title: Long-term mesocosms study of the effects of ocean acidification on growth and physiology of the sea urchin Echinometra mathaei.
abstract: Recent research on the impact of ocean acidification (OA) has highlighted that it is important to conduct long-term experiments including ecosystem interactions in order to better predict the possible effects of elevated pCO2. The goal of the present study was to assess the long-term impact of OA on a suite of physiological parameters of the sea urchin Echinometra mathaei in more realistic food conditions. A long-term experiment was conducted in mesocosms provided with an artificial reef in which the urchins principally fed on algae attached to the reef calcareous substrate. Contrasted pH conditions (pH 7.7 vs control) were established gradually over six months and then maintained for seven more months. Acid-base parameters of the coelomic fluid, growth and respiration rate were monitored throughout the experiment. Results indicate that E. mathaei should be able to regulate its extracellular pH at long-term, through bicarbonate compensation. We suggest that, within sea urchins species, the ability to accumulate bicarbonates is related to their phylogeny but also on the quantity and quality of available food. Growth, respiration rate and mechanical properties of the test were not affected. This ability to resist OA levels expected for 2100 at long-term could determine the future of coral reefs, particularly reefs where E. mathaei is the major bioeroder.
authors.affiliation: Laboratoire de Biologie Marine, Université Libre de Bruxelles, CP 160/15, Avenue F.D. Roosevelt 50, 1050 Bruxelles, Belgium; Laboratoire d'Ecologie Numérique des Milieux Aquatiques, Institut des Biosciences, Université de Mons, 23 Place du Parc, B7000 Mons, Belgium. Electronic address: lmoulin@ulb.ac.be.
authors.forename: Laure
authors.initials: L
authors.lastname: Moulin
authors.affiliation: Laboratoire d'Ecologie Numérique des Milieux Aquatiques, Institut des Biosciences, Université de Mons, 23 Place du Parc, B7000 Mons, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Grosjean
authors.affiliation: Laboratoire d'Ecologie Numérique des Milieux Aquatiques, Institut des Biosciences, Université de Mons, 23 Place du Parc, B7000 Mons, Belgium.
authors.forename: Julien
authors.initials: J
authors.lastname: Leblud
authors.affiliation: Laboratoire d'Ecologie Numérique des Milieux Aquatiques, Institut des Biosciences, Université de Mons, 23 Place du Parc, B7000 Mons, Belgium.
authors.forename: Antoine
authors.initials: A
authors.lastname: Batigny
authors.affiliation: Laboratoire de Biologie Marine, Université Libre de Bruxelles, CP 160/15, Avenue F.D. Roosevelt 50, 1050 Bruxelles, Belgium; Laboratory for Analytical, Environmental and Geo-Chemistry, Earth Systems Science Research Group, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Marie
authors.initials: M
authors.lastname: Collard
authors.affiliation: Laboratoire de Biologie Marine, Université Libre de Bruxelles, CP 160/15, Avenue F.D. Roosevelt 50, 1050 Bruxelles, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Dubois
mesh_terms: D000818:Animals; D057894:Coral Reefs; D006863:Hydrogen-Ion Concentration; D009792:Oceans and Seas; D010802:Phylogeny; D012617:Sea Urchins / Q000254:growth & development / Q000502:physiology*; D012623:Seawater / Q000737:chemistry*; D013045:Species Specificity
keywords: Acid–base regulation; Coral reefs; Echinometra mathaei; Growth; Long-term; Mesocosms; Metabolism; Ocean acidification; Sea urchins