The Research Of Community Structure Of Phytoplankton In Shanghai Qingcaosha Reservoir And Arounding Waters

Qingcaosha Reservoir is the largest drinking water reservoir in Shanghai,in Changxing Island,Chongming.The reservoir is concerned with the use of water by thousands of people,so the safety issue is very important.Phytoplankton is an important member of water environment,to study it can reflect the quality of water.In this sampling survey between January 2016 and December monthly on phytoplankton in Qingcaosha Reservoir,we mainly analyzed the species composition of Qingcaosha Reservoir,and the change trend of biomass.The comparative study of the diversity index,the composition of dominant species,and the situation of the Yangtze River and the Zhongyangsha water outside the reservoir.The main results are as follows:1.Total of identified were 181 species and varieties of phytoplankton in Qingcaosha Reservoir in 2016,belonging to 7 phyla.Among them,26 species of Cyanophyta,3 species of Pyrrophyta,2 species of Chrysophyta,3 species of Xanthophyta,66 species of Bacillariophyta,11 species of Euglenophyta,and 70 species of Chlorophyta.Chlorophyta algae were the most,accounting for the total number of species 38.67%,Bacillariophyta respectively,were accounted 36.46% and Chrysophyta were the least,accounting 1.10%.The species number of in summer were the most,135,followed by winter,there are 123 kinds.The least number of species in the autumn season.Bacillariophyta dominate in the winter,and Chlorophyta is dominant in the other three seasons.There were 6 dominant species in the community structure of phytoplankton,which belonged to 4 phyla.The top four dominance of phytoplankton: Cyclotella sp.,Tribonema sp.,Tribonema sp.and Melosira ambigua.2.The average annual density of phytoplankton were(276.06±379.40)×10~4 cell/L in 2016,the density of phytoplankton showed a typical doublet pattern in the whole year.The annual variation of phytoplankton density showed higher in spring and summer,lower in autumn and winter.The change in average annual density on the transition region of the highest,second lowest lake district,river area site.In 2016,the average annual biomass of phytoplankton in the reservoir was(0.7554±0.9844)mg/L,with the overall trend in biomass and biological density consistent.The change in average annual biomass on the upper reaches of the highest,second lowest downstream,upstream site.The highest biomass in the middle reaches of the site in spatial distribution.3.The average value of Shannon-Wiener diversity of phytoplankton in inside and outside of bio-manipulation pen and demonstration project area were(1.72±0.50),(0.54±0.15)and(1.88±0.53).Among them,H ’and J values in the months between the change trend is consistent.The seasonal variation of these 3 indices showed very significant difference in 2016.4.RDA analysis of the relationship between dominant species of phytoplankton and environment,the results show that most of the species has a positive correlationwithconductivity,and has a negative correlation with depth and transparency.5.Total of identified were 140 species and varieties of phytoplankton in Zhongyangsha Water area,belonging to 7 phyla.Total of identified were 59 species and varieties of phytoplankton in Yangtze River,belonging to 5 phyla.The average annual density of phytoplankton were(678.08 ±693.79)×10~4 cell/L in Zhongyangsha River in 2016.The average annual density of phytoplankton were(78.96±138.40)×10~4 cell/Lin Yangtze River in 2016.The density of the Qingcaosha reservoir is higher than that of the Yangtze River,which is lower than that of the Zhongyangsha Water area.