Time variability of the north-western Mediterranean Sea pH over 1995–2011

• Published in: Marine Environmental Research
• Main Authors: Marcellin Yao, Koffi, Marcou, Olivier, Goyet, Catherine, Guglielmi, Véronique, Touratier, Franck, Savy, Jean-Philippe
• Other Authors: Centre de Recherches Océanologiques Abidjan (CRO), Institut de Modélisation et d'Analyses en géo-environnement et santé - Espace Développement (IMAGES-Espace DEV), UMR 228 Espace-Dev, Espace pour le développement, Université de Guyane (UG)-Université des Antilles (UA)-Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Université de Guyane (UG)-Université des Antilles (UA)-Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Ocean acidification; Anthropogenic CO2; Mediterranean sea; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
• Online Access: https://hal-univ-perp.archives-ouvertes.fr/hal-01286093; https://doi.org/10.1016/j.marenvres.2016.02.016

International audience Factors controlling ocean acidification and its temporal variations were studied over the 1995–2011 period at the Dyfamed site at 10 m depth, in the North Mediterranean Sea. The results indicated a mean annual decrease of 0.003 ± 0.001 pH units on the seawater scale. The seasonal variability was characterized by a pH decrease during springtime and a strong pH increase in late fall. Anthropogenic CO2 (CANT) absorption by the ocean was the key driver of seawater acidification in this region, accounting for about 70% of the observed drop in pH, followed by water temperature (about 30%). The total inorganic carbon (CT) data showed a CT increase of 30.0 ± 1.0 μmol kg−1 per decade. This decadal increase is mainly due to the CANT penetration (43.2 μmol kg−1 per decade) in surface waters, which is mitigated for by relatively small opposing changes in CT due to physical and biological processes.