Distribution Of Suspended Matters And Their Influence Factors In The Shelf Area Of The East China Sea In Summer

Based on data of hydrologic and suspended matters which were obtained in June and July of 2012, we have have discussed the distribution of suspended matters in the shelf of the East China Sea in summer, and we also have analyzed its influence factors caused by water mass, coastal upwelling off Zhejiang(CUZ), thermocline and the submarine sedimentary environment. The major conclusions are as follows.The value of total suspended matters(TSM), volume concentration of suspended matters(VC), mean diameter of suspended matters(DM) and chlorophyll(Chl) in the upper layer(surface~30m) is much higher in the nearshore area than in the offshore area, but the value of effective density of suspended matters(△ρ) is higher in the offshore area than in the nearshore area. With the depth increased, the distribution of TSM doesn’t change a lot, but VC, DM and Chl in the nearshore area decreased gradually, and △ρ in the nearshore area increased gradually. The value of TSM and VC in the bottom layer is higher than the value in the upper layer, and the value in the nearshore is higher than the value in the offshore area; the DM is higher between the nearshore and offshore, which shows a belt parallel to the coast; the value of Chl in the bottom layer is lower than the value in the upper layer, and the value in the nearshore is higher than the value in the offshore area;the value of △ρ in the nearshore area is lower than the value in the offshore area, and the vale of nearshore area in the bottom layer is higher than the upper layer, the value of offshore area in the bottom layer is lower than the value in the upper layer.The vetical distribution of VC and Chl is well related. The value of VC and Chl is higher in the area of halinecline in the nearshore, the area of thermocline in the offshore and the area which the upwelling influenced. The value of VC and Chl is lower in the upper offshore area, and their contour line are unanimous.The distribution of suspended matters in the study area is chiefly affected by the land diluted water(LDW), the coastal upwelling off Zhejiang(CUZ),the thermocline and the submarine sedimentary environment, among which the main factor is the superimposed effect from LDW, CUZ and the thermocline. The rich nutrients carrid by LDW and CUZ can greatly promote the reproduction of phytoplanton; the thermocline can make the water steable in the vetical direction, which can also promote the growth and reproduction of phytoplantion, the massive phytoplantion can result in the higher value of VC, DM, Chl and the lower value of the △ρ. The resuspension caused by the waves and tidal currents can lead to the value of TSM and VC in the bottom water higher than the value in its upper water, and the value of Chl in bottom water lower than the value in its upper water, and the abundant resuspend matter in the bottom water can make the suspended matter in the bottom water flocculate, which can make the DM increase and the △ρ decrease in some area.