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Circulation, biogeochemistry and carbon cycling in ocean margins
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Solubility controls carbonate chemistry with local modifications in North American ocean margins (Invited)
Monday 7th @ 0930-0950, Concert Hall
Wei-Jun Cai* , School School of Marine Science and Policy, University of Delaware
Yuanyuan Xu, School School of Marine Science and Policy, University of Delaware
Richard A. Feely, NOAA Pacific Marine Environmental Laboratory
Leticia Barbero, NOAA Atlantic Oceanographic and Meteorological Laboratory
Simone Alin, NOAA Pacific Marine Environmental Laboratory
Jessica Cross, NOAA Pacific Marine Environmental Laboratory
Adrienne Sutton, NOAA Pacific Marine Environmental Laboratory
Kumiko Azetsu-Scott, Department of Fisheries and Oceans, Canada, Bedford Institute of Oceanography
Bror Johnson, University of New Hampshire, Ocean Process Analysis Laboratory
Presenter Email: wcai@udel.edu |
| The increase of anthropogenic CO2 in the atmosphere has acidified the ocean and affected the health of organisms and ecosystems therein. While studies have demonstrated greater ocean acidification (OA) and more complex processes in coastal waters than open oceans, mechanisms controlling large spatial distribution patterns in coastal oceans are still not well understood. We report here recently measured carbonate parameter distributions in North American ocean margins and show that carbonate saturation state (omega) and total dissolved inorganic carbon (DIC) distributions in the US and Canadian eastern, Gulf of Mexico, and Gulf of Alaska coastal waters demonstrate a remarkable consistency with predictions from a solubility control mechanism which dictates more atmospheric CO2 uptake and drives carbonate (CO32-) and omega low in cold northern waters and less so in warm southern waters while there exist large local variabilities in pH and CO2 partial pressure (pCO2). The solubility driven mechanism is greatly modified by upwelling and biological production in the California Current System along the US West Coast with upwelling leading to high pCO2 and low omega and pH and biological production to the opposite distributions. We further show that contrasting features between solubility-controlled DIC and omega and local process-controlled pH and pCO2 are determined by the nature of marine acid-base equilibrium, with bicarbonate (HCO3-) and CO32- being the major components, which are insensitive to short-term local processes, and H+ and [CO2] being minor components and most sensitive to short-term local processes. The large signals observed in coastal oceans may foreshadow future OA in open oceans and emphasize the needs for understanding contrasting organismal responses to omega and pH under a higher CO2 and warmer future ocean scenario. |
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