The organic carbon of phytoplanktonwas measured in MeiZhou Bay in the Summer of 1992.POC(B) Content varied in 42.5￣185.0 μg/dm 3,with an average concentrtiom of 77.5 μg/dm 3.The relationship between POC(B) and chlorphyll a content can be expressed as following,POC(B)=62.4 chla.The organic Carbon of phytophankton measured by ATP was hight than that by 14 C tracer method.The growth of phytoplankton was limited by the lack of nitrogen in Meizhon Bay.The supply and cycling of nutrients play an impo...