The Phytoplankton Community Structure And Its Relationship With Watur Quality Factors In Yuqiao Reservoir

Yuqiao Reservoir is the only drinking water sources in Tianjin, it carries out water security duties to Tianjin. In recent years, there is a serious blooms in summer due to the pollution of upstream runoff and the surrounding environment, by the relevant departments, and the relevant departments attach great importance to it. To understand the relationship between phytoplankton community characteristics and its water quality factors in Yuqiao Reservoir, The phytoplankton and water quality were continuously monitored during2012-2013spring, summer and autumn. The water quality was evaluated by using diversity and trophic state index. Using the correlation analysis between phytoplankton and water quality factors to investigate the master factor of changes in algae, and then provide a scientific basis for the water source protection planning at Yuqiao reservoir.114kinds of phytoplankton were identified during2012in Yuqiao Reservoir, and the type of community composition was Chlorophyta-Bacillariophyceae. Chlorophyta were the most with62species, followed by Bacillariophyceae with19species,12species of cyanobacteria,13species of Euglenophyta,4specie of Dinophyta,3speciees of Cryptophyta,1species of Xanthophyceae.111kinds of phytoplankton were identified during2013in Yuqiao Reservoir, and the type of community composition were Chlorophyta-Bacillariophyceae. Chlorophyta were the most with55species, followed by Bacillariophyceae with26species,14species of cyanobacteria,7species of Euglenophyta,4specie of Dinophyta,3specie of Cryptophyta, and2species of Chrysophyta.The seasonal variation of Shannon-Weaver index H1was spring (3.22)> autumn (3.17)> summer (2.51) during2012, the seasonal variation of richness index d was spring (2.14)> summer (2.12)> autumn (1.84), the seasonal variation of index J was spring (0.65)=autumn (0".65)> summer (0.48). According to the evaluation criteria, the evaluation results of H’to water quality in spring and autumn were non-polluting, but the summer was3-middle pollution; The evaluation results of the richness d in three seasons to water quality were all middle pollution; The evaluation results of the evenness index J in spring and autumn were non-polluting, while the summer evaluation result was pollution. The seasonal variation of Shannon-Weaver index H1was summer (3.87)=autumn (3.87)> spring (3.00) during2013, the seasonal variation of richness index d was summer (2.38)> autumn (2.27)> spring (2.27), the seasonal variation of index J was the summer (0.75)=autumn (0.75)> spring (0.61). According to the evaluation criteria, the evaluation results of H’to water quality for the three seasons were non-polluting, the evaluation results of the richness d were all middle pollution, and the evaluation results of evenness index J were all non-polluting.The correlation analysis between phytoplankton and environmental factors showed that, chl-a was significantly negatively correlated with SD in spring,2013. In summer, chl-a was significantly negative correlation with SD and nitrate nitrogen, and it was significantly positively correlated with temperature and phosphate, chl-a and was significantly negatively correlated with nitrate nitrogen in autumn. Comprehensive studies had shown that temperature is the main driving force of algae growth in summer (August2013), low SD in the spring and summer hampered algae reproduction, especially in summer. Consistent with the results of previous studies, The Yuqiao Reservoir is phosphorus-control reservoir.