HR: 0800h
AN: OS51B-0559    [Abstracts]
TI: C-14 "reservoir-effect" as a tracer of deep carbon flux in the Subarctic and Arctic Seas
AU: * Salyuk, A N
EM: san@poi.dvo.ru
AF: Pacific oceanological institute FEB RAS, 43 Baltiyskaya Str, Vladivostok, 690041 Russian Federation
AB: The Northern part of Sakhalin slope and adjacent region of the Sea of Okhotsk is known as an area of high productivity and active gas (CH4 and others) and cold fluid venting. This area was studied over the last 10 years in framework of Joint Russian-German project KOMEX. Strong carbon sources from Northern Sakhalin shelf and slope and Amur River were well documented. Meanwhile the deep carbon flux in such areas as Derugin Basin of the Sea of Okhotsk is still poorly investigated. Our study of water properties showed correlation between silica and C-14. The highest Si concentration 265 uM/kg was found in the Derugin Basin. Nature of this Si increase is similar to process of ageing, where Si dissolution and disintegration of C-14 grow in time. Reservoir-effect correction of C-14 age up to ~1800 years and more is possible in all range of silica concentrations. In the same time expected "hydrologic age" of deep waters, estimated on the basis of hydrologic properties is much lower - not more then 100-200 years. We suggest that aged carbon (with proportionally high Si) was added to deep carbon reservoir. This old carbon most likely is supplied with deep sub bottom cold fluids observed in different parts of Derugin basin. The difference between the observed and "hydrologic" deep water age gives possibility to estimate the amount of dead carbon. In arctic seas additional source of surface sediment old carbon should be considered. It would also increase the observed water age, which has probably different relationship with silica and some other hydro chemical water properties.
DE: 1041 Stable isotope geochemistry (0454, 4870)
DE: 4200 OCEANOGRAPHY: GENERAL
DE: 4806 Carbon cycling (0428)
DE: 4835 Marine inorganic chemistry (1050)
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005