Program     Carbon Cycle in the South China Sea: Budget, Controls and Global Implications       Poster Seasonal variation of primary production in the northern South China Sea: integrated effects of drivers P-SPS3-05 Yuyuan Xie, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, China Lizhen Lin, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, China Haoran Liu* , Department of Environmental Sciences, Xiamen University, Xiamen, Fujian, China Bangqin Huang, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, China Presenter Email: xieyuyuan@hotmail.com The South China Sea (SCS), which is one of the largest marginal seas on earth, is in the edge of the southwestern North Pacific Ocean. The SCS has an area of 3.5*10^6 km2 with the average depth equals 1350 m. The northern boundary between the continent and the basin is the wide shelf of depths < 200 m, while the basin is deep up to 5000 m. Although some current characteristics of the SCS basin mimic those in the major ocean basins, the seasonal pattern of phytoplankton biomass and primary production is on the opposite side. Through the implementation of CHOICE-C I project, we have measured the seasonal variation of primary production in the northern SCS. The CHOICE-C II project continues to dig into the controlling mechanisms. In this study, we employed a diagnostic model to analyze those data for disclosing what aspects of the sea and how they are mastering the contrasting seasonal changes in primary production.