Bacterial diversity in the polluted water of the Dianchi Lakeshore in China

Dianchi Lake is a typical Chinese eutrophic lake. The bacterial community in the polluted water of the Dianchi lakeshore was investigated by cultivation-independent approaches. The amplicon length heterogeneity polymerase-chain reaction (LH-PCR) was used to detect the major differences in bacterial structure among the nine different sampling sites. Cluster analysis shows that the bacterial communities in water blooming sites were similar. Three genes were employed to characterize bacteria in the two parts of Dianchi Lake. The 16S rRNA gene was used to analyze the total bacterial community, the ammonia monooxygenase (amoA) gene for detecting ammonia-oxidizing bacteria, and the nitrous oxide reductase (nosZ) gene for identifying denitrifying bacteria. The clone library results demonstrate that Proteobacteria, Bacteroidetes, and Cyanobacteria were the dominant bacteria in both parts of the lake. The communities of ammonia-oxidizing bacteria were very different in the two parts of the lake and belonged to Nitrospira in the north and Nitrosomonas in the south part, respectively. Denitrifying bacteria in the Dianchi lakeshore were related to several cultured denitrifiers such as Pseudomonas, Paracoccus, Achromobacter, and Rubrivivax.