TERRAPUB Journal of Oceanography

Journal of Oceanography, Vol. 61 (No. 2), pp. 343-357, 2005

Simulations of Annual Cycle of Phytoplankton Production and the Utilization of Nitrogen in the Yellow Sea

Tian Tian1,2*, Hao Wei1,3, Jian Su1 and Changsoo Chung4

1Institute of Physical Oceanography, Ocean University of China, Qingdao 266003, China
2Environmental Science and Engineering College, Ocean University of China, Qingdao 266003, China
3Key Physical Oceanography laboratory of State Education Ministry, Qingdao 266003, China
4Korea Ocean Research & Development Institute, Seoul 425-600, Korea

(Received 4 April 2004; in revised form 31 August 2004; accepted 1 November 2004)

Abstract: A nutrient dynamic model coupled with a 3D physical model has been developed to study the annual cycle of phytoplankton production in the Yellow Sea. The biological model involves interactions between inorganic nitrogen (nitrate and ammonium), phosphate and phytoplankton biomass. The model successfully reproduces the main features of phytoplankton-nutrient variation and dynamics of production. 1. The well-mixed coastal water is characterized by high primary production, as well as high new production. 2. In summer, the convergence of tidal front is an important hydrodynamic process, which contributes to high biomass at frontal areas. 3. The evolution of phytoplankton blooms and thermocline in the central region demonstrate that mixing is a dominant factor to the production in the Yellow Sea. In this simulation, nitrate- and ammonium-based productions are estimated regionally and temporally. The northern Yellow Sea is one of the highly ranked regions in the Yellow Sea for the capability of fixing carbon and nitrogen. The annual averaged f-ratio of 0.37 indicates that regenerated production prevails over the Yellow Sea. The result also shows that phosphate is the major nutrient, limiting phytoplankton growth throughout the year and it can be an indicator to predict the bloom magnitude. Finally, the relative roles of external nutrient sources have been evaluated, and benthic fluxes might play a significant role in compensating 54.6% of new nitrogen for new production consumption.

*Corresponding author E-mail: tiantian@ouc.edu.cn

[Full text] (PDF 4.5 MB)