title: Seasonal variation and sources of dissolved trace metals in Maó Harbour, Minorca Island.
abstract: The environmental conditions of semi-enclosed coastal water-bodies are directly related to the catchment, human activities, and oceanographic setting in which they are located. As a result of low tidal forcing, and generally weak currents, waters in Mediterranean harbours are poorly renewed, leading to quality deterioration. Here, we characterise the seasonal variation of trace metals (i.e. Co, Cd, Cu, Fe, Mo, Ni, Pb, and Zn) in surface waters, and trace metal content in sediments from Maó Harbour, a semi-enclosed coastal ecosystem in the NW Mediterranean Sea. Our results show that most of the dissolved trace metals in the waters of Maó Harbour exhibit a marked inner-outer concentration gradient, suggesting a permanent input into the inner part of the harbour. In general, metal concentrations in the waters of Maó Harbour are higher than those in offshore waters. Concentration of Cu (21±8nM), Fe (9.2±3.2nM) and Pb (1.3±0.4nM) are particularly high when compared with other coastal areas of the Mediterranean Sea. The concentration of some metals such as Cu and Zn increases during summertime, when the human population and boat traffic increase during the tourism season, and when resuspension from the metal enriched sediments is higher. The evaluation of the metal sources in the harbour reveals that, compared with other putative sources such as runoff, aerosol deposition and fresh groundwater discharges, contaminated sediments are the main source of the metals found in the water column, most likely through vessel-driven resuspension events. This study contributes to the understanding of the processes that control the occurrence and distribution of trace metals in Maó Harbour, thus aiding in the effective management of the harbour, and enhancing the overall quality of the seawater ecosystem.
authors.affiliation: Department of Ecology and Marine Resources, Mediterranean Institute for Advanced Studies IMEDEA, Universidad de las Islas Baleares (UIB), Consejo Superior de Investigaciones Científicas (CSIC), Esporles, Spain. Electronic address: marly@imedea.uib-csic.es.
authors.forename: Marly C
authors.initials: MC
authors.lastname: Martínez-Soto
authors.affiliation: Department Ecology and Coastal Management, ICMAN-Instituto de Ciencias Marinas de Andalucía, Consejo Superior de Investigaciones Científicas (CSIC), Campus Universitario Río San Pedro, Puerto Real, Cádiz, Spain; Department of Global Change Research, Mediterranean Institute for Advanced Studies IMEDEA, Universidad de las Islas Baleares (UIB) - Consejo Superior de Investigaciones Científicas (CSIC), Esporles, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Tovar-Sánchez
authors.affiliation: Department of Global Change Research, Mediterranean Institute for Advanced Studies IMEDEA, Universidad de las Islas Baleares (UIB) - Consejo Superior de Investigaciones Científicas (CSIC), Esporles, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Sánchez-Quiles
authors.affiliation: Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Catalonia, Spain; Centre de Recherche et d'Enseignement de Géosciences de l'Environment CEREGE, Aix-Marseille Université, Aix-en-Provence, France.
authors.forename: Valentí
authors.initials: V
authors.lastname: Rodellas
authors.affiliation: Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Catalonia, Spain; Departament de Física, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Catalonia, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Garcia-Orellana
authors.affiliation: Department of Ecology and Marine Resources, Mediterranean Institute for Advanced Studies IMEDEA, Universidad de las Islas Baleares (UIB), Consejo Superior de Investigaciones Científicas (CSIC), Esporles, Spain.
authors.forename: Gotzon
authors.initials: G
authors.lastname: Basterretxea
mesh_terms: D004784:Environmental Monitoring / Q000379:methods; D019015:Geologic Sediments / Q000737:chemistry*; D008522:Mediterranean Sea; D012621:Seasons; D012623:Seawater / Q000737:chemistry*; D013030:Spain; D014131:Trace Elements / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014131:Trace Elements; D014874:Water Pollutants, Chemical
keywords: Groundwater discharge; Maó Harbour; Mediterranean Sea; Seawater; Sediments; Trace metals