Microbial community structure in hypolentic zones of a brine lake in a desert plateau, China

Microbes participate in a series of complex biogeochemical processes including nitrogen and sulfur circulation. Microbial species active in the nitrogen and sulfur cycles can be used for nitrogen and sulfur pollution remediation, preserving and keeping the ecosystem in balance. Hypolentic zones in brine lakes contain stable, elevated pH and total dissolved solids and provide a unique habitat for a rich diversity of haloalkaliphilic bacteria and archaea. Few studies have investigated the diversity and microbial community structure in the sedimentary environment of hypolentic zones in brine lakebeds located on desert plateaus. In this study, sedimentary environmental characteristics, species abundance and diversity were investigated, as well as the relationships between them. Analyses revealed important roles of different bacterial species in the microbially mediated nitrogen and sulfur biogeochemical cycles in the brine lakebed. Further, the study revealed details of the ecosystem dynamics of these extreme environments, under the action of microorganisms. The biogeochemical dynamic response of different hydraulic and hydrochemical characteristics was illuminated. It showed that the amount of deoxyribonucleic acid in the sediment was interrelated with the components of brine water and depth of the hypolentic zone and was higher in brine and reduction conditions, with the stronger hydraulic forces. In the hypolentic zone of the brine lake, microbial species composition was remarkably correlated with environmental factors, spatial environmental factors and hydrogeological conditions, such as hydraulic and hydrochemical characteristics.