Functional Groups of Bacteria and Their Involvement in Geochemical Processes in Microbial Communities of Mineral Sources in Sakhalin Island (Far East, Russia)

Abstract

The chemical composition of mineral waters as well as the diversity, quantity and distribution peculiarities of different functional groups of bacteria in microbial mats in Sakhalin mineral springs was studied. The prevalence of sodium cations in the composition of bicarbonate anions and chloride ions was noticed. The studied waters were substantially enriched with silicone, iodine, boron, iron and strontium. It was established that the main morphogenic bacteria in the mats of cold springs were the colorless sulfur bacteria Thiotrix sp. The microbial mats formed at the outlets of Sakhalin mineral springs contain a high quantity of different functional bacteria groups that play an important role in the geochemical cycles of carbon, nitrogen, sulfur, iron and manganese. Prevalence of bacteria of sulfur and carbon cycles is a peculiarity of microbial mats in Antonovsky and Nevelsky mineral waters. The important role of sulfur cycle bacteria is confirmed by high quantities of thionic, sulfate-reducing bacteria and colorless sulfur bacteria. The mat of Alexandrovsky thermal spring contains a high amount of bacteria of carbon and nitrogen geochemical cycles; an important role of these microorganisms in mat’s functioning is shown. Pure bacterial cultures were isolated; they mostly include gram-positive, spore-forming motile rods Bacillus sp.