Polar Bears in Peril
STORY: Right now, the Bering Sea between Alaska and Siberia is covered in several feet of ice that for nearly nine months joins the two continents. The ice forms first in the Arctic Ocean, then slowly creeps its way south through the Bering Strait.
It would seem an inhospitable place, yet life thrives here, and the key to it all is the ice itself. Everything from the tiniest plankton to the mighty polar bear depends on the Arctic's annual formation of sea ice. Vera Alexander is a biological oceanographer at the University of Alaska Fairbanks.
ALEXANDER: "The sea ice is the place where plants are produced in the Arctic ocean and is the base for the whole food chain. And of course the entire food chain on which the polar bear depends lives on these ice algae ultimately. That could be a food chain like amphipods eating the ice-algae, and polar cod eating the amphipods, and ringed seals eating the small fish, and polar bears eating the ringed seals."
Polar bears have evolved a special relationship with sea ice. After spending the summer months either fasting on land or waiting in the high Arctic's year-round ice pack, the bears are now able to venture across thousands of square miles of newly frozen sea in search of their favorite meal--ringed seals. Malcolm Ramsay is a polar bear biologist at the University of Saskatchewan.
RAMSAY: "Polar bears are highly specialized to feed on seals, primarily one species of seals, called the ringed seal. That seal is also intimately associated with sea ice. It requires sea ice to give birth to young. So if the sea ice were to disappear from a portion of the Arctic Ocean, it would, as far as we know, be it for the seals."
Ramsay is among a cadre of scientists who have begun sounding the alarm to what might happen to the Arctic food chain if predictions of a prolonged climate warming come to pass. In nearly 20 years of research, he's followed the movements of more than 2,000 polar bears. He believes that if the Arctic continues to warm, the sea ice bears depend on will melt and the delicately balanced food chain will fall apart.
RAMSAY: "I think in the long term if the global warming models that the climate modelers are proposing are correct, I would say it is distinctly possible that polar bears could disappear over most of their range in the next 75 years."
Vera Alexander says the polar bear's troubles are directly the result of global warming.
ALEXANDER: "Obviously it's attributable to warming, but whether we're talking about global warming in response to carbon dioxide and other gas input into the atmosphere, we can't say that for sure. It seems extremely likely to me."
If the Arctic climate is getting warmer, Malcolm Ramsay says the survival of polar bears may ultimately rest with a group of bears that live in the most remote regions of the Arctic.
RAMSAY: "We think there's a population of polar bears that live deep in the Arctic ocean that never come on land. They are completely unknown. Under worst case global warming scenarios they may be the last polar bears in existence. So we'd like to know something about them before we get into a more desperate situation."
Ramsay says there is evidence that such bears exist. He says a science expedition two years ago found tracks and saw several bears on the ice hundreds of miles from land.
OUTRO: For Arctic Science Journeys, this is Robert Hannon reporting from Fairbanks, Alaska.
Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks.
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