南海西沙海槽沉积物细菌多样性初步研究

对来自南海西沙海槽的深海沉积物进行总DNA提取，并构建细菌16S rDNA文库。细菌16S rDNA系统发育分析表明沉积物中细菌分属4个类群：变形杆菌(Proteobacteria)、浮霉菌(Planctomycene)、低G+C含量革兰氏阳性菌和放线菌(Actinobacteria)，它们分别占总体的49%、22%、22%和7%。Proteobacteria类群又以δ Proteobacteria亚群占优势，其他分属α 和γ Proteobacteria亚群。Planctomycene和低G+C含量革兰氏阳性菌两个常见于浅海的类群，在西沙海槽沉积物的丰度高于其他深海沉积物，可能是随沉积物被浊流搬运至海槽。

A Preliminary Study on the Diversity of Bacteria in the Xisha Trough Sediment, the South China Sea

The bulk DNA was isolated from bacterial habits in sediments of the Xisha trough, the south China sea. Using a pair of primers special for most common bacteria, the researchers amplified partial sequences of bacterial 16S rDNA gene and thus constructed a 16S rDNA clone library. A total of 22 clones were used to reconstruct the bacterial 16S rDNA phylogenetic tree. Guided by the phylogenetic tree, bacteria fell into four main lineages: Proteobacteria, Planctomycene, Actinabacteria and Low G+C Gram positive bacterium. Among them, 49% belonged to Proteobacteria, 22% to Planctomycene,the same to Low G+C Gram positive bacterium,and the remaining 7% to Planctomycene. The group of Proteobacteria clustered in three subgroups: α , γ and δ Proteobacteria, and the subgroup of δ Proteobacteria predominated in them. Furthermore, the abundance of two groups of Planctomycene and Low G+C Gram positive bacterium, living commonly in shallow marine deposits, was higher in sediments of the Xisha Trough than in other deep sea sediments. Most members of these two groups were probably brought from the shelf into the trough sediment by the turbid.