Abstract:

In this paper, the ¹⁸O distribution of surface water from the central sea areas of the Bering Sea and the Chukchi Sea was studied. The δ¹⁸O value of surface water from the Bering Sea is averagely -0.5‰; the δ¹⁸O contents of the Chukchi Sea are distributionally lower in northeast and higher in southwest; the δ¹⁸O value at the margin of Canadian Basin is -2.8‰, and averagely -0.8‰ in the southern area of the Chukchi Sea. The δ¹⁸O 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 δ¹⁸O value is -2‰ - -3‰ for surface layer and rises to 0 at 100 m depth layer. In the Bering Sea, the δ¹⁸O 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/dm³ and T≥7℃, NO>650 μmol/dm³ for upper Bering water mass, T<4℃, 550<NO<780 μmol/dm³ for middle Bering water mass, and T<4℃, 330<NO<550 μmol/dm³ for deep Pacific water mass. It is found from δ¹⁸O-S relation diagram and δ¹⁸O vertical profiles that the δ¹⁸O 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.

Key words: Chukchi Sea, Bering Sea, ¹⁸O, water masses, sea-ice melting water