白洋淀浮游植物群落的时空变化及其与环境因子的关系

Spatiotemporal variation of phytoplankton community and its relationship with environ mental factors in the Lake Baiyangdian

浮游植物和环境因子是水生态中重要的组成部分,研究浮游植物与环境因子的相关关系可为白洋淀水资源管理及水生态保护提供理论基础.本研究于2018年非汛期(5月)和汛期(8月)分别对白洋淀淀区8个采样点的浮游植物及环境因子进行调查分析.采用Pearson相关性分析法筛选主要环境因子,分析白洋淀浮游植物群落结构变化和主要环境因子的分布特征,以及两者间的相互关系.结果表明,汛期主要环境因子为溶解氧(DO)、高锰酸盐指数(CODMn)、总氮(TN)和总磷(TP),非汛期主要环境因子为DO、CODMn、氨氮(NH_3-N)和TP.汛期和非汛期检出浮游植物分别为5门38种和6门43种,浮游植物丰度分别为415.30×10~5~1018.14×10~5cells/L和249.62×10~5~454.21×10~5cells/L,优势种分别为6种和10种,且基本为蓝藻和绿藻.浮游植物群落Shannon-Wiener多样性指数(H')、Margalef物种丰富度指数(d M)、Pielou均匀度指数(J)和物种多样性阈值4项指数均表明汛期浮游植物多样性小于非汛期.浮游植物群落特征与水质关联性较强,水质较好区域(如淀区中心) H'和J均较高,反之在水质较差区域(如府河、孝义河等汇入口) H'和J较低.TP和DO是影响汛期浮游植物群落特征的关键因素,CODMn和TP是影响非汛期浮游植物群落特征关键因素.水质评价结果表明白洋淀水质整体处于富营养状态,与2005年以来对白洋淀进行的3次浮游植物生态调查结果相比,淀区浮游植物多样性与均匀度显著下降,表明淀区富营养化程度持续加深.

Phytoplankton and environmental factors were investigated at 8 sampling sites in the Lake Baiyangdian in May and Au gust of 2018,to study their relationship which can provide theoretical basis for water resources management and aquatic ecological protection.The results of Pearson correlation analysis showed that the main environmental factors were dissolved oxygen(DO),permanganate index(CODMn),total nitrogen(TN)and total phosphorus(TP)in flood season while those were DO,CODMn,ammonia nitrogen(NH3 N)and TP in non flood season.Phytoplankton species were detected in 5 phyla,38 species in flood sea son and 6 phyla,43 species in non flood season,respectively.The density of phytoplankton was 415.30×105-1018.14×105 cells/L and 249.62×105-454.21×105 cells/L,respectively.The dominant species were 6 species and 10 species and were mainly cya nobacteria and green algae.The Shannon Wiener diversity index(H′),Margalef species richness index(dM),Pielou evenness index(J)and species diversity threshold of phytoplankton community all indicated that the diversity of phytoplankton in flood sea son was lower than that in non flood season.H′and J were higher in areas with better water quality(such as the center of the Lake Baiyangdian),whereas H′and J were lower in areas with poor water quality(such as the entrance of Fuhe River and Xiaoyi Riv er).TP and DO were the key factors affecting the characteristics of the phytoplankton community in flood season,while CODMn and TP were the key factors affecting the characteristics of the phytoplankton community in non flood season.The results of water quality evaluation showed that the water quality of the Lake Baiyangdian was in eutrophication and the degree continued to deepen com pared with the results of three ecological surveys of phytoplankton since 2005.