title: Stock and losses of trace metals from salt marsh plants.
abstract: Pools of Zn, Cu, Cd and Co in the leaf, stem and root tissues of Sarcocornia fruticosa, Sarcocornia perennis, Halimione portulacoides and Spartina maritima were analysed for a Tagus estuary (Portugal) salt marsh. Pools of Cu and Cd in the salt marsh were higher in spring/summer, indicating a net uptake of these metals during the growing season. Standing stocks of Zn, Cu, Cd and Co in the leaf and stem biomass of S. fruticosa, S. perennis and H. portulacoides showed a strong seasonal variation, with higher values recorded in autumn. The metal-containing leaves and stems that shed in the autumn become metal-containing detritus. The amount of this material washed out from the total marsh area (200 ha) was estimated as 68 kg of Zn, 8.2 kg of Cu, 13 kg of Co and 0.35 kg of Cd. The high tidal amplitude, a branched system of channels and semi-diurnal tidal cycle greatly favour the export of the organic detritus to adjoining marsh areas.
authors.affiliation: Institute of Oceanography, Faculty of Sciences, University of Lisbon, Rua Ernesto de Vasconcelos, Campo Grande 1749-016 Lisbon, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Caçador
authors.forename: Miguel
authors.initials: M
authors.lastname: Caetano
authors.forename: Bernardo
authors.initials: B
authors.lastname: Duarte
authors.forename: Carlos
authors.initials: C
authors.lastname: Vale
mesh_terms: D027703:Amaranthaceae / Q000254:growth & development / Q000378:metabolism*; D018533:Biomass; D002104:Cadmium / Q000032:analysis / Q000378:metabolism; D003035:Cobalt / Q000032:analysis / Q000378:metabolism; D003300:Copper / Q000032:analysis / Q000378:metabolism; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis; D019216:Metals, Heavy / Q000378:metabolism*; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D018547:Plant Stems / Q000254:growth & development / Q000378:metabolism; D006109:Poaceae / Q000254:growth & development / Q000378:metabolism*; D012621:Seasons; D053833:Wetlands; D015032:Zinc / Q000032:analysis / Q000378:metabolism
chemical_list: D019216:Metals, Heavy; D002104:Cadmium; D003035:Cobalt; D003300:Copper; D015032:Zinc