title: Tidally driven N, P, Fe and Mn exchanges in salt marsh sediments of Tagus estuary (SW Europe).
abstract: Short-sediment cores and flooding water were collected at 0, 5, 15, 25 and 50 min of tidal inundation in the two sites colonised by pure stands of Spartina maritima (low marsh) and Sarcocornia fruticosa (high marsh) from the Rosário salt marsh (Tagus estuary, SW Europe). Concentrations of NH(4)(+), NO(3)(-) + NO(2)(-) and HPO (4)(2-), Fe and Mn were measured in tidal flooding water and pore water. Flooding water is enriched in nutrients, particularly ammonium due to local discharge of untreated urban effluents. Nevertheless, NH(4)(+) and NO(3)(-) + NO(2)(-) concentrations in flooding waters at t = 5 min (NH(4)(+) = 246 ± 7 μM, NO(3)(-) + NO(2)(-) = 138 ± 1 μM for S. fruticosa and NH(4)(+) = 256 ± 8 μM, NO(3)(-) + NO(2)(-) = 138 ± 1 μM for S. maritima) rose sharply at both vegetated sites. An increase was also registered for HPO(4)(2-) and total dissolved Fe although the subsequent decrease was smoother. Advective transport induced by the two daily pulses of inundation is several orders of magnitude higher than the diffusive fluxes during submerged periods. In addition, solutes are exported from the sediment with the inundation and imported in submerged periods. The exported amount of inorganic nitrogen during tidal inundation (export of 3,200 μmol N m(-2) day(-1)to the water column), is not counterbalanced by the sink of -290 μmol N m(-2) day(-1) occurred during the submerged period.
authors.affiliation: IPIMAR/INRB National Institute of Biological Resources, Av. Brasília, 1449-006 Lisbon, Portugal. mcaetano@ipimar.pt
authors.forename: M
authors.initials: M
authors.lastname: Caetano
authors.forename: P
authors.initials: P
authors.lastname: Bernárdez
authors.forename: J
authors.initials: J
authors.lastname: Santos-Echeandia
authors.forename: R
authors.initials: R
authors.lastname: Prego
authors.forename: C
authors.initials: C
authors.lastname: Vale
mesh_terms: D027703:Amaranthaceae / Q000254:growth & development; D004784:Environmental Monitoring; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry*; D007501:Iron / Q000032:analysis; D008345:Manganese / Q000032:analysis; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D006109:Poaceae / Q000254:growth & development; D011174:Portugal; D012623:Seawater / Q000737:chemistry; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*; D053833:Wetlands
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus; D008345:Manganese; D007501:Iron; D009584:Nitrogen
references.citation: Mar Environ Res. 2009 Mar;67(2):75-82
references.pmid: 19110308
references.citation: Geochem Trans. 2007 Jun 13;8:6
references.pmid: 17567893
references.citation: Environ Int. 2004 Jul;30(5):685-700
references.pmid: 15051245
references.citation: Environ Sci Technol. 2007 Nov 1;41(21):7376-82
references.pmid: 18044514
references.citation: Appl Environ Microbiol. 1995 Apr;61(4):1246-51
references.pmid: 7747947
references.citation: Sci Total Environ. 2008 Feb 15;390(2-3):466-74
references.pmid: 18036637
references.citation: Mar Environ Res. 2010 Dec;70(5):358-67
references.pmid: 20727578
references.citation: Sci Total Environ. 2007 Jul 15;380(1-3):84-92
references.pmid: 17320933