1,720,958 research outputs found
EVALUATION OF EFFECTS OF NEW ANTIFOULING SYSTEMS, ALTERNATIVE TO ORGANOTIN COMPOUNDS, ON BENTHIC MARINE INVERTEBRATES AT ECOSYSTEM, ORGANISMAL AND CELLULAR LEVEL
Full text linkMarine biofouling on anthropic submerged substrata is associated with major ecological and socioeconomic impacts worldwide. The most widely used antifouling systems are chemical ones represented by paints with a biocide, to which booster substances can be added. The latter are highly toxic chemical substances from agriculture (herbicides, fungicides, acaricides, wood preservatives) and pharmaceutical industry (bactericides, fungicides), these cause various ecological problems due to disruptive effects provoked on non-target organisms and depletion of coastal biocoenoses. From 2001, the paints including organotin compounds (TBT and TPT), which had the best performance and were used worldwide for decades, were banned by International Maritime Organization (IMO) after the discovery of their severe impact on the oyster farms. As a consequence of the restrictions on the use of organotin-based paints, finding new antifouling systems has become a primary necessity. Therefore, the research was devoted to new eco-friendly formulations. Regarding Physical antifouling systems have been recently introduced in relation to the development of a more environmentally friendly approach rather than the chemical systems.
My scholarship has been entirely financed by RESIMIX s.r.l of Brendola, Vicenza (Italy). The university-enterprise collaboration aimed to develop a new eco-friendly paint. More in general, the research program of my PhD thesis focused on the implementation of new antifouling systems with low effects on benthic marine invertebrates. My PhD activity it was been divided in 2 tasks, i.e., chemical antifouling systems and physical antifouling systems. To determine and compare the effects of these new antifouling systems on both target species (ascidians and mussels) and non-target species (clams) the tasks have been developed at three study levels, i.e., ecosystem, individuals, and cells.
As regards of chemical antifouling systems I have been investigated the significant differences in the ecological succession of hard-substratum community, by means of a series of biodiversity indexes, during at least one-year exposure to various RESIMIX paints and trade copper-based paints. In addition, a comparative monitoring with trade antifouling paints has been considered together with the effects on settlement and metamorphosis of ascidian larvae and finally, the observation of the mechanisms of action in in vitro immunotoxicity assays on dominant bioindicators in benthic biocoenoses like tunicates, clams and mussels. From these preliminary but significant results about chemical antifouling systems, crucial questions have arisen regarding the continuous indiscriminate introduction of such biocides into the environment.
As regards physical antifouling systems I have been considered geotextiles (for protection from coastal erosion), and ultrasound (to prevent biofilm and disturb the larval settlement) reaching interesting results in both the field and the lab, which revealed the till now hidden downside of these systems.Marine biofouling on anthropic submerged substrata is associated with major ecological and socioeconomic impacts worldwide. The most widely used antifouling systems are chemical ones represented by paints with a biocide, to which booster substances can be added. The latter are highly toxic chemical substances from agriculture (herbicides, fungicides, acaricides, wood preservatives) and pharmaceutical industry (bactericides, fungicides), these cause various ecological problems due to disruptive effects provoked on non-target organisms and depletion of coastal biocoenoses. From 2001, the paints including organotin compounds (TBT and TPT), which had the best performance and were used worldwide for decades, were banned by International Maritime Organization (IMO) after the discovery of their severe impact on the oyster farms. As a consequence of the restrictions on the use of organotin-based paints, finding new antifouling systems has become a primary necessity. Therefore, the research was devoted to new eco-friendly formulations. Regarding Physical antifouling systems have been recently introduced in relation to the development of a more environmentally friendly approach rather than the chemical systems.
My scholarship has been entirely financed by RESIMIX s.r.l of Brendola, Vicenza (Italy). The university-enterprise collaboration aimed to develop a new eco-friendly paint. More in general, the research program of my PhD thesis focused on the implementation of new antifouling systems with low effects on benthic marine invertebrates. My PhD activity it was been divided in 2 tasks, i.e., chemical antifouling systems and physical antifouling systems. To determine and compare the effects of these new antifouling systems on both target species (ascidians and mussels) and non-target species (clams) the tasks have been developed at three study levels, i.e., ecosystem, individuals, and cells.
As regards of chemical antifouling systems I have been investigated the significant differences in the ecological succession of hard-substratum community, by means of a series of biodiversity indexes, during at least one-year exposure to various RESIMIX paints and trade copper-based paints. In addition, a comparative monitoring with trade antifouling paints has been considered together with the effects on settlement and metamorphosis of ascidian larvae and finally, the observation of the mechanisms of action in in vitro immunotoxicity assays on dominant bioindicators in benthic biocoenoses like tunicates, clams and mussels. From these preliminary but significant results about chemical antifouling systems, crucial questions have arisen regarding the continuous indiscriminate introduction of such biocides into the environment.
As regards physical antifouling systems I have been considered geotextiles (for protection from coastal erosion), and ultrasound (to prevent biofilm and disturb the larval settlement) reaching interesting results in both the field and the lab, which revealed the till now hidden downside of these systems
Effects of geotextiles for coastal erosion control on marine fouling settlement.
No full textIn recent years, the prevention of coastal erosion has arisen as a top priority for reducing the damage to structures and loss of lands. Climatic change is making the erosion rates worse by increasing in storm frequency and intensity. The high coastline recession rates cause significant concern in heavily populated locations. New tools are represented by nonwoven geotextiles. They are made of polypropylene (PP) and polyester (PET) fibres, which are useful in artificial structures for coastal protection. On the other hand, they represent an alternative to natural hard substrates and could interfere with the settlement of fouling species in respect of natural substrates. To better understand the effects of geotextiles on the colonisation capability of macrofouling organisms, a 10-months study was carried out in the Lagoon of Venice (Italy).Three different needle-punched staple fibre geotextiles were chosen: 1) White-PP, 2) hot-calendered White PP&PET, and 3) multi-layered Coloured PP&PET. Fouling settlement was monitored and analysed on panels replaced monthly with the aim to investigate significant differences among the covering surfaces of each fouling species. The measures of the areas (cm2) per month were compared using PERMANOVA considering two fixed factors, i.e., geotextiles and month.
All geotextiles revealed a negative effect on the settlement of green and red algae, bivalve molluscs and barnacles. Conversely, they showed a positive selective effect towards both solitary and colonial ascidians. As regards the 18 organisms observed, PERMANOVA showed that for four of the organisms (Ulva rigida, Ceramium ciliatum, Janua heterostropha, Bugula neritina) the settlement takes place according to a significant negative selection on basis of both fixed parameters considered in the analysis (month and geotextile). Conversely, for two tunicates (Ciona robusta and
Diplosoma listerianum) the positive selection on settlement capacity appears to be significantly dependent only according to month and not to the type of geotextiles.
Therefore, it must be considered that a long-term and extensive use of geotextiles worldwide could negatively affect local biodiversity and community growth on coasts. The progressive loss of pivot species in favour of the selection of dominant and/or invasive species could trigger negative consequences in both trophic chains of coastal ecosystems and in economical relevant activities of fishing industry and aquaculture
Selective potential of geotextiles on marine fouling settlement
Full text linkIn recent years, the prevention of coastal erosion due to the action of waves, currents, tides and organisms has arisen as a top priority for reducing the damage to structures and loss of lands. Climatic change is making the erosion rates worse by increasing in storm frequency and intensity. The high coastline recession rates cause significant concern in heavily populated locations. New tools for application in hydraulic engineering are represented by nonwoven geotextiles. These materials are made of polypropylene (PP) and polyester (PET) fibres, have physical and hydraulic properties, which are useful in artificial structures for coastal protection as an alternative to natural hard substrates. On the other hand, they could interfere with the settlement of fouling species in respect of natural substrates. To better understand the potential effects of geotextiles on the colonization capability of fouling organisms, a 10-months study was carried out in the Lagoon of Venice (Italy), a particular environment of temperate transitional waters with high biodiversity. Three different needle punched staple fibre
geotextiles were chosen from Naue GmbH & Co. (Germany): 1) Secutex R601 (white PP), 2) Secutex 251 GRK 4C (hot-calendered white PP and PET), and 3) Terrafix B 609 (multi-layered coloured PP and white PET). Fouling settlement was monitored and analysed on panels replaced monthly and compared with the colonization on wood panels as a reference substrate. All geotextiles revealed a negative effect on the settlement of green and red algae, bivalve molluscs and barnacles. Secutex R601 and Terrafix B 609 also inhibited the settlement of serpulids. Conversely, they showed a positive selective effect towards various ascidian species. The loss of pivot species in favour of the selection of dominant and/or invasive species could trigger negative consequences in both trophic chains of coastal ecosystems and in economical relevant activities of fishing industry and aquaculture
Two facets of geotextiles in coastal ecosystems: Anti- or profouling effects?
Full text linkNonwoven geotextile fabrics have physical, mechanical and hydraulic properties useful in coastal protection as an alternative to natural stone, slag, and concrete. In a 10-month experiment, the colonisation of macrofouling organisms on different substrata based on polypropylene (PP), polyester (PET) or high density polyethylene (HDPE) fibres was investigated in the Lagoon of Venice, Italy – an environment with temperate transitional waters with high biodiversity – and compared with the colonisation on wood as a reference substratum, because of its occurrence in artificial structures at the study location, until a stable stage was reached in the development of the macrofouling community. Geotextile fabrics showed implications for community development. They affected both ecological succession in different ways by disturbing biofouling settlement and growth (HDPE fabrics) or favouring species which become dominant (PP fabrics). For these two-faceted aspects that potentially cause different long-term impacts on the biodiversity of resident communities, the use of geotextile fabrics as
antifouling or as profouling systems for restoration of degraded ecosystems is discussed. In all cases, the communities displayed unique properties, such as differences in the settlement of pioneer species, an initial disturbance to serpulid settlement, absence of barnacles, selection of dominant taxa (ascidians), and changes in the percentages of various taxa forming the community structure. Given the increasing interest in geotextile materials for employment in various marine developments and industries, these results could represent first lines of evidence to inform decision-making to minimise/modify biofouling, and/or predict the use of artificial substrata as habitats by marine organisms
Potential disruptive effects of copper-based antifouling paints on biodiversity of coastal macrofouling community.
No full textIn recent years, after the ban on tributyltin (TBT)-based antifouling paints, copper-based paints have become the main coatings for boat hulls due to their effectiveness, efficiency and endurance. Copper(I) compounds are used alone or in combination with booster biocides. The expanded use of these paints has increased copper leaching into coastal environments, requiring attention and legislative restrictions. This study monitored the ecological succession of macrofouling communities on wooden and steel panels immersed for 10 months in the southern basin of the Lagoon of Venice. The development of macrofouling communities on the panels coated with copper-containing antifouling paints was compared with those on the reference (uncoated) and TBT-coated panels. To describe the effects on the communities, PERMANOVA and a series of biodiversity descriptors were considered; these descriptors highlighted the disturbing activity of the antifouling paints that resulted in negative species selection
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
An exploratory analysis of bromine compounds and pyrethroids in stranded sperm whales
No full textSulle coste italiane del mar Adriatico a Vasto (Abruzzo, Italia) il 12 settembre 2014 sono deceduti, in seguito ad uno spiaggiamento, tre esemplari di capodoglio (Physeter macrocephalus).
In seguito all’evento sono stati raccolti campioni destinati a varie analisi. Per questo elaborato ci si è concentrati sulle analisi tossicologiche e i campioni analizzati sono stati: blubber, cervello, cuore, muscolo, fegato, feci e cordone ombelicale. Su questi campioni sono state indagate le concentrazioni tissutali di Ritardanti di fiamma e Piretroidi.
Lo scopo di questa ricerca è mirato alla valutazione del potenziale ruolo patogenetico di questi inquinanti che agiscono su numerosi distretti organici, sul sistema immunitario ed endocrino, al fine di cercare di comprendere, attraverso la letteratura esistente, l’interpretazione dei dati ottenuti e la formulazione d’ipotesi, se l’esposizione a tali inquinanti possa influenzare in modo diretto o indiretto lo spiaggiamento di questa specie e se c’è una relazione di traferimento materno-fetale di tali composti (dato che uno degli individui era incinta). Sono stati trovati valori di ritardanti di fiamma anche nei campioni fetali, questo porta ad ipotizzare il trasferimento placentare dei contaminanti. Questo particolare è importante e contribuisce ad arricchire enormemente le nozioni disponibili sul comportamento, l’accumulo e l’escrezione di questi contaminanti nei cetacei. Nonostante la letteratura e i risultati da noi ottenuti individuino come organo target per lo studio dei ritardanti di fiamma il blubber, e per i piretroidi il muscolo, questo studio dimostra la presenza di tali contaminanti anche in altri distretti anatomici dell’organismo dei capodogli. Lo scopo, quindi, di questo studio è di ottenere informazioni più estese ed approfondite sullo stato di inquinamento del Mediterraneo, sulla tossicocinetica delle sostanze in esame e sui possibili effetti nocivi che potrebbero affliggere del capodoglio
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