Variability of oceanic carbon cycling and its relation to the ocean acidification in the North Pacific Ocean

Chair: Joellen Russell

Fei Chai (1) and Peng Xiu (2)
1School of Marine Sciences, University of Maine, Orono, ME, USA. E-mail:
1State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China

The ocean plays an important role in regulating global carbon cycle by taking up and releasing carbon dioxide (CO2) from and to the atmosphere simultaneously. The ocean has absorbed about 50% of CO2 emitted to the atmosphere by fossil fuel burning, and this ability has been suggested to continue at a relatively stable rate of 1.4- 1.8 PgC per year. The direct impact of ocean absorbing CO2 is leading to the ocean acidification (OA) that can affect biological activities and the oceanic CO2 system. Here, we propose a coupled three-dimensional modeling study to investigate the dynamics of the carbonate system in the North Pacific Ocean, based on the Regional Ocean Modeling System (ROMS) and the biogeochemical model, CoSiNE model, along with a carbonate system. The model results are compared and constrained with available in-situ measurements all over the Pacific Ocean. Further analysis of the model results indicates that the carbonate system in the North Pacific Ocean has strong spatial and temporal variations in terms of sea p CO2, pH, and the aragonite saturation state. Long-term trends of these variables show conspicuous spatial variability that could be related to the local physical and biogeochemical conditions. We also analyze the impacts and feedbacks of OA to the sea p CO2 and sea-air CO2 flux. This modeling study allows us to look into the detailed mechanisms in regulating oceanic carbonate system with high spatial and temporal resolutions that field observations normally cannot provide.