Pylogenetic Analysis Of Bacterioplankton And Bacteria In Surface Sediments From The Northern Bering Sea

Biodiversity of bacteria in the bottom and surface water,as well as the bacteria in the top layer of sediments from the Northern Bering Sea,were studied by a combination of PCR-DGGE,RFLP and 16S rDNA analysis.Shannon-wiener's Index and software BandScan were used to evaluate the bacterial biodiversity.The main results were as follows:1.DGGE analysis showed that the bacterial biodiversity of bottom and surface water in the Northern Bering Sea was quite abundant.The Shannon-wiener's Index value and richness of bacteria in the bottom water were higher than those in the surface water.36 sequences fell into six bacterial groups,including gamma-proteobacteria(25.00%),alpha-proteobacterium(22.22%),Actinobacteria (16.67%),Cyanobacteria(11.11%),delta-proteobacteria(5.56%),beta-proteobacteria (2.78%),Firmicutes(5.56%),Bacteroidetes(2.78%) and Verrucomicrobia(2.78%),unidentified bacteria(5.56%).About 83.3%of the sequences had a high similarity with uncultured bacteria,suggesting that there are rich microbial resources in the Northen Bering Sea.2.DGGE analysis showed that the Shannon-wiener's Index value,richness and evenness of bacteria in sediments were clearly higher than those in water.The top Shannon-wiener's Index value and evenness are appeared in DBSA(100m). DBSE(438m) and DBS1(2375m) showed the top richness.37 sequences fell into six bacterial groups.56.8%of them were Proteobacteria.Others were Bacteroidetes (13.51%),Actinobacteria(8.11%),Acidobacteria(8.11%),and Cyanobacteria(2.7%). Delta- Proteobacteria was dominant in sediments in this area.10.81%of the sequences belonged to unidentified bacteria in environment.3.16S rDNA clone libraries of sediments from NEC5,DBSE and DBS1 indicated that bacterial community composition of the sediments had a high diversity.More than 400 clones from the 16S rDNA library fell into 10-13 bacterial groups,including alpha-,beta-,gamma-,delta- and epsilon-Proteobacteria,Acidobacteria, Bacteroidetes,Actinobacteria,Planctomycetes,Nitrospirae,Verrucomicrobia, Chloroflexi,Firmicutes,Chlorobi bacterium,Gemmatimonadetes,Cyanobacterium, Fibrobacteres and Spirochaetes.99.8%of the sequences had a high similarity to uncultured bacteria,and 41%of them showed less than 95%similaritiy to the sequences in GeneBank.Delta- Proteobacteria was dominant in all three 16S rDNA clone libraries,followed by gamma-Proteobacteria and Acidobacteria.