Effects of chemical ecological adjustment and control experiment on phytoplankton community in the Aoshan Bay

There is a low nutrient level in the Aoshan Bay.In June 1999,the chemical adjustment and control experiment was made in the Aoshan Bay.Following tracts investigation was carried out before the experiment and on the 1st,2nd,4th,5th,6th and 45th day/after the experiment.While the variance of amount of phytoplankton,the replacement of superior species and the species composition of phytoplankton were researched.The results show that the amount of phytoplankton in the Aoshan Bay rises gradually after the experiment.Ceratium macroceros Cleve of pyrophyta was the dominant species before the experiment,its dominant index was 37.7%.Six days after the experiment,its dominant index dropped to 17.6%.Meanwhile the dominant index of Asterionella japanics Cleve rose from 7.1% to 39.2%,it became the first dominant species.Forty-five days after the experiment,the amount of phytoplankton in the Aoshan Bay was 5.15 to 137.32 times more than that in 1997.