Comparison of Prokaryotic Communities Associated with Different TOC Concentrations in Dianchi Lake

Abstract

The effect of total organic carbon (TOC) on the prokaryotic community structure in situ has been rarely known. This study aimed to determine the effect of TOC level on the composition and networks of archaeal and bacterial communities in the sediments of Dianchi Lake, one of the most eutrophic lakes in China. Microbial assemblages showed significantly associations with TOC. Moreover, relatively high and low TOC formed taxonomic differences in prokaryotic assemblages. According to the results, the most abundant bacteria across all samples were identified as members of the phyla Proteobacteria, Nitrospirae, Chloroflexi, Firmicutes and Ignavibacteriae. The dominant groups of archaea consisted of Euryarchaeota, Woesearchaeota DHVEG-6, Bathyarchaeota and WSA2. Lastly, the meta-analysis results highlighted that the low TOC (LT) prokaryotic community structure is larger and more complex compared to moderate TOC (MT). On the whole, the prokaryotic community structure is obviously distinct among groups with different TOC levels, and LT communities may interact with each other strongly in the Dianchi Lake sediment. This study can provide more insights into prokaryotic assemblages in eutrophic lake sediment and provide suggestions for the restoration and maintenance of sediment ecosystems.