Acta Geographica Sinica ›› 2005, Vol. 60 ›› Issue (2): 328-336.doi: 10.11821/xb200502016

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Inorganic Nitrogen Fluxes at the Sediment-water Interface in Tidal Flats of the Yangtze Estuary

CHEN Zhenlou, WANG Dongqi, XU Shiyuan, ZHANG Xingzheng, LIU Jie   

  1. Key Laboratory of Geographical Information Science of the Ministry of Education, College of Resource and Environmental Science, East China Normal University, Shanghai 200062, China
  • Received:2004-09-16 Revised:2004-11-18 Online:2005-03-25 Published:2005-03-25
  • Supported by:

    National Natural Science Foundation of China, No.40173030; No.40131020; Excellent Young Teacher Program of the Ministry of Education; Key Program of Shanghai Science Foundation, No.02DJ14029


Inorganic nitrogen fluxes at the sediment-water interface of seven typical sites in tidal flats of the Yangtze estuary had been determined seasonally during more than three years. The results revealed that the sediment-water exchanges of inorganic nitrogen appeared to be of complicated spatial differences and seasonal variations. The measured fluxes of NO-3-N and NH+4-N in the Yangtze estuary were higher than those in other estuaries, varying respectively from -32.82 to 24.13 mmol·m-2·d-1 and from -18.45 to 10.65 mmol·m-2·d-1. However, the fluxes of NO-2/sub>-N were very low, and only varied from -1.15 to 2.82 mmol·m-2·d-1. The spatial and seasonal differences between the upper and lower estuary for the NO-3-N fluxes were observed clearly, but the NH+4-N fluxes exhibited the spatial and seasonal differences between the south and north bank. It had been recognized that the NH+4-N exchange behavior was mainly controlled by the salinity, whereas the NO-3-N exchange behavior was influenced by the different combinations of the sediment grain size, nitrate concentration in overlying water, sediment organic matter content, water temperature and dissolved oxygen concentration.

Key words: inorganic nitrogen, exchange flux, sediment-water interface, tidal flat, Yangtze estuary