1,721,040 research outputs found
Light and shade in marine conservation across European and contiguous seas
No full textAs a response to increasing human pressures on marine ecosystems, the legislation aimed at improving the conservation and management of marine coastal areas in European and Contiguous Seas (ECS) underwent crucial advances. ECS, however, still remain largely affected by increasing threats leading to biodiversity loss. Here, by using emblematic case studies and expert knowledge, we review current conservation tools, comparing their application in different areas to assess their effectiveness, potential for synergies, and contradictions. Despite regional differences in their application, the existing legislative frameworks have the potential to regulate human activities and to protect marine biodiversity. However, four challenges remain to be addressed to fully achieve environmental policy goals: (1) Lack of shared vision representing a limitation in transboundary collaboration. Although all EU countries are committed to fulfil EU Directives and other binding international legislative acts, a remarkable heterogeneity exists among countries in the compliance with the common legislation on conservation and in their degree of implementation. (2) Lack of systematic procedures for the selection of protected marine sites. Regional and national approaches in designating Natura 2000 sites and nationally designated marine protected areas (MPAs) reflect varying conservation targets and importance of conservation issues in political agendas. (3) Lack of coherent ecological networks. Natura 2000 sites and other MPAs are still far from reaching the status of effective networks in all considered case studies. (4) Hotspot of conflicts with private economic interests prevailing over conservation aims. Recommendations are given to overcome the fragmented approach still characterizing the conservation and management of coastal marine environments. Holistic, integrated, ecosystem-based, cross-cutting approaches can avoid conflicts among institutions so as to provide effective and timely solutions to current and future challenges concerning the conservation and management of marine ecosystems and associated goods and services. © 2018 Fraschetti,
Effects of PVP/PEI coated and uncoated silver NPs and PVP/PEI coating agent on three species of marine microalgae
No full textIn the last years, applications for silver nanoparticles (Ag NPs) continue to increase together with the concerns about their potential input and hazards in aquatic ecosystems, where microalgae are key organisms. The aim of the present study was to assess the relative sensitivity of three marine microalgae species with differences in cell wall composition/structure exposed to Poly N-vinyl-2-pirrolidone/Polyethyleneimine (PVP/PEI) coated 5 nm Ag NPs and uncoated 47 nm Ag NP. As limited attention has been paid to the role of coating agents in NP toxicity, the effect of PVP/PEI alone was also evaluated. After 72 h in artificial seawater, 47 nm Ag NPs formed around 1400 nm size aggregates while PVP/PEI coated 5 nm Ag NPs reached around 90 nm. Ag+ release in seawater was around 3% for 47 nm Ag NPs and 30% for PVP/PEI coated 5 nm Ag NPs. PVP/PEI coated 5 nm Ag NP aggregates entrapped the algal cells in a network of heteroaggregates, while uncoated 47 nm Ag NPs interacted to a lesser extent with algae. The concentration of PVP/PEI coated 5 nm Ag NPs that exerted the median effect (EC50) on algae growth pointed out differences in algae sensitivity: T. suecica was about 10 times more sensitive than I. galbana and P. tricornutum. Further, the coating agent alone was as toxic to algae as PVP/PEI coated 5 nm Ag NPs, suggesting that presence of the coating agent was the main driver of toxicity of coated NPs. Uncoated 47 nm Ag NPs instead, showed similar toxicity towards algae although P. tricornutum was slightly less sensitive than T. suecica and I. galbana, which agrees with the presence of a resistant silicified cell wall in the diatom. The present work demonstrates differences in sensitivity of three marine microalgae, possibly related to their cell surface and size characteristics. © 2016 Elsevier B.V
Immune and reproductive system impairment in adult sea urchin exposed to nanosized ZnO via food
No full textIn marine environment the release and the consequent sedimentation of ZnO NPs, mainly used in sunscreens, could provoke toxic effects in particular in grazer organisms, like sea urchins. In this work, a first evaluation of DNA and cellular effects on adult sea urchins Paracentrotus lividus exposed through the diet to different sizes (100 and 14 nm) ZnO NPs, was performed. Moreover, the consequent impact upon offspring quality was evaluated. Preliminarily results showed that the assumption of food containing ZnO NPs 100 nm provoked in adult echinoids damages to immune cells (33% of damaged nucleus) and transmissible effects to offspring (75.5% of malformed larvae). Instead food with ZnO NPs 14 nm provoked 64% of damaged nucleus in immune cells and 84.7% of malformed larvae. © 2017 Elsevier B.V
Application of a toxicity test battery integrated index for a first screening of the ecotoxicological threat posed by ports and harbors in the southern Adriatic Sea (Italy)
No full textPorts and harbors may represent a threat for coastal ecosystems due to pollutant inputs, especially those derived from maritime activities. In this study, we report a first assessment of the ecotoxicological threat posed by six ports and harbors of opposite coastal regions, Apulia and Albania, in the southern Adriatic Sea (Italy). A bioassay battery consisting of four different species representing different trophic levels, algae Dunaliella tertiolecta, bacteria Vibrio fischeri, crustacean Artemia salina, and echinoids Paracentrotus lividus, has been used to assess sediment elutriates, pore waters, and sediment suspensions. Two different approaches of toxicity data integration, worst case and integrated index, have been used to determine the most appropriate procedure for the investigated sites. All sites with the worst case approach showed high toxicity levels. The chronic test with algae was the most sensitive identifying the highest effects in the battery. This effect can be attributable to contaminants derived from antifouling paints. The sediments, evaluated with V. fischeri test, often showed toxicity not found in the aqueous matrices of the same sites and that can be mainly linked to organic compounds. The test battery used in this study allowed us to perform a preliminary screening of the ecotoxicological risk of the studied area. In fact, the species utilized for toxicity tests responded differently to the investigated samples, showing different sensitivity. The test battery integrated index did not allow highlighting the differences among the sites and showed a general high ecotoxicological risk. A larger number of tests with higher sensitivity together with a tailored attribution of weights to endpoints and matrices will improve the final site evaluation
Physical and chemical threats posed by micro(nano)plastic to sea urchins
No full textThe awareness of the plastic issue is rising in recent years. Our seas and coastal seawaters are investigated with the aim to evaluate the possible fate, behavior and the impact of these novel contaminants upon marine biota. In particular, benthic organisms are exposed to micro(nano)plastics that sink and accumulated on the seabed. Sea urchins can be prone to the plastic impact for all their lifespan with effect that can be extended upon the trophic cascade since their key role as grazer organisms. Moreover, they are largely used in the assessment of contaminant impact both as adult individuals and as early larval stages. This review analyzes the recent literature about the chemical and physical hazards posed by diverse polymers to sea urchins, in relation to their peculiar characteristics and to their size. The search was based on a query of the keyword terms: microplastic _ OR nanoplastic_AND Sea urchins in Web of Science and Google Scholar. The effects provoked by exposure of different sea urchin biological form are highlighted, considering both laboratory exposure and collection in real world. Additional focus has also been given upon the exposure methods utilized in laboratory test and in the existing limitations in the testing procedures. In conclusion, the micro(nano)plastics major impact seemed to be attributable to leaching compounds, however variability and lacking of realisms in the procedures do not allow a full understanding of the hazard posed by micro(nano)plastics for sea urchins. Finally, the work provides insights into the future research strategies to better characterize the actual risk for sea urchins
Nanoparticles based sunscreens provoke adverse effects on marine microalgae Dunaliella tertiolecta
No full textSunscreens represent one of the main sources of engineered TiO2 and ZnO nanoparticles (NPs) in coastal ecosystems, especially during the summer period. To understand the effective environmental impact of NPs in commercial sunscreens, this study assesses the effect of TiO2 and ZnO NPs extracted from three commercial products (S2; S10; S11) upon marine microalgae Dunaliella tertiolecta by evaluating its growth inhibition, oxidative stress and DNA damage. Algae were exposed to both the sunscreen formulations containing NPs and a sunscreen without NPs. Results showed that algae growth inhibition was affected by the extracted NPs (EC20 S2: 9.2 mg Ti L−1; EC20 S10: 0.49 mg Ti L−1; EC20 S11: 14 mg Ti L−1), and the algae was generally biostimulated by the sunscreen formulations, due to the presence of other components that could enhance algal growth. Among the sunscreens containing NPs, relevant effects, mainly as ROS production and DNA damage, were evidenced when both TiO2 and Zn were present (S10; S11). Moreover, lower effects were always observed for the sunscreens and the corresponding extracts, compared to the effects of industrial NPs. These findings suggest that the product formulation may mitigate toxic effects of NPs either by direct modification of properties or by providing organic and inorganic nutrients that biostimulate microalgae growth. The NPs extracted from sunscreens showed responses that cannot be predicted solely from the response of industrial nanoparticles, suggesting that the aging in sunscreens can influence the final toxicity of nanoparticles. In conclusion, the adverse effects of sunscreens upon microalgae could not be solely attributed to the NPs, but also to the combined action of multiple components. © The Royal Society of Chemistry
Genotoxic and cytotoxic effects of ZnO nanoparticles for Dunaliella tertiolecta and comparison with SiO2 and TiO2 effects at population growth inhibition levels
No full textThe increasing use of oxide nanoparticles (NPs) in commercial products has intensified the potential release into the aquatic environment where algae represent the basis of the trophic chain. NP effects upon algae population growth were indeed already reported in literature, but the concurrent effects at cellular and genomic levels are still largely unexplored.Our work investigates the genotoxic (by COMET assay) and cytotoxic effects (by qualitative ROS production and cell viability) of ZnO nanoparticles toward marine microalgae Dunaliella tertiolecta. A comparison at defined population growth inhibition levels (i.e. 50% Effect Concentration, EC50, and No Observed Effect Concentration, NOEC) with SiO2 and TiO2 genotoxic effects and previously investigated cytotoxic effects (Manzo et al., 2015) was performed in order to elucidate the possible diverse mechanisms leading to algae growth inhibition.After 72 h exposure, ZnO particles act firstly at the level of cell division inhibition (EC50: 2 mg Zn/L) while the genotoxic action is evident only starting from 5 mg Zn/L. This outcome could be ascribable mainly to the release of toxic ions from the aggregate of ZnO particle in the proximity of cell membrane.In the main, at EC50 and NOEC values for ZnO NPs showed the lowest cytotoxic and genotoxic effect with respect to TiO2 and SiO2. Based on Mutagenic Index (MI) the rank of toxicity is actually: TiO2 > SiO2 > ZnO with TiO2 and SiO2 that showed similar MI values at both NOEC and EC50 concentrations.The results presented herein suggest that up to TiO2 NOEC (7.5 mg/L), the algae DNA repair mechanism is efficient and the DNA damage does not result in an evident algae population growth inhibition. A similar trend for SiO2, although at lower effect level with respect to TiO2, is observable.The comparison among all the tested nanomaterial toxicity patterns highlighted that the algae population growth inhibition occurred through pathways specific for each NP also related to their different physicochemical behaviors in seawater. © 2016 Elsevier B.V.
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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