TRANSFORMATION OF ORGANIC-COMPOUNDS IN THE SEDIMENTS OF A EUTROPHIC LAKE

The decomposition of glucose, lactate, and butyrate was studied by the radioisotopic method in littoral sediments of a eutrophic lake over t he period of spring water circulation. Fatty acids (C-2-C-4), CO2, and methane were revealed among the decomposition products. All the proce sses studied showed periodical oscillations with a frequency from two to several weeks and an amplitude of an order of magnitude or more. Th is periodicity was not directly related to variations in the environme nt, but was likely a result of the regulation of organic carbon flows in the microbial community, which was realized through changes in the rates of the production and consumption of different exometabolites. A direct correlation was revealed between acetate production from lacta te and the content of acetate in the silt water. The rates of glucose, lactate, and butyrate mineralization increased throughout the entire investigation period.