太湖梅梁湾湖岸带浮游植物群落演替及其与水华形成的关系

利用2009～2010年周年观测数据,结合江苏太湖湖泊生态系统研究站15年监测数据,分析了太湖梅梁湾湖岸带浮游植物群落演替及其与蓝藻水华形成的关系.50次周监测结果表明:蓝藻门(Cyanophyta)、绿藻门(Chlorophyta)、硅藻门(Bacillariophyta)分别占浮游植物总生物量的60%、16%和22%.冬春季绿藻、硅藻为主要优势种,夏秋季蓝藻门的微囊藻占绝对优势.4月下旬～6月初,平均温度低于20℃,蓝藻没有大规模生长,硅藻门、绿藻门生物量急剧降低,总生物量小于1mg·L^-1;随后温度超过25℃,蓝藻迅速增长并很快成为绝对优势,蓝藻增加滞后于绿藻、硅藻的减少.在营养盐充足、物理因素合适的条件下,浮游植物群落结构自然演替是蓝藻水华形成的主要原因之一.

Succession of phytoplankton structure and its relationship with algae bloom in littoral zone of Meiliang Bay,Taihu Lake

To elucidate the relationship between phytoplankton structure indicators in littoral zone of Meiliang Bay,Taihu Lake.Weekly results showed that Cyanophyta,Chlorophyta and Bacillariophyta were three dominant groups,constituting 60%,16% and 22% of annual average total phytoplankton biomass, respectively.Chlorophyta and Bacillariophyta were the main dominant species in winter and spring,while in summer Cyanophyta was the only dominant species.From April to June,average water temperature(WT)was under 20℃,the biomass of Chlorophyta and Bacillariophyta decreased,and Cyanophyta biomass was low,with the total biomass lower than 1 mg·L^-1.As WT increased above 25℃, Cyanophyta proliferated rapidly and became the only dominant species.Under the condition of enough nutrients and suitable meteorological factors,succession of phytoplankton structure contributed significantly to algae blooms.