南水北调东线山东境内调蓄湖库蓝藻种群分布特征及环境驱动因子

Distribution Characteristics and Environmental Driving Factors of Cyanobacteria Community in Impounded Lakes and Reservoirs in Shandong on the East Route of South-to-North Water Diversion Project

为掌握南水北调东线山东境内调蓄湖库在工程运行前后蓝藻种群的分布情况及其环境驱动因子,于2010~2019年的5~11月对南四湖、东平湖、大屯水库、东湖水库和双王城水库进行藻类和水环境调查.共检出浮游蓝藻44种,其中丝状蓝藻23种.湖泊假鱼腥藻、拉氏拟柱孢藻、铜绿微囊藻和惠氏微囊藻在各调蓄湖库的检出频次和密度均较高,是主要有害蓝藻种.通过分析各调蓄湖库蓝藻种群的分布特征,发现丝状蓝藻在水力扰动较大水体中的生长优势较为明显,应成为日后调蓄湖库蓝藻风险防控的重点.Pearson相关性分析和广义线性拟合曲线结果显示,总氮、总磷、水温和水深是影响调蓄湖库主要有害蓝藻种生长的主要环境驱动因子.氮磷营养盐对于有害蓝藻种的生长具有显著的促进作用.湖泊假鱼腥藻具有良好的温度适应性,在夏初秋末仍能成为优势种,而当水温大于25℃时,拉氏拟柱孢藻、铜绿微囊藻和惠氏微囊藻具明显的生长优势.此外,较小的水深更利于拉氏拟柱孢藻的生长.建议在加强控制湖库氮磷营养盐输入的基础上,在夏初和秋末对湖泊假鱼腥藻进行重点监控,并在高温时期密切关注浅水区拉氏拟柱孢藻的生长情况,保障水质安全.

To investigate the distribution characteristics of the cyanobacteria community and the driving factors in impounded lakes and reservoirs in Shandong on the east route of the South-to-North Water Diversion Project,monthly samples of phytoplankton and the aquatic environment from Nansi Lake,Dongping Lake,Datun Reservoir,Donghu Reservoir,and Shuangwangcheng Reservoir were collected from May to November during 2010 to 2019.A total of 44 planktonic cyanobacteria taxa were identified with 23 filamentous cyanobacteria taxa.Pseudanabaena limnetica,Cylindrospermopsis raciborskii,Microcystis aeruginosa,and Microcystis wesenbergii were the dominant harmful cyanobacteria species,with a high detection frequency and abundance in all lakes and reservoirs.By analyzing the distribution characteristics of the cyanobacteria community in impounded lakes and reservoirs,we found that filamentous cyanobacteria had growth advantages in the water with large hydraulic disturbances,which should be the key points of cyanobacteria prevention and control in the future.Pearson correlation analysis and generalized linear fitting curve results showed that total nitrogen,total phosphorus,water temperature,and water depth played a key role in affecting the growth of P.limnetica,C.raciborskii,M.aeruginosa,and M.wesenbergii.The nitrogen and phosphorus nutrients could promote the growth of harmful cyanobacteria.Due to the good temperature adaptability,P.limnetica could still become the dominant species in early summer and late autumn,and C.raciborskii,M.aeruginosa,and M.wesenbergii had growth advantages when the water temperature was higher than 25℃.In addition,shallow water was more conducive to the growth of C.raciborskii.It was suggested that based on strengthening of the control of nitrogen and phosphorus nutrient input in lakes and reservoirs,the key monitoring of P.limnetica in lakes should be conducted in early summer and late autumn,and the growth of C.raciborskii in shallow water areas should be paid close attention in the high temperature period to ensure the safety of water quality.