Hydrodynamic condition and suspended sediment diffusion in the Yellow Sea and East China Sea

Abstract

Based on monthly averaged current, temperature, and salinity, we analyzed the changes of suspended sediment concentration (SSC) and the relationship with the warm current, coastal current, and cold water mass (CWM) in the East China Seas (ECSs). The result shows that the coastal current and surface diluted water are the route for transporting suspended sediment. The Kuroshio and its derived warm current branches play the important role of the continental shelf circulation system and control the diffusion of suspended sediment. High SSC has been mainly concentrated in coastal current and CWM. Two sedimentary dynamic patterns have been identified. The winter‐half‐year pattern lasts almost 7 months. The coastal currents off the Shandong Peninsula, northern Jiangsu, Zhejiang‐Fujian coast are the main routes for diffusion and deposition of the suspended sediment from the Yellow River and Changjiang River. The summer‐half‐year pattern is characterized by the well‐developed CWM. All CWMs have a unique function to trap suspended sediment under the thermocline due to weakening tidal current and residual current there. These CWMs in the Yellow Sea (YS) and north ECS are connected together. The layer above the thermocline is characterized by diluted water with low salinity, high temperature. Suspended sediment can be transported into the Okinawa Trough and the South Korea coast during this period. A strong eddy always occur nearby the Kuroshio bend at northeast Taiwan, which has promoted the exchange between the ECS shelf and Okinawa Trough, and the development of the shelf edge current and Taiwan warm current (TWC).

Variation in the Current Shear Front and Its Potential Effect on Sediment Transport Over the Inner Shelf of the East China Sea in Winter

“…This CSF is an important hydrodynamic phenomenon within the complicated current system over the inner shelf of the East China Sea (ECS). This CSF has been observed by Zeng et al (), and the water temperature, salinity, and suspended sediment data also have similar front at this area (Bian, Jiang, Quan, et al, ; Dong et al, ; Li et al, ; Liu et al, ); however, direct research on the characteristics and the variation mechanism of the CSFs in this region are very scarce. In fact, although the CSF is not a transient or local dynamic process spatiotemporally, its dynamic effects on sediment transport have been universally ignored.…”

Deconvolving the Fate of Carbon in Coastal Sediments

“…River-dominated areas, such as the Huanghe (region 1) and Changjiang (region 4) impact zones, echo the movement and deposition of sediments supplied by the rivers as described by Saito et al (2001), Liu et al (2006Liu et al ( , 2007 and Niino and Emery (1961). Furthermore, the fine-grained muds of the shelf as described by Li et al (2016) and Niino and Emery (1961) match well with the Mid ECS-YS shelf (region 2). Additionally, the Inner ECS-YS shelf matches the areas where higher sediment erosion rates have been observed (Zhu & Chang, 2000).…”

“…Two major rivers -the Changjiang (Yangtze) and Huanghe (Yellow) -drain into the CMS, with corresponding watersheds and river networks of both fluvial systems having been strongly impacted by anthropogenic disturbances over the last millennium (Li et al, 2016;Li & Daler, 2004;Saito et al, 2001). In addition to diverse, and time-evolving inputs, complex processes operating within the CMS impart strong gradients in carbon processing and dynamics that hinder extrapolations and derivation of system-wide properties and fluxes.…”

In Situ and Satellite Observations of Phytoplankton Size Classes in the Entire Continental Shelf Sea, China

“…Spatial distribution is closely related to the competitive abilities of different PSCs in response to environmental conditions. Figures b and c showed that salinity and temperature were higher in the central YS and the offshore ECS, due to the influence of Yellow Sea warm current, Taiwan warm current, and Kuroshio (Li et al, ; Quan et al, ; Yu et al, ). Results in section 3.1 revealed that temperature and salinity were correlated to the phytoplankton size structure, which might serve to explain why nano and picoplankton had higher concentrations and percentages offshore.…”

“…Indeed, higher dissolved inorganic nitrogen, phosphate, and silicate along coastlines and in the Changjiang Estuary and its adjacent areas were observed (Gong et al, ; Guo et al, ; Liu et al, ; Wang et al, ; Zhang et al, ), supporting our results that micro and nanoplankton were distributed with higher percentages in nearshore areas (Figure ). With the enhanced solar radiation in April, sea surface temperature increased and the stratification occurred in the central YS (Li et al, ; Yu et al, ), preventing the supplementary of nutrients in the surface. Availability of nutrients became the major limiting factor for the growth of large‐sized phytoplankton in more oligotrophic environments (Marañón, ).…”