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6 records – page 1 of 1.

Contemporary and preindustrial mass budgets of mercury in the Hudson Bay Marine System: the role of sediment recycling.

https://arctichealth.org/en/permalink/ahliterature92210
Source
Sci Total Environ. 2008 Nov 15;406(1-2):190-204
Publication Type
Article
Date
Nov-15-2008
Author
Hare Alexander
Stern Gary A
Macdonald Robie W
Kuzyk Zou Zou
Wang Feiyue
Author Affiliation
Department of Environment and Geography, University of Manitoba, Winnipeg, Canada MB R3T 2N2.
Source
Sci Total Environ. 2008 Nov 15;406(1-2):190-204
Date
Nov-15-2008
Language
English
Publication Type
Article
Keywords
Arctic Regions
Atmosphere - chemistry
Canada
Climate
Conservation of Natural Resources - economics - methods
Environmental Monitoring - methods
Geography
Geologic Sediments - analysis - chemistry
Mercury - analysis - chemistry
Models, Biological
Rivers
Seawater
Time Factors
Water Pollutants, Chemical - analysis - chemistry
Abstract
Based on extensive sampling of the rivers, troposphere, seawater and sediments, mercury (Hg) mass budgets are constructed for both contemporary and preindustrial times in the Hudson Bay Marine System (HBS) to probe sources and pathways of Hg and their responses to the projected climate change. The contemporary total Hg inventory in the HBS is estimated to be 98 t, about 1% of which is present in the biotic systems and the remainder in the abiotic systems. The total contemporary Hg influx and outflux, around 6.3 t/yr each, represent a 2-fold increase from the preindustrial fluxes. The most notable changes are in the atmospheric flux, which has gone from a nearly neutral (0.1 t/yr) to source term (1.5 t/yr), increased river inputs (which may also reflect increased atmospheric deposition to the HBS watershed) and in the sedimentary burial flux which has increased by 2.4 t/yr over preindustrial values, implying that much of the modern Hg loading entering this system is buried in the sediments. The capacity to drive increased Hg loading from the atmosphere to sediment burial may be supported by the resuspension of an extraordinarily large flux (120 Mt/yr) of shallow water glacigenic sediments uncontaminated by anthropogenic Hg, which could scavenge Hg from the water column before being transported to the deeper accumulative basins. Under the projected climate warming in the region, the rate of the sediment recycling pump will likely increase due to enhanced Hg scavenging by increasing biological productivity, and thus strengthen atmosphere-ocean Hg exchanges in the HBS.
PubMed ID
18765159 View in PubMed
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The delivery of mercury to the Beaufort Sea of the Arctic Ocean by the Mackenzie River.

https://arctichealth.org/en/permalink/ahliterature95684
Source
Sci Total Environ. 2007 Feb 1;373(1):178-95
Publication Type
Article
Date
Feb-1-2007
Author
Leitch Daniel R
Carrie Jesse
Lean David
Macdonald Robie W
Stern Gary A
Wang Feiyue
Author Affiliation
Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.
Source
Sci Total Environ. 2007 Feb 1;373(1):178-95
Date
Feb-1-2007
Language
English
Publication Type
Article
Keywords
Environmental monitoring
Fires
Geological Phenomena
Geology
Greenhouse Effect
Mercury - analysis
Methylmercury compounds - analysis
Oceans and Seas
Rivers - chemistry
Seasons
Water Movements
Water Pollutants, Chemical - analysis
Abstract
Very high levels of mercury (Hg) have recently been reported in marine mammals and other higher trophic-level biota in the Mackenzie Delta and Beaufort Sea of the western Arctic Ocean. To quantify the input of Hg (particulate, dissolved and methylated) by the Mackenzie River as a potential source for Hg in the ecosystem, surface water and sediment samples were taken from 79 sites in the lower Mackenzie Basin during three consecutive summers (2003-2005) and analyzed for Hg and methylmercury (MeHg). Intensive studies were also carried out in the Mackenzie Delta during the freshets of 2004 and 2005. Large seasonal and annual variations were found in Hg concentrations in the river, coincident with the variations in water discharge. Increased discharges during spring freshet and during the summers of 2003 and 2005 compared to 2004 were mirrored by higher Hg concentrations. The correlation between Hg concentration and riverflow suggests additional Hg sources during periods of high water, potentially from increased surface inundation and increased bank erosion. The increase in the Hg concentration with increasing water discharge amplifies the annual Hg and MeHg fluxes during high water level years. For the period 2003-2005, the Hg and MeHg fluxes from the Mackenzie River to the Beaufort Sea averaged 2.2 tonnes/yr and 15 kg/yr, respectively, the largest known Hg source to the Beaufort Sea. More than half of the mercury flux occurs during the short spring freshet season which coincides with the period of rapid growth of marine biota. Consequently, the Mackenzie River input potentially provides the major mercury source to marine mammals of the Beaufort Sea. The Hg and MeHg fluxes from the Mackenzie River are expected to further increase with the projected climate warming in the Mackenzie Basin.
PubMed ID
17169406 View in PubMed
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Effects of ultraviolet radiation and contaminant-related stressors on arctic freshwater ecosystems.

https://arctichealth.org/en/permalink/ahliterature95664
Source
Ambio. 2006 Nov;35(7):388-401
Publication Type
Article
Date
Nov-2006
Author
Wrona Frederick J
Prowse Terry D
Reist James D
Hobbie John E
Lévesque Lucie M J
Macdonald Robie W
Vincent Warwick F
Author Affiliation
National Water Research Institute of Environment Canada, Department of Geography, University of Victoria, BC. fred.wrona@ec.gc.ca
Source
Ambio. 2006 Nov;35(7):388-401
Date
Nov-2006
Language
English
Publication Type
Article
Keywords
Adaptation, Biological
Animals
Arctic Regions
Cold Climate
Ecosystem
Fresh Water
Greenhouse Effect
Ice
Mercury
Snow
Ultraviolet Rays
Water Pollutants
Abstract
Climate change is likely to act as a multiple stressor, leading to cumulative and/or synergistic impacts on aquatic systems. Projected increases in temperature and corresponding alterations in precipitation regimes will enhance contaminant influxes to aquatic systems, and independently increase the susceptibility of aquatic organisms to contaminant exposure and effects. The consequences for the biota will in most cases be additive (cumulative) and multiplicative (synergistic). The overall result will be higher contaminant loads and biomagnification in aquatic ecosystems. Changes in stratospheric ozone and corresponding ultraviolet radiation regimes are also expected to produce cumulative and/or synergistic effects on aquatic ecosystem structure and function. Reduced ice cover is likely to have a much greater effect on underwater UV radiation exposure than the projected levels of stratospheric ozone depletion. A major increase in UV radiation levels will cause enhanced damage to organisms (biomolecular, cellular, and physiological damage, and alterations in species composition). Allocations of energy and resources by aquatic biota to UV radiation protection will increase, probably decreasing trophic-level productivity. Elemental fluxes will increase via photochemical pathways.
PubMed ID
17256643 View in PubMed
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Interactions between climate change and contaminants.

https://arctichealth.org/en/permalink/ahliterature95593
Source
Mar Pollut Bull. 2007 Dec;54(12):1845-56
Publication Type
Article
Date
Dec-2007
Author
Schiedek Doris
Sundelin Brita
Readman James W
Macdonald Robie W
Author Affiliation
Baltic Sea Research Institute Warnemünde, Seestrasse 15, 18119 Rostock, Germany. doris.schiedek@io-warnemuende.de
Source
Mar Pollut Bull. 2007 Dec;54(12):1845-56
Date
Dec-2007
Language
English
Publication Type
Article
Keywords
Air Pollutants - metabolism - toxicity
Animals
Arctic Regions
Climate
Ecosystem
Environmental monitoring
Greenhouse Effect
Humans
Oceans and Seas
Temperature
Time Factors
Water Pollutants, Chemical - metabolism - toxicity
Abstract
There is now general consensus that climate change is a global threat and a challenge for the 21st century. More and more information is available demonstrating how increased temperature may affect aquatic ecosystems and living resources or how increased water levels may impact coastal zones and their management. Many ecosystems are also affected by human releases of contaminants, for example from land based sources or the atmosphere, which also may cause severe effects. So far these two important stresses on ecosystems have mainly been discussed independently. The present paper is intended to increase awareness among scientists, coastal zone managers and decision makers that climate change will affect contaminant exposure and toxic effects and that both forms of stress will impact aquatic ecosystems and biota. Based on examples from different ecosystems, we discuss risks anticipated from contaminants in a rapidly changing environment and the research required to understand and predict how on-going and future climate change may alter risks from chemical pollution.
PubMed ID
17963794 View in PubMed
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Mercury in the Arctic: are we overlooking the ocean?

https://arctichealth.org/en/permalink/ahliterature95459
Source
Integr Environ Assess Manag. 2009 Jan;5(1):178-80
Publication Type
Article
Date
Jan-2009
Author
Macdonald Robie W
Wang Feiyue
Stern Gary
Outridge Peter
Author Affiliation
University of Manitoba, Winnipeg, MB, Canada. robie.macdonald@dfo-mpo.gc.ca
Source
Integr Environ Assess Manag. 2009 Jan;5(1):178-80
Date
Jan-2009
Language
English
Publication Type
Article
Keywords
Arctic Regions
Environmental Pollutants - chemistry
Greenhouse Effect
Mercury - chemistry
Methylmercury Compounds - chemistry - toxicity
Oceans and Seas
PubMed ID
19132817 View in PubMed
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Seabird-driven shifts in Arctic pond ecosystems.

https://arctichealth.org/en/permalink/ahliterature95480
Source
Proc Biol Sci. 2009 Feb 7;276(1656):591-6
Publication Type
Article
Date
Feb-7-2009
Author
Michelutti Neal
Keatley Bronwyn E
Brimble Samantha
Blais Jules M
Liu Huijun
Douglas Marianne S V
Mallory Mark L
Macdonald Robie W
Smol John P
Author Affiliation
Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6. nm37@queensu.ca
Source
Proc Biol Sci. 2009 Feb 7;276(1656):591-6
Date
Feb-7-2009
Language
English
Publication Type
Article
Keywords
Animal Migration
Animals
Arctic Regions
Charadriiformes - physiology
Ecosystem
Fresh Water
Geologic sediments
Greenhouse Effect
Water Pollutants, Chemical
Abstract
Migratory animals such as seabirds, salmon and whales can transport large quantities of nutrients across ecosystem boundaries, greatly enriching recipient food webs. As many of these animals biomagnify contaminants, they can also focus pollutants at toxic levels. Seabirds arguably represent the most significant biovectors of nutrients and contaminants from the ocean to the land, given their sheer numbers and global distribution. However, long-term census data on seabirds are rare. Using palaeolimnological proxies, we show that a colony of Arctic seabirds has experienced climate-induced population increases in recent decades. We then document increasing concentrations of contaminants, including polychlorinated biphenyls and cadmium, in pond sediments that are linked to biotransport by seabirds. Our findings suggest that climate-related shifts in global seabird populations will have the unexpected consequence of restructuring coastal ecosystems.
PubMed ID
18945662 View in PubMed
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6 records – page 1 of 1.