Bacterial community structure in lakes on the northeastern Qinghai-Tibetan Plateau

The northeast of Qinghai-Tibetan Plateau is located in the convergence zone of the monsoon region of eastern China, northwest arid area and Qinghai-Tibetan Plateau region. During April to May 2012, an investigation was carried out on the bacterial community structure in ten lakes on northeastern Qinghai-Tibetan Plateau. With 16S rRNA sequencing and PCR-DGGE technology, twelve bacteria genus level libraries were constructed with a total of 117 operational taxonomic unit including 27 Betaproteobacteria, 8 Gamaproteobacteria, 21 Alphaproteobacteria, 7 Deltaproteobacteria,16 Acidobacteria, 2 Deinococci, 5 Sphingobacteria, 6 Flavobacteria, 5 Nitrospira, 11 Actinobacteria, 6 Gemmatimonadetes and 3 unclassified bacteria. Most sequences in these studied lakes were closer to aquatic bacteria than any other bacterial clusters. The number of operational taxonomic unit in northeastern Qinghai-Tibetan Plateau was 32.1 ± 11.2, Shannon-Wiener diversity index 0.97 ± 0.29, Pielou's evenness index 0.19 ± 0.04, and Sorenson similarity index between lakes 0.31 ± 0.11, all comparatively low. Notably, the environment factors played an important role in bacteria community, with temperature positively related to OTUs (R = 0.763, P < 0.05), to Shannon-Wiener diversity index (R = 0.708, P < 0.05), and to Pielou's evenness index (R = 0.641, P < 0.05); the lake area was also positively related to OTUs (R= 0.754, P < 0.05) and Shannon-Wiener diversity index (R = 0.668, P < 0.05). Water chemistry also played an important part in bacteria community. The result is helpful for study of climatic factors of community structure and sustainable development in this region.