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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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  Volume de collection Numéro de collection Edition  
  ISSN 0045-6535 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2403  
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Auteur Ben Othman, H.; Leboulanger, C.; Le Floc'h, E.; Mabrouk, H.H.; Hlaili, A.S. url  doi
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  Titre Toxicity of benz(a)anthracene and fluoranthene to marine phytoplankton in culture: Does cell size really matter? Type Article scientifique
  Année 2012 Publication Revue Abrégée J. Hazard. Mater.  
  Volume 243 Numéro Pages 204-211  
  Mots-Clés Benz(a)anthracene; Ecotoxicity; Fluoranthene; Size-sensitivity relationship; aquatic organisms; biodegradation; chlorophyll; fluorescence; food-web; fresh-water phytoplankton; in-vitro; organic pollutants; pahs; phytoplankton; polycyclic aromatic-hydrocarbons; surface sediments  
  Résumé The toxicity of benz(a)anthracene and fluoranthene (polycyclic aromatic hydrocarbons, PAHs) was evaluated on seven species of marine algae in culture belonging to pico-, nano-, and microphytoplankton, exposed to increasing concentrations of up to 2 mg L-1. The short-term (24 h) toxicity was assessed using chlorophyll a fluorescence transients, linked to photosynthetic parameters. The maximum quantum yield Fv/Fm was lower at the highest concentrations tested and the toxicity thresholds were species-dependent. For acute effects, fluoranthene was more toxic than benz(a)anthracene, with LOECs of 50.6 and 186 mu g L-1, respectively. After 72 h exposure, there was a dose-dependent decrease in cell density, fluoranthene being more toxic than benz(a)anthracene. The population endpoint at 72 h was affected to a greater extent than the photosynthetic endpoint at 24 h. EC50 was evaluated using the Hill model, and species sensitivity was negatively correlated to cell biovolume. The largest species tested, the dinoflagellate Alexandrium catenella, was almost insensitive to either PAH. The population endpoint EC50s for fluoranthene varied from 54 mu g L-1 for the picophytoplankton Picochlorum sp. to 418 mu g L-1 for the larger diatom Chaetoceros muelleri. The size/sensitivity relationship is proposed as a useful model when there is a lack of ecotoxicological data on hazardous chemicals, especially in marine microorganisms. (C) 2012 Elsevier B.V. All rights reserved.  
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  Langue English Langue du Résumé Titre Original  
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  Volume de collection Numéro de collection Edition  
  ISSN 0304-3894 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 915  
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Auteur Ben Ouada, S.; Ben Ali, R.; Leboulanger, C.; Ben Ouada, H.; Sayadi, S. url  doi
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  Titre Effect of Bisphenol A on the extremophilic microalgal strain Picocystis sp. (Chlorophyta) and its high BPA removal ability Type Article scientifique
  Année 2018 Publication Revue Abrégée Ecotoxicology and Environmental Safety  
  Volume 158 Numéro Pages 1-8  
  Mots-Clés Biodegradation; Biotransformation; Bisphenol A; Extremophiles; Toxicity  
  Résumé Bisphenol A (BPA) effects and removal by an alkaliphilic chlorophyta, Picocystis, were assessed. BPA at low concentrations (0–25 mg L−1) did not inhibit the Picocystis growth and photosynthesis during 5 days of exposure. At higher BPA concentrations (50 and 75 mg L−1), the growth inhibition did not exceed 43%. The net photosynthetic activity was dramatically reduced at high BPA concentrations while, the PSII activity was less affected. The exposure to increasing BPA concentrations induced an oxidative stress in Picocystis cells, as evidenced by increased malondialdehyde content and the over-expression of antioxidant activities (ascorbate peroxydase, gluthation-S-transferase and catalase). Picocystis exhibited high BPA removal efficiency, reaching 72% and 40% at 25 and 75 mg L−1 BPA. BPA removal was ensured mainly by biodegradation/biotransformation processes. Based on these results, the extended tolerance and the high removal ability of Picocystis make her a promising specie for use in BPA bioremediation.  
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  Volume de collection Numéro de collection Edition  
  ISSN 0147-6513 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2329  
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Auteur Ben-Gharbia, H.; Yahia, O.K.-D.; Amzil, Z.; Chomerat, N.; Abadie, E.; Masseret, E.; Sibat, M.; Triki, H.Z.; Nouri, H.; Laabir, M. doi  openurl
  Titre Toxicity and Growth Assessments of Three Thermophilic Benthic Dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) Developing in the Southern Mediterranean Basin Type Article scientifique
  Année 2016 Publication Revue Abrégée Toxins  
  Volume 8 Numéro 10 Pages 297  
  Mots-Clés coastal waters; Coolia monotis; environmental-factors; growth; gulf-of-california; harmful algal blooms; marine dinoflagellate; multiple sequence alignment; new-zealand; okadaic acid; Ostreopsis cf. ovata; Prorocentrum lima; Southern Mediterranean Sea; sp-nov dinophyceae; toxicity; toxin profile  
  Résumé Harmful benthic dinoflagellates, usually developing in tropical areas, are expanding to temperate ecosystems facing water warming. Reports on harmful benthic species are particularly scarce in the Southern Mediterranean Sea. For the first time, three thermophilic benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) were isolated from Bizerte Bay (Tunisia, Mediterranean) and monoclonal cultures established. The ribotyping confirmed the morphological identification of the three species. Maximum growth rates were 0.59 +/- 0.08 d(-1) for O. cf. ovata, 0.35 +/- 0.01 d(-1) for C. monotis and 0.33 +/- 0.04 d(-1) for P. lima. Toxin analyses revealed the presence of ovatoxin-a and ovatoxin-b in O. cf. ovata cells. Okadaic acid and dinophysistoxin-1 were detected in P. lima cultures. For C. monotis, a chromatographic peak at 5.6 min with a mass m/z = 1061.768 was observed, but did not correspond to a mono-sulfated analogue of the yessotoxin. A comparison of the toxicity and growth characteristics of these dinoflagellates, distributed worldwide, is proposed.  
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  Volume de collection Numéro de collection Edition  
  ISSN 2072-6651 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1690  
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Auteur Boukef, I.; El Bour, M.; Al Gallas, N.; El Bahri, O.; Mejri, S.; Mraouna, R.; Ben Aissa, R.; Boudabous, A.; Got, P.; Troussellier, M. url  doi
openurl 
  Titre Survival of Escherichia coli Strains in Mediterranean Brackish Water in the Bizerte Lagoon in Northern Tunisia Type Article scientifique
  Année 2010 Publication Revue Abrégée Water Environ Res  
  Volume 82 Numéro 11 Pages 2249-2257  
  Mots-Clés bizerte lagoon; brackish water; coastal waters; cytotoxicity; enteric bacteria; escherichia coli; fecal-coliforms; marine waters; salmonella-typhimurium; seawater microcosms; sewage; shigella-dysenteriae type-1; sunlight; survival; viability; virulence  
  Résumé This study investigated survival and virulence of Escherichia coli strains exposed to natural conditions in brackish water. Two E. coli strains (O126:B16 and O55:B5) were incubated in water microcosms in the Bizerte lagoon in Northern Tunisia and exposed for 12 days to natural sunlight in June (231 to 386 W/m(2), 26 +/- 1 degrees C, 30 g/L) and in April (227 to 330 W/m(2), 17 +/- 1 degrees C, 27 g/L) or maintained in darkness for 21 days (17 +/- 1 degrees C, 27 g/L). The results revealed that sunlight was the most significant inactivating factor (decrease of 3 Ulog within 48 hours for the two strains) compared to salinity and temperature (in darkness). Survival time of the strains was prolonged as they were maintained in darkness. Local strain (E. coli O55:B5) showed better survival capacity (T(90) = 52 hours) than E. coli O126:B16 (T(90) = 11 h). For both, modifications were noted only for some metabolic activities of carbohydrates hydrolysis. Cytotoxicity of the two strains, tested on Vero cell, was maintained during the period of survival. Water Environ. Res., 82, 2249 (2010).  
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  ISSN 1061-4303 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 864  
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