Bacterial Community And Environmental Influencing Factors In Rehabilitative Sediment Environment Of Xiangshan Bay

In order to investigate the dynamics of the bacterial communities in the cultureareas in the middle part of Xiangshan Bay, to reveal the health condition of the marineecological environment from the angle of microbiology and promote the stable andsustainable development of the region, PCR-DGGE and redundancy analysis (RDA)are used to study the variations of the bacterial community structure and the maininfluencing environmental factors in this paper. The main results are as following.1. The results of PCR-DGGE show that mainly7kinds of dominant bacterialphyla, Proteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, Actinobacteria,Acidobacteria, Verrucomicrobia, are found in the sediment environment in NanshaBay. In the cage culture area, the dominant bacteria are Moraxellaceae,Phyllobacteriaceae and Chloroflexi in August2009and March2010, Moraxellaceae,Phyllobacteriaceae, Pseudomonadaceae and Chloroflexi in May2010,Desulfobacteraceae, Enterobacteriaceae and Desulfobulbaceae in August2010,Moraxellaceae, Phyllobacteriaceae and Chloroflexi in May2011, Actinobacteria,Alteromonadaceae and Brucellaceae in August2011.While in the macro-algae culturearea, the domain bacteria and the structure keeps relatively stable and the dominantbacteria are Chloroflexi, Moraxellaceae, δ-Proteobacteria, Alteromonadaceae,Vibrionaceae, Burkholderiaceae, Rhodobacteraceae and Phyllobacteriaceae. RDAanalysis shows that ammonium-nitrogen and COD are the main factors influencingthe variation of bacterial diversity, the improving trend in bacterial communities iscoralated with that of chemical environment. The result demonstrates that usingmacroalgae to restore the habitat of cage culture area is effective, suggesting thatbacterial community structure can be used as one of the indexes to evaluate the habitatrestoration effect. 2. The results of PCR-DGGE show that mainly5kinds of dominant bacterialphyla, Proteobacteria, Firmicutes, Bacteroides, Chloroflexi and Acidobacteria, arefound in sediment environment in Xihu area. In the bottom part, the dominant bacteriais not obvious in August2009,but Rhodospirillaceae, Moraxellaceae,Alteromonadaceae, Chloroflexi and Burkholderiaceae appears as dominant groups inturn during the following5periods with time going on. While in the middle-east part,Lactobacillaceae, Pseudomonadaceae, Pseudomonadaceae, Vibrionaceae,Pseudomonadaceae and Lactobacillaceae are observed as dominant bacteria in turnduring the6periods. The result of RDA analysis shows that, the main environmentalinfluencing factors to the bacterial diversity in the sediment of the bottom part areactive silicate, dissolved inorganic nitrogen and chemical oxygen demand, while theyare active silicate, dissolved inorganic nitrogen and ammonia for the sediment of themiddle-east part, which indicated that the variation of bacterial community structuresare the results of the synergistic effects of several environmental factors.3. In Shiyan bay, The PCR-DGGE analysis indicates that4phyla lineage of thedomain bacteria are mainly composed in the macro-algae culture area. The dominantbacteria are Moraxellaceae in August2009and March2010, Aeromonadaceae andMycobacteriaceae in August2010and May2011, Bacillaceae in August2011. RDAanalysis shows that NH4-N, SiO4-Si and N/P are the main factors influencing thevariation in bacterial diversity.