江阴市主要河流夏季浮游藻类的群落结构及多样性

Community Structure and Diversity of Phytoplankton in the Rivers of Jiangyin City

2011年6-8月采集江阴市6条河流的浮游藻类样品，分析其群落结构及物种多样性，并利用多样性指数、指示性类群和硅藻商对水质进行了生物学评价。共检出浮游藻类6门137属种，平均生物量2.38 mg/L，蓝藻、绿藻、硅藻分别占72.3％、10.2％和8.41％。 Shannon-Wiener多样性指数、Margalef丰富度指数和 Pielou均匀度指数的变幅分别为3.34～3.59、4.75～6.40和0.73～0.75，硅藻商变幅为8.3～16.4。多样性指数评价结果表明，水体处于轻或无污染状态；指示性浮游植物类群和硅藻商评价结果表明，河流处于α中污带-β中污滞-多污滞。相关分析表明，Shannon-Wiener多样性指数与理化水质因子不显著相关，与悬浮物SS显著负相关，与总有机碳显著正相关。研究认为，指示性浮游植物类群或硅藻商更适于作为城市河流水质评价的生物指标。

To study the community structure and species diversity of phytoplankton in Jiangyin, samples for 6 main rivers were collected from June to August, 2011. Diversity index, evenness index, indicative groups and diatom quotient were calculated and used to access water quality. 137 taxa, belonging to six phyla, were observed. The average biomass was 2？38 mg/L, including Cyanobacteria （72.3%）, Chlorophyta （10.2%） and diatom （8.41%）. Shannon-Wiener diversity index, Margalef abundance index, Pielou evenness index and diatom quotient were in the range of 3.34-3.59, 4.75-6.40, 0.73-0.75 and 8.3-16.4 respectively. The diversity indexes indicated that the rivers were lightly polluted, while the evaluation result based on diatom quotient and indicative phyla was α, β-type moderate-heavy polluted type. Shannon-Wiener diversity index was negatively correlated with suspended solids and positively with TOC, while has no evidently relationships with chemical indicators. Therefore, diatom quotient and indicative phyla were much more suitable as bio-indicators for accessing the water quality of urban rivers.