THE DISTRIBUTION OF BACTERIOPLANKTON IN T HE KARA SEA IN SEPTEMBER 1993

The bacterial cell number in the water column of the Kara Sea and estu ary areas of the Ob and Yenisei rivers was determined in water samples collected at 32 stations at the depths from the surface to 200 m. The samples were analysed by the direct microscopy. In most parts of the sea the microorganisms concentrations ranged generally from 10(3) to 1 0(4) cells per ml and their biomasses - from milligrams to tens of mil ligrams per 1 m3. The bacterioplankton concentration in river waters w as much higher than in the open sea, especially in the Ob waters. The highest bacteria concentrations - hundreds of thousands cells per ml w ith the biomass exceeding 200 mg per 1 m3 - were found in the southern part of the Ob crossection. The minimum quantities were observed at t he north-eastern part and near the south-eastern coast of Novaya Zemly a. The dark CO2 fixation rates determined at some stations indicated l ow bacteria biomass production.