Refinar búsqueda
Resultados 1261-1270 de 4,042
Estimation of mercury background values in sediment and biota of the Bijagós archipelago, Guinea-Bissau Texto completo
2016
Coelho, J.P. | Monteiro, R.J.R. | Catry, T. | Lourenço, P.M. | Catry, P. | Regalla, A. | Catry, I. | Figueira, P. | Pereira, E. | Vale, C. | P.Granadeiro, José
Estimation of mercury background values in sediment and biota of the Bijagós archipelago, Guinea-Bissau Texto completo
2016
Coelho, J.P. | Monteiro, R.J.R. | Catry, T. | Lourenço, P.M. | Catry, P. | Regalla, A. | Catry, I. | Figueira, P. | Pereira, E. | Vale, C. | P.Granadeiro, José
This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós archipelago, off the coast of Guinea-Bissau. Sediments exhibited very low concentrations (<1–12ngg−1), pointing to negligible sources of anthropogenic Hg in the region. Nevertheless, Hg is well correlated to the fine fraction, aluminium, and loss on ignition, indicating the effect of grain size and organic matter content on the presence of Hg in sediments. Mercury in the bivalves Tagelus adansoni and Senilia senilis did not vary considerably among sites, ranging within narrow intervals (0.09–0.12 and 0.12–0.14μgg−1 (dry weight), respectively). Divergent substrate preferences/feeding tactics may justify slight differences between species. The value 11ngg−1 is proposed as the sediment background concentration for this West-African coastal region, and concentrations within the interval 8–10ngg−1 (wet weight) may be considered as reference range for S. senilis and T. adansoni in future monitoring studies.
Mostrar más [+] Menos [-]Estimation of mercury background values in sediment and biota of the Bijagós archipelago, Guinea-Bissau Texto completo
2016
Coelho, J. P. | Monteiro, R. J. R. | Catry, Teresa | Lourenço, Pedro Miguel | Catry, Paulo | Regalla, Aissa Said | Catry, Inês | Figueira, Paula | Pereira, Eduarda | Vale, Carlos | Granadeiro, José Pedro
This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós archipelago, off the coast of Guinea-Bissau. Sediments exhibited very low concentrations (<1-12ngg(-1)), pointing to negligible sources of anthropogenic Hg in the region. Nevertheless, Hg is well correlated to the fine fraction, aluminium, and loss on ignition, indicating the effect of grain size and organic matter content on the presence of Hg in sediments. Mercury in the bivalves Tagelus adansoni and Senilia senilis did not vary considerably among sites, ranging within narrow intervals (0.09-0.12 and 0.12-0.14μgg(-1) (dry weight), respectively). Divergent substrate preferences/feeding tactics may justify slight differences between species. The value 11ngg(-1) is proposed as the sediment background concentration for this West-African coastal region, and concentrations within the interval 8-10ngg(-1) (wet weight) may be considered as reference range for S. senilis and T. adansoni in future monitoring studies. | Fundação para a Ciência e a Tecnologia (FCT); MAVA Foundation
Mostrar más [+] Menos [-]A novel biomarker for marine environmental pollution of HSP90 from Mytilus coruscus Texto completo
2016
Liu, Huihui | Wu, Jiong | Xu, Mengshan | He, Jianyu
Heat shock protein 90 (HSP90) is a conserved molecular chaperone contributing to cell cycle control, organism development and the proper regulation of cytosolic proteins. The full-length HSP90 cDNA of Mytilus coruscus (McHSP90, KT946644) was 2420bp, including an ORF of 2169bp encoding a polypeptide of 722 amino acids with predicted pI/MW 4.89/83.22kDa. BLASTp analysis and phylogenetic relationship strongly suggested McHSP90 was a member of HSP90 family, and it was highly conserved with other known HSP90, especially in the HSP90 family signatures, ATP/GTP-Binding sites and ‘EEVD’ motif. The mRNA of McHSP90 in haemolymph was upregulated in all treatments including Vibrio alginolyticus and Vibrio harveyi challenge, metals stresses (copper and cadmium) and 180 CST fuel exposure. All the results implied the expression of McHSP90 could be affected by Vibrio challenge and environmental stress, which might help us gain more insight into the molecular mechanism of HSP against adverse stresses in mollusca.
Mostrar más [+] Menos [-]Microbial colonization and degradation of polyethylene and biodegradable plastic bags in temperate fine-grained organic-rich marine sediments Texto completo
2016
Nauendorf, Alice | Krause, Stephan | Bigalke, Nikolaus K. | Gorb, Elena V. | Gorb, Stanislav | Haeckel, Matthias | Wahl, Martin | Treude, Tina
To date, the longevity of plastic litter at the sea floor is poorly constrained. The present study compares colonization and biodegradation of plastic bags by aerobic and anaerobic benthic microbes in temperate fine-grained organic-rich marine sediments. Samples of polyethylene and biodegradable plastic carrier bags were incubated in natural oxic and anoxic sediments from Eckernförde Bay (Western Baltic Sea) for 98days. Analyses included (1) microbial colonization rates on the bags, (2) examination of the surface structure, wettability, and chemistry, and (3) mass loss of the samples during incubation. On average, biodegradable plastic bags were colonized five times higher by aerobic and eight times higher by anaerobic microbes than polyethylene bags. Both types of bags showed no sign of biodegradation during this study. Therefore, marine sediment in temperate coastal zones may represent a long-term sink for plastic litter and also supposedly compostable material.
Mostrar más [+] Menos [-]Pollutant levels in discarded fish species by Spanish trawlers operating in the Great Sole Bank and the Atlantic coast of the Iberian Peninsula Texto completo
2016
Pollutant levels in discarded fish species by Spanish trawlers operating in the Great Sole Bank and the Atlantic coast of the Iberian Peninsula Texto completo
2016
Organic and inorganic pollutant levels were determined for the most discarded species from trawlers operating in Great Sole and Spanish coastal fishing grounds. Results for heavy metals indicated that Cd can reach values higher than legal limits for some species and tissues, while Hg and Pb concentrations are below established values. No significant variation was noticed with fishing grounds, but both season influences in the case of Pb and interspecies variation for Hg and Cd have been detected. Valorization recommendations could be therefore established according to the levels found in the different species.
Mostrar más [+] Menos [-]Pollutant levels in discarded fish species by Spanish trawlers operating in the Great Sole Bank and the Atlantic coast of the Iberian Peninsula Texto completo
2016
Antelo, L. T. | Ordóñez, Tatiana | Lopes, Carla | Franco-Uría, A. | Pérez Martín, Ricardo Isaac | Alonso, Antonio A.
8 páginas, 5 tablas, 1 figura | Organic and inorganic pollutant levels were determined for the most discarded species from trawlers operating in Great Sole and Spanish coastal fishing grounds. Results for heavy metals indicated that Cd can reach values higher than legal limits for some species and tissues, while Hg and Pb concentrations are below established values. No significant variation was noticed with fishing grounds, but both season influences in the case of Pb and interspecies variation for Hg and Cd have been detected. Valorization recommendations could be therefore established according to the levels found in the different species | The authors acknowledge the financial support received from the LIFE + Program of the European Union (FAROS Project — LIFE08 ENV/E/000119, LIFE iSEAS Project — LIFE13 ENV/ES/000131). Amaya Franco-Uría belongs to the Galician Competitive Research Group GRC 2013-032, program co-funded by ERDF, and to CRETUS (AGRUP2015/02). Amaya Franco-Uría and Luis T. Antelo would also like to thank Secretaría de Estado de Investigación, Desarrollo e Innovación for the support provided by the “Ramón y Cajal” Subprogram. | Peer reviewed
Mostrar más [+] Menos [-]Release of synthetic microplastic plastic fibres from domestic washing machines: Effects of fabric type and washing conditions Texto completo
2016
Washing clothes made from synthetic materials has been identified as a potentially important source of microscopic fibres to the environment. This study examined the release of fibres from polyester, polyester-cotton blend and acrylic fabrics. These fabrics were laundered under various conditions of temperature, detergent and conditioner. Fibres from waste effluent were examined and the mass, abundance and fibre size compared between treatments. Average fibre size ranged between 11.9 and 17.7μm in diameter, and 5.0 and 7.8mm in length. Polyester-cotton fabric consistently shed significantly fewer fibres than either polyester or acrylic. However, fibre release varied according to wash treatment with various complex interactions. We estimate over 700,000 fibres could be released from an average 6kg wash load of acrylic fabric. As fibres have been reported in effluent from sewage treatment plants, our data indicates fibres released by washing of clothing could be an important source of microplastics to aquatic habitats.
Mostrar más [+] Menos [-]Rapid assessment of target species: Byssate bivalves in a large tropical port Texto completo
2016
Rapid assessment sampling for target species is a fast cost-effective method aimed at determining the presence, abundance and distribution of alien and native harmful aquatic organisms and pathogens that may have been introduced by shipping. In this study, the method was applied within a large tropical port expected to have a high species diversity. The port of Kaohsiung was sampled for bivalve molluscan species that attach using a byssus. Such species, due to their biological traits, are spread by ships to ports worldwide. We estimated the abundance and distribution range of one dreissenid (Mytilopsis sallei) and four mytilids (Brachidontes variabilis, Arcuatula senhousa, Mytilus galloprovincialis, Perna viridis) known to be successful invaders and identified as potential pests, or high-risk harmful native or non-native species. We conclude that a rapid assessment of their abundance and distribution within a port, and its vicinity, is efficient and can provide sufficient information for decision making by port managers where IMO port exemptions may be sought.
Mostrar más [+] Menos [-]A- DROP: A predictive model for the formation of oil particle aggregates (OPAs) Texto completo
2016
Zhao, Lin | Boufadel, Michel C. | Geng, Xiaolong | Lee, Kenneth | King, Thomas | Robinson, Brian | Fitzpatrick, Faith
Oil–particle interactions play a major role in removal of free oil from the water column. We present a new conceptual–numerical model, A-DROP, to predict oil amount trapped in oil–particle aggregates. A new conceptual formulation of oil–particle coagulation efficiency is introduced to account for the effects of oil stabilization by particles, particle hydrophobicity, and oil–particle size ratio on OPA formation. A-DROP was able to closely reproduce the oil trapping efficiency reported in experimental studies. The model was then used to simulate the OPA formation in a typical nearshore environment. Modeling results indicate that the increase of particle concentration in the swash zone would speed up the oil–particle interaction process; but the oil amount trapped in OPAs did not correspond to the increase of particle concentration. The developed A-DROP model could become an important tool in understanding the natural removal of oil and developing oil spill countermeasures by means of oil–particle aggregation.
Mostrar más [+] Menos [-]A limited legacy effect of copper in marine biofilms Texto completo
2016
McElroy, David J. | Doblin, Martina A. | Murphy, Richard J. | Hochuli, Dieter F. | Coleman, Ross A.
The effects of confounding by temporal factors remains understudied in pollution ecology. For example, there is little understanding of how disturbance history affects the development of assemblages. To begin addressing this gap in knowledge, marine biofilms were subjected to temporally-variable regimes of copper exposure and depuration. It was expected that the physical and biological structure of the biofilms would vary in response to copper regime. Biofilms were examined by inductively coupled plasma optical emission spectrometry, chlorophyll-a fluorescence and field spectrometry and it was found that (1) concentrations of copper were higher in those biofilms exposed to copper, (2) concentrations of copper remain high in biofilms after the source of copper is removed, and (3) exposure to and depuration from copper might have comparable effects on the photosynthetic microbial assemblages in biofilms. The persistence of copper in biofilms after depuration reinforces the need for consideration of temporal factors in ecology.
Mostrar más [+] Menos [-]The impact of long-term hydrocarbon exposure on the structure, activity, and biogeochemical functioning of microbial mats Texto completo
2016
Aubé, Johanne | Senin, Pavel | Pringault, Olivier | Bonin, Patricia | Deflandre, Bruno | Bouchez, Olivier | Bru, Noëlle | Biritxinaga-Etchart, Edurne | Klopp, Christophe | Guyoneaud, Rémy | Goñi-Urriza, Marisol
The impact of long-term hydrocarbon exposure on the structure, activity, and biogeochemical functioning of microbial mats Texto completo
2016
Aubé, Johanne | Senin, Pavel | Pringault, Olivier | Bonin, Patricia | Deflandre, Bruno | Bouchez, Olivier | Bru, Noëlle | Biritxinaga-Etchart, Edurne | Klopp, Christophe | Guyoneaud, Rémy | Goñi-Urriza, Marisol
Photosynthetic microbial mats are metabolically structured systems driven by solar light. They are ubiquitous and can grow in hydrocarbon-polluted sites. Our aim is to determine the impact of chronic hydrocarbon contamination on the structure, activity, and functioning of a microbial mat. We compared it to an uncontaminated mat harboring similar geochemical characteristics. The mats were sampled in spring and fall for 2years. Seasonal variations were observed for the reference mat: sulfur cycle-related bacteria dominated spring samples, while Cyanobacteria dominated in autumn. The contaminated mat showed minor seasonal variation; a progressive increase of Cyanobacteria was noticed, indicating a perturbation of the classical seasonal behavior. Hydrocarbon content was the main factor explaining the differences in the microbial community structure; however, hydrocarbonoclastic bacteria were among rare or transient Operational Taxonomic Units (OTUs) in the contaminated mat. We suggest that in long-term contaminated systems, hydrocarbonoclastic bacteria cannot be considered a sentinel of contamination.
Mostrar más [+] Menos [-]The impact of long-term hydrocarbon exposure on the structure, activity, and biogeochemical functioning of microbial mats Texto completo
2016
Aubé, Johanne | Senin, Pavel | Pringault, Olivier | Bonin, Patricia | Deflandre, Bruno | Bouchez, Olivier | Bru, Noëlle | Biritxinaga-Etchart, Edurne | Klopp, Christophe | Guyoneaud, Remy | Goñi, Marisol | Los Alamos National Laboratory (LANL) | Ecologie des systèmes marins côtiers (Ecosym) ; Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS) | Institut méditerranéen d'océanologie (MIO) ; Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS) | Environnements et Paléoenvironnements OCéaniques (EPOC) ; École Pratique des Hautes Études (EPHE) ; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) | Laboratoire de Génétique Cellulaire (LGC) ; Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Vétérinaire de Toulouse (ENVT) ; Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)-Université de Toulouse (UT) | Laboratoire de Mathématiques et de leurs Applications [Pau] (LMAP) ; Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS) | Unité de Biométrie et Intelligence Artificielle (ancêtre de MIAT) (UBIA) ; Institut National de la Recherche Agronomique (INRA) | Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM) ; Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS) | French National Research Agency (ANR FUNHYMAT) [ANR11 BSV7 014 01]
International audience | Photosynthetic microbial mats are metabolically structured systems driven by solar light. They are ubiquitous and can grow in hydrocarbon-polluted sites. Our aim is to determine the impact of chronic hydrocarbon contamination on the structure, activity, and functioning of a microbial mat. We compared it to an uncontaminated mat harboring similar geochemical characteristics. The mats were sampled in spring and fall for 2 years. Seasonal variations were observed for the reference mat: sulfur cycle-related bacteria dominated spring samples, while Cyanobacteria dominated in autumn. The contaminated mat showed minor seasonal variation; a progressive increase of Cyanobacteria was noticed, indicating a perturbation of the classical seasonal behavior. Hydrocarbon content was the main factor explaining the differences in the microbial community structure; however, hydrocarbonoclastic bacteria were among rare or transient Operational Taxonomic Units (OTUs) in the contaminated mat. We suggest that in long-term contaminated systems, hydrocarbonoclastic bacteria cannot be considered a sentinel of contamination
Mostrar más [+] Menos [-]Investigation on VOC Emissions from Automobile Sources by Means of Online Mass Spectrometry Texto completo
2016
Inomata, Satoshi | Yamada, Hiroyuki | Tanimoto, Hiroshi
This study reviews recent research on volatile organic compound (VOC) emissions from motorized vehicle sources by means of online mass spectrometry. Chemical ionization is a powerful tool that usually permits soft ionization of chemical species and it allows the time-resolved measurement of multiple VOCs, even in complex samples where many kinds of VOCs coexist. The vehicular exhaust gasses are investigated using H₃O⁺, NO⁺, Hg⁺, and CH₃C(O)O⁻ as a reagent ion in online chemical ionization mass spectrometry. The proton transfer using H₃O⁺ as a reagent ion was used for the detection of nitro-organic compounds such as nitromethane and nitrophenol. The time-resolved measurement of the nitro-organic compounds in the laboratory experiments with a chassis dynamometer system revealed their emission properties, such as the dependence of the emissions as a function of vehicular velocity and acceleration/deceleration, as well as the effect of various types of exhaust gas treatment. The data regarding the nitromethane and nitrophenol emissions obtained in the field measurements were consistent with the results of the laboratory experiments done with a chassis dynamometer system. In the experiments involving evaporative emissions from gasoline-powered cars, NO⁺ was used as a reagent ion. Online measurements showed that the adsorption of hydrocarbons in a sealed housing evaporative determination unit could result in emissions being underestimated, if the concentrations are monitored only before and after a diurnal breathing loss test. The composition analysis gave an estimated ozone formation potential (OFP) approximately 20 % higher for breakthrough emissions and refueling emissions than for the gasoline that was tested, but the OFP for the permeation emissions was almost the same as the OFP for the test fuel.
Mostrar más [+] Menos [-]