Oxygen isotopic composition and its application to the study of tracing oceanographical process in Bering Sea and Chukchi Sea

In this paper, the 18 O distribution of surface water from the central sea areas of the Bering Sea and the Chukchi Sea was studied. The δ 18 O value of surface water from the Bering Sea is averagely -0.5‰; the δ 18 O contents of the Chukchi Sea are distributionally lower in northeast and higher in southwest; the δ 18 O value at the margin of Canadian Basin is -2.8‰, and averagely -0.8‰ in the southern area of the Chukchi Sea. The δ 18 O vertical distribution in some deep water stations from the Chukchi Sea and the Bering Sea is also studied. In the southern margin of Canadian Basin, the δ 18 O value is -2‰ -3‰ for surface layer and rises to 0 at 100 m depth layer. In the Bering Sea, the δ 18 O is about -0.5‰ for surface layer and increases to 0 at the depth of 300 m. The NO tracer can reflect obviously three water masses vertically distributed in the central Bering Sea: the upper Bering water mass, the middle Bering water mass and the deep Pacific water mass. The distributive ranges of NO and temperature for the various water masses are T<7℃, NO>780 μmol/dm 3 and T≥7℃, NO>650 μmol/dm 3 for upper Bering water mass, T<4℃, 550<NO<780 μmol/dm 3 for middle Bering water mass, and T<4℃, 330<NO<550 μmol/dm 3 for deep Pacific water mass. It is found from δ 18 O-S relation diagram and δ 18 O vertical profiles that the δ 18 O is about +0.3‰ from halocline layer till sea bottom. Its isotopic characteristics are the same as the Atlantic water, showing that the sea water comes from the north Atlantic. The freshwater end member of the Chukchi Sea in the survey period is also explored.