title: Trace element storage capacity of sediments in dead Posidonia oceanica mat from a chronically contaminated marine ecosystem.
abstract: Posidonia oceanica mat is considered a long-term bioindicator of contamination. Storage and sequestration of trace elements and organic carbon (Corg) were assessed in dead P. oceanica mat and bare sediments from a highly polluted coastal marine area (Augusta Bay, central Mediterranean). Sediment elemental composition and sources of organic matter have been altered since the 1950s. Dead P. oceanica mat displayed a greater ability to bury and store trace elements and Corgthan nearby bare sediments, acting as a long-term contaminant sink over the past 120 yr. Trace elements, probably associated with the mineral fraction, were stabilized and trapped despite die-off of the overlying P. oceanica meadow. Mat deposits registered historic contamination phases well, confirming their role as natural archives for recording trace element trends in marine coastal environments. This sediment typology is enriched with seagrass-derived refractory organic matter, which acts mainly as a diluent of trace elements. Bare sediments showed evidence of inwash of contaminated sediments via reworking; more rapid and irregular sediment accumulation; and, because of the high proportions of labile organic matter, a greater capacity to store trace elements. Through different processes, both sediment typologies represent a repository for chemicals and may pose a risk to the marine ecosystem as a secondary source of contaminants in the case of sediment dredging or erosion. Environ Toxicol Chem 2017;36:49-58. © 2016 SETAC.
authors.affiliation: Department of Earth and Marine Sciences, University of Palermo, CoNISMa, Palermo, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Di Leonardo
authors.affiliation: Department of Earth and Marine Sciences, University of Palermo, CoNISMa, Palermo, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Mazzola
authors.affiliation: School of Environment and Technology, University of Brighton, Brighton, United Kingdom.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Cundy
authors.affiliation: Department of Earth and Marine Sciences, University of Palermo, CoNISMa, Palermo, Italy.
authors.forename: Cecilia Doriana
authors.initials: CD
authors.lastname: Tramati
authors.affiliation: Department of Earth and Marine Sciences, University of Palermo, CoNISMa, Palermo, Italy.
authors.forename: Salvatrice
authors.initials: S
authors.lastname: Vizzini
mesh_terms: D035961:Alismatales / Q000737:chemistry*; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D008522:Mediterranean Sea; D012802:Sicily; D014131:Trace Elements / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014131:Trace Elements; D014874:Water Pollutants, Chemical
keywords: Biogeochemical sink; Marine sediment; Mediterranean Sea; Seagrass mat; Trace element