title: Organic matter quantity and quality, metals availability and foraminiferal assemblages as environmental proxy applied to the Bizerte Lagoon (Tunisia).
abstract: This study analyzes the benthic trophic state of Bizerte Lagoon (Tunisia) based on the total organic matter and the bioavailability of biopolymeric carbon including proteins (PTN), carbohydrates (CHO), lipids (LIP), chlorophyll a, as well as bacteria counts. The overall simultaneously extracted metals (SEM), and acid volatile sulfides (AVS) as well as the SEM/AVS ratio indicative of the toxicity of the sediments also were analyzed aiming to study their impact in the dimension, composition and structure of both dead and living benthic foraminiferal assemblages. In the studied sites TOC content is relatively high and the PTN/CHO values indicate that they can be considered as meso-eutrophic environments. The CHO/TOC and C/N values suggest that the OM which accumulated on the sediments surface has mainly natural origin despite the introduction of municipal and industrial effluents in the lagoon and the large bacterial pool. The living assemblages of benthic foraminifera of Bizerte Lagoon are quite different to other Mediterranean transitional systems studied until now. They are composed of typical lagoonal species but also include several marine and opportunistic species including significant numbers of bolivinids, buliminids, Nonionella/Nonionoides spp. and Cassidulina/Globocassidulina spp. These assemblages seem to benefitfrom the physicochemical parameters and the sediment stability. They may however face environmental stress in the lagoon related to the AVS production as a result of the organic matter degradation and toxicity in some areas due to the available concentrations of metals. Nonetheless statistical results evidence that the structure and dimension of assemblages are being controlled mostly by OM quantity and quality related mainly to the availability of PTN, CHO and chlorophyll a. Results of this work support the importance of considering OM quantity and quality in studies of environmental impact in coastal systems.
authors.affiliation: Universidade do Estado do Rio de Janeiro - UERJ, Faculdade de Geologia, Depto. de Paleontologia e Estratigrafia. Av. São Francisco Xavier, 524, Maracanã, 20550-013 Rio de Janeiro, RJ, Brazil; GeoBioTec, Departmento de Geosciencias, Universidade de Aveiro, 3810-193 Aveiro, Portugal. Electronic address: virginia.martins@ua.pt.
authors.forename: Maria Virgínia Alves
authors.initials: MV
authors.lastname: Martins
authors.affiliation: Laboratoire des Ressources Minérales et Environnement, Département de Géologie, Faculté des Sciences de Tunis, Campus Universitaire, 2092, Tunisia. Electronic address: he.amine@gmail.com.
authors.forename: Mohamed Amine
authors.initials: MA
authors.lastname: Helali
authors.affiliation: Institut National des Sciences et Technologies de la Mer, 1934-2025 Salammbô, Tunisia. Electronic address: nouri_zaaboub@yahoo.fr.
authors.forename: Noureddine
authors.initials: N
authors.lastname: Zaaboub
authors.affiliation: Institut National des Sciences et Technologies de la Mer, 1934-2025 Salammbô, Tunisia. Electronic address: imen.boukef@yahoo.fr.
authors.forename: Imen
authors.initials: I
authors.lastname: Boukef-BenOmrane
authors.affiliation: Università degli Studi di Urbino "Carlo Bo", Dipartimento di Scienze Pure e Applicate (DiSPeA), Campus Scientifico Enrico Mattei Località Crocicchia, 61029 Urbino, Italy. Electronic address: fabrizio.frontalini@uniurb.it.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Frontalini
authors.affiliation: Programa de Pós Graduação em Análises de Bacias e Faixas Móveis, Faculdade de Geologia, Universidade do Estado do Rio de Janeiro, Brazil. Electronic address: darllyreis@gmail.com.
authors.forename: Darlly
authors.initials: D
authors.lastname: Reis
authors.affiliation: Programa de Pós Graduação em Análises de Bacias e Faixas Móveis, Faculdade de Geologia, Universidade do Estado do Rio de Janeiro, Brazil. Electronic address: helenaportela@gmail.com.
authors.forename: Helena
authors.initials: H
authors.lastname: Portela
authors.affiliation: Programa de Pós Graduação em Análises de Bacias e Faixas Móveis, Faculdade de Geologia, Universidade do Estado do Rio de Janeiro, Brazil. Electronic address: iarammmc@hotmail.com.
authors.forename: Iara Martins Matos Moreira
authors.initials: IM
authors.lastname: Clemente
authors.affiliation: Programa de Pós Graduação em Análises de Bacias e Faixas Móveis, Faculdade de Geologia, Universidade do Estado do Rio de Janeiro, Brazil. Electronic address: leandronogueira5@gmail.com.
authors.forename: Leandro
authors.initials: L
authors.lastname: Nogueira
authors.affiliation: Universidade do Estado do Rio de Janeiro - UERJ, Faculdade de Geologia, Depto. de Paleontologia e Estratigrafia. Av. São Francisco Xavier, 524, Maracanã, 20550-013 Rio de Janeiro, RJ, Brazil. Electronic address: egberto@uerj.br.
authors.forename: Egberto
authors.initials: E
authors.lastname: Pereira
authors.affiliation: GeoBioTec, Departmento de Geosciencias, Universidade de Aveiro, 3810-193 Aveiro, Portugal. Electronic address: pfnmiranda@gmail.com.
authors.forename: Paulo
authors.initials: P
authors.lastname: Miranda
authors.affiliation: Institut National des Sciences et Technologies de la Mer, 1934-2025 Salammbô, Tunisia. Electronic address: monia.elbour@instm.rnrt.tn.
authors.forename: Monia
authors.initials: M
authors.lastname: El Bour
authors.affiliation: Université de Bourgogne Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS 6249, Place Leclerc, F-25030 Besançon Cedex, France. Electronic address: lotfi.aleya@univ-fcomte.fr.
authors.forename: Lotfi
authors.initials: L
authors.lastname: Aleya
mesh_terms: D002734:Chlorophyll; D000077194:Chlorophyll A; D004777:Environment; D004784:Environmental Monitoring / Q000379:methods*; D056908:Foraminifera / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry; D008670:Metals / Q000032:analysis*; D012623:Seawater / Q000737:chemistry; D013440:Sulfides; D014416:Tunisia; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008670:Metals; D013440:Sulfides; D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D000077194:Chlorophyll A
keywords: Acid volatile sulfides; Bacteria; Biopolymer concentrations; Chlorophyll a; Living benthic foraminifera; Oxygen isotopes; Simultaneously extracted metals; TOC