北黄海微表层细菌丰度与可培养细菌群落结构分析

摘要

为分析海洋微表层这一特殊生境中的细菌类群，于2010—2011年4个航次对北黄海微表层和次表层海水中的总菌丰度、可培养细菌丰度和群落结构进行了分析。采用流式细胞仪测定总菌丰度，平板计数法测定可培养细菌丰度，PCR－16S rDNA 分析可培养细菌的群落结构。结果表明，调查海域微表层海水总菌均值为1．76×106 cell／mL，次表层海水总菌均值为1．07×106 cell／mL。可培养细菌丰度范围是1．00×102～1．70×106 CFU／mL，微表层和次表层可培养细菌所占总菌数量的百分比分别为13．05％和0．45％。微表层对总菌的富集因子（EF）均值为2．02，可培养细菌的 EF 均值为74．16。PCR－16S rDNA 序列分析结果表明，该海域可培养细菌分属变形菌门（Proteobacteria）（94．34％）、厚壁菌门（Firmicutes）（1．89％）、拟杆菌门（Bacteroidetes）（1．89％）和放线菌门（Actinobac-teria）（1．89％）4个类群。本研究初步发现，微表层对细菌具有较强的聚集作用，尤其对可培养细菌聚集作用更为明显。微表层中可培养细菌的群落结构与次表层有所不同，其种类丰富，来源和功能多样。由此可见，微表层独特的生境成就了其独特的微生物类群，其生态功能有待于进一步研究。%In order to learn the bacterial taxa in unique microhabitat of the surface microalyer,the total numbers of bacteria,culturable bacteria and its community structure were investigated from the surface microlayer and subsur-face layer of the northern Yellow Sea.Seawater samples were collected from four sampling times,2010 -2011. The total number of bacteria was determined by flow cytometry.The number of culturable bacteria was determined by the plate count method.PCR-16S rDNA and sequencing analysis were used to analyze the features of commu-nity structure.The results showed that the average numbers of total bacteria are 1.76×106 CFU/mL in the sur-face microlayer and 1.07×106 cell/mL in subsurface layer,respectively.The number of culturable bacteria ranged from 1.00×102 CFU/mL to 1.70×106 CFU/mL.The percentage that culturable bacteria occupies in total bacte-ria were 13.05% and 0.45% in the surface microlayer and subsurface layer,respectively.The enrich factor (EF) of total and cultural bacteria were 2.02 and 74.16 in the surface microlayer.The results showed that the culturable bacteria in this region was attached to four phylogenetic communities:Proteobacteria (94.34%)、Firmicutes (1.89%)、Bacteroidetes (1.89%)and Actinobacteria (1.89%).This research preliminary presented that the sur-face microlayer in seawater has an high enrichment effect on bacteria,especially for culturable bacteria.The bacteri-al communities in the surface microlayer and subsurface layer was different,which reflected in wide range of spe-cies,diversity of source and function.Therefore,the unique bacterial communities of the surface microlayer is gen-erated towing to its special microhabitat.The ecological function of microorganisms in surface microlayer need to be further understood in the future.