The Three Gorges Dam: Reducing the upwelling and thus productivity in the East China Sea

It has been well documented that since 1850 the amount of phosphorus as well as nitrogen input to coastal seas around the world has increased by a factor of ten, thus raising concern over eutrophication, Here, evidence is provided to show that despite a large riverine input of nutrients to the East China Sea (ECS), only a small fraction (7% for P and 33% for N) of the external nutrient supply supporting ne iv production is provided by the total riverine input. The major nutrient supply in fact originates from the on-shore advection of the subsurface Kuroshio waters. Whether the ECS will become eutrophicated, therefore, actually depends on the amount of phosphorus supply supported by on-shore advection. This supply, though, will very likely be reduced after the completion of the Three Gorges Dam, and this will lead to a diminished productivity in the ECS.