TAXONOMIC STRUCTURE OF HYDROCARBON-OXIDIZING BACTERIOCENOSES OF AQUATIC ECOSYSTEMS IN DIFFERENT CLIMATIC ZONES

The structure, physiology, biochemistry and lipid composition of hydro carbon-oxidizing bacterial assemblages have been studied in bacteria i solated on a paraffin-containing liquid medium, paraffin being the sol e source of carbon and energy. Water samples were collected from the A ntarctic and tropical sea waters with varying degree of pollution, and from West Siberian freshwater basins. Rhodococci have been found to c onstitute more than 90% hydrocarbon-oxidizing bacteriocenoses forming in waters with chronic petroleum pollution (at the port of Havana, oil extraction sites in West Siberian marsh land). In waters with a lower pollution level, as well as in sewage polluted waters, the rhodococci abundance was found to decline to 60-80%. Rhodococcus erythropolis wa s the dominant species there, its slimy analog in the Antarctic waters being Rhodococcus aquosus. In nonpolluted waters of the Gulf of Mexic o rhodococci have been absent, hydrocarbon-oxidizing bacteriocenoses f ormation being extremely slow and represented almost entirely by the g enus Pseudomonas. Rhodococci and Pseudomonas are the main representati ves of aquatic hydrocarbon-oxidizing bacteriocenoses, arthrobacteria b eing next in importance. The fatty-acid spectra of the rhodococci grow n in hexadecane medium show a characteristic predominance of normal sa turated acids with an even number of carbon atoms. The noted features are not considered species specific.