1,721,021 research outputs found
Ingestion and elimination of anthropogenic fibres and microplastic fragments by the European anchovy (Engraulis encrasicolus) of the NW Mediterranean Sea
No full textThis study analysed the anthropogenic microparticles in the stomach content of the European anchovy (Engraulis encrasicolus) in the Ligurian Sea (NW Mediterranean). The results showed that 30-40% of the anchovies had ingested anthropogenic microparticles (on average, 0.34±0.29 fibres ind-1 and 0.12±0.12 fragments ind-1). The fibres were probably ingested via filtration, and were significantly correlated with the gut fullness. Fibres were mostly dark, but the presence of other colours was frequent, indicating a general lack of selectivity. Plastic fragments composed of polyethylene and polypropylene, were prevalently transparent, suggesting active predation, especially for larger fragments resembling zooplankton. No significant differences were recorded for the frequency of fish containing particles among females, males and undetermined individuals. The presence of, generally, only one anthropogenic item per fish, as observed for 95.8% of fish containing microparticles, indicated that the permanence of these particles in the stomachs was short, likely no more than one day, although it could also depend on low environmental concentrations. The evaluation of the intestinal lumen indicated that a portion of the plastic fragments found in the stomach could not be ejected. Hard fragments that were larger than the intestinal lumen could be held for longer times, but probably regurgitation, fragmentation and embedding in a biological matrix may facilitate their quick elimination. It is pivotal to understand the processes that regulate the abundance and the residential time of anthropogenic particles in commercial organisms captured for human nutrition, given the potential biomagnification of toxic substances carried by ingested particles
Zooplankton in the surrounding waters of the Juan Fernández Archipelago
No full textA study for the knowledge of the larval stages of Jasus frontalis (Milne-Edwards, 1836) was used to estimate the qualitative and quantitative structure of zooplankton in the waters of the archipelago Juan Fernandez
Atacama Trench International Expedition
No full textAlthough it has been recognized recently that deep-sea areas might be characterised by benthic “hot-spots”, research on trenches has so far recognized the oligotrophy of these environments both in terms of available food sources and density of benthic organisms. In September 1997, an international expedition promoted by the Istituto di Scienze Ambientali Marine of the University of Genova, involving European and Chilean institutions and with the cooperation of the Servicio Hydrográfico y Oceanográfico de la Armada de Chile, was carried out on board the vessel Vidal Gormaz to study the benthic ecology of the Atacama Trench, which, due to the extremely high productivity of the area, could present special characteristics
Parametri ambientali in Mar Ligure e densità di uova di Engraulis encrasicolus (1985-1996)
No full textThe allochthonous material input in the trophodynamic system of the shelf sediments of the Gulf of Tigullio (Ligurian Sea, NW Mediterranean)
No full textThe organic allochthonous material input in the benthic system of a NW Mediterranean shelf area was studied using a three-pronged approach, focusing firstly on the evaluation of the sedimentary stable isotope ratios and organic matter (OM) composition, then on the OM recycling processes performed by the microbial organisms, and finally on the potential trophic relationships between the macrobenthic organisms. The highest allochthonous signal, indicating continental input, was observed within the 50-m isobath, while at the 80-m isobath the marine signal was higher, pointing to a rather low continental influence approximately 5 km from the shore. Heavier rainfall, often generating abrupt allochthonous inputs by river outfalls, led to a wider spread of fine sediment particles. Carbohydrates were the compounds that best represented the continental input and these compounds were associated with potential recycling activities by microbiota, pointing to the entry of these C-containing allochthonous materials into the microbial food web. The macrofaunal deposit-feeders used sedimentary OM characterised by a continental signature as a food source, although the isotopic ratios of the organisms also pointed to selective feeding on materials that had a marine signature, especially at our offshore sampling stations. Predators fed on deposit- or suspension-feeders, with a potential selection of the latter during the highest inputs of continental materials occurring in winter
Stock assessment of the European anchovy (Engraulis encrasicolus) via DEPM: a non-parametric application to the Ligurian Sea stock
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