辽河口浮游细菌和附着细菌群落结构及多样性分析

Associated and free-living bacteria community structure and diversity of Liaohe estuary

通过MiSeq高通量测序在盐度梯度变化下对辽河口海水中浮游细菌群落和附着细菌群落结构变化特点及与环境因子间相关性进行研究。环境因子包括盐度(S)、温度(T)、溶解氧(DO)、悬浮物(SS)、叶绿素a(Chl a)、细菌生产力(BP)、化学需氧量(COD)、硝酸盐(NO_3-N)、磷酸盐(PO_4-P)、硅酸盐(SiO_3-Si)和铵态氮(NH4-N)。在对辽河口不同盐度区域表层选取代表站位并对其海水环境因子、细菌群落多样性指数、相似度、结构组成进行统计分析。结果显示:由河口向外海过程中水体的S和Chl a逐渐升高,DO、BP、COD以及N、P、Si营养盐的浓度逐渐降低。河口淡水区域β变形菌数量占优势,海水区域α变形菌和γ变形菌的数量逐渐增多。群落结构与环境因子相关性分析结果表明浮游细菌对环境因子变化较为敏感,而附着细菌对环境因子的变化敏感度较低。浮游细菌丰度与S、PO_4-P和BP有显著相关性(P<0.01),相关性系数分别为-0.963、0.996和0.995;附着细菌丰度与SS的相关性最为显著,相关性系数为0.997(P<0.01),此外与NH_4-N和Chl a也有显著相关性。实验结果表明S、PO_4-P、BP、DO和COD是影响浮游细菌丰度的影响因子,浮游细菌丰度与SS、NH_4-N和Chl a关系较为密切。相对附着细菌而言,浮游细菌在河口生态系统物质循环和能量流动方面发挥着更加重要的作用。

Study on planktonic bacterial communities between bacterial community structure and adhesion characteristics of Liaohe estuary waters and environmental factors and the correlation between changes in the salinity gradient through Mi Seq high-throughput sequencing. Environmental factors include salinity（ S）,temperature（ T）,dissolved oxygen（ DO）,suspended solids（ SS）,chlorophyll a（ Chl a）,bacterial productivity（ BP）,chemical oxygen demand（ COD）,nitrate（ NO_3-N）,phosphate（ PO_4-P）,Portland（ SiO_3-Si） and ammonium（ NH_4-N）. Salinity in different regions select representatives Liaohe surface stations and its seawater environmental factors,microbial diversity index,similarity,structure and composition were analyzed. The results showed that S and Chl a increased gradually during the estuary to the offshore waters DO,BP,COD,and N,P,Si nutrient concentrations decreased. Freshwater estuary region β-Proteobacteria numerical superiority,the number of α and γ-Proteobacteria Proteobacteria seaarea is gradually increasing. Community structure and environmental factors correlation analysis showed that planktonic bacteria are more sensitive to changes in environmental factors,and changes in bacterial adhesion is less sensitive to environmental factors. Bacterioplankton abundance and S,PO_4-P and BP were significantly correlated（ P〈0. 01）,the correlation coefficients were-0. 963,0. 996 and 0. 995; SS attachment of bacteria abundance and relevance of the most significant correlation coefficient to 0. 997（ P〈0. 01）,in addition with NH_4-N and Chl a also a significant correlation. Experimental results show that S,PO_4-P,BP,DO and COD are affecting the abundance of planktonic bacteria factor,bacterioplankton abundance and SS,NH_4-N and Chl a closer relationship. In terms of the relative attachment of bacteria,planktonic bacteria play a more important role in the estuarine ecosystem material circulation and energy flows.