Assessing the potential long-term increase of oceanic fossil fuel CO2 uptake due to CO2-calcification feedback A. Ridgwell1, I. Zondervan2, J. C. Hargreaves3, J. Bijma2, and T. M. Lenton4 1School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS UK 2Biogeosciences, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany 3Frontier Research Center for Global Change, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan 4School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
Abstract. Plankton manipulation experiments exhibit a wide range of sensitivities of
biogenic calcification to simulated anthropogenic acidification of the
ocean, with the "lab rat" of planktic calcifiers, Emiliania huxleyi apparently not
representative of calcification generally. We assess the implications of
this observational uncertainty by creating an ensemble of realizations of an
Earth system model that encapsulates a comparable range of uncertainty in
calcification response to ocean acidification. We predict that a substantial
reduction in marine carbonate production is possible in the future, with
enhanced ocean CO2 sequestration across the model ensemble driving a
4–13% reduction in the year 3000 atmospheric fossil fuel CO2 burden.
Concurrent changes in ocean circulation and surface temperatures in the
model contribute about one third to the increase in CO2 uptake. We find
that uncertainty in the predicted strength of CO2-calcification
feedback seems to be dominated by the assumption as to which species of
calcifier contribute most to carbonate production in the open ocean.
Citation: Ridgwell, A., Zondervan, I., Hargreaves, J. C., Bijma, J., and Lenton, T. M.: Assessing the potential long-term increase of oceanic fossil fuel CO2 uptake due to CO2-calcification feedback, Biogeosciences, 4, 481-492, doi:10.5194/bg-4-481-2007, 2007.