Diversity and activity of sulfate-reducing prokaryotes in a Kamchatka hot springs

Microbial communities of terrestrial hot springs of the Kamchatka Peninsula were studied using amplification and sequencing of 16S rRNA and dsrAB gene fragments. The results showed the presence of various sulfate-reducing prokaryotes in these habitats. It was found that sulfate-reducing prokaryotes belonging to Deltaproteobacteria (Thermodesulforhabdus, Desulfosoma and other members of the Syntrophobacteraceae family), Nitrospiriae (Thermodesulfovibrio), Firmicutes (Desulfotamaculum, Desulfurispora, Desulfmormobacteria) inhabit in neutrophilic and slightly acidic hot springs, while bacteria of the genus Thermodesulofobium prefer moderate acidic hot springs. In high-temperature acidic hot springs, sulfate reduction is mediated by archaea of the Crenarchaeota phylum, the most likely candidates being chemoorganoheterotrophic strains of the genus Vulcanisaeta.