| The ocean is a large pool of carbon. The biogeochemical processes happened to carbon in the ocean play an important part in controlling the content of CO2 in atmosphere, and Carbon Dioxide which was transferred to the bottom of the sea is in the form of POC, So, researches about POC attract much attention of oceanographers. Marginal Seas take an important role in the ocean carbon cycling because of its smaller area and higher productivity, and also get oceanographers'eyes. This article used the data of two full-scale marine surveys and several sequent pointing researches which were carried out in June to July, 2007 and January to February, 2007 to analyze the content and distribution characteristics of POC and PN, and proved the feasibility of judging the source of particulate matter by the ratio of C/N. Among so many influence factors, the import effect of water mass was emphasized. And at last, vertical flux of particulate organic matter from euphotic zone was calculated by Stokes formula in four representative stations of summer. The main conclusions are as follows:(1) The concentration and horizontal distribution of POC and PN lead to the following conclusions. In the whole, the content of POC and PN is much higher in summer. The highest value appeared nearby the Changjiang estuary both in summer and winter, and the decrease of their contents with the increase of the distance from the shore indicates the huge influence of Changjiang River. In summer, the production of phytoplankton is active and contributes most to the content of POC. The linear coefficient of POC and PN in summer is above 0.9 shows that they probably come from the same sources; and the value is lower in winter, but still exceeds 0.6.(2) The concentration and profile distribution of POC and PN lead to the following conclusions. The content of POC is higher in summer in every surveyed profile, but the PN is complicated. It is the same with POC in the Yellow Sea and reverse in the East Sea. The vertical variation of particulate organic matter is little in coastal area because the water is shallow and well mixed. Affected by different seasonal water masses, the profile distribution of particulate organic matter shows obvious layered phenomenon in offshore area, and it is mostly controlled by biological activities. Using the ratio of C/N to distinguish the source of particulate matter is feasible, but in some special cases it also needs other parameters to support.(3) From the analysis of POC and PN in different area, some conclusions are got. In summer, the vertical distribution of POC and PN in the same water mass is uniform; but in winter, only the stations with deep water in Kuroshio area hold the same rule with summer, because the characters of Kuroshio change little with season in this area. So the stability of water mass plays an important role in the vertical distribution of POC and PN.(4) The calculated results of the sedimentation speed and fluxes in four representative stations show that: Bigger particles make more contribution in the sedimentation.; The sedimentation fluxes of POC and PN follow the same trend, Chanjiang Estuary>Coastal Upwelling> Kuroshio.; The maximum of the fluxes appeared in station FJ07 indicates the significant effect of terrestrial input further; The fluxes of station S0703 and station S1004 are much higher than station S1008, which suggest that coastal upwelling field is a crucial area in the transfer of particulate organic matter to the bottom of the sea; Compared to other sea area, these calculated results are credible to some extend. |
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