Pelagic primary production in the coastal Mediterranean Sea: variability, trends, and contribution to basin-scale budgets

• Published in: Biogeosciences
• Main Authors: Salgado-Hernanz, Paula, Maria, Regaudie-De-Gioux, Aurore, Antoine, David, Basterretxea, Gotzon
• Other Authors: Institut Mediterrani d'Estudis Avancats (IMEDEA), Consejo Superior de Investigaciones Cientificas = Spanish National Research Council (CSIC)-Universitat de les Illes Balears = Universidad de las Islas Baleares = University of the Balearic Islands (UIB), Centre Oceanogràfic de les Balears Palma, Spain (COB), Instituto Espagňol de Oceanografia (IEO), Consejo Superior de Investigaciones Cientificas = Spanish National Research Council (CSIC)-Consejo Superior de Investigaciones Cientificas = Spanish National Research Council (CSIC), Ecodéveloppement (ECODEVELOPPEMENT), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'Ecologie Pélagique (PELAGOS), Unité Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), 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), School of Earth and Planetary Sciences Perth, Curtin University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.sorbonne-universite.fr/hal-03522847; https://hal.sorbonne-universite.fr/hal-03522847/document; https://hal.sorbonne-universite.fr/hal-03522847/file/bg-19-47-2022.pdf; https://doi.org/10.5194/bg-19-47-2022

International audience We estimated pelagic primary production (PP) in the coastal (<200 m depth) Mediterranean Sea from satellite-borne data, its contribution to basin-scale carbon fixation, its variability, and long-term trends during the period 2002–2016. Annual coastal PP was estimated at 0.041 Gt C, which approximately represents 12 % of total carbon fixation in the Mediterranean Sea. About 51 % of this production occurs in the eastern basin, whereas the western and Adriatic shelves contribute with ∼25 % each of total coastal production. Strong regional variability is revealed in coastal PP, from high-production areas (>300 g C m−2) associated with major river discharges to less productive provinces (<50 g C m−2) located in the southeastern Mediterranean. PP variability in the Mediterranean Sea is dominated by interannual variations, but a notable basin-scale decline (17 %) has been observed since 2012 concurring with a period of increasing sea surface temperatures in the Mediterranean Sea and positive North Atlantic Oscillation and Mediterranean Oscillation climate indices. Long-term trends in PP reveal slight declines in most coastal areas (−0.05 to −0.1 g C m−2 per decade) except in the Adriatic where PP increases at +0.1 g C m−2 per decade. Regionalization of coastal waters based on PP seasonal patterns reveals the importance of river effluents in determining PP in coastal waters that can regionally increase up to 5-fold. Our study provides insight into the contribution of coastal waters to basin-scale carbon balances in the Mediterranean Sea while highlighting the importance of the different temporal and spatial scales of variability.