南极普里兹湾可培养浮游细菌群落结构研究

摘要

We collected 1 2 sea water samples from three stations in Prydz Bay,near Cape Darnley,Antarctica.Based on the oligographic media,95 strains of Antarctic bacterioplankton were isolated in total.The 1 6S rRNA gene se-quences were determined and analyzed.The isolates fell into three lineages:Alphaproteobactia,Gammaproteobac-teria and Bacteroidetes.The sequences were assigned to 35 operational taxonomic units (OTUs)based on the se-quence analysis.The results showed that Alphaproteobactia was the dominant bacterial group and the proportions were 52.6%-62.5% in the different layers.Analysis using the Shannon diversity index indicated that station P2-1 4 index,located on the continental shelf,was higher than that of stations P2-1 1 and P2-8 located on the slope. There was a positive correlation between the bacteria diversity and biomass as well as productivity of phytoplankton. The Shannon diversity index of the surface was the lowest,and that of the 50-m layer the highest.There was no difference in the Shannon diversity index between the 1 00-m and 200-m layers.The vertical distribution of bacteria was correlated with the nutrient and dissolved oxygen concentrations.In addition,some strains isolated from oligo-graphic media showed low affiliation with the sequences from the described species (less than 97%),suggesting the presence of some novel taxa and specific strains in the Antarctic euphotic layer.Therefore,as shown by this study,the bacterioplankton resources in the Antarctic euphotic layer are rich.The numerous unknown microorgan-isms should be studied further and explored as a valuable resource.%针对南极普里兹湾内达恩利角附近海域的3个测站共12份海水样品，采用寡营养培养基分离培养极地浮游细菌，通过PCR方法获取其中95株细菌的16S rRNA基因序列。序列分析结果表明，分离获得的95株细菌分属α-变形杆菌纲（Alphaproteobactia）、γ-变形杆菌纲（Gammaproteobacteria）和拟杆菌门（Bacteroidetes）3个类群下的35个不同分类单元，其中α-变形杆菌纲为优势细菌，在不同水层中所占的比例为52．6％-62．5％。通过Shannon多样性指数分析发现，南极普里兹湾陆架区测站P2-14多样性指数较陆坡区两测站P2-11和P2-8的高，细菌多样性与浮游植物量和生产力水平呈现正相关。表层细菌Shannon多样性指数最低，50 m水层最高，100和200 m水层多样性指数变化不明显，真光层水体中细菌垂直分布与营养盐和溶解氧浓度存在关联。此外，采用寡营养陈海水培养基，还获得了一些与已报道的16 S rRN A基因序列相似性较低的菌株，它们代表了微生物新物种，可能也是南极真光层特有的细菌。研究工作表明，南极普里兹湾真光层水体中蕴藏着丰富的浮游细菌资源，它们有待保护、开发和利用。