Within-lake heterogeneity of environmental factors structuring bacterial community composition in Lake Dongting, China.

Within-lake heterogeneity of bacterial community composition (BCC) was investigated in the large and shallow regulating Lake Dongting. Samples were collected at 13 sites located in different areas of the lake. PCR-denaturing gradient gel electrophoresis (DGGE) and redundancy analysis (RDA) were used for revealing spatial distribution of BCC and the relationships between BCC and environmental variables. The DGGE banding patterns revealed a remarkable spatial heterogeneity which was closely related to their geographical positions. RDA result demonstrated that TP and TN, as well as Secchi depth, were the three most influential factors, responsible for a major part of the observed variation in BCC. Total bacterial abundances were significantly higher in Eastern Dongting due to high TP and suspended solids. In conclusion, bacterial community diversity in Lake Dongting was mainly shaped by within-lake heterogeneity of nutrient and transparency.