Bacterial Diversity And Geographical Distribution Of The East China Sea Coast

Marine bacteria play a major role in the synthesis and decomposition of organic compounds, the restoration of the marine environment and the processes of energy and nutrients cycle such as carbon, nitrogen, sulfur in marine ecosystems. In addition, Marine bacteria is the core of the marine micro food cycle to maintain the diversity of the marine ecosystem. In this study, We collected sediment and surface sea water samples in the East China Sea in April and May 2007 and June 2013, respectively. Five sediment samples were distributed from the Hangzhou Bay to the edge of Okinawa trough in East China Sea. And,Seven surface sea water samples are mainly from the coastal of Shanghai and Zhejiang.We constructed 16 S rDNA clone library in five sites in the East China Sea. The results showed that there were 508 bacteria sequences containing 319 OTUs and the bacteria sequences belonged to 13 groups, including Proteobacteria, Firmicutes, Acidobacteria,Chloroflexi, Actinobacteria, Nitrospira, WS3, Bacteroidetes, Spirochaetes, OP8,Planctomycetacia, Verrucomicrobia and Gemmatimonadetes. The Proteobacteria and Chloroflexi were the dominant groups of all sites. The bacterial content was above 50% and major dominant group in DH6, DH16, DH17 and DH21 site. Chloroflexi was the most abundant and the content was 26% in DH9. In the Proteobacteria, the bacterium from Delta-proteobacteria had significant advantages in DH6 and DH16; the bacterium from Delta-proteobacteria were dominant groups in DH17 and DH21. WS3, Verrucomicrobia,and Gemmatimonadetes were unique to Sites DH6, DH9 and DH21, respectively.According to the diversity and richness index showed that the descendent order of bacterial diversity was DH16< DH6< DH17< DH21< DH9. In end, the phylogenetic tree and classification of homologous sequences indicated significantly species diversity and genetic diversity of bacteria in the East China Sea layer sediments.The research collected 7 sites' samples from the surface seawaters of the East China Sea coast, and analyzed the community structures of bacterioplankton by 16 S rDNA clone library, then estimated the relationships of community structures with environmental factors. The clone library results showed that bacterioplankton community from the ZJ0902 site had the highest richness and diversity in the East China Sea. These bacterioplankton belonged to 10 groups, including Proteobacteria, Firmicutes, Actinobacteria,Cyanobacteria, Candidate division TM6, Bacteroidetes, Fibrobacteres, Microgenomates(OP11), Verrucomicrobia, Gemmatimonadetes. Proteobacteria was the main dominant group, the content of Actinobacteria(42.9%) was the highest in SH3101; Cyanobacteria(60%) was absolutely dominant groups in SH3102; Firmicutes(65.8%) was absolutely dominant groups in ZJ0205, and Proteobacteria was the main dominant group in other sites.Microgenomates, Verrucomicrobia, Gemmatimonadetes were unique groups in the ZJ0902 site. Bacterioplankton communities from 7 sites samples were divided into four categories by CLUSTER and MDS basing on composition similarity. However, envfit() function analysis showed that there was no correlation between environmental factors and bacterial community. Finally, RDA results indicated that salinity had positive correlation with Alpha-proteobacteria and negative influence on the Beta-proteobacteria; Inorganic nitrogen negatively affected Alpha-proteobacteria; Active phosphate was positively relative with Actinobacteria.