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.

Slow-spreading submarine ridges in the South Atlantic as a significant oceanic iron source

Abstract

Low levels of the micronutrient iron limit primary production and nitrogen fixation in large areas of the global ocean. The location and magnitude of oceanic iron sources remain uncertain, however, owing to a scarcity of data, particularly in the deep ocean1. Although deep-sea hydrothermal vents along fast-spreading ridges have been identified as important contributors to the oceanic iron inventory2, slow-spreading ridges, which contribute more than half of the submarine ridge-crest environment, are assumed to be less significant and remain relatively unexplored2. Here, we present measurements of dissolved iron and manganese concentrations along a full-depth section in the South Atlantic Ocean, running from offshore of Brazil to Namibia. We detect a large dissolved iron- and manganese-rich plume over the slow-spreading southern Mid-Atlantic Ridge. Using previously collected measurements of helium-3 concentrations—a tracer of hydrothermal activity—we calculate the ratio of dissolved iron to hydrothermal helium in the plume waters and find that it is 80-fold higher than that reported for plume waters emanating from faster-spreading ridges in the southeastern Pacific3. Only the application of a higher ratio in global ocean model simulations yields iron fluxes from these slow-spreading submarine ridges that are in line with our observations. We suggest that global iron contributions from hydrothermal vents are significantly higher than previously thought, owing to a greater contribution from slow-spreading regions.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: A zonal section of dFe and dMn in the South Atlantic.
Figure 2: Vertical profiles from the vicinity of the MAR of the South Atlantic Ocean and comparison with 3He distributions.

References

  1. Moore, J. K. & Braucher, O. Sedimentary and mineral dust sources of dissolved iron to the World Ocean. Biogeosciences 4, 1279–1327 (2008).

    Article  Google Scholar 

  2. Tagliabue, A. et al. Hydrothermal contribution to the oceanic dissolved iron inventory. Nature Geosci. 3, 252–256 (2010).

    Article  Google Scholar 

  3. Boyle, E. A. & Jenkins, W. J. Hydrothermal iron in the deep Western South Pacific. Geochem. Cosmochim. Acta 72, A107 (2008).

    Google Scholar 

  4. Edmond, J. M., Von Damm, K. L., McDuff, R. E. & Measures, C. I. Chemistry of hot springs on the East Pacific Rise and their effluent dispersal. Nature 297, 187–191 (1982).

    Article  Google Scholar 

  5. German, C. R. et al. Heat, volume and chemical fluxes from submarine venting: A synthesis of results from the Rainbow hydrothermal field, 36° N MAR. Deep Sea Res. 57, 518–527 (2010).

    Article  Google Scholar 

  6. Elderfield, H. & Schultz, A. Mid-ocean ridge hydrothermal fluxes and the chemical composition of the ocean. Annu. Rev. Earth. Planet. Sci. 24, 191–224 (1996).

    Article  Google Scholar 

  7. Field, M. P. & Sherrell, R. M. Dissolved and particulate Fe in a hydrothermal plume at 9° 45′ N, East Pacific Rise::Slow Fe(II) oxidation kinetics in Pacific plumes. Geochim. Cosmochim. Acta 64, 619–628 (2000).

    Article  Google Scholar 

  8. Bennett, S. A. et al. The distribution and stabilisation of dissolved Fe in deep-sea hydrothermal plumes. Earth Planet. Sci. Lett. 270, 157–167 (2008).

    Article  Google Scholar 

  9. Statham, P. J., German, C. R. & Connelly, D. P. Iron (II) distribution and oxidation kinetics in hydrothermal plumes at the Kairei and Edmond vent sites, Indian Ocean. Earth Planet. Sci. Lett. 236, 588–596 (2005).

    Article  Google Scholar 

  10. Wu, J., Wells, M. L. & Rember, R. Dissolved iron anomaly in the deep tropical–subtropical Pacific: Evidence for long-range transport of hydrothermal iron. Geochim. Cosmochim. Acta 75, 460–468 (2011).

    Article  Google Scholar 

  11. Klunder, M., Laan, P., Middag, R., Baar, H. J. W. D. & Ooijen, J. V. Dissolved iron in the Southern Ocean (Atlantic sector). Deep-Sea Res. II 58, 2678–2694 (2011).

    Article  Google Scholar 

  12. Boyle, E. A., Bergquist, B. A., Kayser, R. A. & Mahowald, N. Iron, manganese, and lead at Hawaii Ocean Time-series station ALOHA: Temporal variability and an intermediate water hydrothermal plume. Geochim. Cosmo. Acta 69, 933–952 (2005).

    Article  Google Scholar 

  13. Sander, S. G. & Koschinsky, A. Metal flux from hydrothermal vents increased by organic complexation. Nature Geosci. 4, 145–150 (2011).

    Article  Google Scholar 

  14. Yucel, M., Gartman, A., Chan, C. S. & Luther, G. W. Hydrothermal vents as a kinetically stable source of iron-sulphide-bearing nanoparticles to the ocean. Nature Geosci. 4, 367–371 (2011).

    Article  Google Scholar 

  15. Devey, C. W. et al. Diversity of Hydrothermal Systems on Slow-spreading Ocean Ridges (AGU Monograph, 2010).

    Google Scholar 

  16. Lupton, J. Hydrothermal helium plumes in the Pacific Ocean. J. Geophys. Res. 103, 15853–15868 (1998).

    Article  Google Scholar 

  17. Klinkhammer, G., Rona, P., Greaves, M. & Elderfield, H. Hydrothermal manganese plumes in the Mid-Atlantic Ridge rift valley. Nature 314, 727–731 (1985).

    Article  Google Scholar 

  18. German, C. R. et al. Hydrothermal activity on the southern Mid-Atlantic Ridge: Tectonically- and volcanically-controlled venting at 4–5°S. Earth Planet. Sci. Lett. 273, 332–344 (2008).

    Article  Google Scholar 

  19. Melchert, B. et al. First evidence for high-temperature off-axis venting of deep crustal/mantle heat: The Nibelungen hydrothermal field, southern Mid-Atlantic Ridge. Earth Planet. Sci. Lett. 275, 61–69 (2008).

    Article  Google Scholar 

  20. Haase, K. M. et al. Diking, young volcanism and diffuse hydrothermal activity on the southern Mid-Atlantic Ridge: The Lilliput field at 9°33′ S. Mar. Geol. 266, 52–64 (2009).

    Article  Google Scholar 

  21. Ruth, C., Well, R. & Roether, W. Primordial 3He in South Atlantic deep waters from sources on the Mid-Atlantic Ridge. Deep-Sea Res. 47, 1059–1075 (2000).

    Article  Google Scholar 

  22. Lupton, J. E., Pyle, D. G., Jenkins, W. J., Greene, R. & Evans, L. Evidence for an extensive hydrothermal plume in the Tonga-Fiji region of the South Pacific. Geochem. Geophys. Geosyst. 5, Q01003 (2004).

    Article  Google Scholar 

  23. Kuma, K., Nishioka, J. & Matsunaga, K. Controls on iron(III) hydroxide solubility in seawater: The influence of pH and natural organic chelators. Limnol. Oceanogr. 41, 396–407 (1996).

    Article  Google Scholar 

  24. Keir, R. S. et al. Flux and dispersion of gases from the ‘Drachenschlund’ hydrothermal vent at 8° 18′ S, 13° 30′ W on the Mid-Atlantic Ridge. Earth Planet. Sci. Lett. 270, 338–348 (2008).

    Article  Google Scholar 

  25. Douville, E. et al. The rainbow vent fluids (36° 14′ N, MAR): The influence of ultramafic rocks and phase separation on trace metal content in Mid-Atlantic Ridge hydrothermal fluids. Chem. Geol. 184, 37–48 (2002).

    Article  Google Scholar 

  26. Saito, M. A. & Schneider, D. L. Examination of precipitation chemistry and improvements in precision using the Mg(OH)2 preconcentration ICP-MS method for high-throughput analysis of open-ocean Fe and Mn in seawater. Anal. Chim. Acta 565, 222–233 (2006).

    Article  Google Scholar 

  27. Johnson, K. S. et al. Developing iron standards for seawater. EOS Trans. 88, 131–132 (2007).

    Article  Google Scholar 

  28. Hamme, R. C. & Emerson, S. The solubility of neon, nitrogen and argon in distilled water and seawater. Deep-Sea Res. 51, 1517–1528 (2004).

    Article  Google Scholar 

  29. Roether, W., Well, R., Putzka, A. & Ruth, C. Component separation of oceanic helium. J. Geophys. Res. 103, 27931–27946 (1998).

    Article  Google Scholar 

  30. Chever, F. et al. Physical speciation of iron in the Atlantic sector of the Southern Ocean along a transect from the subtropical domain to the Weddell Sea Gyre. J. Geophys. Res. 115, C10059 (2010).

    Article  Google Scholar 

Download references

Acknowledgements

We are indebted to the captain and crew of the RV Knorr for their considerable efforts in the sampling of this zonal section. We also thank P. Lam, C. Hammerschmidt and A. Cox for assistance at sea, S. Birdwhistell for assistance in the WHOI inductively coupled plasma mass spectrometry facility and C. German, C. Devey and G. Henderson for conversations. We thank the GEOTRACES community and intercalibration programme. We thank J. Resing for comments. This research was financially supported by the US NSF-Chemical Oceanography programme (OCE-0452883, OCE-0752291, OCE-0928414, OCE-1031271 and OCE-1233261) and the Gordon and Betty Moore Foundation Grant @2724.

Author information

Authors and Affiliations

Authors

Contributions

The ocean section sampling expedition plan was designed by M.A.S. and C.H.L. The field sampling programme was orchestrated and implemented by T.J.G., M.A.S., C.H.L. and A.E.N. (also see Acknowledgements). Fe and Mn analyses were made by A.E.N. Optimum multiparameter analysis and gridding analyses were conducted by W.J.J. A.T. analysed the NEMO-PISCES model output comparison. Data analysis and interpretation was conducted by M.A.S., W.J.J., A.T., A.E.N. and C.H.L. The manuscript was written by M.A.S., W.J.J., A.T., A.E.N. and C.H.L.

Corresponding authors

Correspondence to Mak A. Saito or William J. Jenkins.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 707 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Saito, M., Noble, A., Tagliabue, A. et al. Slow-spreading submarine ridges in the South Atlantic as a significant oceanic iron source. Nature Geosci 6, 775–779 (2013). https://doi.org/10.1038/ngeo1893

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/ngeo1893

Further reading

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