How Does One of the Largest Hypoxia in the World Occur on the Shelf of the East China Sea?

Tuesday, 16 December 2014
Feng Zhou1, Huijie Xue2, Daji Huang3, Fei Chai2, Peng Xiu4, Jiliang Xuan1 and Xiaobo Ni1, (1)State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration, Hangzhou, China, (2)University of Maine, Orono, ME, United States, (3)Second Institute of Oceanography, State Oceanographic Administration of China, Hangzhou, China, (4)SCSIO South China Sea Institute of Oceanology, Chinese Acaademy of Sciences, Guangzhou, China
The continental shelf of the East China Sea has been experiencing a fast growing input of terrestrial nutrients in recent decades, in additional to constant incursion of marginal nutrients sources with low oxygen concentration, which together could be responsible for one of the largest hypoxic zone off the Changjiang River estuary and the adjacent coast especially in the northern East China Sea. However, the onset and spreading of hypoxia varies from year to year, and its mechanism is poorly known due to a variety of nutrient cycling and complicate circulation systems. Intensive survey suggested association of the tremendous increase in the area of the hypoxic zone with strong cross-shelf exchanges and steady growth of riverine nutrients for 2006. A high-resolution 3D primitive equation model coupled with a 13-component biological module has been applied to the area in an attempt to evaluate the terrestrial and marginal contributions. Sediment processes is simplified by formulating a relation of the oxidation of carbon and nitrification of ammonium to nitrate with oxygen consumption. The biological module is based on the Carbon, Silicate, Nitrogen Ecosystem Model (CoSiNE).