خيارات البحث
النتائج 781 - 790 من 3,243
Trace metal variability in coastal waters of San Jorge Bay, Antofagasta, Chile: An environmental evaluation and statistical approach to propose local background levels
2015
Valdés, J. | Román, D. | Guiñez, M. | Rivera, L. | Ávila, J. | Cortés, P. | Castillo, A.
Between 2008 and 2011, twelve metals from 384 coastal waters samples from San Jorge Bay (Antofagasta, northern Chile) were collected and analyzed. The goal was to evaluate the quality of the bay's water bodies according to the current Chilean Quality Guideline and to establish background levels for these metals.The result suggests that the coastal waters of San Jorge Bay are of very good quality suitable for recreational activities involving human body contact. The natural background thresholds established for this bay were significantly lower than primary and secondary water quality guidelines. The distribution of Cu, Zn and Pb, along the bay's coastline provides evidence of the effects of industrial activity. Both situations suggest that the threshold indicated in the environmental guidelines of the Chilean legislation may be overestimated and do not represent pollution-free environments.
اظهر المزيد [+] اقل [-]Inspection of high–concentration CO2 events at the Plateau Rosa Alpine station
2015
Ferrarese, Silvia | Apadula, Francesco | Bertiglia, Fabio | Cassardo, Claudio | Ferrero, Andrea | Fialdini, Lucio | Francone, Caterina | Heltai, Daniela | Lanza, Andrea | Longhetto, Arnaldo | Manfrin, Massimiliano | Richiardone, Renzo | Vannini, Claudio
The Plateau Rosa Alpine station (Italy) has collected atmospheric concentrations of carbon dioxide since 1989. If the complete set of hourly data is observed, two distinct and exceptional very high concentration events are evident for February 2004. Similar and almost contemporary peaks were registered at the European high–altitude stations of Zugspitze–Schneefernerhaus and Sonnblick in the Alps, and at Mt. Cimone in the Northern Apennines. A regional meteorological model (the Weather Research and Forecast) was applied over a medium–high resolution grid to study the evolution of the meteorological fields and to identify the trajectories of the polluted air masses during the CO2 observed peaks. The results show that, during both episodes, atmospheric circulation conveyed highly polluted air from the European plains to the Alpine stations. This conclusion has been also confirmed through concentration measurements of the atmospheric trace gases in the same area.
اظهر المزيد [+] اقل [-]Mercury distribution, methylation and volatilization in microcosms with and without the sea anemone Bunodosoma caissarum
2015
Rizzini Ansari, Nafisa | Correia, Raquel Rose Silva | Fernandez, Marcos Antônio | Cordeiro, Renato Campello | Guimarães, Jean Remy Davée
Mercury (Hg) has a complex biogeochemical cycle in aquatic environments. Its most toxic form, methylmercury (MeHg), is produced by microorganisms. This study investigated how the sea anemone Bunodosoma caissarum affects Hg distribution, methylation and volatilization in laboratory model systems. 203Hg was added to microcosms and its distribution in seawater, specimens and air was periodically measured by gamma spectrometry. MeHg was measured by liquid scintillation. After the uptake period, specimens had a bioconcentration factor of 70 and in microcosms with and without B. caissarum, respectively 0.05% and 0.32% of the initial spike was found as MeHg. After depuration, MeHg in specimens ranged from 0.2% to 2.4% of total Hg. Microcosms with B. caissarum had higher Hg volatilization (58%) than controls (17%), possibly due to Hg2+ reduction mediated by microorganisms associated with its tissues and mucus secretions. Marine organisms and their associated microbiota may play a role in Hg and MeHg cycling.
اظهر المزيد [+] اقل [-]Evaluation of steelmaking slag as basal media for coastal primary producers
2015
Akiyama, Yoshihiro B. | Yano, Hitomi | Koba, Kyohei | Katayama, Takahiro | Asaoka, Satoshi | Okuda, Tetsuji | Nakai, Satoshi | Yamamoto, Tamiji | Nishijima, Wataru
The use of granular steelmaking slag as a substitute for natural sand in the construction of tidal flats was investigated. Using an intertidal flat simulator, we evaluated dephosphorization slag mixed with 8% by dry weight of dredged sediment (DPS+DS) as a basal medium for the growth of benthic macro- and microalgae in comparison with silica sand mixed with 8% dredged sediment (SS+DS). Species compositions of macro- and microalgae were distinctly different between DPS+DS and SS+DS. The mean dry weight of macroalgae on DPS+DS was three orders of magnitude higher than that on SS+DS. Sediment shear strength and pH were higher in DPS+DS than in SS+DS or in the sediment of natural tidal flats. These results suggest that DPS contributes to changing the sediment environment, thereby changing the algal composition compared to the composition on natural tidal flats.
اظهر المزيد [+] اقل [-]Towards adaptive management of the natural capital: Disentangling trade-offs among marine activities and seagrass meadows
2015
Bas Ventín, Leticia | de Souza Troncoso, Jesús | Villasante, Sebastián
This paper investigates the ecological, social and institutional dimensions of the synergies and trade-offs between seagrasses and human activities operating in the Natura 2000 protected site of San Simón Bay (Galicia, NW Spain). By means of a multidisciplinary approach that brings together the development of a biological inventory combined with participatory mapping processes we get key spatial and contextual understanding regarding how, where and why marine users interact with seagrasses and how seagrasses are considered in policy making. The results highlight the fisheries' reliance on seagrass meadows and the controversial links with shellfisheries. The study also reveals unresolved conflicts among those management plans that promote the protection of natural values and those responsible for the exploitation of marine resources. We conclude that the adoption of pre-planning bottom-up participatory processes is crucial for the design of realistic strategies where both seagrasses and human activities were considered as a couple system.
اظهر المزيد [+] اقل [-]Development of current and future pollutant emissions for Portugal
2015
Sa, Elisa | Ferreira, Joana | Carvalho, Anabela | Borrego, C.
Air pollutant emissions are a fundamental input for accurate air quality simulations. Therefore, a detailed estimation of current emissions should be performed, mainly for the activity sectors that have higher contributions to emission totals. In order to estimate air quality under climate change at regional scale, it is extremely important to provide the most accurate emission inventories based on the emission scenarios used as input for the global climate models. The Representative Concentration Pathways (RCPs) are the most recent developed emission scenarios. Emission inventories used in air quality simulations at regional scale for future periods should be based on these recent developments. In this sense, an Emission Projections under RCP scenarios (EmiPro–RCP) model was developed to assist the estimation of future emission inventories for GHG and common air pollutants. This paper describes the methodology developed under EmiPro–RCP model and presents the estimation of current and projected emissions for Portugal for CO, PM2.5, PM10, SOx, NOx, NMVOC and NH3, which will be used as input in air quality modeling systems. A comparison between the inventories was performed and the results indicated that all the RCPs scenarios predict a decrease in most of the air pollutant emissions until 2100, with the exception of NH3 that increases. The main decreases are found in the coastal zone of Portugal, mainly in Porto and Lisbon urban areas, while the NH3 increases are located not only in the coastal zone but also in the southern inland of Portugal.
اظهر المزيد [+] اقل [-]Oil spill hazard from dispersal of oil along shipping lanes in the Southern Adriatic and Northern Ionian Seas
2015
Liubartseva, S. | De Dominicis, M. | Oddo, P. | Coppini, G. | Pinardi, N. | Greggio, N.
An assessment of hazard stemming from operational oil ship discharges in the Southern Adriatic and Northern Ionian (SANI) Seas is presented. The methodology integrates ship traffic data, the fate and transport oil spill model MEDSLIK-II, coupled with the Mediterranean Forecasting System (MFS) ocean currents, sea surface temperature analyses and ECMWF surface winds. Monthly and climatological hazard maps were calculated for February 2009 through April 2013. Monthly hazard distributions of oil show that the zones of highest sea surface hazard are located in the southwestern Adriatic Sea and eastern Ionian Sea. Distinctive “hot spots” appear in front of the Taranto Port and the sea area between Corfu Island and the Greek coastlines. Beached oil hazard maps indicate the highest values in the Taranto Port area, on the eastern Greek coastline, as well as in the Bari Port area and near Brindisi Port area.
اظهر المزيد [+] اقل [-]Occurence and antimicrobial resistance of Staphylococcus aureus and Salmonella spp. in retail fish samples in Turkey
2015
Ertas Onmaz, Nurhan | Abay, Secil | Karadal, Fulden | Hizlisoy, Harun | Telli, Nihat | Al, Serhat
The aims of this study were to investigate the presence of Staphylococcus aureus and staphylococcal enterotoxins, as well as Salmonella spp. and to determine the antimicrobial susceptibilities of the isolates from fish samples. A total of 100 fish samples were analysed consisting of 30 anchovy, 35 trout and 35 sea bream. The presence of SEs was detected using ELISA and its genes confirmed by mPCR. Also, S. aureus and Salmonella spp. were detected in 9 (9%) and 5 (5%) samples, respectively. None of the S. aureus isolates had SEs and SEs genes. The resistance rates of the S. aureus isolates to erythromycin, tetracycline, and penicillin G were found to be 33% while Salmonella spp. isolates were resistant to trimethoprim-sulfamethoxazole, gentamicin and neomycine in 20%, 20% and 80%, respectively of the samples. It is of utmost important for public health that retail fish markets need to use hygienic practices in handling and processing operations.
اظهر المزيد [+] اقل [-]A new approach to the prediction of PM10 concentrations in Central Anatolia Region, Turkey
2015
Ozel, Gamze | Cakmakyapan, Selen
Environmental pollution control is one of the most important goals in pollution risk assessment. In this sense, modern and precise tools that allow scientists to quantify and predict air pollution are of particular interest. In this study, we describe an air quality evaluation in terms of particulate matter having a diameter < 10μm (PM10), using a gamma–Poisson process. PM10 measurements from 2007 to 2013 at 24 air quality monitoring stations of Ministry of Environment and Urbanization (Turkey), was used to predict air pollution levels in Central Anatolia Region of Turkey. We assume that the number of PM10 peaks follows a Poisson process and PM10 amount of each peak fits a gamma distribution. The findings indicate that daily average of number for the threshold exceedance of PM10 concentration is 1.3 for all monitoring stations. The probability of exceedance the PM10 concentration threshold once a day is 0.35 for all monitoring stations. The results also show that the probabilities of total PM10 concentrations exceeding threshold are rapidly decreasing after 158μg/m3 which will occur in one day. The average of daily total PM10 concentration is 148μg/m3, the average of monthly total PM10 concentration is 4 437μg/m3, and the average of yearly total PM10 concentrations is 53 984μg/m3. It is found that there is a moderate correlation between the number of threshold exceedances and the total PM10 concentrations in Central Anatolia Region. Thus, it was concluded that gamma–Poisson process could be promising for air pollutant prediction for a given period of time.
اظهر المزيد [+] اقل [-]The emerging threats of climate change on tropical coastal ecosystem services, public health, local economies and livelihood sustainability of small islands: Cumulative impacts and synergies
2015
Hernández-Delgado, E.A.
Climate change has significantly impacted tropical ecosystems critical for sustaining local economies and community livelihoods at global scales. Coastal ecosystems have largely declined, threatening the principal source of protein, building materials, tourism-based revenue, and the first line of defense against storm swells and sea level rise (SLR) for small tropical islands. Climate change has also impacted public health (i.e., altered distribution and increased prevalence of allergies, water-borne, and vector-borne diseases). Rapid human population growth has exacerbated pressure over coupled social–ecological systems, with concomitant non-sustainable impacts on natural resources, water availability, food security and sovereignty, public health, and quality of life, which should increase vulnerability and erode adaptation and mitigation capacity. This paper examines cumulative and synergistic impacts of climate change in the challenging context of highly vulnerable small tropical islands. Multiple adaptive strategies of coupled social–ecological ecosystems are discussed. Multi-level, multi-sectorial responses are necessary for adaptation to be successful.
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