Tracing anthropogenic aerosol trace metal sources in the North Atlantic Ocean using Pb, Zn and Ni isotopes

• Published in: Marine Chemistry
• Main Authors: Zhang, Xingchao, Lemaitre, Nolwenn, Rickli, Jörg Dominik, Suhrhoff, Tim Jesper, Shelley, Rachel, Benhra, Ali, Faye, Saliou, Jeyid, Mohamed Ahmed, Vance, Derek
• Other Authors: Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut National de Recherche Halieutique Casablanca, Maroc (INRH), Institut Sénégalais de Recherches Agricoles Dakar (ISRA), Institut Mauritanien de Recherches Océanographiques et des Pêches (IMROP)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: [SDE]Environmental Sciences; North Atlantic
• Online Access: https://hal.univ-brest.fr/hal-04417031; https://doi.org/10.1016/j.marchem.2023.104347

International audience Atmospheric deposition of trace metals of natural or anthropogenic origin is an important input of micronutrients to the surface ocean. However, understanding its direct impact on oceanic element cycles is challenging due to scarce data, coupled to diverse aerosol sources and variable solubilities. Here, we present a dataset that combines Ni, Zn and Pb isotopes for samples from the Moroccan and Senegalese coasts and in the high latitude North Atlantic Ocean. We combine the new with published data for other circum-North Atlantic sources to assess the processes that determine the isotope signatures in different types of aerosols. We then use open marine aerosol data to investigate the impact of these signatures in the open ocean. Isotope analyses were conducted on bulk aerosols (TSP), on their ultra-high-purity water leachates, and on rainwaters. Aerosols characterized by crustal elemental abundances have isotope compositions similar to Saharan mineral dust. Mixing with anthropogenic aerosols from Europe/North Africa results in lower Pb-206/Pb-207 and Pb-208/Pb-207 values for the Eastern North Atlantic region. Higher Pb-206/Pb-207 at a given Pb-208/Pb-207, observed near the Canadian margin and occasionally at the Senegalese coast, points to anthropogenic inputs from North America. Based on trends in the aerosol data (e.g., delta Zn-66(JMC-Lyon) versus Pb-206/Pb-207, delta Ni-60(SRM986) versus Ni/V), we identify several anthropogenic sources of Zn and Ni. The delta Zn-66(JMC-Lyon) of low-temperature pollution (e.g., non-exhaust traffic emission) appears to be around -0.1 parts per thousand to 0.2 parts per thousand, while leachate delta Zn-66(JMC-Lyon) as low as -0.21 parts per thousand indicates contributions from high-temperature combustion or smelting processes. Among aerosols with good correlations between Ni and V, delta Ni-60(SRM986) > 0.40 parts per thousand traces Ni contributions from oil combustion. Other Ni-enriched sources, possibly originating from laterite or sulfide, show ...