Bacterial and Archaeal Communities within a High-altitude Soda Lake in the Qinghai-Tibet Plateau, China

Damqiong Co Lake (DCL) is a high-altitude (4,450 m) soda lake with high salinity (122.45 ± 6.20 g/L) and carbonate concentrations ((10 ± 0.21 g/L of CO32- and 8.77 ± 0.07 g/L of HCO3-) in the Qinghai-Tibet Plateau (QTP). High-throughput sequencing of 16S rRNA genes was used to examine bacterial and archaeal community compositions in the DCL. The result showed that bacterial diversity (Shannon index values of 4.18 ± 0.42) in DCL were significantly higher (P = 0.012) than Archaeal (2.27 ± 1.01). Bacterial communities comprised by 25 phyla, 40 classes, and 205 genera. The dominant bacterial phyla were the Firmicutes (11.23%–70.05%), Proteobacteria (15.47%–45.27%), Bacteroidetes (9.87%–27.88%) and Actinobacteria (0.98%–11.55%). The dominant bacterial genera were Gracilimonas (1.25%–18.95%), Halomonas (3.99%–15.02%), Nitriliruptor (0.76%–11.30%), Bradymonas (0.08%–6.66%), and Brumimicrobium (0.04%–6.47%). Archaeal communities comprised by 5 phyla, 4 classes, and 26 genera. The dominant archaeal phyla were Euryarchaeota (3.69%–97.12%) and Woesearchaeota (2.85%–92.26%), while the dominant genera were Methanomassiliicoccus (0.36%–76.88%), Woesearchaeota AR16 (2.18%–48.61%), Methanolobus (0.32%–19.87%), and Woesearchaeota AR15 (0.27%–18.20%). Correlation heatmap indicated that the diversity in DCL was highly correlated with pH, CO32-, Cl-, Na+, Mg2+, and temperature (P < 0.001). The unique dominant genera of Bacteria (Bradymonas) and Archaea (Methanomassiliicoccus) in DCL suggests that valuable microbial resources may exist in high-altitude soda lakes like the DCL.