Spatial and Temporal Variation of Bacterial Community Structures and Their Main Environmental Influencing Factors in Sediment Environment of Xihu Area in Xiangshan Bay

In order to reveal the health status of the eco-environment of Xihu area in Xiangshan Bay, the sediment and water samples were collected in August 2009, March, May and August in 2010, May and August in 2011. The bacterial community structures and predominant bacterial species were investigated using PCR-Denaturing Gradient Gel Electrophoresis(DGGE),and the correlation between the bacterial community and the main environmental influencing factors were analyzed by using redundancy analysis(RDA). The results of PCR-DGGE showed the dominant bacterial phyla in sediment environment in Xihu area were Proteobacteria, Firmicutes, Bacteroides, Chloroflexi and Acidobacteria. In the bottom part, the dominant bacteria was not obvious in August 2009, but Lactobacillales, Pseudomonadales, Alteromonadales, Chloroflexi and Burkholderiales appeared as alternate dominant groups during the following 5 periods with time going on. For the middle-east part,Lactobacillales, Pseudomonadales, Pseudomonadales, Vibrionales, Pseudomonadales, Lactobacillales were observed as alternate dominant bacteria during the 6 periods. The result of RDA analysis showed that the main environmental influencing factors on the bacterial community structures in the sediment of the bottom part were active silicate, dissolved inorganic nitrogen and chemical oxygen demand, but active silicate, dissolved inorganic nitrogen and ammonia for the sediment of the middle-east part, indicating that the variation of bacterial community structures are the results of the synergistic effects of several environmental factors.