Bacterial and Archaeal Communities Within the Alkaline Na2CO3-type Langaco Lake in the Qinghai-Tibet Plateau

Langaco Lake (LGL) is a strong Na2CO3-type lake that sits at an altitude of 4,548 m in the Qinghai-Tibet Plateau of China. LGL exhibits unique hydrochemical characteristics among Na2CO3-type lakes, but little is known about the microbial diversity of LGL and their interactions with environmental factors. Here, high-throughput sequencing of 16S rRNA genes revealed that LGL bacterial diversity comprised 327 genera in 24 phyla (4,871 operational taxonomic units [OTUs]; Shannon index values of 5.20–6.07) that represented significantly higher diversity than that of Archaea (eight phyla and 29 genera comprising 1,008 OTUs; Shannon index values of 2.98–3.30). The bacterial communities were dominated by Proteobacteria (42.79–53.70% relative abundances), followed by Bacteroidetes (11.13–15.18%), Planctomycetes (4.20–12.82%), Acidobacteria (5.91–9.50%), Actinobacteria (2.60–5.80%), and Verrucomicrobia (2.11–4.08%). Further, archaeal communities were dominated by Crenarchaeota (35.97–58.29%), Euryarchaeota (33.02–39.89%), and Woesearchaeota (6.50–21.57%). The dominant bacterial genus was Thiobacillus (8.92–16.78%), whose abundances were most correlated with total phosphorus (TP), pH, CO32− concentrations, and temperature. The most abundant archaeal genus was Methanoregula (21.40–28.29%), whose abundances were most highly correlated with TOC and TS in addition to the concentrations of K+, and Na+. Taken together, these results provide valuable insights towards a more comprehensive understanding of microbial diversity in these unique carbonate alkaline environments, in addition to a better understanding of microbial resources in the Qinghai-Tibet Plateau.