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General Session 1: Physical oceanic processes: Dynamics and physical-biological-biogeochemical interactions |
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Future ecosystem change in a coastal upwelling system
Monday 9th @ 1100-1115
Conference Hall
Peng Xiu* , South China Sea Institute of Oceanology, Chinese Academy of Sciences
Fei Chai, State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration
Enrique N. Curchitser, Rutgers University
Frederic S. Castruccio, National Center for Atmospheric Research
Presenter Email: pxiu@scsio.ac.cn
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| A coupled model is used to study the dynamics of physical and biological processes in the central California Current Systems, on seasonal, interannual, decadal, and future timescales. Comparisons of model results with remote sensing and in-situ observations indicate that the model can reproduce the spatial patterns of key variables (temperature, nutrients, chlorophyll etc.) both at the surface and at depth. In the coastal upwelling system, simulated coastal species (diatom and mesozooplankton) peak in the late upwelling period (May-July), while the oceanic species (picoplankton and micozooplantkon) reach annual maxima in the oceanic period (August-October). In the central CCS, we found the changing control mechanisms on ecosystem dynamics when moving away from the coast. The low-frequency variability of physical and biological processes was generally controlled by alongshore winds in the coastal upwelling region (0-150 km from the coast), by local vertical mixing and stratification in the offshore oceanic region (500-1000 km offshore), and by local vertical mixing and stratification as well as offshore transport from the coast in the transition zone (150-500 km offshore). With a future projection, the model has predicted increased upwelling intensity associated with stronger alongshore winds in the coastal region, and enhanced upper stratification in the open ocean. Warming in the open ocean pushes isothermals down to make contact with water masses with higher nutrient concentrations, leading to increased nutrient concentrations in the deep source waters of the CCS. |
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