| In order to study the diversity of microbial community structure in Songhua Lake，PCR-DGGE（Polymerase chain reaction-denaturing gradient gel electrophoresis） technology is employed to study the bacterial community structure in the different spatial distribution. Each strip as a operational taxonomic unit（OUT）, suggested that bacterial microbial communities with water depth change will have a significant difference, microbial community unit（OUT） numbers higher than other sites in S1 and S2. The Unweighted pair group method with arithmetic averages（UPGMA） dendrogram of sample basis on DGGE fingerprints showed water microbial community diversity presents significant spatial difference, there have similar and dynamic in the different depths of water. Canonical correspondence analysis（CCA） was applied to further investigate the relationships between OTU composition and the environmental factors. The first two CCA ordination axes suggested that the bacterial community composition was primarily correlated with the variables of depth of water（SH）, temperature（Wt），and dissolved oxygen（DO）. The change of depth of water（SH） and temperature（Wt） were the main reason for the change of microbial community structure. |
