Assessment of eutrophication in the Yangtze River estuary and the adjacent East China Sea, China

Abstract

With the recent acceleration in urbanization and industrialization, the Yangtze River estuary has become increasingly challenged by various destructive threats to its ecosystem such as the frequent occurrence of harmful algal blooms. Eutrophication data measured around the Yangtze River estuary in 2006 was analyzed by means of computer programming in order to study nutrient pollution surrounding the Yangtze River Estuary and its adjacent East China Sea. Results indicated that the primary source of inorganic pollution was attributed to dissolved inorganic nitrogen in the estuary. With respect to seasonal effects, pollution levels during winter are recorded as being the highest while minimum effects are seen to appear during summer. Changes in pollution distribution were related to the variation of the runoff from the Yangtze River. However, where runoff volume was small, high concentration centers of nutrient salt appeared within the estuary and offshore regions. In addition, the Yangtze River Estuary has been repeatedly subject to critical outbreaks of algal blooms, while the growth of phytoplankton in this area was mainly limited by phosphate.