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Localized subduction of anthropogenic carbon dioxide in the Southern Hemisphere oceans

Abstract

The oceans slow the rate of climate change by absorbing about 25% of anthropogenic carbon dioxide emissions annually. The Southern Ocean makes a substantial contribution to this oceanic carbon sink: more than 40% of the anthropogenic carbon dioxide in the ocean has entered south of 40° S. The rate-limiting step in the oceanic sequestration of anthropogenic carbon dioxide is the transfer of carbon across the base of the surface mixed layer into the ocean interior, a process known as subduction. However, the physical mechanisms responsible for the subduction of anthropogenic carbon dioxide are poorly understood. Here we use observationally based estimates of subduction and anthropogenic carbon concentrations in the Southern Ocean to determine the mechanisms responsible for carbon sequestration. We estimate that net subduction amounts to 0.42 ± 0.2 Pg C yr−1 between 35° S and the marginal sea-ice zone. We show that subduction occurs in specific locations as a result of the interplay of wind-driven Ekman transport, eddy fluxes and variations in mixed-layer depth. The zonal distribution of the estimated subduction is consistent with the distribution of anthropogenic carbon dioxide in the ocean interior. We conclude that oceanic carbon sequestration depends on physical properties, such as mixed-layer depth, ocean currents, wind and eddies, which are potentially sensitive to climate variability and change.

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Figure 1: Cant subduction into the ocean interior.
Figure 2: Cant inventory versus subduction pattern.
Figure 3: Vertical structure of Cant inventory at 30° S.

References

  1. Raupach, M., Marland, G. & Ciais, P. Global and regional drivers of accelerating CO2 emissions. Proc. Natl Acad. Sci. USA 104, 10288–10293 (2007).

    Article  Google Scholar 

  2. Le Quéré, C. et al. Trends in the sources and sinks of carbon dioxide. Nature Geosci. 2, 831–836 (2009).

    Article  Google Scholar 

  3. Doney, S. C., Lindsay, K., Caldeira, K. & Campin, J. Evaluating global ocean carbon models: The importance of realistic physics. Glob. Biogeochem. Cycles 18, GB3017 (2004).

    Article  Google Scholar 

  4. Matear, R. Effects of numerical advection schemes and eddy parameterizations on ocean ventilation and oceanic anthropogenic CO2 uptake. Ocean Model. 3, 217–248 (2001).

    Article  Google Scholar 

  5. Sarmiento, J. L., Orr, J. C. & Siegenthaler, U. A perturbation simulation of CO2 uptake in an Ocean General Circulation Model. J. Geophys. Res. 97, 3621–3645 (1992).

    Article  Google Scholar 

  6. Sabine, C. et al. The oceanic sink for anthropogenic CO2 . Science 305, 367–371 (2004).

    Article  Google Scholar 

  7. Ito, T., Woloszyn, M. & Mazloff, M. Anthropogenic carbon dioxide transport in the Southern Ocean driven by Ekman flow. Nature 463, 80–83 (2010).

    Article  Google Scholar 

  8. Mikaloff Fletcher, S. E. et al. Inverse estimates of anthropogenic CO2 uptake, transport, and storage by the ocean. Glob. Biogeochem. Cycles 20, GB2002 (2006).

    Article  Google Scholar 

  9. Khatiwala, S., Primeau, F. & Hall, T. Reconstruction of the history of anthropogenic CO2 concentrations in the ocean. Nature 462, 346–349 (2009).

    Article  Google Scholar 

  10. Rintoul, S., Hughes, C. & Olbers, D. The Antarctic circumpolar current system. Ocean, Circulation and Climate 271–302 (Academic, 2001).

    Google Scholar 

  11. McNeil, B., Tilbrook, B. & Matear, R. Accumulation and uptake of anthropogenic CO2 in the Southern Ocean, south of Australia between 1968 and 1996. J. Geophys. Res. 106, 31431–31445 (2001).

    Article  Google Scholar 

  12. Iudicone, D. et al. Watermasses as a unifying framework for understanding the Southern Ocean carbon cycle. Biogeosci. Discuss. 7, 3392–3451 (2010).

    Article  Google Scholar 

  13. Le Quéré, C. et al. Saturation of the Southern Ocean CO2 sink due to recent climate change. Science 316, 1735–1738 (2007).

    Article  Google Scholar 

  14. Lenton, A., Bopp, L. & Matear, R. Strategies for high-latitude northern hemisphere CO2 sampling now and in the future. Deep-Sea Res. 56, 523–532 (2009).

    Google Scholar 

  15. Lenton, A. & Matear, R. Role of the Southern Annular Mode (SAM) in Southern Ocean CO2 uptake. Glob. Biogeochem. Cycles 21, GB2016 (2007).

    Article  Google Scholar 

  16. McNeil, B., Tilbrook, B. & Matear, R. Seasonal varations in DIC and d13CDIC in the subantarctic zone, South of Australia Deep-Sea Res. (in the press).

  17. Sallée, J., Speer, K., Rintoul, S. & Wijffels, S. Southern Ocean thermocline ventilation. J. Phys. Ocean. 40, 509–529 (2010).

    Article  Google Scholar 

  18. Key, R., Kozyr, A., Sabine, C. & Lee, K. A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP). Glob. Biogeochem. Cycles 18, GB4031 (2004).

    Article  Google Scholar 

  19. Gruber, N., Sarmiento, J. L. & Stocker, T. F. An improved method for detecting anthropogenic CO2 in the oceans. Glob. Biogeochem. Cycles 10, 809–837 (1996).

    Article  Google Scholar 

  20. Matsumoto, K. & Gruber, N. How accurate is the estimation of anthropogenic carbon in the ocean? An evaluation of the DC* method. Glob. Biogeochem. Cycles 19, GB3014 (2005).

    Article  Google Scholar 

  21. Alvarez, M. et al. Estimating the storage of anthropogenic carbon in the subtropical Indian Ocean: A comparison of five different approaches—OceanRep. Biogeosciences 6, 681–703 (2009).

    Article  Google Scholar 

  22. Lo Monaco, C., Goyet, C., Metzl, N., Poisson, A. & Touratier, F. Distribution and inventory of anthropogenic CO2 in the Southern Ocean: Comparison of three data-based methods. J. Geophys. Res. 110, C09S02 (2005).

    Article  Google Scholar 

  23. Vázquez-Rodrı´guez, M. et al. Anthropogenic carbon distributions in the Atlantic Ocean: data-based estimates from the Arctic to the Antarctic. Biogeosciences 6, 439–451 (2009).

    Article  Google Scholar 

  24. Ito, T., Marshall, J. & Follows, M. What controls the uptake of transient tracers in the Southern Ocean. Glob. Biogeochem. Cycles 18, GB2021 (2004).

    Article  Google Scholar 

  25. Karleskind, P., Levy, M. & Mémery, L. Subduction of carbon, nitrogen, and oxygen in the northeast Atlantic. J. Geophys. Res. 116, C02025 (2011).

    Article  Google Scholar 

  26. Downes, S., Bindoff, N. & Rintoul, S. Impact of climate change on the subduction of mode and intermediate water masses in the Southern Ocean. J. Clim. 22, 3289–3302 (2009).

    Article  Google Scholar 

  27. Russell, J., Dixon, K., Gnanadesikan, A., Stouffer, R. & Toggweiler, J. The Southern Hemisphere westerlies in a warming world: Propping open the door to the deep ocean. J. Clim. 19, 6382–6390 (2006).

    Article  Google Scholar 

  28. Redi, M. Oceanic isopycnal mixing by coordinate rotation. J. Phys. Ocean. 12, 1154–1158 (1982).

    Article  Google Scholar 

  29. Solomon, H. On the representation of isentropic mixing in ocean circulation models. J. Phys. Ocean. 1, 233–234 (1971).

    Article  Google Scholar 

  30. Sallée, J., Speer, K., Morrow, R. & Lumpkin, R. An estimate of Lagrangian eddy statistics and diffusion in the mixed layer of the Southern Ocean. J. Marine Res. 66, 441–463 (2008).

    Article  Google Scholar 

  31. Cisewski, B., Strass, V. & Prandke, H. Upper-ocean vertical mixing in the Antarctic Polar Front Zone. Deep-Sea Res. 52, 1087–1108 (2005).

    Google Scholar 

  32. Sallée, J., Speer, K. & Morrow, R. Response of the Antarctic Circumpolar Current to atmospheric variability. J. Clim. 21, 3020–3039 (2008).

    Article  Google Scholar 

Download references

Acknowledgements

The comments from T. Ito on an earlier version of this manuscript and from N. Gruber have greatly improved this work. The authors would like to acknowledge the financial support of the CSIRO Wealth from Oceans National Research Flagship, the Australian Climate Change Science Programme and from the Australian Government’s Cooperative Research Centre programme through the Antarctic Climate and Ecosystems Cooperative Research Centre. J-B.S. started this work with the support of a CSIRO Office of the Chief Executive Postdoctoral Fellowship.

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J-B.S. directed the analysis of the several data sets used here and shared responsibility for writing the manuscript. R.J.M., S.R.R. and A.L. participated in the data analysis and shared responsibility for writing the manuscript. All authors contributed to the final version of the manuscript.

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Correspondence to Jean-Baptiste Sallée.

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The authors declare no competing financial interests.

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Sallée, JB., Matear, R., Rintoul, S. et al. Localized subduction of anthropogenic carbon dioxide in the Southern Hemisphere oceans. Nature Geosci 5, 579–584 (2012). https://doi.org/10.1038/ngeo1523

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