Salinity Shapes the Microbial Communities in Surface Sediments of Salt Lakes on the Tibetan Plateau, China

The extreme geographical and climatic conditions of the Tibetan Plateau result in lakes spanning a diverse range of environmental conditions. Studying microbial response to extreme environmental conditions is important for understanding their adaptation and evolution in the natural environment. In this study, the microbial community composition in the surface sediments from 12 lakes with different salinities on the Tibetan Plateau were analyzed using the Illumina high-throughput sequencing platform. The results showed that the phyla Proteobacteria and Bacteroidota were the major bacteria, and Crenarchaeota was the major group of archaea in low and moderately saline lakes (salinity 0.64–33.88PSU), whereas Firmicutes and Halobacterota increased significantly in high saline lakes (salinity 44.25–106.9PSU). Salinity was the most important factor impacting bacterial α-diversity, characterized by a significant decrease in microbial diversity indices with increasing salinity. Salinity was also the main driving factor determining the microbial community composition of these lakes. Other factors, including Chl-a, OM and glacial meltwater, also had important effects to some extent. In contrast, geographic factors had no remarkable effect on microbial community composition.