title: Nutrient regeneration susceptibility under contrasting sedimentary conditions from the Rio de Janeiro coast, Brazil.
abstract: Dissolved silicate (DSi), NH4(+), NO3(-) and PO4(3-) susceptibility to be exchanged between sediment pore waters and overlying waters was evaluated in Jurujuba Sound (JS station) and Coroa Grande Sound (CGS station), southeastern Brazil. Sedimentary elemental (C, N and P) and isotopic (δ(13)C and δ(15)N) compositions evidenced stronger anthropogenic fertilization in JS station. Net NO3(-) influxes from overlying waters occurred, which was two orders of magnitude higher under the more fertilized condition. This condition resulted in 6-13-times higher net effluxes of NH4(+), DSi and PO4(3-) to overlying waters. Vertical alternation between production and consumption processes in pore waters contributed for a more limited regeneration in CGS station. This was associated with diagenetic responses to sedimentary grain size variability in deeper layers and biological disturbance in upper layers. Nearly continuous production of NH4(+), DSi and PO4(3-) in pore waters implied in intensified susceptibility to remobilization under the eutrophic condition of JS station.
authors.affiliation: Programa de Geoquímica Ambiental, Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-150, Brazil. Electronic address: christienematos@hotmail.com.
authors.forename: Christiene R L
authors.initials: CR
authors.lastname: Matos
authors.affiliation: Programa de Geoquímica Ambiental, Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-150, Brazil. Electronic address: ursmendoza@geoq.uff.br.
authors.forename: Ursula
authors.initials: U
authors.lastname: Mendoza
authors.affiliation: Programa de Geoquímica Ambiental, Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-150, Brazil. Electronic address: ruca114@hotmail.com.
authors.forename: Rut
authors.initials: R
authors.lastname: Diaz
authors.affiliation: Programa de Geoquímica Ambiental, Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-150, Brazil. Electronic address: manuelmoreira@id.uff.br.
authors.forename: Manuel
authors.initials: M
authors.lastname: Moreira
authors.affiliation: Departamento de Engenharia Agrícola e do Meio Ambiente, Escola de Engenharia, Universidade Federal Fluminense, São Domingos, Niterói, RJ 24210-240, Brazil. Electronic address: andrebelem@id.uff.br.
authors.forename: Andre L
authors.initials: AL
authors.lastname: Belem
authors.affiliation: Laboratoire des Bio-Indicateurs Actuels et Fossiles, UMR6112 CNRS LPG-BIAF, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers Cedex, France. Electronic address: edouard.metzger@univ-angers.fr.
authors.forename: Edouard
authors.initials: E
authors.lastname: Metzger
authors.affiliation: Programa de Geoquímica Ambiental, Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-150, Brazil. Electronic address: ana_albuquerque@id.uff.br.
authors.forename: Ana Luiza S
authors.initials: AL
authors.lastname: Albuquerque
authors.affiliation: Programa de Geoquímica Ambiental, Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-150, Brazil. Electronic address: wmachado@geoq.uff.br.
authors.forename: Wilson
authors.initials: W
authors.lastname: Machado
mesh_terms: D001938:Brazil; D002244:Carbon / Q000032:analysis*; D005068:Eutrophication; D019015:Geologic Sediments / Q000737:chemistry*; D008962:Models, Theoretical; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis*; D012623:Seawater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen
keywords: Diagenesis; Eutrophication; Nutrients; Pore water; Remobilization modeling