【作者】 张婷；

【导师】 黄小兰；

【作者基本信息】 江西师范大学 ， 环境地理学， 2018， 硕士

【摘要】 鄱阳湖的水环境效应在全球影响深远,维护鄱阳湖的生态系统平衡尤为重要。微生物是水生态系统内物质循环的主要驱动者,影响和调节着水体的环境质量。鄱阳湖河湖交错带作为重要的污染净化区和缓冲区,拥有更加丰富的微生物多样性。本课题通过研究2016年干、湿两季鄱阳湖河湖交错带表层水体的水质理化指标、微生物多样性指数和微生物群落组成结构,得出以下结论:(1)鄱阳湖河湖交错带表层水体的理化性质在干、湿季存在一定的空间差异和时间差异,整体来看时间差异大于空间差异。人类活动频繁的区域总氮和总磷含量均较高,表明人类活动对鄱阳湖河湖交错带表层水体水质的影响较为明显。(2)通过高通量测序数据分析,2016年湿季的11个样点测定出333,794条有效序列,得到5,796个OTU,共检测出34门、74纲、154目、254科、413属和678种;2016年干季的13个样点测定共出469,181条有效序列,得到9,959个OTU,共检测出44门、101纲、193目、348目、651科和1107属。(3)鄱阳湖河湖交错带干、湿两季均在门分类上以变形菌门占绝对优势,在纲分类上均以放线菌纲和β-变形菌纲为优势类群,表现出的空间分布差异在时间变化上更为明显。在属分类水平上,都以放线菌门下的hgcI_clade占据绝对优势,但在干季中的比重有明显减少。(4)对所测的环境因子和微生物群落组成结构进行冗余分析,发现大部分优势菌门与环境因子之间的解释量较好,两者存在相应的正负相关性。说明鄱阳湖河湖交错带表层水体的理化指标与微生物群落结构呈现出的时空分布差异之间存在一定相关性。(5)鄱阳湖河湖交错带不同样点间的微生物群落结构存在较为密切的联系,但个别样点在空间表现上仍存在明显差异,且干季的空间差异明显要大于湿季。更多还原

【Abstract】 The effect of water environment in Poyang Lake is profound and lasting around the world,so it is particularly important to maintain the balance of the ecological system in Poyang Lake.Microorganism is the main driver of the material circulation in the water ecosystem,which affects and regulates the environmental quality of the water body.As an important pollution area and buffer zone,Lake-River Ecotone of Poyang Lake has more abundant microbial diversity.In this study,we studied the physicochemical properties,microbial diversity index and bacterial community composition of surface water bodies in the Lake-River Ecotone of the Poyang Lake during the wet season and dry season,The conclusion is as follows:(1)The physical and chemical properties of the surface water in the Lake-River Ecotone of the Poyang Lake existed some spatial differences and time differences during the wet season and dry season,and the time differentiation was greater than the spatial differentiation on the whole.The content of total nitrogen and total phosphorus in the region with frequent human activities was high,it shows that human activities have a more obvious effect on the water quality of the surface water body of the LakeRiver Ecotone of the Poyang Lake.(2)Eleven samples collected from September were subjected to high throughput sequencing to obtain 333,794 effective base sequences,and 5,796 OTUs were obtained,and it was found that all the bacteria in the samples were 34 phylum,74 class,154 order,254 family,414 genus and 678 species.Thirteen samples collected from December were subjected to high throughput sequencing to obtain 469,181 effective base sequences,and 9,959 OTUs were obtained,and it was found that all the bacteria in the samples were 44 phylum,101 class,193 order,348 family,652 genus and 1,107 species.(3)Proteobacteria was the dominant species of phylum in the wet and dry season of the Lake-River Ecotone of the Poyang Lake,which accords with the basic characteristics of microbial composition in typical freshwater bodies.Actinobacteria and betaproteobacteria were the dominant groups in the class classification,and its spatial distribution differentiation was more obvious in the temporal change.The hgc I_clade under the actinobacteria was the dominant groups in the species classification,but its proportion is obviously reduced in the dry period.(4)Redundancy analysis of environmental factors and microbial community structure revealed that the explaining variable between the dominant bacteria and environmental factors were better,and it existed the corresponding positive correlation and negative correlation.This illustrated that there was a certain correlation between the physical and chemical indexes of the surface water body of the Lake-River Ecotone of the Poyang Lake and the spatial and temporal distribution of microbial community structure.(5)There was a close relationship between the microbial community structure of different sample points of the Lake-River Ecotone of the Poyang Lake,but individual sample points are still expressed the significant differences in space distribution,and the spatial difference in dry season is obviously greater than that in wet season.更多还原