Abstract: The phylogenetic diversity of bacteria associated with Alexandrium catenella was studied by 16S rDNA gene sequences. With culture-independent approach, the total bacterial DNA was extracted from A. catenella. 16S rDNA genes were amplified by PCR, and a 16S rDNA clone library was constructed. The phylogenetic diversity of the bacteria was determined by RFLP-16S rDNA sequencing of cloned DNA fragments. A total of 84 cloned 16S rDNA fragments were digested with restriction endonucleases HaeⅢ, and 30 different PFLP types were obtained. Fifty cloned partial sequences were acquired, most of which were related to Proteobacter, and mainly attributed to α-Proteobacteria and Bacteroidetes in the phylogenetic tree. In α-Proteobacteria, Roseobacter sp. was the dominant clade. This study demonstrated the prolific bacterial diversity of A. catenella.

Key words: Ecosystem, Service, Value, Remote sensing, Measurement