Abstract: To compare the structure of phytoplankton community and understand its responses to environmental changes in the bioremediation and non-remediation areas of Hangzhou Bay, ten sites were monthly sampled from July to December 2017. During this period, the average concentration of nutrients in the remediation area was lower than that in the non-remediation area. A total of 103 species belonging to eight phyla were identified, and Bacillariophyta was the most diverse group. A total of 54 and 79 species were identified in the bioremediation and nonremediation areas, respectively. The species shared by the two areas accounted for 29.1% of the total species. In the bioremediation area, the average cell abundance was 1.3×10⁴ cells·L^-1 and Trachelomonassp. was the most dominant species. In the nonremediation area, the average cellabundance was 12.3×10⁴ cells·L^-1 and Cyclotella meneghiniana was the most dominant species. The results of redundancy analysis indicated that silicate concentration and pH was the most important factors affecting the abundance of phytoplankton in the bioremediation and non-remediation areas, respectively.

Key words: Rice field, Ammonia volatilization, Wet deposition