HR: 1340h
AN: B53A-0917 [Abstracts]
TI: Methane release and surface sediment environment in the East Siberian Arctic shelf.
AU: * Kosmach, D
EM: den-kosmach@mail.ru
AF: VI Il'ichov Pacific Oceanological Institute/Far Eastern Branch of russian Academy of
Sciences, 43 Baltic Street, Vl;adivostok, 690041, Russian Federation
AU: Shakhova, N
EM: nshakhov@iarc.uaf.edu
AF: VI Il'ichov Pacific Oceanological Institute/Far Eastern Branch of russian Academy of
Sciences, 43 Baltic Street, Vl;adivostok, 690041, Russian Federation
AU: Shakhova, N
EM: nshakhov@iarc.uaf.edu
AF: International Arctic Research Center/University Alaska Fairbanks, Akasofu Building,
Fairbanks, AK 99775, United States
AU: Semiletov, I
EM: igorsm@iarc.uaf.edu
AF: VI Il'ichov Pacific Oceanological Institute/Far Eastern Branch of russian Academy of
Sciences, 43 Baltic Street, Vl;adivostok, 690041, Russian Federation
AU: Semiletov, I
EM: igorsm@iarc.uaf.edu
AF: International Arctic Research Center/University Alaska Fairbanks, Akasofu Building,
Fairbanks, AK 99775, United States
AU: Dudarev, O
EM: dudarev@poi.dvo.ru
AF: VI Il'ichov Pacific Oceanological Institute/Far Eastern Branch of russian Academy of
Sciences, 43 Baltic Street, Vl;adivostok, 690041, Russian Federation
AB:
Arctic shallow seabed sediments have received little attention with regard to their contribution to the global carbon
budget and, particularly, the marine methane (or CH4) budget, because of their small areal extent (Archer, 2006;
Shakhova and Semiletov, 2007). Furthermore, the low temperatures that characterize these sediments are not
considered conducive to methanogenesis, though psychrophilic methanogens may exist (Rivkina et al., 2006). In
case of the Siberian Arctic shelf, shallow sediments have not been considered a methane source to the
hydrosphere or to the atmosphere because submarine (offshore) permafrost acts as a impermeable lid,
preventing methane escape. However, recent data from the east Siberian Arctic shelf (ESAS) during 2003-2005,
showed extreme CH4 super-saturation of surface waters (up to 4400% saturation), implying that high air-to-sea
fluxes occur at times (Shakhova et al., 2005, 2007ab). Understanding the factors generating the high
concentrations of methane in the waters of East Siberian shelf requires additional and detail research efforts.
Thus in summer of 2005 we investigated the methane in ESAS surface sediment and sea water at 127 locations.
Methane concentrations were determined on site with GC-FID head-space measurements. Spatial correlation
among methane anomalies and fault zones has been found, while it was no correlation with sediment organic
carbon content and mineralogical composition.
DE: 0428 Carbon cycling (4806)
DE: 0490 Trace gases
DE: 4806 Carbon cycling (0428)
DE: 4820 Gases
DE: 4863 Sedimentation (1861)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting