Letter | Published:

Coral and mollusc resistance to ocean acidification adversely affected by warming

Nature Climate Change volume 1, pages 308312 (2011) | Download Citation


Increasing atmospheric carbon dioxide (CO2) concentrations are expectedto decrease surface ocean pH by 0.3–0.5 units by 2100 (refs 1, 2), lowering the carbonate ion concentration of surfacewaters. This rapid acidification is predicted to dramatically decrease calcification in many marine organisms3,4. Reduced skeletal growth under increased CO2 levels has already been shown for corals, molluscs and many other marine organisms4,5,6,7,8,9. The impact of acidification on the ability of individual species to calcify has remained elusive, however, as measuring net calcification fails to disentangle the relative contributions of gross calcification and dissolution rates on growth. Here, we show that corals and molluscs transplanted along gradients of carbonate saturation state at Mediterranean CO2 vents are able to calcify and grow at even faster than normal rates when exposed to the high CO2 levels projected for the next 300 years. Calcifiers remain at risk, however, owing to the dissolution of exposed shells and skeletons that occurs as pH levels fall. Our results show that tissues and external organic layers play a major role in protecting shells and skeletons from corrosive sea water, limiting dissolution and allowing organisms to calcify10,11. Our combined field and laboratory results demonstrate that the adverse effects of global warming are exacerbated when high temperatures coincide with acidification.

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We thank all collaborators from Stazione Zoologica ‘A. Dohrn’ for their help during fieldwork, D. Allemand and C. Ferrier-Pagès for helpful discussions, and J-F. Comanducci, F. Oberhänsli and J-L. Teyssié for their help during radiotracer experiments. Comments by P. Mumby and J. Ries improved this manuscript. This work was funded by the Prince Albert II of Monaco Foundation, the International Atomic Energy Agency (IAEA-NAML, Monaco, which is grateful to the Government of the Principality of Monaco for the support provided to its Environment Laboratories), Save our Seas Foundation, an EU MARES studentship and the EU ‘Mediterranean Sea Acidification under a changing climate’ project (MedSeA; grant agreement 265103). The work contributes to the European Project on Ocean Acidification (EPOCA; grant agreement 211384).

Author information

Author notes

    • F. Houlbrèque

    Present addresses: Centre IRD, 98848, Noumea, Nouvelle-Caledonie, France (F.H.); School of the Environment, Faculty of Science, University of Technology, NSW 2007 Sydney, Australia (R.J.)


  1. International Atomic Energy Agency—Marine Environment Laboratories, 4 Quai Antoine 1er, 98000 Monaco, Principality of Monaco

    • R. Rodolfo-Metalpa
    • , F. Houlbrèque
    • , F. Boisson
    •  & R. Jeffree
  2. Marine Institute, Marine Biology and Ecology Research Centre, University of Plymouth, Plymouth PL4 8AA, UK

    • R. Rodolfo-Metalpa
    • , C. Baggini
    • , A. Foggo
    •  & J. M. Hall-Spencer
  3. Centre Scientifique de Monaco, Avenue Saint Martin, 98000 Monaco, Principality of Monaco

    • É. Tambutté
  4. Stazione Zoologica ‘A. Dohrn’, Functional and Evolutionary Ecology Laboratory, Punta S. Pietro, 80077 Ischia (Naples), Italy

    • F. P. Patti
  5. The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel

    • M. Fine
  6. Interuniversity Institute for Marine Science, Eilat 88103, Israel

    • M. Fine
  7. INSU-CNRS, Laboratoire d’Océanographie de Villefranche, B.P. 28, 06234 Villefranche-sur-mer Cedex, France

    • J-P. Gattuso
  8. UPMC University of Paris 06, Observatoire Océanologique de Villefranche, 06230 Villefranche-sur-mer, France

    • J-P. Gattuso


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R.R-M. and F.B. designed the study. Most experiments were performed by R.R-M., who wrote the paper in collaboration with F.H., J.M.H-S., M.F. and J-P.G. Coral radiotracer incorporation was performed by F.H. Scanning electron microscopy was performed by E.T. on corals and C.B. on mussels. A.F. performed the statistical analysis. All authors read and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to R. Rodolfo-Metalpa.

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