ABSTRACT
ABSTRACT: As a storage reservoir, Daning reservoir is an important part of South-North Water Diversion Supporting Projects in Beijing. It’s necessary and meaningful to carry out field monitoring to find out water quality and aquatic ecosystem health status. Three times of field monitoring were carried on in April, June and August 2013, with three monitoring sites set from south to north of the reservoir. 7 classes and 64 species of algae were found during the monitoring. The highest number of species and density was Chlorophyta and Cyanophyta respectively. The dominant species was Synedraacusvar in April and Microcystis from June to August. Single factor evaluation method, comprehensive trophic state index (TLI index) and integrated ecology health index (EHI) were used to evaluate the aquatic ecosystem status of reservoir. The comprehensive evaluation results showed that: 1) the water quality was on grad II, the nutrition status was mesotrophic, and the EHI value was from 0.41 to 0.63 on the whole reservoir. 2) the water quality and ecosystem health reduced gradually from April to August, while there didn’t exist much difference of aquatic ecosystem status in space. Although the overall water quality was good, the concentration of TN was relatively high. Eutrophication trend still existed, and the problem of potamogeton crispus soaring during the period from June to August must be concerned.
