THE EFFECT OF PETROLEUM-HYDROCARBONS ON THE HYDROCARBON-OXIDIZING BACTERIOCENOSIS IN THE SOUTHEAST PART OF THE MOZHAISKOE WATER STORAGE BASIN

Development of the natural hydrocarbon-oxidizing bacteriocenosis and a lterations in its composition caused by the influence of petroleum and diesel fuel were studied in the Mozhaiskoe water storage basin during the summer period. The number of hydrocarbon-oxidizing bacteria was s hown to vary between 25 and 250 cells/ml in the coastal area of the ba sin. The hydrocarbon-oxidizing community included bacteria of the gene ra Acinetobacter, Pseudomonas, Rhodococcus, and Micrococcus; the propo rtion of individual representatives of these genera varied at differen t periods in different parts of the reservoir. Model experiments revea led that the introduction of petroleum hydrocarbons into the reservoir water induced a rapid increase (by two or three orders of magnitude) in the total number of hydrocarbon-oxidizing microorganisms and altera tion of their taxonomic composition, even with a change of dominating genera. Bacteria of the genus Rhodococcus were found to be the most re sistant to the pollutants used.