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.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Raupach, M., Marland, G. & Ciais, P. Global and regional drivers of accelerating CO2 emissions. Proc. Natl Acad. Sci. USA 104, 10288–10293 (2007).
Le Quéré, C. et al. Trends in the sources and sinks of carbon dioxide. Nature Geosci. 2, 831–836 (2009).
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).
Matear, R. Effects of numerical advection schemes and eddy parameterizations on ocean ventilation and oceanic anthropogenic CO2 uptake. Ocean Model. 3, 217–248 (2001).
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).
Sabine, C. et al. The oceanic sink for anthropogenic CO2 . Science 305, 367–371 (2004).
Ito, T., Woloszyn, M. & Mazloff, M. Anthropogenic carbon dioxide transport in the Southern Ocean driven by Ekman flow. Nature 463, 80–83 (2010).
Mikaloff Fletcher, S. E. et al. Inverse estimates of anthropogenic CO2 uptake, transport, and storage by the ocean. Glob. Biogeochem. Cycles 20, GB2002 (2006).
Khatiwala, S., Primeau, F. & Hall, T. Reconstruction of the history of anthropogenic CO2 concentrations in the ocean. Nature 462, 346–349 (2009).
Rintoul, S., Hughes, C. & Olbers, D. The Antarctic circumpolar current system. Ocean, Circulation and Climate 271–302 (Academic, 2001).
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).
Iudicone, D. et al. Watermasses as a unifying framework for understanding the Southern Ocean carbon cycle. Biogeosci. Discuss. 7, 3392–3451 (2010).
Le Quéré, C. et al. Saturation of the Southern Ocean CO2 sink due to recent climate change. Science 316, 1735–1738 (2007).
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).
Lenton, A. & Matear, R. Role of the Southern Annular Mode (SAM) in Southern Ocean CO2 uptake. Glob. Biogeochem. Cycles 21, GB2016 (2007).
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).
Sallée, J., Speer, K., Rintoul, S. & Wijffels, S. Southern Ocean thermocline ventilation. J. Phys. Ocean. 40, 509–529 (2010).
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).
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).
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).
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).
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).
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).
Ito, T., Marshall, J. & Follows, M. What controls the uptake of transient tracers in the Southern Ocean. Glob. Biogeochem. Cycles 18, GB2021 (2004).
Karleskind, P., Levy, M. & Mémery, L. Subduction of carbon, nitrogen, and oxygen in the northeast Atlantic. J. Geophys. Res. 116, C02025 (2011).
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).
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).
Redi, M. Oceanic isopycnal mixing by coordinate rotation. J. Phys. Ocean. 12, 1154–1158 (1982).
Solomon, H. On the representation of isentropic mixing in ocean circulation models. J. Phys. Ocean. 1, 233–234 (1971).
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).
Cisewski, B., Strass, V. & Prandke, H. Upper-ocean vertical mixing in the Antarctic Polar Front Zone. Deep-Sea Res. 52, 1087–1108 (2005).
Sallée, J., Speer, K. & Morrow, R. Response of the Antarctic Circumpolar Current to atmospheric variability. J. Clim. 21, 3020–3039 (2008).
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.
Author information
Authors and Affiliations
Contributions
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.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary Information
Supplementary Information (PDF 849 kb)
Rights and permissions
About this article
Cite this article
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
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/ngeo1523
This article is cited by
-
Contemporary oceanic radiocarbon response to ocean circulation changes
Climate Dynamics (2023)
-
Long-term evolution of ocean eddy activity in a warming world
Nature Climate Change (2022)
-
Stratification constrains future heat and carbon uptake in the Southern Ocean between 30°S and 55°S
Nature Communications (2022)
-
Modeling the mixed layer depth in Southern Ocean using high resolution regional coupled ocean sea ice model
Modeling Earth Systems and Environment (2022)
-
A review of the scientific knowledge of the seascape off Dronning Maud Land, Antarctica
Polar Biology (2022)