Iron persistence in a distal hydrothermal plume supported by dissolved–particulate exchange

Journal name:
Nature Geoscience
Year published:
Published online


Hydrothermally sourced dissolved metals have been recorded in all ocean basins. In the oceans’ largest known hydrothermal plume, extending westwards across the Pacific from the Southern East Pacific Rise, dissolved iron and manganese were shown by the GEOTRACES program to be transported halfway across the Pacific. Here, we report that particulate iron and manganese in the same plume also exceed background concentrations, even 4,000km from the vent source. Both dissolved and particulate iron deepen by more than 350m relative to 3He—a non-reactive tracer of hydrothermal input—crossing isopycnals. Manganese shows no similar descent. Individual plume particle analyses indicate that particulate iron occurs within low-density organic matrices, consistent with its slow sinking rate of 5–10myr−1. Chemical speciation and isotopic composition analyses reveal that particulate iron consists of Fe(III) oxyhydroxides, whereas dissolved iron consists of nanoparticulate Fe(III) oxyhydroxides and an organically complexed iron phase. The descent of plume-dissolved iron is best explained by reversible exchange onto slowly sinking particles, probably mediated by organic compounds binding iron. We suggest that in ocean regimes with high particulate iron loadings, dissolved iron fluxes may depend on the balance between stabilization in the dissolved phase and the reversibility of exchange onto sinking particles.

At a glance


  1. Interpolated concentrations and station map along the US GEOTRACES GP16 Eastern Pacific Zonal Transect.
    Figure 1: Interpolated concentrations and station map along the US GEOTRACES GP16 Eastern Pacific Zonal Transect.

    a, Station locations and names in relation to the South American continent and the East Pacific Rise (colours are bathymetry; green hues shallower) b, Excess 3He concentrations in fmolkg−1. c, Dissolved Fe concentrations (<0.2μm, in nM). d, Dissolved Mn concentrations (<0.2μm, in nM). e, Particulate Fe (>0.45μm, in nM). f, Particulate Mn (>0.45μm, in pM). Note that in each panel a black reference line is indicated at 2,500m to highlight the deepening of the Fe plumes. The simulations were carried out using Ocean Data View.

  2. Illustration of Fe, Mn and 3Hexs transport and transformation along the SEPR hydrothermal plume.
    Figure 2: Illustration of Fe, Mn and 3Hexs transport and transformation along the SEPR hydrothermal plume.

    Physical plume bounds are indicated in grey, at representative nonlinear distances off-axis (labelled at bottom). Concentric circles represent relative concentrations of particulate and dissolved metals; circle sizes represent relative concentrations but are not quantitatively accurate among Fe, Mn and 3Hexs maxima. Pie diagrams show chemical speciation of dissolved Fe. Particulate Fe and Mn are removed through aggregation onto sinking particles from above (white arrows43) and through near-field self-aggregation of hydrothermally sourced particles. Note that Fe descends relative to Mn and 3Hexs, which mix along slightly deepening isopycnals.

  3. Relationship between excess 3He and metal inventories in the dissolved and particulate phases in the SEPR hydrothermal plume (2,200-3,000[thinsp]m).
    Figure 3: Relationship between excess 3He and metal inventories in the dissolved and particulate phases in the SEPR hydrothermal plume (2,200–3,000m).

    a,b, Inventories for Fe and Mn, respectively. All stations are included with the exception of Sta. 18 (directly over vent). Sta. 20 is plotted as open circles for Mn because those points fall off of the distal plume trend8. Integrating between 2,200–3,000m captures the entirety of the sinking Fe plume. Linear relationships between 3Hexs and dissolved metals suggest that dissolved metal inventories are apparently conserved (controlled by mixing/dilution), whereas the exponential relationship between particulate metals and 3Hexs indicates aggregative removal of particles to >3,000m depth.

  4. Depth of peak concentrations in the SEPR hydrothermal plume.
    Figure 4: Depth of peak concentrations in the SEPR hydrothermal plume.

    a,b, Vertical bars indicate depths where concentrations were within 2.5% of maximum. The 27.737 line is the potential density layer on which maximum 3Hexs was emplaced at Sta. 20; this is the isopycnal surface on which all dissolved species should have travelled. Notably, Fe species deepened (a), falling below this isopycnal, whereas Mn species mixed along it (b). The label ‘dFe-Resing’ indicates dFe maxima published previously8, while ‘dFe-John’ are independent, mass spectrometric dFe measurements reported here; we report both to show that the pattern of dFe descent is reproducible and unrelated to data error.

  5. Scanning transmission X-ray microscopy (STXM) images, elemental maps, and spectra for representative plume particles (>0.2[thinsp][mu]m).
    Figure 5: Scanning transmission X-ray microscopy (STXM) images, elemental maps, and spectra for representative plume particles (>0.2μm).

    a,d, Transmission images collected at 290eV. b,e, Distribution of total carbon with optical density of 1.8 (b) and 0.63 (e). c,f, Distribution of total iron with optical density of 2.6 (c) and 0.57 (f). Note that f does not cover the whole of the area imaged in d and e. g, Carbon 1s XANES spectra for particulate organic carbon from Sta. 20–21. h, Iron 2p XANES spectrum for particulate Fe(III) from Sta. 20–21, compared to standard ferrihydrite. All scale bars 2μm.

  6. Dissolved and labile particulate [delta]56Fe results for hydrothermal depths 2,200-2,800[thinsp]m.
    Figure 6: Dissolved and labile particulate δ56Fe results for hydrothermal depths 2,200–2,800m.

    a, Constant labile particulate50 δ56 Fe (−0.25 ± 0.14‰) over a wide range of pFe concentrations suggests that pFe loss is controlled by non-fractionating, physical aggregation/disaggregation processes. b, Dissolved δ56Fe increases down-plume, modelled as mixing (black line) between a hydrothermal nanoparticulate Fe(III) oxyhydroxide endmember (−0.19‰) and an isotopically heavier ligand-bound phase (+0.66‰, 0.77nM; background and hydrothermal FeL complexes). Errors in [Fe] and particulate δ56Fe are smaller than data points (5% and 0.02–0.03‰, 2σs.e.m., respectively). Errors for some Sta. 20 dissolved δ56Fe were unusually high because of an incorrect dilution (light grey).


  1. German, C. R. & Seyfried, W. E. in Treatise on Geochemistry Vol. 8 2nd edn (eds Holland, H. D. & Turekian, K. K.) 191233 (Elsevier, 2014).
  2. Sunda, W. G. Feedback interactions between trace metal nutrients and phytoplankton in the ocean. Front. Microbiol. 3, 204 (2012).
  3. Tagliabue, A. et al. How well do global ocean biogeochemistry models simulate dissolved iron distributions? Glob. Biogeochem. Cycles 30, 149174 (2016).
  4. 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, 619628 (2000).
  5. German, C. R., Campbell, A. C. & Edmond, J. M. Hydrothermal scavenging at the Mid-Atlantic Ridge: modification of trace element dissolved fluxes. Earth Planet. Sci. Lett. 107, 101114 (1991).
  6. 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, 460468 (2011).
  7. Fitzsimmons, J. N., Jenkins, W. J. & Boyle, E. A. Distal transport of dissolved hydrothermal iron in the deep South Pacific Ocean. Proc. Natl Acad. Sci. USA 111, 1665416661 (2014).
  8. Resing, J. A. et al. Basin-scale transport of hydrothermal dissolved metals across the South Pacific Ocean. Nature 523, 200206 (2015).
  9. Noble, A. E. et al. Basin-scale inputs of cobalt, iron, and manganese from the Benguela–Angola front to the South Atlantic Ocean. Limnol. Oceanogr. 57, 9891010 (2012).
  10. Fitzsimmons, J. N. et al. Partitioning of dissolved iron and iron isotopes into soluble and colloidal phases along the GA03 GEOTRACES North Atlantic Transect. Deep-Sea Res. II 116, 130151 (2015).
  11. Nishioka, J., Obata, H. & Tsumune, D. Evidence of an extensive spread of hydrothermal dissolved iron in the Indian Ocean. Earth Planet. Sci. Lett. 361, 2633 (2013).
  12. Klunder, M. B., Laan, P., Middag, R., De Baar, H. J. W. & van Ooijen, J. C. Dissolved iron in the Southern Ocean (Atlantic sector). Deep-Sea Res. II 58, 26782694 (2011).
  13. Hawkes, J. A., Connelly, D. P., Rijkenberg, M. J. A. & Achterberg, E. P. The importance of shallow hydrothermal island arc systems in ocean biogeochemistry. Geophys. Res. Lett. 41, 2013GL058817 (2014).
  14. Klunder, M. B., Laan, P., Middag, R., de Baar, H. J. W. & Bakker, K. Dissolved iron in the Arctic Ocean: important role of hydrothermal sources, shelf input and scavenging removal. J. Geophys. Res. 117, C04014 (2012).
  15. 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. Nat. Geosci. 4, 367371 (2011).
  16. Sands, C. M., Connelly, D. P., Statham, P. J. & German, C. R. Size fractionation of trace metals in the Edmond hydrothermal plume, Central Indian Ocean. Earth Planet. Sci. Lett. 319–320, 1522 (2012).
  17. Gartman, A., Findlay, A. J. & Luther, G. W. III Nanoparticulate pyrite and other nanoparticles are a widespread component of hydrothermal vent black smoker emissions. Chem. Geol. 366, 3241 (2014).
  18. Bennett, S. A. et al. The distribution and stabilisation of dissolved Fe in deep-sea hydrothermal plumes. Earth Planet. Sci. Lett. 270, 157167 (2008).
  19. Sander, S. G. & Koschinsky, A. Metal flux from hydrothermal vents increased by organic complexation. Nat. Geosci. 4, 145150 (2011).
  20. Hawkes, J. A., Connelly, D. P., Gledhill, M. & Achterberg, E. P. The stabilisation and transportation of dissolved iron from high temperature hydrothermal vent systems. Earth Planet. Sci. Lett. 375, 280290 (2013).
  21. Feely, R. A. et al. Hydrothermal plume particles and dissolved phosphate over the superfast-spreading southern East Pacific Rise. Geochim. Cosmochim. Acta 60, 22972323 (1996).
  22. Boström, K., Peterson, M. N. A., Joensuu, O. & Fisher, D. E. Aluminum-poor ferromanganoan sediments on active oceanic ridges. J. Geophys. Res. 74, 32613270 (1969).
  23. Lupton, J. Hydrothermal helium plumes in the Pacific Ocean. J. Geophys. Res. 103, 1585315868 (1998).
  24. Black, E. E., Buesseler, K. O., Pike, S. M., Lam, P. J. & Charette, M. A.234Th Distribution along the Eastern Pacific GEOTRACES Transect and Implications for Export and Remineralization Fluxes of Carbon and TEIs Ocean Sciences Meeting, New Orleans, Louisiana. CT24A-0140 (2016).
  25. Hautala, S. L. & Riser, S. C. A nonconservative β-spiral determination of the deep circulation in the Eastern South Pacific. J. Phys. Oceanogr. 23, 19752000 (1993).
  26. Faure, V. & Speer, K. Deep circulation in the eastern South Pacific Ocean. J. Mar. Res. 70, 748778 (2012).
  27. Toner, B. M. et al. Preservation of iron(II) by carbon-rich matrices in a hydrothermal plume. Nat. Geosci. 2, 197201 (2009).
  28. Cowen, J. P., Massoth, G. J. & Baker, E. T. Bacterial scavenging of Mn and Fe in a mid- to far-field hydrothermal particle plume. Nature 322, 169171 (1986).
  29. Cowen, J. P., Massoth, G. J. & Feely, R. A. Scavenging rates of dissolved manganese in a hydrothermal vent plume. Deep-Sea Res. A 37, 16191637 (1990).
  30. Nealson, K. H., Tebo, B. M. & Rosson, R. A. Occurrence and mechanisms of microbial oxidation of manganese. Adv. Appl. Microbiol. 33, 279318 (1988).
  31. Toner, B. M. et al. The Speciation of Particulate Iron and Carbon in the East Pacific Rise 15°S Near-Field Hydrothermal Plume and Underlying Sediments AGU Fall Meeting (2014).
  32. Dauphas, N. & Rouxel, O. Mass spectrometry and natural variations of iron isotopes. Mass Spectrom. Rev. 25, 515550 (2006).
  33. Wells, M. L. & Goldberg, E. D. Marine submicron particles. Mar. Chem. 40, 518 (1992).
  34. Bennett, S. A. et al. Iron isotope fractionation in a buoyant hydrothermal plume, 5S Mid-Atlantic Ridge. Geochim. Cosmochim. Acta 73, 56195634 (2009).
  35. Dideriksen, K., Baker, J. A. & Stipp, S. L. S. Equilibrium Fe isotope fractionation between inorganic aqueous Fe(III) and the siderophore complex, Fe(III)-desferrioxamine B. Earth Planet. Sci. Lett. 269, 280290 (2008).
  36. Morgan, J. L. L., Wasylenki, L. E., Nuester, J. & Anbar, A. D. Fe isotope fractionation during equilibration of Fe-organic complexes. Environ. Sci. Technol. 44, 60956101 (2010).
  37. Bruland, K. W., Orians, K. J. & Cowen, J. P. Reactive trace metals in the stratified central North Pacific. Geochim. Cosmochim. Acta 58, 31713182 (1994).
  38. Conway, T. M. & John, S. G. The cycling of iron, zinc and cadmium in the North East Pacific Ocean—insights from stable isotopes. Geochim. Cosmochim. Acta 164, 262283 (2015).
  39. Radic, A., Lacan, F. & Murray, J. W. Iron isotopes in the seawater of the equatorial Pacific Ocean: new constraints for the oceanic iron cycle. Earth Planet. Sci. Lett. 306, 110 (2011).
  40. Gledhill, M. & Buck, K. N. The organic complexation of iron in the marine environment: a review. Front. Microbiol. 3, 69 (2012).
  41. Dick, G. et al. The microbiology of deep-sea hydrothermal vent plumes: ecological and biogeographic linkages to seafloor and water column habitats. Front. Microbiol. 4, 124 (2013).
  42. Bennett, S. A. et al. Dissolved and particulate organic carbon in hydrothermal plumes from the East Pacific Rise, 9°50′N. Deep-Sea Res. I 58, 922931 (2011).
  43. Honjo, S., Manganini, S. J., Krishfield, R. A. & Francois, R. Particulate organic carbon fluxes to the ocean interior and factors controlling the biological pump: a synthesis of global sediment trap programs since 1983. Prog. Oceanogr. 76, 217285 (2008).
  44. Verdugo, P. et al. The oceanic gel phase: a bridge in the DOM–POM continuum. Mar. Chem. 92, 6785 (2004).
  45. Fitzsimmons, J. N. et al. Dissolved iron and iron isotopes in the Southeastern Pacific Ocean. Glob. Biogeochem. Cycles 30, 13721395 (2016).
  46. Goldberg, E. D. Marine Geochemistry 1. Chemical Scavengers of the Sea. J. Geol. 62, 249265 (1954).
  47. Koschinsky, A. & Hein, J. R. Uptake of elements from seawater by ferromanganese crusts: solid-phase associations and seawater speciation. Mar. Geol. 198, 331351 (2003).
  48. Völker, C. & Tagliabue, A. Modeling organic iron-binding ligands in a three-dimensional biogeochemical ocean model. Mar. Chem. 173, 6777 (2015).
  49. Parekh, P., Follows, M. J. & Boyle, E. Modeling the global ocean iron cycle. Glob. Biogeochem. Cycles 18, GB1002 (2004).
  50. Revels, B. N., Zhang, R., Adkins, J. F. & John, S. G. Fractionation of iron isotopes during leaching of natural particles by acidic and circumneutral leaches and development of an optimal leach for marine particulate iron isotopes. Geochim. Cosmochim. Acta 166, 92104 (2015).
  51. Cutter, G. A. & Bruland, K. W. Rapid and noncontaminating sampling system for trace elements in a global ocean surveys. Limnol. Oceanogr. 10, 425436 (2012).
  52. Planquette, H. & Sherrell, R. M. Sampling for particulate trace element determination using water sampling bottles: methodology and comparison to in situ pumps. Limnol. Oceanogr. 10, 367388 (2012).
  53. Fitzsimmons, J. N. & Boyle, E. A. Assessment and comparison of Anopore and cross flow filtration methods for the determination of dissolved iron size fractionation into soluble and colloidal phases in seawater. Limnol. Oceanogr. 12, 244261 (2014).
  54. Conway, T. M., Rosenberg, A. D., Adkins, J. F. & John, S. G. A new method for precise determination of iron, zinc, and cadmium stable isotope ratios in seawater by double-spike mass spectrometry. Anal. Chim. Acta 793, 4452 (2013).
  55. Lam, P. J., Ohnemus, D. C. & Auro, M. E. Size-fractionated major particle composition and concentrations from the US GEOTRACES North Atlantic Zonal Transect. Deep-Sea Res. II 116, 303320 (2015).
  56. McDonnell, A. M. P. et al. The oceanographic toolbox for the collection of sinking and suspended marine particles. Prog. Oceanogr. 133, 1731 (2015).
  57. Kilcoyne, A. L. D. et al. Interferometer-controlled scanning transmission X-ray microscopes at the Advanced Light Source. J. Synchrotron Radiat. 10, 125136 (2003).

Download references

Author information


  1. Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey 08901, USA

    • Jessica N. Fitzsimmons &
    • Robert M. Sherrell
  2. Department of Oceanography, Texas A&M University, College Station, Texas 77843, USA

    • Jessica N. Fitzsimmons
  3. Department of Earth Sciences, University of Southern California, Los Angeles, California 90089, USA

    • Seth G. John
  4. Department of Earth and Ocean Sciences, University of South Carolina, Columbia, South Carolina 29208, USA

    • Seth G. John &
    • Christopher M. Marsay
  5. Skidaway Institute of Oceanography, University of Georgia, Savannah, Georgia 31411, USA

    • Christopher M. Marsay
  6. Department of Earth Sciences, University of Minnesota—Twin Cities, Minneapolis, Minnesota 55455, USA

    • Colleen L. Hoffman &
    • Brandy M. Toner
  7. Department of Soil, Water, and Climate, University of Minnesota—Twin Cities, St Paul, Minnesota 55108, USA

    • Sarah L. Nicholas &
    • Brandy M. Toner
  8. Department of Earth and Ocean Sciences, National University of Ireland, Galway H91 TK33, Ireland

    • Sarah L. Nicholas
  9. Department of Geology & Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA

    • Christopher R. German
  10. Department of Earth and Planetary Sciences, Rutgers University, Piscataway, New Jersey 08854, USA

    • Robert M. Sherrell


J.N.F. determined the digested particulate metal concentrations, led data interpretation, and wrote the manuscript. R.M.S., C.R.G. and B.M.T. co-proposed the particulate studies. R.M.S., S.L.N. and C.R.G. collected samples on the GP16 cruise (C.R.G. as Chief Scientist). S.G.J. and C.M.M. made the Fe isotope measurements. C.L.H. and B.M.T. made the synchrotron measurements. All authors helped to refine the interpretation and contributed to manuscript revisions.

Competing financial interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to:

Author details

Supplementary information

PDF files

  1. Supplementary Information (748 KB)

    Supplementary Information

Additional data