Letter | Published:

Extensive dissolution of live pteropods in the Southern Ocean

Nature Geoscience volume 5, pages 881885 (2012) | Download Citation


The carbonate chemistry of the surface ocean is rapidly changing with ocean acidification, a result of human activities1. In the upper layers of the Southern Ocean, aragonite—a metastable form of calcium carbonate with rapid dissolution kinetics—may become undersaturated by 2050 (ref. 2). Aragonite undersaturation is likely to affect aragonite-shelled organisms, which can dominate surface water communities in polar regions3. Here we present analyses of specimens of the pteropod Limacina helicina antarctica that were extracted live from the Southern Ocean early in 2008. We sampled from the top 200 m of the water column, where aragonite saturation levels were around 1, as upwelled deep water is mixed with surface water containing anthropogenic CO2. Comparing the shell structure with samples from aragonite-supersaturated regions elsewhere under a scanning electron microscope, we found severe levels of shell dissolution in the undersaturated region alone. According to laboratory incubations of intact samples with a range of aragonite saturation levels, eight days of incubation in aragonite saturation levels of 0.94–1.12 produces equivalent levels of dissolution. As deep-water upwelling and CO2 absorption by surface waters is likely to increase as a result of human activities2,4, we conclude that upper ocean regions where aragonite-shelled organisms are affected by dissolution are likely to expand.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    , , , & Evidence for upwelling of corrosive ‘acidified’ water onto the continental shelf. Science 320, 1490–1492 (2008).

  2. 2.

    et al. Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437, 681–686 (2005).

  3. 3.

    et al. Pteropods in Southern Ocean ecosystems. Prog. Oceanogr. 78, 193–221 (2008).

  4. 4.

    et al. Saturation of the Southern Ocean CO2 sink due to recent climate change. Science 316, 1735–1738 (2007).

  5. 5.

    Shell growth rates of pteropod and heteropod molluscs and aragonite production in the open ocean: Implications for the marine carbonate system. J. Mar. Res. 48, 209–222 (1990).

  6. 6.

    & in The Fate of Fossil Fuel CO2 in the Oceans (eds Andersen, N. R. & Malahoff, A.) 213–241 (1977).

  7. 7.

    et al. The oceanic carbonate system—a reassessment of biogenic control. Science 226, 1074–1077 (1984).

  8. 8.

    et al. Impact of anthropogenic CO2 on the CaCO3 system in the oceans. Science 305, 362–366 (2004).

  9. 9.

    , , , & Water column dissolution of aragonite in the Pacific Ocean. Nature 312, 321–326 (1984).

  10. 10.

    et al. Winter-summer variations of calcite and aragonite saturation in the Northeast Pacific. Mar. Chem. 25, 227–241 (1988).

  11. 11.

    , , , & Aragonite undersaturation in the Arctic Ocean: Effects of ocean acidification and sea ice melt. Science 326, 1098–1100 (2009).

  12. 12.

    & Southern Ocean acidification: A tipping point at 450 ppm atmospheric CO2. Proc. Natl Acad. Sci. USA 105, 18860–18864 (2008).

  13. 13.

    , , , & Imminent ocean acidification in the Arctic projected with the NCAR global coupled carbon cycle-climate model. Biogeosciences 6, 515–533 (2009).

  14. 14.

    , , & Response of the Arctic pteropod Limacina helicina to projected future environmental conditions. PLoS ONE 5, e11362 (2010).

  15. 15.

    , , & Larvae of the pteropod Cavolinia inflexa exposed to aragonite undersaturation are viable but shell-less. Mar. Biol. 157, 2341–2345 (2010).

  16. 16.

    et al. Interannual pteropod variability in sediment traps deployed above and below the aragonite saturation horizon in the Sub-Antarctic Southern Ocean. Polar Biol. 34, 1739–1750 (2011).

  17. 17.

    , & High mixing rates in the abyssal Southern Ocean. Nature 415, 1011–1014 (2002).

  18. 18.

    , , , & Eddies enhance biological production in the Weddell-Scotia confluence of the Southern Ocean. Geophys. Res. Lett. 34, L14603 (2007).

  19. 19.

    , , & Variability of SeaWiFs chlorophyll-a in the southwest Atlantic sector of the Southern Ocean: Strong topographic effects and weak seasonality. Deep-Sea Res Pt. I 57, 604–620 (2010).

  20. 20.

    , , & Dynamic seasonal cycling of inorganic carbon downstream of South Georgia, Southern Ocean. Deep-Sea Res. Pt. II 59–60, 25–35 (2012).

  21. 21.

    , , & Population dynamics and biogeochemical significance of Limacina helicina antarctica in the Scotia Sea (Southern Ocean). Deep-Sea Res. Pt. II 59–60, 105–116 (2012).

  22. 22.

    , & Modeling the dissolution of settling CaCO3 in the ocean. Glob. Biogeochem. Cycles 16, 1027 (2002).

  23. 23.

    , , & Factors controlling the flux of organic carbon to the bathypelagic zone of the ocean. Glob. Biogeochem. Cycles 16, 1087 (2002).

  24. 24.

    , , & Ocean acidification at high latitudes: The bell weather. Oceanography 22, 160–171 (2009).

  25. 25.

    , , & Coulometric total carbon dioxide analysis for marine studies—automation and calibration. Mar. Chem. 21, 117–133 (1987).

  26. 26.

    An exact definition of total alkalinity and a procedure for the estimation of alkalinity and total inorganic carbon from titration data. Deep-Sea Res. 28, 609–623 (1981).

  27. 27.

    & co2sys - Program Developed for CO2 System Calculations Report ORNL/CDIAC-105 (Carbon Dioxide Information and Analysis Centre, Oak Ridge Natl. Lab., US Dep. of Energy, 1998).

  28. 28.

    , , & Measurement of the apparent dissociation constants of carbonic acid in seawater at atmospheric pressure. Limnol. Oceanogr. 18, 897–907 (1973).

  29. 29.

    & A comparison of the equilibrium constants for the dissociationof carbonic acid in seawater media. Deep-Sea Res. 34, 1733–1743 (1987).

  30. 30.

    et al. Description and quantification of pteropod shell dissolution: A sensitive bioindicator of ocean acidification. Global Change Biol. 18, 2378–2388 (2012).

Download references


This work was supported by the FAASIS (Fellowships in Antarctic Air-Sea-Ice Science), a Marie Curie Early Stage Training Network awarded to N.B. G.A.T., S.F. and P.W. carried out this work as part of the Ecosystems core-science programme at the British Antarctic Survey. G.A.T., P.W. and D.B. received further support during the analysis and synthesis stages from the pelagic consortium of the UK Ocean Acidification programme, funded by NERC, Defra and DECC (grant no. NE/H017267/1). D. McCorkle and A. Cohen of Woods Hole Oceanographic Institution helped develop a shell preparation method and commented on previous drafts of the manuscript. Image analysis was carried out at the University of East Anglia with the assistance of R. Montagna. Sampling operations were supported by the officers and crew of the RRS James Clark Ross with net-sampling equipment support from P. Enderlein of the British Antarctic Survey. P. Bucktrout assisted with graphical presentations.

Author information


  1. British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK

    • N. Bednaršek
    • , G. A. Tarling
    • , S. Fielding
    • , H. J. Venables
    • , P. Ward
    •  & E. J. Murphy
  2. School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK

    • N. Bednaršek
    • , D. C. E. Bakker
    •  & B. Lézé
  3. University of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia

    • N. Bednaršek
  4. Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB Den Burg, Texel, The Netherlands

    • E. M. Jones
  5. Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA

    • A. Kuzirian
  6. NOAA, Pacific Marine Environmental Laboratory, Seattle, Washington 98115, USA

    • R. A. Feely


  1. Search for N. Bednaršek in:

  2. Search for G. A. Tarling in:

  3. Search for D. C. E. Bakker in:

  4. Search for S. Fielding in:

  5. Search for E. M. Jones in:

  6. Search for H. J. Venables in:

  7. Search for P. Ward in:

  8. Search for A. Kuzirian in:

  9. Search for B. Lézé in:

  10. Search for R. A. Feely in:

  11. Search for E. J. Murphy in:


G.A.T. and D.C.E.B. conceived the project; N.B. carried out the fieldwork, with the assistance of G.A.T., S.F. and P.W.; E.M.J. and H.J.V. provided supporting environmental data; A.K. helped develop a method of shell preparation for SEM analysis; B.L. developed an image analysis method; G.A.T., N.B. and D.C.E.B. co-wrote the manuscript, with theoretical overviews provided by R.A.F. and all remaining authors commenting.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to G. A. Tarling.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Information


  1. 1.

    Supplementary Movie

    Supplementary Movie

About this article

Publication history






Further reading