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Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release

Abstract

Radiocarbon in the atmosphere is regulated largely by ocean circulation, which controls the sequestration of carbon dioxide (CO2) in the deep sea through atmosphere–ocean carbon exchange. During the last glaciation, lower atmospheric CO2 levels were accompanied by increased atmospheric radiocarbon concentrations that have been attributed to greater storage of CO2 in a poorly ventilated abyssal ocean1,2. The end of the ice age was marked by a rapid increase in atmospheric CO2 concentrations2 that coincided with reduced 14C/12C ratios (Δ14C) in the atmosphere3, suggesting the release of very ‘old’ (14C-depleted) CO2 from the deep ocean to the atmosphere3. Here we present radiocarbon records of surface and intermediate-depth waters from two sediment cores in the southwest Pacific and Southern oceans. We find a steady 170 per mil decrease in Δ14C that precedes and roughly equals in magnitude the decrease in the atmospheric radiocarbon signal during the early stages of the glacial–interglacial climatic transition. The atmospheric decrease in the radiocarbon signal coincides with regionally intensified upwelling and marine biological productivity4, suggesting that CO2 released by means of deep water upwelling in the Southern Ocean lost most of its original depleted-14C imprint as a result of exchange and isotopic equilibration with the atmosphere. Our data imply that the deglacial 14C depletion previously identified in the eastern tropical North Pacific5 must have involved contributions from sources other than the previously suggested carbon release by way of a deep Southern Ocean pathway5, and may reflect the expanded influence of the 14C-depleted North Pacific carbon reservoir across this interval. Accordingly, shallow water masses advecting north across the South Pacific in the early deglaciation had little or no residual 14C-depleted signals owing to degassing of CO2 and biological uptake in the Southern Ocean.

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Figure 1: Ocean circulation in the South Pacific and Southern Ocean and ambient water-mass patterns at the location of the sediment cores used in this study.
Figure 2: Records of radiocarbon activities, Antarctic temperatures and Southern Ocean upwelling across the last deglaciation.
Figure 3: Records of atmospheric CO 2 , radiocarbon activities, and surface δ 13 C and productivity across the last deglaciation.

References

  1. Toggweiler, J. R. Variation of atmospheric CO2 by ventilation of the ocean’s deepest water. Paleoceanography 14, 571–588 (1999)

    Article  ADS  Google Scholar 

  2. Monnin, E. et al. Atmospheric CO2 concentrations over the last glacial termination. Science 291, 112–115 (2001)

    Article  CAS  ADS  Google Scholar 

  3. Broecker, W. & Barker, S. A 190‰ drop in atmosphere’s Δ14C during the “Mystery Interval” (17.5 to 14.5 kyr). Earth Planet. Sci. Lett. 256, 90–97 (2007)

    Article  CAS  ADS  Google Scholar 

  4. Anderson, R. F. et al. Wind-driven upwelling in the Southern Ocean and the deglacial rise in atmospheric CO2 . Science 323, 1441–1448 (2009)

    ADS  Google Scholar 

  5. Marchitto, T., Lehman, S. J., Ortiz, J. D., Flückiger, J. & van Geen, A. Marine radiocarbon evidence for the mechanism of deglacial atmospheric CO2 rise. Science 316, 1456–1459 (2007)

    Article  CAS  ADS  Google Scholar 

  6. Muscheler, R. et al. Changes in the carbon cycle during the last deglaciation as indicated by the comparison of 10Be and 14C records. Earth Planet. Sci. Lett. 219, 325–340 (2004)

    Article  CAS  ADS  Google Scholar 

  7. Hughen, K. A., Southen, J. R., Lehman, S. J., Bertrand, C. & Turnbull, J. Marine-derived 14C calibration and activity record for the past 50,000 years updated from the Cariaco Basin. Quat. Sci. Rev. 25, 3216–3227 (2006)

    Article  ADS  Google Scholar 

  8. Robinson, L. F. et al. Radiocarbon variability in the western North Atlantic during the last deglaciation. Science 310, 1469–1473 (2005)

    Article  CAS  ADS  Google Scholar 

  9. Keigwin, L. D. Radiocarbon and stable isotope constraints on Last Glacial Maximum and Younger Dryas ventilation in the western North Atlantic. Paleoceanography 19, PA4012 (2004)

    Article  ADS  Google Scholar 

  10. Galbraith, E. D. et al. Carbon dioxide release from the North Pacific abyss during the last deglaciation. Nature 449, 890–893 (2007)

    Article  CAS  ADS  Google Scholar 

  11. Sikes, E. L., Samson, C. R., Guilderson, T. P. & Howard, W. R. Old radiocarbon ages in the southwest Pacific Ocean during the last glacial period and deglaciation. Nature 405, 555–559 (2000)

    Article  CAS  ADS  Google Scholar 

  12. Broecker, W., Clark, E. & Barker, S. Near constancy of the Pacific Ocean surface to mid-depth radiocarbon-age difference over the last 20 kyr. Earth Planet. Sci. Lett. 274, 322–326 (2008)

    Article  CAS  ADS  Google Scholar 

  13. EPICA. One-to-one coupling of glacial climate variability in Greenland and Antarctica. Nature 444, 195–198 (2006)

  14. Toggweiler, J. R., Russell, J. L. & Carson, J. R. Mid-latitude westerlies, atmospheric CO2, and climate changes during the ice ages. Paleoceanography 21, PA2005 (2006)

    Article  ADS  Google Scholar 

  15. Hanawa, K. & Talley, L. D. in Ocean Circulation and Climate (eds Seidler, G., Church, J. & Gould, J.) 373–386 (Int. Geophys. Ser., Academic, 2001)

    Google Scholar 

  16. Bostok, H. C., Opdyke, B. N., Gagan, M. K. & Fifield, L. K. Carbon isotope evidence for changes in Antarctic Intermediate Water circulation and ocean ventilation in the southwest Pacific during the last deglaciation. Paleoceanography 19, PA4013 (2004)

    ADS  Google Scholar 

  17. Pahnke, K., Zahn, R., Elderfield, H. & Schulz, M. 340,000 year centennial scale marine record of southern hemispheric climate oscillation. Science 301, 948–952 (2003)

    Article  CAS  ADS  Google Scholar 

  18. Shane, P. A., Sikes, E. L. & Guilderson, T. P. Tephra beds in deep-sea cores off northern New Zealand: implications for the history of Taupo Volcanic Zone, Mayor Island, and White Island volcanoes. J. Volcanol. Geotherm. Res. 154, 276–290 (2006)

    Article  CAS  ADS  Google Scholar 

  19. Lowe, D. J., Shane, P. A. R., Alloway, B. V. & Newnham, R. W. Fingerprints and age models for widespread New Zealand tephra marker beds erupted since 30,000 yr ago as a framework for NZ-INTIMATE. Quat. Sci. Rev. 27, 95–126 (2008)

    Article  ADS  Google Scholar 

  20. Reimer, P. J. et al. IntCal04 terrestrial radiocarbon calibration, 0–26 cal kyr BP. Radiocarbon 46, 1029–1058 (2004)

    Article  CAS  Google Scholar 

  21. Key, R. M. et al. WOCE AMS radiocarbon I: Pacific Ocean results (P6, P16, and P17). Radiocarbon 38, 425–518 (1996)

    Article  CAS  Google Scholar 

  22. Bard, E. Correction of accelerator mass spectrometry 14C ages measured in planktonic foraminifera: paleoceanographic implications. Paleoceanography 3, 635–646 (1988)

    Article  ADS  Google Scholar 

  23. Pol-Holz, R. D., Keigwin, L., Southon, J., Hebbeln, D. & Mohtadi, M. No signature of abyssal carbon in intermediate waters off Chile during deglaciation. Nature Geosci. 3, 192–195 (2010)

    Article  ADS  Google Scholar 

  24. McManus, J. F., Francois, R., Gherardi, J. M., Keigwin, L. D. & Leger, S. B. Collapse and rapid resumption of Atlantic meridional circulation linked to deglacial climate changes. Nature 428, 834–837 (2004)

    Article  CAS  ADS  Google Scholar 

  25. Gnanadesikan, A., Russell, J. L. & Zeng, F. How does ocean ventilation change under global warming? Ocean Sci. 3, 43–53 (2007)

    Article  ADS  Google Scholar 

  26. Curry, W. B. & Oppo, D. Glacial water mass geometry and the distribution of δ13C of ΣCO2 in the Western Atlantic Ocean. Paleoceanography 20, PA1017 (2005)

    Article  ADS  Google Scholar 

  27. Gnanadesikan, A. A simple model for the structure of the oceanic pycnocline. Science 283, 2077–2079 (1999)

    Article  CAS  ADS  Google Scholar 

  28. Sarnthein, M., Grootes, P. M., Kennett, J. P. & Nadeau, M.-J. in Ocean Circulation: Mechanisms and Impacts (eds Schmittner, A., Chiang, J. C. H. & Hemmings, S. R.) 175–196 (Geophys. Monogr. Ser. 173, American Geophysical Union, 2007)

    Google Scholar 

  29. Pahnke, K. & Zahn, R. Southern hemisphere water mass conversion linked with North Atlantic climate variability. Science 307, 1741–1746 (2005)

    Article  CAS  ADS  Google Scholar 

  30. Spero, H. J. & Lea, D. W. The cause of carbon isotope minimum events on glacial terminations. Science 296, 522–525 (2002)

    Article  CAS  ADS  Google Scholar 

  31. Russell, J. L., Dixon, K. W., Gnanadesikan, A., Stouffer, R. J. & Toggweiler, J. R. Southern Ocean westerlies in a warming world: propping open the door to the deep ocean. J. Clim. 19, 6382–6390 (2006)

    Article  ADS  Google Scholar 

  32. Sachs, J. P. & Anderson, R. F. Increased productivity in the Subantarctic ocean during Heinrich events. Nature 434, 1118–1120 (2005)

    Article  CAS  ADS  Google Scholar 

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Acknowledgements

We thank the captain and crew of the RV Revelle, and our shipboard colleagues during the Zheng leg 3 (RR0503) cruise funded by the National Science Foundation (NSF), which collected the RR core. Core MD97-2120 was collected through the International Marine Past Global Change Study (IMAGES) program and with the technical support of the Institut Polaire Français Paul Emile Victor (IPEV) who made the research vessel Marion Dufresne available for core retrieval. H.J.S., E.L.S. and T.P.G., and the shore analyses, were supported by NSF awards and the Evolving Earth Foundation, and the Geological Society of America provided support for K.A.R. during her MSc. R.Z. acknowledges support from the MICINN, Spain. A portion of this work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory. We especially thank M. Cook for discussions, continuing input and suggestions throughout this study.

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Authors

Contributions

K.A.R. participated in the RR0503 cruise, sampled cores, prepared sediments, speciated foraminifera for isotopic and radiocarbon analyses, performed all stable isotopic analyses and prepared figures. E.L.S. led the RR0503 cruise, sampled cores, speciated foraminifera for isotopic and radiocarbon analyses, prepared figures and wrote the paper. T.P.G. participated in the RR0503 cruise and performed all radiocarbon analyses. P.S. participated in the RR0503 cruise and identified all tephras. H.J.S. designed the study and, with T.M.H., supervised KAR during her MSc. R.Z. provided the MD core samples and supplementary data for that core. All authors contributed to the interpretation of the results and provided input on the manuscript.

Corresponding author

Correspondence to Elisabeth L. Sikes.

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The authors declare no competing financial interests.

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This file contains Supplementary Methods and Data, Supplementary Figures 1 - 3 with legends, References and Supplementary Tables 1 - 4. (PDF 485 kb)

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Rose, K., Sikes, E., Guilderson, T. et al. Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release. Nature 466, 1093–1097 (2010). https://doi.org/10.1038/nature09288

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