Biomass and respiration activity of soil microorganisms in anthropogenically transformed ecosystems (Moscow region)

In the forest, meadow, arable, and urban ecosystems (recreational, residential, and industrial zones) of Sergiev Posad, Shatura, Serpukhov, and Serebryanye Prudy districts of Moscow region, spatially separated sites (3–5 points per site) have been randomly selected and soil samples have been taken from the 0–10 (plant litter excluded) and 10- to 150-cm layers (a total of 201 samples have been taken). In the samples, the microbial biomass carbon (Cmic), the rate of the basal (microbial) respiration (BR), and the physical parameters (the particle size distribution (PSD), organic carbon (Corg), pH, heavy metals, and nutrients (NPK)) have been determined. High spatial variability has been revealed for Cmic and BR in all the ecosystems and the functional zones of the studied districts, and a clear tendency of a decrease in these parameters has been shown in the arable soils (by 1.4–3.2 times) and the industrial zone (by 1.7–3.3 times) compared to the natural analogues and other corresponding functional zones. It has been shown that the spatial distribution of the microbiological parameters is significantly (p ≤ 0.05) affected by the physicochemical properties of the soil (Cmic by the PSD and PSD × Corg; BR by the pH and pH × NPK; contributions of 40 and 63%, respectively), as well as by the type of ecosystem and the region of study (the contribution of the sum of these factors to the Cmic and BR was 56 and 67%, respectively). A tendency toward the deterioration of the functioning of the microbial community under the anthropogenic transformation of the soil has been shown. The contribution of the urban soils as a potential source of CO2 emission to the atmosphere has been calculated and discussed.