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Calcium carbonate dissolution patterns in the ocean


Calcium carbonate (CaCO3) minerals secreted by marine organisms are abundant in the ocean. These particles settle and the majority dissolves in deeper waters or at the seafloor. Dissolution of carbonates buffers the ocean, but the vertical and regional distribution and magnitude of dissolution are unclear. Here we use seawater chemistry and age data to derive pelagic CaCO3 dissolution rates in major oceanic regions and provide the first data-based, regional profiles of CaCO3 settling fluxes. We find that global CaCO3 export at 300 m depth is 76 ± 12 Tmol yr−1, of which 36 ± 8 Tmol (47%) dissolves in the water column. Dissolution occurs in two distinct depth zones. In shallow waters, metabolic CO2 release and high-magnesium calcites dominate dissolution while increased CaCO3 solubility governs dissolution in deeper waters. Based on reconstructed sinking fluxes, our data indicate a higher CaCO3 transfer efficiency from the surface to the seafloor in high-productivity, upwelling areas than in oligotrophic systems. These results have implications for assessments of future ocean acidification as well as palaeorecord interpretations, as they demonstrate that surface ecosystems, not only interior ocean chemistry, are key to controlling the dissolution of settling CaCO3 particles.

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Fig. 1: Conceptual view of the oceanic CaCO3 cycle.
Fig. 2: Regional profiles of reconstructed CaCO3 dissolution rates and saturation horizons.
Fig. 3: Reconstructed regional CaCO3 settling fluxes and depth distributions of their sinks.
Fig. 4: Global CaCO3 settling flux profile and depth distribution of its sinks.

Data availability

The TTD ages85 are made available as GLODAPv2 affiliated data on the NOAA Ocean Carbon Data System website at Seawater chemistry data are available from the GLODAPv2.2016 in refs. 58,59, sediment-trap data are available from ref. 83, 14C-derived ages are available from ref. 71, biome distributions are available from ref. 74 and sediment fluxes are available from refs. 18,39,40.

Code availability

The MATLAB script to reproduce the regional CaCO3 dissolution rate and reconstructed settling fluxes is available at


  1. Richardson, T. L. Mechanisms and pathways of small-phytoplankton export from the surface ocean. Annu. Rev. Mar. Sci. 11, 57–74 (2019).

    Article  Google Scholar 

  2. Silver, M. W., Shanks, A. L. & Trent, J. D. Marine snow: microplankton habitat and source of small-scale patchiness in pelagic populations. Science 201, 371–373 (1978).

    Article  Google Scholar 

  3. Archer, D. et al. Atmospheric lifetime of fossil fuel carbon dioxide. Annu. Rev. Earth Planet. Sci. 37, 117–134 (2009).

    Article  Google Scholar 

  4. Woosley, R. J., Millero, F. J. & Grosell, M. The solubility of fish-produced high magnesium calcite in seawater. J. Geophys. Res. Oceans 117, C04018 (2012).

    Article  Google Scholar 

  5. Chave, K. E. Aspects of the biogeochemistry of magnesium 1. Calcareous marine organisms. J. Geol. 62, 266–283 (1954).

    Article  Google Scholar 

  6. Wilson, R. W. et al. Contribution of fish to the marine inorganic carbon cycle. Science 323, 359–362 (2009).

    Article  Google Scholar 

  7. Berner, R. A., Berner, E. K. & Keir, R. S. Aragonite dissolution on the Bermuda Pedestal: its depth and geochemical significance. Earth Planet. Sci. Lett. 30, 169–178 (1976).

    Article  Google Scholar 

  8. Agegian, C. R., Mackenzie, F. T., Tribble, J. S. & Sabine, C. L. in Biogeochemical Cycling and Fluxes Between the Deep Euphotic Zone and Other Oceanic Realms (ed. Agegian, C. R.) 5–32 (Undersea Research Program, National Oceanic and Atmospheric Administration, 1988).

  9. Buitenhuis, E. T., Le Quéré, C., Bednaršek, N. & Schiebel, R. Large contribution of pteropods to shallow CaCO3 export. Glob. Biogeochem. Cycles 33, 458–468 (2019).

    Article  Google Scholar 

  10. Gangstø, R. et al. Modeling the marine aragonite cycle: changes under rising carbon dioxide and its role in shallow water CaCO3 dissolution. Biogeosciences 5, 1057–1072 (2008).

    Article  Google Scholar 

  11. Morse, J. W., Andersson, A. J. & Mackenzie, F. T. Initial responses of carbonate-rich shelf sediments to rising atmospheric pCO2 and “ocean acidification”: role of high Mg-calcites. Geochim. Cosmochim. Acta 70, 5814–5830 (2006).

    Article  Google Scholar 

  12. Buesseler, K. O. et al. An assessment of the use of sediment traps for estimating upper ocean particle fluxes. J. Mar. Res. 65, 345–416 (2007).

    Article  Google Scholar 

  13. Dunne, J. P., Sarmiento, J. L. & Gnanadesikan, A. A synthesis of global particle export from the surface ocean and cycling through the ocean interior and on the seafloor. Glob. Biogeochem. Cycles (2007).

  14. Milliman, J. D. Production and accumulation of calcium carbonate in the ocean: budget of a nonsteady state. Glob. Biogeochem. Cycles 7, 927–957 (1993).

    Article  Google Scholar 

  15. Berelson, W. M. et al. Relating estimates of CaCO3 production, export, and dissolution in the water column to measurements of CaCO3 rain into sediment traps and dissolution on the sea floor: a revised global carbonate budget. Glob. Biogeochem. Cycles (2007).

  16. Smith, S. V. & Mackenzie, F. T. The role of CaCO3 reactions in the contemporary oceanic CO2 cycle. Aquat. Geochem. (2016).

  17. Battaglia, G., Steinacher, M. & Joos, F. A probabilistic assessment of calcium carbonate export and dissolution in the modern ocean. Biogeosciences 13, 2823–2848 (2016).

    Article  Google Scholar 

  18. Sulpis, O. et al. Current CaCO3 dissolution at the seafloor caused by anthropogenic CO2. Proc. Natl Acad. Sci. USA 115, 11700–11705 (2018).

    Article  Google Scholar 

  19. Mucci, A. The solubility of calcite and aragonite in seawater at various salinities, temperatures and one atmosphere total pressure. Am. J. Sci. 283, 780–799 (1983).

    Article  Google Scholar 

  20. Hoegh-Guldberg, O. et al. Coral reefs under rapid climate change and ocean acidification. Science 318, 1737–1742 (2007).

    Article  Google Scholar 

  21. Peterson, M. N. A. Calcite: rates of dissolution in a vertical profile in the Central Pacific. Science 154, 1542–1544 (1966).

    Article  Google Scholar 

  22. Berger, W. H. Foraminiferal ooze: solution at depths. Science 156, 383–385 (1967).

    Article  Google Scholar 

  23. Millero, F. J. The thermodynamics of the carbonic acid system in seawater. Geochim. Cosmochim. Acta 43, 1651–1661 (1979).

    Article  Google Scholar 

  24. Morse, J. W. & Mackenzie, F. T. Geochemistry of Sedimentary Carbonates (Elsevier, 1990).

  25. Dong, S. et al. Aragonite dissolution kinetics and calcite/aragonite ratios in sinking and suspended particles in the North Pacific. Earth Planet. Sci. Lett. 515, 1–12 (2019).

    Article  Google Scholar 

  26. Honjo, S. & Erez, J. Dissolution rates of calcium carbonate in the deep ocean; an in-situ experiment in the North Atlantic Ocean. Earth Planet. Sci. Lett. 40, 287–300 (1978).

    Article  Google Scholar 

  27. White, M. M. et al. Coccolith dissolution within copepod guts affects fecal pellet density and sinking rate. Sci. Rep. 8, 9758 (2018).

    Article  Google Scholar 

  28. Oakes, R. L., Peck, V. L., Manno, C. & Bralower, T. J. Degradation of internal organic matter is the main control on pteropod shell dissolution after death. Glob. Biogeochem. Cycles 33, 749–760 (2019).

    Article  Google Scholar 

  29. Feely, R. A. et al. In situ calcium carbonate dissolution in the Pacific Ocean. Glob. Biogeochem. Cycles (2002).

  30. Sabine, C. L., Key, R. M., Feely, R. A. & Greeley, D. Inorganic carbon in the Indian Ocean: distribution and dissolution processes. Glob. Biogeochem. Cycles 16, 15-11–15-18 (2002).

    Article  Google Scholar 

  31. Chung, S. N. et al. Calcium carbonate budget in the Atlantic Ocean based on water column inorganic carbon chemistry. Glob. Biogeochem. Cycles (2003).

  32. Feely, R. A. et al. Impact of anthropogenic CO2 on the CaCO3 system in the oceans. Science 305, 362–366 (2004).

    Article  Google Scholar 

  33. Rosón, G., Guallart, E. F., Pérez, F. F. & Ríos, A. F. Calcium distribution in the subtropical Atlantic Ocean: implications for calcium excess and saturation horizons. J. Mar. Syst. 158, 45–51 (2016).

    Article  Google Scholar 

  34. Andruleit, H. A. Dissolution-affected coccolithophore fluxes in the central Greenland Sea (1994/1995). Deep Sea Res. II 47, 1719–1742 (2000).

    Article  Google Scholar 

  35. Troy, P. J., Li, Y.-H. & Mackenzie, F. T. Changes in surface morphology of calcite exposed to the oceanic water column. Aquat. Geochem. 3, 1–20 (1997).

    Article  Google Scholar 

  36. Betzer, P. R. et al. The oceanic carbonate system: a reassessment of biogenic controls. Science 226, 1074–1077 (1984).

    Article  Google Scholar 

  37. Broecker, W. S. & Peng, T. H. Tracers in the Sea (Lamont-Doherty Geological Observatory, 1982).

  38. Friis, K., Najjar, R. G., Follows, M. J. & Dutkiewicz, S. Possible overestimation of shallow-depth calcium carbonate dissolution in the ocean. Glob. Biogeochem. Cycles (2006).

  39. Jahnke, R. A. The global ocean flux of particulate organic carbon: areal distribution and magnitude. Glob. Biogeochem. Cycles 10, 71–88 (1996).

    Article  Google Scholar 

  40. Jenkins, C. J. Building offshore soils databases. Sea Technol. 38, 25–28 (1997).

    Google Scholar 

  41. Honjo, S. Coccoliths: production, transportation and sedimentation. Mar. Micropaleontol. 1, 65–79 (1976).

    Article  Google Scholar 

  42. Subhas, A. V. et al. The dissolution behavior of biogenic calcites in seawater and a possible role for magnesium and organic carbon. Mar. Chem. 205, 100–112 (2018).

    Article  Google Scholar 

  43. Byrne, R. H., Acker, J. G., Betzer, P. R., Feely, R. A. & Cates, M. H. Water column dissolution of aragonite in the Pacific Ocean. Nature 312, 321–326 (1984).

    Article  Google Scholar 

  44. Boeuf, D. et al. Biological composition and microbial dynamics of sinking particulate organic matter at abyssal depths in the oligotrophic open ocean. Proc. Natl Acad. Sci. USA 116, 11824–11832 (2019).

    Article  Google Scholar 

  45. Haine, T. W. N. & Hall, T. M. A generalized transport theory: water-mass composition and age. J. Phys. Oceanogr. 32 (2002).

  46. Bednaršek, N., Možina, J., Vogt, M., O’Brien, C. & Tarling, G. A. The global distribution of pteropods and their contribution to carbonate and carbon biomass in the modern ocean. Earth Syst. Sci. Data 4, 167–186 (2012).

    Article  Google Scholar 

  47. De La Rocha, C. L. & Passow, U. Factors influencing the sinking of POC and the efficiency of the biological carbon pump. Deep Sea Res. II 54, 639–658 (2007).

    Article  Google Scholar 

  48. Gehlen, M. et al. The fate of pelagic CaCO3 production in a high CO2 ocean: a model study. Biogeosciences 4, 505–519 (2007).

    Article  Google Scholar 

  49. Middelburg, J. J., Soetaert, K. & Hagens, M. Ocean alkalinity, buffering and biogeochemical processes. Rev. Geophys. (2020).

  50. Boucher, O., Denvil, S., Caubel, A. & Foujols, M. A. IPSL-CM6A-LR Model Output Prepared for CMIP6 CMIP Version 20200710 (Earth System Grid Federation, 2018);

  51. Boucher, O. et al. Presentation and evaluation of the IPSL‐CM6A‐LR climate model. J. Adv. Model. Earth Syst. (2020).

  52. Aumont, O., Ethé, C., Tagliabue, A., Bopp, L. & Gehlen, M. PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies. Geosci. Model Dev. 8, 2465–2513 (2015).

    Article  Google Scholar 

  53. Perez, F. F. et al. Meridional overturning circulation conveys fast acidification to the deep Atlantic Ocean. Nature 554, 515–518 (2018).

    Article  Google Scholar 

  54. Orr, J. C. et al. Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437, 681–686 (2005).

    Article  Google Scholar 

  55. Archer, D. Modeling the calcite lysocline. J. Geophys. Res. (1991).

  56. Carter, B. R., Toggweiler, J. R., Key, R. M. & Sarmiento, J. L. Processes determining the marine alkalinity and calcium carbonate saturation state distributions. Biogeosciences 11, 7349–7362 (2014).

    Article  Google Scholar 

  57. Brewer, P. G., Wong, G. T. F., Bacon, M. P. & Spencer, D. W. An oceanic calcium problem? Earth Planet. Sci. Lett. 26, 81–87 (1975).

    Article  Google Scholar 

  58. Key, R. M. et al. Global Ocean Data Analysis Project Version 2 (GLODAPv2), ORNL/CDIAC-162, NDP-P093 (DOE, 2015).

  59. Olsen, A. et al. The Global Ocean Data Analysis Project version 2 (GLODAPv2)—an internally consistent data product for the world ocean. Earth Syst. Sci. Data 8, 297–323 (2016).

    Article  Google Scholar 

  60. Kanamori, S. & Ikegami, H. Calcium-alkalinity relationship in the North Pacific. J. Oceanogr. Soc. Jpn 38, 57–62 (1982).

    Article  Google Scholar 

  61. MS Excel Program Developed for CO2 System Calculations (ORNL/CDIAC-105a) (DOE, 2006).

  62. van Heuven, S., Pierrot, D., Rae, J. W. B., Lewis, E. & Wallace, D. W. R. MATLAB Program Developed for CO2 System Calculations (ORNL/CDIAC-105b) (DOE, 2011);

  63. Lueker, T. J., Dickson, A. G. & Keeling, C. D. Ocean pCO2 calculated from dissolved inorganic carbon, alkalinity, and equations for K1 and K2: validation based on laboratory measurements of CO2 in gas and seawater at equilibrium. Mar. Chem. 70, 105–119 (2000).

    Article  Google Scholar 

  64. Dickson, A. G. Standard potential of the reaction: AgCl(s) + 1/2H2(g) = Ag(s) + HCl(aq), and the standard acidity constant of the ion HSO4 in synthetic seawater from 273.15 to 318.15 K. J. Chem. Thermodyn. 22, 113–127 (1990).

    Article  Google Scholar 

  65. Dickson, A. G. & Riley, J. P. The estimation of acid dissociation constants in seawater media from potentionmetric titrations with strong base. I. The ionic product of water—Kw. Mar. Chem. 7, 89–99 (1979).

    Article  Google Scholar 

  66. Uppström, L. R. The boron/chlorinity ratio of deep-sea water from the Pacific Ocean. Deep Sea Res. Oceanogr. Abstr. 21, 161–162 (1974).

    Article  Google Scholar 

  67. Dickson, A. G. Thermodynamics of the dissociation of boric acid in synthetic seawater from 273.15 to 318.15 K. Deep Sea Res. A 37, 755–766 (1990).

    Article  Google Scholar 

  68. Waugh, D. W., Haine, T. W. N. & Hall, T. M. Transport times and anthropogenic carbon in the subpolar North Atlantic Ocean. Deep Sea Res. I 51, 1475–1491 (2004).

    Article  Google Scholar 

  69. Waugh, D. W., Hall, T. M., McNeil, B. I., Key, R. & Matear, R. J. Anthropogenic CO2 in the oceans estimated using transit time distributions. Tellus B 58, 376–389 (2006).

    Article  Google Scholar 

  70. Stöven, T., Tanhua, T., Hoppema, M. & Bullister, J. L. Perspectives of transient tracer applications and limiting cases. Ocean Sci. 11, 699–718 (2015).

    Article  Google Scholar 

  71. Gebbie, G. & Huybers, P. The mean age of ocean waters inferred from radiocarbon observations: sensitivity to surface sources and accounting for mixing histories. J. Phys. Oceanogr. 42, 291–305 (2012).

    Article  Google Scholar 

  72. Key, R. M. et al. A global ocean carbon climatology: results from Global Data Analysis Project (GLODAP). Glob. Biogeochem. Cycles (2004).

  73. He, Y.-C. et al. A model-based evaluation of the inverse Gaussian transit-time distribution method for inferring anthropogenic carbon storage in the ocean. J. Geophys. Res. Oceans 123, 1777–1800 (2018).

    Article  Google Scholar 

  74. Fay, A. R. & McKinley, G. A. Global open-ocean biomes: mean and temporal variability. Earth Syst. Sci. Data 6, 273–284 (2014).

    Article  Google Scholar 

  75. De Boor, C. A Practical Guide to Splines Vol. 27 (Springer-Verlag, 1978).

  76. Goff, J. A., Jenkins, C. J. & Williams, S. J. Seabed mapping and characterization of sediment variability using the usSEABED data base. Cont. Shelf Res. 28, 614–633 (2008).

    Article  Google Scholar 

  77. Hemleben, C., Spindler, M. & Anderson, O. R. Modern Planktonic Foraminifera (Springer-Verlag, 1989).

  78. Noji, T. T. et al. Clearance of picoplankton-sized partides and formation of rapidly sinking aggregates by the pteropod, Limacina reiroversa. J. Plankton Res. 19, 863–875 (1997).

    Article  Google Scholar 

  79. Berelson, W. M. Particle settling rates increase with depth in the ocean. Deep Sea Res. II 49, 237–251 (2001).

    Article  Google Scholar 

  80. Weber, T., Cram, J. A., Leung, S. W., DeVries, T. & Deutsch, C. Deep ocean nutrients imply large latitudinal variation in particle transfer efficiency. Proc. Natl Acad. Sci. USA 113, 8606–8611 (2016).

    Article  Google Scholar 

  81. Morel, A. et al. Examining the consistency of products derived from various ocean color sensors in open ocean (Case 1) waters in the perspective of a multi-sensor approach. Remote Sens. Environ. 111, 69–88 (2007).

    Article  Google Scholar 

  82. Buesseler, K. O., Boyd, P. W., Black, E. E. & Siegel, D. A. Metrics that matter for assessing the ocean biological carbon pump. Proc. Natl Acad. Sci. USA 117, 9679–9687 (2020).

    Article  Google Scholar 

  83. Mouw, C. B., Barnett, A., McKinley, G. A., Gloege, L. & Pilcher, D. Global ocean particulate organic carbon flux merged with satellite parameters. Earth Syst. Sci. Data 8, 531–541 (2016).

    Article  Google Scholar 

  84. Riley, J. P. & Tongudai, M. The major cation/chlorinity ratios in sea water. Chem. Geol. 2, 263–269 (1967).

    Article  Google Scholar 

  85. Jeansson, E., Steinfeldt, R. & Tanhua, T. Water Mass Ages Based On GLODAPv2 Data Product (NCEI Accession 0226793) (NOAA, National Centers for Environmental Information, 2021).

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We thank G. Gebbie for providing the seawater 14C-age dataset. We thank all who contributed to the creation of GLODAPv2. We thank M. P. Humphreys, W. M. Berelson, S. Dong and A. V. Subhas for useful comments on an earlier version of the manuscript and the three journal reviewers for constructive feedback. O.S. and J.J.M. were supported by the Dutch Ministry of Education via the Netherlands Earth System Science Centre (NESSC). A.D. was supported by the Swiss National Science Foundation (#200020_172476) and by the UniBE international 2021 fellowship programme of the University of Bern.

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Authors and Affiliations



O.S. and J.J.M. designed the research. O.S. performed the data analysis with inputs from A.D. and wrote the manuscript with contributions from all authors. E.J. and S.K.L. contributed the TTD-age analysis and advised on its usage. All authors interpreted the results and edited the manuscript.

Corresponding author

Correspondence to Olivier Sulpis.

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The authors declare no competing interests.

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Peer review information Nature Geoscience thanks Andreas Andersson, Kai Schulz and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Xujia Jiang.

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Extended data

Extended Data Fig. 1 Depth-latitude distributions of seawater properties in the Atlantic Ocean.

a, Seawater Alk*, b, seawater age and c, potential density (σ0) are shown in depth-latitude diagrams separated according to three biogeochemically-distinct regions on which we base our analysis, corresponding to the (left) subtropical South Atlantic, (center) Equatorial Atlantic and (right) subtropical Noth Atlantic regions shown in Extended Data Fig. 2.

Extended Data Fig. 2 Oceanic regions.

Geographical boundaries of the 10 regions used for our study. Black dots correspond to the locations of GLODAPv2 seawater chemistry and age data. Green stars correspond to the locations of sediment-trap data. The numbers indicate the 10 regions: 1, subpolar North Pacific, 2, subtropical North Pacific, 3, Equatorial Pacific, 4, subtropical South Pacific, 5, subpolar North Atlantic, 6, subtropical North Atlantic, 7, Equatorial Atlantic, 8, subtropical South Atlantic, 9, Indian Ocean and 10, Southern Ocean. Polar regions are in blue, subtropical regions are in yellow and equatorial regions are in orange.

Extended Data Fig. 3 Alk* versus seawater age plots from the Atlantic Ocean.

Plots corresponding to randomly selected density bins from the Suptropical North Atlantic (a,d,g), Equatorial Atlantic (b,e,h) and Subtropical South Atlantic (c,f,i). The spatial distribution of the Alk* and seawater age data is shown in Extended Data Fig. 1. Red lines are linear fits from which CaCO3 dissolution rates are estimated, computed as half of the slope, expressed in μmol kg−1 a−1. For each regional density, the mean depth (± 1σ) and the σ0 range are reported.

Extended Data Fig. 4 CaCO3 dissolution rate profiles from the Atlantic Ocean.

Black points correspond to discrete CaCO3 dissolution rate estimates computed as shown in Extended Data Fig. 3, using a constant sigma increment (σ0 = 0.01). Yellow stars represent the 9 CaCO3 dissolution rate estimates originating from Extended Data Fig. 3. Red lines are cubic smoothing splines used to interpolate discrete dissolution rate estimates over depth and obtain regionally harmonized depth profiles.

Extended Data Fig. 5 CaCO3 burial and dissolution rates at the seafloor.

The sum of (a) the burial rate at the seafloor and (b) the dissolution rate at the sediment-water interface represents the CaCO3 flux reaching the seafloor. The three Atlantic regions on which the Methods section focuses are contoured in a black thick line.

Extended Data Fig. 6 Atlantic seafloor CaCO3 sinks and reconstructed settling fluxes.

In each panel, the orange dashed line represents the CaCO3 dissolution rate at the sediment-water interface depth profile (from Extended Data Fig. 5a), the grey dashed line represents the CaCO3 burial rate in sediments (from Extended Data Fig. 5b), the solid black line is the sum of seafloor dissolution and burial at each depth and the solid turquoise line is the reconstructed CaCO3 settling flux.

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Sulpis, O., Jeansson, E., Dinauer, A. et al. Calcium carbonate dissolution patterns in the ocean. Nat. Geosci. 14, 423–428 (2021).

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