrazed blocks and compared them to blocks subjected to natural grazing. Additionally, we measured depth of the water table and active layer, soil temperature, and in 2011 and 2013 an inventory of the vegetation density and composition were made. In 2013 a significant decrease in total number of vascular plant (33-44%) and Eriophorum scheuchzeri (51-53%) tillers were found in ungrazed plots, the moss-layer and amount of litter had also increased substantially in these plots. This resulted in a significant decrease in net ecosystem uptake of CO2 (47%) and likewise a decrease in CH4 emission (44%) in ungrazed plots in 2013. While the future of the muskoxen in a changing arctic is unknown, this experiment points to a potentially large effect of large herbivores on the carbon balance in natural Arctic ecosystems. It thus sheds light on the importance of grazing mammals, and hence adds to our understanding of natural ecosystem greenhouse gas balance in the past and in the future.

  11. Enhanced sea-ice export from the Arctic to the GIN seas during the Younger Dryas: A "Canadian" source from radiogenic isotope signatures

    NASA Astrophysics Data System (ADS)

    Hillaire-Marcel, C.; Maccali, J.; Not, C.; Poirier, A.

    2012-04-01

    The Younger Dryas (YD) cooling event and the related slowing of the Atlantic Meridional Overturning Circulation (AMOC) have been linked to a large array of processes. The most widely supported causal mechanism involves an influx of freshwater into the North Atlantic Ocean linked to a partial drainage of glacial Lake Agassiz. Recently, a northward drainage route, through the Mackenzie River outlet into the Arctic Ocean, has been suggested from land-based studies [Murton et al., Nature 464, 740-743]. Sedimentological and geochemical analysis of cores raised from Lomonosov Ridge and the Fram Strait area, yield relatively robust evidence for enhanced ice-rafting deposition -IRD- (with a 5-fold increase -) during the critical interval. At Lomonosov, the corresponding sedimentary layer (from ca. 13 to 12 ka) is marked by a pulse of detrital carbonates in the silt to sand fractions, with approximately equal amounts of calcite and dolomite, pointing towards an Arctic Canadian sediment source area [Not & Hillaire-Marcel, Nature Communication, Jan. 31, 2012]. The layer also depicts a 5 fold increase 230Th-excess, which we link to an enhanced flux of scavenging particles. At both sites, the geochemical signatures of the YD-layer, based on elemental (Zr/Al) and isotopic (Sr, Nd and Pb) data on bulk sediments and residues ensuing from the removal of exchangeable fractions (Zr/Al, Nd, Pb, Sr), are used to identify detrital sediment source areas. Whereas three major source areas variably contributed to IRD during the MIS 3-Present interval (i.e., the Russian, Canadian and Greenland margins), the YD interval singles out by strongelemental and isotopic excursions, notably a peak in radiogenic Sr, indicating prominent supplies from the Canadian end-member. This suggests enhanced sea-ice production and drifting along the BeaufordGyre, then the Trans-Polar Drift. A major drainage event along the Mackenzie outlet area, as proposed in the above reference,would be a suitable trigger for

  12. The Canadian experience in frontier environmental protection

    SciTech Connect

    Jones, G.H. )

    1991-03-01

    Early Canadian frontier exploration (from 1955 onshore and from 1966 for offshore drilling) caused insignificant public concern. The 1967-1968 Torrey Canyon Tanker and Santa Barbara disasters roused public opinion and governments. In Canada, 1969-1970 Arctic gas blowouts, a tanker disaster, and damage to the 'Manhattan' exacerbated concerns and resulted in new environmental regulatory constraints. From 1970, the Arctic Petroleum Operations Association learned to operate safely with environmental responsibility. It studied physical environment for design criteria, and the biological and human environment to ameliorate impact. APOA's research projects covered sea-ice, permafrost, sea-bottom, oil-spills, bird and mammal migration, fish habitat, food chains, oceanography, meteorology, hunters'/trappers' harvests, etc. In 1971 Eastcoast Petroleum Operators' Association and Alaska Oil and Gas Association followed APOA's cooperative research model. EPOA stressed icebergs and fisheries. Certain research was handled by the Canadian Offshore Oil Spill Research Association. By the mid-1980s these associations had undertaken $70,000,000 of environmental oriented research, with equivalent additional work by member companies on specific needs and similar sums by Federal agencies often working with industry on complementary research. The frontier associations then merged with the Canadian Petroleum Association, already active environmentally in western Canada. Working with government and informing environmental interest groups, the public, natives, and local groups, most Canadian frontier petroleum operations proceeded with minimal delay and environmental disturbance.

  13. Effect of Submarine Groundwater Discharge on Relict Arctic Submarine Permafrost and Gas Hydrate

    NASA Astrophysics Data System (ADS)

    Frederick, J. M.; Buffett, B. A.

    2014-12-01

    Permafrost-associated gas hydrate deposits exist at shallow depths within the sediments of the circum-Arctic continental shelves. Degradation of this shallow water reservoir has the potential to release large quantities of methane gas directly to the atmosphere. Gas hydrate stability and the permeability of the shelf sediments to gas migration is closely linked with submarine permafrost. Submarine permafrost extent depends on several factors, such as the lithology, sea level variations, mean annual air temperature, ocean bottom water temperature, geothermal heat flux, and the salinity of the pore water. The salinity of the pore water is especially relevant because it partially controls the freezing point for both ice and gas hydrate. Measurements of deep pore water salinity are few and far between, but show that deep off-shore sediments are fresh. Deep freshening has been attributed to large-scale topographically-driven submarine groundwater discharge, which introduces fresh terrestrial groundwater into deep marine sediments. We investigate the role of submarine ground water discharge on the salinity field and its effects on the seaward extent of relict submarine permafrost and gas hydrate stability on the Arctic shelf with a 2D shelf-scale model based on the finite volume method. The model tracks the evolution of the temperature, salinity, and pressure fields given imposed boundary conditions, with latent heat of water ice and hydrate formation included. The permeability structure of the sediments is coupled to changes in permafrost. Results show that pore fluid is strongly influenced by the permeability variations imposed by the overlying permafrost layer. Groundwater discharge tends to travel horizontally off-shore beneath the permafrost layer and the freshwater-saltwater interface location displays long timescale transient behavior that is dependent on the groundwater discharge strength. The seaward permafrost extent is in turn strongly influenced by the

  14. Canadian Unilateralism in the Arctic: Using Scenario Planning to Help Canada Achieve Its Strategic Goals in the North

    DTIC Science & Technology

    2013-05-23

    in the North Approved by: , Monograph Director Michael D. Mihalka, Ph.D. , Seminar Leader Gordon A. Richardson, COL...Ice," in Arctic Report Card 2012, ed. M. O. Jeffries, J. A. Richter-Menge, and J. E . Overland (Washington: NOAA, 2012): 39, http...Stakes, 4. 15 Cooperation Dr. Michael Byers holds a Canada Research Chair in Global

  15. Arctic summary report: Outer Continental Shelf oil and gas activities in the Arctic and their onshore impacts

    NASA Astrophysics Data System (ADS)

    Lynch, C.; Slitor, D. L.; Rudolph, R. W.

    1985-01-01

    Issues and developments occuring in the Arctic Outer Continental Shelf subregion are discussed. The geology and hydrocarbon potential of the Diapir Field petroleum provinces are detailed. Recent lease sales, exploration activities, and the first development proposals for offshore areas of the North slope are considered. Issues relating to transporting resources from production islands to shore and various proposals for moving Arctic hydrocarbons to market are presented. Production projects onshore and possible support bases for offshore activity are also examined.

  16. North America Arctic report

    SciTech Connect

    Williams, B.

    1982-07-12

    This work covers exploration and development action and plans in the Arctic frontiers of the US and Canada. An update is provided of the status and outlook in the Arctic islands, off the Canadian East Coast, in the Canadian-US Beaufort Sea, and in Alaska's onshore and offshore areas. How operators plan to delay the invitable decline and maintain production at Prudhoe Bay also is discussed.

  17. Air-sea CO2 and CH4 gas transfer velocity in Arctic sea-ice regions from eddy covariance flux measurements onboard Icebreaker Oden

    NASA Astrophysics Data System (ADS)

    Prytherch, John; Brooks, Ian; Crill, Patrick; Thornton, Brett; Salisbury, Dominic; Tjernström, Michael; Anderson, Leif; Geibel, Marc; Humborg, Christoph

    2017-04-01

    The Arctic Ocean is an important sink for atmospheric CO2, and there is ongoing debate on whether seafloor seeps in the Arctic are a large source of CH4 to the atmosphere. The impact of warming waters, decreasing sea-ice extent and expanding marginal ice zones on Arctic air-sea gas exchange depends on the rate of gas transfer in the presence of sea ice. Sea ice acts as a near-impermeable lid to air-sea gas exchange, but is also hypothesised to enhance gas transfer rates through physical processes such as increased surface-ocean turbulence from ice-water shear and ice-edge form drag. The dependence of the gas transfer rate on sea-ice concentration remains uncertain due to a lack of in situ measurements. Here we present the first direct estimates of gas transfer rate in a wide range of Arctic sea-ice conditions. The estimates were derived from eddy covariance CO2 and CH4 fluxes, measured from the Swedish Icebreaker Oden during two expeditions: the 3-month duration Arctic Clouds in Summer Experiment (ACSE) in 2014, a component of the Swedish-Russian-US Arctic Ocean Investigation on Climate-Cryosphere-Carbon Interactions (SWERUS-C3) in the eastern Arctic Ocean shelf region; and the Arctic Ocean 2016 expedition to the high latitude Arctic Ocean. Initial CO2 results from ACSE showed that the gas transfer rate has a near-linear dependence on sea-ice concentration, and that some previous indirect measurements and modelling estimates overestimate gas transfer rates in sea-ice regions. This supports a linear sea-ice scaling approach for assessments of polar ocean carbon fluxes. Air-sea gas transfer model assumptions (e.g. Schmidt number dependence) will be examined using simultaneous CO2 and CH4 measurements, and observations in different ice conditions (e.g. summer melt, autumn freeze up, central Arctic and marginal ice zones) will be compared.

  18. Contribution of oceanic gas hydrate dissociation to the formation of Arctic Ocean methane plumes

    SciTech Connect

    Reagan, M.; Moridis, G.; Elliott, S.; Maltrud, M.

    2011-06-01

    Vast quantities of methane are trapped in oceanic hydrate deposits, and there is concern that a rise in the ocean temperature will induce dissociation of these hydrate accumulations, potentially releasing large amounts of carbon into the atmosphere. Because methane is a powerful greenhouse gas, such a release could have dramatic climatic consequences. The recent discovery of active methane gas venting along the landward limit of the gas hydrate stability zone (GHSZ) on the shallow continental slope (150 m - 400 m) west of Svalbard suggests that this process may already have begun, but the source of the methane has not yet been determined. This study performs 2-D simulations of hydrate dissociation in conditions representative of the Arctic Ocean margin to assess whether such hydrates could contribute to the observed gas release. The results show that shallow, low-saturation hydrate deposits, if subjected to recently observed or future predicted temperature changes at the seafloor, can release quantities of methane at the magnitudes similar to what has been observed, and that the releases will be localized near the landward limit of the GHSZ. Both gradual and rapid warming is simulated, along with a parametric sensitivity analysis, and localized gas release is observed for most of the cases. These results resemble the recently published observations and strongly suggest that hydrate dissociation and methane release as a result of climate change may be a real phenomenon, that it could occur on decadal timescales, and that it already may be occurring.

  19. Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming

    PubMed Central

    Hong, Wei-Li; Torres, Marta E.; Carroll, JoLynn; Crémière, Antoine; Panieri, Giuliana; Yao, Haoyi; Serov, Pavel

    2017-01-01

    Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of Spitsbergen (Storfjordrenna, ∼380 m water depth). Modelling of the non-steady-state porewater profiles and observations of distinct layers of methane-derived authigenic carbonate nodules in the sediments indicate centurial to millennial methane emissions in the region. Results of temperature modelling suggest limited impact of short-term warming on gas hydrates deeper than a few metres in the sediments. We conclude that the ongoing and past methane emission episodes at the investigated sites are likely due to the episodic ventilation of deep reservoirs rather than warming-induced gas hydrate dissociation in this shallow water seep site. PMID:28589962

  20. Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming

    DOE PAGES

    Hong, Wei-Li; Torres, Marta E.; Carroll, JoLynn; ...

    2017-06-07

    Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of Spitsbergen (Storfjordrenna, ~380m water depth). Modelling of the non-steady-state porewater profiles and observations of distinct layers of methane-derived authigenic carbonate nodules in the sediments indicate centurial to millennial methane emissions in the region. The results of temperature modelling suggest limited impact ofmore » short-term warming on gas hydrates deeper than a few metres in the sediments. We conclude that the ongoing and past methane emission episodes at the investigated sites are likely due to the episodic ventilation of deep reservoirs rather than warming-induced gas hydrate dissociation in this shallow water seep site.« less

  1. Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming.

    PubMed

    Hong, Wei-Li; Torres, Marta E; Carroll, JoLynn; Crémière, Antoine; Panieri, Giuliana; Yao, Haoyi; Serov, Pavel

    2017-06-07

    Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of Spitsbergen (Storfjordrenna, ∼380 m water depth). Modelling of the non-steady-state porewater profiles and observations of distinct layers of methane-derived authigenic carbonate nodules in the sediments indicate centurial to millennial methane emissions in the region. Results of temperature modelling suggest limited impact of short-term warming on gas hydrates deeper than a few metres in the sediments. We conclude that the ongoing and past methane emission episodes at the investigated sites are likely due to the episodic ventilation of deep reservoirs rather than warming-induced gas hydrate dissociation in this shallow water seep site.

  2. Evidence for bacterially generated hydrocarbon gas in Canadian shield and fennoscandian shield rocks

    NASA Astrophysics Data System (ADS)

    Sherwood Lollar, B.; Frape, S. K.; Fritz, P.; Macko, S. A.; Welhan, J. A.; Blomqvist, R.; Lahermo, P. W.

    1993-12-01

    Hydrocarbon-rich gases found in crystalline rocks on the Canadian and Fennoscandian shields are isotopically and compositionally similar, suggesting that such gases are a characteristic feature of Precambrian Shield rocks. Gases occure in association with saline groundwaters and brines in pressurized "pockets" formed by sealed fracture systems within the host rocks. When released by drilling activities, gas pressures as high as 5000 kPa have been recorded. Typical gas flow rates for individual boreholes range from 0.25 L/min to 4 L/min. The highest concentrations of CH 4 are found in the deepest levels of the boreholes associated with CaNaCl (and NaCaCl) brines. N 2 is the second major component of the gases and with CH 4 accounts for up to 80 to >90 vol%. Higher hydrocarbon (C 2+) concentrations range from <1 to 10 vol.%, with C1/(C2 = C3) ratios from 10-1000. Isotopically the gases show a wide range of values overall ( σ 13C = -57.5 to -41.1%; σ D = -245 to -470‰ ) but a relatively tight cluster of values within each sampling locality. The Enonkoski Mine methanes are unique with σ 13C values between -65.4 and -67.3‰ and σD values between -297 and -347‰. The shield gases are not readily reconcilable with conventional theories of methanogenesis. The range of C1/(C2 + C3) ratios for the shield gases is too low to be consistent with an entirely bacterial origin. In addition, σD CH 4 values are in general too depleted in the heavy isotope to be produced by thermogenic methanogenesis or by secondary alteration processes such as bacterial oxidation or migration. However, isotopic and compositional evidence indicates that bacterially derived gas can account for a significant component of the gas at all shield sites. Conventional bacterial gas accounts for 75-94 vol% of the occurrences at Enonkoski Mine in Finland. At each of the other shield sites, bacterial gas can account for up to 30-50 vol% of the total gas accumulation. This study and other

  3. Critical challenges in ERP implementation: A qualitative case study in the Canadian oil and gas industry

    NASA Astrophysics Data System (ADS)

    Menon, Sreekumar A.

    This exploratory qualitative single-case study examines critical challenges encountered during ERP implementation based on individual perspectives in four project roles: senior leaders, project managers, project team members, and business users, all specifically in Canadian oil and gas industry. Data was collected by interviewing participants belonging to these categories, and by analyzing project documentation about ERP implementation. The organization for the case study was a leading multinational oil and gas company having a substantial presence in the energy sector in Canada. The study results were aligned with the six management questions regarding critical challenges in ERP: (a) circumstances to implement ERP, (b) benefits and process improvements achieved, (c) best practices implemented, (d) critical challenges encountered, (e) strategies and mitigating actions used, and (f) recommendations to improve future ERP implementations. The study results highlight six key findings. First, the study provided valid circumstances for implementing ERP systems. Second, the study underscored the importance of benefits and process improvements in ERP implementation. Third, the study highlighted that adoption of best practices is crucial for ERP Implementation. Fourth, the study found that critical challenges are encountered in ERP Implementation and are significant during ERP implementation. Fifth, the study found that strategies and mitigating actions can overcome challenges in ERP implementation. Finally, the study provided ten major recommendations on how to improve future ERP implementations.

  4. Baseline Monitoring of the Western Arctic Ocean Estimates 20% of Canadian Basin Surface Waters Are Undersaturated with Respect to Aragonite

    PubMed Central

    Robbins, Lisa L.; Wynn, Jonathan G.; Lisle, John T.; Yates, Kimberly K.; Knorr, Paul O.; Byrne, Robert H.; Liu, Xuewu; Patsavas, Mark C.; Azetsu-Scott, Kumiko; Takahashi, Taro

    2013-01-01

    Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index) for the western Arctic Ocean. This data set documents aragonite undersaturation in ∼20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean’s largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater. PMID:24040074

  5. Baseline monitoring of the western Arctic Ocean estimates 20% of Canadian basin surface waters are undersaturated with respect to aragonite.

    PubMed

    Robbins, Lisa L; Wynn, Jonathan G; Lisle, John T; Yates, Kimberly K; Knorr, Paul O; Byrne, Robert H; Liu, Xuewu; Patsavas, Mark C; Azetsu-Scott, Kumiko; Takahashi, Taro

    2013-01-01

    Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index) for the western Arctic Ocean. This data set documents aragonite undersaturation in ≈ 20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean's largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater.

  6. Importance of open marine waters to the enrichment of total mercury and monomethylmercury in lichens in the Canadian High Arctic.

    PubMed

    St Pierre, K A; St Louis, V L; Kirk, J L; Lehnherr, I; Wang, S; La Farge, C

    2015-05-19

    Caribou, which rely on lichens as forage, are a dietary source of monomethylmercury (MMHg) to many of Canada's Arctic Aboriginal people. However, little is understood about the sources of MMHg to lichens in the High Arctic. We quantified MMHg, total mercury (THg) and other chemical parameters (e.g., marine and crustal elements, δ(13)C, δ(15)N, organic carbon, calcium carbonate) in lichen and soil samples collected along transects extending from the coast on Bathurst and Devon islands, Nunavut, to determine factors driving lichen MMHg and THg concentrations in the High Arctic. Lichen MMHg and THg concentrations ranged from 1.41 to 17.1 ng g(-1) and from 36.0 to 361 ng g(-1), respectively. Both were highly enriched over concentrations in underlying soils, indicating a predominately atmospheric source of Hg in lichens. However, MMHg and THg enrichment at coastal sites on Bathurst Island was far greater than on Devon Island. We suggest that this variability can be explained by the proximity of the Bathurst Island transect to several polynyas, which promote enhanced Hg deposition to adjacent landscapes through various biogeochemical processes. This study is the first to clearly show a strong marine influence on MMHg inputs to coastal terrestrial food webs with implications for MMHg accumulation in caribou and the health of the people who depend on them as part of a traditional diet.

  7. Developing strategies for automated remote plant production systems: Environmental control and monitoring of the Arthur Clarke Mars Greenhouse in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Bamsey, M.; Berinstain, A.; Graham, T.; Neron, P.; Giroux, R.; Braham, S.; Ferl, R.; Paul, A.-L.; Dixon, M.

    2009-12-01

    The Arthur Clarke Mars Greenhouse is a unique research facility dedicated to the study of greenhouse engineering and autonomous functionality under extreme operational conditions, in preparation for extraterrestrial biologically-based life support systems. The Arthur Clarke Mars Greenhouse is located at the Haughton Mars Project Research Station on Devon Island in the Canadian High Arctic. The greenhouse has been operational since 2002. Over recent years the greenhouse has served as a controlled environment facility for conducting scientific and operationally relevant plant growth investigations in an extreme environment. Since 2005 the greenhouse has seen the deployment of a refined nutrient control system, an improved imaging system capable of remote assessment of basic plant health parameters, more robust communication and power systems as well as the implementation of a distributed data acquisition system. Though several other Arctic greenhouses exist, the Arthur Clarke Mars Greenhouse is distinct in that the focus is on autonomous operation as opposed to strictly plant production. Remote control and autonomous operational experience has applications both terrestrially in production greenhouses and extraterrestrially where future long duration Moon/Mars missions will utilize biological life support systems to close the air, food and water loops. Minimizing crew time is an important goal for any space-based system. The experience gained through the remote operation of the Arthur Clarke Mars Greenhouse is providing the experience necessary to optimize future plant production systems and minimize crew time requirements. Internal greenhouse environmental data shows that the fall growth season (July-September) provides an average photosynthetic photon flux of 161.09 μmol m -2 s -1 (August) and 76.76 μmol m -2 s -1 (September) with approximately a 24 h photoperiod. The spring growth season provides an average of 327.51 μmol m -2 s -1 (May) and 339.32 μmol m -2 s

  8. Development and validation of a one-dimensional snow-ice algae model against observations in Resolute Passage, Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Pogson, L.; Tremblay, B.; Lavoie, D.; Michel, C.; Vancoppenolle, M.

    2011-04-01

    Ice algae are an important component of the carbon cycle in the Arctic. We investigate the dynamics of an ice algae bloom by coupling an ice algae-nutrient model with a multilayer σ coordinate thermodynamic sea ice model. The model is tested with the simulation of an algal bloom at the base of first-year ice over the spring. Model output is compared with data from Barrow Strait in the Canadian Arctic Archipelago. Snow cover, through its influence on ice melt, is a dominant factor controlling the decline of the bloom in the model, a finding that supports past studies. The results show that under a higher snow cover (20 cm), biomass in the early stages of the algal bloom is less than expected from the observed data. This discrepancy is due to the severely light-limited algal growth, despite the close match between simulated and observed under-ice photosynthetically active radiation. This result raises issues of how photosynthetic parameters as well as radiative transfer is represented in one-dimensional ice models. This study also shows that for higher algal concentrations, when biomass is split over multiple layers rather than concentrated in one layer at the ice base, there is a reduction in algae accumulation, a result of self shading. In addition, experiments show a sensitivity of total biomass to the oceanic heat flux and ice layer thickness, both of which affect biomass loss at the ice base. Being able to accurately model physical conditions is essential before the seasonal dynamics of ice algae can be accurately modeled, and some recommendations for improvement are discussed.

  9. Analysis of Decadal-Scale Shoreline Change along the Hamlet of Paulatuk (Canadian Arctic), using Landsat Satellite Imagery and GIS techniques from 1984 to 2014.

    NASA Astrophysics Data System (ADS)

    Sankar, R. D.; Murray, M. S.; Wells, P.

    2016-12-01

    Increased accuracy in estimating coastal change along localized segments of the Canadian Arctic coast is essential, in order to identify plausible adaptation initiatives to deal with the effects of climate change. This paper quantifies rates of shoreline movement along an 11 km segment of the Hamlet of Paulatuk (Northwest Territories, Canada), using an innovative modelling technique - Analyzing Moving Boundaries Using R (AMBUR). Approximately two dozen shorelines, obtained from high-resolution Landsat satellite imagery were analyzed. Shorelines were extracted using the band ratio method and compiled in ArcMapTM to determine decadal trends of coastal change. The unique geometry of Paulatuk facilitated an independent analysis of the western and eastern sections of the study area. Long-term (1984-2014) and short-term (1984-2003) erosion and accretion rates were calculated using the Linear Regression and End Point Rate methods respectively. Results reveal an elevated rate of erosion for the western section of the hamlet over the long-term (-1.1 m/yr), compared to the eastern portion (-0.92 m/yr). The study indicates a significant alongshore increase in the rates of erosion on both portions of the study area, over the short-term period 1984 to 2003. Mean annual erosion rates increased over the short-term along the western segment (-1.4 m/yr), while the eastern shoreline retreated at a rate of -1.3 m/yr over the same period. The analysis indicates that an amalgamation of factors may be responsible for the patterns of land loss experienced along Paulatuk. These include increased sea-surface temperature coupled with dwindling arctic ice and elevated storm hydrodynamics. The analysis further reveals that the coastline along the eastern portion of the hamlet, where the majority of the population reside, is vulnerable to a high rate of shoreline erosion.

  10. Extensive sampling of polar bears (Ursus maritimus) in the Northwest Passage (Canadian Arctic Archipelago) reveals population differentiation across multiple spatial and temporal scales.

    PubMed

    Campagna, Leonardo; Van Coeverden de Groot, Peter J; Saunders, Brenda L; Atkinson, Stephen N; Weber, Diana S; Dyck, Markus G; Boag, Peter T; Lougheed, Stephen C

    2013-09-01

    As global warming accelerates the melting of Arctic sea ice, polar bears (Ursus maritimus) must adapt to a rapidly changing landscape. This process will necessarily alter the species distribution together with population dynamics and structure. Detailed knowledge of these changes is crucial to delineating conservation priorities. Here, we sampled 361 polar bears from across the center of the Canadian Arctic Archipelago spanning the Gulf of Boothia (GB) and M'Clintock Channel (MC). We use DNA microsatellites and mitochondrial control region sequences to quantify genetic differentiation, estimate gene flow, and infer population history. Two populations, roughly coincident with GB and MC, are significantly differentiated at both nuclear (F ST = 0.01) and mitochondrial (ΦST = 0.47; F ST = 0.29) loci, allowing Bayesian clustering analyses to assign individuals to either group. Our data imply that the causes of the mitochondrial and nuclear genetic patterns differ. Analysis of mtDNA reveals the matrilineal structure dates at least to the Holocene, and is common to individuals throughout the species' range. These mtDNA differences probably reflect both genetic drift and historical colonization dynamics. In contrast, the differentiation inferred from microsatellites is only on the scale of hundreds of years, possibly reflecting contemporary impediments to gene flow. Taken together, our data suggest that gene flow is insufficient to homogenize the GB and MC populations and support the designation of GB and MC as separate polar bear conservation units. Our study also provide a striking example of how nuclear DNA and mtDNA capture different aspects of a species demographic history.

  11. A community-based, environmental chronic disease prevention intervention to improve healthy eating psychosocial factors and behaviors in indigenous populations in the Canadian Arctic.

    PubMed

    Mead, Erin L; Gittelsohn, Joel; Roache, Cindy; Corriveau, André; Sharma, Sangita

    2013-10-01

    Diet-related chronic diseases are highly prevalent among indigenous populations in the Canadian Arctic. A community-based, multi-institutional nutritional and lifestyle intervention-Healthy Foods North-was implemented to improve food-related psychosocial factors and behaviors among Inuit and Inuvialuit in four intervention communities (with two comparison communities) in Nunavut and the Northwest Territories, Canada, in 2008. The 12-month program was developed from theory (social cognitive theory and social ecological models), formative research, and a community participatory process. It included an environmental component to increase healthy food availability in local stores and activities consisting of community-wide and point-of-purchase interactive educational taste tests and cooking demonstrations, media (e.g., radio ads, posters, shelf labels), and events held in multiple venues, including recreation centers and schools. The intervention was evaluated using pre- and postassessments with 246 adults from intervention and 133 from comparison communities (311 women, 68 men; mean age 42.4 years; 78.3% retention rate). Outcomes included psychosocial constructs (healthy eating knowledge, self-efficacy, and behavioral intentions), frequency of healthy and unhealthy food acquisition, healthiness of commonly used food preparation methods, and body mass index (kg/m(2)). After adjustment for demographic, socioeconomic status, and body mass index variables, respondents living in intervention communities showed significant improvements in food-related self-efficacy (β = 0.15, p = .003) and intentions (β = 0.16, p = .001) compared with comparison communities. More improvements from the intervention were seen in overweight, obese, and high socioeconomic status respondents. A community-based, multilevel intervention is an effective strategy to improve psychosocial factors for healthy nutritional behavior change to reduce chronic disease in indigenous Arctic populations.

  12. Modelling Trace Gas Gluxes From Soils Along Slope Transects in Eastern Canadian Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Peng, C.; Chen, X.; Ullah, S.; Moore, T.; Li, C.

    2009-05-01

    Trace gases exchange between forest soils and atmosphere is important for Green House Gases (GHG) budget at both national and global scales. However, this part has not been included in the Canadian national GHG inventory yet. Although several sites have flux measurements, accurate larger scale fluxes are difficult to estimate due to the nature of spatial and temporal variability for gas generation and consumption processes. This study aims to simulate trace gas fluxes (mainly CH4 and N2O) at different landscape scales, using the process-based Forest-DNDC model. As the first part of the work, model has been parameterized and validated against flux measurements along slope transects at two deciduous forest stands at Mt. St. Hilaire (MSH) and Morgan Arboretum (MA), near Montreal, Quebec. The preliminary results suggest that both N2O and CH4 fluxes have two peaks during a year corresponding to snow melting and summer rain, respectively. The upland, riparian zone and wetland area at the two sites are sources of N gases dominated by N2O and N2. Both upland area and riparian zone act as a CH4 sink, while wetland a net source of CH4. Forest successional stage, tree species composition and the decomposition status of forest floor are possible controls on N gaseous flux at site level. The validation results proved that Forest-DNDC is able to capture trace gas exchange in different forest soils. The modeled patterns and magnitudes of fluxes were basically in agreement with observations for all studied plots. Further works for parameter optimization with inversion techniques are expected to improve the model performance before extrapolating the model to larger scale.

  13. Empirical Determinations of the Extent and Form of Ice-Proximal Water Bodies in the Canadian Arctic Archipelago During the Last Deglaciation

    NASA Astrophysics Data System (ADS)

    Leverington, D. W.

    2002-05-01

    Digital reconstructions of late Quaternary landscapes deformed by differential glacio-isostatic rebound can be made using a geographic information system (GIS) method that subtracts interpolated isobase values from modern elevations and bathymetry. A principal utility of the GIS method for reconstructing late Quaternary landscapes is in the relative ease and rapidity with which high-resolution, quantitative, and georeferenced databases of paleo-topography can be generated. Databases of paleo-topography can be used to approximately determine the positions of paleo-shorelines over large areas, and to estimate the extent and volume of ancient ice-proximal water bodies. By providing quantitative information on the dimensions of ice-proximal water bodies, such databases may in the future help to constrain models of crustal loading and isostasy in the arctic. Using modern elevations and bathymetry (derived from the GLOBE and ETOPO5 databases, respectively) and isobase data compiled by Dyke et al. (1991), the GIS method has been used to reconstruct the paleo-topography of the central region of the Canadian Arctic Archipelago at 9300 14C yr B.P. (latitudes 68 to 76 N, and longitudes 80 to 112 W). The new database of paleo-topography delineates the approximate shoreline and subaerial extent of the region's islands at 9300 14C yr B.P., and is a topographic and bathymetric model of the region at that time. The database demonstrates that the surface area of terrain above sea level in the study region (about 258,000 km2) was about 50% less than today, with reductions in the surface area of individual land units ranging between about 18% (e.g., Somerset Island, and Brodeur Peninsula on Baffin Island) and 100% (e.g., King William Island, which at 9300 14C yr B.P. was covered by the Laurentide Ice Sheet). Water volume within the study region (about 150,000 km3) was about 240% greater than today, and correspondingly the cross sectional areas of many channels in the region were more

  14. A trajectory analysis of atmospheric transport of black carbon aerosols to Canadian high Arctic in winter and spring (1990-2005)

    NASA Astrophysics Data System (ADS)

    Huang, L.; Gong, S. L.; Sharma, S.; Lavoué, D.; Jia, C. Q.

    2010-06-01

    Black carbon (BC) particles accumulated in the Arctic troposphere and deposited on snow have been calculated to have significant effects on radiative forcing of the Arctic regional climate. Applying cluster analysis technique on 10-day backward trajectories, seven distinct transport pathways (or clusters) affecting Alert (82.5° N, 62.5° W), Nunavut in Canada are identified in this work. Transport frequency associated with each pathway is obtained as the fraction of trajectories in that cluster. Based on atmospheric transport frequency and BC surface flux from surrounding regions (i.e. North America, Europe, and former USSR), a linear regression model is constructed to investigate the inter-annual variations of BC observed at Alert in January and April, representative of winter and spring respectively, between 1990 and 2005. Strong correlations are found between BC concentrations predicted with the regression model and measurements at Alert for both seasons (R2 equals 0.77 and 0.81 for winter and spring, respectively). Results imply that atmospheric transport and BC emission are the major contributors to the inter-annual variations in BC concentrations observed at Alert in the cold seasons for the 16-year period. Other factors, such as deposition, could also contribute to the variability in BC concentrations but were not considered in this analysis. Based on the regression model the relative contributions of regional BC emissions affecting Alert are attributed to the Eurasian sector, composed of the European Union and the former USSR, and the North American sector. Considering both seasons, the model suggests that former USSR is the major contributor to the near-surface BC levels at the Canadian high Arctic site with an average contribution of about 67% during the 16-year period, followed by European Union (18%) and North America (15%). In winter, the atmospheric transport of BC aerosols from Eurasia is found to be even more predominant with a multi-year average

  15. A trajectory analysis of atmospheric transport of black carbon aerosols to Canadian high Arctic in winter and spring (1990-2005)

    NASA Astrophysics Data System (ADS)

    Huang, L.; Gong, S.; Sharma, S.; Lavoue, D.; Jia, C. Q.

    2010-12-01

    Black carbon (BC) particles accumulated in the Arctic troposphere and deposited on snow have been calculated to have significant effects on radiative forcing of the Arctic regional climate. Applying cluster analysis technique on 10-day backward trajectories, seven distinct transport pathways (or clusters) affecting Alert (82.5° N, 62.5° W), Nunavut in Canada are identified in this work. Transport frequency associated with each pathway is obtained as the fraction of trajectories in that cluster. Based on atmospheric transport frequency and BC surface flux from surrounding regions (i.e. North America, Europe, and former USSR), a linear regression model is constructed to investigate the inter-annual variations of BC observed at Alert in January and April, representative of winter and spring respectively, between 1990 and 2005. Strong correlations are found between BC concentrations predicted with the regression model and measurements at Alert for both seasons (R2 equals 0.77 and 0.81 for winter and spring, respectively). Results imply that atmospheric transport and BC emission are the major contributors to the inter-annual variations in BC concentrations observed at Alert in the cold seasons for the 16-year period. Other factors, such as deposition, could also contribute to the variability in BC concentrations but were not considered in this analysis. Based on the regression model the relative contributions of regional BC emissions affecting Alert are attributed to the Eurasian sector, composed of the European Union and the former USSR, and the North American sector. Considering both seasons, the model suggests that former USSR is the major contributor to the near-surface BC levels at the Canadian high Arctic site with an average contribution of about 67% during the 16-year period, followed by European Union (18%) and North America (15%). In winter, the atmospheric transport of BC aerosols from Eurasia is found to be even more predominant with a multi-year average

  16. Inorganic carbon dynamics of melt-pond-covered first-year sea ice in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Geilfus, N.-X.; Galley, R. J.; Crabeck, O.; Papakyriakou, T.; Landy, J.; Tison, J.-L.; Rysgaard, S.

    2015-03-01

    Melt pond formation is a common feature of spring and summer Arctic sea ice, but the role and impact of sea ice melt and pond formation on both the direction and size of CO2 fluxes between air and sea is still unknown. Here we report on the CO2-carbonate chemistry of melting sea ice, melt ponds and the underlying seawater as well as CO2 fluxes at the surface of first-year landfast sea ice in the Resolute Passage, Nunavut, in June 2012. Early in the melt season, the increase in ice temperature and the subsequent decrease in bulk ice salinity promote a strong decrease of the total alkalinity (TA), total dissolved inorganic carbon (TCO2) and partial pressure of CO2 (pCO2) within the bulk sea ice and the brine. As sea ice melt progresses, melt ponds form, mainly from melted snow, leading to a low in situ melt pond pCO2 (36 μatm). The percolation of this low salinity and low pCO2 meltwater into the sea ice matrix decreased the brine salinity, TA and TCO2, and lowered the in situ brine pCO2 (to 20 μatm). This initial low in situ pCO2 observed in brine and melt ponds results in air-ice CO2 fluxes ranging between -0.04 and -5.4 mmol m-2 day-1 (negative sign for fluxes from the atmosphere into the ocean). As melt ponds strive to reach pCO2 equilibrium with the atmosphere, their in situ pCO2 increases (up to 380 μatm) with time and the percolation of this relatively high concentration pCO2 meltwater increases the in situ brine pCO2 within the sea ice matrix as the melt season progresses. As the melt pond pCO2 increases, the uptake of atmospheric CO2 becomes less significant. However, since melt ponds are continuously supplied by meltwater, their in situ pCO2 remains undersaturated with respect to the atmosphere, promoting a continuous but moderate uptake of CO2 (~ -1 mmol m-2 day-1) into the ocean. Considering the Arctic seasonal sea ice extent during the melt period (90 days), we estimate an uptake of atmospheric CO2 of -10.4 Tg of C yr-1. This represents an additional

  17. Supraglacial sulfur springs and associated biological activity in the Canadian high arctic - signs of life beneath the ice

    USGS Publications Warehouse

    Grasby, Stephen E.; Allen, Carlton C.; Longazo, Teresa G.; Lisle, John T.; Griffin, Dale W.; Beauchamp, Benoit

    2003-01-01

    Unique springs, discharging from the surface of an arctic glacier, release H2S and deposit native sulfur, gypsum, and calcite. The presence of sulfur in three oxidation states indicates a complex series of redox reactions. Physical and chemical conditions of the spring water and surrounding environment, as well as mineralogical and isotopic signatures, suggest biologically mediated reactions. Cell counts and DNA analyses confirm bacteria are present in the spring system, and a limited number of sequenced isolates suggests that complex communities of bacteria live within the glacial system.

  18. Mercury distribution in the skin of beluga (Delphinapterus leucas) and narwhal (Monodon monoceros) from the Canadian Arctic and mercury burdens and excretion by moulting.

    PubMed

    Wagemann, R; Kozlowska, H

    2005-12-01

    Beluga and narwhal skin as a whole (in Inuktitut known as "muktuk") is considered to be a delicacy by native Canadian and Greenland people. Individual strata of the skin, and muscle from 27 beluga from the western, and 20 narwhal from the eastern Canadian Arctic, were analyzed for mercury and the thickness and density of each skin layer was measured. Mercury was not uniformly distributed in the skin, but increased outwardly with each layer. The concentration was only 0.29 and 0.16 microg/g (wet wt) in the innermost layer (dermis) of belugas and narwhal respectively, and 1.5 and 1.4 microg/g (wet wt) in the outermost layer (degenerative epidermis) of beluga and narwhal, respectively. There was a significant (alpha=0.05) association between age and mercury concentration in each skin layer, the regression coefficients progressively increasing from the inner layer (dermis) to the outer layer: 0.011-0.063 microg/g year-1; 0.034 microg/g year-1 for skin as a whole; 0.054 microg/g year-1 for muscle. The concentration of total mercury was 0.84 and 0.59 microg/g (wet wt) in skin as a whole (muktuk) of beluga and narwhal respectively, and 0.12 and 0.03 microg/g in blubber, respectively. The average, total mercury concentration in muscle tissue was 1.4 and 0.81 microg/g wet wt, in beluga and narwhal respectively, exceeding (except for blubber) the Canadian Government's Guideline (0.5 microg/g wet wt) for fish export and consumption. The skin surface area of an average-size beluga and narwhal was estimated (6.10 and 6.50 m2, respectively), as were excretions of mercury through moulting (13,861 and 6721 microg year-1; 14 and 7 mg year-1) for belugas and narwhal, respectively. The whole-body mercury burden (699,300 microg; 700 mg) for a 1000 kg beluga and its various tissues were estimated, as was the fraction of mercury excreted by moulting (2-0.42% of the whole-body burden). Annual mercury burden increments in beluga skin, muscle and the whole body were estimated (2750; 17

  19. Arctic Gas Phase Water Vapor Measurements from the NASA DC-8 During SOLVE

    NASA Technical Reports Server (NTRS)

    Podolske, James; Sachse, Glen; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    The NASA Langley / Ames Diode Laser Hygrometer (DLH) was flown aboard the NASA DC-8 during all three arctic deployments of the SOLVE campaign. The DLH measures gas phase H2O in the freestream air between the fuselage and the outer right engine cowling, essentially free from aircraft perturbations. It uses wavelength-modulated near-IR laser radiation at about 1.4 microns to detect the H2O absorption. Calibration is based on short path experiments in the laboratory using a NIST-traceable dewpoint hygrometer with carefully conditioned air at dewpoints between - 10 and + 10 degrees C. The theory of operation of the DLH instrument will be presented, along with a description of the calibration methodology. A simple climatology of H2O observations from SOLVE will be presented.

  20. Impact origin of the Avak Structure, Arctic Alaska, and genesis of the Barrow gas fields

    USGS Publications Warehouse

    Kirschner, C.E.; Grantz, A.; Mullen, M.W.

    1992-01-01

    Geophysical and subsurface geologic data suggest that the Avak structure, which underlies the Arctic Coastal Plain 12 km southeast of Barrow, Alaska, is a hypervelocity meteorite or comet impact structure. The structure is a roughly circular area of uplifted, chaotically deformed Upper Triassic to Lower Cretaceous sedimentary rocks 8 km in diameter that is bounded by a ring of anastomosing, inwardly dipping, listric normal faults 12 km in diameter. Examination of cores from the Barrow gas fields and data concerning the age of the Avak structure suggest that the Avak meteorite struck a Late Cretaceous or Tertiary marine shelf or coastal plain between the Cenomanian (ca. 95 Ma), and deposition of the basal beds of the overlying late Pliocene and Quaternary Gubik Formation (ca. 3 Ma). -from Authors

  1. α- and γ-Hexachlorocyclohexane measurements in the brine fraction of sea ice in the Canadian High Arctic using a sump-hole technique.

    PubMed

    Pućko, M; Stern, G A; Macdonald, R W; Barber, D G

    2010-12-15

    We used holes augered partially into first-year sea ice (sumps) to determine α- and γ-HCH concentrations in sea-ice brine. The overwintering of the CCGS Amundsen in the Canadian western Arctic, as part of the Circumpolar Flaw Lead (CFL) System Study, provided the circumstances to allow brine to accumulate in sumps sufficiently to test the methodology. We show, for the first time, that as much as 50% of total HCHs in seawater can become entrapped within the ice crystal matrix. On average, in the winter first-year sea ice HCH brine concentrations reached 4.013 ± 0.307 ng/L and 0.423 ± 0.013 ng/L for the α- and γ-isomer, respectively. In the spring, HCHs decreased gradually with time, with increasing brine volume fraction and decreasing brine salinity. These decreasing concentrations could be accounted for by both the dilution with the ice crystal matrix and under-ice seawater. We propose that the former process plays a more significant role considering brine volume fractions calculated in this study were below 20%. Levels of HCHs in the brine exceed under-ice water concentrations by approximately a factor of 3, a circumstance suggesting that the brine ecosystem has been, and continues to be, the most exposed to HCHs.

  2. Contributions of growth and deformation to monthly variability in sea ice thickness north of the coasts of Greenland and the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Kwok, R.; Cunningham, G. F.

    2016-08-01

    Regional variability in monthly CryoSat-2 sea ice thickness is partitioned into contributions from dynamics and thermodynamics using ice deformation calculated from large-scale ice drift. For five winters (December to April, 2011-2015), over a region of persistent convergence north of the coasts of Greenland and the Canadian Arctic Archipelago, deformation explains 34% of the overall variance (up to 69% in 2014/2015) in monthly thickness changes. Approximately 42-56% (or 0.6 m) of the seasonal changes in mean regional ice thickness can be attributed to divergence and shear. The estimated area-averaged growth of 0.12 ± 0.03 m/month compares favorably with measurements from ice mass balance buoys. Examination of the time-variable thickness distributions shows areas covered by ice < 3 m are reduced, while areas of thicker ice (>3 m) increased. Albeit at fairly coarse resolution, this coupled analysis of thickness changes and deformation offered a first look at the character of the regional thickness redistribution process.

  3. Evidence for bacterially generated hydrocarbon gas in Canadian shield and Fennoscandian shield rocks

    SciTech Connect

    Lollar, B.S.; Frape, S.K. ); Fritz, P. ); Macko, S.A. ); Welhan, J.A. ); Blomqvist, R.; Lahermo, P.W. )

    1993-12-01

    Hydrocarbon-rich gases found in crystalline rocks on the Canadian and Fennoscandian shields are isotopically and compositionally similar, suggesting that such gases are a characteristic feature of Precambrian Shields rocks. Gases occur in association with saline groundwaters and brines in pressurized [open quotes]pockets[close quotes] formed by sealed fracture systems within the host rocks. When released by drilling activities, gas pressures as high as 5000 kPa have been recorded. Typical gas flow rates for individual boreholes range from 0.25 L/min to 4 L/min. The highest concentrations of CH[sub 4] are found in the deepest levels of the boreholes associated with Ca-Na-Cl (and Na-Ca-Cl) brines. N[sub 2] is the second major component of the gases and with CH[sub 4] accounts for up to 80 to >90 vol%. Higher hydrocarbon (C[sup +][sub 2]) concentrations range from <1 to 10 vol%, with Cl/(C2 + C3) ratios from 10-1000. Isotopically the gases show a wide range of values overall ([delta][sup 13]C = -57.5 to -41.1%; [delta]D = -245 to -470%) but a relatively tight cluster of values within each sampling locality. The Enonkoski Mine methanes are unique with [delta][sup 13]C values between -65.4 and -67.3% and [delta]D values between -297 and -347%. The shield gases are not readily reconcilable with conventional theories of methanogenesis. The range of C1/(C2 + C3) ratios for the shield gases is too low to be consistent with an entirely bacterial origin. In addition, [delta]D[sub CH4] values are in general too depleted in the heavy isotope to be produced by thermogenic methanogenesis or by secondary alteration processes such as bacterial oxidation or migration. However, isotopic and compositional evidence indicates that bacterially derived gas can account for a significant component of the gas at all shield sites.

  4. Stability of permafrost and gas hydrates in Arctic coastal lowlands and on the Eurasian shelf

    NASA Astrophysics Data System (ADS)

    Hubberten, H. W.; Lantuit, H.; Overduin, P. P.; Romanovskii, N.; Wetterich, S.

    2011-12-01

    During the last Glacial period thick continuous permafrost developed on the Siberian coastal lowlands and large shelf areas due to the up to 120 m lower sea level and the exposure of these areas to cold temperatures. With the beginning of the Holocene transgression, complex interaction processes of sea water with the permafrost landscape occurred. The occurrence of gas hydrates captured in permafrost is a characteristic feature of the the Eurasian Arctic shelf areas, especially on the shelf of the Kara, Laptev and East Siberia seas. In some of the shelf areas oceanic rift zones stretch to the continent, as for example in the Laptev Sea area where the Gakkel Ridge continues into the land. Great differences in geothermal heat flow values and in the properties of the sediments and rocks have to be assumed in undisturbed lithosphere block and in fault zones like as in continental rifts (such as Momskii and Baikalskii rifts, etc.). As a result differences in the thickness of permafrost and the gas hydrate stability zone (GHSZ) within these structures are expected. The thickness of permafrost and the GHSZ change essentially and irregularly in the stages of regressions and transgressions of the sea. Models show that the thickness of offshore (subsea) permafrost in the stages of climatic warming and transgressions essentially decrease however, rather irregular. The possibilities and the boundary conditions for the occurrence of open taliks, which may result in an emission of greenhouse gases from sub-permafrost gases and hydrates, have been estimated. Ice-bearing and ice-bonded permafrost in the northern regions of Arctic lowlands and in the inner shelf zone, have been preserved during at least four Pleistocene climatic and glacial-eustatic cycles. Presently, they are subjected to degradation from the bottom under the impact of geothermal heat flux as well as from interaction with warmer sea water at the top. Subsea permafrost formed on the arctic continental shelves that

  5. Tectonic Map of the Ellesmerian and Eurekan deformation belts on Svalbard, North Greenland and the Queen Elizabeth Islands (Canadian Arctic)

    NASA Astrophysics Data System (ADS)

    Piepjohn, Karsten; von Gosen, Werner; Tessensohn, Franz; Reinhardt, Lutz; McClelland, William C.; Dallmann, Winfried; Gaedicke, Christoph; Harrison, Christopher

    2016-04-01

    The tectonic map presented here shows the distribution of the major post-Ellesmerian and pre-Eurekan sedimentary basins, parts of the Caledonian Orogen, the Ellesmerian Fold-and-Thrust Belt, structures of the Cenozoic Eurekan deformation, and areas affected by the Eurekan overprint. The present continental margin of North America towards the Arctic Ocean between the Queen Elizabeth Islands and Northeast Greenland and the present west margin of the Barents Shelf are characterized by the Paleozoic Ellesmerian Fold-and-Thrust Belt, the Cenozoic Eurekan deformation, and, in parts, the Caledonian Orogen. In many areas, the structural trends of the Ellesmerian and Eurekan deformations are more or less parallel, and often, structures of the Ellesmerian Orogeny are affected or reactivated by the Eurekan deformation. While the Ellesmerian Fold-and-Thrust Belt is dominated by orthogonal compression and the formation of wide fold-and-thrust zones on Ellesmere Island, North Greenland and Spitsbergen, the Eurekan deformation is characterized by a complex network of regional fold-and-thrust belts (Spitsbergen, central Ellesmere Island), large distinct thrust zones (Ellesmere Island, North Greenland) and a great number of strike-slip faults (Spitsbergen, Ellesmere Island). The Ellesmerian Fold-and-Thrust Belt was most probably related to the approach and docking of the Pearya Terrane (northernmost part of Ellesmere Island) and Spitsbergen against the north margin of Laurasia (Ellesmere Island/North Greenland) in the earliest Carboniferous. The Eurekan deformation was related to plate tectonic movements during the final break-up of Laurasia and the opening of Labrador Sea/Baffin Bay west, the Eurasian Basin north, and the Norwegian/Greenland seas east of Greenland. The tectonic map presented here shows the German contribution to the Tectonic Map of the Arctic 1:5,000,000 (TeMAr) as part of the international project "Atlas of geological maps of Circumpolar Arctic at 1

  6. Active microwave measurements of sea ice under fall conditions: The RADARSAT/FIREX fall experiment. [in the Canadian Arctic

    NASA Technical Reports Server (NTRS)

    Onstott, R. G.; Kim, Y. S.; Moore, R. K.

    1984-01-01

    A series of measurements of the active microwave properties of sea ice under fall growing conditions was conducted. Ice in the inland waters of Mould Bay, Crozier Channel, and intrepid inlet and ice in the Arctic Ocean near Hardinge Bay was investigated. Active microwave data were acquired using a helicopter borne scatterometer. Results show that multiyear ice frozen in grey or first year ice is easily detected under cold fall conditions. Multiyear ice returns were dynamic due to response to two of its scene constituents. Floe boundaries between thick and thin ice are well defined. Multiyear pressure ridge returns are similar in level to background ice returns. Backscatter from homogeneous first year ice is seen to be primarily due to surface scattering. Operation at 9.6 GHz is more sensitive to the detailed changes in scene roughness, while operation at 5.6 GHz seems to track roughness changes less ably.

  7. Controls on Weathering of Pyrrhotite in a Low-Sulfide, Granitic Mine-Waste Rock in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Langman, J. B.; Holland, S.; Sinclair, S.; Blowes, D.

    2013-12-01

    Increased environmental risk is incurred with expansion of mineral extraction in the Arctic. A greater understanding of geochemical processes associated with hard-rock mining in this cold climate is needed to evaluate and mitigate these risks. A laboratory and in-situ experiment was conducted to examine mineral weathering and the generation of acid rock drainage in a low-sulfide, run-of-mine waste rock in an Arctic climate. Rock with different concentrations of sulfides (primarily pyrrhotite [Fe7S8] containing small amounts of Co and Ni) and carbonates were weathered in the laboratory and in-situ, large-scale test piles to examine leachate composition and mineral weathering. The relatively larger sulfide-containing rock produced sufficient acid to overcome carbonate buffering and produced a declining pH environment with concomitant release of SO4, Fe, Co, and Ni. Following carbonate consumption, aluminosilicate buffering stabilized the pH above 4 until a reduction in acid generation. Results from the laboratory experiment assisted in determining that after consumption of 1.6 percent of the total sulfide, the larger sulfide-concentration test pile likely is at an internal steady-state or maximal weathering rate after seven years of precipitation input and weathering that is controlled by an annual freeze-thaw cycle. Further weathering of the test pile should be driven by external factors of temperature and precipitation in this Arctic, semi-arid region instead of internal factors of wetting and non-equilibrium buffering. It is predicted that maximal weathering will continue until at least 20 percent of the total sulfide is consumed. Using the identified evolution of sulfide consumption in this Arctic climate, a variable rate factor can now be assessed for the possible early evolution and maximal weathering of larger scale waste-rock piles and seasonal differences because of changes in the volume of a waste-rock pile undergoing active weathering due to the freeze

  8. Changing dietary patterns in the Canadian Arctic: frequency of consumption of foods and beverages by inuit in three Nunavut communities.

    PubMed

    Sheehy, Tony; Kolahdooz, Fariba; Roache, Cindy; Sharma, Sangita

    2014-06-01

    Inuit in Arctic regions are experiencing a rapid diet and lifestyle transition. There are limited data on food consumption patterns among this unique population, raising concerns about assessing the risk for the development of diet-related chronic diseases. To assess the current frequency of consumption of foods and beverages among Inuit in Nunavut, Arctic Canada. A cross-sectional dietary study was conducted among randomly selected Inuit adults from three communities in Nunavut using a validated quantitative food frequency questionnaire. The participants were 175 women and 36 men with median (IQR) ages of 41.0 (32.5-48.5) and 40.1 (30.0-50.0) years, respectively. The mean and median frequencies of consumption over a 30-day period were computed for 147 individual food items and grouped as foods or beverages. The 30 most frequently consumed foods were identified. Non-nutrient-dense foods (i.e., high-fat and high-sugar foods) were the most frequently consumed food group (median intake, 3.4 times/day), followed by grains (2.0 times/day) and traditional meats (1.7 times/day). The frequency of consumption of fruits (0.7 times/day) and vegetables (0.4 times/day) was low. The median values for the three most frequently consumed food items were sugar or honey (once/day), butter (0.71 times/day), and Coffee-mate (0.71 times/day). Apart from water, coffee, and tea, the most frequently consumed beverages were sweetened juices (0.71 times/day) and regular pop (soft drinks) (0.36 times/day). This study showed that non-nutrient-dense foods are consumed most frequently in these Inuit communities. The results have implications for dietary quality and provide useful information on current dietary practices to guide nutritional intervention programs.

  9. Arctic greenhouse-gas storage and release modulated by late-glacial ice sheet fluctuations

    NASA Astrophysics Data System (ADS)

    Portnov, Alexey; Mienert, Jurgen; Vadakkepuliyambatta, Sunil; Patton, Henry; Andreassen, Karin; Winsborrow, Monica; Knies, Jochen; Hubbard, Alun I.

    2016-04-01

    The subglacial footprint of the Barents Sea Ice sheet which advanced across northern Eurasia from 26 to 22 ka BP had a major impact on the underlying gas hydrate stability zone (GHSZ) leading to storage of methane and other hydrocarbons. With the onset of deglaciation, these hydrocarbon rich hydrates dissociated, releasing potent greenhouse gas into the ocean and possibly atmosphere over a period of thousands of years. We present a wide-range of observational data acquired from offshore western Svalbard and the Barents Sea to robustly constrain a coupled model of the subglacial evolution of gas hydrate reservoirs during and after the Last Glacial Maximum (LGM). Our results indicate that even under minimum ice thickness reconstructions, an extensive, ~500-meter thick GHSZ existed beneath the ice sheet in our study area offshore of western Svalbard (Portnov et al., 2016). An offshore corridor of methane release did though also persist throughout maximum ice conditions on the upper continental margin. Throughout the LGM a marine ice sheet directly comparable to those of Greenland and Antarctica today inundated the continental margin offshore of western Svalbard and the vast shelf areas of the Barents Sea. However, with climatic amelioration the Barents Sea ice sheet experienced a 4ka period of dynamic retreat with concurrent flooding of the shelf by rising sea levels, which provided a high magnitude perturbation to the substrate pressure and temperature domains. By analogy, the future response of Polar ice sheets is an emerging concern as their ongoing thinning and retreat will likewise perturb the present day subglacial GHSZ leading to potential widespread gas hydrate destabilisation and release. Portnov, Alexey, et al. "Ice-sheet-driven methane storage and release in the Arctic", Nature Comm. DOI: 10.1038/ncomms10314. (2016).

  10. High Arctic tundra greenhouse gas fluxes: new insights from Adventdalen, Svalbard

    NASA Astrophysics Data System (ADS)

    Pirk, N.; Parmentier, F. J. W.; Mastepanov, M.; Christiansen, H. H.; Christensen, T. R.

    2014-12-01

    Data on greenhouse gas (GHG) exchange in high Arctic environments is rare but badly needed, as the environment in these places will likely respond early and most rapidly to climate warming. Also, the high Arctic holds carbon stocks in permafrost that is most likely to be made vulnerable to decomposition as ecosystems get warmer. In 2011 we established a long-term GHG flux-monitoring site in the Adventdalen valley on the Svalbard archipelago. The site is characterised by little precipitation (about 200 mm/year), a strong marine influence (summer air temperatures predominantly around 5 degrees Celsius), and a continuous permafrost ground with low-centered ice wedge polygons at the surface. The measurement equipment features an eddy-covariance tower and an automatic chamber system, both set up in accordance with already existing monitoring programs (INTERACT, ICOS and the Greenland Ecosystem Monitoring program). Here, we present the first results of this multi-year campaign, such as the pattern of carbon dioxide and methane fluxes during the growing and shoulder seasons, including the recently discovered autumn burst, as well as carbon dioxide fluxes during wintertime. Carbon dioxide fluxes measured with eddy-covariance agree well with the automatic chamber data, and indicate that the site acts as a sink for carbon dioxide. Methane fluxes measured by the automatic chamber system indicate a significant methane source, which is, however, weaker than at comparable sites in Greenland. There is a high degree of inter-annual variation in methane emissions, which seems to be driven by the amount of precipitation in summer. On top of that, there is a strong spatial variability resembling the polygonal ground pattern. This variability is also reflected in the occurrence of the methane autumn burst, which could be detected and is spatially and temporally distributed at a few locations and years.

  11. Engineering and Economics of the USGS Circum-Arctic Oil and Gas Resource Appraisal (CARA) Project

    USGS Publications Warehouse

    Verma, Mahendra K.; White, Loring P.; Gautier, Donald L.

    2008-01-01

    This Open-File report contains illustrative materials, in the form of PowerPoint slides, used for an oral presentation given at the Fourth U.S. Geological Survey Workshop on Reserve Growth of petroleum resources held on March 10-11, 2008. The presentation focused on engineering and economic aspects of the Circum-Arctic Oil and Gas Resource Appraisal (CARA) project, with a special emphasis on the costs related to the development of hypothetical oil and gas fields of different sizes and reservoir characteristics in the North Danmarkshavn Basin off the northeast coast of Greenland. The individual PowerPoint slides highlight the topics being addressed in an abbreviated format; they are discussed below, and are amplified with additional text as appropriate. Also included in this report are the summary results of a typical ?run? to generate the necessary capital and operating costs for the development of an offshore oil field off the northeast coast of Greenland; the data are displayed in MS Excel format generated using Questor software (IHS Energy, Inc.). U.S. Geological Survey (USGS) acknowledges that this report includes data supplied by IHS Energy, Inc.; Copyright (2008) all rights reserved. IHS Energy has granted USGS the permission to publish this report.

  12. History of petroleum development in Arctic Alaska

    SciTech Connect

    Gryc, G. )

    1991-03-01

    Long before recorded history, tar from oil seepages and oil shale that burned like wood were used for fuel by the Inuit (native people of Arctic Alaska). The first published descriptions of these oil seepages that identified Arctic Alaska as a petroliferous province appeared in 1909. In 1921, several applications for prospecting permits were filed by private groups under the old mining laws, but the permits were never issued. In 1923, President Harding set aside about half of the North Slope of Alaska, including most of the seepage areas, as Naval Petroleum Reserve No. 4. This was followed by three periods of federally sponsored exploration programs in the reserve and the adjoining areas during the periods 1923 to 1926, 1944 to 1952, and 1974 to 1982. Noncommercial oil and gas deposits were discovered in the reserve, the gas deposits at Barrow were developed for local use, and the feasibility of petroleum exploration and development in the Arctic was established. Industry exploration began in 1958 when the lands adjacent to the reserve were opened for lease. Prudhoe Bay, North America's largest oil field, was discovered in 1968. The history of petroleum development in Arctic Alaska provides an interesting study of the building of a geologic, geographic, and logistic base, of the lead time required for resource exploitation, of the interaction of government and industry, and of the expansion of the US resource base during a time of expanding ecologic awareness. Petroleum exploration in the Canadian Arctic region was stimulated by the activity across the border in Alaska.

  13. Holocene sea ice history and climate variability along the main axis of the Northwest Passage, Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Ledu, David; Rochon, André; de Vernal, Anne; Barletta, Francesco; St-Onge, Guillaume

    2010-06-01

    Palynological, geochemical, and physical records were used to document Holocene paleoceanographic changes in marine sediment core from Dease Strait in the western part of the main axis of the Northwest Passage (core 2005-804-006 PC latitude 68°59.552‧N, longitude 106°34.413‧W). Quantitative estimates of past sea surface conditions were inferred from the modern analog technique applied to dinoflagellate cyst assemblages. The chronology of core 2005-804-006 PC is based on a combined use of the paleomagnetic secular variation records and the CALS7K.2 time-varying spherical harmonic model of the geomagnetic field. The age-depth model indicates that the core spans the last ˜7700 cal years B.P., with a sedimentation rate of 61 cm ka-1. The reconstructed sea surface parameters were compared with those from Barrow Strait and Lancaster Sound (cores 2005-804-004 PC and 2004-804-009 PC, respectively), which allowed us to draw a millennial-scale Holocene sea ice history along the main axis of the Northwest Passage (MANWP). Overall, our data are in good agreement with previous studies based on bowhead whale remains. However, dinoflagellate sea surface based reconstructions suggest several new features. The presence of dinoflagellate cysts in the three cores for most of the Holocene indicates that the MANWP was partially ice-free over the last 10,000 years. This suggests that the recent warming observed in the MANWP could be part of the natural climate variability at the millennial time scale, whereas anthropogenic forcing could have accelerated the warming over the past decades. We associate Holocene climate variability in the MANWP with a large-scale atmospheric pattern, such as the Arctic Oscillation, which may have operated since the early Holocene. In addition to a large-scale pattern, more local conditions such as coastal current, tidal effects, or ice cap proximity may have played a role on the regional sea ice cover. These findings highlight the need to further

  14. Contrasting retinoid and thyroid hormone status in differentially-contaminated northern fulmar colonies from the Canadian Arctic, Svalbard and the Faroe Islands.

    PubMed

    Verreault, Jonathan; Helgason, Lisa B; Gabrielsen, Geir W; Dam, Maria; Braune, Birgit M

    2013-02-01

    The northern fulmar (Fulmarus glacialis) has previously been shown to accumulate a wide range, and occasionally high concentrations of organochlorines (OCs) (e.g., PCBs, chlorobenzenes, DDT- and chlordane-related compounds, dioxins and furans). The present study aimed to investigate, using a meta-analysis approach, the variations in cytochrome P450 (CYP) 1A-like enzyme induction based on ethoxyresorufin O-deethylase activity (EROD) and selected physiological variables (retinoids and thyroid hormones) in northern fulmar breeding in three differentially OC-exposed populations: Nunavut (Canadian Arctic), Svalbard (Norwegian Arctic) and the Faroe Islands. Substantially higher (roughly two-fold) OC levels were uncovered in the liver of this long-lived fulmarine petrel breeding in the Faroe Islands relative to Svalbard and Nunavut. Liver levels of PCDDs, PCDFs and non-ortho PCBs in Faroe Islands fulmars were amongst the highest reported thus far in any seabirds from the northern regions. Positive correlations were depicted in combined fulmars (all three populations) between hepatic EROD activity and concentrations of OCs, in which strongest associations were found for dioxin-like compound (PCDFs and PCDDs) and TEQ concentrations. Moreover, moderate to strong positive correlations were found between liver OC concentrations and plasma total thyroxin (TT(4)) levels and TT(4)/total triiodothyronine (TT(3)) level ratios, as well as strong negative correlations between the same suite of OCs and plasma TT(3) levels. Hepatic OC concentrations (PCBs, PCDDs, PCDFs, HCB, p,p'-DDE and oxychlordane) also were positively correlated with hepatic retinyl palmitate levels which, in turn, were associated with a significant decrease in plasma retinol levels and somewhat unchanged liver retinol levels. The present meta-analysis investigation on northern fulmar breeding in three geographically-distant sites illustrated that OC exposure (mainly PCBs and dioxins/furans) may be associated with

  15. Present heat flow and paleo-geothermal regime in the Canadian Arctic margin: analysis of industrial thermal data and coalification gradients

    NASA Astrophysics Data System (ADS)

    Majorowicz, Jacek A.; Embry, Ashton F.

    1998-06-01

    Calculations of the present geothermal gradient and terrestrial heat flow were made on 156 deep wells of the Canadian Arctic Archipelago. Corrected bottom hole temperature (BHT) data and drill stem test (DST) temperatures were used to determine the thermal gradients for sites for which the quality of data was sufficient. Thermal gradients evaluated for depths below the base of permafrost for the onshore wells and below sea bottom for the offshore wells were combined with the estimates of effective thermal conductivity to approximate heat flow for these sites. The present geothermal gradient is in the 15-50 mK/m range (mean = 31 ± 7 mK/m). Present heat flow is mainly in the 35-90 mW/m 2 range (mean = 53 ± 12 mW/m 2). Maps of the present geothermal gradient and present heat flow have been constructed for the basin. The analysis of vitrinite reflectance profiles and the calculation of logarithmic coalification gradients for 101 boreholes in the Sverdrup Basin showed large variations related in many cases to regional variations of present terrestrial heat flow. Paleo-geothermal gradients estimated from these data are mostly in the range of 15-50 mK/m (mean = 28 ± 9 mK/m) and paleo-heat flow is in the 40-90 mW/m 2 range (mean = 57 ± 18 mW/m 2) related to the time of maximum burial in the Early Tertiary. Mean values of the present heat flow and paleo-heat flow for the Sverdrup Basin are almost identical considering the uncertainties of the methods used (53 ± 12 versus 57 ± 18 mW/m 2, respectively). Present geothermal gradients and paleo-geothermal gradients are also close when means are compared (31 ± 7 versus 28 ± 9 mK/m respectively). A zone of high present heat flow and a paleo-heat flow zone coincide in places with the northeastern-southwestern incipient rift landward of the Arctic margin first described by Balkwill and Fox (1982). Correlation between present heat flow and paleo-heat flow for the time of maximum burial in the earliest Tertiary suggests that

  16. Total mercury concentrations in anadromous Northern Dolly Varden from the northwestern Canadian Arctic: a historical baseline study.

    PubMed

    Tran, L; Reist, J D; Power, M

    2015-03-15

    Previous research has documented the significance of total mercury (THg) as a northern contaminant in general and of fish in particular. While much research has been devoted to documenting both spatial and temporal changes in THg in consumed fish, little effort has been directed at understanding patterns of THg in Dolly Varden (Salvelinus malma), a prized subsistence species throughout the western North American Arctic. Here we report historical THg concentrations for anadromous Dolly Varden from 10 populations in the Yukon and Northwest Territories sampled across a range of latitudes (67-69°N) and longitudes (136-141°W) between the years 1988-91. Unadjusted mean THg concentrations ranged from 15 to 254 ng/g wet weight. Length-adjusted THg concentrations were significantly different among sites, but were not related to latitude or longitude. Within and among populations, THg was significantly related to fork-length, age, δ(15)N, and δ(13)C, with the variation in THg found among populations being best explained by size. The data serve as an important baseline against which future changes in THg levels in this important subsistence fishery may be compared to determine the significance of any observed trends.

  17. Adapting to the impacts of climate change on food security among Inuit in the Western Canadian Arctic.

    PubMed

    Wesche, Sonia D; Chan, Hing Man

    2010-09-01

    This study examined critical impacts of climate change on Inuit diet and nutritional health in four Inuit communities in the Inuvialuit Settlement Region, Western Arctic, Canada. The first objective was to combine data from community observation studies and dietary interview studies to determine potential climate change impacts on nutritional quality. The second objective was to address the scale of data collection and/or availability to compare local versus regional trends, and identify implications for adaptation planning. Information was compiled from 5 reports (4 community reports and 1 synthesis report) of climate change observations, impacts and adaptations in 12 Inuit communities (2005-2006), and from a dietary report of food use from 18 Inuit communities (1997-2000). Changing access to, availability of, quality of, and ability to use traditional food resources has implications for quality of diet. Nutritional implications of lower traditional food use include likely reductions in iron, zinc, protein, vitamin D, and omega-3 fatty acids, among others. The vulnerability of each community to changing food security is differentially influenced by a range of factors, including current harvesting trends, levels of reliance on individual species, opportunities for access to other traditional food species, and exposure to climate change hazards. Understanding linkages between climate change and traditional food security provides a basis for strengthening adaptive capacity and determining effective adaptation options to respond to future change.

  18. Arctic terrestrial ecosystem contamination.

    PubMed

    Thomas, D J; Tracey, B; Marshall, H; Norstrom, R J

    1992-07-15

    Limited data have been collected on the presence of contaminants in the Arctic terrestrial ecosystem, with the exception of radioactive fallout from atmospheric weapons testing. Although southern and temperate biological systems have largely cleansed themselves of radioactive fallout deposited during the 1950s and 1960s, Arctic environments have not. Lichens accumulate radioactivity more than many other plants because of their large surface area and long life span; the presence and persistence of radioisotopes in the Arctic is of concern because of the lichen----reindeer----human ecosystem. Effective biological half-life of cesium 137 is reckoned to be substantially less than its physical half-life. The database on organochlorines in Canadian Arctic terrestrial mammals and birds is very limited, but indications are that the air/plant/animal contaminant pathway is the major route of these compounds into the terrestrial food chain. For terrestrial herbivores, the most abundant organochlorine is usually hexachlorobenzene followed by hexachlorocyclohexane isomers. PCB accumulation favours the hexachlorobiphenyl, pentachlorobiphenyl and heptachlorobiphenyl homologous series. The concentrations of the various classes of organochlorine compounds are substantially lower in terrestrial herbivore tissues than in marine mammal tissues. PCBs and DDT are the most abundant residues in peregrine falcons (a terrestrial carnivore) reaching average levels of 9.2 and 10.4 micrograms.g-1, respectively, more than 10 times higher than other organochlorines and higher than in marine mammals, including the polar bear. Contaminants from local sources include metals from mining activities, hydrocarbons and waste drilling fluids from oil and gas exploration and production, wastes from DEW line sites, naturally occurring radionuclides associated with uranium mineralization, and smoke containing SO2 and H2SO4 aerosol from the Smoking Hills at Cape Bathurst, N.W.T.

  19. Satellite observation of pollutant emissions from gas flaring activities near the Arctic

    NASA Astrophysics Data System (ADS)

    Li, Can; Hsu, N. Christina; Sayer, Andrew M.; Krotkov, Nickolay A.; Fu, Joshua S.; Lamsal, Lok N.; Lee, Jaehwa; Tsay, Si-Chee

    2016-05-01

    Gas flaring is a common practice in the oil industry that can have significant environmental impacts, but has until recently been largely overlooked in terms of relevance to climate change. We utilize data from various satellite sensors to examine pollutant emissions from oil exploitation activities in four areas near the Arctic. Despite the remoteness of these sparsely populated areas, tropospheric NO2 retrieved from the Ozone Monitoring Instrument (OMI) is substantial at ˜1 × 1015 molecules cm-2, suggesting sizeable emissions from these industrial activities. Statistically significant (at the 95% confidence level, corresponding uncertainties in parentheses) increasing trends of 0.017 (±0.01) × 1015 and 0.015 (±0.006) × 1015 molecules cm-2 year-1 over 2004-2015 were found for Bakken (USA) and Athabasca (Canada), two areas having recently experienced fast expansion in the oil industry. This rapid change has implications for emission inventories, which are updated less frequently. No significant trend was found for the North Sea (Europe), where oil production has been declining since the 1990s. For northern Russia, the trend was just under the 95% significance threshold at 0.0057 (±0.006) × 1015 molecules cm-2 year-1. This raises an interesting inconsistency as prior studies have suggested that, in contrast to the continued, albeit slow, expansion of Russian oil/gas production, gas flaring in Russia has decreased in recent years. However, only a fraction of oil fields in Russia were covered in our analysis. Satellite aerosol optical depth (AOD) data revealed similar tendencies, albeit at a weaker level of statistical significance, due to the longer lifetime of aerosols and contributions from other sources. This study demonstrates that synergetic use of data from multiple satellite sensors can provide valuable information on pollutant emission sources that is otherwise difficult to acquire.

  20. Spatial variability of particle-attached and free-living bacterial diversity in surface waters from the Mackenzie River to the Beaufort Sea (Canadian Arctic)

    NASA Astrophysics Data System (ADS)

    Ortega-Retuerta, E.; Joux, F.; Jeffrey, W. H.; Ghiglione, J. F.

    2013-04-01

    We explored the patterns of total and active bacterial community structure in a gradient covering surface waters from the Mackenzie River to the coastal Beaufort Sea in the Canadian Arctic Ocean, with a particular focus on free-living (FL) vs. particle-attached (PA) communities. Capillary electrophoresis-single-strand conformation polymorphism (CE-SSCP) showed significant differences when comparing river, coast and open sea bacterial community structures. In contrast to the river and coastal waters, total (16S rDNA-based) and active (16S rRNA-based) communities in the open sea samples were not significantly different, suggesting that most present bacterial groups were equally active in this area. Additionally, we observed significant differences between PA and FL bacterial community structure in the open sea, but similar structure in the two fractions for coastal and river samples. Direct multivariate statistical analyses showed that total community structure was mainly driven by salinity (a proxy of dissolved organic carbon and chromophoric dissolved organic matter), suspended particles, amino acids and chlorophyll a. Pyrosequencing of 16S rRNA genes from selected samples confirmed significant differences between river, coastal and sea samples. The PA fraction was only different (15.7% similarity) from the FL one in the open sea sample. Furthermore, PA samples generally showed higher diversity (Shannon, Simpson and Chao indices) than FL samples. At the class level, Opitutae was most abundant in the PA fraction of the sea sample, followed by Flavobacteria and Gammaproteobacteria, while the FL sea sample was dominated by Alphaproteobacteria. Finally, for the coast and river samples and both PA and FL fractions, Betaproteobacteria, Alphaproteobacteria and Actinobacteria were dominant. These results highlight the coexistence of particle specialists and generalists and the role of particle quality in structuring bacterial communities in the area. These results may also

  1. Spatial variability of particle-attached and free-living bacterial diversity in surface waters from the Mackenzie River to the Beaufort Sea (Canadian Arctic)

    NASA Astrophysics Data System (ADS)

    Ortega-Retuerta, E.; Joux, F.; Jeffrey, W. H.; Ghiglione, J.-F.

    2012-12-01

    We explored the patterns of total and active bacterial community structure in a gradient covering surface waters from the Mackenzie River to the coastal Beaufort Sea, Canadian Arctic Ocean, with a particular focus on free-living vs. particle-attached communities. Capillary electrophoresis-single strand conformation polymorphism (CE-SSCP) showed significant differences when comparing river, coast and open sea bacterial community structures. In contrast to the river and coastal waters, total (16S rDNA-based) and active (16S rRNA-based) communities in the open sea samples were not significantly different, suggesting that most present bacterial groups were equally active in this area. Additionally, we observed significant differences between particle-attached (PA) and free-living (FL) bacterial communities in the open sea, but similar structure in the two fractions for coastal and river samples. Direct multivariate statistical analyses showed that total community structure was mainly driven by salinity (proxy of DOC and CDOM), suspended particles, amino acids and chlorophyll a. 16S rRNA genes pyrosequencing of selected samples confirmed these significant differences from river to sea and also between PA and FL fractions only in open sea samples, and PA samples generally showed higher diversity (Shannon, Simpson and Chao indices) than FL samples. At the class level, Opitutae was most abundant in the PA fraction of the sea sample, followed by Flavobacteria and Gammaproteobacteria, while the FL sea sample was dominated by Alphaproteobacteria. Finally, the coast and river samples, both PA and FL fractions, were dominated by Betaproteobacteria, Alphaproteobacteria and Actinobacteria. These results highlight the coexistence of particle specialists and generalists and the role of particle quality in structuring bacterial communities in the area. These results may also serve as a~basis to predict further changes in bacterial communities should climate change lead to further

  2. Current-use pesticides in seawater and their bioaccumulation in polar bear-ringed seal food chains of the Canadian Arctic.

    PubMed

    Morris, Adam D; Muir, Derek C G; Solomon, Keith R; Letcher, Robert J; McKinney, Melissa A; Fisk, Aaron T; McMeans, Bailey C; Tomy, Gregg T; Teixeira, Camilla; Wang, Xiaowa; Duric, Mark

    2016-07-01

    The distribution of current-use pesticides (CUPs) in seawater and their trophodynamics were investigated in 3 Canadian Arctic marine food chains. The greatest ranges of dissolved-phase concentrations in seawater for each CUP were endosulfan sulfate (less than method detection limit (MDL) to 19 pg L(-1) ) > dacthal (0.76-15 pg L(-1) ) > chlorpyrifos (less than MDL to 8.1 pg L(-1) ) > pentachloronitrobenzene (less than MDL to 2.6 pg L(-1) ) > α-endosulfan (0.20-2.3 pg L(-1) ). Bioaccumulation factors (BAFs, water-respiring organisms) were greatest in plankton, including chlorothalonil (log BAF = 7.4 ± 7.1 L kg(-1) , mean ± standard error), chlorpyrifos (log BAF = 6.9 ± 6.7 L kg(-1) ), and α-endosulfan (log BAF = 6.5 ± 6.0 L kg(-1) ). The largest biomagnification factors (BMFs) were found for dacthal in the capelin:plankton trophic relationship (BMF = 13 ± 5.0) at Cumberland Sound (Nunvavut), and for β-endosulfan (BMF = 16 ± 4.9) and α-endosulfan (BMF = 9.3 ± 2.8) in the polar bear-ringed seal relationship at Barrow and Rae Strait (NU), respectively. Concentrations of endosulfan sulfate exhibited trophic magnification (increasing concentrations with increasing trophic level) in the poikilothermic portion of the food web (trophic magnification factor = 1.4), but all of the CUPs underwent trophic dilution in the marine mammal food web, despite some trophic level-specific biomagnification. Together, these observations are most likely indicative of metabolism of these CUPs in mammals. Environ Toxicol Chem 2016;35:1695-1707. © 2016 SETAC. © 2016 SETAC.

  3. Regional differences in collagen stable isotope and tissue trace element profiles in populations of long-tailed duck breeding in the Canadian Arctic.

    PubMed

    Braune, Birgit M; Hobson, Keith A; Malone, Brian J

    2005-06-15

    Adult long-tailed ducks (Clangula hyemalis) were collected from nine locations across their breeding grounds in northern Canada and measurements of stable isotopes of carbon (delta(13)C), nitrogen (delta(15)N) and sulfur (delta(34)S) in bone collagen were used to investigate if relative use of freshwater habitats such as the Great Lakes (with expected depleted stable isotope profiles) compared with coastal marine environments (with expected enriched stable isotope foodweb profiles) could explain tissue trace element profiles. Contrary to expectation, all three stable isotopes did not covary in our sample, suggesting that mechanisms other than simple freshwater vs. marine isotopic gradients were involved among populations. All three stable isotopes varied significantly with collection location and both delta(15)N and delta(13)C values varied significantly between sexes suggesting that males exploit either a different food base or occur in different geographic areas than females for at least part of the year. The delta(34)S data, in particular, suggested that many of the birds breeding in the western Canadian Arctic probably overwinter in the Great Lakes along with many of the birds breeding in Hudson Bay. Males at the majority of collection locations had higher concentrations of hepatic Hg (1.1-8 microg/g dw), Cu (25-40 mug/g dw), Se (7.3-27 mug/g dw) and renal Cd (33-129 microg/g dw) than females. Concentrations of Hg, Cu and Cd were well below toxicological threshold levels found in the literature. However, hepatic Se concentrations in 64% of the females exceeded 10 mug/g dw and concentrations in 8% of the birds measured exceeded 33 microg/g dw suggesting levels of potential concern.

  4. Heterotrophic microbial colonization of the interior of impact-shocked rocks from Haughton impact structure, Devon Island, Nunavut, Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Fike, David A.; Cockell, Charles; Pearce, David; Lee, Pascal

    2002-10-01

    The polar desert is one of the most extreme environments on Earth. Endolithic organisms can escape or mitigate the hazards of the polar desert by using the resources available in the interior of rocks. We examined endolithic communities within crystalline rocks that have undergone shock metamorphism as a result of an asteroid or comet impact. Specifically, we present a characterization of the heterotrophic endolithic community and its environment in the interior of impact-shocked gneisses and their host polymict breccia from the Haughton impact structure on Devon Island, Nunavut, Canadian High Arctic. Microbiological colonization of impact-shocked rocks is facilitated by impact-induced fissures and cavities, which occur throughout the samples, the walls of which are lined with high abundances of biologically important elements owing to the partial volatilization of minerals within the rock during the impact. 27 heterotrophic bacteria were isolated from these shocked rocks and were identified by 16S rDNA sequencing. The isolates from the shocked gneiss and the host breccia are similar to each other, and to other heterotrophic communities isolated from polar environments, suggesting that the interiors of the rocks are colonized by microorganisms from the surrounding country rocks and soils. Inductively coupled plasma atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis were used to identify the chemical composition of the shocked materials and to document the in situ growth of microbes in their interiors. The identification of these heterotrophic communities within impact-shocked crystalline rocks extends our knowledge of the habitable biosphere on Earth. The colonization of the interiors of these samples has astrobiological applications both for considering terrestrial, microbiological contamination of meteorites from the Antarctic ice sheet and for investigating possible habitats for microbial

  5. Carbon flows through the microbial food web of first-year ice in resolute passage (Canadian High Arctic)

    NASA Astrophysics Data System (ADS)

    Vézina, Alain F.; Demers, Serge; Laurion, Isabelle; Sime-Ngando, Télesphore; Kim Juniper, S.; Devine, Laure

    1997-02-01

    Ice algal communities are host to thriving populations of microheterotrophs whose trophic role remains poorly understood. We report here an inverse modelling analysis of the microbial food web associated with the spring bloom of ice algae at Resolute Passage in the High Arctic. Carbon flows among microbial components (ice algae, autotrophic and heterotrophic nanoflagellates, microflagellates and ciliates) and their exchanges with particulate and dissolved organic carbon (POC and DOC) were inferred from the observed changes in standing stocks of these compartments between 13 April and 22 May 1992. Calculations were made for three phases of the bloom's development and for two sites under thin and thick snow cover. Observed DOC accumulations within the bottom ice originated largely from the ice algae. However, calculated production rates were too high to result strictly from normal physiological exudation. Mechanical or physiological stresses that disrupt the integrity of the cells and grazing by zooplankton at the ice-water interface may well be involved in this process. Inverse modelling confirmed field and experimental evidence that nanoflagellates may directly assimilate DOC to support their growth. Patterns in trophic flows between sites with thin and thick snow cover were similar. In contrast, trophic interactions changed as the bloom progressed: production of DOC and detritus from the ice algae were the only significant carbon flows during the early phase; bacterivory developed and peaked during the middle phase and was superseded by DOC utilization and herbivory by flagellates and ciliates during the late phase. Only ca. 20% of the DOC produced was utilized by the microheterotrophs. Direct links from DOC and ice algae to protists potentially increase the efficiency of C transfers within the ice-associated microbial food web; on the other hand, low recovery efficiency limits the role of the microbial loop in recycling DOC.

  6. Mid to Late Holocene hydroclimatic and geochemical records from the varved sediments of East Lake, Cape Bounty, Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Cuven, Stéphanie; Francus, Pierre; Lamoureux, Scott

    2011-09-01

    A long sedimentary sequence from East Lake, Cape Bounty, Melville Island (74°55'N; 109°30'W) contains a 4200 year-long clastic varved record of paleohydrologic variations at high resolution. Sedimentary elemental geochemistry from micro X-ray fluorescence (μ-XRF) and sediment fabric variability reflect changes in sediment sources and lacustrine conditions through time. The sedimentary environment progressed from marine in the mid-Holocene, to estuarian from 2195 B