Abundance and biomass of bacterioplankton in waters of the Kara Sea and the Ob and Yenisey Rivers

Bacterial cell number in the water column of the Kara Sea and estuary areas of the Ob and Yenisey Rivers was determined in water samples collected at 32 stations at depths from the surface to 200 m. The samples were analyzed by direct microscopy. In most parts of the sea microorganism concentrations ranged generally from 103 to 104 cells per ml and their biomasses from milligrams to tens of mg/m**3. Bacterioplankton concentration of river waters was much higher than in the open sea, especially in Ob waters. The highest bacteria concentrations, hundreds of thousands cells per ml with biomass exceeding 200 mg/m**3, were found in the southern part of the Ob section. Minimal concentrations were observed in the northeastern part and near the southeastern part of the Ob section and the southeastern coast of Novaya Zemlya. Dark CO2 fixation rates determined at some stations indicated low bacteria biomass production.

本数据集针对喀拉海以及鄂毕河、叶尼塞河河口区域的水柱生境，于32个站位采集了从表层至200米深度的水样，并测定其中的细菌细胞数量。样品采用直接显微镜计数法（direct microscopy）进行分析。该海域大部分区域的微生物浓度通常介于10³至10⁴个/毫升，对应生物量范围为每立方米数毫克至数十毫克。河水中的浮游细菌（bacterioplankton）浓度远高于外海，尤以鄂毕河水体为甚。鄂毕河断面南部区域检出最高细菌浓度，可达数十万细胞/毫升，生物量超过200毫克/立方米；最低浓度则出现在鄂毕河断面的东北部、东南部近岸区域，以及新地岛的东南海岸附近。部分站位测定的暗二氧化碳固定速率（dark CO2 fixation rates）结果显示，该区域细菌生物量生产水平较低。