丹江口水库枯水期浮游细菌群落组成及影响因素研究

摘要

为了解丹江口库区南水北调中线工程通水后浮游细菌群落组成及影响因素,于2016枯水期(1月)对丹江库区内5个典型生态点位表层水样进行采集.水质监测结果表明库区水质总体较好,除总氮和高锰酸盐指数外,其他各项指标符合Ⅰ类水标准要求.总氮(TN)和高锰酸盐指数(CODMn)为库区的主要污染因子,水体整体处于中营养状态.采用高通量测序技术对浮游细菌群落组成进行研究,结果表明主要由放线菌门(Actinobacteria)、变形菌门(Proteobacteria)、蓝藻门(Cyanobacteria)、拟杆菌门(Bacteroidetes)、疣微菌门(Verrucomicrobia)、壁厚菌门(Firmicutes)、酸杆菌门(Acidobacteria)等22个门和323个属组成.5位点样品具有丰富的群落组成,浮游细菌群落多样性排序为:黑鸡嘴＞台子山＞库心＞宋岗＞渠首.对浮游细菌群落组成与环境因子的关系进行典范对应分析(CCA),结果表明:T、pH值、NH+N、SD显著影响浮游细菌群落结构.%The Danjiangkou reservoir is the main source of water for the "middle-route" of the South to North Water Diversion Project in China.Its water quality directly affects the safety of drinking water for residents along this route.In this study,15surface-water samples were collected from the reservoir at low-water period (January) in 2016,and 12 essential environmental factors were investigated.The results showed that the water quality in the reservoir was strongly influenced by total nitrogen (TN) and the permanganate index,with the water quality being ranked at ⅣV or Ⅱ for all locations.The water in this reservoir was in the mesotrophic state.The high-throughput sequencing approach was adopted to analyze the distribution characteristics of the community structure and diversity of bacterioplankton and their relationship to environmental factors.Phylogenetic analysis based on 16S rDNA sequences showed that bacterioplankton could be divided into 22 major phylogenetic groups.The dominant phylogenetic groups included Actinobacteria,Proteobacteria,Cyanobacteria,Bacteroidetes,Verrucomicrobia,Firmicutes,and Acidobacteria.At the genus level,the dominant phylogenetic groups included CL500-29 marine group,hgcⅠ clade,Fluviicola,Sediminibacterium,Flavobacterium,LD28 freshwater group,Limnohabitans,Synechococcus,Bacillus,and Cyanobacteria norank.Diversity of the bacterioplankton community in the Danjiangkou reservoir can be ranked in the following order:Heijizui ＞Taizishan ＞Kuxin＞Songgang＞Qushou.The results of canonical correspondence analysis (CCA) for the relationship between the 22 phyla of bacterioplankton and 12environmental factors showed that the T,pH,NH4+-N,and SD were the main environmental factors affecting the distribution characteristics of the bacterioplankton community.