Program
 
General Session 1: Physical oceanic processes: Dynamics and physical-biological-biogeochemical interactions
 

 
 
1435
Biogeochemical response to the rotating layered circulation in the China Seas
Monday 9th @ 1435-1450
Conference Hall
Jianping Gan* , Department of Mathematics and Division of Environment, Hong Kong University of Science and Technology
Minhan Dai, State Key Laboratory of Marine Environmental Science, Xiamen University
Zhongming Lu, Division of Environment, Hong Kong University of Science and Technology
Presenter Email: magan@ust.hk
The circulation in the China Seas (CS) can be depicted by rotating layered circulations in the respective seas (South China Sea, East China Sea and Yellow Sea) as a result of extrinsical forcing by the water exchange with adjacent oceans and intrinsical forcing by the monsoonal wind-forced current over topography (Gan et al., 2016, JGR). Biogeochemical process in the CS is largely linked with the material fluxes associated with the rotating layered circulations. Using a newly developed China Sea Multi-Scale Ocean Modeling System (CMOMS), we examine the biogeochemical responses to material fluxes due to the rotating layered circulations, terrestrial inputs from rivers and the water exchanges in the CS. The relative importance of these biophysical intrinsic/extrinsic forcing functions is quantified and linked with biological activities to assess the spatiotemporal variability of the biogeochemical processes in the respective seas. In the SCS, nutrients in upper layer are mainly sourced by the upward advection of the deep intrusive water through Luzon Strait due to the rotating layered circulation. The physical transport associated with the three-dimensional circulation and biological processes associated with assimilation and remineralization serve as the major source or sink of nutrients. In the East China Sea, nutrient inputs from the river and along-shelf transport associated with a rotating layered circulation exceed the supply from the Kuroshio intrusion in both dry and wet seasons. Unique nutrient dynamics associated with enhanced P turnover rates, PO4 supply, adapted N:P uptake ratio and photosynthesis-irradiance relationship is identified in the East China Sea.