Effects of ocean acidification and diet on thickness and carbonate elemental composition of the test of juvenile sea urchins

• Published in: Marine Environmental Research
• Main Authors: Asnaghi, Valentina, Mangialajo, Luisa, Gattuso, Jean-Pierre, Francour, Patrice, Privitera, Davide, Chiantore, Mariachiara
• Other Authors: Department of Earth, Environmental and Life Sciences (DISTAV), Universita degli studi di Genova, Ecosystèmes Côtiers Marins et Réponses aux Stress (ECOMERS), Université Nice Sophia Antipolis (. - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Ocean acidification
• Online Access: https://hal.archives-ouvertes.fr/hal-03502775; https://doi.org/10.1016/j.marenvres.2013.08.005

Continuous anthropogenic CO2 emissions to the atmosphere and uptake by the oceans will cause a reduction of seawater pH and saturation state (Omega) of CaCO3 minerals from which marine calcifiers build their shells and skeletons. Sea urchins use the most soluble form of calcium carbonate, high-magnesium calcite, to build their skeleton, spines and grazing apparatus. In order to highlight the effects of increased pCO(2) on the test thickness and carbonate elemental composition of juvenile sea urchins and potential differences in their responses linked to the diet, we performed a laboratory experiment on juvenile Paracentrotus lividus, grazing on calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea, Dictyota dichotoma) macroalgae, under different pH (corresponding to pCO(2) values of 390, 550, 750 and 1000 mu atm). Results highlighted the importance of the diet in determining sea urchin size irrespectively of the pCO(2) level, and the relevance of macroalgal diet in modulating urchin Mg/Ca ratio. The present study provides relevant clues both in terms of the mechanism of mineral incorporation and in terms of bottom-up processes (algal diet) affecting top-down ones (fish predation) in rocky subtidal communities. (C) 2013 Elsevier Ltd. All rights reserved.