Trace elements sustain biological productivity, yet the significance of trace element mobilization and export in subglacial runoff from ice sheets is poorly constrained at present. Here, we present size-fractionated (0.02, 0.22, and 0.45 µm) concentrations of trace elements in subglacial waters from the Greenland Ice Sheet (GrIS) and the Antarctic Ice Sheet (AIS). Concentrations of immobile trace elements (e.g., Al, Fe, Ti) far exceed global riverine and open ocean mean values and highlight the importance of subglacial aluminosilicate mineral weathering and lack of retention of these species in sediments. Concentrations are higher from the AIS than the GrIS, highlighting the geochemical consequences of prolonged water residence times and hydrological isolation that characterize the former. The enrichment of trace elements (e.g., Co, Fe, Mn, and Zn) in subglacial meltwaters compared with seawater and typical riverine systems, together with the likely sensitivity to future ice sheet melting, suggests that their export in glacial runoff is likely to be important for biological productivity. For example, our dissolved Fe concentration (20,900 nM) and associated flux values (1.4 Gmol y-1) from AIS to the Fe-deplete Southern Ocean exceed most previous estimates by an order of magnitude. The ultimate fate of these micronutrients will depend on the reactivity of the dominant colloidal size fraction (likely controlled by nanoparticulate Al and Fe oxyhydroxide minerals) and estuarine processing. We contend that ice sheets create highly geochemically reactive particulates in subglacial environments, which play a key role in trace elemental cycles, with potentially important consequences for global carbon cycling.

Department of Earth and Environmental Sciences University of Minnesota Minneapolis MN 55455

Department of Earth Sciences Montana State University Bozeman MT 59717

Department of Ecology Faculty of Science Charles University CZ 12844 Prague Czechia

Department of Land Resources and Environmental Sciences Bozeman Montana State University MT 59717

Interface Geochemistry German Research Centre for Geosciences 14473 Potsdam Germany

National High Magnetic Field Laboratory Geochemistry Group Department of Earth Ocean and Atmospheric Sciences Florida State University Tallahassee FL 32306

National High Magnetic Field Laboratory Geochemistry Group Department of Earth Ocean and Atmospheric Sciences Florida State University Tallahassee FL 32306;

School of Earth and Ocean Sciences Cardiff University Cardiff CF10 3AT United Kingdom

School of Earth Sciences Byrd Polar and Climate Research Center The Ohio State University Columbus OH 43210

School of Earth Sciences University of Bristol Bristol BS8 1RL United Kingdom

School of Geographical Sciences University of Bristol Bristol BS8 1SS United Kingdom

Stream Biofilm and Ecosystem Research Laboratory School of Architecture Civil and Environmental Engineering École Polytechnique Fédérale de Lausanne Lausanne CH 1015 Switzerland

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Wadham J. L., et al. , Ice sheets matter for the global carbon cycle. Nat. Commun. 10, 3567 (2019). PubMed PMC

Bamber J. L., Westaway R. M., Marzeion B., Wouters B., The land ice contribution to sea level during the satellite era. Environ. Res. Lett. 13, 063008 (2018).

Smith B., et al. , Pervasive ice sheet mass loss reflects competing ocean and atmosphere processes. Science 368, 1239–1242 (2020). PubMed

Ashmore D. W., Bingham R. G., Antarctic subglacial hydrology: Current knowledge and future challenges. Antarct. Sci. 26, 758–773 (2014).

Siegert M. J., Ross N., Le Brocq A. M., Recent advances in understanding Antarctic subglacial lakes and hydrology. Philos. Trans. R. Soc. A 374, 20140306 (2016). PubMed PMC

Bowling J. S., Livingstone S. J., Sole A. J., Chu W., Distribution and dynamics of Greenland subglacial lakes. Nat. Commun. 10, 2810 (2019). PubMed PMC

Carter S. P., Fricker H. A., The supply of subglacial meltwater to the grounding line of the Siple Coast, West Antarctica. Ann. Glaciol. 53, 267–280 (2012).

Priscu J. C., et al. , “Antarctic subglacial water: Origin, evolution, and ecology” in Polar Lakes and Rivers, Vincent W. F., Laybourn-Parry J., Eds. (Oxford University Press, Oxford, United Kingdom, 2008), vol. 1, pp. 119–137.

Urra A., et al. , Weathering dynamics under contrasting Greenland ice sheet catchments. Front. Earth Sci. 7, 299 (2019).

Sharp M., Tranter M., Glacier biogeochemistry. Geochem. Perspect. 6, 173–339 (2017).

Cowton T., Nienow P., Bartholomew I., Sole A., Mair D., Rapid erosion beneath the Greenland ice sheet. Geology 40, 343–346 (2012).

Tranter M., Wadham J. L., “Geochemical weathering in glacial and proglacial environments” in Treatise on Geochemistry, Turekian H. D., Holland K. K., Eds. (Elsevier, Oxford, United Kingdom, ed. 2, 2014), pp. 157–173.

Hawkings J. R., et al. , The effect of warming climate on nutrient and solute export from the Greenland Ice Sheet. Geochem. Perspect. Lett. 1, 94–104 (2015).

Hood E., Battin T. J., Fellman J., O’Neel S., Spencer R. G. M., Storage and release of organic carbon from glaciers and ice sheets. Nat. Geosci. 8, 91–96 (2015).

Vick-Majors T. J., et al. , Biogeochemical connectivity between freshwater ecosystems beneath the West Antarctic ice sheet and the sub-ice marine environment. Global Biogeochem. Cycle 34, e2019GB006446 (2020).

Yde J. C., Knudsen N. T., Hasholt B., Mikkelsen A. B., Meltwater chemistry and solute export from a Greenland ice sheet catchment, Watson River, West Greenland. J. Hydrol. 519, 2165–2179 (2014).

Priscu J. C., et al. , A microbiologically clean strategy for access to the Whillans Ice Stream subglacial environment. Antarct. Sci. 25, 637–647 (2013).

Michaud A. B., et al. , Environmentally clean access to Antarctic subglacial aquatic environments. Antarct. Sci. 32, 329–340 (2020).

Hopwood M. J., et al. , Review article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic? Cryosphere 14, 1347–1383 (2020).

Mitchell A. C., Brown G. H., Diurnal hydrological–physicochemical controls and sampling methods for minor and trace elements in an Alpine glacial hydrological system. J. Hydrol. (Amst.) 332, 123–143 (2007).

Aciego S. M., Stevenson E. I., Arendt C. A., Climate versus geological controls on glacial meltwater micronutrient production in southern Greenland. Earth Planet. Sci. Lett. 424, 51–58 (2015).

Gaillardet J., Viers J., Dupre B., “7.7 - Trace elements in river waters” in Treatise on Geochemistry (second edition), Holland H. D., Turekian K. K., Eds. (Elsevier, Oxford, UK, 2014), vol. 5, pp. 195–235.

Hawkings J. R., et al. , Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans. Nat. Commun. 5, 3929 (2014). PubMed PMC

Gardner C. B., et al. , Molybdenum, vanadium, and uranium weathering in small mountainous rivers and rivers draining high-standing islands. Geochim. Cosmochim. Acta 219, 22–43 (2017).

Shiller A. M., Mao L., Dissolved vanadium in rivers: Effects of silicate weathering. Chem. Geol. 165, 13–22 (2000).

Miller C. A., Peucker-Ehrenbrink B., Walker B. D., Marcantonio F., Re-assessing the surface cycling of molybdenum and rhenium. Geochim. Cosmochim. Acta 75, 7146–7179 (2011).

Cullen J. T., Maldonado M. T., “Biogeochemistry of cadmium and its release to the environment” in Cadmium: From Toxicity to Essentiality, Sigel A., Sigel H., Sigel R. K. O., Eds. (Springer Netherlands, Dordrecht, the Netherlands, 2013), pp. 31–62. PubMed

Shiller A. M., Dissolved trace elements in the Mississippi River: Seasonal, interannual, and decadal variability. Geochim. Cosmochim. Acta 61, 4321–4330 (1997).

Benjamin M. M., Leckie J. O., Multiple-site adsorption of Cd, Cu, Zn, and Pb on amorphous iron oxyhydroxide. J. Colloid Interface Sci. 79, 209–221 (1981).

Palmer M. R., Edmond J. M., Uranium in river water. Geochim. Cosmochim. Acta 57, 4947–4955 (1993).

Palmer M. R., Edmond J. M., The strontium isotope budget of the modern ocean. Earth Planet. Sci. Lett. 92, 11–26 (1989).

Morel F. M. M., Milligan A. J., Saito M. A., “8.5–Marine bioinorganic chemistry: The role of trace metals in the oceanic cycles of major nutrients” in Treatise on Geochemistry, Holland H. D., Turekian K. K., Eds. (Elsevier, Oxford, United Kingdom, ed. 2, 2014), pp. 123–150.

Lohan M. C., Tagliabue A., Oceanic micronutrients: Trace metals that are essential for marine life. Elements 14, 385–390 (2018).

Twining B. S., Baines S. B., The trace metal composition of marine phytoplankton. Annu. Rev. Mar. Sci. 5, 191–215 (2013). PubMed

Moore C. M., et al. , Processes and patterns of oceanic nutrient limitation. Nat. Geosci. 6, 701–710 (2013).

Downs T. M., Schallenberg M., Burns C. W., Responses of lake phytoplankton to micronutrient enrichment: A study in two New Zealand lakes and an analysis of published data. Aquat. Sci. 70, 347–360 (2008).

Graly J. A., Humphrey N. F., Landowski C. M., Harper J. T., Chemical weathering under the Greenland ice sheet. Geology 42, 551–554 (2014).

Michaud A. B., et al. , Solute sources and geochemical processes in subglacial lake Whillans, west Antarctica. Geology 44, 347–350 (2016).

Le Brocq A., et al. , Evidence from ice shelves for channelized meltwater flow beneath the Antarctic Ice Sheet. Nat. Geosci. 6, 945–948 (2013).

Hawkings J. R., et al. , Biolabile ferrous iron bearing nanoparticles in glacial sediments. Earth Planet. Sci. Lett. 493, 92–101 (2018).

Raiswell R., et al. , Iron in glacial systems: Speciation, reactivity, freezing behavior, and alteration during transport. Front. Earth Sci. 6, 222 (2018).

Siegfried M. R., Fricker H. A., Thirteen years of subglacial lake activity in Antarctica from multi-mission satellite altimetry. Ann. Glaciol. 59, 42–55 (2018).

Martin J. M., Meybeck M., Elemental mass-balance of material carried by major world rivers. Mar. Chem. 7, 173–206 (1979).

Hatton J. E., et al. , Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes. Geochim. Cosmochim. Acta 247, 191–206 (2019).

Kellerman A. M., et al. , Glacier outflow dissolved organic matter as a window into seasonally changing carbon sources: Leverett Glacier, Greenland. J. Geophys. Res. Biogeosci. 125, e2019JG005161 (2020).

Hawkings J. R., et al. , Ice sheets as a missing source of silica to the polar oceans. Nat. Commun. 8, 14198 (2017). PubMed PMC

Durr H. H., Meybeck M., Hartmann J., Laruelle G. G., Roubeix V., Global spatial distribution of natural riverine silica inputs to the coastal zone. Biogeosciences 8, 597–620 (2011).

Rudnick R. L., Gao S., “Composition of the continental crust” in Treatise on Geochemistry, Holland H. D., Turekian K. K., Eds. (Elsevier, Oxford, United Kingdom, ed. 2, 2014), pp. 1–51.

Wadham J. L., et al. , Biogeochemical weathering under ice: Size matters. Global Biogeochem. Cycle 24, GB3025 (2010).

Hindshaw R. S., Rickli J., Leuthold J., Wadham J., Bourdon B., Identifying weathering sources and processes in an outlet glacier of the Greenland Ice Sheet using Ca and Sr isotope ratios. Geochim. Cosmochim. Acta 145, 50–71 (2014).

Stevenson E. I., Fantle M. S., Das S. B., Williams H. M., Aciego S. M., The iron isotopic composition of subglacial streams draining the Greenland Ice Sheet. Geochim. Cosmochim. Acta 213, 237–254 (2017).

Barrón V., Torrent J., “9. - Iron, manganese and aluminium oxides and oxyhydroxides” in Minerals at the Nanoscale, Nieto F., Livi K. J. T., Oberti R., Eds. (Mineralogical Society of Great Britain and Ireland, Twickenham, UK, 2013), pp. 295–334.

Olivié-Lauquet G., Allard T., Bertaux J., Muller J.-P., Crystal chemistry of suspended matter in a tropical hydrosystem, Nyong basin (Cameroon, Africa). Chem. Geol. 170, 113–131 (2000).

Stegemeier J. P., Reinsch B. C., Lentini C. J., Dale J. G., Kim C. S., Aggregation of nanoscale iron oxyhydroxides and corresponding effects on metal uptake, retention, and speciation. II. Temperature and time. Geochim. Cosmochim. Acta 148, 113–129 (2015).

Dale J. G., Stegemeier J. P., Kim C. S., Aggregation of nanoscale iron oxyhydroxides and corresponding effects on metal uptake, retention, and speciation. I. Ionic-strength and pH. Geochim. Cosmochim. Acta 148, 100–112 (2015).

Hochella M. F. Jr. et al. , Nanominerals, mineral nanoparticles, and Earth systems. Science 319, 1631–1635 (2008). PubMed

Pryer H., et al. , The Effects of Glacial Cover on Riverine Silicon Isotope Compositions in Chilean Patagonia. Frontiers in Earth Science. DOI: 10.3389/feart.2020.00368, in press. DOI

Beaton A. D., et al. , High-resolution in situ measurement of nitrate in runoff from the Greenland ice sheet. Environ. Sci. Technol. 51, 12518–12527 (2017). PubMed

Wadham J., et al. , The potential role of the Antarctic Ice Sheet in global biogeochemical cycles. Earth Environ. Sci. Trans. R. Soc. Edinburgh 104, 55–67 (2013).

Ulrich K.-U., Rossberg A., Foerstendorf H., Zänker H., Scheinost A. C., Molecular characterization of uranium(VI) sorption complexes on iron(III)-rich acid mine water colloids. Geochim. Cosmochim. Acta 70, 5469–5487 (2006).

Markich S. J., Uranium speciation and bioavailability in aquatic systems: An overview. ScientificWorldJournal 2, 707–729 (2002). PubMed PMC

Saeki K., Wada S.-I., Shibata M., Ca2+-Fe2+ and Ca2+-Mn2+ exchange selectivitiy of kaolinite, montmorillonite, and illite. Soil Sci. 169, 125–132 (2004).

Chandler D. M., et al. , Evolution of the subglacial drainage system beneath the Greenland Ice Sheet revealed by tracers. Nat. Geosci. 6, 195–198 (2013).

Lamarche-Gagnon G., et al. , Greenland melt drives continuous export of methane from the ice-sheet bed. Nature 565, 73–77 (2019). PubMed

Pankow J. F., Morgan J. J., Kinetics for the aquatic environment–manganese. Environ. Sci. Technol. 15, 1306–1313 (1981). PubMed

Cody R. D., Adsorption and the reliability of trace elements as environment indicators for shales. J. Sediment. Res. 41, 461–471 (1971).

Kohler T. J., et al. , Carbon dating reveals a seasonal progression in the source of particulate organic carbon exported from the Greenland Ice Sheet. Geophys. Res. Lett. 44, 6209–6217 (2017).

Tagliabue A., et al. , The role of external inputs and internal cycling in shaping the global ocean cobalt distribution: Insights from the first cobalt biogeochemical model. Global Biogeochem. Cycles 32, 594–616 (2018). PubMed PMC

Bhatia M. P., et al. , Greenland meltwater as a significant and potentially bioavailable source of iron to the ocean. Nat. Geosci. 6, 274–278 (2013).

Statham P. J., Skidmore M., Tranter M., Inputs of glacially derived dissolved and colloidal iron to the coastal ocean and implications for primary productivity. Global Biogeochem. Cycle 22, GB3013 (2008).

Hodson A., et al. , Climatically sensitive transfer of iron to maritime Antarctic ecosystems by surface runoff. Nat. Commun. 8, 14499 (2017). PubMed PMC

van der Merwe P., et al. , High lability Fe particles sourced from glacial erosion can meet previously unaccounted biological demand: Heard Island, Southern Ocean. Front. Mar. Sci. 6, 332 (2019).

Hopwood M. J., et al. , Highly variable iron content modulates iceberg-ocean fertilisation and potential carbon export. Nat. Commun. 10, 5261 (2019). PubMed PMC

Raiswell R., et al. , Potentially bioavailable iron delivery by iceberg-hosted sediments and atmospheric dust to the polar oceans. Biogeosciences 13, 3887–3900 (2016).

Dai A., Trenberth K. E., Estimates of freshwater discharge from continents: Latitudinal and seasonal variations. J. Hydrometeorol. 3, 660–687 (2002).

Hopwood M. J., et al. , Seasonal changes in Fe along a glaciated Greenlandic fjord. Front. Earth Sci. 4, 15 (2016).

Schroth A. W., Crusius J., Hoyer I., Campbell R., Estuarine removal of glacial iron and implications for iron fluxes to the ocean. Geophys. Res. Lett. 41, 3951–3958 (2014).

Wadham J. L., et al. , Sources, cycling and export of nitrogen on the Greenland Ice Sheet. Biogeosciences 13, 6339–6352 (2016).

Hawkings J., et al. , The Greenland Ice Sheet as a hotspot of phosphorus weathering and export in the Arctic. Global Biogeochem. Cycles 30, 191–210 (2016).

Bruland K. W., Middag R., Lohan M. C., “Controls of trace metals in seawater” in Treatise on Geochemistry, Holland H. D., Turekian K. K., Eds. (Elsevier, Oxford, United Kingdom, ed. 2, 2014), pp. 19–51.

Bruland K. W., et al. , Factors influencing the chemistry of the near-field Columbia River plume: Nitrate, silicic acid, dissolved Fe, and dissolved Mn. J. Geophys. Res. Oceans 113, C00B02 (2008).

Meire L., et al. , Marine-terminating glaciers sustain high productivity in Greenland fjords. Glob. Change Biol. 23, 5344–5357 (2017). PubMed

Arrigo K. R., van Dijken G. L., Strong A. L., Environmental controls of marine productivity hot spots around Antarctica. J. Geophys. Res. Oceans 120, 5545–5565 (2015).

van Hulten M., et al. , Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese. Biogeosciences 14, 1123–1152 (2017).

Richon C., Tagliabue A., Insights into the major processes driving the global distribution of copper in the ocean from a global model. Global Biogeochem. Cycles 33, 1594–1610 (2019). PubMed PMC

Martin J. H., Fitzwater S. E., Gordon R. M., Iron deficiency limits phytoplankton growth in Antarctic waters. Global Biogeochem. Cycles 4, 5–12 (1990).

Annett A. L., et al. , Controls on dissolved and particulate iron distributions in surface waters of the Western Antarctic Peninsula shelf. Mar. Chem. 196, 81–97 (2017).

Gerringa L. J. A., et al. , Iron from melting glaciers fuels the phytoplankton blooms in Amundsen Sea (Southern Ocean): Iron biogeochemistry. Deep Sea Res. Part II Top Stud. Oceanogr. 71-76, 16–31 (2012).

Death R., et al. , Antarctic ice sheet fertilises the Southern Ocean. Biogeosciences 11, 2635–2643 (2014).

Person R., et al. , Sensitivity of ocean biogeochemistry to the iron supply from the Antarctic Ice Sheet explored with a biogeochemical model. Biogeosciences 16, 3583–3603 (2019).

Pattyn F., Antarctic subglacial conditions inferred from a hybrid ice sheet/ice stream model. Earth Planet. Sci. Lett. 295, 451–461 (2010).

Shiller A. M., Syringe filtration methods for examining dissolved and colloidal trace element distributions in remote field locations. Environ. Sci. Technol. 37, 3953–3957 (2003). PubMed

Laufkötter C., Stern A. A., John J. G., Stock C. A., Dunne J. P., Glacial iron sources stimulate the Southern Ocean carbon cycle. Geophys. Res. Lett. 45, 13377–13385 (2018).

Herraiz-Borreguero L., Lannuzel D., van der Merwe P., Treverrow A., Pedro J. B., Large flux of iron from the amery ice shelf marine ice to Prydz Bay, East Antarctica. J. Geophys. Res. Oceans 121, 6009–6020 (2016).

Cutter G. A., Trace elements in estuarine and coastal waters–U.S. studies from 1986–1990. Rev. Geophys. 29, 639–644 (1991).

Cape M. R., Straneo F., Beaird N., Bundy R. M., Charette M. A., Nutrient release to oceans from buoyancy-driven upwelling at Greenland tidewater glaciers. Nat. Geosci. 12, 34–39 (2019).

Kunde K., et al. , Iron distribution in the subtropical North Atlantic: The pivotal role of colloidal iron. Global Biogeochem. Cycles 33, 1532–1547 (2019).

Carter S. P., Fricker H. A., Siegfried M. R., Evidence of rapid subglacial water piracy under Whillans ice stream, west Antarctica. J. Glaciol. 59, 1147–1162 (2013).

Siegfried M. R., et al. , “Anatomy of a draining subglacial lake in West Antarctica” in AGU Fall Meeting (American Geophysical Union, San Francisco, CA, 2019), https://ui.adsabs.harvard.edu/abs/2019AGUFM.C12A..07S/abstract.

Anandakrishnan S., Blankenship D. D., Alley R. B., Stoffa P. L., Influence of subglacial geology on the position of a West Antarctic ice stream from seismic observations. Nature 394, 62–65 (1998).

Henriksen N., Higgins A. K., Kalsbeek F., Pulvertaft T. C. R., Greenland from Archaean to Quaternary Descriptive text to the 1995 Geological map of Greenland, 1:2 500 000. Geolog. Surv. Den. Greenl. 18, 1–126 (2009).

Pierrot D., Lewis E., Wallace D. W. R., “MS Excel program developed for CO2 system calculations” (Rep. ORNL/CDIAC-105, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, TN, 2006).

Carpenter J. H., The Chesapeake Bay Institute technique for the Winkler dissolved oxygen method. Limnol. Oceanogr. 10, 141–143 (1965).