| The concentration and biogeochemical composition of metal elements in sediment is of immense importance in the marine biogeochemical cycles of trace elements and global change. It has become the important themes in the global scientific programs, such as LOICZ (Land-Ocean Interactions in the Coastal Zone) and GEOTRACES (An international study of the Marine Biogeochemical Cycles of Trace Elements and Their Isotopes). The concentrations and variations of metal elements in the core sediments are valuable information to discriminate sediment source and to reconstruct paleoenviroment.In this dissertation, surface sediments near the Changjiang Estuary and core sediments collected by multi-corer and gravity corer from typical stations in the Yellow Sea and East China Sea Shelf are digested and the concentrations of metals (Al, Ti, Fe, Mn, Ba, Cu, Zn) are analyzed. The impact of human activity on the coastal and shelf environment is studied. For those samples with special ratios of Al/Ti in the sediment cores, sequential extractions are performed to determine the speciation (carbonate, oxide, organic, opal, residual fractions) of Al and Ti in carbonate, oxide, organic, opal and residual fractions. The behavior of"Excess Al"in the coastal area is studied, including the distributions and exist fractions, which set the foundation for further research on the possibility of reconstruction of pelo-productivity by Al/Ti ratio in the marginal sea.The concentrations of metal elements are obviously higher in the coastal area and lower in the Shelf zone. Surface sediment from E5 station near Zhejiang province has the highest metal contents, while the lowest concentration appears in the middle of the East China Sea Shelf. The contents of metal elements from station E2 which located in the middle of the Yellow Sea are different from other stations with high concentration of Zn and low concentration of Mn and Cu. The contents of metal elements in the core sediments from P4 station at the edge of the East China Sea Shelf are high in Cu, Zn and low in Al, Ti, which probably is caused by the high biogenic impact.The surface sediment in the middle East China Sea Shelf comes mainly from the terrestrial transported by Changjiang. Along the coast, sediment has clearly shown the evidence of Zn pollution, while Cu pollution is not so obvious in the same area, except for one or two stations. Based on our results, heavy metal pollution has not been seen in the center of the Yellow Sea and the East China Sea Shelf yet. Core sample from Zhejiang coastal area shows great increase in contents of Zn and Cu since 50 cm to the surface as a result of human perturbulation.The source of the mud area in the middle Yellow Sea has always been complicated for researchers. The sediment, there, is of high concentration of Zn and lack of Cu and Mn, compared to the Huanghe and Changjiang sediments, and show the possibility of other important source besides those two rivers. The sediment in the central East China Sea has similar metal concentrations with the surface sediment from Changjiang.In this essay,"Excess Al"signal is found in the Yellow Sea and East China Sea Shelf. As to those layers with high Al/Ti ratios, sequential extraction is carried out. None residual Al mainly exists in Fe-Mn Oxide fraction and Ti in Organic and Opal fractions. For a single core, the changes of Al/Ti ratios correspond well with the concentration of Al in Opal, Oxide and Organic fractions. Al/Ti ratios and the concentrations of BSi show pretty good coefficient, which means on a certain extent, excess Al concentration still can show biogenic matters flux on the shelf area. However, as to different area on the shelf, this relationship is not always stable. Since shelf receives large amount of terrestrial material, the biogeochemical characteristics of Al/Ti ratio of the sediment is far complicated than that of the open ocean. Further study is still needed to minimize the terrestrial impact in the marginal seas to use Al/Ti ratio as a proxy to reconstruct the paleo-productivity.
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