خيارات البحث
النتائج 1681 - 1690 من 5,239
Litter impacts on beach/dune systems along the Atlantico Department, the Caribbean Coastline of Colombia النص الكامل
2018
Rangel-Buitrago, Nelson | Castro-Barros, Julian Dario | Adriana Gracia, C. | Villadiego, Jose Dario Villamil | Williams, Allan T.
Eight beach/dune systems located along the Atlantico Department, Caribbean coast of Colombia were surveyed to determine litter influences over its scenic quality. Application of the Coastal Scenic Evaluation System (CSES) categorized these systems into two of the five available classes. Five of the investigated beach/dune systems belong to Class IV, while three systems correspond to V. Classes I, II and III were not found. Along these beach/dune systems, a total amount of 1908 litter items were collected with average abundances of 4.2 items/m2. Currently, 82% of surveyed sites are under an unacceptable condition of cleanness. User's habits as well as bad litter management practices are directly responsible for the decline of scenic quality of the Atlantico Department beach/dune systems. Litter management must be centered on strategies to eliminate or minimize litter sources. Specific remedial actions need to be defined and developed.
اظهر المزيد [+] اقل [-]Microplastic in the gastrointestinal tract of fishes along the Saudi Arabian Red Sea coast النص الكامل
2018
Baalkhuyur, Fadiyah M. | Bin Dohaish, El-Jawaher A. | Elhalwagy, Manal E.A. | Alikunhi, Nabeel M. | AlSuwailem, Abdulaziz M. | Røstad, Anders | Coker, Darren J. | Berumen, Michael L. | Duarte, Carlos M.
This study assesses the presence of microplastic litter in the contents of the gastrointestinal tract of 26 commercial and non-commercial fish species from four difference habitats sampled along the Saudi Arabian coast of the Red Sea. A total of 178 individual were examined for microplastics. In total, 26 microplastic fragments were found. Of these, 16 being films (61.5%) and 10 being fishing thread (38.5%). FTIR analysis revealed that the most abundant polymers were polypropylene and polyethylene. Parascolosps eriomma species sampled at Jazan registered the highest number of ingested microplastic. This fish species is benthic and feeds on benthic invertebrates. Although differences in the abundance of microplastic ingestion among species were not statistically significant, a significant change was observed when the level of ingestion of microplastics particles was compared among the habitats. The higher abundance of microplastics particles may be related to the habitats of fish and the presence of microplastics debris near the seabed. The results of this study represent a first evidence that microplastic pollution represents an emerging threat to Red Sea fishes, their food web and human consumers.
اظهر المزيد [+] اقل [-]Changes to polychlorinated biphenyl (PCB) signatures and enantiomer fractions across different tissue types in Guillemots النص الكامل
2018
Megson, David | Brown, Thomas A. | O'Sullivan, Gwen | Robson, Matthew | Ortiz, Xavier | Worsfold, Paul J. | Comber, Sean | Lohan, Maeve C. | Reiner, Eric J.
Two Guillemot carcases were dissected, each providing 12 discrete tissue samples and 3 samples of partially digested food. One hundred and five PCBs from the 209 PCBs determined by GCxGC-ToFMS were detected. The relative proportions of individual PCBs did not vary greatly within tissue types, although the PCB profile from undigested food could be distinguished. Enantiomer fractions (EFs) were determined for CB-95, CB-136 and CB-149 by GC-HRqToFMS. EFs in the partially digested food were near racemic, with high levels of enrichment for E1 CB-95 in the kidneys and liver (EF of 0.80 and 0.84 respectively). This provides some of the clearest evidence to date that fractionation takes place in the organs where metabolic biotransformation and elimination of PCBs occurs. Our findings also confirm the ability of non-lethal sampling techniques, such as collection of small (<1 g) blood samples, to provide PCB signatures that are representative of an individual organism.
اظهر المزيد [+] اقل [-]Evaluation of toxicity of Deepwater Horizon slick oil on spat of the oyster Crassostrea virginica النص الكامل
2018
Vignier, Julien | Rolton, Anne | Soudant, Philippe | Chu, Fu-lin E. | Robert, Rene | Volety, Aswani K.
The 2010 explosion of the Deepwater Horizon (DWH) oil rig generated the largest marine oil spill in US history with millions of barrels of crude oil released in the Gulf of Mexico (GoM). The eastern oyster, Crassostrea virginica, is an ecologically and economically important species in the northern GoM. Due to its biological characteristics (sessile, filter feeding), juvenile oysters may have been affected. This study investigated the effects of surface-collected DWH oil prepared as high-energy water-accommodated fraction (HEWAF) on the survival of 2-month-old oyster spat, and evaluated the potential impacts of HEWAF on particle clearance rate and spat tissue. Exposure of oysters to a range of oil/HEWAF (0-7-66-147-908-3450 mu g tPAH50 (sum of 50 polycyclic aromatic hydrocarbons) L-1) resulted in non-dose-dependent mortalities and reduced clearance rates of algal food (Tisochrysis lutea). A morphometric study of the digestive tubules (DGTs) indicated a dose-dependent response to oil exposure on lumen dilation, on epithelium thinning of the DGT, and a significant change in DGT synchrony (LOEC = 66 mu g tPAH50 L-1). This finding suggests that structural changes occurred in the digestive gland of exposed oysters most likely due to an oil-related stress. In addition, histological observations showed that tissues in contact with HEWAF (gills, palp, connective tissue, digestive gland) were adversely impacted at >= 7 mu g tPAH50 L-1, and exhibited pathological symptoms typical of an inflammatory response (e.g., hemocyte diapedesis and infiltration, syncytia, epithelium sloughing).
اظهر المزيد [+] اقل [-]Seasonal biomass and alginate stock assessment of three abundant genera of brown macroalgae using multispectral high resolution satellite remote sensing: A case study at Ekas Bay (Lombok, Indonesia) النص الكامل
2018
Setyawidati, Nur Azmi R. | Puspita, Maya | Kaimuddin, Awaludin H. | Widowati, Ita | Deslandes, Eric | Bourgougnon, Nathalie | Stiger-pouvreau, Valerie
Seasonal biomass and alginate stock assessment of three abundant genera of brown macroalgae using multispectral high resolution satellite remote sensing: A case study at Ekas Bay (Lombok, Indonesia) النص الكامل
2018
Setyawidati, Nur Azmi R. | Puspita, Maya | Kaimuddin, Awaludin H. | Widowati, Ita | Deslandes, Eric | Bourgougnon, Nathalie | Stiger-pouvreau, Valerie
The potential of Indonesian bays as alginate producers was assessed by determining the stock of wild brown algae and exploring their biomass as alginophytes at the scale of entire bay, using a combination of field observations, remote sensing high resolution data and GIS tools. Ekas Bay in Lombok Island presented a stock of brown macroalgae which varied with season and species: for Padina the biomass reached 97.85 +/- 12.63 and 79.54 +/- 2.53 tons in May/June and November respectively; for Sargassaceae species, it reached 669.70 +/- 109.64 and 147.70 +/- 77.97 tons in May/June and November respectively. The best alginate yields occurred during the May/June period: Padina could produce 9.10 +/- 0.06 tons DW of alginates. Interestingly, Sargassurn/Turbinaria together allow 207.61 +/- 0.42 tons DW of alginates. This study suggests that wild Sargassaceae represent an interesting stock in terms of biomass, alginate yield and M/G ratio.
اظهر المزيد [+] اقل [-]Seasonal biomass and alginate stock assessment of three abundant genera of brown macroalgae using multispectral high resolution satellite remote sensing: A case study at Ekas Bay (Lombok, Indonesia) النص الكامل
2018
Setyawidati, Nur Azmi R. | Puspita, Maya | Kaimuddin, Awaludin H. | Widowati, Ita | Deslandes, Eric | Bourgougnon, Nathalie | Stiger-Pouvreau, Valérie
The potential of Indonesian bays as alginate producers was assessed by determining the stock of wild brown algae and exploring their biomass as alginophytes at the scale of entire bay, using a combination of field observations, remote sensing high resolution data and GIS tools. Ekas Bay in Lombok Island presented a stock of brown macroalgae which varied with season and species: for Padina the biomass reached 97.85±12.63 and 79.54±2.53tons in May/June and November respectively; for Sargassaceae species, it reached 669.70±109.64 and 147.70±77.97tons in May/June and November respectively. The best alginate yields occurred during the May/June period: Padina could produce 9.10±0.06tons DW of alginates. Interestingly, Sargassum/Turbinaria together allow 207.61±0.42tons DW of alginates. This study suggests that wild Sargassaceae represent an interesting stock in terms of biomass, alginate yield and M/G ratio.
اظهر المزيد [+] اقل [-]Potential risk of mercury to human health in three species of fish from the southern Caspian Sea النص الكامل
2018
Manavi, Parisa Nejatkhah | Mazumder, Asit
We aimed to investigate mercury level in three species of fish such as Sander lucioperca, Liza aurata, and Rutilus frisii kutum. Sampling was done in the southern coasts of the Caspian Sea. The ranges of mercury level in S. lucioperca, L. aurata, and R. frisii kutum were 104.67–675.33 ppb, 60.66–175.33 ppb, and 123.33–170.33 ppb, respectively. Results revealed that the mercury level in S. lucioperca was more than the allowable limit at several sites, while it was less than the allowable limit in R. frisii kutum and L. aurata at all sampling sites. Further, the target hazard quotient (THQ) index for S. lucioperca was >1 at some sites and <1 for other species at all sites. The maximum allowable consumption for each species at the study area was measured daily and monthly.
اظهر المزيد [+] اقل [-]Hexabromocyclododecanes (HBCDs) in fish: Evidence of recent HBCD input into the coastal environment النص الكامل
2018
Sun, Runxia | Luo, Xiaojun | Zheng, Xiaobo | Fanhuolaoren, | Peng, Pingan | Li, Qing X. | Mai, Bixian
Hexabromocyclododecanes (HBCDs) are flame retardants and emerging persistent organic pollutants. In the present study, α-, β-, and γ-HBCDs were measured in several fish species from rivers and an electronic waste (e-waste) recycling site in Pearl River Delta, South China. The concentrations of HBCDs were 12.8 to 640, 5.90 to 115, and 34.3 to 518ng/g lipid weight (lw) in mud carp (Cirrhinus molitorella), tilapia (Tilapia nilotica), and plecostomus (Hypostomus plecostomus), respectively. Plecostomus showed the highest HBCD concentrations among three fish species. The contributions of α-HBCD to total HBCDs were 78% to 97%, 93% to 99%, and 87% to 98% in carp, tilapia, and plecostomus, respectively. Fish samples from a harbor and the e-waste site exhibited the highest HBCD concentrations among all samples. The HBCD concentrations were not significantly correlated with the gross domestic product or population data. e-Waste recycling activities, harbor construction, and shipment might be recent HBCD sources.
اظهر المزيد [+] اقل [-]Organochlorine pesticides in surface waters from Reloncaví Fjord and the inner sea of Chiloé (~39.5°S - 43°S), Chilean Patagonia النص الكامل
2018
Placencia, Juan A. | Contreras, Sergio
Surface water samples from the environmental continuum spanning rivers (Petrohue, Cochamo, Puelo), fjord (Reloncaví), and the inner sea of Chiloé in Chilean Patagonia were analyzed to estimate concentration and distribution of dissolved Organochlorine pesticides (OCPs). High concentrations of HCHs, DDTs and endosulfan found in surface waters from rivers suggest that rivers are the major source of dissolved OCPs to coastal marine ecosystems. We interpret variations in the distribution and concentration as an apparent oscillation between rain and snow-scavenging processes that might determine the type of OCPs that can be preferentially deposited on mountains, glaciers, rivers, estuaries, and finally transferred to the marine realm. Predominance of α-HCH, γ-HCH, p,p′-DDE and α-endosulfan compounds suggest that the main deposition mechanism of OCPs to the Chilean Patagonia is rain scavenging. Snow and rain can be additional sources of OCPs that must be considered for future studies in fjord systems in Chilean Patagonia.
اظهر المزيد [+] اقل [-]Concentrations of selected radionuclides and their spatial distribution in marine sediments from the northwestern Gulf, Kuwait النص الكامل
2018
Uddin, Saif | Behbehani, Montaha
This study focuses on creating a baseline for ⁴⁰K, ²¹⁰Pb, ¹³⁷Cs, ⁹⁰Sr, ²²⁶Ra, ²²⁸Ra, ²³⁸U, ²³⁵U, ²³⁴U, ²³⁹⁺²⁴⁰Pu and ²³⁸Pu in marine sediments in the northwestern Gulf. The respective measured concentration ranges were 386–489, 32.3–48.8, 1.5–2.9, 4.53–5.42, 18.3–23.1, 18.8–23.0, 22.3–30.5, 0.99–1.33, 25.6–34.8, 0.30–0.93, and 0.0008–0.00018Bqkg⁻¹. The levels of these radionuclides are generally comparable to values reported for other marine waters in the northern hemisphere. The ¹³⁷Cs activity in the Gulf sediments offshore Kuwait is an order of magnitude lower compared to sediments from northeastern Iran. Other than that finding, no hot spots were observed in sediments adjacent to power and desalination plants, oil and gas industrial activities or wastewater treatment facilities. These data will serve as a baseline to gauge possible future inputs of radionuclides in the northern Gulf. The calculated average ratio of ²³⁵U/²³⁸U activity in the area is in agreement with the reported figure of the natural uranium ratio, suggesting the absence of depleted uranium (DU) at all the stations. The low concentration of ²³⁹⁺²⁴⁰Pu suggests that there is no significant source of plutonium except that from atmospheric fallout from weapon testing and possible dry deposition via long-range dust transport.
اظهر المزيد [+] اقل [-]Biodegradation of dispersed oil in seawater is not inhibited by a commercial oil spill dispersant النص الكامل
2018
Brakstad, Odd G. | Ribicic, Deni | Winkler, Anika | Netzer, Roman
Chemical dispersants are well-established as oil spill response tools. Several studies have emphasized their positive effects on oil biodegradation, but recent studies have claimed that dispersants may actually inhibit the oil biodegradation process. In this study, biodegradation of oil dispersions in natural seawater at low temperature (5°C) was compared, using oil without dispersant, and oil premixed with different concentrations of Slickgone NS, a widely used oil spill dispersant in Europe. Saturates (nC10-nC36 alkanes), naphthalenes and 2- to 5-ring polycyclic aromatic hydrocarbons (PAH) were biotransformed at comparable rates in all dispersions, both with and without dispersant. Microbial communities differed primarily between samples with or without oil, and they were not significantly affected by increasing dispersant concentrations. Our data therefore showed that a common oil spill dispersant did not inhibit biodegradation of oil at dispersant concentrations relevant for response operations.
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