Limited carbonate dissolution by boring microflora at two volcanically acidified temperate sites: Ischia (Italy, Mediterranean Sea) and Faial (Azores, NE Atlantic Ocean)

• Published in: Global Biogeochemical Cycles
• Main Authors: Tribollet, Aline, Grange, Julie, Parra, H., Rodolfo-Metalpa, Riccardo, Carreiro-Silva, Marina
• Other Authors: Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Marine and Environmental Sciences Centre Portugal (MARE), Instituto Universitário de Ciências Psicológicas, Sociais e da Vida = University Institute of Psychological, Social and Life Sciences (ISPA), Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE Nouvelle-Calédonie ), Institut de Recherche pour le Développement (IRD Nouvelle-Calédonie )-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), Marie-Curie IRG Fellowship to MC-S (CoralChange, project no 231109), the Regional Government of the Azores through the project OceanA-Lab (DRCT M.2.1.2/I/021/2011), Fundação para a Ciência e a Tecnologia post-doctoral grant (SFRH/BPD/34634/2007) and the strategic project (FCT/UID/MAR/04292/2013), project MIDACOR, European Project: 231109,EC:FP7:PEOPLE,FP7-PEOPLE-IRG-2008,CORALCHANGE(2009)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: aragonite and calcite substrates; CO 2 vents; temperate ecosystems; boring microalgae; biogenic dissolution; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; Ocean acidification
• Online Access: https://hal.science/hal-01686369; https://hal.science/hal-01686369/document; https://hal.science/hal-01686369/file/2016GB005575.pdf; https://doi.org/10.1002/2016GB005575

International audience In situ effects of ocean acidification on carbonate dissolution by microboring flora, also called biogenic dissolution, have only been studied once in tropical environments. Naturally acidified seawaters due to CO 2 vents offer a perfect setting to study these effects in temperate systems. Three sites were selected at Ischia (Italy, Mediterranean Sea) with one experiencing ambient pH and the two others a mean pH T of 7.2 and 7.5. At Faial (Azores, NE Atlantic), one site with ambient pH and one acidified site with a mean pH T of 7.4 were selected. Experiments were carried out during 1.5 months and 6 months in Azores and Ischia, respectively, to determine the effects of OA on microboring communities in various carbonate substrates. Low pH influenced negatively boring microflora development by limiting their depth of penetration and abundance in substrates. Biogenic dissolution was thus reduced by a factor 3 to 7 depending on sites and substrate types. At sites with ambient pH in Faial, biogenic dissolution contributed up to 23% to the total weight loss, while it contributed less than 1% to the total weight loss of substrates at the acidified sites. Most of the dissolution at these sites was due to chemical dissolution (often Ω ≤ 1). Such conditions maintained microboring communities at a pioneer stage with a limited depth of penetration in substrates. Our results, together with previous findings which showed an increase of biogenic dissolution at pH >7.7, suggest that there is a pH tipping point below which microborer development and thus, carbonate biogenic dissolution, is strongly limited.