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Thursday, January 19, 2012

Inuit hunters buttress theory Arctic Ocean is approaching 'tipping point'

Inuit hunters buttress theory Arctic Ocean is approaching 'tipping point'

The Arctic Ocean might look like an isolated body at the top of the world, but several multi-year investigations have found deep interconnections with the Pacific and Atlantic oceans -- and new evidence that the polar sea may be poised to undergo a dramatic change in structure and life, senior climate oceanographer Eddy Carmack told the opening session of an annual marine science conference in Anchorage.

“Are we approaching a tipping point -- a new state?” Carmack said to several hundred scientists gathered at the Alaska Marine Science Symposium in the Hotel Captain Cook ballroom. “In the Arctic, the non-linear future is here.”
Carmack presented detailed oceanographic results from Canada’s Three Oceans project and a joint Canadian-American survey -- over the past five years, teams of scientists have sampled the sea at 600 different stations around the rim of North America. Among other things, they’ve found that the deep layers of Pacific and Atlantic waters north of Alaska are warming and that creatures at the bottom of the marine food chain are changing.
But disturbing changes noticed by two different Inuit hunters might be even more telling.
One man told Carmack that the ocean remained ice-free in a locale despite 50-below temperatures -- and the Arctic char disappeared from local lakes. Another man told Carmack that 69 of 70 seals he butchered over the winter had bellies full of krill -- a tiny shrimp-like crustacean -- instead of capelin, a common forage fish.
“He’d never seen that before,” Carmack said.
Carmack’s remarks came at the beginning of four days of lectures, workshops and reports at the annual Alaska Marine Science Symposium. More than 75 oceanographers, marine biologists, fisheries researchers and marine mammal specialists will give public talks at the Hotel Captain Cook Tuesday through Thursday. Some 270 scientific posters will be on display at the Dena’ina Convention Center, with receptions with the authors on Tuesday. Dozens of students will also be presenting their work. More details and abstracts are here.
The conference began with presentations about massive, epic investigations into the Bering Sea and Gulf of Alaska marine ecosystems by dozens of scientists spending thousands of hours at sea and in labs, as well as the new insights into the Arctic Ocean's deep connections with its sister oceans in each hemisphere. Early results in 2007 by Carmack's team showed the Arctic and nearby stretches of Atlantic and Pacific were already undergoing profound changes, and subsequent research has confirmed it.
“Today, change is under way,” Carmack wrote last month in Nature Geoscience, in a discussion titled “Cryosphere: Warmth from the deep.”
“Over the past few years, sea ice has been retreating and thinning. It has also become less tightly packed, allowing it to move more quickly in response to winds. The rates of these changes are faster than most climate models predict.”

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