Detrimental effects of ocean acidification on the economically important Mediterranean red coral (Corallium rubrum)

The mean predicted decrease of 0.3-0.4 pH units in the global surface ocean by the end of the century has prompted urgent research to assess the potential effects of ocean acidification on the marine environment, with strong emphasis on calcifying organisms. Among them, the Mediterranean red coral (Corallium rubrum) is expected to be particularly susceptible to acidification effects, due to the elevated solubility of its Mg-calcite skeleton. This, together with the large overexploitation of this species, depicts a bleak future for this organism over the next decades. In this study, we evaluated the effects of low pH on the species from aquaria experiments. Several colonies of C. rubrum were long-term maintained for 314 days in aquaria at two different pH levels (8.10 and 7.81, pHT). Calcification rate, spicule morphology, major biochemical constituents (protein, carbohydrates and lipids) and fatty acids composition were measured periodically. Exposure to lower pH conditions caused a significant decrease in the skeletal growth rate in comparison with the control treatment. Similarly, the spicule morphology clearly differed between both treatments at the end of the experiment, with aberrant shapes being observed only under the acidified conditions. On the other hand, while total organic matter was significantly higher under low pH conditions, no significant differences were detected between treatments regarding total carbohydrate, lipid, protein and fatty acid composition. However, the lower variability found among samples maintained in acidified conditions relative to controls, suggests a possible effect of pH decrease on the metabolism of the colonies. Our results show, for the first time, evidence of detrimental ocean acidification effects on this valuable and endangered coral species

Detrimental effects of Ocean Acidification on the economically important Mediterranean red coral (Corallium rubrum)

Bramanti, Lorenzo ... et al.-- 12 pages, 4 figures, 3 tables, supporting information additional may be found in the online version of this article: http://onlinelibrary.wiley.com/doi/10.1111/gcb.12171/suppinfoThe mean predicted decrease of 0.3 to 0.4 pH units in the global surface ocean by the end of the century has prompted urgent research to assess the potential effects of ocean acidification on the marine environment, with strong emphasis on calcifying organisms. Among them, the Mediterranean red coral (Corallium rubrum) is expected to be particularly susceptible to acidification effects, due to the elevated solubility of its Mg-calcite skeleton. This, together with the large overexploitation of this species, depicts a bleak future for this organism over the next decades. In this study, we evaluated the effects of low pH on this species from aquaria experiments. Several colonies of C. rubrum were long-term maintained for 314 days in aquaria at two different pH levels (8.10 and 7.81, pHT). Calcification rate, spicule morphology, major biochemical constituents (protein, carbohydrates and lipids) and fatty acids composition were measured periodically. Exposure to lower pH conditions caused a significant decrease in the skeletal growth rate in comparison to the control treatment. Similarly, the spicule morphology clearly differed between both treatments at the end of the experiment, with aberrant shapes being observed only under the acidified conditions. On the other hand, while total organic matter was significantly higher under low pH conditions, no significant differences were detected between treatments regarding total carbohydrate, lipid, protein and fatty acid composition. However, the lower variability found among samples maintained in acidified conditions relative to controls, suggests a possible effect of pH decrease on the metabolism of the colonies. Our results show, for the first time, evidence of detrimental ocean acidification effects on this valuable and endangered coral specieThe research has been funded by the EC 7th FP (grant agreement 265103, Project MedSeA) and by the Spanish Ministry of Economy and Competitiveness (MINECO; CTM2009-08849, Project ACDC). The authors are grateful for the invaluable support of the Cap de Creus Marine Protected Area staff. [...] L.B. was supported by a Marie Curie IEF fellowship (EC7th FP, Project nº 221072), J.M. by a FPI studentship (BES-2007-16537), M.G. by of Erasmus Mundus scolarship (contract no. JEMES European UAB 2009/No.3) and S.R. by a Ramón y Cajal Contract (RyC-2007-01327) from MINECO. US National Science Foundation grant OCE 08-44785 provided support to L.B. during part of the writing of manuscript. This is a contribution from the Marine Biogeochemistry and Global Change research group, funded by Generalitat de Catalunya through grant 2009SGR142Peer Reviewe

Effets néfastes de l'acidification des océans sur le corail rouge méditerranéen (Corallium rubrum), d'importance économique.

International audienceThe mean predicted decrease of 0.3–0.4 pH units in the global surface ocean by the end of the century has prompted urgent research to assess the potential effects of ocean acidification on the marine environment, with strong emphasis on calcifying organisms. Among them, the Mediterranean red coral (Corallium rubrum) is expected to be particularly susceptible to acidification effects, due to the elevated solubility of its Mg-calcite skeleton. This, together with the large overexploitation of this species, depicts a bleak future for this organism over the next decades. In this study, we evaluated the effects of low pH on the species from aquaria experiments. Several colonies of C. rubrum were long-term maintained for 314 days in aquaria at two different pH levels (8.10 and 7.81, pHT). Calcification rate, spicule morphology, major biochemical constituents (protein, carbohydrates and lipids) and fatty acids composition were measured periodically. Exposure to lower pH conditions caused a significant decrease in the skeletal growth rate in comparison with the control treatment. Similarly, the spicule morphology clearly differed between both treatments at the end of the experiment, with aberrant shapes being observed only under the acidified conditions. On the other hand, while total organic matter was significantly higher under low pH conditions, no significant differences were detected between treatments regarding total carbohydrate, lipid, protein and fatty acid composition. However, the lower variability found among samples maintained in acidified conditions relative to controls, suggests a possible effect of pH decrease on the metabolism of the colonies. Our results show, for the first time, evidence of detrimental ocean acidification effects on this valuable and endangered coral species.La diminution moyenne prédite de 0,3 à 0,4 unités de pH dans l'océan mondial en surface d'ici la fin du siècle a suscité des recherches urgentes pour évaluer les effets potentiels de l'acidification des océans sur l'environnement marin, mettant fortement l'accent sur les organismes calcifiants. Parmi eux, le corail rouge méditerranéen (Corallium rubrum) est susceptible d'être particulièrement affecté par les effets de l'acidification, en raison de la solubilité élevée de son squelette en Mg-calcite. Ceci, associé à la surpêche importante de cette espèce, dessine un avenir sombre pour cet organisme au cours des prochaines décennies. Dans cette étude, nous avons évalué les effets du faible pH sur l'espèce à partir d'expériences en aquarium. Plusieurs colonies de C. rubrum ont été maintenues à long terme pendant 314 jours dans des aquariums à deux niveaux de pH différents (8,10 et 7,81, pHT). Le taux de calcification, la morphologie des spicules, les principaux constituants biochimiques (protéines, glucides et lipides) et la composition en acides gras ont été mesurés périodiquement. L'exposition à des conditions de pH plus bas a entraîné une diminution significative du taux de croissance du squelette par rapport au traitement témoin. De même, la morphologie des spicules différait clairement entre les deux traitements à la fin de l'expérience, avec des formes aberrantes observées uniquement dans les conditions acidifiées. D'autre part, bien que la matière organique totale soit significativement plus élevée dans des conditions de faible pH, aucune différence significative n'a été détectée entre les traitements en ce qui concerne la composition totale en glucides, lipides, protéines et acides gras. Cependant, la variabilité plus faible trouvée parmi les échantillons maintenus dans des conditions acidifiées par rapport aux témoins suggère un possible effet de la diminution du pH sur le métabolisme des colonies. Nos résultats montrent, pour la première fois, des preuves d'effets néfastes de l'acidification des océans sur cette espèce de corail précieuse et menacée