Antaletriangle
04-04-2009, 01:42 PM
http://www.enn.com/top_stories/spotlight/39583
Every summer, seal hunters in the village of Ulukhaktok in Canada’s Northwest Territories carve out small pieces of muscle from ringed seals during their annual subsistence hunt. As part of their collaboration with Arctic researchers, they carefully bag the tissue samples, draw blood, and measure each seal.
After more than 30 years of monitoring the seals, the researchers have noticed a disturbing pattern: levels of the dangerous metal mercury in the seals are connected to the state of sea ice on the ocean. The new research, published in ES&T, reveals that more mercury may be spiraling up the food chain as sea ice disappears.
“The trend now in the loss of sea ice suggests that mercury in ringed seals will increase over time,”� says Gary Stern, a study coauthor from the University of Manitoba (Canada). His team, along with colleagues from Fisheries and Oceans Canada, measured mercury levels in ringed seals collected from 1973 to 2007 and related the levels to the length of the summer ice-free season in the seals’ habitat.
The Arctic environment already contains more mercury than animals there can take up, Stern explains. However, a shifting climate could result in ecosystems converting the mercury into highly toxic forms that biomagnify up the food chain.
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The researchers found that mercury concentrations in seals were higher in years when the ice-free season was either very long or very short. The researchers think this is related to the seals’ food supplies. Cod are the most-mercury-contaminated food that ringed seals eat, so the seals’ summer mercury levels depend largely on how much cod the seals ate during their previous fall and winter hunting season. Older cod are the most contaminated, because the metal accumulates over time.
The researchers think that a longer ice-free season creates milder conditions that favor cod growth. So in years with less sea ice, seals have a longer ice-free period in which to catch cod, plus there may be more cod to eat. Alternatively, when sea ice stays frozen for a long time, young cod may have a harder time surviving the winter, leaving a greater proportion of older and more contaminated cod as a food supply.
This interpretation is “interesting and challenging, but highly speculative,” says Louis Fortier of the University of Laval (Canada). Fortier is a colleague of Stern’s but is not associated with the new study. Further work is needed to verify actual mercury levels in the seals’ food supplies, Fortier notes, but “if confirmed, the proposed link between sea-ice dynamics and the transfer of mercury in the food web, up to polar bear and man, would give a measure of the convoluted ways by which climate change can impact ecosystem services in the Arctic and elsewhere on the planet.”
The Arctic Ocean has lost more than 50,000 square kilometers of ice per year since 2002 and has been losing ice overall since the 1950s. Not only is the area covered by sea ice smaller, but the remaining ice is thinner and younger because less ice is able to persist over summer. In addition, the region is seeing larger areas of open water called flaw leads, which form when sea ice pulls away from ice attached to land.
“We’re seeing more and more, and larger and larger, flaw leads forming. It’s changing the ecology of the Arctic Ocean quite significantly. It’s changing everything,” Stern says. Open water receives more light, so more phytoplankton grow, and this fuels an abundance of fish and small animals, which in turn draw large mammals such as ringed seals and walruses. It’s possible that more growth could draw more mercury contamination from the ocean, he says.
Although mercury levels are of concern for the health of seals and of people who consume them through subsistence hunting, Stern says that the benefits of a traditional subsistence diet “far outweigh the risks” for native communities. His team suggests continued monitoring of mercury in seals, beluga whales, and other marine mammals that could be affected by shrinking sea ice.
“My guess is that under climate change, the mercury cycle will get cranked up,” which could lead to more food items exceeding health thresholds for mercury exposure, says Robie Macdonald, an oceanographer at Fisheries and Oceans Canada not affiliated with the study. “When you disturb a system, it has to get itself back to some new dynamic, and usually in that process is when you have the release of metals.”
http://sacramentofordemocracy.org/?q=node/view/28262
Petition below.
http://www.thepetitionsite.com/takeaction/717129956
Mercury Levels in Seals Rising - Reverse the Trend
Target: Interior Secretary Ken Salazar
Global warming is changing the ecology of the Arctic Ocean - and the effects on the inhabitants of the Arctic are just starting to come to light. A just-released research report links vanishing sea ice to a shocking rise in mercury levels in ringed seals.
Cod are a very mercury-contaminated species - and a favorite of ringed seals during the ice-free season. Because the ice-free season is becoming longer and longer due to global warming, researchers say, the feeding season for ringed seals is also becoming longer - and as a consequence, the seals are taking in too much mercury.
The mercury contamination will only get worse for the Arctic ringed seal unless we start to seriously address global warming! More research is needed to see just how the transfer of mercury in the food web is being affected by global warming. Urge Secretary of the Interior Ken Salazar to ensure his department puts resources behind investigating the impact of global warming on seals and other marine life.
deadline: Ongoing...
goal: 10,000
325
signatures!
Dear Secretary Salazar,
I am writing today after reading about recent research in the journal Environment, Science and Technology that linked vanishing sea ice in the Arctic to a shocking rise in mercury levels in ringed seals. Please put your department's resources behind investigating the impact of global warming on seals and other marine life.
Cod are a very mercury-contaminated species of fish - and a favorite of ringed seals during the ice-free season. Because the ice-free season has been becoming longer and longer due to global warming, researchers say, the feeding season for ringed seals has become longer - and as a consequence, the seals are taking in too much mercury.
The mercury contamination will only get worse for the Arctic ringed seal unless we start addressing global warming immediately! More research is needed to see just how the transfer of mercury in the food web is being affected by global warming.
[Your comment here]
Thank you for speaking out for the ringed seal and other marine life.
Sincerely,
[Your name here]
Every summer, seal hunters in the village of Ulukhaktok in Canada’s Northwest Territories carve out small pieces of muscle from ringed seals during their annual subsistence hunt. As part of their collaboration with Arctic researchers, they carefully bag the tissue samples, draw blood, and measure each seal.
After more than 30 years of monitoring the seals, the researchers have noticed a disturbing pattern: levels of the dangerous metal mercury in the seals are connected to the state of sea ice on the ocean. The new research, published in ES&T, reveals that more mercury may be spiraling up the food chain as sea ice disappears.
“The trend now in the loss of sea ice suggests that mercury in ringed seals will increase over time,”� says Gary Stern, a study coauthor from the University of Manitoba (Canada). His team, along with colleagues from Fisheries and Oceans Canada, measured mercury levels in ringed seals collected from 1973 to 2007 and related the levels to the length of the summer ice-free season in the seals’ habitat.
The Arctic environment already contains more mercury than animals there can take up, Stern explains. However, a shifting climate could result in ecosystems converting the mercury into highly toxic forms that biomagnify up the food chain.
ADVERTISEMENT
The researchers found that mercury concentrations in seals were higher in years when the ice-free season was either very long or very short. The researchers think this is related to the seals’ food supplies. Cod are the most-mercury-contaminated food that ringed seals eat, so the seals’ summer mercury levels depend largely on how much cod the seals ate during their previous fall and winter hunting season. Older cod are the most contaminated, because the metal accumulates over time.
The researchers think that a longer ice-free season creates milder conditions that favor cod growth. So in years with less sea ice, seals have a longer ice-free period in which to catch cod, plus there may be more cod to eat. Alternatively, when sea ice stays frozen for a long time, young cod may have a harder time surviving the winter, leaving a greater proportion of older and more contaminated cod as a food supply.
This interpretation is “interesting and challenging, but highly speculative,” says Louis Fortier of the University of Laval (Canada). Fortier is a colleague of Stern’s but is not associated with the new study. Further work is needed to verify actual mercury levels in the seals’ food supplies, Fortier notes, but “if confirmed, the proposed link between sea-ice dynamics and the transfer of mercury in the food web, up to polar bear and man, would give a measure of the convoluted ways by which climate change can impact ecosystem services in the Arctic and elsewhere on the planet.”
The Arctic Ocean has lost more than 50,000 square kilometers of ice per year since 2002 and has been losing ice overall since the 1950s. Not only is the area covered by sea ice smaller, but the remaining ice is thinner and younger because less ice is able to persist over summer. In addition, the region is seeing larger areas of open water called flaw leads, which form when sea ice pulls away from ice attached to land.
“We’re seeing more and more, and larger and larger, flaw leads forming. It’s changing the ecology of the Arctic Ocean quite significantly. It’s changing everything,” Stern says. Open water receives more light, so more phytoplankton grow, and this fuels an abundance of fish and small animals, which in turn draw large mammals such as ringed seals and walruses. It’s possible that more growth could draw more mercury contamination from the ocean, he says.
Although mercury levels are of concern for the health of seals and of people who consume them through subsistence hunting, Stern says that the benefits of a traditional subsistence diet “far outweigh the risks” for native communities. His team suggests continued monitoring of mercury in seals, beluga whales, and other marine mammals that could be affected by shrinking sea ice.
“My guess is that under climate change, the mercury cycle will get cranked up,” which could lead to more food items exceeding health thresholds for mercury exposure, says Robie Macdonald, an oceanographer at Fisheries and Oceans Canada not affiliated with the study. “When you disturb a system, it has to get itself back to some new dynamic, and usually in that process is when you have the release of metals.”
http://sacramentofordemocracy.org/?q=node/view/28262
Petition below.
http://www.thepetitionsite.com/takeaction/717129956
Mercury Levels in Seals Rising - Reverse the Trend
Target: Interior Secretary Ken Salazar
Global warming is changing the ecology of the Arctic Ocean - and the effects on the inhabitants of the Arctic are just starting to come to light. A just-released research report links vanishing sea ice to a shocking rise in mercury levels in ringed seals.
Cod are a very mercury-contaminated species - and a favorite of ringed seals during the ice-free season. Because the ice-free season is becoming longer and longer due to global warming, researchers say, the feeding season for ringed seals is also becoming longer - and as a consequence, the seals are taking in too much mercury.
The mercury contamination will only get worse for the Arctic ringed seal unless we start to seriously address global warming! More research is needed to see just how the transfer of mercury in the food web is being affected by global warming. Urge Secretary of the Interior Ken Salazar to ensure his department puts resources behind investigating the impact of global warming on seals and other marine life.
deadline: Ongoing...
goal: 10,000
325
signatures!
Dear Secretary Salazar,
I am writing today after reading about recent research in the journal Environment, Science and Technology that linked vanishing sea ice in the Arctic to a shocking rise in mercury levels in ringed seals. Please put your department's resources behind investigating the impact of global warming on seals and other marine life.
Cod are a very mercury-contaminated species of fish - and a favorite of ringed seals during the ice-free season. Because the ice-free season has been becoming longer and longer due to global warming, researchers say, the feeding season for ringed seals has become longer - and as a consequence, the seals are taking in too much mercury.
The mercury contamination will only get worse for the Arctic ringed seal unless we start addressing global warming immediately! More research is needed to see just how the transfer of mercury in the food web is being affected by global warming.
[Your comment here]
Thank you for speaking out for the ringed seal and other marine life.
Sincerely,
[Your name here]