Study Of Phytoplankton Specific Composition And Biomass In Miyun Reservoir

Phytoplankton was a kind of tiny plants,which floated life in the water,and it was the primary producers over the waters,was also an important part of water biological resources,the biomass the change of community composition directly affected the health and the primary productivity of water ecosystem.Therefore,investigation of community structure and accurate estimates of biomass about the phytoplankton in water had important ecological significance.Taking Miyun reservoir as the study area in this thesis,the speci es composition and stock of phytoplankton haven been investigated and studied over two years.By constructing 11kinds of criteria cell geometry simulation of 29 kinds of phytoplankton in Miyun reservoir,the difference between measured values and the literature value were studied,and according to the establishment of the regression equation between content of carbon or nitrogen and cell volume of algal cells,the credibility of the method estimatied phytoplankton biomass in Miyun reservoir using of cell volume was proved.Related research results were as follows:1.The phytoplankton in Miyun reservoir was detected 232 species in 2016-2017,of which chlorophyta included most species,accounted for percentage of 44.4 of the total number of species,followed by bacillariophyta.The average density of phytoplankton was 505.97 x 10⁴ ind./L,and the biomass with an average of 2.699 mg/L,standing crop of phytoplankton in 2017 was more than 2016,the phytoplankton community structure in Miyun reservoir belonged to the diatom-green algae.2.According to compare between the measured and literature value of 29 kinds of phytoplankton cell volume,the difference range of which were in 0.005-0.0598×10^-44 mg/cell,of which 13 kinds of algal cells in the measured values were less than the literature value,and 10kinds of algae cell volume had significantly difference between measured values and literature value.According to algal cell volume of literature value subtracting the measured values compared with the measured values,the ratio of 11 kinds of algae were between 0 and 1,and the ratio of 4 kinds of algae were greater than 2.5.By conversion calculation between biomass and volume,there are significant differences between the measured biomass and reference biomass.3.The carbon or nitrogen content of three kinds common green algae cell In Miyun reservoir analysis showed that Scenedesmus quadricauda(C:1.81x10^-4±0.053x10^-4ug·cell^-1N:0.58x10^-4±0.037x10^-4ug·cell^-1)>Scenedesmus obliquus(C:1.77x10^-4±0.021x10^-44 ug·cell^-11 N:0.51x10^-4±0.041x10^-4ug·cell^-1)>Ankistrodesmus acicularis(C:1.55x10^-4±0.036x10^-44 ug·cell^-11 N:0.42x10-4±0.064x10-4 ug·cell-1),and the three species had significant difference.The content of carbon and nitrogen of their cells was positive regression relation,the significant logarithm positive correlation relationship existed between the cell carbon or nitrogen content and single cells of phytoplankton,that can be implemented biomass estimation through the cell volume of phytoplankton.4.according to contrasting the measured values and the conversion value of three kinds of phytoplankton biomass,their biomass were not significant difference,and there were no significant difference between lab-grown sample cell volume and field collection of samples,that suggested reliability of establish regression model between cell volume and carbon or nitrogen content was higher.