The Effect of Organic Carbon on Soil Bacterial Diversity in an Antarctic Lake Region

This study assessed the effects of changes in organic carbon content on soil bacterial community composition and diversity in the Antarctic Fildes Peninsula. 16S rRNA gene sequencing was performed to investigate bacterial community composition. Firstly, we found that organic carbon (OrC) and nutrients showed an increasing trend in the lake area. Secondly, soil geochemistry changes affected microbial composition in the soil. Specifically, we found 3416 operational taxonomical units (OTUs) in 300 genera in five main phyla: Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi, and Bacteroidetes. Although the diversity was similar among the four sites, the composition was different. Among them, Hungateii content changed very significantly, from 16.67% to 33.33%. Canonical correspondence analysis showed that most measured geochemical factors were relevant in structuring microbiomes, and organic carbon concentration showed the highest correlation, followed by NO-N. Hungateii was significantly correlated with the content of organic carbon. Our finding suggested organic carbon played an important role in soil bacterial communities of the Antarctic coastal lake region.