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General Session 1: Physical oceanic processes: Dynamics and physical-biological-biogeochemical interactions |
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Simulated ocean carbon cycle response to climate change
Monday 9th @ 1520-1535
Conference Hall
Long Cao* , Zhejiang University
Han Zhang, Zhejiang University
Meidi Zheng, Zhejiang University
Ken Caldeira, Carnegie Institution
Presenter Email: longcao@zju.edu.cn
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| The ocean carbon cycle, via its effect on air-sea CO2 exchange, plays a key role in regulating the amount of atmospheric CO2. The cycling of carbon in the ocean is governed by a number of complex processes including carbonate chemistry, ocean physical transport, and marine biological conversion. These processes occur over different timescales and are expected to change in response to climate change. Thus, a process-based understanding of how increasing atmospheric CO2 and CO2-induced warming would influence the ocean carbon cycle is crucial for a reliable projection of future climate change.
We use the approach of Earth system modeling to investigate change of the ocean carbon cycle in response to increasing atmospheric CO2 and CO2-induced global warming. We conduct a set of simulations to disentangle the effect of change in carbonate chemistry, ocean physical transport of carbon, and biological activities on oceanic uptake of atmospheric CO2. Simulations show that temperature-induced changes in marine biology influences oceanic CO2 uptake by an amount that is comparable to that caused by changes in carbonate chemistry and ocean physical transport. We analyze mechanisms underlying response of the ocean carbon cycle to climate change with particular attention to the effect from different processes of marine biology.
To further understand the long-term change of the ocean carbon cycle and ocean acidification over several thousands of years, simulations are performed by including the processes of deep-sea sedimentation and continental weathering. Simulation results show that over timescales of more than a few thousands of years, deep-sea sedimentation and continental weathering substantially increase the amount of anthropogenic CO2 absorbed by the ocean, but at the same time mitigate simulated ocean acidification.
This study has important implication for understanding possible changes in the ocean carbon cycle in response to CO2-induced warming, which is important for projection of climate change and ocean acidification.
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