The Impact Of Hamful Algae Blooms On The Fratures Of Nutrient In The Hight Freuqent Hamful Algae Blooms OCcurrence Areas In East China Sea

East China Sea is the hightest frequency Hamful Algae Blooms occurrence areas in China. Thought the investigation of Hamful Algae Blooms Occurrence Areas, the distribution of nutrient has been mastered. The function of nutrient structure on succession of phytoplankton predominant species has been knowen. But the reportes about the absorption and transformation of nutrients in the survey were less. Beginning with the comparison of changes in the nutrient of 2010, preliminary masters the impact of phytoplankton on nutrient; and then, compares the difference between the catual value and the the theoretical value, and compares the proportion and concentration of different forms of nutrients during the red tide, with the chl-a date, discusses the uptake and transformation of nutrient by phytoplankton; finally, a dynamic model was established, using the mode calculates the nutrients uptake which the phytoplankton absorbed during the red tides outbreak. Main conclusions were summarized as follows:(1) The analysis of environmental factors in 2010, shows that: From April to May,From April to May, the temperature of the Hamful Algae Blooms Occurrence Areas are raduced and salinity changes little, the temperature is increased, and the salinity is changed little, isoline indicate a tendency of decline from coast to offshore; the concentration of DO is decreased, at the surface and middle, the concentration of DO in the north is higher than the south, at the bottom the congcentration become lower from coast to offshore; pH has increased.(2) Influenced by terrestrial, the distribution of isolines in 2010, which expressed the concentration of nutrient parallels with coast line and it reduced from coast to offshore. Red tide breakes out at May, the concentration of DIN and PO₄-P are decreased rapidly, while the concentration of SiO₃-Si is increased. In April, isoline of nutrient in the north, the central, the south section indicate a tendency of decline from coastal surface to distal bottom; isoline of DIN and SiO₃-Si in May are the same as April, isoline of PO₄-P indicate a tendency of increase from surface to bottom, concentration of DIN and PO₄-P are decreased in May, while they are increased in July. By comparation of the nutrient from the north to the south, the influence degree of terrestrial input is weake from north to south at the surface, middle. The influence of Taiwan Warm Current is weake from south to north at the bottom.(3) The catual values of DIN and PO₄-P are deviate from the theoretical value which was calculated from the theory of salinity and nutrient relationships; the phytoplankton absorption of nutrients is obvious.(4) In April, the main componentes of N are NO₃-N and DON, the proportion of PN is lower. In May, the proportion of NO₃-N is declined in each layer, while the proportions of DON,PN are increased. In July, the proportion of NO₃-N is increased; the percengtage closes to April levels. The proportion of DON and PN is declined. In April, the main componentes of P are PO₄-P and PP, the relationship of the proportion of different forms of P is PO₄-Pï¹¥PPï¹¥DOP. In May, the proportion of PO₄-P is declined, while the proportions of DOP and PN are increased. In July, the proportion of PO₄-P is increased at the surface and middle, the proportion of DOP is declined, and the proportion of PP is changed little. At the bottom, the proportion of DOP is increased, while the proportion of PO₄-P and PP are down. At the surface and middle which influenced by pHytoplankton , accounted for the largest proportion of N is"NO₃-Nâ†'DON,PNâ†'NO₃-N"from April to July. The argest proportion of P is"PO₄-Pâ†'DOP,PPâ†'PO₄-P".(5) The componentes of all forms of nutrient is changed violently at the surface and middle which contains higher chl_a, the components change small. The nutrient change from inorganic form to organic form and particle shape during the explosion of red tide. During the extinction of red tide, the organic and particlate nutrient changes into inorganic.(6) A dynamic model was established and it can well simulate the process of Red Tide in 2010. Using the mode calculates the nutrients uptake which the phytoplankton absorbed during the red tides outbreak, the results show that the phytoplankton absorbe huge amount of nutrient. Phytoplankton plays an important role in nutrient regeneration.