The Effects of Salinity and pH on Microbial Community Diversity and Distribution Pattern in the Brines of Soda Lakes in Badain Jaran Desert, China

Abstract

The Badain Jaran Desert (BJD) is characterized by extremely arid conditions. Counterintuitively, this arid region has over 100 permanent lakes. To date, only a few studies have characterized microbial community in these lakes. Our investigation sampled five lakes with salinity (2.1–397.33 g/L) and pH (9.69–10.83) gradients, of which one was low salinity (< 3.0 g/L), three were moderately saline (50–250 g/L) and the other one was hypersaline (>250.0 g/L). Using high-throughput sequencing of 16S rRNA genes, we noted a significant difference in microbial communities inhabiting the different alkali-saline lakes. Generally, bacteria were predominant in the low and moderately saline lakes, while archaea were dominant in the hypersaline lake. The low salinity lake exhibited the highest microbial diversity, dominated by Burkholderia and Halomonas. Spiribacter and Halomonas dominated the moderately saline lakes, while Halohasta and Halosimplex dominated the hypersaline lake. pH was a primary driver of microbial richness, whereas salinity was the predominant factor controlling microbial community composition. Therefore, both pH and salinity shaped the haloalkaliphilic community in the soda lakes. Furthermore, it was found that many haloalkaliphiles such as Spiribacter and Halomonas survived beyond their pH and salinity limits, suggesting that there could be more new species in these soda lakes.