Temporal and spatial distribution of nutrient in coastal area of East China Sea in Spring 2006

The nutrient(DIN,PO4-P,SiO3-Si,NH4-N) concentrations in the coastal area of East China Sea were measured in spring,2006,and the relationship between the spatial distribution of the nutrients and the red tide occurrence in the studied area was analyzed.The results showed that comparing with 1st class seawater quality of the national standard,the concentrations of dissolved inorganic nitrogen(DIN) and PO4-P were 54% and 34% higher,respectively.Specially,it was the disadvantage of eutrophication in Hangzhou Bay.Furthermore,the concentrations of nutrients in shore were much higher than those offshore,and the isolines nearly are paralleled with the coastline,meaning that nutrient distributions were mainly influenced by the terrestrial discharges.The variety of chemical factors during occurrence of the red tide is discussed.