Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

The isotopic signature of the global riverine molybdenum flux and anoxia in the ancient oceans

Nature Geoscience volume 1, pages 597–600 (2008)Cite this article

Abstract

Despite its important biological and biogeochemical consequences1,2,3, the identification of extensive oceanic anoxia in the geological record is controversial. In particular, global anoxia is difficult to distinguish from spatially restricted anoxia in the deep ocean, or in tectonically isolated basins such as the modern Black Sea. The marine isotope geochemistry of molybdenum (Mo) can help quantify the past oxygenation state of the ocean4,5,6,7,8,9,10,11,12,13,14, because to first approximation under oxic conditions lighter isotopes of Mo are preferentially removed to sediments, whereas in euxinic conditions quantitative removal leads to no fractionation. However, the isotopic composition of the Mo input from rivers, the main contributor of Mo to the oceans, is poorly constrained and had been assumed to be isotopically comparable to the narrow range found in a small dataset of continental rocks4,5,6,7,8,9,10,11,12,13,14. Here we present an isotopic analysis of Mo in a set of rivers that together account for 22% of the global riverine water discharge. We find a broad range of variability in the Mo isotopic composition of these rivers, with almost all samples enriched in the heavy isotopes compared with continental rocks. Our data remove key uncertainties associated with the marine Mo isotope budget14 and strongly suggest near-total anoxia in the mid-Proterozoic ocean8 as well as during Mesozoic ocean anoxic events13.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Mo isotope and concentration data for major rivers.
Figure 2: Mo isotope and concentration data for riverine particulates and an estuary.
Figure 3: Quantitative model of Mo isotope balance in the present and past oceans.

Similar content being viewed by others

References

  1. Anbar, A. D. & Knoll, A. H. Proterozoic ocean chemistry and evolution: A bioinorganic bridge? Science 297, 1137–1142 (2002).

    Article  Google Scholar 

  2. Grice, K. et al. Photic zone euxinia during the Permian–Triassic superanoxic event. Science 307, 706–709 (2005).

    Article  Google Scholar 

  3. Jenkyns, H. C. Evidence for rapid climate change in the Mesozoic–Palaeogene greenhouse world. Phil. Trans. R. Soc. London A 361, 1885–1916 (2003).

    Article  Google Scholar 

  4. Barling, J., Arnold, G. L. & Anbar, A. D. Natural mass-dependent variations in the isotopic composition of molybdenum. Earth Planet. Sci. Lett. 193, 447–457 (2001).

    Article  Google Scholar 

  5. McManus, J., Nägler, T. F., Siebert, C., Wheat, C. F. & Hammond, D. E. Oceanic molybdenum isotope fractionation: Diagensis and hydrothermal ridge-flank alteration. Geochem. Geophys. Geosyst. 3, doi:10.1029/2002GC000356 (2002).

  6. Siebert, C., Nägler, T. F., von Blanckenburg, F. & Kramers, J. D. Molybdenum isotope records as a potential new proxy for paleoceanography. Earth Planet. Sci. Lett. 211, 159–171 (2003).

    Article  Google Scholar 

  7. Barling, J. & Anbar, A. D. Molybdenum isotope fractionation during adsorption by manganese oxides. Earth Planet. Sci. Lett. 217, 315–329 (2004).

    Article  Google Scholar 

  8. Arnold, G. L., Anbar, A. D., Barling, J. & Lyons, T. W. Molybdenum isotope evidence for widespread anoxia in Mid-Proterozoic oceans. Science 304, 87–89 (2004).

    Article  Google Scholar 

  9. Nägler, T. F., Siebert, C., Lüschen, H. & Böttcher, M. E. Sedimentary Mo isotope record across the Holocene fresh–brackish water transition of the Black Sea. Chem. Geol. 219, 283–295 (2005).

    Article  Google Scholar 

  10. Siebert, C., McManus, J., Bice, A., Poulson, R. & Berelson, W. M. Molybdenum isotope signatures in continental margin marine sediments. Earth Planet. Sci. Lett. 241, 723–733 (2006).

    Article  Google Scholar 

  11. Poulson, R., Siebert, C., McManus, J. & Berelson, W. M. Authigenic molybdenum isotope signatures in marine sediments. Geology 34, 617–620 (2006).

    Article  Google Scholar 

  12. McManus, J. et al. Molybdenum and uranium geochemistry in continental margin sediments: Paleoproxy potential. Geochim. Cosmochim. Acta 70, 4643–4662 (2006).

    Article  Google Scholar 

  13. Pearce, C. R., Cohen, A. S., Coe, A. L. & Burton, K. W. Molybdenum isotope evidence for global ocean anoxia coupled with perturbations to the carbon cycle during the early Jurassic. Geology 36, 231–234 (2008).

    Article  Google Scholar 

  14. Ling, H.-F., Gao, J.-F., Zhao, K.-D., Jiang, S.-Y. & Ma, D.-S. Comment on ‘Molybdenum isotope evidence for widespread anoxia in the Mid-Proterozoic oceans’. Science 309, 1017c (2005).

    Article  Google Scholar 

  15. Morford, J. L. & Emerson, S. The geochemistry of redox sensitive trace metals in sediments. Geochim. Cosmochim. Acta 63, 1735–1750 (1999).

    Article  Google Scholar 

  16. Anbar, A. D. & Rouxel, O. Metal stable isotopes in paleoceanography. Annu. Rev. Earth Planet. Sci. 31, 717–746 (2007).

    Article  Google Scholar 

  17. Erickson, B. E. & Helz, G. R. Molybdenum (VI) speciation in sulfidic waters: Stability and lability of thiomolybdenites. Geochim. Cosmochim. Acta 64, 1149–1158 (2000).

    Article  Google Scholar 

  18. Kaback, D. S. & Runnells, D. D. Geochemistry of molybdenum in some stream sediments and waters. Geochim. Cosmochim. Acta 44, 447–456 (1980).

    Article  Google Scholar 

  19. Bertine, K. K. The Marine Geochemical Cycle of Chromium and Molybdenum. Thesis, Yale, 67 (1970).

  20. Malinovsky, D., Hammarlund, D., Ilyashuk, B., Martinsson, O. & Gelting, J. Variations in the isotopic composition of molybdenum in freshwater lake systems. Chem. Geol. 236, 181–198 (2007).

    Article  Google Scholar 

  21. Pontér, C., Ingri, J. & Boström, K. Geochemistry of manganese in the Kalix River, northern Sweden. Geochim. Cosmochim. Acta 56, 1485–1494 (1992).

    Article  Google Scholar 

  22. Rondeau, B., Cossa, D., Gagnon, P., Pham, T. T. & Surette, C. Hydrological and biogeochemical dynamics of the minor and trace elements in the St. Lawrence River. Appl. Geochem. 20, 1391–1408 (2005).

    Article  Google Scholar 

  23. Huh, Y., Chan, L. H., Zhang, L. & Edmond, J. M. Lithium and its isotopes in major world rivers: Implications for weathering and the oceanic budget. Geochim. Cosmochim. Acta 62, 2039–-2051 (1998).

    Article  Google Scholar 

  24. Goldberg, S. & Forster, H. S. Factors affecting molybdenum adsorption by soils and minerals. Soil Sci. 163, 109–114 (1998).

    Article  Google Scholar 

  25. Kisakurek, B., James, R. H. & Harris, N. B. W. Li and δ7Li in Himalayan rivers: Proxies for silicate weathering? Earth Planet. Sci. Lett. 237, 387–401 (2005).

    Article  Google Scholar 

  26. Holland, H. D. in Treatise in Geochemistry (eds Holland, H. D. & Turekian, K. K.) 583–625 (Elsevier, Oxford, 2004).

    Google Scholar 

  27. Canfield, D. E. A new model for Proterozoic ocean chemistry. Nature 396, 450–453 (1998).

    Article  Google Scholar 

  28. Bermin, J., Vance, D., Archer, C. & Statham, P. J. The determination of the isotopic composition of Cu and Zn in seawater. Chem. Geol. 226, 280–297 (2006).

    Article  Google Scholar 

  29. Archer, C. & Vance, D. Mass discrimination correction in plasma source mass spectrometry: An example using Cu and Zn isotopes. J. Anal. Atom. Spectr. 19, 656–665 (2004).

    Article  Google Scholar 

  30. Siebert, C., Nägler, T. F. & Kramer, J. D. Determination of molybdenum isotope fractionation by double-spike multicollector inductively coupled mass spectrometry. Geochem. Geophys. Geosyst. 2, 2000GC000124 (2001).

    Article  Google Scholar 

Download references

Acknowledgements

This research was supported by the NERC. We also thank J. Perkins, R. Mills, D. Teagle, A. Scrivner, A. El Sheikh, H. Kerr, J. Simpson, A. Page and N. Harris for their help with collection of the various river samples. We thank T. Elliott, C. Hawkesworth, J. McManus, A. Anbar for comments on an earlier draft. Jim’s review, particularly, fundamentally changed and improved the manuscript.

Author information

Authors and Affiliations

  1. Department of Earth Sciences, Bristol Isotope Group, University of Bristol, Wills Memorial Building, Queen’s Road, Bristol BS8 1RJ, UK

    C. Archer & D. Vance

Authors
  1. C. Archer
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. D. Vance
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to C. Archer.

Supplementary information

Supplementary Information

Supplementary tables S1-S2 (PDF 116 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Archer, C., Vance, D. The isotopic signature of the global riverine molybdenum flux and anoxia in the ancient oceans. Nature Geosci 1, 597–600 (2008). https://doi.org/10.1038/ngeo282

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/ngeo282

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing