Articles | Volume 11, issue 24
https://doi.org/10.5194/bg-11-7363-2014
https://doi.org/10.5194/bg-11-7363-2014
Research article
 | 
20 Dec 2014
Research article |  | 20 Dec 2014

Limpets counteract ocean acidification induced shell corrosion by thickening of aragonitic shell layers

G. Langer, G. Nehrke, C. Baggini, R. Rodolfo-Metalpa, J. M. Hall-Spencer, and J. Bijma

Abstract. Specimens of the patellogastropod limpet Patella caerulea were collected within (pHlow-shells) and outside (pHn-shells) a CO2 vent site at Ischia, Italy. Four pHlow-shells and four pHn-shells were sectioned transversally and scanned for polymorph distribution by means of confocal Raman microscopy. The pHlow-shells displayed a twofold increase in aragonite area fraction and size-normalised aragonite area. Size-normalised calcite area was halved in pHlow-shells. Taken together with the increased apical and the decreased flank size-normalised thickness of the pHlow-shells, these data led us to conclude that low-pH-exposed P. caerulea specimens counteract shell dissolution by enhanced shell production. This is different from normal elongation growth and proceeds through addition of aragonitic parts only, while the production of calcitic parts is confined to elongation growth. Therefore, aragonite cannot be regarded as a disadvantageous polymorph per se under ocean acidification conditions.

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Short summary
Specimens of the patellogastropod limpet Patella caerulea were collected within and outside a CO2 vent site at Ischia, Italy. The distribution of different crystal structures across shell sections was analysed. Patella caerulea counteracts shell dissolution in corrosive waters by enhanced production of aragonitic parts of the shell. We conclude that it is not possible to predict the dissolution behaviour of a composite biomineral on the basis of the properties of its constituent mineral.
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