Bering Sea ice at its lowest levels in 5,500 years: research

Winter ice in the Bering Sea, in the northern Pacific Ocean between Alaska and Russia, is at its lowest levels for 5,500 years, according to a study released on Wednesday.


Researchers analyzed vegetation that accumulated on the uninhabited island of St Matthew over the last five millennia.

They looked at variations in peat layers of oxygen atoms called isotopes 16 and 18, whose proportions over time correlate with atmospheric and oceanic changes and precipitation.

"It's a small island in the middle of the Bering Sea, and it's essentially been recording what's happening in the ocean and atmosphere around it," said Miriam Jones, the researcher who conducted the study at the University of Alaska and then at the US Geological Survey.

The scientists studied a single 1.45-meter peat core, taken from St Matthew in 2012, which represented 5,500 years of accumulation.

"What we've seen most recently is unprecedented in the last 5,500 years," writes Matthew Wooller, director of the Alaska Stable Isotope Facility, who participated in the analysis.

The ice in the Arctic and Bering Seas melts in summer and freezes anew in winter, but satellite observations only date back to 1979. ...
  AFP