Spatiotemporal Dynamics of the State of Microbial Communities in Soils of the Steppes of the Volga–Don Interfluve

Abstract

Soil microorganisms are an integral part of the soil. Almost all of the processes taking place in it are associated to some degree with the vital activity of microorganisms. Therefore, the characteristics of the microbial community are among the most important diagnostic indicators reflecting the conditions of soil formation. Paleosols retain a number of properties from the moment of burial, and this is reflected in the corresponding parameters of their microbial community: the active biomass of microorganisms, the ecological–trophic structure of the microbial community, the oligotrophy index, etc. Microbial communities of soils of different ages of different natural regions of the Volga–Don interfluve were studied in order to elucidate the laws of their spatiotemporal change in connection with the existing conditions of soil formation. It is established that the characteristics of the microbial communities of modern soils in the dry and desert–steppe zones of the southeastern Russian Plain to a greater extent reflect the specifics of local conditions of soil formation. Thus, with one subtype of affiliation, soils located in different lithological, geomorphological, and landscape conditions can very noticeably differ in microbiological parameters. Conversely, the characteristics of microbial communities of various soil types (subtypes) can be quite close if the latter are confined to similar relief elements, parent rocks, and levels of groundwater occurrence. The state of microbial communities in a given historical period is largely determined by the laws of evolution of a specific soil area (landscape) and the secular variability of bioclimatic conditions. In this regard, local specificity arises in the dynamics of the state of microbial communities and their structural and functional organization.