| Xiangjiang River is the mother river of Hunan and also one of the major tributaries of the Yangtze River. Reservoir of "Changsha-Zhuzhou-Xiangtan" region is located in 2 of the most developed 9 levels, which is between Hangdian Dayuandu dam and Changsha Wangcheng Changsha integrated hub in Cai jia zhou territory in Xiangjiang River, covering a total length of 132 km from south to north. From June 2014 to March 2015, four rounds of sampling survey has been taken by crossing the spring, summer, autumn, winter, and 8 sampling points were set respectively on the middle and lower reaches in Zhuzhou region Xiangtan and Changsha region segment set. This paper uses statistical methods such as biological species and season from "Changsha-Zhuzhou-Xiangtan" region of Xiangjiang River phytoplankton distribution, density and biomass research, biological diversity index, and uses SPSS correlation analysis to examine the impact of the major environmental factors on phytoplankton. The main findings are as follows:1. The annual survey identified belong to 94 species 181 Genera 8 Phylums, while the most is green algae which included 64 species,50 species diatoms followed, Euglenophyta was 27 species, Cyanophyta was 18 species, yellow algae was 6 species, Chrysophyta was six species, Dinoflagellates was 6 species, and Cryptophyta was 4 species. Seasonal variation of phytoplankton species from Changsha to clear the reservoir area was indicated by the change in the number of phytoplankton species, which appear as autumn> summer> spring> winter. Among them,24 common species were found in green algae and diatoms main door,13 dominant species, mostly diatoms door. Annual linear variation dominant species of algae (M.varians) and Chlorella vulgaris (C.vulgris).2. From Changsha to the Reservoir, phytoplankton abundance and biomass changed significantly throughout the year, the gross annual seasonal abundance at 11.22× 104cells/L-26.75×104cells/L fluctuated between, highest in autumn, followed by summer and spring, lowest in winter. Gross annual seasonal fluctuations in biomass 0.0447mg/ L-2.0918mg/L, trends for the autumn> winter> summer> spring.3. During the investigation, in the index from "Changsha-Zhuzhou-Xiangtan"region of Xiangjiang River phytoplankton biodiversity, the average seasonal ranged Shannon-Wiener diversity index H from 2.82 to 4.27, the annual average was 3.84, the highest point appears in the fall, the lowest point was in winter. Margalef richness index D range of seasonal mean change 0.82 to 4.48, the annual average was 2.89, peaking in the fall, the minimum in winter. Pielou index J hook both seasonal range of the average change of 0.71 to 0.84, with an average annual 0.77, highest in winter and lowest in autumn. Each stream segment Shannon-Wiener diversity index H of change in the average range of 4.27-3.21, the annual average of 3.84. Each stream segment Margalef richness index D range of the average change of 2.48-3.33, the annual average was 2.89. Pielou index J hooks are each stream segment average changes range from 0.69 to 0.8, with an average annual 0.77. The diversity index in three streams each segment showed the Xiangtan region> Changsha region> Zhuzhou region.4. For the whole year, in "Changsha-Zhuzhou-Xiangtan" region of Xiangjiang River, phytoplankton species and nitrite were significantly positive correlated, D and pH and transparency was significantly and positively correlated. Observing in different seasons, the number and abundance of species in spring and total nitrogen was significantly positively correlated with transparency was a significant negative correlation; H and chlorophyll a was significantly and positively correlated; D and the dissolved oxygen was significantly and negatively correlated. In summer, H and nitrite was significantly and positively correlated with transparency showing a significant negative correlation. In winter, H and nitrite was significantly and negatively correlated. Autumn phytoplankton abundance and chlorophyll was significantly and positively correlated; H and total nitrogen, total phosphorus, nitrite was significantly and positively correlated.5. Three indices of biodiversity were used to evaluate the water quality of reservoir of "Changsha-Zhuzhou-Xiangtan" region, and the result showed the water quality could be regarded as a-mesosaprobic. There was some differences of water quality among various month and spatial variations. Water quality was autumn> summer> spring> winter in the season, and the stream segment was Xiangtan region> Changsha region> Zhuzhou region. |
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