Ocean pH is particularly sensitive to atmospheric carbon dioxide content1,2,3. Records of ocean pH can therefore be used to estimate past atmospheric carbon dioxide concentrations. The isotopic composition of boron (δ11B) contained in the carbonate shells of marine organisms varies according to pH, from which ocean pH can be reconstructed4,5,6,7,8,9,10,11. This requires independent estimates of the δ11B of dissolved boron in sea water through time. The marine δ11B budget, however, is still largely unconstrained. Here we show that, by incorporating the global flux of riverine boron (as estimated from δ11B measurements in 22 of the world's main rivers), the marine boron isotope budget can be balanced. We also derive ocean δ11B budgets for the past 120 Myr. Estimated isotope compositions of boron in sea water show a remarkable consistency with records of δ11B in foraminiferal carbonates9,10,11, suggesting that foraminifera δ11B records may in part reflect changes in the marine boron isotope budget rather than changes in ocean pH over the Cenozoic era.
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Berner, R. A. The rise of plants and their effect on weathering and atmospheric CO2. Science 276, 544–546 (1997).
Goddéris, Y. & François, L. M. Balancing the Cenozoic carbon and alkalinity cycles: Constraints from isotopic records. Geophys. Res. Lett. 23, 3743–3746 (1996).
McCauley, S. E. & DePaolo, D. J. Tectonic Uplift and Climate Change (Plenum, New York, 1997).
Vengosh, A., Kolodny, Y., Starinsky, A., Chivas, A. R. & McCulloch, M. T. Coprecipitation and isotopic fractionation of boron in modern biogenic carbonates. Geochim. Cosmochim. Acta. 55, 2901–2910 (1991).
Hemming, N. G. & Hanson, G. N. Boron isotopic composition and concentration in modern marine carbonates. Geochim. Cosmochim. Acta. 56, 537–543 (1992).
Spivack, A. J., You, C. F. & Smith, J. Foraminiferal boron isotope ratios as a proxy for surface ocean pH over the past 21 Myr. Nature 363, 149–151 (1993).
Gaillardet, J. & Allègre, C. J. Boron isotopic compositions of corals : seawater or diagenesis record? Earth Planet. Sci. Lett. 136, 665–676 (1995).
Sanyal, A., Hemming, N. G., Hanson, G. N. & Broecker, W. S. Evidence for a higher pH in the glacial ocean from boron isotopes in foraminifera. Nature 373, 234–236 (1995).
Palmer, M. R., Pearson, P. N. & Cobb, S. J. Reconstructing past ocean pH-depth profiles. Science 282, 1468–1471 (1998).
Pearson, P. N. & Palmer, M. R. Middle Eocene seawater pH and atmospheric carbon dioxide concentrations. Science 284, 1824–1826 (1999).
Pearson, P. N. & Palmer, M. R. Atmospheric carbon dioxide concentrations over the past 60 million years. Nature 406, 695–699 (2000).
Spivack, A. J. & Edmond, J. M. Boron isotope exchange between seawater and the oceanic crust. Geochim. Cosmochim. Acta 51, 1033–1043 (1987).
Smith, H. J., Spivack, A. J., Staudigel, H. & Hart, S. R. The boron isotopic composition of altered oceanic crust. Chem. Geol. 126, 119–135 (1995).
Schwarcz, H. P., Agyei, E. K. & McMullen, C. C. Boron isotopic fractionation during clay adsorption from sea-water. Earth Planet. Sci. Lett. 6, 1–5 (1969).
Spivack, A. J., Palmer, M. R. & Edmond, J. M. The sedimentary cycle of the boron isotopes. Geochim. Cosmochim. Acta 51, 1939–1949 (1987).
Spivack, A. J. Boron Isotope Geochemistry. Thesis, Massachussetts Institute of Technology/Woods Hole Oceanographic Institute (1986).
Rose, E. F., Chaussidon, M. & France-Lanord, C. Fractionation of boron isotopes during erosion processes: the example of Himalayan rivers. Geochim. Cosmochim. Acta 64, 397–408 (2000).
Lemarchand, D., Gaillardet, J., Göpel, C. & Manhès, G. An optimized procedure for boron separation and mass spectrometry for river water samples. Chem. Geol. (submitted).
Harriss, R. C. Boron regulation in the oceans. Nature 223, 290–291 (1969).
Vengosh, A., Spivack, A. J., Artzi, Y. & Ayalon, A. Geochemical and boron, strontium, and oxygen isotopic constrains on the origin of the salinity in groundwater from the Mediterranean coast of Israel. Wat. Resour. Res. 35, 1877–1894 (1998).
Reimann, C. & Caritat, P. Chemical Elements in the Environment (Springer, Berlin, 1998).
Larson, R. L. The Mid-Cretaceous superplume episode. Sci. Am. 272, 66–70 (1995).
Goddéris, Y. Modelisation de l’Évolution Cénozoı¨que des Cycles Biogéochimiques : Impact de l’Orogénèse Himalayenne. Thesis, Univ. Liège (1997).
Opdyke, B. N. & Wilkinson, B. H. Surface area control of shallow cratonic to deep marine carbonate accumulation. Paleoceanography 3, 685–703 (1988).
Gibbs, M. T., Bluth, G. J. S., Fawcett, P. J. & Kump, L. R. Global chemical erosion over the last 250 My: variations due to changes in paleogeography, paleoclimate, and paleogeology. Am. J. Sci. 299, 611–651 (1999).
Berner, R. A. GEOCARB II: A revised model of atmospheric CO2 over Phanerozoic time. Am. J. Sci. 294, 56–91 (1994).
You, C. F., Spivack, A. J., Smith, J. H. & Gieskes, J. M. Mobilization of boron in convergent margins: implications for the boron geochemical cycle. Geology 21, 207–210 (1993).
You, C. F., Spivack, A. J., Gieskes, J. M., Rosenbauer, R. & Bishoff, J. L. Experimental study of boron geochemistry : Implications for fluid processes in subduction zones. Geochim. Cosmochim. Acta 59, 2435–2442 (1995).
Milliman, J. D. & Syvitski, J. P. M. Geomorphic/tectonic control of sediment discharge to the ocean: the importance of small mountainous rivers. J. Geol. 100, 525–544 (1992).
We thank R. A. Berner, G. N. Hemming, A. J. Spivack, E. Young and B. Bourdon for comments on the manuscript. We also thank the following for sampling facilities: T. Allard, M. Benedetti, M. Blasco, F. Bodet, G. J. Chakrapani, B. Dupré, C. Gariépi, W. Li, P. Negrel, V. Rachold, V. Subramanian and J. Zhao.
About this article
Cite this article
Lemarchand, D., Gaillardet, J., Lewin, É. et al. The influence of rivers on marine boron isotopes and implications for reconstructing past ocean pH. Nature 408, 951–954 (2000) doi:10.1038/35050058
Macro-sublimation: Purification of boron in low-concentration geological samples for isotopic determination by MC-ICPMS
Microchemical Journal (2020)
LA-MC-ICP-MS study of boron isotopes in individual planktonic foraminifera: A novel approach to obtain seasonal variability patterns
Chemical Geology (2020)
Paleoceanography and Paleoclimatology (2019)
Source and evolution of dissolved boron in rivers: Insights from boron isotope signatures of end-members and model of boron isotopes during weathering processes
Earth-Science Reviews (2019)
Geochemistry International (2019)