Effects of environmental factors on phytoplankton abundance in park water bodies of Shanghai

From October 2006 to September 2007, a monthly monitoring was conducted on the phytoplankton community structure and water parameters in the landscape water bodies of 10 parks in Shanghai. Principal components analysis (PCA) and canonical correspondence analysis (CCA) were applied to analyze the relationships between the phytoplankton community structure and water parameters and to assess the status of city water environment, aimed to provide scientific basis to manage the water quality of park water body. A total of 167 phytoplankton species were identified, belonging to eight phyla. The phytoplankton abundance ranged from 2.16×106 to 7.87×106 cells ·L-1, and the phytoplankton community was dominated by Cyanophyta, Bacillariophyta, and Chlorophyta. Phormidium corium, Ph. fovedarum, Merismopedia tenuissima, Synedra acus, M. glauca, and Cryptomonas erosa were the dominant species. The water temperature, water depth, transperancy, total nitrogen, NH4+-N, NO3--N, NO2--N, total phosphorus, soluble reactive phosphorus, and CODMn varied in the range of 7.9-29 ℃, 0.79-1.05 m, 0.5-0.70 m, 0.896-3.9 mg·L-1, 0.224-1.979 mg·L-1, 0.126-0.346 mg·L-1, 0.015-0.140 mg·L-1, 0.063-0.372 mg·L-1, 0.007-0.194 mg·L-1, and 5.418-10.685 mg·L-1, respectively. PCA analysis showed that water temperature and transparency were the main physical factors, and water nitrogen, phosphorus, and CODMn were the main chemical factors affecting the phytoplankton abundance in the water bodies. CCA analysis indicated that water total nitrogen, total phosphorus, transparency, and water temperature were the main factors driving the seasonal dynamics of the phytoplankton abundance and community structure.