Diversity of bacteria isolated from the South China Sea sediments

Abstract:

[Objective] To isolate bacteria from Nansha area of South China sea, [Methods] Sediment samples of 22 sites were used. Bacterial isolation was conducted on plates of marine medium, followed by 16S rRNA identification and phylogenetic analysis. [Results] In total 349 bacteria were obtained, belonging to 87 species. Analyses of 16S rRNA sequence showed that Bacillus and other spore-forming bacteria occupied the majority of isolates in 10 sites. Bacillus was the most abundant bacterium and of high diversity; with 34 species and 8 possible novel species. Halobacillus also occurred frequently while other spore-forming bacteria including Brevibacillus, Paenibacillus, Pontibacillus and Thalassobacillus were also found, but less occurred in this area. In addition to these low-G+C-content bacteria, γ-Proteobacteria were the second subgroup of high occurrence, among which Pseudomonas, Marinobacter and Alcanivorax were relatively abundant. Generally, isolates of 750-2000m deep mainly consist of low-G+C-content bacteria, while mainly composed of gamma-Proteobacteria when the depth is over 2000m. [Conclusion] Marine sediments of South China Sea are rich in spore-forming bacteria, which deserve further study and exploitation.