Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Extensive dissolution of live pteropods in the Southern Ocean


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.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Scotia Sea showing sampling station positions and frontal positions at time of sampling.
Figure 2: Vertical profiles of ΩA across the Scotia Sea (upper) and corresponding dissolution levels in live juvenile L. helicina antarctica (lower).
Figure 3
Figure 4: SEM images of juvenile L. helicina antarctica (from which the periostracum has been removed) showing different levels of dissolution.
Figure 5: Average (s.d.) proportion of different dissolution levels in live juvenile L. helicina antarctica from the natural environment and ship-board incubations.

Similar content being viewed by others


  1. Feely, R. A., Sabine, C. L., Hernandez-Ayon, J. M., Ianson, D. & Hales, B. Evidence for upwelling of corrosive ‘acidified’ water onto the continental shelf. Science 320, 1490–1492 (2008).

    Article  Google Scholar 

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

    Article  Google Scholar 

  3. Hunt, B. P. V. et al. Pteropods in Southern Ocean ecosystems. Prog. Oceanogr. 78, 193–221 (2008).

    Article  Google Scholar 

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

    Article  Google Scholar 

  5. Fabry, V. J. 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).

    Article  Google Scholar 

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

    Book  Google Scholar 

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

    Article  Google Scholar 

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

    Article  Google Scholar 

  9. Byrne, R. H., Acker, J. G., Betzer, P. R., Feely, R. A. & Cates, M. H. Water column dissolution of aragonite in the Pacific Ocean. Nature 312, 321–326 (1984).

    Article  Google Scholar 

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

    Article  Google Scholar 

  11. Yamamoto-Kawai, M., McLaughlin, F. A., Carmack, E. C., Nishino, S. & Shimada, K. Aragonite undersaturation in the Arctic Ocean: Effects of ocean acidification and sea ice melt. Science 326, 1098–1100 (2009).

    Article  Google Scholar 

  12. McNeil, B. I. & Matear, R. J. Southern Ocean acidification: A tipping point at 450 ppm atmospheric CO2 . Proc. Natl Acad. Sci. USA 105, 18860–18864 (2008).

    Article  Google Scholar 

  13. Steinacher, M., Joos, F., Frolicher, T. L., Plattner, G. K. & Doney, S. C. Imminent ocean acidification in the Arctic projected with the NCAR global coupled carbon cycle-climate model. Biogeosciences 6, 515–533 (2009).

    Article  Google Scholar 

  14. Comeau, S., Jeffree, R., Teyssie, J. L. & Gattuso, J. P. Response of the Arctic pteropod Limacina helicina to projected future environmental conditions. PLoS ONE 5, e11362 (2010).

    Article  Google Scholar 

  15. Comeau, S., Gorsky, G., Alliouane, S. & Gattuso, J. P. Larvae of the pteropod Cavolinia inflexa exposed to aragonite undersaturation are viable but shell-less. Mar. Biol. 157, 2341–2345 (2010).

    Article  Google Scholar 

  16. Roberts, D. 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).

    Article  Google Scholar 

  17. Heywood, K. J., Garabato, A. C. N. & Stevens, D. P. High mixing rates in the abyssal Southern Ocean. Nature 415, 1011–1014 (2002).

    Article  Google Scholar 

  18. Kahru, M., Mitchell, B. G., Gille, S. T., Hewes, C. D. & Holm-Hansen, O. Eddies enhance biological production in the Weddell-Scotia confluence of the Southern Ocean. Geophys. Res. Lett. 34, L14603 (2007).

    Article  Google Scholar 

  19. Park, J., Ohb, I-S., Kim, H-C. & Yoo, S. 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).

    Article  Google Scholar 

  20. Jones, E., Bakker, D., Venables, H. & Watson, A. Dynamic seasonal cycling of inorganic carbon downstream of South Georgia, Southern Ocean. Deep-Sea Res. Pt. II 59–60, 25–35 (2012).

    Article  Google Scholar 

  21. Bednarsek, N., Tarling, G., Fielding, S. & Bakker, D. 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).

    Article  Google Scholar 

  22. Jansen, H., Zeebe, R.E. & Wolf-Gladrow, D.A. Modeling the dissolution of settling CaCO3 in the ocean. Glob. Biogeochem. Cycles 16, 1027 (2002).

    Article  Google Scholar 

  23. Francois, R., Honjo, S., Krishfield, R. & Manganini, S. Factors controlling the flux of organic carbon to the bathypelagic zone of the ocean. Glob. Biogeochem. Cycles 16, 1087 (2002).

    Article  Google Scholar 

  24. Fabry, V. J., McClintock, J. B., Mathis, J. T. & Grebmeier, J. M. Ocean acidification at high latitudes: The bell weather. Oceanography 22, 160–171 (2009).

    Article  Google Scholar 

  25. Johnson, K. M., Sieburth, J. M., Williams, P. J. L. & Brandstrom, L. Coulometric total carbon dioxide analysis for marine studies—automation and calibration. Mar. Chem. 21, 117–133 (1987).

    Article  Google Scholar 

  26. Dickson, A. G. 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).

    Article  Google Scholar 

  27. Lewis, E. & Wallace, D. W. R. co2sys - Program Developed for CO 2 System Calculations Report ORNL/CDIAC-105 (Carbon Dioxide Information and Analysis Centre, Oak Ridge Natl. Lab., US Dep. of Energy, 1998).

  28. Mehrbach, C., Culberson, C. H., Hawley, J. E. & Pytkowicz, R. M. Measurement of the apparent dissociation constants of carbonic acid in seawater at atmospheric pressure. Limnol. Oceanogr. 18, 897–907 (1973).

    Article  Google Scholar 

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

    Article  Google Scholar 

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

    Article  Google Scholar 

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

Authors and Affiliations



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.

Corresponding author

Correspondence to G. A. Tarling.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 1918 kb)

Supplementary Movie

Supplementary Movie (MOV 19156 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Bednaršek, N., Tarling, G., Bakker, D. et al. Extensive dissolution of live pteropods in the Southern Ocean. Nature Geosci 5, 881–885 (2012).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing