Dynamics of fossil fuel CO2 neutralization by marine CaCO3

A detailed model of the ocean circulation and carbon cycle was coupled to a mechanistic model of CaCO3 diagenesis in deep sea sediments to simulate the millennium‐scale response of the oceans to future fossil fuel CO2 emissions to the atmosphere and deep sea. Simulations of deep sea injection of CO2 show that CaCO3 dissolution is sensitive to passage of high‐CO2 waters through the Atlantic Ocean, but CaCO3 dissolution has a negligible impact on atmospheric pCO2 or the atmospheric stabilization CO2 emission in the coming centuries. The ultimate fate of the fossil fuel CO2 will be to react with CaCO3 on the seafloor and on land. An initial CaCO3 dissolution spike reverses the net sedimentation rate in the ocean until it is attenuated by an enhanced vertical gradient of alkalinity after about 1000 years. The magnitude of the initial spike is sensitive to assumptions about the kinetics for CaCO3 dissolution, but subsequent behavior appears to be less model dependent. Neutralization by seafloor CaCO3 occurs on a timescale of 5–6 kyr, and is limited to at most 60–70% of the fossil fuel release, even if the fossil fuel release is smaller than the seafloor erodible inventory of CaCO3. Additional neutralization by terrestrial CaCO3 restores a balance between CaCO3 weathering and seafloor accumulation on a timescale of 8.5 kyr, while the deficit of seafloor CaCO3 (the lysocline) is replenished with an e‐folding timescale of approximately 18 kyr. The final equilibrium with CaCO3 leaves 7–8% of the fossil fuel CO2 remaining in the atmosphere, to be neutralized by the silicate rock cycle on a time frame of hundreds of thousands of years.

[1]  David Archer,et al.  Multiple timescales for neutralization of fossil fuel CO2 , 1997 .

[2]  David Archer,et al.  A data-driven model of the global calcite lysocline , 1996 .

[3]  Atul K. Jain,et al.  A globally aggregated reconstruction of cycles of carbon and its isotopes , 1996 .

[4]  R. Bacastow,et al.  Effectiveness of CO2 sequestration in the post-industrial ocean , 1996 .

[5]  Martin Heimann,et al.  Global and hemispheric CO2 sinks deduced from changes in atmospheric O2 concentration , 1996, Nature.

[6]  David Archer,et al.  An atlas of the distribution of calcium carbonate in sediments of the deep sea , 1996 .

[7]  R. Jahnke,et al.  The global ocean flux of particulate organic carbon: Areal distribution and magnitude , 1996 .

[8]  J. Edmonds,et al.  Economic and environmental choices in the stabilization of atmospheric CO2 concentrations , 1996, Nature.

[9]  Accounting for the missing carbon-sink with the CO2-fertilization effect , 1996 .

[10]  P. Ciais,et al.  A Large Northern Hemisphere Terrestrial CO2 Sink Indicated by the 13C/12C Ratio of Atmospheric CO2 , 1995, Science.

[11]  Nobuhiko Handa,et al.  Direct ocean disposal of carbon dioxide , 1995 .

[12]  J. Houghton.  Climate change 1994 : radiative forcing of climate change and an evaluation of the IPCC IS92 emission scenarios , 1995 .

[13]  The effectiveness of marine CO2 disposal , 1994 .

[14]  D. Archer,et al.  Respiration and dissolution in the sediments of the western North Atlantic: estimates from models of in situ microelectrode measurements of porewater oxygen and pH , 1994 .

[15]  Ian G. Enting,et al.  Future emissions and concentrations of carbon dioxide: Key ocean / atmosphere / land analyses , 1994 .

[16]  J. Milliman.  Production and accumulation of calcium carbonate in the ocean: Budget of a nonsteady state , 1993 .

[17]  E. Maier‐Reimer,et al.  Geochemical cycles in an Ocean General Circulation Model , 1993 .

[18]  Dwain F. Spencer,et al.  The capacity of the deep oceans to absorb carbon dioxide , 1993 .

[19]  E. Maier‐Reimer.  The biological pump in the greenhouse , 1993 .

[20]  Syukuro Manabe,et al.  Century-scale effects of increased atmospheric C02 on the ocean–atmosphere system , 1993, Nature.

[21]  C. Kinoshita,et al.  Projected Impact of Deep Ocean Carbon Dioxide Discharge on Atmospheric CO2 Concentrations , 1992 .

[22]  J. Sarmiento,et al.  A perturbation simulation of CO2 uptake in an ocean general circulation model , 1992 .

[23]  J. Kasting,et al.  Effects of fuel and forest conservation on future levels of atmospheric carbon dioxide. , 1992, Global and planetary change.

[24]  David Archer,et al.  Modeling the calcite lysocline , 1991 .

[25]  S. Noriki,et al.  Particulate fluxes of carbonate and organic carbon in the ocean. Is the marine biological activity working as a sink of the atmospheric carbon , 1991 .

[26]  D. Hammond,et al.  In situ measurements of calcium carbonate dissolution rates in deep-sea sediments , 1990 .

[27]  John W. Morse,et al.  Geochemistry of Sedimentary Carbonates , 1990 .

[28]  E. Sundquist.  Influence of deep-sea benthic processes on atmospheric CO2 , 1990, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[29]  I. Fung,et al.  Observational Contrains on the Global Atmospheric Co2 Budget , 1990, Science.

[30]  D. Archer,et al.  Dissolution of calcite in deep-sea sediments: pH and O2 microelectrode results , 1989 .

[31]  C. Gregor.  Chemical cycles in the evolution of the earth , 1988 .

[32]  K. Hasselmann,et al.  Transport and storage of CO2 in the ocean ——an inorganic ocean-circulation carbon cycle model , 1987 .

[33]  Robert A. Berner,et al.  The Global Water Cycle , 1987 .

[34]  W. Broecker,et al.  The role of CaCO3 compensation in the glacial to interglacial atmospheric CO2 change , 1987 .

[35]  David M. Karl,et al.  VERTEX: carbon cycling in the northeast Pacific , 1987 .

[36]  E. Sundquist.  Geologic Analogs: Their Value and Limitations in Carbon Dioxide Research , 1986 .

[37]  E. Boyle.  Chemical Accumulation Variations Under the Peru Current During the Past , 1983 .

[38]  R. Garrels,et al.  The carbonate-silicate geochemical cycle and its effect on atmospheric carbon dioxide over the past 100 million years , 1983 .

[39]  Paul B. Hays,et al.  A negative feedback mechanism for the long‐term stabilization of Earth's surface temperature , 1981 .

[40]  R. Keir.  The dissolution kinetics of biogenic calcium carbonates in seawater , 1980 .

[41]  Wallace S. Broecker,et al.  Atmospheric response to deep-sea injections of fossil-fuel carbon dioxide , 1979 .

[42]  C. Marchetti.  On geoengineering and the CO2 problem , 1977 .

[43]  R. Berner,et al.  Dissolution kinetics of calcium carbonate in sea water; IV, Theory of calcite dissolution , 1974 .