title: Phosphorus retention and fractionation in an eutrophic wetland: A one-year mesocosms experiment under fluctuating flooding conditions.
abstract: This study aimed to evaluate the response of salt marshes to pulses of PO43--enriched water, with and without the presence of Phragmites australis. A one-year mesocosms experiment was performed in simulated soil profiles (fine-textured surface layers and sandy subsurface layers) from a coastal salt marsh of the Mar Menor lagoon under alternating flooding-drying conditions with eutrophic water, under low (1.95 mg L-1P-PO43-) and high (19.5 mg L-1P-PO43-) P load, and with the presence/absence of Phragmites. The PO43-concentrations in soil porewater and drainage water were regularly measured, and P accumulated in soils (including a fractionation procedure) and plants (roots, rhizomes, stems and leaves) were analyzed. The experimental mesocosms were highly effective in the removal of P from the eutrophic flooding water (>90% reduction of the P added to the system both in the soil pore water and drainage water), regardless of the nutrient load, the season of the year and the presence/absence of Phragmites. The soil was the main sink of the P added to the system, while Phragmites had a minor role in P removal. The biomass of Phragmites accumulated ∼27% of the P added with the flooding water in the treatment with water of low P load while ∼12% of P in that of high P load; the rhizomes were the organs that contributed the most (∼67-72% of the total P retained by the plants). Ca/Mg compounds were the main contributors to the retention of P in the soil compartment, especially in the fine-textured surface soil layers (∼34-53% of the total P in the soil was present in this fraction). Phragmites favored the retention of P onto metal oxides (∼12% increase of the P retained in the metal oxides fraction in the treatment with water of high P load). Hence, the use of constructed wetlands to ameliorate the negative impacts of P-enriched waters in the Mar Menor lagoon and similar areas is recommended. We propose the incorporation of fine-textured carbonated materials, with high content of Ca/Mg compounds, and the use of Phragmites to favor the retention of P by these systems.
authors.affiliation: Departamento de Ciencia y Tecnología Agraria, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Paseo Alfonso XIII 48, Cartagena, 30203, Murcia, Spain.
authors.forename: María Del Carmen
authors.initials: MDC
authors.lastname: Tercero
authors.affiliation: Departamento de Ciencia y Tecnología Agraria, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Paseo Alfonso XIII 48, Cartagena, 30203, Murcia, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Álvarez-Rogel
authors.affiliation: Departamento de Ciencia y Tecnología Agraria, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Paseo Alfonso XIII 48, Cartagena, 30203, Murcia, Spain.
authors.forename: Héctor Miguel
authors.initials: HM
authors.lastname: Conesa
authors.affiliation: Departamento de Ciencia y Tecnología Agraria, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Paseo Alfonso XIII 48, Cartagena, 30203, Murcia, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Párraga-Aguado
authors.affiliation: Departamento de Ciencia y Tecnología Agraria, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Paseo Alfonso XIII 48, Cartagena, 30203, Murcia, Spain. Electronic address: nazaret.gonzalez@upct.es.
authors.forename: María Nazaret
authors.initials: MN
authors.lastname: González-Alcaraz
mesh_terms: D018533:Biomass; D005068:Eutrophication; D055868:Floods; D010087:Oxides / Q000737:chemistry / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots; D018547:Plant Stems / Q000378:metabolism; D006109:Poaceae / Q000378:metabolism; D027343:Rhizome / Q000378:metabolism; D012621:Seasons; D012987:Soil / Q000737:chemistry; D013030:Spain; D014867:Water / Q000737:chemistry; D053833:Wetlands
chemical_list: D010087:Oxides; D010710:Phosphates; D012987:Soil; D014867:Water; D010758:Phosphorus
keywords: Green filters; Mar Menor lagoon; Phosphorus dynamics; Phragmites australis; Wetting-drying cycles