天津于桥水库夏季浮游生物调查及群落结构变化

Investigation of summer plankton community structure in Yuqiao Reservoir,Tianjin

为了解于桥水库富营养化状况,于2011年7月对于桥水库水质、浮游生物进行了调查.结果表明,于桥水库综合营养状态指数(TLI(∑))为45.8,属于中营养水平.浮游植物共计8门59种,平均丰度为312.40×104cells/L,平均生物量为5.30 mg/L,以蓝、绿藻为主,优势种为铜绿微囊藻(Microcystis aeruginosa)、水华微囊藻(Microcystis flos-aquae)和单角盘星藻具空变种(Pediastrum simplex var.duodenarium).浮游动物共计16种,平均丰度为53.2 ind./L,平均生物量为11.58 mg/L,以长额象鼻蚤(Bosmina longirostris)和近邻剑水蚤(Cyclops vicinus)为优势种.依据多样性指数、均匀度指数和丰富度指数对于桥水库浮游生物进行评价,表明于桥水库处于中～重污染水平,这与采用TLI(∑)的评价结果较为一致.与历史同期调查结果对比得出,于桥水库浮游植物丰度、生物量增加,浮游动物种类减少,而生物量增加,于桥水库由硅-蓝藻型水库过渡为硅-绿藻型水库,最终向蓝-绿藻型水库演变.

In July of 2011, the water quality and the structures of plankton community were investigated in Yuqiao Reservoir to evaluate its trophic state. The comprehensive trophie level index （ TLI（ ∑） ） is 45.8, which indicates the reservoir is mesotrophic. 59 phytoplankton species in total have been identified. The average phytoplankton abundance is 312.40 ×10^4 cells/L, and the av- erage biomass is 5.30 mg/L. The phytoplankton community is mainly composed by Cyanophyta and Chlorophyta. Microcystis aerug- inosa, Microcystisflos-aquae and Pediastrum simplex var. duodenarium are dominated species. Total of 16 zooplankton species have been identified. The average zooplankton abundance is 53.2 ind./L, and the average biomass is 11.58 mg/L. The zooplankton community is mainly composed of Bosmina longirostris and Cyclops vicinus. Based upon the analyses of the Shannon-Wiener index, Pielou index and Margalef index, the reservoir is between medium pollution level and heavy pollution level, which is similar to the evaluation results of nutritional status using TLI（ ∑ ）. Comparative analysis has been carried out between historical data and the present investigation, and the results show that both abundance and biomass of phytoplankton have been increased, and zooplank- ton species have reduced while zooplankton biomass has increased. This indicates the evolution of Yuqiao Reservoir from a Baeillar- iophyta-Cyanophyta dominated reservoir into a Bacillariophyta-Chlorophyta dominated reservoir, and finally into a Cyanophyta-Chlo- rophyta dominated reservoir.