CPD Climate of the Past Discussions CPD 1814-9359 Copernicus GmbH Göttingen, Germany 10.5194/cpd-5-1259-2009 Glacial – interglacial atmospheric CO<sub>2</sub> change: a possible "standing volume" effect on deep-ocean carbon sequestration Skinner L. C. 1 Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, CB2 3EQ, Cambridge, UK 04 05 2009 5 3 1259 1296 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.clim-past-discuss.net/5/1259/2009/cpd-5-1259-2009.html The full text article is available as a PDF file from http://www.clim-past-discuss.net/5/1259/2009/cpd-5-1259-2009.pdf

So far, the exploration of possible mechanisms for glacial atmospheric CO<sub>2</sub> draw-down and marine carbon sequestration has focussed almost exclusively on dynamic or kinetic processes (i.e. variable mixing-, equilibration- or export rates). Here an attempt is made to underline instead the possible importance of changes in the standing volumes of intra-oceanic carbon reservoirs (i.e. different water-masses) in setting the total marine carbon inventory. By way of illustration, a simple mechanism is proposed for enhancing the carbon storage capacity of the deep sea, which operates via an increase in the volume of relatively carbon-enriched AABW-like deep-water filling the ocean basins. Given the hypsometry of the ocean floor and an active biological pump, the water-mass that fills more than the bottom 3 km of the ocean will essentially determine the carbon content of the marine reservoir. A set of simple box-model experiments confirm the expectation that a deep sea dominated by AABW-like deep-water holds more CO<sub>2</sub>, prior to any additional changes in ocean overturning rate, biological export or ocean-atmosphere exchange. The magnitude of this "standing volume effect" might be as large as the contributions that have been attributed to carbonate compensation, the thermodynamic solubility pump or the biological pump for example. If incorporated into the list of factors that have contributed to marine carbon sequestration during past glaciations, this standing volume mechanism may help to reduce the amount of glacial – interglacial CO<sub>2</sub> change that remains to be explained by other mechanisms that are difficult to assess in the geological archive, such as reduced mass transport or mixing rates in particular. This in turn could help narrow the search for forcing conditions capable of pushing the global carbon cycle between glacial and interglacial modes.

 References Archer, D. and Maier-Reimer, E.: Effect of deep-sea sedimentary calcite preservation on atmospheric CO2 concentration, Nature, 367, 260–263, 1994. Archer, D., Winguth, A., Lea, D. W., and Mahowald, N.: What caused the glacial/interglacial atmospheric $p$CO2 cycles?, Rev. Geophys., 38(2), 159–189, 2000. Bard, E.: Correction of accelerator mass spectrometry 14C ages measured in planktonic foraminifera: Paleoceanographic implications, Paleoceanography, 3(6), 635–645, 1988. Boyle, E.: Cadmium and d13C paleochemical ocean distributions during the Stage 2 glacial maximum, Ann. Rev. Earth Planet. Sci., 20, 245–287, 1992. Boyle, E. A.: Cadmium: chemical tracer fro deepwater paleoceanography, Paleoceanography, 3, 471–489, 1988a. Boyle, E. A.: The role of vertical fractionation in controlling late Quaternary atmospheric carbon dioxide, J. Geophys. Res., 93(C12), 15701–15714, 1988b. Broecker, W. S.: Glacial to interglacial changes in ocean chemistry, Prog. Oceanogr., 11, 151–197, 1982a. Broecker, W. S.: Ocean chemistry during glacial time, Geochim. Cosmochim. Ac., 46, 1698–1705, 1982b. Broecker, W. S. and Peng, T. H.: Tracers in the Sea, Eldigio Press, Palisades, New York, USA, 1982. Broecker, W. S. and Peng, T.-H.: The cause of the glacial to interglacial atmospheric CO2 change: a polar alkalinity hypothesis, Global Biogeochem. Cy., 3(3), 215–239, 1989. Brovkin, V., Ganopolski, A., Archer, D., and Rahmstorf, S.: Lowering glacial atmospheric CO<sub>2</sub> in response to changes in oceanic circulation and marien biogeochemistry, Paleoceanography, 22, PA4202, 1–14, 2007. Cox, M. D.: An idealized model of the world ocean. Part I: The global-scale water masses, J. Phys. Oceanogr., 19, 1730–1752, 1989. Curry, W. B., Duplessy, J. C., Labeyrie, L. D., and Shackleton, N. J.: Changes in the distribution of d13C of deep water sigma-CO<sub>2</sub> between the last glaciation and the Holocene, Paleoceanography, 3(3), 317–341, 1988. Curry, W. B. and Oppo, D. W.: Glacial water mass geometry and the distribution of d13C of Sigma-CO<sub>2</sub> in the western Atlantic Ocean, Paleoceanography, 20, PA1017, doi:10.1029/2004PA001021, 2005. Denman, K. L., Brasseur, G., Chidthaisong, A., Ciasis, P., Cox, P. M., Dickinson, R. E., Hauglustaine, D., Heinze, C., Holland, E., Jacob, D., Lohmann, U., Ramachandran, S., da Silva Dias, P. L., Wofsy, S. C., and Zhang, X.: Couplings between changes in the climate system and biogeochemistry, in: Climate Change 2007: The Physical Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, New York, USA, 2007. Dugdale, R. C.: Nutrient limitation in the sea: dynamics, identification, and significance, Limnol. Oceanogr., 12, 685–695, 1967. Duplessy, J.-C., Shackleton, N. J., Fairbanks, R. G., Labeyrie, L., Oppo, D., and Kallel, N.: Deep water source variations during the last climatic cycle and their impact on global deep water circulation, Paleoceanography, 3, 343–360, 1988. Ganachaud, A. and Wunsch, C.: Improved estimates of global ocean circulation, heat transport and mixing from hydrographic data, Nature, 408, 453–457, 2000. Gildor, H. and Tziperman, E.: Physical mechanisms behind biogeochemical glacial-interglacial CO<sub>2</sub> variations, Geophys. Res. Lett., 28(12), 2421–2424, 2001. Gnanadesikan, A., de Boer, A. M., and Mignone, B. K.: A simple theory of the pycnocline and overturning revisited, in: Ocean circulation: mechanisms and impacts, edited by: Schmittner, A., Chiang, C. H., and Hemming, S. R., Geophysical Monograph, AGU, Washington DC, 19–32, 2007. Goldstein, S. L. and Hemming, S. R.: Long-lived isotopic tracers in oceanography, paleoceanography and ice-sheet dynamics, in: Treatise on Geochemistry, edited by: Elderfield, H., Elsevier, 453–489, 2003. Gordon, A. L.: Comment on the South Atlantic's role in the global circulation, in: The South Atlantic: Present and Past Circulation, edited by: Wefer, G., Berger, A., Siedler, G., and Webb, D. J., Springer-Verlag, Berlin Heidelberg, Germany, 121–124, 1996. Heinze, C., Maier-Reimer, E., and Winn, K.: Glacial $p$CO<sub>2</sub> reduction by the world ocean: Experiments with the Hamburg carbon cycle model, Paleoceanography, 6, 395–430, 1991. Hodell, D. A., Venz, K. A., Charles, C. D., and Ninneman, U. S.: Pleistocene vertical carbon isotope and carbonate gradients in the South Atlantic sector of the Southern Ocean, Geochem. Geophy. Geosy., 4(1), GC1004, doi:10.1029/2002GC000367, 2003. Ito, T. and Follows, M. J.: Preformed phosphate, soft tissue pump and atmospheric CO<sub>2</sub>, J. Mar. Res., 63, 813–839, 2005. Keeling, R. F. and Stephens, B. B.: Antarctic sea ice and the control of Pleistocene climate instability, Paleoceanography, 16(1), 112–131, 2001. Keigwin, L. D.: Radiocarbon and stable isotope constraints on Last Glacial Maximum and Younger Dryas ventilation in the western North Atlantic, Paleoceanography, 19, PA4012, 1–15, 2004. Keigwin, L. D. and Lehmann, S. J.: Deep circulation change linked to Heinrich event 1 and Younger Dryas in a mid-depth North Atlantic core, Paleoceanography, 9(2), 185–194, 1994. Key, R. M., Kozyr, A., Sabine, C., Lee, K., Wanninkhof, R., Bullister, J. L., Feely, R. A., Millero, F. J., Mordy, C., and Peng, T.-H.: A global ocean carbon climatology: Results from the Global Data Analysis Project (GLODAP), Global Biogeochem. Cy., 18, GB4031, 1–23, 2004. Kim, S.-J., Flato, G. M., and Boer, G. J.: A coupled climate model simulation of the Last Glacial Maximum, Part 2: approach to equilibrium, Clim. Dynam., 20, 635–661, 2003. Knox, F. and McElroy, M.: Changes in atmospheric CO<sub>2</sub>: influence of marine biota at high latitude, J. Geophys. Res., 89, 4629–4637, 1984. Kohler, P., Fischer, H., Munhoven, G., and Zeebe, R. E.: Quantitative interpretation of atmospheric carbon records over the last glacial termination, Global Biogeochem. Cy., 19, 1–24, 2005. Lynch-Steiglitz, J., Adkins, J. F., Curry, W. B., Dokken, T., Hall, I. R., Heguera, J. C., Hirschi, J. J.-M., Ivanova, E. V., Kissel, C., Marchal, O., Marchitto, T. M., McCave, I. N., McManus, J. F., Mulitza, S., Ninneman, U. S., Peeters, F. J. C., Yu, E.-F., and Zahn, R.: Atlantic meridional overturning circulation during the last glacial maximum, Science, 316, 66–69, 2007 Marchal, O. and Curry, W. B.: On the abyssal circulation in the glacial Atlantic, J. Phys. Oceanogr., 38, 2014–2037, 2008. Marchal, O., Stocker, T. F., and Joos, F.: A latitude-depth, circulation-biochemical ocean model for paleoclimate studies. Development and sensitivities, Tellus, 50B(3), 290–316, 1998. Marchitto, T. M. and Broecker, W.: Deep water mass geometry in the glacial Atlantic Ocean: A review of constraints from the paleonutrient proxy Cd/Ca, Geochem. Geophy. Geosy., 7(12), 1–16, 2005. Marchitto, T. M., Oppo, D. W., and Curry, W. B.: Paired benthic foraminiferal Cd/Ca and Zn/Ca evidence for a greatly increased presence of Southern Ocean Water in the glacial North Atlantic, Paleoceanography, 17(3), 10.11–10.16, 2002. Marinov, I., Gnadesikan, A., Toggweiler, J. R., and Sarmiento, J. L.: The Southern Ocean biogeochemical divide, Nature, 441, 964–967, 2006. Martin, J. H., Knauer, G. A., Karl, D. M., and Broenkow, W. W.: VERTEX: carbon cycling in the northeast Pacific, Deep Sea Res., 34, 267–286, 1987. Matsumoto, K.: Radiocarbon-based circulation age of the world oceans, J. Geophys. Res., 112(C), 1–7, 2007. Menard, H. W. and Smith, S. M.: Hypsometry of ocean basin provinces, J. Geophys. Res., 71(18), 4305–4325, 1966. Michel, E., Labeyrie, L., Duplessy, J.-C.. and Gorfti, N.: Could deep Subantarctic convection feed the worl deep basins during last glacial maximum?, Paleoceanography, 10(5), 927–942, 1995. Müller, S. A., Joos, F., Edwards, N. R., and Stocker, T. F.: Water mass distribution and ventilation time scales in a cost-efficient, three-dimensional ocena model, J. Climate, 19, 5479–5499, 2006. Najjar, R. G., Sarmiento, J. L., and Toggweiler, J. R.: Downward transport and fate of organic matter in the ocean: simulations with a general circulation model, Global Biogeochem. Cy., 6, 45–76, 1992. Naviera Garabato, A. C., Polzin, K. L., King, B. A., Heywood, K. J., and Visbeck, M.: Widespread intense turbulent mixing in the Southern Ocean, Science, 303, 210–213, 2004. Oppo, D. and Fairbanks, R. G.: Atlantic ocean thermohaline circulation of the last 150,000 years: Relationship to climate and atmospheric CO<sub>2</sub>, Paleoceanography, 5, 277–288, 1990. Oppo, D. W., Fairbanks, R. G., Gordon, A. L., and Shackleton, N. J.: Late Pleistocene Southern Ocean $d^13$C variability, Paleoceanography, 5, 43–54, 1990. Orsi, A. H., Johnson, G. C., and Bullister, J. L.: Circulation, mixing and production of Antarctic Bottom Water, Prog. Oceanogr., 43, 55–109, 1999. Peacock, S., Lane, E., and Restrepo, M.: A possible sequence of events for the generalized glacial - interglacial cycle, Global Biogeochem. Cy., 20, GB2010, 1–17, 2006. Piotrowski, A., Goldstein, S. L., Hemming, S. R., and Fairbanks, R. G.: Temporal relationships of carbon cycling and ocean circulation at glacial boundaries, Science, 307, 1933–1938, 2005. Piotrowski, A. M., Goldstein, S. L., Hemming, S. R., and Fairbanks, R. G.: Intensification and variability of ocean thermohaline circulation through the last deglaciation, Earth Planet. Sci. Lett., 225, 205–220, 2004. Redfield, A. C., Ketchum, B. H., and Richards, F. A.: The influence of organisms on the composition of sea water, in: The Sea, edited by: Hill, M. N., Wiley-Interscience, New York, USA, 26–77, 1962. Robinson, L. F., Adkins, J. F., Keigwin, L. D., Southon, J., Fernandez, D. P., Wang, S.-L., and Scheirer, D. S.: Radiocarbon variability in the western North Atlantic during the last deglaciation, Science, 310, 1469–1473, 2005. Rutberg, R. L., Heming, S. R., and Goldstein, S. L.: Reduced North Atlantic Deep Water flux to the glacial Southern Ocean inferred from neodymium isotope ratios, Nature, 405, 935–938, 2000. Sabine, C., Feely, R. A., Gruber, N., Key, R. M., Lee, K., Bullister, J. L., Wanninkhof, R., Wong, C. S., Wallace, D. W. R., Tilbrook, B., Millero, F. J., Peng, T.-H., Kozyr, A., Ono, T., and Rios, A. F.: The oceanic sink for anthropogenic CO<sub>2</sub>, Science, 305, 367–371, 2004. Sarmiento, J. L. and Toggweiler, R.: A new model for the role of the oceans in determining atmospheric $p$CO<sub>2</sub>, Nature, 308, 621–624, 1984. Schulz, M., Seidov, D., Sarnthein, M., and Stattegger, K.: Modeling ocean-atmosphere carbon budgets during the Last Glacial Maximum-Heinrich 1 meltwater event-Bolling transition, Int. J. Earth Sci. (Geol. Rundsch.), 90, 412–425, 2001. Shackleton, N. J.: The 100 000-year ice-age cycle identified and found to lag temperature, carbon dioxide and orbital eccentricity, Science, 289, 1897–1902, 2000. Shin, S. I., Liu, Z., Otto-Bliesner, B. L., Brady, E. C., Kutzbach, J. E., and Harrison, S. P.: A simulation of the last glacial maximumclimate using the NCAR-CCSM, Clim. Dynam., 20, 127–151, 2003. Siegenthaler, U., Stocker, T. F., Monnin, E., Luthi, D., Schwander, J., Stauffer, B., Raynaud, D., Barnola, J.-M., Fischer, H., Masson-Delmotte, V., and Jouzel, J.: Stable carbon cycle - climate relationship during the Late Pleistocene, Science, 310, 1313–1317, 2005. Siegenthaler, U. and Wenk, T.: Rapid atmospheric CO<sub>2</sub> variations and ocean circulation, Nature, 308, 5960, 624–625, 1984. Sigman, D. M. and Boyle, E. A.: Glacial/interglacial variations in atmospheric carbon dioxide, Nature, 407, 859–869, 2000. Sigman, D. M. and Haug, G. H.: The biological pump in the past, in: Treatise on Geochemistry, edited by: Elderfield, H., Elsevier, 491–528, 2003. Skinner, L. C. and Shackleton, N. J.: Rapid transient changes in Northeast Atlantic deep-water ventilation-age across Termination I, Paleoceanography, 19, 1–11, 2004. Speer, K., Rintoul, S. R., and Sloyan, B.: The diabatic deacon cell, J. Phys. Oceanogr., 30, 3212–3222, 2000. Stuiver, M. and Polach, H. A.: Reporting of 14C data, Radiocarbon, 19(3), 355–363, 1977. Toggweiler, J. R.: Variation of atmospheric CO<sub>2</sub> by ventilation of the ocean's deepest water, Paleoceanography, 14(5), 571–588, 1999. Toggweiler, J. R., Murnane, R., Carson, S., Gnanadesikan, A., and Sarmiento, J. L.: Representation of the carbon cycle in box models and GCMs: 2. Organic pump, Global Biogeochem. Cy., 17(1), 27.21–27.13, 2003. Toggweiler, J. R., Russell, J. L., and Carson, S. R.: Midlatitude westerlies, atmospheric CO2, and climate change during the ice-ages, Paleoceanography, 21, 1–15, 2006. Toggweiler, J. R. and Sarmiento, J. L.: Glacial to interglacial changes in atmospheric carbon dioxide: the critical role of ocean surface water in high latitudes, in: The Carbon Cycle and Atmospheric CO<sub>2</sub>: Natural Variations Archean to Present, Geophysical Monograph American Geophysical Union, 163–184, 1985. Tziperman, E. and Gildor, H.: On the mid-Pleistocene transition to 100-kyr glacial cycles and the asymmetry between glaciation and deglaciation times, Paleoceanography, 18(1), 1001, doi:10.1029/2001PA000627, 2003. Watson, A. J. and Naveira Garabato, A. C.: The role of Southern Ocean mixing and upwelling in glacial – interglacial atmospheric CO<sub>2</sub> change, Tellus, 58B(1), 73–87, 2006. Webb, D. J. and Suginohara, N.: Vertical mixing in the ocean, Nature, 409, p 37, 2001. Wunsch, C.: Determining paleoceanographic circulations, with emphasis on the Last Glacial Maximum, Quaternary Sci. Rev., 22, 371–385, 2003. Yu, J. and Elderfield, H.: Benthic foraminiferal B/Ca ratios reflect deep water carbonate saturation state, Earth Planet. Sci. Lett., 258, 73–86, 2007. Zeebe, R. E. and Wolf-Gladrow, D.: CO2 in seawater: Equilibrium, Kinetics, Isotopes, Elsevier, Amsterdam, The Netherlands, 2001.