ANALYSIS OF NUTRIENT DISTRIBUTIONS AND POTENTIAL EUTROPHICATION IN SEAWATER OF THE JIAOZHOU BAY

Based on 3 cruises of observed nutrient data in the Jiaozhou Bay in May,August,and October of 2009,the distribution characteristics and variabilities of nutrients in seawater of the sea area are analyzed,and the potential eutrophication conditions of water quality are assessed.It is showed from the analysis results that the annual mean concentration of dissolved inorganic nitrogen(DIN),active phosphate and active silicate were 0.335,0.028,and 0.725 mg/L.The concentration of nutrient in August was higher than that in May and October.The spatial distribution of nutrients appeared a downward trend from two high concentration areas including eastern estuary and northern breeding area to low concentration areas including bay center and the mouth.The annual mean rations of DIN∶ P,Si∶ DIN and Si∶ P were 53.9,2.03,and 57.7,respectively,and phosphate was the limiting factor,the whole water was in the middle-phosphorus-limiting to phosphorus-limiting potential eutrophication,Loushan Estuary and Licun Estuary were in moderate eutrophication to rich eutrophication,the massive importation of phosphorus outside may occur red tide.