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Atmospheric Concentrations and Wet/Dry Loadings of Mercury at the Remote Experimental Lakes Area, Northwestern Ontario, Canada.

https://arctichealth.org/en/permalink/ahliterature301563
Source
Environ Sci Technol. 2019 Jul 16; 53(14):8017-8026
Publication Type
Journal Article
Date
Jul-16-2019
Author
Vincent L St Louis
Jennifer A Graydon
Igor Lehnherr
Helen M Amos
Elsie M Sunderland
Kyra A St Pierre
Craig A Emmerton
Ken Sandilands
Michael Tate
Alexandra Steffen
Elyn R Humphreys
Author Affiliation
Department of Biological Sciences , University of Alberta , Edmonton , Alberta T6G 2E9 , Canada.
Source
Environ Sci Technol. 2019 Jul 16; 53(14):8017-8026
Date
Jul-16-2019
Language
English
Publication Type
Journal Article
Abstract
Mercury (Hg) is a global pollutant released from both natural and human sources. Here we compare long-term records of wet deposition loadings of total Hg (THg) in the open to dry deposition loadings of THg in throughfall and litterfall under four boreal mixedwood canopy types at the remote Experimental Lakes Area (ELA) in Northwestern Ontario, Canada. We also present long-term records of atmospheric concentrations of gaseous elemental (GEM), gaseous oxidized (GOM), and particle bound (PBM) Hg measured at the ELA. We show that dry THg loadings in throughfall and litterfall are 2.7 to 6.1 times greater than wet THg loadings in the open. GEM concentrations showed distinct monthly and daily patterns, correlating positively in spring and summer with rates of gross ecosystem productivity and respiration. GOM and PBM concentrations were less variable throughout the year but were highest in the winter, when concentrations of anthropogenically sourced particles and gases were also high. Forest fires, Arctic air masses, and road salt also impacted GEM, GOM, and PBM concentrations at the ELA. A nested GEOS-Chem simulation for the ELA region produced a dry/wet deposition ratio of >5, suggesting that the importance of dry deposition in forested regions can be reasonably modeled by existing schemes for trace gases.
PubMed ID
31250626 View in PubMed
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Fate and Transport of Perfluoroalkyl Substances from Snowpacks into a Lake in the High Arctic of Canada.

https://arctichealth.org/en/permalink/ahliterature310082
Source
Environ Sci Technol. 2019 Sep 17; 53(18):10753-10762
Publication Type
Journal Article
Date
Sep-17-2019
Author
John J MacInnis
Igor Lehnherr
Derek C G Muir
Kyra A St Pierre
Vincent L St Louis
Christine Spencer
Amila O De Silva
Author Affiliation
Department of Chemistry , Memorial University , St. John's , Newfoundland and Labrador A1B 3X7 , Canada.
Source
Environ Sci Technol. 2019 Sep 17; 53(18):10753-10762
Date
Sep-17-2019
Language
English
Publication Type
Journal Article
Keywords
Arctic Regions
Canada
Environmental monitoring
Fluorocarbons
Lakes
Nunavut
Abstract
The delivery of perfluoroalkyl substances (PFAS) from snowpacks into Lake Hazen, located on Ellesmere Island (Nunavut, Canada, 82° N) indicates that annual atmospheric deposition is a major source of PFAS that undergo complex cycling in the High Arctic. Perfluoroalkyl carboxylic acids (PFCA) in snowpacks display odd-even concentration ratios characteristic of long-range atmospheric transport and oxidation of volatile precursors. Major ion analysis in snowpacks suggests that sea spray, mineral dust, and combustion aerosol are all relevant to the fate of PFAS in the Lake Hazen watershed. Distinct drifts of light and dark snow (enriched with light absorbing particles, LAPs) facilitate the study of particle loads on the fate of PFAS in the snowpack. Total PFAS (SPFAS, ng m-2) loads are lower in snowpacks enriched with LAPs and are attributed to reductions in snowpack albedo combined with enhanced post-depositional melting. Elevated concentrations of PFCA are observed in the top 5 m of the water column during snowmelt periods compared to ice-covered or ice-free periods. PFAS concentrations in deep waters of the Lake Hazen water column were consistent between snowmelt, ice-free, and ice-covered periods, which is ascribed to the delivery of dense and turbid glacier meltwaters mixing PFAS throughout the Lake Hazen water column. These observations highlight the underlying mechanisms in PFAS cycling in High Arctic Lakes particularly in the context of increased particle loads and melting.
PubMed ID
31412696 View in PubMed
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Glacial Melt Inputs of Organophosphate Ester Flame Retardants to the Largest High Arctic Lake.

https://arctichealth.org/en/permalink/ahliterature307065
Source
Environ Sci Technol. 2020 03 03; 54(5):2734-2743
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
03-03-2020
Author
Yuxin Sun
Amila O De Silva
Kyra A St Pierre
Derek C G Muir
Christine Spencer
Igor Lehnherr
John J MacInnis
Author Affiliation
CAS Key Laboratory of Tropical Marine Bio-resources and Ecology; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, P. R. China.
Source
Environ Sci Technol. 2020 03 03; 54(5):2734-2743
Date
03-03-2020
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Arctic Regions
Ecosystem
Environmental monitoring
Esters
Flame Retardants
Lakes
Organophosphates
Abstract
Organophosphate esters (OPEs) have been detected in the Arctic environment, but the influence of glacial melt on the environmental behavior of OPEs in recipient Arctic aquatic ecosystems is still unknown. In this study, water samples were collected from Lake Hazen (LH) and its tributaries to investigate the distribution of 14 OPEs in LH and to explore the input of OPEs from glacial rivers to LH and the output of OPEs from LH in 2015 and 2018. S14OPE concentrations in water of LH were lower than glacial rivers and its outflow, the Ruggles River. In 2015, a high melt year, we estimated that glacial rivers contributed 7.0 ± 3.2 kg OPEs to LH, compared to a 16.5 ± 0.3 kg OPEs output by the Ruggles River, suggesting that residence time and/or additional inputs via direct wet and dry deposition and permafrost melt likely result in OPE retention in the LH watershed. In 2018, a lower melt year, S14OPE concentrations in glacial rivers were much lower, indicating that the rate of glacier melt may govern, in part, the concentrations of OPEs in the tributaries of LH. This study highlights long-range transport of OPEs, their deposition in Arctic glaciers, landscapes, and lakes.
PubMed ID
32013404 View in PubMed
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Physicochemical Drivers of Microbial Community Structure in Sediments of Lake Hazen, Nunavut, Canada.

https://arctichealth.org/en/permalink/ahliterature292428
Source
Front Microbiol. 2018; 9:1138
Publication Type
Journal Article
Date
2018
Author
Matti O Ruuskanen
Kyra A St Pierre
Vincent L St Louis
Stéphane Aris-Brosou
Alexandre J Poulain
Author Affiliation
Department of Biology, University of Ottawa, Ottawa, ON, Canada.
Source
Front Microbiol. 2018; 9:1138
Date
2018
Language
English
Publication Type
Journal Article
Abstract
The Arctic is undergoing rapid environmental change, potentially affecting the physicochemical constraints of microbial communities that play a large role in both carbon and nutrient cycling in lacustrine environments. However, the microbial communities in such Arctic environments have seldom been studied, and the drivers of their composition are poorly characterized. To address these gaps, we surveyed the biologically active surface sediments in Lake Hazen, the largest lake by volume north of the Arctic Circle, and a small lake and shoreline pond in its watershed. High-throughput amplicon sequencing of the 16S rRNA gene uncovered a community dominated by Proteobacteria, Bacteroidetes, and Chloroflexi, similar to those found in other cold and oligotrophic lake sediments. We also show that the microbial community structure in this Arctic polar desert is shaped by pH and redox gradients. This study lays the groundwork for predicting how sediment microbial communities in the Arctic could respond as climate change proceeds to alter their physicochemical constraints.
Notes
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PubMed ID
29922252 View in PubMed
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Proglacial freshwaters are significant and previously unrecognized sinks of atmospheric CO2.

https://arctichealth.org/en/permalink/ahliterature302723
Source
Proc Natl Acad Sci U S A. 2019 Sep 03; 116(36):17690-17695
Publication Type
Journal Article
Date
Sep-03-2019
Author
Kyra A St Pierre
Vincent L St Louis
Sherry L Schiff
Igor Lehnherr
Paul G Dainard
Alex S Gardner
Pieter J K Aukes
Martin J Sharp
Author Affiliation
Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; kyra2@ualberta.ca.
Source
Proc Natl Acad Sci U S A. 2019 Sep 03; 116(36):17690-17695
Date
Sep-03-2019
Language
English
Publication Type
Journal Article
Abstract
Carbon dioxide (CO2) emissions from freshwater ecosystems are almost universally predicted to increase with climate warming. Glacier-fed rivers and lakes, however, differ critically from those in nonglacierized catchments in that they receive little terrestrial input of organic matter for decomposition and CO2 production, and transport large quantities of easily mobilized comminuted sediments available for carbonate and silicate weathering reactions that can consume atmospheric CO2 We used a whole-watershed approach, integrating concepts from glaciology and limnology, to conclusively show that certain glacier-fed freshwater ecosystems are important and previously overlooked annual CO2 sinks due to the overwhelming influence of these weathering reactions. Using the glacierized Lake Hazen watershed (Nunavut, Canada, 82°N) as a model system, we found that weathering reactions in the glacial rivers actively consumed CO2 up to 42 km downstream of glaciers, and cumulatively transformed the High Arctic's most voluminous lake into an important CO2 sink. In conjunction with data collected at other proglacial freshwater sites in Greenland and the Canadian Rockies, we suggest that CO2 consumption in proglacial freshwaters due to glacial melt-enhanced weathering is likely a globally relevant phenomenon, with potentially important implications for regional annual carbon budgets in glacierized watersheds.
PubMed ID
31427515 View in PubMed
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The use of hair as a proxy for total and methylmercury burdens in polar bear muscle tissue.

https://arctichealth.org/en/permalink/ahliterature310083
Source
Sci Total Environ. 2019 Oct 10; 686:1120-1128
Publication Type
Journal Article
Date
Oct-10-2019
Author
Thea Bechshoft
Markus Dyck
Kyra A St Pierre
Andrew E Derocher
Vincent St Louis
Author Affiliation
University of Alberta, Department of Biological Sciences, Edmonton, Alberta T6G 2E9, Canada. Electronic address: thea.bechshoft@gmail.com.
Source
Sci Total Environ. 2019 Oct 10; 686:1120-1128
Date
Oct-10-2019
Language
English
Publication Type
Journal Article
Keywords
Animals
Arctic Regions
Environmental Monitoring - methods
Female
Hair - chemistry
Humans
Male
Mercury - analysis
Methylmercury compounds - analysis
Muscles - chemistry
Nunavut
Risk assessment
Ursidae - metabolism
Abstract
Polar bears (Ursus maritimus) are an ecologically important species in the Arctic, whose health, and that of the people whose livelihoods depend on them, are increasingly affected by climate change and the bioaccumulation of contaminants such as mercury (Hg). Although methylmercury (MeHg) is the toxic form of Hg that biomagnifies up food webs, risk assessment studies typically only report on total Hg (THg) concentrations because it is cheaper to quantify. Furthermore, hair is commonly analysed for THg in polar bear as well as human risk assessment studies because it is relatively non-invasive to collect, yet we know little of how THg and MeHg concentrations differ between hair and muscle tissues. In this study, we quantified THg and MeHg concentrations in hair and muscle from 44 polar bears (24 sub-adults: 9 females, 15 males; 18 adults: 5 females, 13 males, and 2 males of unknown age group), harvested in 2015 and 2016 from four subpopulations in Nunavut, Canada (Davis Strait, n?=?3; Gulf of Boothia, n?=?8; Baffin Bay, n?=?15; Foxe Basin, n?=?18). We found only moderately positive correlations (0.4?=?r?=?0.5) between THg concentrations in hair and THg and MeHg concentrations in muscle. Further, 75% and 88% of THg was MeHg in hair and muscle, respectively. High concentrations of THg in hair - 71% of the samples were above the suggested neurochemical no observed effect level for polar bears - suggest some of the bears may be adversely affected by Hg-related health effects. Despite this, all MeHg concentrations in muscle (0.1 to 0.4 mg/kg (wet weight, ww)) were below the consumption maximum Hg concentration of 0.5 mg/kg (ww) set by Canadian health authorities.
PubMed ID
31412508 View in PubMed
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Warming Climate Is Reducing the Diversity of Dominant Microbes in the Largest High Arctic Lake.

https://arctichealth.org/en/permalink/ahliterature304307
Source
Front Microbiol. 2020; 11:561194
Publication Type
Journal Article
Date
2020
Author
Graham A Colby
Matti O Ruuskanen
Kyra A St Pierre
Vincent L St Louis
Alexandre J Poulain
Stéphane Aris-Brosou
Author Affiliation
Department of Biology, University of Ottawa, Ottawa, ON, Canada.
Source
Front Microbiol. 2020; 11:561194
Date
2020
Language
English
Publication Type
Journal Article
Abstract
Temperatures in the Arctic are expected to increase dramatically over the next century, and transform high latitude watersheds. However, little is known about how microbial communities and their underlying metabolic processes will be affected by these environmental changes in freshwater sedimentary systems. To address this knowledge gap, we analyzed sediments from Lake Hazen, NU Canada. Here, we exploit the spatial heterogeneity created by varying runoff regimes across the watershed of this uniquely large high-latitude lake to test how a transition from low to high runoff, used as one proxy for climate change, affects the community structure and functional potential of dominant microbes. Based on metagenomic analyses of lake sediments along these spatial gradients, we show that increasing runoff leads to a decrease in taxonomic and functional diversity of sediment microbes. Our findings are likely to apply to other, smaller, glacierized watersheds typical of polar or high latitude ecosystems; we can predict that such changes will have far reaching consequences on these ecosystems by affecting nutrient biogeochemical cycling, the direction and magnitude of which are yet to be determined.
PubMed ID
33133035 View in PubMed
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The world's largest High Arctic lake responds rapidly to climate warming.

https://arctichealth.org/en/permalink/ahliterature290815
Source
Nat Commun. 2018 Mar 29; 9(1):1290
Publication Type
Journal Article
Date
Mar-29-2018
Author
Igor Lehnherr
Vincent L St Louis
Martin Sharp
Alex S Gardner
John P Smol
Sherry L Schiff
Derek C G Muir
Colleen A Mortimer
Neil Michelutti
Charles Tarnocai
Kyra A St Pierre
Craig A Emmerton
Johan A Wiklund
Günter Köck
Scott F Lamoureux
Charles H Talbot
Author Affiliation
Department of Geography, University of Toronto-Mississauga, Mississauga, ON, L5L 1C6, Canada. igor.lehnherr@utoronto.ca.
Source
Nat Commun. 2018 Mar 29; 9(1):1290
Date
Mar-29-2018
Language
English
Publication Type
Journal Article
Abstract
Using a whole-watershed approach and a combination of historical, contemporary, modeled and paleolimnological datasets, we show that the High Arctic's largest lake by volume (Lake Hazen) has succumbed to climate warming with only a ~1?°C relative increase in summer air temperatures. This warming deepened the soil active layer and triggered large mass losses from the watershed's glaciers, resulting in a ~10 times increase in delivery of glacial meltwaters, sediment, organic carbon and legacy contaminants to Lake Hazen, a >70% decrease in lake water residence time, and near certainty of summer ice-free conditions. Concomitantly, the community assemblage of diatom primary producers in the lake shifted dramatically with declining ice cover, from shoreline benthic to open-water planktonic species, and the physiological condition of the only fish species in the lake, Arctic Char, declined significantly. Collectively, these changes place Lake Hazen in a biogeochemical, limnological and ecological regime unprecedented within the past ~300 years.
Notes
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PubMed ID
29599477 View in PubMed
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8 records – page 1 of 1.