Spatial distribution of bacterioplankton community composition and their diversity in Lake Fuxian during thermal stratification period

水体垂向分层是深水湖泊一个重要的特征，这不仅影响水体理化环境因子，而且影响水生生物组成的垂向分布，但是对不同水层水体细菌的多样性和群落结构组成的形成与维持机制知之甚少. 本研究以抚仙湖为研究对象，在水体热力分层期间采集不同位点、不同水层水样，借助16S rDNA Illumina Miseq高通量测序技术，探究水体细菌多样性和群落结构组成的空间分布特征及关键影响因子. 研究结果表明：(1)抚仙湖北部湖心在水深15~40 m处出现温跃层，温度由23℃降至15℃，其余理化环境因子也存在明显的垂向分层现象；与垂向差异相比，表层水体各理化因子在水平方向上的差异相对较小. (2)在水平方向上，南部湖心表层水体细菌alpha多样性(Operational Taxonomic Unit数目和Faith's phylogenetic diversity)最高；在垂向上，水体细菌alpha多样性随着采样水深的增加呈现单峰分布，在30和40 m水层最高；水体细菌alpha和beta多样性的垂向差异均显著大于水平方向差异. (3)表层水体细菌主要由Actinomycetales、unidentified Cyanobacteria、Burkholderiales和Sphingobacteriales组成；温跃层中以Pseudomonadales为主；均温层的优势菌群为unidentified Chloroflexi、Actinomycetales和Burkholderiales. 典范对应分析表明溶解性有机碳、溶解氧、硝态氮、氨氮和总磷浓度是影响细菌群落组成的主要环境因子.;Deep lakes are typically characterized by thermal stratification throughout the year, except for a short mixing period in winter. This vertical partitioning has important effects on many biotic, physical and chemical characteristics of water column. However, at present, little is known about how these changes affect distribution bacterioplankton community diversity. In this study, Lake Fuxian with relatively long every was chosen investigation distribution, diversity composition August 25th, 2013. 16S Miseq high-throughput sequencing technology performed DNA extracted from samples collected different locations depths. The results showed that: (1) A thermocline appeared lake center northern part depth 15-40 m, temperature dropping 23℃ to 15℃. Other factors also obvious pattern. Horizontally, there no significant difference physicochemical features. (2) horizontal direction, alpha diversities plankton bacteria (the number Operational Units Faith's diversity) surface southern highest; gradually increased increase sampling depth, topping depths 30 m or 40 then decreased; beta direction significantly greater than those direction. (3) epilimnion were mainly composed Actinomycetales, unidentified Cyanobacteria, Burkholderiales Sphingobacteriales; relative abundance Pseudomonadales became dominant; Chloroflexi, Actinomycetales dominant bacterial taxa hypolimnion. canonical correspondence analysis demonstrated that concentrations dissolved organic carbon, oxygen, nitrate, ammonium total phosphorus environmental variables shaping community's