Abstract:

The composition and quantity of phytoplankton were investigated in the Ancient Canal in Zhenjiang City,and the effect of environmental factors on the composition and quantity of phytoplankton were simultaneously discussed to find out the phytoplankton distribution of the urban river connected with the Yangtze River and to establish effective restoration plan.Results showed that there were 38 species of phytoplankton belonging to 6 phyla,in which Chlorophyta,Cyanophyta and Bacillariophyta were familiar phyla.In general,the biomass and density of phytoplankton were spring＞autumn＞summer＞winter.Compared with the reference site on riverhead,the biomass and density of phytoplankton increased severely along the river in spring and autumn,and the composition of algae was gradually changed from the predominant Bacillariophyta phylum to the predominant phyla Chlorophyta and Cyanophyta,but these change trends were not evident in summer and winter.The growth of phytoplankton in the river was influenced by various factors including the hydraulic condition,the nutrient level,the water temperature and the suspended sediments in water.Among these,the change of hydraulic condition caused by the impounding was primary.