Diversity and Functional Potential of Prokaryotic Communities in Depth Profile of Boreo-Nemoral Minerotrophic Pine Swamp (European Russia)

Abstract

Natural peatlands represent a wide range of habitats that contribute to the conservation of biodiversity, including microbial biodiversity. Molecular biological methods make it possible to significantly increase the accounting of microbial diversity compared to the cultivation methods. The studies on microbial diversity in minerotrophic peatlands using molecular biological methods lag significantly behind such studies for ombrotrophic peatlands. In this work, we characterized the taxonomic composition and functional potential of the prokaryotic community of the minerotrophic pine swamp (fen) in the Tver region of northwestern Russia using high-throughput sequencing of 16S rRNA gene fragments. This study is unique, since it was carried out not in individual horizons but across the entire fen profile, taking into account the differentiation of the profile into the acrotelm and catotelm. The composition and dominants of bacterial and archaeal communities were determined not only at the level of phyla but also at the level of classes, families, and cultivated genera. The prokaryotic community of the studied fen was shown to have a high taxonomic diversity (28 bacterial and 10 archaeal phyla were identified). The profile differentiation of the taxonomic composition of prokaryotic communities is most clearly manifested in the analysis of the acrotelm and catotelm. In the bacterial communities of the acrotelm, the top three phyla included Acidobacteriota, Alphaproteobacteria, and Actinomycetota, in the catotelm—Betaproteobacteria, Bacteroidota, and Chloroflexota. In archaeal communities of the acrotelm, we discovered the monodominance of Nitrososphaerota, in the catotelm—the dominance of Bathyarchaeota and subdominance of Thermoplasmatota, Halobacterota, and Aenigmarchaeota. The hot spots of microbial diversity in the studied fen profile were found to be the 0–20 cm layer of the acrotelm and the 150–200 cm layer of the catotelm. In contrast to the taxonomic composition, the functional profiles of the prokaryotic communities of the acrotelm and catotelm were generally similar, except for methane metabolism, which was primarily carried out in the catotelm.