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In JoVE (1)
Other Publications (5)
Articles by Erika Magaletti in JoVE
JoVE General
Long-term Lethal Toxicity Test with the Crustacean Artemia franciscana
1Department of Environmental Quality Monitoring, Institute for Environmental Protection and Research, 2Regional Agency for Environmental Protection in Emilia-Romagna
This study concerns the development and standardization of a valuable methodological protocol to determine long-term (14 days) lethal toxicity exerted by chemical substances, industrial wastewater or sewage and liquid environmental samples on the saltwater crustacean, Artemia franciscana.
Other articles by Erika Magaletti on PubMed
Bacterial Uptake of DOM Released from P-limited Phytoplankton
The growth and the structure of a coastal bacterioplankton community were monitored in short-term bottle experiments in order to investigate the bacterial uptake of extracellular organic carbon released by the diatom Cylindrotheca closterium grown under P-balanced and P-depleted conditions. Bacterial specific growth rates and carbon demand were significantly lower in the exudates from P-depleted algae (24% and 30% reduction, respectively). The origin of the extracellular carbon appeared also to affect the taxonomic composition of the bacterioplankton assemblage, mainly reducing the development of gamma-Proteobacteria. This pattern of bacterial carbon uptake could contribute to a longer persistence of the exudates released in P-depleted conditions affecting the dynamics of the carbon cycle in marine environments.
Extracellular Carbohydrates Released by the Marine Diatoms Cylindrotheca Closterium, Thalassiosira Pseudonana and Skeletonema Costatum: Effect of P-depletion and Growth Status
A laboratory study was performed on the extracellular production of carbohydrates by the marine diatoms Cylindrotheca closterium, Thalassiosira pseudonana and Skeletonema costatum. The investigation was aimed at elucidating the role of P-starvation and growth status on abundance and chemical characteristics of the released non-attached polysaccharides. Inorganic phosphorus depletion determined an increase of total polysaccharides in all species examined compared to nutrient-replete (complete f/2) conditions. The highest abundance of polysaccharides per unit cell was found in T. pseudonana (28.4 micromol C 10(-6) cells), followed by C. closterium (2.56 micromol C 10(-6) cells) and S. costatum (1.18 micromol C 10(-6) cells). Maximum production rates were found at the transition between exponential and stationary growth phase. Gas-chromatographic analysis of the dissolved fraction showed glucose to be the most abundant monomer in exponentially growing, P-replete cultures (81.6%, 90% and 32% as molar percentage of total aldoses in C. closterium, T. pseudonana and S. costatum, respectively). A strong reduction in glucose was found in C. closterium, but not in T. pseudonana and S. costatum, under P-depleted conditions. Species-specific variations in the amount and aldose signatures of the released polysaccharides according to nutrient status and growth conditions can provide useful insights on the production and persistence of these organic compounds in the water column.
The Use of a Test Battery in Marine Ecotoxicology: the Acute Toxicity of Sodium Dodecyl Sulfate
For a toxicity assessment of substances entering the marine environment, it is preferable to carry out ecotoxicological tests on a base-set of taxa utilizing target species belonging to different trophic levels. In this study a battery composed of Vibrio fischeri (bacteria), Dunaliella tertiolecta (algae), Tigriopus fulvus (crustacea), Paracentrotus lividus (echinodermata), and Dicentrarchus labrax (pisces) was used for acute toxicity testing of sodium dodecyl sulfate (SDS). SDS is an anionic surfactant widely employed in industry, agriculture, and domestic usage and therefore is found in abundance in the environment, particularly in the sea. The mean values of EC50 obtained were 2.6, 4.8, 7.4, 3.2, 7.3 mg L(-1), respectively, for V. fischeri, D. tertiolecta, T. fulvus, P. lividus, and D. labrax. The results indicate the high acute toxicity of SDS with respect to all the trophic levels represented by the target species. In addition, they highlight the usefulness of employing a base-set of taxa rather than a single species in toxicological tests, in order to obtain more reliable information for the evaluation of toxicity and potential hazards to the marine environment of selected substances.
Toxicity Evaluation of Diethylene Glycol and Its Combined Effects with Produced Waters of Off-shore Gas Platforms in the Adriatic Sea (Italy): Bioassays with Marine/estuarine Species
Diethylene glycol (DEG) is commonly used to dehydrate natural gas in off-shore extraction plants and to prevent formation of gas hydrates. It may be released into the sea accidentally or in discharged produced waters (PWs). PWs samples from off-shore gas platforms in the Adriatic Sea (Italy) have been used in this study. The objectives of the study were: a) to evaluate the toxicity of DEG for marine organisms; b) to evaluate if a high DEG content in PWs may alter their toxicity; c) to verify whether the DEG threshold concentration established by the Italian legislation (3.5 g/l) for PWs discharged at sea is safe for marine environment. Ten different species (Vibrio fischeri, Phaeodactylum tricornutum, Dunaliella tertiolecta, Brachionus plicatilis, Artemia franciscana, Tigropus fulvus, Mytilus galloprovincialis, Crassostrea gigas, Tapes philippinarum and Dicentrarchus labrax) have been exposed to DEG; four of these species were also exposed to PWs in combination with DEG. The results showed that: a) DEG is not toxic at levels normally detected in Adriatic PWs; b) DEG in combination with PW showed mainly additive or synergistic effects; c) short-term bioassays showed that the DEG limit of 3.5 g/l could be acceptable.
Modulation of CYP1A and Genotoxic Effects in European Seabass (Dicentrarchus Labrax) Exposed to Weathered Oil: A Mesocosm Study
The aim of this study was to assess medium-term toxicity of weathered oil on European seabass. A mesocosm system reproducing an oil spill at sea was applied. Fish were collected after 48 h, 7, 30 and 60 days. Cyp1a gene transcription, EROD and UDPGT activities, bile PAHs metabolites and micronuclei frequency were investigated. A progressive disappearance of low molecular weight n-alkanes and PAHs in the water of the mesocosm occurred during the experimentation. Fishes exposed to oil displayed a significant increase of cyp1a expression and EROD activity during the entire experiment as well as higher concentrations of PAHs metabolites in bile. Micronulei frequency resulted significantly higher during all experiment in oil exposed sea bass compared to controls. The results highlight the environmental risk associated with the release of oil products at sea and confirm the adopted parameters as useful tools for studying the impact of accidental oil spills on fish.
