A Comparison of the Bacterial Diversity of Two Shallow Freshwater Lakes in China

Abstract

The objective of the present study was to determine the bacterial diversity present in the water samples taken from two shallow freshwater lakes in China. The water samples were collected from the Lake Nanhu, a hyper-eutrophic lake, and Lake Niushan, a mesotrophic lake. To determine the bacterial diversity, a 16S ribosomal RNA gene clone library from each lake, using the bacterial PCR primers 27F and 1492R, was prepared. A total of 119 near-full-length sequences were analyzed and 44 Operational Taxonomic Units (OTUs) were identified for Lake Nanhu. Seven different phyla were identified in which 42 OTUs were classified. Most of the OTUs contained sequences belonging to the phylum Proteobacteria (40.9 %), followed by Actinobacteria (15.9 %), Cyanobacteria (11.4 %), Verrucomicrobia (11.4 %), Plantomycetes (6.8 %), Bacteroidetes (4.5 %) and Chloroflexi (4.5 %). A phylum could not be assigned for clones within 2 OTUs (4.5 %). A total of 90 partial sequences were analyzed and 50 OTUs were identified for Lake Niushan. Most of the OTUs contained sequences belonging to the phyla Proteobacteria (40.0 %), followed by Bacteroidetes (16.0 %), Cyanobacteria (12.0 %), Plantomycetes (8.0 %), Verrucomicrobia, (6.0 %), Actinobacteria (4.0 %), Firmicutes (4.0 %) and Candidate Division OP10 (2.0 %). A phylum could not be assigned for clones within 4 OTUs (8.0 %).