于桥水库浮游植物群落结构及与水质关系研究

Relationship of Phytoplankton Community Structure and Water Quality in Yuqiao Reservoir

为研究于桥水库浮游植物群落结构及其与环境因子的关系,并确定水体营养程度,于2012年5、7、8、9、11月对于桥水库浮游植物及相关水质因子进行调查分析,运用水质指标、生物指标及综合营养状态指数法（TLI（∑））对水体营养状态进行了评价,同时应用冗余分析（RDA）研究了影响浮游植物群落结构的主要环境因子。结果表明,浮游植物共计7门、123种（属）,其中绿藻种类最多,为64种,占总数的52.0%。优势种以蓝藻和绿藻为主,分别为铜绿微囊藻（Microcystis aeruginosa）、水华微囊藻（Microcystis flos-aquae）、衣藻属（Chlamydomonas sp.）和单角盘星藻（Pediastrum simplex）。浮游植物丰度为369.75×10^4-4 636.64×10^4个/L,平均1 353.00×10^4个/L;生物量为1.12-13.58 mg/L,平均4.61 mg/L。浮游植物群落结构季节变化明显,其种数、丰度、生物量由大到小排序结果均显示,夏季汛期（7、8、9月）〉秋季（11月）〉春季（5月）。水质指标、生物指标及TLI（∑）评价结果表明于桥水库水质处于中-富营养状态,且夏季汛期富营养化程度整体高于春季和秋季。RDA结果显示,p H、悬浮物、水温、氨氮和总磷是影响丰度变化的主要环境因子,其中p H与蓝藻丰度相关性较大,而总磷是绿藻丰度的主要影响因子。控制入库河流营养盐的输入是防控于桥水库水华的有效措施。

Yuqiao Reservoir,a large diversion and storage reservoir for the Luanhe-Tianjin Water Diversion Project,supports industrial,agricultural and urban domestic water usage in Tianjin. In recent years,the eutrophication of Yuqiao Reservoir has become increasingly serious. In May,July,August,September and November of2012,we investigated the composition and distribution of the phytoplankton community and the associated environmental factors at five sites in Yuqiao Reservoir,aiming to understand the relationship between phytoplankton and water quality. The collection,qualitative and quantitative analysis of phytoplankton were carried out according to methods found in the literature. Sixteen water quality parameters were determined including water temperature（ T）,suspended solids（ SS）,fluoride（ F-）,p H,DO,SD,CODMn,CODCr,BOD5,NO2-N,NO3-N,NH3-N,TN,TP,SO2-4and Chl-a. A water quality index,biological indexes and comprehensive nutritional status index（ TLI（ ∑）） were used to evaluate the trophic status in Yuqiao reservoir and the relationship between phytoplankton and water quality was analyzed by redundancy analysis（ RDA）. A total 123 phytoplankton species from 7 phyla were identified,with primary dominance by Chlorophyta（ 64 species） with 52. 0% of the total species. Among them,Microcystis aeruginosa,Microcystis flos-aquae in Cyanophyta and Chlamydomonas sp.,Pediastrum simplex in Chlorophyta were the dominant species. The abundance of phytoplankton in Yuqiao Reservoir ranged from 369. 75× 10^4 cells / L to 4 636. 64 × 10^4 cells / L,with the average value of 1 353. 00 × 10^4 cells / L,and the biomass ranged from 1. 12 mg / L to 13. 58 mg / L,with an average value of 4. 61 mg / L. The phytoplankton community structure exhibited significant seasonal variation,and the variations in species number,abundance and biomass all followed the same trend： summer ﹥ autumn ﹥ spring. The assessment based on the water quality index,biological indexes and comprehensive nutritional status index（ TLI（ ∑）） indicated that the water of Yuqiao Reservoir was mesotrophic to eutrophic and eutrophication was more severe in summer than in autumn or spring,indicating a higher risk of cyanobacteria or green algae blooms in summer. The correlation analysis between phytoplankton community and environmental factors by RDA showed that p H,suspended solids,water temperature,ammonia nitrogen and total phosphorus were the primary factors affecting the phytoplankton community. The abundance of Cyanophyta was highly correlated with p H,while the abundance of Chlorophyta was affected primarily by the concentration of total phosphorus. As a result,controlling the nutrients of input rivers into Yuqiao Reservoir is the effective way to prevent algal blooms.