The Diversity Of Phytoplankton In Haihe River Basin

Phytoplankton is an important biotic component of aquatic ecosystem. This thesis is based on the investigation of the Phytoplankton community at 197 sampling sites in Haihe river basin during July to October,2009. The species composition, the dominant species, density and biomass of Phytoplankton were analysized. The water quality of Haihe river basin was evaluated on the basis of Phytoplankton community. The main results are as follows:1.The results revealed that 430 species of phytoplankton belonging to 8 phyla and 119 genera existed in Haihe river basin.149 species belonging to 51 genera of Chlorophyta 34.65%,148 species belonging to 30 genera of Bacillariophyta 34.42%,63 species belonging to 19 genera of Cyanophyta 14.65%,48 species belonging to 6 genera of Euglenophyta 11.16%,7 species belonging to 2 genera of Cryptophyta 1.63%,5 species belonging to 4 genera of Pyrrophyta 1.16%,5 species belonging to 3 genera of Chrysophyta 1.16%,5 species belonging to 4 genera of Xanthophyta 1.16%.2.Dominant species belonging to Cyanophyta,Chlorophyta and Bacillariophyta, are as follows:Dactylococcopsis,Oscillatoria agardhii,Spirulina maxima,Chroococcus minutus in Cyanophyta; Chlorococcum infusionum,Scenedesmus guadricauda,Chlorella in Chlorophyta; Cyclotella meneghiniana,Navicula,Nitzschia in Bacillariophyta.3.The mean density and biomass of phytoplankton in Haihe river basin were 11.24×106 ind./L and 3.80 mg/L. The density and biomass of Chlorophyta were 4.65×106 ind./L and 1.22 mg/L, accounting for 41.37% of total density and 32.11% of total biomass, respectively; The density and biomass of Cyanophyta were 2.87×106 ind./L and 0.47 mg/L, accounting for 25.53% of total density and 12.37% of total biomass, respectively; The density and biomass of Bacillariophyta were 2.76×106 ind./L and 0.94 mg/L, accounting for 24.56% of total density and 24.74% of total biomass, respectively; The density and biomass of Euglenophyta were 0.59×106 ind./L and 0.68 mg/L, accounting for 5.25% of total density and 17.89% of total biomass, respectively; The density and biomass of Cryptophyta were 0.33×106 ind./L and 0.39 mg/L, accounting for 2.94% of total density and 10.26% of total biomass, respectively; The density and biomass of Pyrrophyta were 0.02×106 ind./L and 0.09 mg/L, accounting for 0.18% of total density and 2.37% of total biomass, respectively; The density and biomass of Chrysophyta were 0.01×10 ind./L and 0.01 mg/L, the percentage of total density and total biomass are negligible, both; The density and biomass of Xanthophyta were 0.30×104ind./L and 0.50×10-2mg/L, the percentage of total density and total biomass are negligible, both.4. The Shannon-Weaver index, Margalef index and Pielou index varied among 0.44～4.83,1.73～10.69 and 0.09～0.95 in Haihe River basin, in addition, the mean are 3.34,6.30 and 0.64, respectively.5. The Haihe river basin was classified as eutrophic water when the indicator species were adopted to assess the eutrophication level, but was categorized into mesotrophic water when biomass index was used. Based on the results of evaluation of Shannon-Weaver index, Margalef index and Pielou index, the Haihe river basin belonged to middle pollution. Some differences were among different evaluations, therefore, we should consider all the evaluations to balance the differences. In conclusion water quality belong to mesotrophic, but had the potential to turn to eutrophication. So we should pay attention to protecting the water quality and enhance the management of the Haihe river basin.