Bacterioplankton in the lower Amur River

The main microbiological characteristics of the waters of the lower Amur River are presented: the total abundance of bacterioplankton (TAB) and its biomass, the number of aquatic fungi and bacteria belonging to certain physiological groups, the intensities of CO2 dark assimilation (DA), methane oxidation (MO), and organic matter decomposition (D), and also the rates of growth and production of bacterioplankton. Spatial and seasonal heterogeneity of bacterioplankton is shown. River water zones subjected to a heavy anthropogenic load were revealed, where the number and physiological activity of bacteria increased 10-10(3)-fold. TAB increased to 7-8 x 10(6) cells/ml with the numbers of saprophytic and cellulolytic bacteria amounting to 5-6 x 10(3) and 2 x 10(3) cells/ml, respectively, and coli-index increasing to 2500. The daily intensities of the processes also increased: DA-up to 15 mu g C/l, MO-up to 5 mu l CH4/l, and D-up to 0.5 mg C/l.