三峡水库小江回水区水华暴发期浮游植物群落结构及其与环境因子的关系  

Community structure of phytoplankton in different water layers and its relationship with environmental factors during the period of algal bloom in Xiaojiang River backwater area of Three Gorges Reservoir

作　　者：胡莲[1] 郑志伟[1] 杨志[1] 杨晴 邹曦[1] 万成炎[1] 张云昌 Hu Lian;Zheng Zhiwei;Yang Zhi;Yang Qing;Zou Xi;Wan Chengyan;Zhang Yunchang(Key Laboratory of Ecological Impacts of Hydraulic-projects and Restoration of Aquatic Ecosystem of Ministry of Water Resources,Institute of Hydroecology,Ministry of Water Resources and Chinese Academy of Sciences,Wuhan 430079,P.R.China;Department of Three Gorges Project Management,Ministry of Water Resources,Beijing 100000,P.R.China)

机构地区：[1]水利部中国科学院水工程生态研究所,水利部水工程生态效应与生态修复重点实验室,湖北省水生态保护与修复工程技术研究中心,武汉430079 [2]水利部三峡工程管理司,北京100000

出　　处：《湖泊科学》2024年第4期1025-1035,I0003-I0005,共14页Journal of Lake Sciences

基　　金：国家重点研发计划项目(2022YFC3203905);三峡工程运行安全综合监测系统-库区维护和管理基金项目(2136703);中国三峡集团有限公司项目(0799253);水利部重大科技项目(SKR-2022015)联合资助。

摘　　要：三峡水库蓄水以来,支流水华频发,尤以小江情况最为严重,给三峡库区的生态安全带来较大隐患。为探究支流水华暴发特征和主控因素,于20142021年小江水华暴发期间在小江高阳江段进行浮游植物及环境因子调查,并使用单因素方差分析、聚类分析、百分比相似性分析以及基于距离的线性模型等方法,对小江水华暴发期间浮游植物和环境因子在不同年份不同水层间的差异以及二者的关系进行研究。结果表明:小江水华暴发期内,浮游植物的种类数在43~70种之间,其中2015年蓝藻种类数明显减少,2018年以后硅藻种类数明显减少;采样期间浮游植物平均细胞密度在0.66×10^(6)~61.28×10^(6)cells/L之间,同期表层细胞密度明显高于中层和底层;各层水体间水华微囊藻、铜绿微囊藻、不定微囊藻等10种藻的密度存在明显差异,是主要差异种;显著影响表层、中层和底层浮游植物群落结构变动的环境因子是水位的日平均变幅;水位的日平均变幅与藻类优势种拟合关系显示,当日水位下降幅度在0.5 m以上时,浮游植物平均密度会呈指数级减少。研究结果可为三峡库区支流水华的防控提供数据支持。Since the impoundment of the Three Gorges Reservoir,severe algal blooms frequently occurred in tributaries especially in the Xiaojiang River,increasing the ecological vulnerability of the Three Gorges Reservoir.To examine the characteristics of tributary algal blooms and its driving factors,a sampling program was conducted in Gaoyang section of Xiaojiang River from 2014 to 2021.Based on the data set,statistical methods such as One-way ANOVA,cluster analysis,percentage similarity analysis,and distance-based linear model were employed to explore the variations and correlations between phytoplankton and environmental factors across different water layers and years during the bloom period.The results showed that the number of phytoplankton species had a range from 43 to 70 species during the bloom period,with a significant decrease in the number of cyanobacteria species in 2015.After 2018,the number of diatom species decreased significantly.The average cell density in each year was between 0.66×10^(6)and 61.28×10^(6)cells/L,and showed a fluctuating upward trend from year to year.The average cell density in the surface layer was obviously higher than that in the middle and bottom layers.The concentrations of ten algal species,including Microcystis flos-aquae,Microcystis aeruginosa,and Microcystis indeterminata,had large variations throughout different water layers of the water column.The daily average fluctuation of water level is a crucial environmental factor for the composition of phytoplankton communities in surface,middle,and bottom water layer.The relationship between the daily average fluctuation of water level and the dominant algal species showed an exponential decrease in the average phytoplankton density,in case that the daily water level declined by more than 0.5 m.This study can provide data support for controlling algal blooms in the Three Gorges Reservoir.

关 键 词：三峡水库 小江 水华暴发 浮游植物 群落结构 水位变动 

分 类 号：X524[环境科学与工程—环境工程]