Abstract:Abstract:[Objective] To reveal the diversity of marine bacteria in disparate sites of the Northern Yeallow Sea. [Methods] Bacterial community structure and diversity within seawaters and sediments at two stations in the Northern Yellow Sea were investigated and assessed by the 16S rDNA clone library and the denaturing gradient gel electrophoresis (DGGE) techniques. [Results] The 16S rDNA clone library analysis indicated that the bacteria were abundant in the waters and sediments, and most of them were unknown. Phylogenetic analysis showed that the proteobacteria were the dominant group both in the sediments and waters, γ-proteobacteria and δ-proteobacteria were dominant in the sediments, α-proteobacteria were dominant in the water. However, all subphyla of proteobacteria presented phylogenetical divergence at the two sites. The clustering analysis on the DGGE patterns revealed that the dominant groups within the waters and sediments in shore were similar to each other, whereas that in the offshore were different. [Conclusion] The microbial diversity differed due to the geographical location and living medium; and the microbial distribution depended on the environment factors.