The East Siberian Arctic Shelf: towards further assessment of permafrost-related methane fluxes and role of sea ice.
Sustained release of methane (CH(4)) to the atmosphere from thawing Arctic permafrost may be a positive and significant feedback to climate warming. Atmospheric venting of CH(4) from the East Siberian Arctic Shelf (ESAS) was recently reported to be on par with flux from the Arctic tundra; however, the future scale of these releases remains unclear. Here, based on results of our latest observations, we show that CH(4) emissions from this shelf are likely to be determined by the state of subsea permafrost degradation. We observed CH(4) emissions from two previously understudied areas of the ESAS: the outer shelf, where subsea permafrost is predicted to be discontinuous or mostly degraded due to long submergence by seawater, and the near shore area, where deep/open taliks presumably form due to combined heating effects of seawater, river run-off, geothermal flux and pre-existing thermokarst. CH(4) emissions from these areas emerge from largely thawed sediments via strong flare-like ebullition, producing fluxes that are orders of magnitude greater than fluxes observed in background areas underlain by largely frozen sediments. We suggest that progression of subsea permafrost thawing and decrease in ice extent could result in a significant increase in CH(4) emissions from the ESAS.
International Arctic Research Center, University of Alaska Fairbanks, Akasofu Building, Fairbanks, AK 99775-7320, USA Tomsk Polytechnic University, Institute of Natural Resources, Geology and Mineral Exploration, 30 Prospect Lenina, Tomsk, Russia nshakhov@iarc.uaf.edu.
Natalia
N
Shakhova
International Arctic Research Center, University of Alaska Fairbanks, Akasofu Building, Fairbanks, AK 99775-7320, USA Tomsk Polytechnic University, Institute of Natural Resources, Geology and Mineral Exploration, 30 Prospect Lenina, Tomsk, Russia Russian Academy of Sciences, Pacific Oceanological Institute, 43 Baltiiskaya Street, Vladivostok 690041, Russia.
Igor
I
Semiletov
Russian Academy of Sciences, Institute of Chemistry, 159, 100-Let Vladivostok Prospect, Vladivostok 690022, Russia.
Valentin
V
Sergienko
Russian Academy of Sciences, P.P. Shirshov Oceanological Institute, 36 Nahimovski Prospect, Moscow 117997, Russia.
Leopold
L
Lobkovsky
Russian Academy of Sciences, Institute on Laser and Information Technologies, 2 Pionerskaya Street, Troitsk 142092, Russia.
Vladimir
V
Yusupov
Russian Academy of Sciences, Pacific Oceanological Institute, 43 Baltiiskaya Street, Vladivostok 690041, Russia.
Anatoly
A
Salyuk
Russian Academy of Sciences, Pacific Oceanological Institute, 43 Baltiiskaya Street, Vladivostok 690041, Russia.
Alexander
A
Salomatin
Russian Academy of Sciences, Pacific Oceanological Institute, 43 Baltiiskaya Street, Vladivostok 690041, Russia.
Denis
D
Chernykh
Russian Academy of Sciences, Pacific Oceanological Institute, 43 Baltiiskaya Street, Vladivostok 690041, Russia.
Denis
D
Kosmach
International Arctic Research Center, University of Alaska Fairbanks, Akasofu Building, Fairbanks, AK 99775-7320, USA.
Gleb
G
Panteleev
University of Alaska Fairbanks, Geophysical Institute, Snow, Ice and Permafrost, PO Box 757320, Fairbanks, AK 99775-7320, USA.
Dmitry
D
Nicolsky
Department of Marine Science, University of Georgia Atlanta, 3475 Lenox Road, NE Suite 300, Atlanta, GA 30326-3228, USA.
Vladimir
V
Samarkin
Department of Marine Science, University of Georgia Atlanta, 3475 Lenox Road, NE Suite 300, Atlanta, GA 30326-3228, USA.
Samantha
S
Joye
Russian Academy of Sciences, Pacific Oceanological Institute, 43 Baltiiskaya Street, Vladivostok 690041, Russia.
Alexander
A
Charkin
Russian Academy of Sciences, Pacific Oceanological Institute, 43 Baltiiskaya Street, Vladivostok 690041, Russia.
Oleg
O
Dudarev
Russian Academy of Sciences, P.P. Shirshov Oceanological Institute, 36 Nahimovski Prospect, Moscow 117997, Russia.
Alexander
A
Meluzov
Department of Applied Environmental Science and Bolin Centre for Climate Research, Stockholm University, Stockholm 10691, Sweden.
Orjan
O
Gustafsson
East Siberian Arctic Shelf; methane emissions; sea ice; subsea permafrost