Spatiotemporal Variations Of Suspended Particulate Material In The Yellow Sea And East China Sea Based On The LISST-100X Field Surveys

The concentration and particle size of suspended particulate material(SPM)are important environmental parameters and are widely used to calculate the sedimentation velocity and flux of particle matter in continental shelf waters.Identifying SPM characteristics through in situ observations can be beneficial in accurately reproducing coastal by using remote sensing and help understanding local sediment dynamics.We analyzed the characteristics of the spatio-temporal distribution of SPM based on SPM,hydrographic,and chlorophyll-a data.First of all,we described the characteristics of the horizontal and vertical distributions of SPM in Yellow Sea and East China Sea(YSECS)in four seasons.Secondly,the YSECS(all stations)were divided into 1)the western region of the Yellow Sea,2)the central region of the Yellow Sea(CYS),3)the off Subei shoal and Changjiang bank,and 4)the middle shelf of the East China Sea(ECS)for analyzing SPM concentration.In addition,we also calculated the ranges of diurnal variation of the vertical distribution of particle concentration.Finally,we discussed the relationship between SPM characteristics and environmental factors.In survey area,the bottom SPM concentrations were higher than those at the surface in four seasons.Among the four seasons,the highest surface concentrations were observed in spring.The high SPM surface concentrations were observed located on Changjiang bank in four seasons;furthermore,the distribution ranges of high concentration showed seasonal variations.The distribution of the particle concentration was similar as the four seasons in the bottom.The high concentrations were observed in the bottom over the Changjiang bank because of the high energetic environment in bank induces strong sediment resuspension.The large SPMs were primarily dominated by mesozooplankton in the surface in spring and summer,while the small SPMs were primarily dominated in autumn and winter and were composed mainly of inorganic particulate matter located on Changjiang bank.The small SPMs were dominated by inorganic particles during the four seasons in the bottom.The highest SPM concentration and large particle concentrations were observed in the pycnocline in the CYS and the middle shelf of the ECS.The highest SPM subsurface concentration was primarily influenced by large particles,which were primarily dominated by mesozooplankton in the same layer.High concentration in the bottom upward diffusion was influenced by the changes of subsurface stratification.In spring,the high SPM concentration was influenced by the phytoplankton bloom in well-mixed upper waters,while high SPM concentration in mid-bottom waters was influenced by the high energetic environment induces strong sediment resuspension.In summer,a double pycnocline exists in the subsurface,high SPM concentration was due to the high biomass of phytoplankton above the stratification at night.The high SPM concentration was primarily influenced by large particles,which were primarily dominated by mesozooplankton in the middle layers.The phenomenon of vertical migration of mesozooplankton was observed in the subsurface in the middle shelf of the ECS.