[1] British Antarctic Survey, NERC, Cambridge CB3 0ET, England
[2] NASA, Goddard Space Flight Ctr, Hydrospher & Biospher Sci Lab, Greenbelt, MD 20771 USA
[3] CNR, Inst Prot Biochem, I-80131 Naples, Italy
[4] Alfred Wegener Inst Polar & Marine Res, D-27570 Bremerhaven, Germany
[5] Univ Maine, Sawyer Res Facil, Climate Change Inst, Orono, ME 04469 USA
[6] Univ Cambridge, Scott Polar Res Inst, Sci Comm Antarctic Res, Cambridge CB2 1ER, England