Respiratory Activity and Biodiversity of Microbiomes in Podzolic Soils of Post-Pyrogenic Spruce Forests in the Krasnoyarsk Krai and Komi Republic

Microbiological properties of podzolic soils (Retisols) of old-aged spruce forests in the middle taiga of the Krasnoyarsk Krai and Komi Republic are described. Despite the geographical distance, the soils of these regions are similar in their morphological and physicochemical characteristics. Any statistically significant difference in the accumulation of microbial biomass and microbial respiration rate in the soils under spruce forests of the European North (Komi Republic) and Central Siberia (Krasnoyarsk Krai) is unobservable. However, the contents of carbon, nitrogen, and microbial biomass in soil have a significant effect on the composition of microbiomes in pyrogenic and nonpyrogenic soil horizons. In addition, the pyrogenic factor considerably influences the alpha-diversity of bacteria and fungi. As is shown, representatives of the dominant phyla of bacteria (Proteobacteria, Actinobacteria, and Planctomycetes) and fungi (Ascomycota, Basidiomycota and Mucoromycota) are actively involved in the assimilation of organic matter containing pyrogenic carbon. The microbiomes of the upper pyrogenic subhorizons include the groups of carbotrophic bacteria (Thermomonosporaceae, Isosphaeraceae, Bacillaceae, and Xanthobacteraceae) and fungi from the Dothideomycetes (Cenococcum), Eurotiomycetes (Penicillium), Sordariomycetes (Trichoderma), Leotiomycetes (Oidiodendron), and Umbelopsidomycetes (Umbelopsis) classes, which are capable of converting pyrolysis products into available and nontoxic substrates for other organisms.