How do the Yangtze River and other rivers affect the seafloor of the East China Sea?

The Yangtze River and other rivers, such as the Huang He, play a primary role in shaping the seafloor of the East China Sea by depositing vast quantities of sediment.1

These rivers transport immense loads of alluvium and suspended material—with the Yangtze alone carrying between 430 million and 500 million tons annually—which settle in the shallow shelf areas of the sea. This deposition is facilitated by the sea's geologic structure, where rock ridges near the northern limits and the edge of the continental shelf act as barriers that trap the sediment brought down from the mainland. In these areas between the ridges, the accumulated sediment can reach up to one mile in thickness.12

As a result of this continuous deposition at the mouth of the Yangtze, the river's delta extends into the sea by an average of one mile every hundred years. While these shallow shelf regions are covered by river-borne sediments, coarser sands, muds, and oozes are found in other parts of the seafloor.21