Ermelinda Prato

Standardized methods for acute and semichronic toxicity tests with the copepod Acartia tonsa

The availability of standardized protocols for both organism culture and bioassay with ecologically relevant species is of great concern in ecotoxicology. Acartia tonsa represents an important, often dominant, member of zooplankton communities and meets all the practical criteria suggested for model species. New standardized procedures for laboratory culturing of the copepod A. tonsa and standardized methods for acute (24- and 48-h) and semichronic (7-d, static-renewal) toxicity tests with the nauplius stage are described. In both cases, eggs are the starting stage, and nauplius immobilization is the endpoint. The methods were the object of an intercomparison test involving nine laboratories, and nickel was the reference toxicant. Relative reproducibility was 24, 25, and 34% for 24-h, 48-h, and 7-d tests, respectively.

A test battery approach for ecotoxicological characterization of Mar Piccolo sediments in Taranto (Ionian Sea, Southern Italy)

The eco-toxicological approach is based on the determination of the toxic effects on organisms pertaining to various ecosystems and supplies information about the contaminants mixture bioavailability, in complex matrices as sediments. The use of a single species for a correct evaluation of the toxicity levels can be reductive, concerning the complexity of the ecosystem. In this work we have used species with various evolutionary levels and habitats; in particular, three different organisms: two amphipods species (Corophium insidiosum and Gammarus aequicauda) and one bacterium Vibrio fischeri. We have compared these organisms for the evaluation of sediments toxicity in four sites along the Ionian coast (Taranto, Italy); in particular, three sites in Mar Piccolo and one site in Mar Grande. The toxicity of sediments measured using Vibrio fischeri (Microtox® Solid Phase Test protocol) has been compared with the mortality of the two amphipods. Both in polluted (Mar Piccolo sites) and in non-polluted environments (Mar Grande), the results of the three biological tests carried out converge into the evaluation of sediments quality monitored. In conclusion, these preliminary results show the potential use of Corophium insidiosum and Gammarus aequicauda as test species for a correct evaluation of sediments quality, together with Vibrio fischeri.

Factors influencing the sensitivity of Gammarus aequicauda population from Mar Piccolo in Taranto (Southern Italy).

Laboratory experiments were performed on the amphipod Gammarus aequicauda in order to evaluate the relationship between the seasonal sensitivity to a reference toxicant and seasonal lipid content, temperature and algal biomass. The organisms were collected in a clean site in the Mar Piccolo of Taranto (Ionian sea) from March 2003 to February 2004. The total lipid content of G. aequicauda varied from 5.5% in spring to a maximum of 19% in autumn, then decreased until reaching 9.8% of dry weight in winter. Triacyglycerols (TG) were the most abundant lipid class in G. aequicauda, except in spring, when there was a higher percentage of phospholipids (PL). Sterol levels were lower. The sensitivity of G. aequicauda during different seasons was significantly affected by total lipids (r=0.97; p<0.01), but no relationship was found with algal biomass (r=0.21; p>0.05) and temperature (r=0.29; p>0.05). The highest LC(50) values appeared with an increase of total lipids. This study will be used to improve the interpretation of ecotoxicological test results with G. aequicauda.

Gammarus aequicauda (Crustacea: Amphipoda): A potential test species in marine sediment toxicity assessment

In this study, the amphipod Gammarus aequicauda was evaluated as a test organism for use in sediment toxicity bioassays. Sensitivity to noncontaminant variables, to the reference toxicants and to some contaminated field sediments was analysed. Amphipods were tolerant to various salinity and temperature combinations during a ten-day assay. The organisms tested with different type of diet showed highest survival on the natural diet. The organism density effect on survival and growth of Gammarus aequicauda during a 28-day assay was examined. The results indicated that the density did not affect survival and production, but the effect of density was significant on the average weight. No effect on survival was observed on three sediment types during the 10-day exposure. Sensitivity to contaminants was assessed using cadmium chloride and copper chloride as reference toxicants in a 96 h water-only test. Methods were developed for conducting a short-term toxicity test with cadmium chloride-spiked sediment using this species. Water-only testing revealed high sensitivity of amphipods to reference toxicants. Experiments conducted with organisms of four different size classes demonstrated no significant differences in sensitivity.

A preliminary investigation of the lipids and fatty acids composition of Gammarus aequicauda (Crustacea: Amphipoda) and its main food source

Lipid and fatty acid composition in Gammarus aequicauda from Mar Piccolo (Ionian Sea, southern Italy) were studied during the spring months. Simultaneously, samples of the macroalgae Chaetomorpha linum were also collected from the same area. During these months Chaetomorpha linum was the main food source of Gammarus aequicauda . The main lipid classes were phospholipids (PL) and triacylglycerols (TG) both in Gammarus aequicauda and in Chaetomorpha linum with similar concentrations. But PL was the main lipid class in Gammarus aequicauda and TG in Chaetomorpha linum . On average unsaturated fatty acids represent the preponderant part in both G. aequicauda and C. linum . Gammarus aequicauda had a higher level in monounsaturated fatty acids (MUFA), on the contrary polyunsaturated fatty acids (PUFA) were the dominant unsaturated fatty acids in C. linum. Both were characterized by high levels of 18:0, 18:1(n-9), 20:5(n-3) and 20:4(n-6), in particular C. linum had a high proportion of 14:0 and the ratio of 18:1n 9/18:1n 7 was high.

Effects of nanoparticles in species of aquaculture interest

AbstractRecently, it was observed that there is an increasing application of nanoparticles (NPs) in aquaculture. Manufacturers are trying to use nano-based tools to remove the barriers about waterborne food, growth, reproduction, and culturing of species, their health, and water treatment in order to increase aquaculture production rates, being the safe-by-design approach still unapplied. We reviewed the applications of NPs in aquaculture evidencing that the way NPs are applied can be very different: some are direclty added to feed, other to water media or in aquaculture facilities. Traditional toxicity data cannot be easily used to infer on aquaculture mainly considering short-term exposure scenarios, underestimating the potential exposure of aquacultured species. The main outputs are (i) biological models are not recurrent, and in the case, testing protocols are frequently different; (ii) most data derived from toxicity studies are not specifically designed on aquaculture needs, thus contact time, exposure concentrations, and other ancillary conditions do not meet the required standard for aquaculture; (iii) short-term exposure periods are investigated mainly on species of indirect aquaculture interest, while shrimp and fish as final consumers in aquaculture plants are underinvestigated (scarce or unknown data on trophic chain transfer of NPs): little information is available about the amount of NPs accumulated within marketed organisms; (iv) how NPs present in the packaging of aquacultured products can affect their quality remained substantially unexplored. NPs in aquaculture are a challenging topic that must be developed in the near future to assure human health and environmental safety. Graphical abstractᅟ

Comparison of amphipods Corophium insidiosum and C. orientale (Crustacea: Amphipoda) in sediment toxicity testing

The aim of this study was to compare the sensitivity of two Corophidae: Corophium orientale a standardized species and Corophium insidiosum a species more available in the Ionian sea (Southern Italy), in order to evaluate the suitability and applicability of C. insidiosum to sediment toxicity test. The sensitivity of the 2 species was compared through simultaneous bioassays: the 96-h static water-only toxicity test and a 10-day static sediment toxicity test. Sediment samples were collected in the Livorno harbour (Ligurian Sea). Both amphipods showed high sensitivity to reference toxicant and no significant differences were found between the two Corophiidae (t test; p > 0.05). Numerical Sediment Quality Guidelines (SQGs) have been used to relate the chemical concentrations of sediment samples to biological effects. Both amphipod species indicated the same sediment samples as potentially toxic according to chemical data. The results indicate that Corophium insidiosum would be suitable as an alternative test species to the recommended species C. orientale, in the development of sediment toxicity test.

Preliminary investigation on the phytoplankton contribution to the mussel diet on the basis of fatty acids analysis

The composition of fatty acids was studied in the mussels collected in the Mar Grande of Taranto (northern Ionian Sea) during the four seasons. Micro-, nano- and picophytoplankton abundance, biomass and composition have been also evaluated. Fatty acids compositions were investigated for lipid biomarkers to establish the contribution of phytoplankton to the mussel diet. Saturated (SAFA) and monounsaturated fatty acids (MUFA) were the most abundant components, followed by polyunsaturated fatty acids (PUFA). The seasonal variations in the SAFAs, MUFAs and PUFAs were not significantly different during the whole study period (ANOVA, P < 0.05,). The most abundant identified FAs were 16:0 (27.51-33.80% of total FAs), 14:1 (3.35-9.91% of total FAs), 18:in9 (2.92-8.87%), 16:1 n7 (4.53- 7.61%) and 24:1n9 (0.43-8.84%). The most important PUFAs were 22:2 (2.35-3.48% of total FAs) and also 18:2n-6 (1.66-2.61%). PUFAs were characterized by low percentages of n3 and n6 FAs. Analysis of specific FA markers for diatoms (16:1n7, 20:5n3) , phytoflagellates and dino- flagellates (16:0, 18:4n3) showed a negligible contribution of phytoplankton to the mussel diet.

Evaluation of a bioassays battery for ecotoxicological screening of marine sediments from Ionian Sea (Mediterranea Sea, Southern Italy).

Sediments are an ecologically important component of the aquatic environment and may play a key role in mediating the exchange of contaminants between particulate, dissolved, and biological phases. For a comprehensive assessment of potential sediment toxicity, the use of a single species may not detect toxicant with a specific mode of action. Therefore it is advisable to carry out ecotoxicological tests on a base-set of taxa utilizing test species belonging to different trophic levels. This paper describes the ecotoxicological evaluation of marine sediments from seven sites of Mar Piccolo estuary (Southern, Italy), four of them were located in the first inlet and three in the second inlet of Mar Piccolo estuary. Sediment samples from a site in Taranto Gulf were used as control sediment. Dunaliella tertiolecta, Tigriopus fulvus, Mytilus galloprovincialis, and Corophium insidiosum, were employed to identify the quality of sediments. The integration of biological tests results showed that all sampling sites located in the first inlet of Mar Piccolo were identified as toxic, according to all tests, while the sites of second inlet were found not toxic. The results obtained in this study indicate that the use of a battery of biological tests have important implications for risk assessment in estuarine e coastal waters.

Life history of Talorchestia deshayesii (Amphipoda, Talitridae) in the Ionian sandy beach (southern Italy)

The population structure and reproductive biology of Talorchestia deshayesii (Audouin, 1826) on an exposed sandy beach in Taranto (Italy) was examined during one year cycle. Monthly surveys were performed from September 2002 to August 2003. Individuals were subdivided into sex, measured and abundance were calculated for each sampling. Abundance varied during the study period, with a marked decrease in winter. T. deshayesii, was found in a relative narrow zone near the sea in winter and summer while in spring and autumn the animals were widespread along the supralittoral. Reproduction occurred from February to November. The minimum average CL at the moment of recovery ranged from 0.22 to 0.28 mm. The sex ratio was female biased. The females and males became distinguishable at 0.35 mm (corresponding to 4.5 mm of LT). The first time that females were observed ovigerous happened when they reached a size about 0.4 mm of CL. The males of T. deshayesii grew larger than the females. The males reached a maximum CL of 1.05 (corresponding to 13.2 mm of LT), while females reached a CL of 1 mm (corresponding to 12.6 mm of LT). Mean length was the lowest in the summer months. Maximum total length was 10.5 mm and the size at first reproduction for the females was 3.5 mm total length. T. deshayesii produced two generations per year. Fecundity varied from 3 to 20 eggs per female and mean fecundity varied through time.