خيارات البحث
النتائج 781 - 790 من 1,956
Titanium determination by multisyringe flow injection analysis system and a liquid waveguide capillary cell in solid and liquid environmental samples النص الكامل
2013
Sánchez-Quiles, David | Tovar-Sánchez, Antonio | Horstkotte, Burkhard
A multisyringe flow injection analysis system using a liquid waveguide capillary cell (MSFIA-LWCC) has been used for the spectrophotometric determination of titanium (Ti) in marine environmental samples. Samples were previous digested using potassium peroxodisulfate (K2S2O8). The method showed to be linear over a range up to 1μM with a detection limit of 9.2nM. The analysis consumes little reagent (250μL) and sample (600μL). It had an adequate accuracy with high repeatability (RSD of 1.8%) for all marine samples. The proposed method was used to evaluate the concentration of Ti in natural samples collected in the coastal area of the Majorca Island (Western Mediterranean Sea). We report average concentrations of Ti in coastal surface microlayer of 510.7±267.2nM, in surface sediments of 2.72±1.84μmol/g, and in rhizomes and leaves of Posidonia oceanica of 310±295nmol/g and 157±132nmol/g, respectively.
اظهر المزيد [+] اقل [-]Mercury biomagnification in a contaminated estuary food web: Effects of age and trophic position using stable isotope analyses النص الكامل
2013
Coelho, J.P. | Mieiro, C.L. | Pereira, E. | Duarte, A.C. | Pardal, M.A.
The main aim of this study was to ascertain the biomagnification processes in a mercury-contaminated estuary, by clarifying the trophic web structure through stable isotope ratios. For this purpose, primary producers (seagrasses and macroalgae), invertebrates (detritivores and benthic predators) and fish were analysed for total and organic mercury and for stable carbon and nitrogen isotopic signatures. Trophic structure was accurately described by δ15N, while δ13C reflected the carbon source for each species. An increase of mercury levels was observed with trophic level, particularly for organic mercury. Results confirm mercury biomagnification to occur in this estuarine food web, especially in the organic form, both in absolute concentrations and fraction of total mercury load. Age can be considered an important variable in mercury biomagnification studies, and data adjustments to account for the different exposure periods may be necessary for a correct assessment of trophic magnification rates and ecological risk.
اظهر المزيد [+] اقل [-]Monitoring of a wide range of organic micropollutants on the Portuguese coast using plastic resin pellets النص الكامل
2013
Mizukawa, Kaoruko | Takada, Hideshige | Ito, Maki | Geok, Yeo Bee | Hosoda, Junki | Yamashita, Rei | Saha, Mahua | Suzuki, Satoru | Miguez, Carlos | Frias, João | Antunes, Joana Cepeda | Sobral, Paula | Santos, Isabelina | Micaêlo, Cristina | Ferreira, Ana María
We analyzed polychlorinated biphenyls (PCBs), dichlorodiphenyl dichloroethane and its metabolites, hexachlorocyclohexanes (HCHs), polycyclic aromatic hydrocarbons (PAHs), and hopanes, in plastic resin pellets collected from nine locations along the Portuguese coast. Concentrations of a sum of 13 PCBs were one order of magnitude higher in two major cities (Porto: 307ng/g-pellet; Lisboa: 273ng/g-pellet) than in the seven rural sites. Lower chlorinated congeners were more abundant in the rural sites than in the cities, suggesting atmospheric dispersion. At most of the locations, PAH concentrations (sum of 33 PAH species) were ∼100 to ∼300ng/g-pellet; however, three orders of magnitude higher concentrations of PAHs, with a petrogenic signature, were detected at a small city (Sines). Hopanes were detected in the pellets at all locations. This study demonstrated that multiple sample locations, including locations in both urban and remote areas, are necessary for country-scale pellet watch.
اظهر المزيد [+] اقل [-]Extreme irgarol tolerance in an Ulva lactuca L. population on the Swedish west coast النص الكامل
2013
Wendt, Ida | Arrhenius, Åsa | Backhaus, Thomas | Hilvarsson, Annelie | Holm, Christina | Langford, Katherine | Tunovic, Timur | Blanck, Hans
The herbicide irgarol 1051 is commonly used on ship hulls to prevent growth of algae, but as a component of self-eroding paints it can also spread in the surrounding waters and affect non-target organisms. The effect of irgarol on settlement and growth of zoospores from the marine macro algae Ulva lactuca from the Gullmar fjord on the Swedish west coast was investigated in the present study. The zoospores were allowed to settle and grow in the presence of irgarol, but neither settlement – nor growth inhibition was observed at concentrations of up to 2000nmoll−1. This is between 10 and 100 times higher than effect concentrations reported earlier for algae. Irgarol also induced the greening effect (4-fold increase in chlorophyll a content) in the settled zoospore/germling population, typical for photosystem II inhibitors like irgarol. This study support previous findings that irgarol constitutes a selection pressure in the marine environment.
اظهر المزيد [+] اقل [-]As main meal for sperm whales: Plastics debris النص الكامل
2013
de Stephanis, Renaud | Giménez, Joan | Carpinelli, Eva | Gutierrez-Exposito, Carlos | Cañadas, Ana
Marine debris has been found in marine animals since the early 20th century, but little is known about the impacts of the ingestion of debris in large marine mammals. In this study we describe a case of mortality of a sperm whale related to the ingestion of large amounts of marine debris in the Mediterranean Sea (4th published case worldwide to our knowledge), and discuss it within the context of the spatial distribution of the species and the presence of anthropogenic activities in the area that could be the source of the plastic debris found inside the sperm whale. The spatial distribution modelled for the species in the region shows that these animals can be seen in two distinct areas: near the waters of Almería, Granada and Murcia and in waters near the Strait of Gibraltar. The results shows how these animals feed in waters near an area completely flooded by the greenhouse industry, making them vulnerable to its waste products if adequate treatment of this industry’s debris is not in place. Most types of these plastic materials have been found in the individual examined and cause of death was presumed to be gastric rupture following impaction with debris, which added to a previous problem of starvation. The problem of plastics arising from greenhouse agriculture should have a relevant section in the conservation plans and should be a recommendation from ACCOBAMS due to these plastics’ and sperm whales’ high mobility in the Mediterranean Sea.
اظهر المزيد [+] اقل [-]Major and minor element geochemistry of deep-sea sediments in the Azores Platform and southern seamount region النص الكامل
2013
Palma, Carla | Oliveira, Anabela | Valença, Manuela | Cascalho, João | Pereira, Eduarda | Lillebø, Ana I. | Duarte, Armando C. | Pinto de Abreu, Manuel
The Azores Platform and the Irving and Great Meteor seamounts south of the archipelago (38°N–29°N) have rarely been studied geochemically, a fact which is surprising given that they represent the south-eastern limit of region V outlined in the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR Convention). The main aim of the present work was therefore to characterise the spatial variability of major and minor elements in deep-sea sediment cores from these two regions. XRD and geochemical analyses revealed that whereas the Azores Platform sediments are composed of a mixture of biogenic and detrital volcanic material, those at the seamounts are characterised by carbonated biogenic remains. The latter sediments were found to contain very low amounts of volcanic or hydrothermal detrital material, being almost entirely comprised of CaCO3 (more than 80%).
اظهر المزيد [+] اقل [-]Processing of fecal sludge to fertilizer pellets using a low-cost technology in Ghana النص الكامل
2013
Nikiema, Josiane | Cofie, Olufunke | Impraim, Robert | Adamtey, N.
This paper describes a study that was aimed at optimizing the pelletization of fecal sludge-based fertilizers for agricultural use. The process developed is easy to implement and increases the marketability of the products while also addressing a serious health and environmental challenge. The study took place during the period 2011-2012 in Ghana. The fecal sludge, rich in nutrients and organic matter, was dried and used to produce five different fertilizers (i.e., four formulations of compost and one with gamma irradiated material). Each material was then pelletized using locally constructed machinery. Key operating parameters, such as moisture content (10-55% in mass), binder type (clay or starch) and concentration (0-10% in mass), were varied and their impacts on the characteristics of pellets (e.g., amount of fine materials generated, length distribution or stability of pellets, and pellet disintegration rate) were also followed. Given the low analyzing capabilities of developing countries, some simple analytical methods were developed and used to compare pellets produced under different conditions. The results confirmed that the addition of 3% of pregelatinized starch is recommended during pelletization of fecal sludge-based fertilizers. Applicable moisture contents were also identified per fertilizer type, and were found to comprise between 21 and 43%.
اظهر المزيد [+] اقل [-]Recent innovation in microbial source tracking using bacterial real-time PCR markers in shellfish النص الكامل
2013
Mauffret, Aourell | Mieszkin, Sophie | Morizur, Mael | Alfiansah, Yustian Rovi | Lozach, Solen | Gourmelon, Michele
Recent innovation in microbial source tracking using bacterial real-time PCR markers in shellfish النص الكامل
2013
Mauffret, Aourell | Mieszkin, Sophie | Morizur, Mael | Alfiansah, Yustian Rovi | Lozach, Solen | Gourmelon, Michele
We assessed the capacity of real-time PCR markers to identify the origin of contamination in shellfish. Oyster, cockles or clams were either contaminated with fecal materials and host-associated markers designed from Bacteroidales or Catellicoccus marimammalium 16S RNA genes were extracted from their intravalvular liquid, digestive tissues or shellfish flesh. Extraction of bacterial DNA from the oyster intravalvular liquid with FastDNA spin kit for soil enabled the selected markers to be quantified in 100% of artificially contaminated samples, and the source of contamination to be identified in 13 out of 38 naturally contaminated batches from European Class B and Class C areas. However, this protocol did not enable the origin of the contamination to be identified in cockle or clam samples. Although results are promising for extracts from intravalvular liquid in oyster, it is unlikely that a single protocol could be the best across all bacterial markers and types of shellfish. (C) 2013 Elsevier Ltd. All rights reserved.
اظهر المزيد [+] اقل [-]Recent innovation in microbial source tracking using bacterial real-time PCR markers in shellfish النص الكامل
2013
Mauffret, A. | Mieszkin, S. | Morizur, M. | Alfiansah, Y. | Lozach, S. | Gourmelon, M.
We assessed the capacity of real-time PCR markers to identify the origin of contamination in shellfish. Oyster, cockles or clams were either contaminated with fecal materials and host-associated markers designed from Bacteroidales or Catellicoccus marimammalium 16S RNA genes were extracted from their intravalvular liquid, digestive tissues or shellfish flesh. Extraction of bacterial DNA from the oyster intravalvular liquid with FastDNA spin kit for soil enabled the selected markers to be quantified in 100% of artificially contaminated samples, and the source of contamination to be identified in 13 out of 38 naturally contaminated batches from European Class B and Class C areas. However, this protocol did not enable the origin of the contamination to be identified in cockle or clam samples. Although results are promising for extracts from intravalvular liquid in oyster, it is unlikely that a single protocol could be the best across all bacterial markers and types of shellfish.
اظهر المزيد [+] اقل [-]Merchant ships discharging unwanted marine species in close proximity of a French aquaculture area: Risks involved النص الكامل
2013
Masson, Daniel | Thomas, Gerard | Genauzeau, Sylvie | Le Moine, Olivier | Derrien, Annick
Merchant ships discharging unwanted marine species in close proximity of a French aquaculture area: Risks involved النص الكامل
2013
Masson, Daniel | Thomas, Gerard | Genauzeau, Sylvie | Le Moine, Olivier | Derrien, Annick
The most important oyster farming area in Europe is in a close proximity of two medium size merchant ports. Cargo ships deballast in this area before loading, releasing unwanted or noxious marine species. During a sampling campaign aboard these arriving ships, we found in some ballast water samples a huge number of potentially toxic dinoflagellates and some potentially pathogenic bacteria. A model was applied to find the potential geographical spread of the discharged ballast water. This model predicts the water to reach highly vulnerable shellfish farmed areas in six to eight days.
اظهر المزيد [+] اقل [-]Merchant ships discharging unwanted marine species in close proximity of a French aquaculture area: Risks involved النص الكامل
2013
Masson, Daniel | Thomas, Gerard | Genauzeau, Sylvie | Le Moine, Olivier | Derrien, Annick
The most important oyster farming area in Europe is in a close proximity of two medium size merchant ports. Cargo ships deballast in this area before loading, releasing unwanted or noxious marine species. During a sampling campaign aboard these arriving ships, we found in some ballast water samples a huge number of potentially toxic dinoflagellates and some potentially pathogenic bacteria. A model was applied to find the potential geographical spread of the discharged ballast water. This model predicts the water to reach highly vulnerable shellfish farmed areas in six to eight days.
اظهر المزيد [+] اقل [-]DNA strand breaks (comet assay) in blood lymphocytes from wild bottlenose dolphins النص الكامل
2013
Lee, Richard F. | Bulski, Karrie | Adams, Jeffrey D. | Peden-Adams, Margie | Bossart, Gregory D. | King, Lydia | Fair, Patricia A.
The comet assay was carried out on blood lymphocytes from a large number of wild dolphins (71 from Indian River Lagoon, FL, USA; 51 from Charleston Harbor, SC, USA) and provides a baseline study of DNA strand breaks in wild dolphin populations. There were no significant differences in the comet assay (%DNAintail) results between the different age and sex categories. Significant difference in DNA strand breaks were found between Charleston Harbor dolphins (median – 17.4%DNAintail) and Indian River Lagoon dolphins (median – 14.0%DNAintail). A strong correlation found between T-cell proliferation and DNA strand breaks in dolphin lymphocytes suggests that dolphins with a high numbers of DNA strand breaks have a decreased ability to respond to infection. Higher concentrations of genotoxic agents in Charleston Harbor compared with Indian River lagoon may have been one of the causes of higher DNA strand breaks in these dolphins.
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