[Microflora of underground waters in oil and gas fields of Mangyshlak]

The distribution of various physiological bacterial groups with respect to the geological profile and area was studied in underground waters of the gas and oil bearing complexes of Mangyshlak. Metamorphism of the environment in the complexes, in the direction of flow of underground waters, from the oxidative to the reductive medium, is correlated with changes in the composition of the prevailing and accompanying bacterial groups for each of the zones.