METHANE AND CARBON DIOXIDE IN THE SURFACE WATER OFF SAKHALIN ISLAND IN THE SEA OF OKHOTSK

Abstract

The Sea of Okhotsk is the 6th largest marginal sea in the world. It is known as the origin of North Pacific Intermediate Water (NPIW), which plays an important role of the entire circulation of the Pacific (Talley, 1991

Warner et al., 1996). Methane and carbon dioxide are important green house gases. In order to understand the biogeochemical cycle of green house gases, it is essential to understand the source and sink of the gases. Especially the source and sink of methane are poorly studied. In general, the methane supply from the sea into the atmosphere is relatively small that is, about 0.005 &#8211

3% of total gas supply (Conrad and Seiler, 1988

Cicerone and Oremland, 1988

Bange et al., 1994). However, the Sea of Okhotsk is known as one of important source of methane (Yoshida et al, 2004). The study of methane in the Sea of Okhotsk was focused on the distribution in the deep layer related the gas hydrate which is widely distributed on the bottom of the Sea of Okhotsk.(Ginburg et al., 1993

Cranston et al., 1994

Lammers et al., 1995

Shakirov et al., 2004). NPIW is known as one of important sink of atmospheric CO2 (Watanabe et al., 1996).The purpose of this study is understanding of the horizontal distribution of methane and carbon dioxide in the surface seawater off Sakhalin Island in the Sea of Okhotsk.