[1] Univ Alaska, Int Arctic Res Ctr, Fairbanks, AK 99775 USA
[2] Russian Acad Sci, Pacific Oceanol Inst, Far Eastern Branch, Vladivostok 690022, Russia
[3] Stockholm Univ, Dept Appl Environm Sci, S-10691 Stockholm, Sweden
[4] Stockholm Univ, Bert Bolin Ctr Climate Res, S-10691 Stockholm, Sweden