• 关键词：蓝藻  细胞密度  南太湖  总氮  东苕溪

• 基金项目：国家水体污染控制与治理科技重大专项(No. 2008ZX07101-006-07);国家高技术研究发展计划(863)项目(No. 2009AA06A417);中日国际合作项目

• 丁源
• 同济大学环境科学与工程学院,长江水环境教育部重点实验室,上海 200092

• 李建华
• 同济大学环境科学与工程学院,长江水环境教育部重点实验室,上海 200092

• 王育来
• 同济大学环境科学与工程学院,长江水环境教育部重点实验室,上海 200092

• 黄亮亮
• 同济大学环境科学与工程学院,长江水环境教育部重点实验室,上海 200092

• 摘要：研究了东苕溪(太湖主要入湖河流)秋季和春季浮游植物的空间分布格局,监测了东苕溪18个采样点的浮游植物叶绿素a含量、细胞密度及种类组成等指标,分析了影响蓝藻时空分布差异的环境因子.结果表明:调查期间,共观察到浮游植物8门60属132种,其中,蓝藻门9属14种,蓝藻细胞密度占浮游植物细胞密度的平均比例为60.3%,蓝藻细胞密度自东苕溪下游至上游呈减小趋势,最高值出现在东苕溪下游距南太湖湖口3 km以内.在秋季,东苕溪下游以铜绿微囊藻(Microcystis aeruginosa)为优势种,春季为水华鱼腥藻(Anabaena　flos-aquae);丝状蓝藻(小席藻)是上游的优势代表种.东苕溪下游蓝藻的绝对优势与特殊的水动力条件、高浓度的营养盐有关.相关性分析表明,蓝藻细胞密度与水深(p<0.01)、总氮(p<0.01)和溶解性总碳(p<0.05)呈显著正相关.

• Abstract：An investigation of the spatio-temporal distribution of phytoplankton community was carried out in the autumn and spring seasons in the East Tiaoxi River. Chlorophyll a concentration, density and composition of phytoplankton were measured. Furthermore, environmental factors influencing the spatio-temporal distribution of cyanobacteria were also investigated. The obtained results showed that a total of 132 taxa in 60 genera of eight phyla was observed, including 14 taxa in nine genera belonged to cyanobacteria, accounting for 60.3% of the phytoplankton density. The highest values of cyanobacteria density were found three kilometers away from the mouth. Microcystis aeruginosa dominated downstream in autumn and Anabaena flos-aquae dominated in spring, while Phormidium tenue dominated upstream. The special hydrodynamic conditions and high concentration of nutrients led to a sustained high abundance of cyanobacteria downsteam the river. Correlation analysis showed that the density of cyanobacteria was significantly correlated with the water depth and total nitrogen concentration (p<0.01), and also positively correlated with dissolved total carbon (p<0.05).

• Key words：cyanobacteria  density  the Southern Taihu Lake  total nitrogen  the East Tiaoxi River

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