珠江口水体浮游细菌种群多样性空间分布特征

Distribution characteristics of bacteriaplankton diversity in the Pearl River Estuary

为认识珠江口水体浮游细菌的多样性分布规律,运用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)和多维尺度分析(MDS)的方法,研究了春季珠江口十个站位表底水层浮游细菌种群16S rRNA基因多样性特征。研究结果表明,珠江口浮游细菌种群具有丰富的基因多样性;不同站位细菌群落结构和优势种群变化显著:大多数站位表底层细菌群落结构比较相似,河口外站位(A12,A14和C5),表底层细菌群落结构差异性较大:多样性分析表明A14,B6和C5站位底层细菌多样性大于表层。遗传发育分析表明,序列归属于变形细菌(Proteobacteria),酸杆菌(Acidobacteria),蓝细菌(Cyanobacteria),厚壁细菌(Firmicutes)和放线菌(Actinobacteria)。变形细菌(Proteobacteria)种类最多,从河口内淡水区到河口外海水区都有大量分布,是珠江口水域占优势的菌群;同时也检测到种类丰富的放线菌(Actinobacteria)的存在,也是珠江口水域的优势菌群。

We investigated the spatial change of bacteriaplankton community structure in the Pearl River Estuary using the denaturing gradient gel electrophoresis （DGGE） and multivariate statistical analysis methods. Results of multidimensional scaling analyses （MDS） were in good agreement with the DGGE band patterns, suggesting that the spatial distribution of bacterial community was significantly different among the investigation stations. Bacterial community had a similar structure between surface and bottom water in most stations, and changed significantly in water layers in the stations of outer estuary. The results also suggested that bacterial community in bottom layer of stations （A14, B6 and C5） had higher diversity than in surface layer. The phylogenetic analysis divided bacteria sequences into five groups, namely Proteobacteria, Acidobacteria, Cyanobacteria, Firmicutes and Actinobacteria, among which Proteobacteria were the dominant bacterial group in the region. In addition, Actinobacteria were also found to be another dominant grouo in the Pearl River Estuary.