Study on ecological environment in Bohai Bay I.species composition and abundance of phytoplankton

Based on the survey data of phytoplankton on 15,Jul.2003,4,Nov.2003,29,Feb.2004 and 25,May.2004 in the Bohai Bay,the species composition,cells abundance,seasonal variation and dominate species of phytoplankton were discussed.The results showed that the main phytoplankton community was diatoms and dinoflagellates,and also small amount of golden-brown algae and blue-green algae in the Bohai Bay.The highest peak of cells abundance appeared in the spring,afterwards gradually decreased,and the lowest peak in winter.The seasonal variation of the phytoplankton was a simple period type in the Bohai Bay.Compared with the history datum,there are different degree changes in cells abundance,seasonal variation and the dominate species composition.