Dynamics of Microbiological Water Quality Indicators in the North Caspian Sea

Abstract

Microbial researches of water sampled in summer period of 2015-2017 years in the North Caspian Sea around prospecting wells were held. Sampling realized according to conventional methods in area of five oil fields. There are Rakushechnaya, Sarmatskaya, West-Sarmatskaya, and, Khvalynskaya areas. Relative abundance of saprotrophic microorganisms and total number of bacteria found in water samples were studied. There are three indexes were used for quantity evaluation: Razumov index, water purity level and saprobity index. Study had shown non-uniformly distribution of different groups of microorganisms and their concentrations in the water samples from fields. At the same time the water monitoring had shown the existence of very purify (xeno - and oligosaprobic) and dirty (poly - and hypersaprobic) zones in the Northern Caspian Sea. However, the population dynamics of the saprotrofic microorganisms and the total number of bacteria in summer period of 2015-2016 years around oil fields indicate about successful processes of self-purification of waters and recover of ecosystem after human impact.