Letter | Published:

Enhanced Southern Ocean marine productivity due to fertilization by giant icebergs

Nature Geoscience volume 9, pages 219221 (2016) | Download Citation

  • A Corrigendum to this article was published on 01 September 2016

This article has been updated


Primary productivity is enhanced within a few kilometres of icebergs in the Weddell Sea1,2 owing to the input of terrigeneous nutrients and trace elements during iceberg melting. However, the influence of giant icebergs, over 18 km in length, on marine primary production in the Southern Ocean is less well studied1,3. Here we present an analysis of 175 satellite images of open ocean colour before and after the passage of 17 giant icebergs between 2003 and 2013. We detect substantially enhanced chlorophyll levels, typically over a radius of at least 4–10 times the iceberg’s length, that can persist for more than a month following passage of a giant iceberg. This area of influence is more than an order of magnitude larger than that found for sub-kilometre scale icebergs2 or in ship-based surveys of giant icebergs1. Assuming that carbon export increases by a factor of 5–10 over the area of influence, we estimate that up to a fifth of the Southern Ocean’s downward carbon flux originates with giant iceberg fertilization. We suggest that, if giant iceberg calving increases this century as expected4, this negative feedback on the carbon cycle may become more important.

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Change history

  • 16 August 2016

    In the version of this Letter originally published, it was incorrectly stated in Figure 1 that Chlorophyll-α concentrations were recorded on 12 January 2013, when the date should have been 1 December 2013. This has been corrected in the online versions of the paper.


  1. 1.

    et al. Free-drifting icebergs: hot spots of chemical and biological enrichment in the Weddell Sea. Science 317, 478–482 (2007).

  2. 2.

    & Impact of drifting icebergs on surface phytoplankton biomass in the Southern Ocean: ocean colour remote sensing and in situ iceberg tracking. Deep-Sea Res. I 56, 1727–1741 (2009).

  3. 3.

    , , & Cooling, dilution and mixing of ocean water by free-drifting icebergs in the Weddell Sea. Deep-Sea Res. II 58, 1336–1345 (2011).

  4. 4.

    , & Marine ice sheet collapse potentially under way for the Thwaites Glacier Basin, West Antarctica. Science 344, 735–738 (2014).

  5. 5.

    et al. in Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) 465–570 (IPCC, Cambridge Univ. Press, 2013).

  6. 6.

    , & Iron deficiency limits phytoplankton growth in Antarctic waters. Glob. Biogeochem. Cycles 4, 5–12 (1990).

  7. 7.

    et al. Atmospheric iron deposition: global distribution, variability and human perturbations. Ann. Rev. Mar. Sci. 1, 245–278 (2009).

  8. 8.

    et al. A biogeochemical study of the island mass effect in the context of the iron hypothesis: Kerguelen Islands, Southern Ocean. Deep-Sea Res. I 48, 163–187 (2001).

  9. 9.

    et al. Spatial distribution of the iron supply to phytoplankton in the Southern Ocean: a model study. Biogeosciences 6, 2861–2878 (2009).

  10. 10.

    et al. Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans. Nature Commun. 5, 3929 (2014).

  11. 11.

    , & The role of iron sources and transport for Southern Ocean productivity. Deep-Sea Res. I 87, 82–94 (2014).

  12. 12.

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

  13. 13.

    , , & Bioavailable iron in the Southern Ocean: the significance of the iceberg conveyor belt. Geochem. Trans. 9 (2008).

  14. 14.

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

  15. 15.

    , & The contribution of giant icebergs to the Southern Ocean freshwater flux. J. Geophys. Res. Oceans 111, C03004 (2006).

  16. 16.

    et al. Iron study during a time series in the western Weddell pack ice. Mar. Chem. 108, 85–95 (2008).

  17. 17.

    , & Basal melting of A-38B: a physical model constrained by satellite observations. Remote Sens. Env. 111, 195–203 (2007).

  18. 18.

    et al. Carbon export associated with free-drifting icebergs in the Southern Ocean. Deep-Sea Res. II 58, 1485–1496 (2011).

  19. 19.

    et al. Input, composition and potential impact of terrigenous material from free-drifting icebergs. Deep-Sea Res. II 58, 1376–1383 (2011).

  20. 20.

    et al. Icebergs as unique Lagrangian ecosystems in polar seas. Ann. Rev. Mar. Sci. 5, 269–287 (2013).

  21. 21.

    Tectonic Map of Antarctica (Antarctic Map Folio Series, Folio 12-Geology, Amer. Geogr. Soc., 1970).

  22. 22.

    et al. Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise. Geophys. Res. Lett. 38, L05503 (2011).

  23. 23.

    , & Volume loss from Antarctic ice shelves is accelerating. Science 348, 327–331 (2015).

  24. 24.

    , & Inputs of glacially derived dissolved and colloidal iron to the coastal ocean and implications for primary productivity. Glob. Biogeochem. Cycles 22, GB3013 (2008).

  25. 25.

    , , & B31—a giant iceberg in the Southern Ocean. Ocean Challenge 20, 32–34 (2014).

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Much of this work followed from the MSc dissertation of L.P.A.M.D. We also acknowledge support for part of the work from the Natural Environment Research Council Urgency Grant NE/L010054/1, ‘Tracking and prediction of the giant Pine Island iceberg’, and SAR images from the German Aerospace Center Projects OCE2116 and 2184 and the European Space Agency project 16456. We wish to thank the Canadian Space Agency for providing the data from the latter ESA project. We also wish to thank E. Victor, who helped L.P.A.M.D. with some of the statistics, and J. Thompson, whose MSc research brought the comparisons shown in Fig. 3 to our attention.

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  1. Department of Geography, University of Sheffield, Sheffield S10 2TN, UK

    • Luis P. A. M. Duprat
    • , Grant R. Bigg
    •  & David J. Wilton


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G.R.B. and L.P.A.M.D. conceived the project; L.P.A.M.D. carried out much of the analysis and assisted with writing; G.R.B. contributed to the analysis and was the principal writer of the final manuscript. D.J.W. carried out some of the tracking work shown in Fig. 3, and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Grant R. Bigg.

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