Falkowski, P. & Raven, J. A. Aquatic Photosynthesis 488 (Princeton Univ. Press, 2007)
Ruud, J. T. Nitrates and phosphates in the Southern Seas. J. Conseil 5, 347–360 (1930)
Gran, H. H. On the conditions for the production of plankton in the sea. Conseil Permanent International pour l’Exploration de la Mer. Rapports et Procès-Verbaux des réunions 75, 37–46 (1931)
Hart, T. On the phytoplankton of the south-west Atlantic and the Bellingshausen Sea, 1929–31. Discov. Rep. VIII, 1–268 (1934)
Harvey, H. On the rate of diatom growth. J. Mar. Biol. Assoc. 19, 253–276 (1933)
Anderson, M. A. & Morel, F. M. M. The influence of aqueous iron chemistry on the uptake of iron by the coastal diatom Thalassiosira weissflogii. Limnol. Oceanogr. 27, 789–813 (1982)
Brand, L. E., Sunda, W. G. & Guillard, R. R. L. Limitation of marine phytoplankton reproductive rates by zinc, manganese and iron. Limnol. Oceanogr. 28, 1182–1198 (1983)
Cooper, L. H. N. Iron in the sea and in marine plankton. Proc. R. Soc. Lond. B 118, 419–438 (1935)
Goldberg, E. D. Marine geochemistry. 1. Chemical scavengers of the sea. J. Geol. 62, 249–265 (1954)
Williams, R. J. P. The Bakerian Lecture, 1981—Natural selection of the chemical elements. Proc. R. Soc. B 213, 361–397 (1981)
Raven, J. A. The iron and molybdenum use efficiencies of plant growth with different energy, carbon and nitrogen sources. New Phytol. 109, 279–287 (1988)
Moore, J. K., Doney, S. C., Glover, D. M. & Fung, I. Y. Iron cycling and nutrient-limitation patterns in surface waters of the World Ocean. Deep Sea Res. Part II 49, 463–507 (2002)
Bruland, K. W., Franks, R. P., Knauer, G. A. & Martin, J. H. Sampling and analytical methods for the determination of copper, cadmium, zinc, and nickel at the nanogram per liter level in sea water. Anal. Chim. Acta 105, 233–245 (1979)
Settle, D. & Patterson, C. Lead in albacore: guide to lead pollution in Americans. Science 207, 1167–1176 (1980)
Gordon, R. M., Martin, J. H. & Knauer, G. A. Iron in Northeast Pacific waters. Nature 299, 611–612 (1982)
Landing, W. M. & Bruland, K. W. The contrasting biogeochemistry of iron and manganese in the Pacific Ocean. Geochim. Cosmochim. Acta 51, 29–43 (1987)
Martin, J. H., Gordon, R. M. & Fitzwater, S. E. Iron in Antarctic waters. Nature 345, 156–158 (1990)
Martin, J. H., Fitzwater, S. E. & Gordon, R. M. Iron deficiency limits phytoplankton growth in Antarctic waters. Glob. Biogeochem. Cycles 4, 5–12 (1990)
Martin, J. H. Glacial-interglacial CO2 change: the iron hypothesis. Paleoceanography 5, 1–13 (1990).
This paper presented the iron hypothesis—that past variations in atmospheric carbon dioxide were driven by greater iron supply to the Southern Ocean.
Joos, F., Sarmiento, J. L. & Siegenthaler, U. Estimates of the effect of Southern Ocean iron fertilization on atmospheric CO2 concentrations. Nature 349, 772–775 (1991)
Cullen, J. J. Hypotheses to explain high-nutrient conditions in the open sea. Limnol. Oceanogr. 36, 1578–1599 (1991)
Martin, J. H. et al. Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean. Nature 371, 123–129 (1994)
Coale, K. H. et al. A massive phytoplankton bloom induced by an ecosystem-scale iron fertilization experiment in the equatorial Pacific Ocean. Nature 383, 495–501 (1996)
Boyd, P. W. et al. A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization. Nature 407, 695–702 (2000).
This paper reported results from the first in situ
iron fertilization experiment from the Southern Ocean.
Boyd, P. W. et al. Mesoscale iron enrichment experiments 1993–2005: synthesis and future directions. Science 315, 612–617 (2007)
de Baar, H. J. W. et al. Synthesis of iron fertilization experiments: from the Iron Age in the Age of Enlightenment. J. Geophys. Res. 110, C09S16 (2005)
Moore, C. M. et al. Iron limits primary productivity during spring bloom development in the central North Atlantic. Glob. Change Biol. 12, 626–634 (2006)
Hutchins, D. A., DiTullio, G. R., Zhang, Y. & Bruland, K. W. An iron limitation mosaic in the California upwelling regime. Limnol. Oceanogr. 43, 1037–1054 (1998)
Hutchins, D. A. et al. Phytoplankton iron limitation in the Humboldt Current and Peru Upwelling. Limnol. Oceanogr. 47, 997–1011 (2002)
Johnson, K. S., Gordon, R. M. & Coale, K. H. What controls dissolved iron concentrations in the world ocean? Mar. Chem. 57, 137–161 (1997).
This paper put forward the first conceptual and numerical model of the main processes driving the ocean iron cycle.
Gledhill, M. & van den Berg, C. M. G. Determination of complexation of iron(III) with natural organic complexing ligands in seawater using cathodic stripping voltammetry. Mar. Chem. 47, 41–54 (1994)
Rue, E. L. & Bruland, K. W. Complexation of iron(III) by natural organic ligands in the Central North Pacific as determined by a new competitive ligand equilibration/adsorptive cathodic stripping voltammetric method. Mar. Chem. 50, 117–138 (1995)
Sunda, W. G. & Huntsman, S. A. Interrelated influence of iron, light and cell size on marine phytoplankton growth. Nature 390, 389–392 (1997).
This paper demonstrated how different environmental factors led to large variations in the phytoplankton iron uptake.
Archer, D. E. & Johnson, K. A model of the iron cycle in the ocean. Glob. Biogeochem. Cycles 14, 269–279 (2000)
Parekh, P., Follows, M. J. & Boyle, E. A. Decoupling of iron and phosphate in the global ocean. Glob. Biogeochem. Cycles 19, GB2020 (2005)
Jickells, T. D. et al. Global iron connections between desert dust, ocean biogeochemistry, and climate. Science 308, 67–71 (2005)
de Baar, H. J. & de Jong, J. T. in The Biogeochemistry of Iron in Seawater Vol. 7 (eds Turner, D. R. & Hunter, K. A.) 123–254 (2001)
Tagliabue, A. et al. How well do global ocean biogeochemistry models simulate dissolved iron distributions? Glob. Biogeochem. Cycles 30, 149–174 (2016).
This paper was the first to critically appraise how well a range of state-of-the-art ocean models represented the ocean iron cycle.
Hain, M. P., Sigman, D. M. & Haug, G. H. Carbon dioxide effects of Antarctic stratification, North Atlantic Intermediate Water formation, and subantarctic nutrient drawdown during the last ice age: Diagnosis and synthesis in a geochemical box model. Glob. Biogeochem. Cycles 24, GB4023 (2010)
Watson, A. J., Bakker, D. C. E., Ridgwell, A. J., Boyd, P. W. & Law, C. S. Effect of iron supply on Southern Ocean CO2 uptake and implications for glacial atmospheric CO2. Nature 407, 730–733 (2000)
The GEOTRACES Group. The GEOTRACES Intermediate Data Product 2014. Mar. Chem. 177, 1–8 (2015).
This paper reported the first release of high-quality iron data, alongside a range of other important datasets, from the GEOTRACES programme.
Anderson, R. & Henderson, G. GEOTRACES—A global study of the marine biogeochemical cycles of trace elements and their isotopes. Oceanography 18, 76–79 (2005)
Johnson, K. S. et al. Developing standards for dissolved iron in seawater. Eos 88, 131–132 (2007)
Boyd, P. W. et al. FeCycle: attempting an iron biogeochemical budget from a mesoscale SF6 tracer experiment in unperturbed low iron waters. Glob. Biogeochem. Cycles 19, GB4S20 (2005)
Blain, S. et al. Effect of natural iron fertilization on carbon sequestration in the Southern Ocean. Nature 446, 1070–1074 (2007)
Pollard, R. T. et al. Southern Ocean deep-water carbon export enhanced by natural iron fertilization. Nature 457, 577–580 (2009)
Elrod, V. A., Berelson, W. M., Coale, K. H. & Johnson, K. S. The flux of iron from continental shelf sediments: a missing source for global budgets. Geophys. Res. Lett. 31, L12307 (2004)
Lam, P. J. & Bishop, J. K. B. The continental margin is a key source of iron to the HNLC North Pacific Ocean. Geophys. Res. Lett. 35, L07608 (2008)
Tagliabue, A., Aumont, O. & Bopp, L. The impact of different external sources of iron on the global carbon cycle. Geophys. Res. Lett. 41, 920–926 (2014)
Saito, M. A. et al. Slow-spreading submarine ridges in the South Atlantic as a significant oceanic iron source. Nat. Geosci. 6, 775–779 (2013)
Resing, J. A. et al. Basin-scale transport of hydrothermal dissolved metals across the South Pacific Ocean. Nature 523, 200–203 (2015).
This paper was the first to demonstrate that the longevity of iron from hydrothermal vents was much longer than previously estimated.
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. Part II 58, 2678–2694 (2011)
Klunder, M. B. et al. Dissolved iron in the Arctic shelf seas and surface waters of the central Arctic Ocean: impact of Arctic river water and ice-melt. J. Geophys. Res. Oceans 117, C01027 (2012)
Tagliabue, A. et al. Hydrothermal contribution to the oceanic dissolved iron inventory. Nat. Geosci. 3, 252–256 (2010)
Martinez-Garcia, A. et al. Iron fertilization of the Subantarctic ocean during the last ice age. Science 343, 1347–1350 (2014)
Jaccard, S. L., Galbraith, E. D., Martinez-Garcia, A. & Anderson, R. F. Covariation of deep Southern Ocean oxygenation and atmospheric CO2 through the last ice age. Nature 530, 207–210 (2016)
Sigman, D. M., Hain, M. P. & Haug, G. H. The polar ocean and glacial cycles in atmospheric CO2 concentration. Nature 466, 47–55 (2010)
Lambert, F. et al. Dust fluxes and iron fertilization in Holocene and Last Glacial Maximum climates. Geophys. Res. Lett. 42, 6014–6023 (2015)
Conway, T. M. & John, S. G. Quantification of dissolved iron sources to the North Atlantic Ocean. Nature 511, 212–215 (2014).
This paper was the first to use iron isotopes to fingerprint the importance of different iron sources in the North Atlantic Ocean.
Moore, C. M. et al. Processes and patterns of oceanic nutrient limitation. Nat. Geosci. 6, 701–710 (2013)
Falkowski, P. G. Evolution of the nitrogen cycle and its influence on the biological sequestration of CO2 in the ocean. Nature 387, 272–275 (1997)
Moore, C. M. et al. Large-scale distribution of Atlantic nitrogen fixation controlled by iron availability. Nat. Geosci. 2, 867–871 (2009)
Schlosser, C. et al. Seasonal ITCZ migration dynamically controls the location of the (sub)tropical Atlantic biogeochemical divide. Proc. Natl Acad. Sci. USA 111, 1438–1442 (2014)
Dutkiewicz, S., Ward, B. A., Monteiro, F. & Follows, M. J. Interconnection of nitrogen fixers and iron in the Pacific Ocean: theory and numerical simulations. Glob. Biogeochem. Cycles 26, GB1012 (2012)
Weber, T. & Deutsch, C. Local versus basin-scale limitation of marine nitrogen fixation. Proc. Natl Acad. Sci. USA 111, 8741–8746 (2014)
Gledhill, M. & Buck, K. N. The organic complexation of iron in the marine environment: a review. Front. Microbiol. 3, 69 (2012)
Boyd, P. W. & Tagliabue, A. Using the L* concept to explore controls on the relationship between paired ligand and dissolved iron concentrations in the ocean. Mar. Chem. 173, 52–66 (2015)
Buck, K. N., Sohst, B. & Sedwick, P. N. The organic complexation of dissolved iron along the U.S. GEOTRACES (GA03) North Atlantic Section. Deep Sea Res. Part II 116, 152–165 (2015)
Gerringa, L. J. A., Rijkenberg, M. J. A., Schoemann, V., Laan, P. & de Baar, H. J. W. Organic complexation of iron in the West Atlantic Ocean. Mar. Chem. 177, 434–446 (2015)
Wozniak, A. S., Shelley, R. U., McElhenie, S. D., Landing, W. M. & Hatcher, P. G. Aerosol water soluble organic matter characteristics over the North Atlantic Ocean: implications for iron-binding ligands and iron solubility. Mar. Chem. 173, 162–172 (2015)
Cheize, M. et al. Iron organic speciation determination in rainwater using cathodic stripping voltammetry. Anal. Chim. Acta 736, 45–54 (2012)
Mawji, E. et al. Production of siderophore type chelates in Atlantic Ocean waters enriched with different carbon and nitrogen sources. Mar. Chem. 124, 90–99 (2011)
Tagliabue, A., Williams, R. G., Rogan, N., Achterberg, E. P. & Boyd, P. W. A ventilation-based framework to explain the regeneration-scavenging balance of iron in the ocean. Geophys. Res. Lett. 41, 7227–7236 (2014)
Völker, C. & Tagliabue, A. Modeling organic iron-binding ligands in a three-dimensional biogeochemical ocean model. Mar. Chem. 173, 67–77 (2015)
Twining, B. S. & Baines, S. B. The trace metal composition of marine phytoplankton. Annu. Rev. Mar. Sci. 5, 191–215 (2013).
This paper provides a state-of-the-art summary of the iron content of marine phytoplankton determined using a variety of different techniques.
Twining, B. S., Rauschenberg, S., Morton, P. L. & Vogt, S. Metal contents of phytoplankton and labile particulate material in the North Atlantic Ocean. Prog. Oceanogr. 137, 261–283 (2015)
Martiny, A. C. et al. Strong latitudinal patterns in the elemental ratios of marine plankton and organic matter. Nat. Geosci. 6, 279–283 (2013)
Boyd, P. W. et al. Why are biotic iron pools uniform across high- and low-iron pelagic ecosystems? Glob. Biogeochem. Cycles 29, 1028–1043 (2015)
Bowie, A. R. et al. Iron budgets for three distinct biogeochemical sites around the Kerguelen Archipelago (Southern Ocean) during the natural fertilisation study, KEOPS-2. Biogeosciences 12, 4421–4445 (2015)
Ratnarajah, L., Bowie, A. R., Lannuzel, D., Meiners, K. M. & Nicol, S. The biogeochemical role of baleen whales and krill in Southern Ocean nutrient cycling. PLoS One 9, e114067 (2014); correction 10(4), e0125134 (2015)
Twining, B. S. et al. Differential remineralization of major and trace elements in sinking diatoms. Limnol. Oceanogr. 59, 689–704 (2014)
Tagliabue, A. et al. Surface-water iron supplies in the Southern Ocean sustained by deep winter mixing. Nat. Geosci. 7, 314–320 (2014)
Hudson, R. J. M. & Morel, F. M. M. Iron transport in marine phytoplankton: kinetics of cellular and medium coordination reactions. Limnol. Oceanogr. 35, 1002–1020 (1990)
Morel, F. M. M., Kustka, A. B. & Shaked, Y. The role of unchelated Fe in the iron nutrition of phytoplankton. Limnol. Oceanogr. 53, 400–404 (2008)
Schlosser, C., De La Rocha, C. L., Streu, P. & Croot, P. L. Solubility of iron in the Southern Ocean. Limnol. Oceanogr. 57, 684–697 (2012)
Liu, X. & Millero, F. J. The solubility of iron in seawater. Mar. Chem. 77, 43–54 (2002)
Tagliabue, A. & Arrigo, K. R. Processes governing the supply of iron to phytoplankton in stratified seas. J. Geophys. Res. 111, C06019 (2006)
Weber, L., Völker, C., Schartau, M. & Wolf-Gladrow, D. A. Modeling the speciation and biogeochemistry of iron at the Bermuda Atlantic Time-series Study site. Glob. Biogeochem. Cycles 19, GB1019 (2005)
Croot, P. L. et al. Retention of dissolved iron and Fe-II in an iron induced Southern Ocean phytoplankton bloom. Geophys. Res. Lett. 28, 3425–3428 (2001)
Moffett, J. W., Goepfert, T. J. & Naqvi, S. W. A. Reduced iron associated with secondary nitrite maxima in the Arabian Sea. Deep Sea Res. Part I 54, 1341–1349 (2007)
Sedwick, P. N., Sohst, B. M., Ussher, S. J. & Bowie, A. R. A zonal picture of the water column distribution of dissolved iron(II) during the U.S. GEOTRACES North Atlantic transect cruise (GEOTRACES GA03). Deep Sea Res. Part II 116, 166–175 (2015)
Strzepek, R. F., Maldonado, M. T., Hunter, K. A., Frew, R. D. & Boyd, P. W. Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: uptake of organically complexed iron and reduced cellular iron requirements. Limnol. Oceanogr. 56, 1983–2002 (2011)
Maldonado, M. T. & Price, N. M. Utilization of iron bound to strong organic ligands by plankton communities in the subarctic Pacific Ocean. Deep Sea Res. Part II 46, 2447–2473 (1999)
Rubin, M., Berman-Frank, I. & Shaked, Y. Dust- and mineral-iron utilization by the marine dinitrogen-fixer Trichodesmium. Nat. Geosci. 4, 529–534 (2011)
Shaked, Y., Kustka, A. B. & Morel, F. M. M. A general kinetic model for iron acquisition by eukaryotic phytoplankton. Limnol. Oceanogr. 50, 872–882 (2005)
Lis, H., Shaked, Y., Kranzler, C., Keren, N. & Morel, F. M. Iron bioavailability to phytoplankton: an empirical approach. ISME J. 9, 1003–1013 (2014)
Saito, M. A. et al. Multiple nutrient stresses at intersecting Pacific Ocean biomes detected by protein biomarkers. Science 345, 1173–1177 (2014).
This paper was the first to link data on resource stress from proteomic to field measurements of resource concentrations to demonstrate the transitions between iron and nitrogen limitation in the Pacific Ocean
Rijkenberg, M. J. et al. The distribution of dissolved iron in the West Atlantic Ocean. PLoS One 9, e101323 (2014)
Dutkiewicz, S., Follows, M. J. & Parekh, P. Interactions of the iron and phosphorus cycles: a three-dimensional model study. Global Biogeochem. Cycles 19, GB1021 (2005)
Wagener, T., Guieu, C. & Leblond, N. Effects of dust deposition on iron cycle in the surface Mediterranean Sea: results from a mesocosm seeding experiment. Biogeosciences 7, 3769–3781 (2010)
Sohm, J. A. et al. Nitrogen fixation in the South Atlantic Gyre and the Benguela Upwelling System. Geophys. Res. Lett. 38, L16608 (2011)
Boyd, P. W. & Ellwood, M. J. The biogeochemical cycle of iron in the ocean. Nat. Geosci. 3, 675–682 (2010)
Slemons, L. O., Murray, J. W., Resing, J., Paul, B. & Dutrieux, P. Western Pacific coastal sources of iron, manganese, and aluminum to the Equatorial Undercurrent. Glob. Biogeochem. Cycles 24, GB3024 (2010)
Nishioka, J. et al. Iron supply to the western subarctic Pacific: importance of iron export from the Sea of Okhotsk. J. Geophys. Res. 112, C10012 (2007)
Tagliabue, A. et al. Quantifying the roles of ocean circulation and biogeochemistry in governing ocean carbon-13 and atmospheric carbon dioxide at the last glacial maximum. Clim. Past 5, 695–706 (2009)
Middleton, J. L., Langmuir, C. H., Mukhopadhyay, S., McManus, J. F. & Mitrovica, J. X. Hydrothermal iron flux variability following rapid sea level changes. Geophys. Res. Lett. 43, 3848–3856 (2016)
Lund, D. C. et al. Enhanced East Pacific Rise hydrothermal activity during the last two glacial terminations. Science 351, 478–482 (2016)
Bopp, L. et al. Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models. Biogeosciences 10, 6225–6245 (2013)
Charette, M. A., Morris, P. J., Henderson, P. B. & Moore, W. S. Radium isotope distributions during the US GEOTRACES North Atlantic cruises. Mar. Chem. 177, 184–195 (2015)
Wu, J., Boyle, E., Sunda, W. & Wen, L. S. Soluble and colloidal iron in the oligotrophic North Atlantic and North Pacific. Science 293, 847–849 (2001)
von der Heyden, B. P., Roychoudhury, A. N., Mtshali, T. N., Tyliszczak, T. & Myneni, S. C. Chemically and geographically distinct solid-phase iron pools in the Southern Ocean. Science 338, 1199–1201 (2012)
Tortell, P. D., Maldonado, M. T. & Price, N. M. The role of heterotrophic bacteria in iron-limited ocean ecosystems. Nature 383, 330–332 (1996)
Bonnain, C., Breitbart, M. & Buck, K. N. The Ferrojan horse hypothesis: iron-virus interactions in the ocean. Front. Mar. Sci. 3, https://doi.org/10.3389/fmars.2016.00082 (2016)
Mackey, K. R. et al. Divergent responses of Atlantic coastal and oceanic Synechococcus to iron limitation. Proc. Natl Acad. Sci. USA 112, 9944–9949 (2015)
Hogle, S. L., Barbeau, K. A. & Gledhill, M. Heme in the marine environment: from cells to the iron cycle. Metallomics 6, 1107–1120 (2014)
Jenkins, W. J., Smethie, W. M., Boyle, E. A. & Cutter, G. A. Water mass analysis for the U.S. GEOTRACES (GA03) North Atlantic sections. Deep Sea Res. Part II 116, 6–20 (2015)
Ito, T. & Follows, M. J. Preformed phosphate, soft tissue pump and atmospheric CO2. J. Mar. Res. 63, 813–839 (2005)
Broecker, W. S., Takahashi, T. & Takahashi, T. Sources and flow patterns of deep-ocean waters as deduced from potential temperature, salinity, and initial phosphate concentration. J. Geophys. Res. 90, 6925–6939 (1985)
Duteil, O. et al. A novel estimate of ocean oxygen utilisation points to a reduced rate of respiration in the ocean interior. Biogeosciences 10, 7723–7738 (2013)
Waugh, D. W., Primeau, F., Devries, T. & Holzer, M. Recent changes in the ventilation of the southern oceans. Science 339, 568–570 (2013)