Features of the structure and spatial distribution of microbial communities of river ecosystems of the Amur Basin (Eastern Transbaikalia)

Abstract

The spatial distribution and structure of microbial communities of river ecosystems in the Amur basin of Eastern Transbaikalia have been studied. The Argun River and its 7 main tributaries have been studied. It was established that the microbial communities of the upper reaches of the rivers under study are formed under the influence of the temperature factor, and are characterized by the total number of bacteria, which in water averages 1.83 × 106 cells/ml, in soil – 2.21 × 109 cells/ml. In the middle reaches of rivers, a stable rheophilic microbial community is formed, the structure and spatial distribution of which depends on the specific hydrological regime of the river and the landscape of the territory. The total number of bacteria in river water here reaches on average 3.03 × 106 cells/ml, in the soil – 2.52 × 109 cells/ml. In the lower reaches, a microbial community with the characteristics of limnosystems is formed, which has a close relationship with water mineralization and is characterized by an average total number of bacteria in water - 3.12 × 106 cells/ml, in soil - 3.06 × 109 cells/ml. Microbiological assessment of water quality showed that the studied rivers belong to pollution classes I - III, and their waters are characterized as oligosaprobic - transitional from β- to α-mesosaprobic.