永定河山峡与城市段微生物群落结构季节变化

微生物是河流生态系统的重要组成部分，其群落结构会随着时空差异发生改变. 本研究于8月和11月分别采集永定河山峡段和城市段12个点位的样品，采用高通量测序技术研究其群落结构组成及季节演替情况，共检出微生物38门864属，其中蓝细菌门（Cyanobacteria）、放线菌门（Actinobacteria）、变形菌门（Proteobacteria）和拟杆菌门（Bacteroidetes）在群落结构组成中占主要优势. 在时间与空间变化中，8月与11月，山峡段与城市段的永定河微生物群落结构都表现出明显差异，总体来看，8月水体的微生物多样性高于11月份，季节变化使得山峡段微生物群落结构发生了较大变化，而对城市河段的影响不大. 此外，人类活动没有对城市河流的群落多样性造成显著影响，但会使得群落的丰富度显著降低. 

Seasonal variations in microbial community structure in Yongding River

Microorganisms are important in river ecosystem, and the community structures change with time and space. Samples were collected from the gorge section and the urban section in Yongding River in August and November. Composition and seasonal succession of microbial community structures were studied by high-throughput sequencing, the dominant groups were found to be Cyanobacteria , Actinobacteria, Proteobacteria and Bacteroidetes. Microbial communities showed significant differences not only with change of time but also with change of space. Microbial diversity was found higher in August than in November, seasonal variation changed the community of upstream rather than downstream of the river. Human activities were found to have no impact on community diversity but decreased significantly community richness.