An evaluation of the core bacterial communities associated with hypersaline environments in the Qaidam Basin, China

Abstract

Hypersaline lakes and saltern areas are important industrial and biodiversity resources in the Qaidam Basin of China that reside at > 2600 m asl. Most hypersaline environments in this area are characterized by saturated salinity (~ 300 g/L salinity), nearly neutral pH, intense ultraviolet radiation, and extremely variable temperature fluctuations. The core bacterial communities associated with these stressful environments have nevertheless remained uninvestigated. 16S rRNA gene Illumina sequencing analyses revealed that the bacterial communities were dominated by core lineages including the Proteobacteria (39.4-64.6%) and the Firmicutes (17.0-42.7%). However, the relative abundances of common lineages, and especially the five most abundant taxa of Pseudomonas, Lactococcus, Anoxybacillus, Acinetobacter, and Brevundimonas, were highly variable across communities and closely associated with hypersaline characteristics in the samples. Network analysis revealed the presence of co-occurrence high relative abundance taxa (cluster I) that were highly correlated across all hypersaline samples. Additionally, temperature, total organic carbon, K⁺, and Mg²⁺ correlated highest with taxonomic distributions across communities. These results highlight the potential mechanisms that could underlie survival and adaptation to these extreme hypersaline ecosystems.

Keywords: Bacterial community; Bacterial diversity; Co-network; Common lineages; Hypersaline environments; Qaidam Basin.