Variability of Microbial Biomass in Paleosols of Different-Age Burial Mounds of the Lower Volga Region in Relation to the Dynamics of Climate Humidity

The microbial biomass variability in buried chestnut and light chestnut soils of different ages under burial mounds and their modern background analogs in the Volga and Ergeni uplands were studied. It was shown that almost all microorganisms in chestnut paleosols of the Bronze Age are in the dormant state and provide no respiratory response to the addition of glucose. In the paleosol buried in the most arid period, an increase in the total microbial biomass and the abundance of colony-forming units was revealed. The maxi-mum values of active microbial biomass upon the minimum number of cells were found in soils buried in rel-atively humid periods. The increase in the total microbial biomass and the proportion of microbial cell carbon in the organic carbon of soils buried in extremely dry seasons at the turn of the III–II millennium BC may indicate the adaptation of microbial communities to unfavorable environmental conditions. © 2016, Pleiades Publishing, Ltd.