First data on total and carbon cycling microbial diversity of the key reference soils of the “Ladoga” carbon measurement supersite

The “Ladoga” carbon supersite is part of the All-Russian carbon monitoring national system, it is located in the Boreal coniferous forest zone, and work is underway here to implement measures to control the emission of greenhouse gases. This study reports data on the total and carbon-associated diversity of the soil microbes of reference soils. We obtained 729 amplicon sequence variants from 35 soil samples. Total diversity is represented by 11 phyla of bacteria and 1 phylum of methanogenic archaea (for Histosol). Carbon-cycling bacteria diversity is represented by six phyla (Actinobacteriota; Proteobacteria; Acidobacteriota; Bacteroiodota; Firmicutes; and Verrucomicrobiota). The dominant carbon-cycling bacteria in the studied soils are Actinobacteriota and Proteobacteria. The analysis of α- and β-diversity allowed us to identify three clusters of microbiota different in taxonomic composition — these are topsoil of Podzol and subsoil of Podzol (statistically significant (p < 0.05) differences in abundance for Proteobacteria and Verrucomicrobiota were revealed). Histosol is distinguished in a separate cluster of microbial diversity; it differs from Podzol in the abundance of carbon-cycling bacteria by Proteobacteria and Bacteroiodota (p < 0.0001). Further studies of the soil microbiome of the “Ladoga” carbon supersite should be focused on the study of functionally specialized groups of carbon and nitrogen cycle microbes and their ecosystem functions.