Endolithic Bacterial Communities in Dolomite and Limestone Rocks from the Nanjiang Canyon in Guizhou Karst Area (China)

Phylogenetic diversities of the endolithic bacterial communities in dolomite and limestone rocks from a karst canyon (Nanjiang Canyon), China, were analyzed based on the 16S rRNA gene analysis. In the dolomite endolithic bacterial communities, members of Cyanobacteria were the most abundant followed in abundance by members of Alphaproteobacteria, Acidobacteria, and Actinobacteria. Members of Betaproteobacteria, Deltaproteobacteria, Bacteriodetes, Verrucomicrobia, and Chloroflexi were also present. Large percentages of bacterial clones in the limestone were related to the Actinobacteria, Alphaproteobacteria, and Cyanobacteria. In addition, members of Deltaproteobacteria, Bacteriodetes, Chloroflexi, Acidobacteria, Firmicutes, Planctomycetes, and Candidate division TM7 were identified. Slight differences in endolithic bacterial abundance and community structure existed between the dolomite and limestone rocks. These rock microorganisms are inferred to have played an important role in the formation of Karst soil from carbonate rocks during a long geological history.