Distribution and diversity of sulfur-oxidizing bacteria in the surface sediments of Tibetan hot springs

Abstract:

[Objective] To study the distribution and diversity of sulfur-oxidizing bacteria (SOB) in the surface sediments of Tibetan hot springs. [Methods] We collected 25 hot spring sediments from 5 Tibetan geothermal areas. In the field or laboratory, we measured the physicochemical parameters of water or sediment samples. We constructed soxB gene-based clone libraries and performed phylogenetic analysis to analyze the SOB community diversity. We conducted statistical analysis to assess the influencing factors on the SOB community. [Results] Phylogenetic analysis showed that the SOB mainly consisted of α-Proteobacteria, β-Proteobacteria and γ-Proteobacteria in the Tibetan hot spring sediments. The former were dominant classes. The dominant SOB classes differ among the sampled hot springs in our research:β-Proteobacteria were dominant in most of the studied samples, whereas only a few of them were dominated by α-Proteobacteria or γ-Proteobacteria. Mantel test showed that the SOB community composition of the studied samples significantly (P<0.05) correlated with altitude, conductivity, pH, sulfide, total dissolved solids and temperature. [Conclusion] In Tibetan hot spring sediments, α-Proteobacteria and β-Proteobacteria were the main SOB communities, but γ-Proteobacteria was rare. The SOB community structures differed significantly among the studied hot springs, which is mainly caused by their different physical and chemical properties.

Key words:Tibet;hot springs;sulfur-oxidizing bacteria;sulfur cycle;soxB gene