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Reversed flow of Atlantic deep water during the Last Glacial Maximum


The meridional overturning circulation (MOC) of the Atlantic Ocean is considered to be one of the most important components of the climate system. This is because its warm surface currents, such as the Gulf Stream, redistribute huge amounts of energy from tropical to high latitudes and influence regional weather and climate patterns, whereas its lower limb ventilates the deep ocean and affects the storage of carbon in the abyss, away from the atmosphere. Despite its significance for future climate, the operation of the MOC under contrasting climates of the past remains controversial. Nutrient-based proxies1,2 and recent model simulations3 indicate that during the Last Glacial Maximum the convective activity in the North Atlantic Ocean was much weaker than at present. In contrast, rate-sensitive radiogenic 231Pa/230Th isotope ratios from the North Atlantic have been interpreted to indicate only minor changes in MOC strength4,5,6. Here we show that the basin-scale abyssal circulation of the Atlantic Ocean was probably reversed during the Last Glacial Maximum and was dominated by northward water flow from the Southern Ocean. These conclusions are based on new high-resolution data from the South Atlantic Ocean that establish the basin-scale north to south gradient in 231Pa/230Th, and thus the direction of the deep ocean circulation. Our findings are consistent with nutrient-based proxies and argue that further analysis of 231Pa/230Th outside the North Atlantic basin will enhance our understanding of past ocean circulation, provided that spatial gradients are carefully considered. This broader perspective suggests that the modern pattern of the Atlantic MOC—with a prominent southerly flow of deep waters originating in the North Atlantic—arose only during the Holocene epoch.

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Figure 1: Multi-proxy profiles of MD02-2594.
Figure 2: MD02-2594 versus North Atlantic records.
Figure 3: Transit time estimates.


  1. Curry, W. B. & Oppo, D. W. Glacial water mass geometry and the distribution of δ13C of ΣCO2 in the western Atlantic Ocean. Paleoceanography 20 PA1017 10.1029/2004PA001021 (2005)

    Article  ADS  Google Scholar 

  2. Marchitto, T. M. & Broecker, W. S. Deep water mass geometry in the glacial Atlantic ocean: a review of constraints from the paleonutrient proxy Cd/Ca. Geochem. Geophys. Geosyst. 7 Q12003 10.1029/2006GC001323 (2006)

    Article  ADS  CAS  Google Scholar 

  3. Liu, Z., Shin, S., Webb, R. S., Lewis, W. & Otto-Bliesner, B. L. Atmospheric CO2 forcing on glacial thermohaline circulation and climate. Geophys. Res. Lett. 32 L02706 10.1029/2004GL021929 (2005)

    Article  ADS  Google Scholar 

  4. Yu, E. F., François, R. & Bacon, M. P. Similar rates of modern and last-glacial ocean thermohaline circulation inferred from radiochemical data. Nature 379, 689–694 (1996)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  6. Roberts, N. L., Piotrowski, A. M., McManus, J. F. & Keigwin, L. D. Synchronous deglacial overturning and water mass source changes. Science 327, 75–78 (2010)

    Article  ADS  CAS  Google Scholar 

  7. Lynch-Stieglitz, J. et al. Atlantic meridional overturning circulation during the Last Glacial Maximum. Science 316, 66–69 (2007)

    Article  ADS  CAS  Google Scholar 

  8. Adkins, J. F., McIntyre, K. & Schrag, D. P. The salinity, temperature, and δ18O of the glacial deep ocean. Science 298, 1769–1773 (2002)

    Article  ADS  CAS  Google Scholar 

  9. Henderson, G. M. & Anderson, R. F. The U-series toolbox for paleoceanography. Rev. Mineral. Geochem. 52, 493–531 (2003)

    Article  CAS  Google Scholar 

  10. Marchal, O., Francois, R., Stocker, T. F. & Joos, F. Ocean thermohaline circulation and sedimentary 231Pa/230Th ratio. Paleoceanography 15, 625–641 (2000)

    Article  ADS  Google Scholar 

  11. Gherardi, J.-M. et al. Evidence from the Northeastern Atlantic basin for variability in the rate of the meridional overturning circulation through the last deglaciation. Earth Planet. Sci. Lett. 240, 710–723 (2005)

    Article  ADS  CAS  Google Scholar 

  12. Hall, I. R. et al. Accelerated drawdown of meridional overturning in the late-glacial Atlantic triggered by transient pre-H event freshwater perturbation. Geophys. Res. Lett. 33 10.1029/2006GL026239 (2006)

  13. Gherardi, J.-M. et al. Glacial-interglacial circulation changes inferred from 231Pa/230Th sedimentary record in the North Atlantic region. Paleoceanography 24 PA2204 10.1029/2008PA001696 (2009)

    Article  ADS  Google Scholar 

  14. McCave, I. N., Manighetti, B. & Robinson, S. G. Sortable silt and fine sediment size/composition slicing: parameters for paleocurrent speed and palaeoceanography. Paleoceanography 10, 593–610 (1995)

    Article  ADS  Google Scholar 

  15. Chase, Z., Anderson, R. F., Fleisher, M. Q. & Kubik, P. W. The influence of particle composition and particle flux on scavenging of Th, Pa and Be in the ocean. Earth Planet. Sci. Lett. 204, 215–229 (2002)

    Article  ADS  CAS  Google Scholar 

  16. Siddall, M. et al. 231Pa/230Th fractionation by ocean transport, biogenic particle flux and particle type. Earth Planet. Sci. Lett. 237, 135–155 (2005)

    Article  ADS  CAS  Google Scholar 

  17. Thomas, A. L., Henderson, G. M. & McCave, I. N. Constant bottom water flow into the Indian Ocean for the past 140 ka indicated by sediment 231Pa/230Th ratios. Paleoceanography 22 PA4210 10.1029/2007PA001415 (2007)

    Article  ADS  Google Scholar 

  18. Bradtmiller, L. I., Anderson, R. F., Fleisher, M. Q. & Burckle, L. H. Opal burial in the equatorial Atlantic Ocean over the last 30 ka: implications for glacial-interglacial changes in the ocean silicon cycle. Paleoceanography 22 PA4216 10.1029/2007PA001443 (2007)

    Article  ADS  Google Scholar 

  19. Huhn, O., Roether, W. & Steinfeldt, R. Age spectra in North Atlantic Deep Water along the South American continental slope, 10°N-30°S, based on tracer observations. Deep Sea Res. I 55, 1252–1276 (2008)

    Article  CAS  Google Scholar 

  20. Walter, H.-J., Rutgers van der Loeff, M. M. & Hoeltzen, H. Enhanced scavenging of 231Pa relative to 230Th in the South Atlantic south of the Polar Front: Implications for the use of the 231Pa/230Th ratio as a paleoproductivity proxy. Earth Planet. Sci. Lett. 149, 85–100 (1997)

    Article  ADS  CAS  Google Scholar 

  21. Thomas, A. L., Henderson, G. M. & Robinson, L. F. Interpretation of the 231Pa/230Th paleo circulation proxy: new water-column measurements from the southwest Indian Ocean. Earth Planet. Sci. Lett. 241, 493–504 (2006)

    Article  ADS  CAS  Google Scholar 

  22. Liu, Z. et al. Transient simulation of Last Deglaciation with a new mechanism for Bølling-Allerød warming. Science 325, 310–314 (2009)

    Article  ADS  CAS  Google Scholar 

  23. Keigwin, L. D. & Boyle, E. A. Did North Atlantic overturning halt 17,000 years ago? Paleoceanography 23 PA1101 10.1029/2007PA001500 (2008)

    Article  ADS  Google Scholar 

  24. Lippold, J. et al. Does sedimentary 231Pa/230Th from the Bermuda Rise monitor past Atlantic meridional overturning circulation? Geophys. Res. Lett. 36 L12601 10.1029/2009GL038068 (2009)

    Article  ADS  CAS  Google Scholar 

  25. Boyle, E. A. & Keigwin, L. D. North Atlantic thermohaline circulation during the past 20,000 years linked to high-latitude surface temperature. Nature 330, 35–40 (1987)

    Article  ADS  CAS  Google Scholar 

  26. Siddall, M. et al. Modeling the relationship between 231Pa/230Th distribution in North Atlantic sediment and Atlantic meridional overturning circulation. Paleoceanography 22 PA2214 10.1029/2006PA001358 (2007)

    Article  ADS  Google Scholar 

  27. Piotrowski, A. M., Goldstein, S. L., Hemming, S. R. & Fairbanks, R. G. Temporal relationships of carbon cycling and ocean circulation. Science 307, 1933–1938 (2005)

    Article  ADS  CAS  Google Scholar 

  28. Hughen, K. A. et al. 14C activity and global carbon cycle changes over the past 50,000 years. Science 303, 202–207 (2004)

    Article  ADS  CAS  Google Scholar 

  29. Zahn, R. & Stuber, A. Suborbital intermediate water variability inferred from paired benthic foraminiferal Cd/Ca and δ13C in the tropical West Atlantic and linking with North Atlantic climates. Earth Planet. Sci. Lett. 200, 191–205 (2002)

    Article  ADS  CAS  Google Scholar 

  30. Grootes, P. M. Comparison of the oxygen isotope records from GISP2 and GRIP Greenland ice cores. Nature 366, 552–554 (1993)

    Article  ADS  CAS  Google Scholar 

  31. Negre, C. et al. Separation and measurement of Pa, Th, and U isotopes in marine sediments by microwave-assisted digestion and multiple collector inductively coupled plasma mass spectrometry. Anal. Chem. 81, 1914–1919 (2009)

    Article  CAS  Google Scholar 

  32. Regelous, M., Turner, S. P., Elliott, T. R., Rostami, K. & Hawkesworth, C. J. Measurement of femtogram quantities of protactinium in silicate rock samples by multicollector inductively coupled plasma mass spectrometry. Anal. Chem. 76, 3584–3589 (2004)

    Article  CAS  Google Scholar 

  33. Edwards, R. L., Chen, J. H. & Wasserburg, G. J. 238U-234U 230Th-232Th systematics and the precise measurement of time over the past 500,000 years. Earth Planet. Sci. Lett. 81, 175–192 (1986)

    Article  ADS  Google Scholar 

  34. Taylor, S. R. & McLennan, S. M. The Continental Crust: its Composition and Evolution (Blackwell, 1985)

    Google Scholar 

  35. François, R., Frank, M., Rutgers van der Loeff, M. M. & Bacon, M. P. 230Th normalisation: an essential tool for interpreting sedimentary fluxes during the late Quaternary. Paleoceanography 19 PA1018 10.1029/2003PA000939 (2004)

    Article  ADS  Google Scholar 

  36. Martínez-Méndez, G. et al. Contrasting multi-proxy reconstructions of surface ocean hydrography in the Agulhas Corridor and implications for the Agulhas Leakage during the last 345,000 years. Paleoceanography 10.1029/2009PA001879 (in the press)

  37. Southon, J., Kashgarian, M., Fortugne, M., Metivier, B. & Yim, W. E.-S. Marine reservoir corrections for the Indian Ocean and Southeast Asia. Radiocarbon 44, 167–180 (2002)

    Article  Google Scholar 

  38. Fairbanks, R. G. et al. Radiocarbon calibration curve spanning 0 to 50,000 years BP based on paired 230Th/234U/238U and 14C dates on pristine corals. Quat. Sci. Rev. 24, 1781–1796 (2005)

    Article  ADS  Google Scholar 

  39. Honjo, S. & Manganini, S. J. Annual biogenic particle fluxes to the interior of the North Atlantic Ocean: studied at 34°N 21°W and 48°N 21°W. Deep Sea Res. II 40, 587–607 (1993)

    Article  CAS  Google Scholar 

  40. Martínez-Méndez, G., Zahn, R., Hall, I. R., Pena, L. D. & Cacho, I. 345,000-year long multi-proxy records off South Africa document variable contributions of northern versus southern component water to the deep South Atlantic. Earth Planet. Sci. Lett. 267, 309–321 (2008)

    Article  ADS  Google Scholar 

  41. Shackleton, N. J. Attainment of isotopic equilibrium between ocean water and the benthonic foraminifera genus Uvigerina: isotopic changes in the ocean during the last glacial. Colloq. Int. CNRS 219, 203–209 (1974)

    Google Scholar 

  42. Bianchi, G. G., Hall, I. R., McCave, I. N. & Joseph, L. Measurements of the sortable silt current speed proxy using the Sedigraph 5100 and Coulter Multisizer IIe: precision and accuracy. Sedimentology 46, 1001–1014 (1999)

    Article  ADS  Google Scholar 

  43. Mortlock, R. A. & Froelich, P. N. A simple method for the rapid determination of biogenic opal in pelagic marine sediments. Deep-Sea Res. 36, 1415–1426 (1989)

    Article  ADS  CAS  Google Scholar 

  44. Koroleff, F. in Methods of Seawater Analysis 2nd edn (eds Grasshoff, K., Kremling, K. & Ehrhardt, M.) 174–183 (Verlag Chemie, Weinheim, 1983)

    Google Scholar 

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MD02-2594 and MD02-2588 sediment cores were provided by the International Marine Past Global Changes Study (IMAGES) and the Institute Polaire Français Paul Emile Victor (IPEV). TN057-21 and PS2489-2 samples were supplied by S. Barker and A. Martínez-Garcia. Financial support is acknowledged from the Ministerio de Ciencia e Innovación, Spain, through scholarship AP-2004-4278 to C.N., REN2002-01958 to G.M.-M., and grant CGL2007-61579/CLI and funds from the Comer Abrupt Climate Change Foundation to R.Z. P.M. acknowledges an ICREA Academia award by the Generalitat de Catalunya.

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Authors and Affiliations



R.Z. and P.M. designed the study and supervised C.N. during his PhD.; R.Z. and I.R.H. participated in the retrieval of the sediment cores; C.N. and G.M.-M. sampled the cores; C.N. processed the samples for 231Pa/230Th with help from A.L.T., J.L.M., P.M. and G.M.H.; A.L.T., G.M.H. and C.N. performed the Pa/Th/U measurements and data processing; G.M.-M. performed foraminiferal δ18O and δ13C analyses; I.R.H. provided S̄S̄ data; C.N. analysed opal concentrations; C.N. and R.Z. wrote the paper. All authors contributed to the interpretation of the results and provided input to the manuscript.

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Correspondence to César Negre.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Information

The file contains a brief introduction on 231Pa/230Th as a water flow-rate proxy, Supplementary Figures 1-3 with legends, the data from the Agulhas Plateau and the equatorial Atlantic which help to interpret the MD02-2594 record; the equations used for the calculation of 231Pa/230Th ratios. The file also contains Supplementary Table 1 and additional references. (PDF 767 kb)

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Negre, C., Zahn, R., Thomas, A. et al. Reversed flow of Atlantic deep water during the Last Glacial Maximum. Nature 468, 84–88 (2010).

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