Han Zhang

and 6 more

The effect of warming-induced changes in different marine physical, chemical, and biological processes on ocean acidification has been largely overlooked. This study uses an Earth system model to investigate the impacts of warming-induced changes in marine dynamical and thermodynamical processes, CO2 solubility, and biological processes on ocean acidification. Under the representative concentration pathway RCP8.5 and its extension, relative to the simulation without CO2-induced warming effects on the ocean carbon cyle, by year 2500, warming increases global ocean mean [CO32-] by 11.6 μmol kg-1, of which 53% is associated with warming-induced changes in dynamical and thermodynamical processes, 20% is associated with warming-induced changes in CO2 solubility, and 27% is associated with warming-induced changes in ocean biological rates. In the Arc-Atlantic Ocean, mainly due to the greater temperature-induced changes in dynamical and thermodynamical processes, the total warming effect on the ocean carbon cycle acts to increase ocean mean [CO32-] by a considerable 60%, in particular, up to 109% in the depth of ~2500 m, by year 2500. In our simulated results, warming-induced changes in individual biological processes, including phytoplankton growth and mortality rates, and detritus remineralization rate, as well as total biological effects are found to affect ocean acidification by an amount comparable to or greater than that caused by warming-induced changes in dynamical and thermodynamical processes and CO2 solubility. Our study highlights the potentially important role of CO2-induced warming in ocean acidification and the ocean carbon cycle.