The Primary Study Of Distribution Of Chlorophyll A, Dissolved Organic Carbon In Yellow-East China Sea And The Carbon Fixed Production Of Phytoplankton

With the development of economy and the increasing influence by human activities, the quality of marine environment especially in Yellow- East China Sea tends more serious than ever before. This induced several serious problems in marine environment and ecosystem such as the worsing of sea water, unbalance of marine ecosystem and high frequence of HAB. Two cruises were carried out in Yellow- East China Sea during summer (28th June～15th July)and winter (22th Junuary～13th February). In this thesis, the field data as well as hydrographical, chemical factors were ananlyzed for the purpose of the study on the distribution of chlorophyll a, dissolved organic carbon(DOC), and the effect of the carbon fixed production of phytoplankton (CFP) to the distribution of DOC. The main conclusions were summarized as followings:The concentration of chlorophyll a changed great (0.01-13.81μg/L) in summer. In the horizontal distribution, the value of chlorophyll a was decreased from the shore to the open sea in summer. Affected by Chang Jiang River and the upwelling water, the area of high values was near to the estuary of Chang Jiang and the alongshore of Minzhe, the area of low values emerged in the Kurosio water. And the sectional distribution of chlorophyll a in summer displayed layer characteristic.The value of chlorophyll a in winter was low in most of the survey area, and the range of it was small(0.04-2.56μg/L), the area of high values centralized at south of 28°N. The sectional distribution of chlorophyll a changed little from surface to the bottom in each section in winter.The main factors affect the distribution of chlorophyll a in Yellow-East China Sea was nutrients, insolation, temperature and so on. The factors made different effection in different seasons, different sections. Nutrient was the main factor that affected the distribution of chlorophyll a on the surface of section3 and the slope area of section S07, S08, S10. In the alongshore of section S04 and S05, the main factor was insolation. Temperature was the main factor in winter.The concentration of DOC was generally high in north and low in south of the survey area in summer. The high concentration areas in different sections were centralized at 50m up to the shallow water, which showed the layer characteristic.In winter, the concentration of DOC was equal in the horizontal ditribution of most survey area, only a slightly higher in the south area. As to the sectional distribution of DOC, the high value areas most emerged in the alongshore. For the effect of vertical mixing, the concentration of DOC changed little as the increasing of depth in winter. The concentration of DOC was higher in summer than in winter especially in the shallow area, this difference minshed as the increasing of the depth.The distribution of it was desceased from the shore to the open sea in summer, was generally high in the south area and low in the north area in winter. The value of CFP in coastle water of East China Sea was higher than other China Sea in summer, and slightly lower than the whole East China Sea, which was attributed to the location of East China Sea and the characteristic of flows.The similar areas of the distribution of chlorophyll a and DOC only appeared at the open sea, for it was far from the alongshore, the waters kept stable and the main source of DOC in it was CFP. Seen from all the sections, when the value of chlorophyll a was high, the DOC was relative high too. But influenced by the effect of hydrodynamic in the survey area, the distribution of them was different.