Günter Köck - Academia.edu (original) (raw)
Papers by Günter Köck
eco.mont (Journal on Protected Mountain Areas Research)
eco.mont (Journal on Protected Mountain Areas Research)
Environmental Toxicology and Chemistry
Science of The Total Environment
Environmental Toxicology and Chemistry
Non-anadromous forms of Arctic char (Salvelinus alpinus), those that are restricted to lakes and ... more Non-anadromous forms of Arctic char (Salvelinus alpinus), those that are restricted to lakes and rivers, typically have higher mercury (Hg) concentrations than anadromous forms, which migrate to and from the sea. Using tissue burden data from the literature and our own analyses, we performed a screening-level risk assessment of methylmercury (MeHg) for nonanadromous Arctic char. Our assessment included 1569 fish distributed across 83 sites. Site-specific mean total Hg concentrations in non-anadromous Arctic char muscle varied considerably from 0.01 to 1.13 mg/g wet weight, with 21% (17 of 83 sites) meeting or exceeding a threshold-effect level in fish of 0.33 mg/g wet weight, and 13% (11 of 83 sites) meeting or exceeding a threshold-effect level in fish of 0.5 mg/g wet weight. Of the sites in exceedance of the 0.33-mg/g threshold, 7 were located in Greenland and 10 in Canada (Labrador, Nunavut, and Yukon). All but one of these sites were located in interfrost or permafrost biomes. Maximum total Hg concentrations exceeded 0.33 mg/g wet weight at 53% of sites (40 of the 75 sites with available maximum Hg values), and exceeded 0.5 mg/g wet weight at 27% (20 of 75 sites). Collectively, these results indicate that certain populations of non-anadromous Arctic char located mainly in interfrost and permafrost regions may be at risk for MeHg toxicity. This approach provides a simple statistical assessment of MeHg risk to non-anadromous Arctic char, and does not indicate actual effects. We highlight the need for studies that evaluate the potential toxic effects of MeHg in nonanadromous Arctic char, as well as those that aid in the development of a MeHg toxic-effect threshold specific to this species of fish.
Environmental Science & Technology
Temporal trends and climate related parameters affecting the fate of legacy persistent organic po... more Temporal trends and climate related parameters affecting the fate of legacy persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were examined in landlocked Arctic char from four lakes in the Canadian Arctic. Among biological parameters, lipid content was a key factor explaining the concentration of most POPs in Arctic char. Legacy PCBs and OCPs generally showed declining trends of concentrations in Arctic char, consistent with past restriction on uses and emissions of POPs. However, increases in lake primary productivity (measured as chlorophyll a) exerted a dilution effect on POPs concentrations in Arctic char. Concentrations of POPs in char from the last two decades were positively correlated with interannual variations of the North Atlantic Oscillation (NAO). Higher concentrations of POPs in Arctic char were observed in 3 of the 4 lakes during positive NAO phases. This, together with increasing local Arctic temperatures, could lead to increases on POPs concentrations in char from remote Arctic Lakes in future decades. Also, if there are nearby secondary sources as may be the case for Resolute Lake, located near an airport where increasing levels were found for hexachlorobenzene and toxaphene, probably due to the mobilization from secondary sources in soils.
Nature communications, Jan 29, 2018
Using a whole-watershed approach and a combination of historical, contemporary, modeled and paleo... more 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, limnologi...
eco.mont (Journal on Protected Mountain Areas Research)
During the past four decades UNESCO's Man and the Biosphere (MAB) Programme and its World Network... more During the past four decades UNESCO's Man and the Biosphere (MAB) Programme and its World Network of Biosphere Reserves repeatedly went through significant adaptation and modernization processes.
eco.mont (Journal on Protected Mountain Areas Research)
The EuroMAB Network includes all European and North-American member states which participate in U... more The EuroMAB Network includes all European and North-American member states which participate in UNESCO´s Man and the Biosphere (MAB) Programme and its World Network of Biosphere Reserves (WNBR). EuroMAB is the largest and oldest of the nine regional and interregional MAB Networks. It is made up of 36 countries, including Canada and the USA, and includes 302 biosphere reserves (BRs). Bringing together almost half of the total WNBR sites, the EuroMAB Network is a platform for sharing knowledge, know-how and experience of sustainable development, as well as a collective tool for supporting sustainable development practices among BR coordinators, scientists and MAB 1DWLRQDO &RPPLWWHHV 6LQFH WKH ILUVW PHHWLQJ LQ LQ ÿHVNp %XGrMRYLFH &]HFK 5HSXEOLF WKH 0$% 1DWLRQDO &RPmittees and BR coordinators of EuroMAB have met nearly every two years. EuroMAB conferences have been held in
Environmental Pollution, 2016
We sampled landlocked Arctic char (Salvelinus alpinus) from four lakes (Small, 9-Mile, North, Ami... more We sampled landlocked Arctic char (Salvelinus alpinus) from four lakes (Small, 9-Mile, North, Amituk) in the Canadian High Arctic that span a gradient of mercury contamination. Metals (Hg, Se, Tl, and Fe) were measured in char tissues to determine their relationships with health indices (relative condition factor and hepatosomatic index), stable nitrogen isotope ratios, and liver histology. A subcellular partitioning procedure was employed to determine how metals were distributed between potentially sensitive and detoxified compartments of Arctic char livers from a low- and high-mercury lake (Small Lake and Amituk Lake, respectively). Differences in health indices and metal concentrations among char populations were likely related to differences in feeding ecology. Concentrations of Hg, Se, and Tl were highest in the livers of Amituk char, whereas concentrations of Fe were highest in Small and 9-Mile char. At the subcellular level we found that although Amituk char had higher concentrations of Tl in whole liver than Small Lake char, they maintained a greater proportion of this metal in detoxified fractions, suggesting an attempt at detoxification. Mercury was found mainly in potentially sensitive fractions of both Small and Amituk Lake char, indicating that Arctic char are not effectively detoxifying this metal. Histological changes in char livers, mainly in the form of melano-macrophage aggregates and hepatic fibrosis, could be linked to the concentrations and subcellular distributions of essential or non-essential metals.
eco.mont (Journal on Protected Mountain Areas Research)
eco.mont (Journal on Protected Mountain Areas Research)
Environmental Toxicology and Chemistry
Science of The Total Environment
Environmental Toxicology and Chemistry
Non-anadromous forms of Arctic char (Salvelinus alpinus), those that are restricted to lakes and ... more Non-anadromous forms of Arctic char (Salvelinus alpinus), those that are restricted to lakes and rivers, typically have higher mercury (Hg) concentrations than anadromous forms, which migrate to and from the sea. Using tissue burden data from the literature and our own analyses, we performed a screening-level risk assessment of methylmercury (MeHg) for nonanadromous Arctic char. Our assessment included 1569 fish distributed across 83 sites. Site-specific mean total Hg concentrations in non-anadromous Arctic char muscle varied considerably from 0.01 to 1.13 mg/g wet weight, with 21% (17 of 83 sites) meeting or exceeding a threshold-effect level in fish of 0.33 mg/g wet weight, and 13% (11 of 83 sites) meeting or exceeding a threshold-effect level in fish of 0.5 mg/g wet weight. Of the sites in exceedance of the 0.33-mg/g threshold, 7 were located in Greenland and 10 in Canada (Labrador, Nunavut, and Yukon). All but one of these sites were located in interfrost or permafrost biomes. Maximum total Hg concentrations exceeded 0.33 mg/g wet weight at 53% of sites (40 of the 75 sites with available maximum Hg values), and exceeded 0.5 mg/g wet weight at 27% (20 of 75 sites). Collectively, these results indicate that certain populations of non-anadromous Arctic char located mainly in interfrost and permafrost regions may be at risk for MeHg toxicity. This approach provides a simple statistical assessment of MeHg risk to non-anadromous Arctic char, and does not indicate actual effects. We highlight the need for studies that evaluate the potential toxic effects of MeHg in nonanadromous Arctic char, as well as those that aid in the development of a MeHg toxic-effect threshold specific to this species of fish.
Environmental Science & Technology
Temporal trends and climate related parameters affecting the fate of legacy persistent organic po... more Temporal trends and climate related parameters affecting the fate of legacy persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were examined in landlocked Arctic char from four lakes in the Canadian Arctic. Among biological parameters, lipid content was a key factor explaining the concentration of most POPs in Arctic char. Legacy PCBs and OCPs generally showed declining trends of concentrations in Arctic char, consistent with past restriction on uses and emissions of POPs. However, increases in lake primary productivity (measured as chlorophyll a) exerted a dilution effect on POPs concentrations in Arctic char. Concentrations of POPs in char from the last two decades were positively correlated with interannual variations of the North Atlantic Oscillation (NAO). Higher concentrations of POPs in Arctic char were observed in 3 of the 4 lakes during positive NAO phases. This, together with increasing local Arctic temperatures, could lead to increases on POPs concentrations in char from remote Arctic Lakes in future decades. Also, if there are nearby secondary sources as may be the case for Resolute Lake, located near an airport where increasing levels were found for hexachlorobenzene and toxaphene, probably due to the mobilization from secondary sources in soils.
Nature communications, Jan 29, 2018
Using a whole-watershed approach and a combination of historical, contemporary, modeled and paleo... more 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, limnologi...
eco.mont (Journal on Protected Mountain Areas Research)
During the past four decades UNESCO's Man and the Biosphere (MAB) Programme and its World Network... more During the past four decades UNESCO's Man and the Biosphere (MAB) Programme and its World Network of Biosphere Reserves repeatedly went through significant adaptation and modernization processes.
eco.mont (Journal on Protected Mountain Areas Research)
The EuroMAB Network includes all European and North-American member states which participate in U... more The EuroMAB Network includes all European and North-American member states which participate in UNESCO´s Man and the Biosphere (MAB) Programme and its World Network of Biosphere Reserves (WNBR). EuroMAB is the largest and oldest of the nine regional and interregional MAB Networks. It is made up of 36 countries, including Canada and the USA, and includes 302 biosphere reserves (BRs). Bringing together almost half of the total WNBR sites, the EuroMAB Network is a platform for sharing knowledge, know-how and experience of sustainable development, as well as a collective tool for supporting sustainable development practices among BR coordinators, scientists and MAB 1DWLRQDO &RPPLWWHHV 6LQFH WKH ILUVW PHHWLQJ LQ LQ ÿHVNp %XGrMRYLFH &]HFK 5HSXEOLF WKH 0$% 1DWLRQDO &RPmittees and BR coordinators of EuroMAB have met nearly every two years. EuroMAB conferences have been held in
Environmental Pollution, 2016
We sampled landlocked Arctic char (Salvelinus alpinus) from four lakes (Small, 9-Mile, North, Ami... more We sampled landlocked Arctic char (Salvelinus alpinus) from four lakes (Small, 9-Mile, North, Amituk) in the Canadian High Arctic that span a gradient of mercury contamination. Metals (Hg, Se, Tl, and Fe) were measured in char tissues to determine their relationships with health indices (relative condition factor and hepatosomatic index), stable nitrogen isotope ratios, and liver histology. A subcellular partitioning procedure was employed to determine how metals were distributed between potentially sensitive and detoxified compartments of Arctic char livers from a low- and high-mercury lake (Small Lake and Amituk Lake, respectively). Differences in health indices and metal concentrations among char populations were likely related to differences in feeding ecology. Concentrations of Hg, Se, and Tl were highest in the livers of Amituk char, whereas concentrations of Fe were highest in Small and 9-Mile char. At the subcellular level we found that although Amituk char had higher concentrations of Tl in whole liver than Small Lake char, they maintained a greater proportion of this metal in detoxified fractions, suggesting an attempt at detoxification. Mercury was found mainly in potentially sensitive fractions of both Small and Amituk Lake char, indicating that Arctic char are not effectively detoxifying this metal. Histological changes in char livers, mainly in the form of melano-macrophage aggregates and hepatic fibrosis, could be linked to the concentrations and subcellular distributions of essential or non-essential metals.