High CO2 inhibits substratum exploration and settlement of coral larvae

• Published in: Marine Ecology Progress Series
• Main Authors: Jorissen, Hendrikje, Martin, Anaïs, Sarriboulette, Lauranne, Hédouin, Laetitia, Nugues, Maggy
• Other Authors: Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Paris Cité (UPCité), Université Bordeaux Montaigne, Laboratoire d'Excellence CORAIL (LabEX CORAIL), Institut de Recherche pour le Développement (IRD)-Université des Antilles et de la Guyane (UAG)-École des hautes études en sciences sociales (EHESS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de La Réunion (UR)-Université de la Polynésie Française (UPF)-Université de la Nouvelle-Calédonie (UNC)-Institut d'écologie et environnement-Université des Antilles (UA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Ocean acidification; Settlement; Recruitment; Coral larvae; Larvae behavior; Acropora; [SDV.BA]Life Sciences [q-bio]/Animal biology
• Online Access: https://hal-univ-perp.archives-ouvertes.fr/hal-03846493; https://doi.org/10.3354/meps14033

International audience Biological and physical factors affecting coral recruitment are critical in influencing the recovery of coral communities after disturbance. While ocean acidification (OA) can reduce coral settlement and the early growth of coral recruits, the impact of OA on coral larval swimming behavior is unknown. Here, we investigated the effects of elevated CO 2 on the swimming behavior and settlement of coral larvae of 2 common Acropora species. Larvae were exposed to 4 CO 2 partial pressure ( p CO 2 ) conditions consistent with the current Intergovernmental Panel for Climate Change predictions for the next few centuries ( p CO 2 : 393, 853, 1485 and 3022 µatm; pH: 8.1, 7.8, 7.6 and 7.3) in 2 laboratory experiments. We found that bottom exploration, expressed as the proportion of A. cytherea and A. pulchra larvae present in the bottom part of experimental cylinders, decreased by 92 and 98%, respectively, from the ambient to highest CO 2 treatment. When offered the choice to settle on the crustose coralline algae Titanoderma prototypum , a well-known positive settlement cue, the percentage of larvae that settled on the fragments declined rapidly as p CO 2 increased, with no larvae settling in the highest CO 2 treatment. These results suggest that OA may negatively affect coral recruitment via direct effects on larval swimming behavior, with larvae avoiding benthic probing in response to high CO 2 .