Abstract
The discharge of nutrient-rich meltwater from the Greenland Ice Sheet has emerged as a potentially important contributor to regional marine primary production and nutrient cycling. While significant, this direct nutrient input by the ice sheet may be secondary to the upwelling of deep-ocean-sourced nutrients driven by the release of meltwater at depth in glacial fjords. Here, we present a comprehensive suite of micro- and macronutrient observations collected in Sermilik Fjord at the margin of Helheim, one of Greenland’s largest glaciers, and quantitatively decompose glacial and ocean contributions to fjord dissolved nutrient inventories. We show that the substantial enrichment in nitrate, phosphate and silicate observed in the upper 250 m of the glacial fjord is the result of upwelling of warm subtropical waters present at depth throughout the fjord. These nutrient-enriched fjord waters are subsequently exported subsurface to the continental shelf. The upwelled nutrient transport within Sermilik rivals exports by the largest Arctic rivers and the ice sheet as a whole, suggesting that glacier-induced pumping of deep nutrients may constitute a major source of macronutrients to the surrounding coastal ocean. The importance of this mechanism is likely to grow given projected increases in surface melt of the ice sheet.
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Data availability
Continuous hydrographic (CTD) profiles are available from the National Oceanographic Data Center (http://accession.nodc.noaa.gov/0171277), while discrete nutrient measurements and CTD bottle data (https://doi.org/10.1594/PANGAEA.887304), as well as discrete iron data (https://doi.org/10.1594/PANGAEA.887324), are available from the PANGEA information system77,78. Ocean current data for Sermilik Fjord are publicly available from Data.gov(NODC accession number 0126772 and NCEI accession number 0127325). Downscaled RACMO2.3.2 data were provided by M. van den Broeke and B. Noël and are available from them upon request. Hydrographic data for the West Greenland continental shelf (Supplementary Table 2 and Supplementary Fig. 12) are available from K. Azetsu-Scott upon request. Other data supporting the findings of this study are available as described in the Methods, and otherwise from the corresponding author upon request.
References
Wadham, J. L. et al. The potential role of the Antarctic Ice Sheet in global biogeochemical cycles. Earth Environ. Sci. Trans. R. Soc. Edinb. 104, 55–67 (2013).
O’Neel, S. et al. Icefield-to-ocean linkages across the northern Pacific coastal temperate rainforest ecosystem. BioScience 65, 499–512 (2015).
Böning, C. W., Behrens, E., Biastoch, A., Getzlaff, K. & Bamber, J. L. Emerging impact of Greenland meltwater on deepwater formation in the North Atlantic Ocean. Nat. Geosci. 9, 523–527 (2016).
Hodson, A. et al. Glacial ecosystems. Ecol. Monogr. 78, 41–67 (2008).
Wadham, J. L. et al. Biogeochemical weathering under ice: size matters. Global Biogeochem. Cycles 24, GB3025 (2010).
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).
Hawkings, J. et al. The Greenland Ice Sheet as a hot spot of phosphorus weathering and export in the Arctic. Global Biogeochem. Cycles 30, 191–210 (2016).
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).
Hawkings, J. R. et al. Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans. Nat. Commun. 5, 3929 (2014).
Hopwood, M. J. et al. Seasonal changes in Fe along a glaciated Greenlandic fjord. Front. Earth Sci. 4, 15 (2016).
Luo, H. et al. Oceanic transport of surface meltwater from the southern Greenland ice sheet. Nat. Geosci. 9, 528–532 (2016).
Arrigo, K. R. et al. Melting glaciers stimulate large summer phytoplankton blooms in southwest Greenland waters. Geophys. Res. Lett. 44, 6278–6285 (2017).
Oliver, H. et al. Exploring the potential impact of Greenland meltwater on stratification, photosynthetically active radiation, and primary production in the Labrador Sea. J. Geophys. Res. Oceans 123, 2570–2591 (2018).
Meire, L. et al. Marine-terminating glaciers sustain high productivity in Greenland fjords. Global Change Biol. 23, 5344–5357 (2017).
Kanna, N. et al. Upwelling of macronutrients and dissolved inorganic carbon by a subglacial freshwater driven plume in Bowdoin Fjord, Northwestern Greenland. J. Geophys. Res. Biogeosci. 123, 1666–1682 (2018).
Enderlin, E. M. et al. An improved mass budget for the Greenland Ice Sheet. Geophys. Res. Lett. 41, 866–872 (2014).
Straneo, F. & Cenedese, C. The dynamics of Greenland’s glacial fjords and their role in climate. Annu. Rev. Mar. Sci. 7, 89–112 (2015).
van den Broeke, M. et al. Partitioning recent Greenland mass loss. Science 326, 984–986 (2009).
Rignot, E. & Mouginot, J. Ice flow in Greenland for the International Polar Year 2008–2009. Geophys. Res. Lett. 39, L11501 (2012).
Chu, V. W. Greenland ice sheet hydrology: a review. Prog. Phys. Geogr. 38, 19–54 (2014).
Moon, T. et al. Subsurface iceberg melt key to Greenland fjord freshwater budget. Nat. Geosci. 11, 49–54 (2018).
Jenkins, A. Convection-driven melting near the grounding lines of ice shelves and tidewater glaciers. J. Phys. Oceanogr. 41, 2279–2294 (2011).
Sciascia, R., Straneo, F., Cenedese, C. & Heimbach, P. Seasonal variability of submarine melt rate and circulation in an East Greenland fjord. J. Geophys. Res. Oceans 118, 2492–2506 (2013).
Bendtsen, J., Mortensen, J., Lennert, K. & Rysgaard, S. Heat sources for glacial ice melt in a west Greenland tidewater outlet glacier fjord: the role of subglacial freshwater discharge. Geophys. Res. Lett. 42, 4089–4095 (2015).
Beaird, N., Straneo, F. & Jenkins, W. Spreading of Greenland meltwaters in the ocean revealed by noble gases. Geophys. Res. Lett. 42, 7705–7713 (2015).
Straneo, F. et al. Impact of fjord dynamics and glacial runoff on the circulation near Helheim Glacier. Nat. Geosci. 4, 322–327 (2011).
Mortensen, J. et al. On the seasonal freshwater stratification in the proximity of fast-flowing tidewater outlet glaciers in a sub-Arctic sill fjord. J. Geophys. Res. Oceans 118, 1382–1395 (2013).
Beaird, N., Straneo, F. & Jenkins, W. Characteristics of meltwater export from Jakobshavn Isbræ and Ilulissat Icefjord. Ann. Glaciol. 58, 107–117 (2017).
Bamber, J., van den Broeke, M., Ettema, J., Lenaerts, J. & Rignot, E. Recent large increases in freshwater fluxes from Greenland into the North Atlantic. Geophys. Res. Lett. 39, L19501 (2012).
Harden, B. E., Straneo, F. & Sutherland, D. A. Moored observations of synoptic and seasonal variability in the East Greenland Coastal Current. J. Geophys. Res. Oceans 119, 8838–8857 (2014).
Sutherland, D. A., Straneo, F. & Pickart, R. S. Characteristics and dynamics of two major Greenland glacial fjords. J. Geophys. Res. Oceans 119, 3767–3791 (2014).
Beaird, N. L., Straneo, F. & Jenkins, W. Export of strongly diluted Greenland meltwater from a major glacial fjord. Geophys. Res. Lett. 45, 4163–4170 (2018).
Straneo, F. et al. Rapid circulation of warm subtropical waters in a major glacial fjord in East Greenland. Nat. Geosci. 3, 182–186 (2010).
Straneo, F. et al. Characteristics of ocean waters reaching Greenland’s glaciers. Ann. Glaciol. 53, 202–210 (2012).
Jackson, R. H. & Straneo, F. Heat, salt, and freshwater budgets for a glacial fjord in Greenland. J. Phys. Oceanogr. 46, 2735–2768 (2016).
Lydersen, C. et al. The importance of tidewater glaciers for marine mammals and seabirds in Svalbard, Norway. J. Mar. Syst. 129, 452–471 (2014).
Azetsu-Scott, K. & Syvitski, J. P. M. Influence of melting icebergs on distribution, characteristics and transport of marine particles in an East Greenland fjord. J. Geophys. Res. Solid Earth 104, 5321–5328 (1999).
Hawkings, J. R. et al. Ice sheets as a missing source of silica to the polar oceans. Nat. Commun. 8, 14198 (2017).
Gade, H. G. Melting of ice in sea water: a primitive model with application to the Antarctic Ice Shelf and icebergs. J. Phys. Oceanogr. 9, 189–198 (1979).
Jenkins, A. The impact of melting ice on ocean waters. J. Phys. Oceanogr. 29, 2370–2381 (1999).
Bhatia, M. P. Hydrological and Biogeochemical Cycling along the Greenland Ice Sheet Margin. PhD thesis, Massachusetts Institute of Technology (2012).
Wadham, J. L. et al. Sources, cycling and export of nitrogen on the Greenland Ice Sheet. Biogeosciences 13, 6339–6352 (2016).
Tomczak, M. & Large, D. G. B. Optimum multiparameter analysis of mixing in the thermocline of the eastern Indian Ocean. J. Geophys. Res. Oceans 94, 16141–16149 (1989).
Hartley, C. H. & Dunbar, M. J. On the hydrographic mechanism of the so-called brown zones associated with tidal glaciers. J. Mar. Res. 1, 305–311 (1938).
Dunbar, M. J. Glaciers and nutrients in Arctic fiords. Science 182, 398–398 (1973).
Horne, E. P. W. Ice-induced vertical circulation in an Arctic fiord. J. Geophys. Res. 90, 1078–1086 (1985).
Jackson, R. H., Straneo, F. & Sutherland, D. A. Externally forced fluctuations in ocean temperature at Greenland glaciers in non-summer months. Nat. Geosci. 7, 503–508 (2014).
Millan, R. et al. Vulnerability of Southeast Greenland glaciers to warm Atlantic water from Operation IceBridge and Ocean Melting Greenland data. Geophys. Res. Lett. 45, 2688–2696 (2018).
Holmes, R. M. et al. Seasonal and annual fluxes of nutrients and organic matter from large rivers to the Arctic Ocean and surrounding seas. Estuaries Coast. 35, 369–382 (2011).
Emmerton, C. A., Lesack, L. F. W. & Vincent, W. F. Nutrient and organic matter patterns across the Mackenzie River, estuary and shelf during the seasonal recession of sea-ice. J. Mar. Syst. 74, 741–755 (2008).
Meire, L. et al. High export of dissolved silica from the Greenland Ice Sheet. Geophys. Res. Lett. 43, 9173–9182 (2016).
Hopwood, M. J., Bacon, S., Arendt, K., Connelly, D. P. & Statham, P. J. Glacial meltwater from Greenland is not likely to be an important source of Fe to the North Atlantic. Biogeochemistry 124, 1–11 (2015).
Boyle, E. A., Edmond, J. M. & Sholkovitz, E. R. The mechanism of iron removal in estuaries. Geochim. Cosmochim. Acta 41, 1313–1324 (1977).
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).
Achterberg, E. P. et al. Iron biogeochemistry in the high latitude North Atlantic Ocean. Sci. Rep. 8, 1283 (2018).
Straneo, F. & Heimbach, P. North Atlantic warming and the retreat of Greenland’s outlet glaciers. Nature 504, 36–43 (2013).
Fouest, V. L., Babin, M. & Tremblay, J. É. The fate of riverine nutrients on Arctic shelves. Biogeosciences 10, 3661–3677 (2013).
Guo, L., Zhang, J.-Z. & Guéguen, C. Speciation and fluxes of nutrients (N, P, Si) from the upper Yukon River. Global Biogeochem. Cycles 18, GB1038 (2004).
Macdonald, R. W., McLaughlin, F. A. & Wong, C. S. The storage of reactive silicate samples by freezing. Limnol. Oceanogr. 31, 1139–1142 (2003).
Rice, E. W., Baird, R. B., Eaton, A. D. & Clesceri, L. S. (eds) Standard Methods for the Examination of Water and Wastewater 22nd edn (American Public Health Association, American Water Works Association (AWWA), Water Environment Federation, Washington DC, 2012).
Grasshoff, K., Kremling, K. & Ehrhardt, M. (eds) Methods of Seawater Analysis 3rd edn (Wiley-VCH Verlag, Weinheim, 2007).
Cutter, G. A. Intercalibration in chemical oceanography—getting the right number. Limnol. Oceanogr. Methods 11, 418–424 (2013).
Martin, J. H. et al. Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean. Nature 371, 123–129 (1994).
Abualhaija, M. M. & van den Berg, C. M. G. Chemical speciation of iron in seawater using catalytic cathodic stripping voltammetry with ligand competition against salicylaldoxime. Mar. Chem. 164, 60–74 (2014).
Hinrichsen, H. H. & Tomczak, M. Optimum multiparameter analysis of the water mass structure in the western North Atlantic Ocean. J. Geophys. Res. Oceans 98, 10155–10169 (1993).
Karstensen, J. & Tomczak, M. Age determination of mixed water masses using CFC and oxygen data. J. Geophys. Res. Oceans 103, 18599–18609 (1998).
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).
Carroll, D. et al. Modeling turbulent subglacial meltwater plumes: implications for fjord-scale buoyancy-driven circulation. J. Phys. Oceanogr. 45, 2169–2185 (2015).
Noël, B. et al. A daily, 1 km resolution data set of downscaled greenland ice sheet surface mass balance (1958–2015). Cryosphere 10, 2361–2377 (2016).
Mernild, S. H. et al. Freshwater flux to Sermilik Fjord, SE Greenland. Cryosphere 4, 453–465 (2010).
Lewis, S. Hydrologic Sub-basins of Greenland Version 1 (National Snow and Ice Data Center, Boulder, 2009).
Lewis, S. M. & Smith, L. C. Hydrologic drainage of the Greenland Ice Sheet. Hydrol. Process. 23, 2004–2011 (2009).
Azetsu-Scott, K., Petrie, B., Yeats, P. & Lee, C. Composition and fluxes of freshwater through Davis Strait using multiple chemical tracers. J. Geophys. Res. Oceans 117, C12011 (2012).
Vernon, C. L. et al. Surface mass balance model intercomparison for the Greenland Ice Sheet. Cryosphere 7, 599–614 (2013).
Sutterley, T. C. et al. Evaluation of reconstructions of snow/ice melt in Greenland by regional atmospheric climate models using laser altimetry data. Geophys. Res. Lett. 45, 8324–8333 (2018).
Mernild, S. H. et al. Freshwater flux and spatiotemporal simulated runoff variability into Ilulissat Icefjord, West Greenland, linked to salinity and temperature observations near tidewater glacier margins obtained using instrumented ringed seals. J. Phys. Oceanogr. 45, 1426–1445 (2015).
Cape, M. R., Straneo, F. & Charette, M. A. Hydrographic sensor and bottle data collected during an August 2015 cruise to Sermilik Fjord, East Greenland. PANGAEA https://doi.org/10.1594/PANGAEA.887304(2018).
Cape, M. R., Bundy, R. M. & Straneo, F. Surface total dissolvable iron data collected during an August 2015 cruise to Sermilik Fjord, East Greenland. PANGAEA https://doi.org/10.1594/PANGAEA.887324(2018).
Acknowledgements
This work was supported by: an internal grant from the Woods Hole Oceanographic Institution (WHOI) Ocean and Climate Change Institute (to M.R.C., F.S. and M.A.C.), grants from the National Science Foundation to M.A.C. (OCE-1458305), N.B. (OCE-1536856) and F.S. (OCE-1657601), and Woods Hole Oceanographic Institution Postdoctoral Fellowships to M.R.C. and R.M.B. We are grateful to J. Hawkings for sharing Leverett Glacier nutrient data, to K. Azetsu-Scott and B. Curry for sharing the Davis Strait and West Greenland continental shelf hydrographic data, to P. Henderson and the WHOI Nutrient Analytical Facility for assistance with macronutrient sample collection and analysis, to R. Jackson for helpful conversations concerning data analysis, to A. Ramsey for logistical support, to S. Laney for loan of and technical assistance with oceanographic instrumentation, to M. Swartz for CTD assembly and testing, and to the captain and crew of the RV Adolf Jensen for support in the field.
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M.R.C. and F.S. conceived the study with input from M.A.C. M.R.C., F.S. and N.B. collected data and samples in the field. M.A.C. and R.M.B analysed water samples. M.R.C., N.B. and R.M.B. analysed the resulting data. M.R.C. wrote the paper, with assistance from all co-authors.
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Cape, M.R., Straneo, F., Beaird, N. et al. Nutrient release to oceans from buoyancy-driven upwelling at Greenland tidewater glaciers. Nature Geosci 12, 34–39 (2019). https://doi.org/10.1038/s41561-018-0268-4
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DOI: https://doi.org/10.1038/s41561-018-0268-4
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