Уточнить поиск
Результаты 541-550 из 3,207
Effects of subchronic exposure to glyphosate in juvenile oysters (Crassostrea gigas): From molecular to individual levels Полный текст
2015
Mottier, Antoine | Séguin, Alexis | Devos, Alexandre | Pabic, Charles Le | Voiseux, Claire | Lebel, Jean Marc | Serpentini, Antoine | Fievet, Bruno | Costil, Katherine
Glyphosate-based herbicides are extensively used and can be measured in aquatic ecosystems, including coastal waters. The effect of glyphosate on non-target organisms is an issue of worldwide concern. The aim of this study was to investigate the effects of subchronic exposure to glyphosate in juvenile oysters, Crassostrea gigas. Yearling oysters were exposed to three concentrations of glyphosate (0.1, 1 and 100μgL−1) for 56days. Various endpoints were studied, from the individual level (e.g., gametogenesis and tissue alterations) to the molecular level (mRNA quantification), including biochemical endpoints such as glutathione-S-transferase (GST) and catalase activities and malondialdehyde content. No mortality and growth occurred during the experiment, and individual biomarkers revealed only slight effects. The levels of gene expression significantly increased in oysters exposed to the highest glyphosate concentration (GST and metallothioneins) or to all concentrations (multi-xenobiotic resistance). These results suggested an activation of defence mechanisms at the molecular level.
Показать больше [+] Меньше [-]Levels, spatial variation and compartmentalization of trace elements in brown algae Cystoseira from marine protected areas of Crimea (Black Sea) Полный текст
2015
Kravtsova, Alexandra V. | Milchakova, Nataliya A. | Frontasyeva, Marina V.
Levels of Al, Sc, V, Co, Ni, As, Br, Rb, Sr, Ag, Sb, I, Cs, Ba, Th and U that were rarely or never studied, as well as the concentrations of classically investigated Mn, Fe and Zn in brown algae Cystoseira barbata C. Ag. and Cystoseira crinita (Desf.) Bory from the coastal waters of marine protected areas (Crimea, Black Sea), were determined using neutron activation analysis. Spatial variation and compartmentalization were studied for all 19 trace elements (TE). Concentrations of most TE were higher in “branches” than in “stems”. Spatial variations of V, Co, Ni and Zn can be related to anthropogenic activities while Al, Sc, Fe, Rb, Cs, Th and U varied depending on chemical peculiarities of the coastal zone rocks. TE concentrations in C. crinita from marine protected areas near Tarkhankut peninsula and Cape Fiolent, identified as the most clean water areas, are submitted as the background concentrations.
Показать больше [+] Меньше [-]Response of microbial communities to bioturbation by artificially introducing macrobenthos to mudflat sediments for in situ bioremediation in a typical semi-enclosed bay, southeast China Полный текст
2015
Ma, Ying | Hu, Anyi | Yu, Chang-Ping | Yan, Qingpi | Yan, Xizhu | Wang, Yongzhong | Deng, Fei | Xiong, Hejian
Although microbes play important roles during the bioremediation process using macrobenthos in degraded environments, their response to macrobenthos bioturbation remains poorly understood. This study used 16S rRNA gene-Illumina Miseq sequencing to investigate the microbial communities and their response to bioturbation by artificially introducing macrobenthos to the mudflat of Sansha Bay, southeast China. A total of 56 phyla were identified, dominated by δ- and γ-Proteobacteria, with a total percentage of over 50%. Others, such as Acidobacteria, Chloroflexi, Bacteroidetes, Planctomycetes and Alphaproteobacteria occupied 4–7% respectively. Eighteen genera indicating the microbial communities response to bioturbation and seasonal change were identified. Bioturbated samples contained more ecologically important genera, and untreated samples contained more genera ubiquitous in marine environments. The physicochemical characteristics did not change significantly probably due to the short time of bioremediation and low survival rate of macrobenthos, confirming that microbial communities are more sensitive and can serve as sentinels for environmental changes.
Показать больше [+] Меньше [-]Plastic in surface waters of the Inside Passage and beaches of the Salish Sea in Washington State Полный текст
2015
Davis, Wallace | Murphy, Anne G.
We summarize results of two independent studies on plastic pollution in the marine environment that overlap in time and space. One study evaluated the abundance of anthropogenic debris on 37 sandy beaches bordering the Salish Sea in Washington State while the other characterized plastic debris in surface waters of the Salish Sea and the Inside Passage to Skagway, Alaska. Both studies concluded that foam, primarily expanded polystyrene was the dominant pollutant. Plastic was found in surface waters the full length of the Inside Passage but was concentrated near harbors. At the wrack line, an average square meter of Washington’s 1180km of sandy beaches in the Salish Sea had 61 pieces of anthropogenic debris weighing approximately 5g. The total loading for the entire 1m wide band is estimated to be 72,000,000 pieces and 5.8metric tons. Most anthropogenic debris on beaches is generated within the region.
Показать больше [+] Меньше [-]Tracking the origins of plastic debris across the Coral Sea: A case study from the Ouvéa Island, New Caledonia Полный текст
2015
Maes, Christophe | Blanke, Bruno
Tracking the origins of plastic debris across the Coral Sea: A case study from the Ouvéa Island, New Caledonia Полный текст
2015
Maes, Christophe | Blanke, Bruno
Contamination of the marine environment by human-made plastic litter is a growing and global problem. Our study attempts to explain the presence of two plastic bottles beached on the Ouvéa Island, in the southwest Pacific Ocean, with trademarks from the Solomon Islands and Papua New Guinea (PNG). We simulate the oceanic drift tracks and associated transit times with a Lagrangian interpretation of the surface currents of a high-resolution ocean model. Our results show that it takes less than 2–3months for drifting objects to connect these archipelagos (New Caledonia, Solomon Islands and PNG) and highlight the role of the meridional component of the circulation rather than the dominant zonal jets. This study shows that the origin or traceability of trash represent valuable information that can be used to test and, ultimately, improve our understanding of ocean circulation.
Показать больше [+] Меньше [-]Tracking the origins of plastic debris across the Coral Sea: A case study from the Ouvéa Island, New Caledonia Полный текст
2015
Maes, Christophe | Blanke, Bruno
Contamination of the marine environment by human-made plastic litter is a growing and global problem. Our study attempts to explain the presence of two plastic bottles beached on the Ouvéa Island, in the southwest Pacific Ocean, with trademarks from the Solomon Islands and Papua New Guinea (PNG). We simulate the oceanic drift tracks and associated transit times with a Lagrangian interpretation of the surface currents of a high-resolution ocean model. Our results show that it takes less than 2–3 months for drifting objects to connect these archipelagos (New Caledonia, Solomon Islands and PNG) and highlight the role of the meridional component of the circulation rather than the dominant zonal jets. This study shows that the origin or traceability of trash represent valuable information that can be used to test and, ultimately, improve our understanding of ocean circulation.
Показать больше [+] Меньше [-]Impact of cigarette butt leachate on tidepool snails Полный текст
2015
Booth, David J. | Gribben, Paul | Parkinson, Kerryn
In urban areas, cigarette butts are the most common discarded refuse articles. In marine intertidal zones, they often fall into tidepools. We tested how common intertidal molluscs were affected by butt leachate in a laboratory experiment, where snails were exposed to various leachate concentrations. Mortality was very high, with all species showing 100% mortality at the full leachate concentration (5 butts per litre and 2h soak time) after 8days. However, Austrocochlea porcata showed higher mortality than the other 2 species at lower concentrations (10%, 25%) which may affect the relative abundance of the 3 snails under different concentrations of leachate pollution. Also, sublethal effects of leachate on snail activity were observed, with greater activity of Nerita atramentosa than the other 2 species at higher concentrations, suggesting it is more resilient than the other 2 species.While human health concerns predominate with respect to smoking, we show strong lethal and sublethal (via behavioural modifications) impacts of discarded butts on intertidal organisms, with even closely-related taxa responding differently.
Показать больше [+] Меньше [-]Modelling the transport and accumulation of floating marine debris in the Mediterranean basin Полный текст
2015
Mansui, J. | Molcard, A. | Ourmières, Y.
In the era of plastic and global environmental issues, when large garbage patches have been observed in the main oceanic basins, this work is the first attempt to explore the possibility that similar permanent accumulation structures may exist in the Mediterranean Sea. The questions addressed in this work are: can the general circulation, with its sub-basins scale gyres and mesoscale instabilities, foster the concentration of floating items in some regions? Where are the more likely coastal zones impacted from open ocean sources?Multi-annual simulations of advected surface passive debris depict the Tyrrhenian Sea, the north-western Mediterranean sub-basin and the Gulf of Sirte as possible retention areas. The western Mediterranean coasts present very low coastal impact, while the coastal strip from Tunisia to Syria appears as the favourite destination. No permanent structure able to retain floating items in the long-term were found, as the basin circulation variability brings sufficient anomalies.
Показать больше [+] Меньше [-]Polluter identification with spaceborne radar imagery, AIS and forward drift modeling Полный текст
2015
Longépé, N. | Mouche, A.A. | Goacolou, M. | Granier, N. | Carrère, L. | Lebras, J.Y. | Lozach, P. | Besnard, S.
This study defines and assesses a new operational concept to identify the origin of pollution at sea, based on Synthetic Aperture Radar, Automatic Identification System, and a forward drift model. As opposed to traditional methodologies where the SAR detected pollution is backtracked in the past, our approach assumes that all the vessels pollute all along their way. Based on all the AIS data flows, the forward-tracked simulated pollutions are then compared to the detected pollution, and the potential polluter can be finally identified. Case studies are presented to showcase its usefulness in a variety of maritime situations with a focus on orphan pollutions in a dense traffic area. Out of the identification of the suspected polluters, the age and eventually the type of the pollution can be retrieved.
Показать больше [+] Меньше [-]Investigation of polycyclic aromatic hydrocarbons (PAHs) and cyclic terpenoid biomarkers in the sediments of fishing harbors in Taiwan Полный текст
2015
Kao, Nien-Hsin | Su, Ming-Chien | Fan, Jheng-Rong | Yen, Chih-Chun
Three fishing harbors were investigated to study the polycyclic aromatic hydrocarbons in the sediments and trace possible anthropogenic sources by identification of cyclic terpenoid biomarkers. Seventeen terpanes, 10 steranes and 10 bicyclic sesquiterpanes in the marine diesel and the three kinds of lubricants that are mainly used by fishing boats were identified and quantified. Eighteen biomarker diagnostic ratios are suggested and the correlation coefficients among the lubricants and sediment samples have the R2 value greater than 0.73. Analyzed 16 PAHs in the sediment shows non-normal distributions and the Kruskal Wallis Test shows the significant differences (p value smaller than 0.05) with the greatest variability in benzo[g,h,i]perylene which more than 84% of the effective size (E.S.) is accounted. X-ray Photoelectron Spectroscopy (XPS) analysis was applied and the Kruskal Wallis Test shows a significant difference (p value smaller than 0.05) among certain atoms with the effective size greater than 60%.
Показать больше [+] Меньше [-]Mediterranean marine biodiversity under threat: Reviewing influence of marine litter on species Полный текст
2015
Deudero, Salud | Alomar, Carme
The Mediterranean Sea is one of the most polluted seas worldwide, especially with regard to plastics. The presence of this emerging man made contaminant in marine environments precludes large effects and interactions with species exposed to massive litter quantities. In this review, available data of floating and seafloor litter around Mediterranean sub-basins are reported. A review of scientific literature on the interaction of plastic with marine biota resulted in the identification of 134 species, several taxa and feeding strategies affected from 1986 to 2014. Data from 17,334 individuals showed different levels of ingestion and effects on catalogued IUCN species (marine mammals and sea turtles) in addition to several pelagic fish and elasmobranchs. Biodiversity is certainly under threat, and knowledge of the extent of taxa affected is of concern considering the increasing plastic loads in the Mediterranean Sea and worldwide.
Показать больше [+] Меньше [-]