Arctic food web, harming the area's people. We may be next.
April 30, 2008 | ARCTIC OCEAN -- Over 300 miles north of the Arctic Circle, in the polar dark of a December morning, University of Manitoba Ph.D. student Jesse Carrie is out on the frozen Beaufort Sea, collecting ice samples to measure for mercury and pesticides. Lowered by crane from the deck of the icebreaking research vessel the CCGS Amundsen, and accompanied by a rifle bearer who keeps watch for polar bears, Carrie extracts ice cores and vials of frigid water. Carrie is part of a $40 million International Polar Year scientific expedition, the first ever to spend the winter moving through sea ice north of the Arctic Circle. The expedition's labor-intensive work is essential to understanding the impacts of global warming.
As the Amundsen cuts through ice across the top of the globe, Carrie and his fellow researchers are uncovering evidence of a disturbing fallout of climate change. They are finding toxic contaminants, some at remarkably high levels, accumulating in this remote and visually pristine environment. Although there are no industrial sources in the Arctic, residents of the Far North have some of the world's highest levels of mercury exposure, some well above what the World Health Organization considers safe. High levels of mercury -- a powerful neurotoxin -- are being found in Arctic marine wildlife, including ringed seals and beluga whales, both staples of the traditional Northern diet. Levels in Arctic beluga have increased markedly in recent years.
When coal is burned in power plants in the U.S., China and elsewhere, mercury is released into the atmosphere. Airborne, mercury can travel great distances before settling to the ground, or into lakes, rivers and oceans. Air and ocean currents, propelled by weather patterns and storm systems, sweep the mercury north. But the recent increases in Arctic mercury outpace and cannot be explained by smokestack emissions alone, says Gary A. Stern, a senior scientist with Canada's Department of Fisheries and Oceans, professor at the University of Manitoba and co-leader of the Amundsen expedition. Rather, signs point to global warming and other disruptive impacts of climate change.
As temperatures rise, causing sea ice, permafrost and snow to melt, the mercury that had been frozen in place is now being released, causing exposure up and down the food web. "Climate change alters exposure in the north and increases the system's vulnerability," says Robie Macdonald, a research scientist with Canada's Department of Fisheries and Oceans.
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