خيارات البحث
النتائج 1651 - 1660 من 4,033
Corticosterone stress hormone responses in oil rehabilitated and non-rehabilitated little penguins
2016
Chilvers, B.L. | Finlayson, G. | Candy, E.J. | Sriram, A. | Morgan, K.J. | Cockrem, J.F.
Whether oiled wildlife should be rehabilitated during an oil spill is internationally debated. Research on little penguins (LP, Eudyptula minor) rehabilitated and released back into a cleaned environment after the New Zealand C/V Rena grounding oil spill in 2011 found the rehabilitation process was effective at treating and reversing the negative effects of oil-contamination on penguin post-release survival, productivity and diving behaviour. Here we investigated the acute corticosterone stress response of LPs to determine if responses of rehabilitated birds differed from those of “control” birds. Corticosterone responses of LPs two years after an oil spill did not differ between rehabilitated and non-rehabilitated penguins. These results show that the rehabilitation process for LP did not affect their long-term physiological responses to humans. This indicates that wildlife can be rehabilitated and returned to the wild with similar human tolerance levels to non-rehabilitated birds and an absence of habituation.
اظهر المزيد [+] اقل [-]First comprehensive screening of lipophilic organic contaminants in surface waters of the megacity Jakarta, Indonesia
2016
Dsikowitzky, L. | Sträter, M. | Dwiyitno, | Ariyani, F. | Irianto, H.E. | Schwarzbauer, J.
Jakarta is an Indonesian coastal megacity with over 10 million inhabitants. The rivers flowing through the city receive enormous amounts of untreated wastewaters and discharge their pollutant loads into Jakarta Bay. We utilized a screening approach to identify those site-specific compounds that represent the major contamination of the cities' water resources, and detected a total number of 71 organic contaminants in Jakarta river water samples. Especially contaminants originating from municipal wastewater discharges were detected in high concentrations, including flame retardants, personal care products and pharmaceutical drugs.A flame retardant, a synthetic fragrance and caffeine were used as marker compounds to trace the riverine transport of municipal wastewaters into Jakarta Bay. These markers are also appropriate to trace municipal wastewater discharges to other tropical coastal ecosystems. This application is in particular useful to evaluate wastewater inputs from land-based sources to habitats which are sensitive to changing water quality, like coral reefs.
اظهر المزيد [+] اقل [-]Assessment of the impact of emissions reductions on air quality over North China Plain
2016
Han, Xiao | Zhang, Meigen | Zhu, Lingyun | Skorokhod, Andrei
The production rate of secondary pollutants was highly non-linear with the emission intensity of their precursors. In this study, the air quality modeling system RAMS-CMAQ with zero-out sensitivity test was applied to conduct source sensitivity approaches of PM2.5 for four source categories (industry, power plants, transport, and residential) over the North China Plain (NCP) in January and July of 2013. The results show that the residential and industry emission sector were the greatest contributors to domain-wide PM2.5 in January and July, respectively. The largest variation could exceed 200 μg m−3 attributed to the residential sector in January when a heavy pollution period appeared, and could reach 40–60 μg m−3 attributed to the industry sector in July in the heavy pollution area, respectively. The nonlinear relationship between the secondary pollutant formation and its precursors was reflected by this source sensitivity approaches, as the summation of the secondary pollutant variations attributed to the four sources was obviously different from the simulated baseline concentration and the mass burden of nitrate would increase upon removal of the power plants or transport emission sector in the heavy pollution regions in January. Further analysis indicated that the improvement of atmospheric oxidation capacity due to emission sector removal coupled with the sufficient precursor nitrogen oxide under severe pollution background should be the main reason of the negative variation of nitrate appeared in the sensitivity test. This feature indicates that the atmospheric oxidation capacity is an important impact factor in determining the production rate of nitrate formation, and could further influence the variation feature of PM2.5 mass burden during the pollution episode. Thus, it is suggested that the comprehensive pollution control strategies should be implemented based on the specific pollution condition. Additionally, the nonlinearity of secondary pollutants formation should be reasonably considered for developing effective emission control strategies.
اظهر المزيد [+] اقل [-]Investigating ozone high levels and the role of sea breeze on its transport
2016
Monteiro, Alexandra | Gama, Carla | Cândido, Marta | Ribeiro, Isabel | Carvalho, David | Lopes, Myriam
This works intends to investigate the ozone episodes reported in three different monitoring sites distributed along the Central region of Portugal (from the coast to inland direction). Ozone data time series are first analysed according to the legislation thresholds fulfilment (information threshold and target value) and two episodes are selected according to the magnitude and simultaneously exceedances at the three sites. The episodes are then analysed in terms of meteorological data (surface and vertical profiles) obtained with the WRF model and also using backtrajectories obtained with the HYSPLIT model. The integration of both results, together with the ozone and NO2 precursor concentration time series, allowed to conclude about the different origin of ozone in the two episodes. A sea breeze circulation is present in the first episode, inducing the transport of this pollutant and its precursors from the coast to inland (about 30 km), which is verified by the wind patterns and vertical profiles and by the daily profile of O3 measured at the three sites. The second episode studied does not show so clearly this influence.
اظهر المزيد [+] اقل [-]A novel methodology for the determination of biomarker baseline levels in the marine polychaete Hediste diversicolor
2016
Barrick, A. | Châtel, A. | Marion, J.-M. | Perrein-Ettajani, H. | Bruneau, M. | Mouneyrac, C.
Identifying environmental damage due to anthropogenic activities is a focal point for scientists and policy makers like those involved in the European Water Framework Directive (WFD). Many of these approaches focus on ecological endpoints for assessing environmental perturbations, which lead to policies emphasizing mitigation rather than prevention. Biomarkers provide early-warning indicators of stress but it is necessary to distinguish their natural variations from those induced by chemical stress. The global aim of this study was to establish a baseline assessment criterion (BAC) using historical data in a reference site to define toxicity thresholds. We have developed a multiple polynomial regression model (MPR) accounting the influence of salinity, temperature and size of individual on energetic reserves (glycogen and lipids) in the marine polychaete Hediste diversicolor. The model identified a complex, orthogonal relationship between confounding factors and glycogen and a linear relationship between lipids and size of individuals.
اظهر المزيد [+] اقل [-]Biases and best approaches for assessing debris ingestion in sea turtles, with a case study in the Mediterranean
2016
Casale, Paolo | Freggi, Daniela | Paduano, Valentina | Oliverio, Marco
In a sample of 567 loggerhead turtles (Caretta caretta) from the central Mediterranean, debris occurrence varied according to methods and turtle source, and was up to 80% in pelagic turtles. Frequencies of plastic types, size and color are also reported. These results and a critical review of 49 studies worldwide indicate that: (i) the detected occurrence of plastic (% turtles) is affected by several factors (e.g., necropsy/feces, ecological zone, type and date of finding, captivity period for feces collection), (ii) mixed dataset and opportunistic approaches provide results which are biased , not comparable, and ultimately of questionable value, (iii) only turtles assumed to have had a normal feeding behaviour at the time of capture or death should be considered, (iv) turtle foraging ecology and possible selectivity may undermine the use of turtles as indicator species for monitoring marine litter, as recently proposed for the Mediterranean.
اظهر المزيد [+] اقل [-]Variation in characteristics of air concentrations of NH3, NO2 and O3 induced by applications of urea in soils of plastic greenhouses in suburban China
2016
Jiang, Zhaohui | Zeng, Qingru | Pi, Hejie | Tie, Baiqing
Few studies have been carried out so far for measuring concentrations of NH3, NO2 and O3 in plastic greenhouses. In this study, NH3, NO2 and O3 concentrations were measured with passive sampler technology in a plastic greenhouse located in the Changsha suburb in southern China over a one and a half month period (November 30, 2008 to January 11, 2009). Soil in the greenhouse was subjected to four treatment (T) types (no N fertilizer T1, common urea T2, coated urea T3 and common urea with nitrification inhibitor dicyandiamide (DCD) T4. The average concentrations (μg/m3) of NH3, NO2 and O3 in descending order was: T4 (31.66) > T2 (25.93) > T3 (23.52) > T1 (7.96), T2 (10.99) > T3 (8.16) > T4 (7.48) > T1 (5.20), T2 (75.05) > T3 (64.20) > T4 (63.85) > T1 (49.02), respectively. This implied that photochemical reactions took place and that harmful gases accumulated after application of N fertilizer in the plastic greenhouse. DCD inhibited the conversion of ammonium to nitrate, increased NH3 volatilization and decreased NO2 level. The coated urea decreased the emissions of NH3 and increased nitrogen use efficiency. We found significant positive correlations (p < 0.01) between temperature and both NH3 and NO2 levels. Correlations between soil pH and both NH3 and NO2 concentrations were also significant (p < 0.01). The O3 average concentration from March 31, 2009 to April 10, 2009 in the higher latitude of the Yinchuan suburb in northern China was two times greater than that in the Changsha suburb in southern China. The O3 daily concentrations in the Yinchuan suburb exceeded 160 μg/m3 (i.e., China's Grade I standard), and the maximal value 214.83 μg/m3 exceeded 200 μg/m3 (i.e., China's Grade III standard).
اظهر المزيد [+] اقل [-]The phenomena of spreading ambient ozone at the west coast air basin of Taiwan
2016
Liang, Chen-Jui | Xue, Yang-Shen | Liang, Jeng-Jong
The total air pollution model (TAPM, www.cmar.csiro.au/research/tapm) was used to explore the phenomena of spreading ambient ozone in the complex 196 km × 196 km terrain of the west coast air basin of Taiwan (including ocean area). The altitude in the air basin ranges from 0 m (sea level) to 3000+ m (high mountain). The data of 2010–2014 from 21 air-quality monitoring stations were used to ensure the accuracy of the simulation results in accordance with an average index of agreement (IOA) > 0.61. Four ozone-spreading phenomena were observed among the air basin: the north–south spreading on the offshore (N–S SOO), north–south spreading around the coast (N–S SAC), east–west spreading from the ocean (E–W SFO), and east–west spreading around the mountain front (E–W SAMF). The results indicate that when two prevailing flows meet and interact at their boundaries, they form a convergence zone. The convergence zone presents distinctive weather conditions and accumulates air pollutants. More than wind direction, the ozone concentration is dependent on the topography and surrounding conditions. The results clearly show that the ozone-spreading phenomena follow certain rules. The N–S SOO, N–S SAC, E–W SFO, and E–W SAMF phenomena are during the northeaster, fore-southwester, southwester, and fore-northeaster monsoon months, respectively. Wind fields are a major factor in the high concentration of ozone and ozone spreading, especially downdraft and onshore winds. The diversion of river valleys and the mountainous barrier between the basin/hill and mountains exert obvious influences on the local wind field, strongly affecting the ozone-spreading phenomena.
اظهر المزيد [+] اقل [-]The invasive lionfish, Pterois volitans, used as a sentinel species to assess the organochlorine pollution by chlordecone in Guadeloupe (Lesser Antilles)
2016
Charlotte, Dromard R. | Yolande, Bouchon-Navaro | Cordonnier, Sebastien | Claude, Bouchon
In Guadeloupe, many marine organisms are affected by an organochlorine pollution used in the past by the banana industry to fight against the banana weevil. In the present study, we evaluated the level of contamination of the invasive Indo-Pacific lionfish, Pterois volitans, all around the island. Concentrations of chlordecone varied from 3 to 144μg.kg−1 wet weight. The highest concentrations were recorded when samples were captured in the marine zones located downstream of the previous banana plantations. This contamination seemed to decrease rapidly with the distance from the coast. Mean concentration of chlordecone in Pterois volitans was higher than that of five other fish species collected in similar sites. Due to its position at the top of the trophic web, lionfish was affected by bioaccumulation of chlordecone and can be used as a sentinel species to assess and control the level of contamination of the marine environment by chlordecone.
اظهر المزيد [+] اقل [-]Heavy metal accumulation in tissues of two sea cucumbers, Holothuria leucospilota and Holothuria scabra in the northern part of Qeshm Island, Persian Gulf
2016
Mohammadizadeh, Maria | Bastami, Kazem Darvish | Ehsanpour, Maryam | Afkhami, Majid | Mohammadizadeh, Flora | Esmaeilzadeh, Marjan
The concentrations of some heavy metals (Cd, Cu, Zn andPb) were investigated in the sediments and the two species of sea cucumber (Holothuria leucospilota and Holothuria scabra) from northern part of Qeshm Island, Persian Gulf. The levels of Cu, Zn and Pb in sediment varied significantly among sampling sites (p<0.05). The highest levels of Zn and Pb in H. leucospilota were recorded in body wall whereas the highest contents of Zn and Pb in H. scabra were measured in respiratory tree organ, respectively. Cu and Cd were the most abundant elements in gonads of H. leucospilota while highest levels of Cd and Cu in H. scabra were measured in the gonad and derm, respectively. Cu and Zn concentrations were below permissible limits for human consumption while Cd and Pb were above permissible limits for human consumption.
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