湖泊科学2024，Vol.36Issue(4)：1001-1013,13.DOI:10.18307/2024.0411
鄱阳湖浮游植物时空变化特征及其对极端洪枯事件的响应
Spatial and temporal characteristics of phytoplankton in Lake Poyang and its response to extreme flood and drying events
摘要
Abstract
As the largest freshwater lake in China,the water ecological health status of Lake Poyang has been highly concerned.In recent years,extreme floods and droughts occurred frequently in Lake Poyang.Phytoplankton growth has changed significantly un-der the influence of extreme floods and droughts.In order to investigate the spatial and temporal dynamics of phytoplankton,and to explore the influence mechanism of environmental factors on phytoplankton and the influence of extreme flood and drought events on phytoplankton in Lake Poyang,structural equation modeling was used to develop the influence path model between phytoplankton and environmental factors,and to quantify the extent of the influence of environmental factors on phytoplankton.The results showed that the phytoplankton in Lake Poyang was dominated by cyanobacteria and green algae with seasonal variation.The most critical factors affecting the abundance of phytoplankton were physical factors(water temperature＞pH＞secchi depth＞dissolved oxygen),followed by nutrients(total nitrogen＞nitrate nitrogen＞total phosphorus＞phosphate).Phytoplankton preferred high temperature,nu-trients and pH.In the extreme flood in 2020 and the extreme high temperature and drought in 2022,the density of phytoplankton were mainly affected by physical factors such as water temperature,dissolved oxygen and secchi depth.For nutrients,the main lim-iting factors were phosphorus and nitrogen.Compared with normal years,in the extreme flood year,Lake Poyang suffered from the increase of incoming water,rainfall and lake water volume.The dilution effect exceeded the promotion of phytoplankton growth by water temperature,dissolved oxygen and secchi depth,resulting in the decrease of phytoplankton density and biomass.Among the nutrients,phosphorus was the main limiting factor.In extreme high temperature and drought years,due to the reduction of incom-ing water and the rapid evaporation of lake water,the concentration effect exceeded the inhibitory effect of water temperature and secchi depth on phytoplankton growth,resulting in a significant increase in phytoplankton density and biomass.Meanwhile,the im-pacts of nutrients on phytoplankton were enhanced.This study showed the significant impacts of the extreme flood and drought e-vents on phytoplankton in Lake Poyang.Determining the mechanism of their impacts on phytoplankton can provide scientific sup-port for phytoplankton monitoring and management under extreme meteorological events.关键词
鄱阳湖/浮游植物/结构方程模型(SEM)/环境因子/极端洪枯Key words
Lake Poyang/phytoplankton/structural equation modeling(SEM)/environmental factors/extreme flood and drought引用本文复制引用
李文轩,蒋名亮,徐力刚,胡颂平,游海林,周权平,陈孜,张琳..鄱阳湖浮游植物时空变化特征及其对极端洪枯事件的响应[J].湖泊科学,2024,36(4):1001-1013,13.基金项目
国家自然科学基金项目(41971137,U2240224,42001109,42307106,42261020)、江西省科技计划项目(20213AAG01012,20212BBG71002,20222BCD46002,20224BAB213035)、江西省青年人才培养项目(20204BCJL23040)、中国地质调查局地质调查项目(DD20221728)和江西农业大学2023年大学生创新创业项目(S202310410095,S202310410098,X202310410304)联合资助. （41971137,U2240224,42001109,42307106,42261020）
