Study On Community Characteristics Of Phytoplankton And Relationship With Environmental Factors In The Haihe River

The Haihe River was the typically sustained river in the north of China, and its flow velocity was very slowly. After the point source and non-point source pollution along the way, the river eutrophication was very serious. Every summer, the degree and size of algal blooms is rising. To study the structure of phytoplankton community and the relationship with environmental factors in Haihe River, an investigation was conducted on the structure of phytoplankton community, meteorology and the quality of water from May to October in the Haihe River. It is hoped that the result data is helpful for the construction of the early warning model of Algal Bloom in Haihe River.(1)According to the investigation and analysis, Jinhe River and Haihe River (Liulin) is mild eutrophication in spring and autumn, severe eutrophication in summer. The dominant species of phytoplankton was Chlorophyta-Cyanophyta-Bacillariophyta.(2)The total nitrogen average concentration of Jinhe River was 7.404mg/L in summer, and the total nitrogen average concentration were 2.576mg/L and 1.377mg/L in spring and autumn, separately. The total nitrogen average concentration of Haihe River(Liulin) was 6.823mg/L in summer, and were 2.043mg/L and 1.104mg/L in spring and autumn, separately. The total phosphorus average concentration of Jinhe River was 0.780mg/L in summer, and were 0.083mg/L and 0.125mg/L in spring and autumn, separately. The total phosphorus average concentration of Haihe River(Liulin) was 0.469mg/L in summer, and were 0.282mg/L and 0.263mg/L in spring and autumn, separately. Integrating a variety of indexes of water quality of Jinhe River and the Haihe River, the water quality in summer was worst, the water quality of the river is better in spring and autumn than summer. At the same time, the river water quality is also very significant circadian variation in summer. During the day, with the increase of light intensity and photosynthetic active radiation, the total nitrogen and phosphorus concentration was the highest at 12:00, at this time, the water quality was the worst in the whole day.(3)The abundance of phytoplankton ranged from 1.76×10~6 to 2.007 × 10~9ind./L. The main dominant species were Scenedesmus quadricauda, Microcystis aeruginosa and Cyclotella meneghiniana. The variation tendency of Shannon-Wiener diversity index and Pielou evenness index was same, with the index in spring and autumn higher than summer. The succession of phytoplankton community was Chlorophyta-Cyanophyta-Bacillariophy ta.(4) PCA indicated that eutrophication level, urban non-point source pollution and the concentration of ions were the first three environmental factors in the Haihe River. CCA indicated that total nitrogen, ammonia nitrogen, temperature and relative humidity could be the main environmental factors which influenced the community structure, and there were strong correlationship between Microcystis aeruginosa and temperature, total nitrogen, total phosphorus, and it was blooming rapidly in summer, part of Chlorophyta and Bacillariophyta were related to nitrate nitrogen.