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Auteur Le Fur, I.; De Wit, R.; Plus, M.; Oheix, J.; Simier, M.; Ouisse, V. doi  openurl
  Titre Submerged benthic macrophytes in Mediterranean lagoons: distribution patterns in relation to water chemistry and depth Type Article scientifique
  Année 2018 Publication Revue Abrégée Hydrobiologia  
  Volume 808 Numéro 1 Pages 175-200  
  Mots-Clés southern france; eutrophication; coastal lagoon; Eutrophication; Depth; Salinity; environmental-factors; seagrass; aquatic vegetation; Canonical correspondence analysis (CCA); canonical correspondence-analysis; French coastal lagoons; potamogeton-pectinatus; spatiotemporal dynamics; Submerged aquatic vegetation (SAV); thau-lagoon  
  Résumé A large spectrum of coastal lagoon types with a wide range of environmental conditions is observed along the French Mediterranean coast. These comprise wide trophic and salinity gradients, ranging from oligotrophic to hypertrophic status, and from nearly freshwater to slightly above marine Mediterranean Sea water salinities, respectively. The statistical analysis of a long-term dataset, including water column variables and observations of macrophyte genera, showed that salinity, depth, and then trophic status, were important factors explaining the distribution of benthic macrophytes for the soft-bottom sediments in the 34 studied French Mediterranean lagoons. Based on this, we assumed that the vegetation succession along the eutrophication gradient was different according to the lagoon salinity ranges. Euhaline and polyhaline lagoons follow the well-known Schramm schematic model, where aquatic angiosperm such as seagrasses dominate under oligotrophic conditions, and opportunistic macroalgae and phytoplankton dominate under eutrophic and hypertrophic conditions. In oligohaline and mesohaline lagoons, the succession is probably an intermediate scheme between the successions observed in small temperate lakes and in marine coastal ecosystems due to the presence of both brackish and freshwater species. We thus propose a conceptual scheme for the oligohaline and mesohaline lagoons.  
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  ISSN (up) 0018-8158 ISBN Médium  
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Auteur Fiandrino, A.; Ouisse, V.; Dumas, F.; Lagarde, F.; Pete, R.; Malet, N.; Le Noc, S.; de Wit, R. doi  openurl
  Titre Spatial patterns in coastal lagoons related to the hydrodynamics of seawater intrusion Type Article scientifique
  Année 2017 Publication Revue Abrégée Mar. Pollut. Bull.  
  Volume 119 Numéro 1 Pages 132-144  
  Mots-Clés bay; confinement; estuary; Hydromorphological zonations; Mediterranean coastal lagoons; Mixing efficiency; model performance; Numerical model; sparus-aurata; Transport timescale; transport time scales; ulva rigida; venice lagoon; Water renewal; water renewal timescales; wind-driven circulation  
  Résumé Marine intrusion was simulated in a choked and in a restricted coastal lagoon by using a 3D-hydrodynamic model. To study the spatiotemporal progression of seawater intrusion and its mixing efficiency with lagoon waters we define Marine Mixed Volume (V-MM) as a new hydrodynamic indicator. Spatial patterns in both lagoons were described by studying the time series and maps of VMM taking into account the meteorological conditions encountered during a water year. The patterns comprised well-mixed zones (WMZ) and physical barrier zones (PBZ) that act as hydrodynamic boundaries. The choked Bages-Sigean lagoon comprises four sub-basins: a PBZ at the inlet, and two WMZ's separated by another PBZ corresponding to a constriction zone. The volumes of the PBZ were 2.1 and 5.4 millions m(3) with characteristic mixing timescale of 68 and 84 days, respectively. The WMZ were 123 and 433 millions m(3) with characteristics mixing timescale of 70 and 39 days, respectively. (C) 2017 Elsevier Ltd. All rights reserved.  
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  ISSN (up) 0025-326x ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2181  
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Auteur Ben Othman, H.; Lanouguère, É.; Got, P.; Sakka Hlaili, A.; Leboulanger, C. url  doi
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  Titre Structural and functional responses of coastal marine phytoplankton communities to PAH mixtures Type Article scientifique
  Année 2018 Publication Revue Abrégée Chemosphere  
  Volume 209 Numéro Pages 908-919  
  Mots-Clés Ecotoxicity; Mediterranean coastal lagoons; PAH mixtures (PAHs); Phytoplankton communities  
  Résumé The toxicity of polycyclic aromatic hydrocarbons (PAHs) mixtures was evaluated on natural phytoplankton communities sampled from lagoons of Bizerte (South-western Mediterranean Sea) and Thau (North-western Mediterranean Sea). PAHs induced short-term dose and ecosystem-dependant decreases in photosynthetic potential. Chlorophyll a was negatively affected by increasing PAHs concentrations, together with dramatic changes in phytoplankton community composition. Size classes were strongly affected in the Bizerte compare to the Thau lagoon, with a decrease in nano- and microphytoplankton densities compare to picophytoplankton. In both locations, the diatom Entomoneis paludosa appeared favoured under PAH exposure as evidenced by increase in cell density, whereas autotrophic flagellates and dinophytes were strongly reduced. Smaller cells were more tolerant to exposure to highest PAHs concentrations, with persistent picophytoplankton carbon biomass at the end of the incubations. Apparent recovery of photosynthetic potential, accompanied with a regrowth of chlorophyll a under the lowest PAH doses, coincided with a significantly altered community composition in both lagoons. Furthermore, sensitivity to PAHs was not related to the phytoplankton cell size, and toxicity-induced modification of top-down control by grazers during the experiment cannot be excluded.  
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  ISSN (up) 0045-6535 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2403  
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Auteur Draredja, M.A.; Frihi, H.; Boualleg, C.; Gofart, A.; Abadie, E.; Laabir, M. doi  openurl
  Titre Seasonal variations of phytoplankton community in relation to environmental factors in a protected meso-oligotrophic southern Mediterranean marine ecosystem (Mellah lagoon, Algeria) with an emphasis of HAB species Type Article scientifique
  Année 2019 Publication Revue Abrégée Environ. Monit. Assess.  
  Volume 191 Numéro 10 Pages 603  
  Mots-Clés coastal lagoons; Diversity; dynamics; Environmental conditions; HAB species; Mediterranean lagoon; nutrients; particulate matter; patterns; Phytoplankton monitoring; sea; temporal variations; thau lagoon; venice lagoon; water-quality  
  Résumé The spatial and temporal variation of phytoplankton communities including HAB species in relation to the environmental characteristics was investigated in the protected meso-oligotrophic Mellah lagoon located in the South Western Mediterranean. During 2016, a biweekly monitoring of phytoplankton assemblages and the main abiotic factors were realized at three representative stations. Taxonomic composition, abundance, and diversity index were determined. In total, 227 phytoplankton species (160 diatoms and 53 dinoflagellates) were inventoried. There was a clear dominance of diatoms (62.9%) compared with dinoflagellates (36.8%). Diatoms dominated in spring and dinoflagellates developed in summer and early autumn in Mellah showing a marked seasonal trend. Data showed that the dynamic of the phytoplankton taxa evolving in the lagoon was mainly driven by temperature and salinity. For the first time, a number of potentially toxic species have been identified, including 2 diatoms (Pseudo-nitzschia group delicatissima, Pseudo-nitzschia group seriata) and 5 dinoflagellates (Alexandrium minutum, Alexandrium tamarense/catenella, Dinophysis acuminata, Dinophysis sacculus, Prorocentrum lima). These harmful species could threat the functioning of the Mellah lagoon and human health and require the establishment of a monitoring network. Finally, our study suggests that the observed decrease of the phytoplankton diversity between 2001 and 2016 could result from the reduction in water exchanges between the lagoon and the adjacent coast following the gradual clogging of the channel.  
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  ISSN (up) 0167-6369 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2635  
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Auteur Leruste, A.; Malet, N.; Munaron, D.; Derolez, V.; Hatey, E.; Collos, Y.; De Wit, R.; Bec, B. url  doi
openurl 
  Titre First steps of ecological restoration in Mediterranean lagoons: Shifts in phytoplankton communities Type Article scientifique
  Année 2016 Publication Revue Abrégée Estuarine, Coastal and Shelf Science  
  Volume 180 Numéro Pages 190-203  
  Mots-Clés Coastal lagoons; Nutrient; Phytoplankton; Re-oligotrophication; Sewage effluents  
  Résumé Along the French Mediterranean coast, a complex of eight lagoons underwent intensive eutrophication over four decades, mainly related to nutrient over-enrichment from continuous sewage discharges. The lagoon complex displayed a wide trophic gradient from mesotrophy to hypertrophy and primary production was dominated by phytoplankton communities. In 2005, the implementation of an 11 km offshore outfall system diverted the treated sewage effluents leading to a drastic reduction of anthropogenic inputs of nitrogen and phosphorus into the lagoons. Time series data have been examined from 2000 to 2013 for physical, chemical and biological (phytoplankton) variables of the water column during the summer period. Since 2006, total nitrogen and phosphorus concentrations as well as chlorophyll biomass strongly decreased revealing an improvement in lagoon water quality. In summertime, the decline in phytoplankton biomass was accompanied by shifts in community structure and composition that could be explained by adopting a functional approach by considering the common functional traits of the main algal groups. These phytoplankton communities were dominated by functional groups of small-sized and fast-growing algae (diatoms, cryptophytes and green algae). The trajectories of summer phytoplankton communities displayed a complex response to changing nutrient loads over time. While diatoms were the major group in 2006 in all the lagoons, the summer phytoplankton composition in hypertrophic lagoons has shifted towards green algae, which are particularly well adapted to summertime conditions. All lagoons showed increasing proportion and occurrence of peridinin-rich dinophytes over time, probably related to their capacity for mixotrophy. The diversity patterns were marked by a strong variability in eutrophic and hypertrophic lagoons whereas phytoplankton community structure reached the highest diversity and stability in mesotrophic lagoons. We observe that during the re-oligotrophication process in coastal lagoons, phytoplankton shows complex trajectories with similarities with those observed in freshwater lake systems.  
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  ISSN (up) 0272-7714 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1598  
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