Diversity of Microbial Communities of the Shargalzhuut Thermal Spring, Mongolia

This is the first report on characterization of the microbial community of the weakly mineralized alkaline hydrotherm Shargalzhuut by the 16S rRNA gene high-throughput sequencing. Release of the thermal waters is associated with a large tectonic fault in a granitoid massif (Central Mongolia). Comparative analysis of the composition of the dominant taxa was carried out for high-temperature sediments (80–90°C) and microbial mats (45–57°C). High shares of unclassified bacteria and archaea were observed at the class, family, and genus levels. The most numerous class in the Shargalzhuut hydrotherm (Gammaproteobacteria) was represented by unclassified Comamonadaceae and Burkholderiales; members of these taxa are considered the key species of communities of deep fissure fluids. The phototrophic mats consisted mainly of unclassified_Roseiflexus and Candidatus Gloeomargarita.