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.
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References
Moore, J. K. & Braucher, O. Sedimentary and mineral dust sources of dissolved iron to the World Ocean. Biogeosciences 4, 1279–1327 (2008).
Tagliabue, A. et al. Hydrothermal contribution to the oceanic dissolved iron inventory. Nature Geosci. 3, 252–256 (2010).
Boyle, E. A. & Jenkins, W. J. Hydrothermal iron in the deep Western South Pacific. Geochem. Cosmochim. Acta 72, A107 (2008).
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).
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).
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).
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).
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).
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).
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).
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).
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).
Sander, S. G. & Koschinsky, A. Metal flux from hydrothermal vents increased by organic complexation. Nature Geosci. 4, 145–150 (2011).
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).
Devey, C. W. et al. Diversity of Hydrothermal Systems on Slow-spreading Ocean Ridges (AGU Monograph, 2010).
Lupton, J. Hydrothermal helium plumes in the Pacific Ocean. J. Geophys. Res. 103, 15853–15868 (1998).
Klinkhammer, G., Rona, P., Greaves, M. & Elderfield, H. Hydrothermal manganese plumes in the Mid-Atlantic Ridge rift valley. Nature 314, 727–731 (1985).
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).
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).
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).
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).
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).
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).
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).
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).
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).
Johnson, K. S. et al. Developing iron standards for seawater. EOS Trans. 88, 131–132 (2007).
Hamme, R. C. & Emerson, S. The solubility of neon, nitrogen and argon in distilled water and seawater. Deep-Sea Res. 51, 1517–1528 (2004).
Roether, W., Well, R., Putzka, A. & Ruth, C. Component separation of oceanic helium. J. Geophys. Res. 103, 27931–27946 (1998).
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).
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.
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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.
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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
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DOI: https://doi.org/10.1038/ngeo1893
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