小湾库区微生物群落结构多样性与水质状况分析

Microbial Community Diversity and Analysis of Water Quality Status in Xiaowan Reservoir

为了解小湾库区不同水域的微生物多样性及微生物群落与生态环境的关系,2019年在库区选取6个采样点(W1~W6),通过16SrDNA基因扩增和高通量测序,分析库区微生物群落结构组成与多样性差异及水质状况。结果显示,小湾库区水体整体呈偏碱性,COD含量为14.79~24.47 mg/L,TN浓度为0.53~2.39 mg/L,TP浓度为0.14~1.17 mg/L。不同采样点的微生物Chao1指数、覆盖率均较高,Shannon指数为3.42~4.48,Simpson指数为0.030~0.092,反映出各采样点微生物群落多样性丰富,其中群落丰富度以W6区域最高。各采样点的微生物主要有变形菌门(Pro-teobacteria)、蓝细菌门(Cyanobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)和绿弯菌门(Chloroflexi),丰度之和达90%以上,以变形菌门为优势菌;在属水平上,以不动杆菌属(Acinetobacter)为第一优势菌属。PCoA分析发现,W5和W6聚为一类,W1~W4聚为另一类,并具有显著差异。研究表明,小湾库区水质整体良好,但部分区域已出现富营养化现象,且有扩散趋势,需采取环境治理措施。建议通过合理放养、适度捕捞的方式充分利用水域天然饵料资源,在保证小湾库区正常水力发电的前提下,适度开发库区渔业资源。

Xiaowan reservoir is located in the middle-lower reaches of Lancang River.In this study,we explored the microbial diversity of different waters in the Xiaowan reservoir area and analyzed the rela-tionship of the microbial community with the local ecological environment.Our aim was to provide basic environmental monitoring data for aquatic ecosystem evaluation.Water samples were collected at six sam-pling sites(W1-W6)during 2019 in Xiaowan reservoir,along the main stem of Lancang River and one tributary,Heihui River.Gene amplification of 16S rDNA and high-throughput sequencing were used to analyze the structural composition,diversity differences of the microbial communities and water quality in the reservoir area.The water in Xiaowan reservoir was alkaline,high oxygen levels,a COD range of 14.79-24.47 mg/L,TN range of 0.53-2.39 mg/L and TP range of 0.14-1.17 mg/L.The Chao1 indices and coverage rates of the microbial communities at different sampling sites were high,and the Shannon and Simpson indices were in the range of 3.42-4.48 and 0.030-0.092,respectively,indicating that the di-versity of microbial community in the Xiaowan reservoir area was rich,and highest at the W6 site.The microbial community primarily consisted of Proteobacteria,Cyanobacteria,Actinobacteria,Bacteroidetes and Chloroflexi,accounting for more than 90%of the total abundance,and Acinetobacter was the most dominant group at the genus level.Proteobacteria was the most dominant taxon at W3 and W6,account-ing for 48.31%-55.30%of the total abundance at both sites.Cyanobacteria was the most dominant taxon at W1,W2,W4 and W5,accounting for 37.49%-43.50%of the total abundance at these sites.Principal Component Analysis(PCoA)shows that the microbial communities at W5 and W6 were clustered into a single group,while the microbial communities at W1,W2,W3 and W4 were clustered into another signif-icantly different group.The overall water quality of Xiaowan reservoir was good,but eutrophication has occurred in some areas and is tending to spread.Therefore,prevention and control measures should be tak-en immediately,and environmental monitoring should be carried regularly out in Xiaowan reservoir.We also suggest moderate development of the fishery resource with appropriate fish release and fishing to make use of the natural small fish resources in the investigated area.