秋冬季温度降低对微囊藻衰亡和沉降的作用机制  

Mechanism of temperature reduction in autumn and winter on decline and sedimentation of Microcystis

作　　者：张昱 朱伟[1] 冯甘雨 王若辰[1] 薛宗璞 吕艺 ZHANG Yu;ZHU Wei;FENG Ganyu;WANG Ruochen;XUE Zongpu;LYU Yi(College of Environment,Hohai University,Nanjing 210098,China;College of Environment Science and Engineering,Tongji University,Shanghai 200092,China;College of Hydrology and Water Resources,Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学环境学院,江苏南京210098 [2]同济大学环境科学与工程学院,上海200092 [3]河海大学水文水资源学院,江苏南京210098

出　　处：《水资源保护》2024年第1期149-156,共8页Water Resources Protection

基　　金：江苏省水利科技项目(2021009);江苏省研究生培养创新工程研究生科研创新计划(B200203049)。

摘　　要：为明确温度降低对微囊藻衰亡和沉降的影响,对贡湖微囊藻水华的消退过程进行了监测,同时开展了室内低温培养试验。结果表明:室内试验模拟结果与野外秋冬季的现象基本吻合,微囊藻一般在温度低于15℃时衰亡,低于12.5℃大量沉降;温度降低造成群体粒径显著减小,与群体内死亡的藻细胞数量有关,当死亡率达到25%~45%时,大群体普遍开始解体并分散成小群体;微囊藻在低温下重力密度持续增长,最终失去自主上浮能力;秋冬季降温初期微囊藻沉降主要由群体小型化和松散化导致,重力密度增大很可能是降温后期微囊藻沉降的主要原因。In order to clarifying the impact of temperature reduction on the decline and sedimentation of Microcystis,the decline process of Microcystis bloom in Gonghu Lake was monitored and low temperature culture experiments were conducted.The results show that the laboratory simulation results are basically consistent with the phenomenon in the field in autumn and winter.Microcystis generally declines at temperature below 15℃and sinks in large numbers below 12.5℃.The temperature reduction leads to a significant decrease in the size of the Microcystis colonies,which is related to the number of dead algal cells within the colony.When the mortality rate reaches 25%~45%,the large colonies will generally begin to disintegrate and disperse into small colonies.Gravity density of Microcystis continues to increase at low temperatures,and it eventually loses its ability to autonomously float to the surface.The initial decline in sedimentation of Microcystis in autumn and winter is mainly caused by colonies miniaturization and loosening,and the increase of gravity density is likely to be the main cause of Microcystis sedimentation in the later stages of temperature reduction.

关 键 词：低温 微囊藻 衰亡 群体 重力密度 贡湖 

分 类 号：X524[环境科学与工程—环境工程]