Oceanic mercury concentrations on both sides of the Strait of Gibraltar decreased between 1989 and 2012

• Main Authors: Cossa, Daniel, Knoery, Joël, Boye, Marie, Marusczak, Nicolas, Bastien, Thomas, Courau, Philippe, Sprovieri, Francesca
• Other Authors: Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement IRD : UR219-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Laboratoire de Science et Technologie de la Biomasse Marine, Nantes (IFREMER), Laboratoire de Science et Technologie de la Biomasse Marine, Biogéochimie et Ecotoxicologie (IFREMER BE), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), 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), Institute of Atmospheric Pollution Research (IIA), Consiglio Nazionale delle Ricerche Roma (CNR)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDE]Environmental Sciences; [SDU]Sciences of the Universe [physics]; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; North Atlantic; North East Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-02384726; https://hal.archives-ouvertes.fr/hal-02384726/document; https://hal.archives-ouvertes.fr/hal-02384726/file/Cossa%20et%20al%20in%20press%20ANTHROPOCENE.pdf

International audience Mercury (Hg) is a toxic metal that threatens the health of aquatic ecosystems and fish consumers. Its natural cycle has been deeply perturbed by anthropogenic Hg emissions, especially since the start of the Industrial Revolution circa 1850 AD. Anthropogenic Hg emissions from North America and Europe have decreased by a factor of two in the last decades following the implementation of strict regulations. The response of North Atlantic Ocean and Mediterranean waters to this decrease remains poorly documented by field observations. A comparison of results obtained between 1989 and 2012 shows a significant decrease of Hg concentrations in waters on both sides of the Strait of Gibraltar. West of Gibraltar, the Hg decrease ranges from ~35% in the upper North East Atlantic Deep Water to ~50% in the North East Atlantic Central Water. East of Gibraltar, the observed decrease is ~30% in the Western Mediterranean Deep Water. No decrease is observed in the deep Atlantic Ocean layer that formed before the industrial era. Our results strongly substantiate the effectiveness of global anti-pollution policies on Hg contamination in oceanic waters. Aconsequent decline of Hg bioaccumulation in Northeastern Atlantic and Western Mediterranean pelagic ecosystems is still to be verified.