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Resultados 1021-1030 de 3,991
Application of novel image base estimation of invisible leaf injuries in relation to morphological and photosynthetic changes of Phaseolus vulgaris L. exposed to tropospheric ozone
2016
Drapikowska, M. | Drapikowski, P. | Borowiak, K. | Hayes, F. | Harmens, H. | Dziewiątka, T. | Byczkowska, K.
This study aimed to evaluate the degree of Phaseolus vulgaris L. (bean) leaf tissue injury caused by tropospheric ozone. To validate O3 symptoms at the microscopic level, Evans blue staining together with an image processing method for the removal of distortions and calculation of dead leaf areas was applied. Net photosynthetic rate (PN), stomatal conductance (gs) and intercellular CO2 concentration (Ci) were determined to evaluate leaf physiological responses to ozone. It was found that both resistant and sensitive varieties of bean were damaged by ozone; however, the size of necrotic and partially destroyed leaf area in the sensitive genotype (S156) was bigger (1.18%, 2.18%) than in the resistant genotype (R123), i.e. 0.02% and 0.50%. Values of net photosynthetic rates were lower in the sensitive genotype in ambient air conditions, than in the resistant genotype in ambient air conditions. We further found that there was a correlation between physiological and anatomical injuries; net photosynthetic rate (PN) was negatively correlated with percentage of necrotic area of both genotypes, while stomatal conductance (gs), intercellular CO2 concentration (Ci) were positively correlated with percentage of necrotic tissue of both genotypes. Moreover, visible injures in both genotypes were positively correlated with percentage of anatomical injures. In conclusion, the presented combinations of morphological, anatomical and physiological markers allowed differential diagnosis of ozone injury.
Mostrar más [+] Menos [-]Occurrence, spatial deposition and footprint of polybrominated diphenyl ethers in surficial sediments of Bushehr peninsula, the Persian Gulf
2016
Aghadadashi, Vahid | Mehdinia, Ali
The concentrations of polybrominated diphenyl ethers (PBDEs) were determined in the surficial sediments of Bushehr coasts, the Persian Gulf. Eighteen samples were collected from 6 sites at distances of 500, 1000 and 1500m from the coast. PBDEs were detected in all the samples, indicating their widespread occurrence in marine sediments of the studied area. BDE-209 and ∑7PBDEs were in the range of n.d. (not detected) to 6.29ngg−1 and n.d. to 0.62ngg−1 dw, respectively. The studied area can be classified as the region with the minimal contamination values reported globally as yet. The concentrations of PBDEs were lower than the Canadian benchmarks, and risk quotient assessments demonstrated low ecological risk. BDE-183 and then BDE-153 were the congeners with the highest detection frequencies in the stations, confirming extensive occurrence of Octa-mix in the studied area.
Mostrar más [+] Menos [-]Distribution and contamination of heavy metals in surface sediments of the Daya Bay and adjacent shelf, China
2016
Zhao, Guangming | Ye, Siyuan | Yuan, Hongming | Ding, Xigui | Wang, Jin
Heavy metal (arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), and zinc (Zn)) concentrations from the Daya Bay and adjacent shelf were determined to evaluate their levels and spatial distributions. The measured concentrations ranged from 1.94–13.67mg/kg for As, 0.03–0.13mg/kg for Cd, 10–85mg/kg for Cr, 1–39.5mg/kg for Cu, 0.01–0.09mg/kg for Hg, 11–56mg/kg for Pb, and 13–125mg/kg for Zn. The spatial distributions exhibited a gradual decrease from west to east, and the concentrations of the seven heavy metals met the China Marine Sediment Quality criteria. Both metal enrichment factor (EF) and geo-accumulation index (Igeo) values showed that Cd, Cr, Cu, Hg, and Zn were not at pollution levels in the region. Multivariate analysis (PCA) revealed that lithogenic factors dominated the distribution of most of the metals, whereas As and Hg were clearly influenced by anthropogenic input.
Mostrar más [+] Menos [-]Anthropogenic microfibres pollution in marine biota. A new and simple methodology to minimize airborne contamination
2016
Torre, Michele | Digka, Nikoletta | Anastasopoulou, Aikaterini | Tsangaris, Catherine | Mytilineou, Chryssi
Research studies on the effects of microlitter on marine biota have become more and more frequent the last few years. However, there is strong evidence that scientific results based on microlitter analyses can be biased by contamination from air transported fibres. This study demonstrates a low cost and easy to apply methodology to minimize the background contamination and thus to increase results validity. The contamination during the gastrointestinal content analysis of 400 fishes was tested for several sample processing steps of high risk airborne contamination (e.g. dissection, stereomicroscopic analysis, and chemical digestion treatment for microlitter extraction). It was demonstrated that, using our methodology based on hermetic enclosure devices, isolating the working areas during the various processing steps, airborne contamination reduced by 95.3%. The simplicity and low cost of this methodology provide the benefit that it could be applied not only to laboratory but also to field or on board work.
Mostrar más [+] Menos [-]Assessing of surface-ozone concentration in Bucharest, Romania, using OML and satellite data
2016
Grigoraş, Georgiana | Ştefan, Sabina | Rada, Constantin | Grigoraş, Cristinel
The aim of the paper is to assess the spatial distribution of surface-ozone concentrations for Bucharest urban agglomeration by running OML (“Operationelle Meteorologiske Luftkvalitetsmodeller” – Operational Meteorological Air Quality Model) dispersion model. Two data sets from 2009 were used to initialize the model for: (i) air quality data base of the National Network of Air Quality Monitoring (NNAQM); (ii) satellite data obtained from OMI (Ozone Monitoring Instrument) on board of AURA satellite. The potential of satellite data used in air quality assessment in lower troposphere, at local scale was also tested by comparison to data from air-quality monitoring stations. The intercomparison of simulated and measured data emphasized that satellite data can be used for assessment of air quality.
Mostrar más [+] Menos [-]Dynamics of δ15N isotopic signatures of different intertidal macroalgal species: Assessment of bioindicators of N sources in coastal areas
2016
Lemesle, Stéphanie | Erraud, Alexandre | Mussio, Isabelle | Rusig, Anne-Marie | Claquin, Pascal
δ15N of annual (Ulva sp., Porphyra sp.) and perennial intertidal seaweed species (Chondrus crispus, Fucus sp.) collected on 17 sampling points along the French coast of the English Channel in 2012 and 2013 were assessed on their suitability as bioindicators of N pollution in coastal areas. A sine function applied for δ15N time series data showed for all the species the same seasonal trend with lowest δ15N values in April and highest in summer but with no significant interspecific differences of amplitude (α) and phase angle (ϕ). This model provides a useful tool for monitoring the inter-annual changes of N pollution. An interspecific variability of δ15N values was observed, probably due to their tolerance to emersion. An in vitro study for comparing the kinetic acquisition of the isotopic signal and N uptake mechanisms of each species underlined the influence of algal physiology on the δ15N interspecific variability.
Mostrar más [+] Menos [-]A comparative proteomic study on the effects of metal pollution in oysters Crassostrea hongkongensis
2016
The metal pollution has posed great risk on the coastal organisms along the Jiulongjiang Estuary in South China. In this work, two-dimensional electrophoresis-based proteomics was applied to the oysters Crassostrea hongkongensis from metal pollution sites to characterize the proteomic responses to metal pollution. Metal accumulation and proteomic responses indicated that the oysters from BJ site were more severely contaminated than those from FG site. Compared with those oyster samples from the clean site (JZ), metal pollution induced cellular injuries, oxidative and immune stresses in oyster heapatopancreas from both BJ and FG sites via differential metabolic pathways. In addition, metal pollution in BJ site induced disturbance in energy and lipid metabolisms in oysters. Results indicated that cathepsin L and ferritin GF1 might be the biomarkers of As and Fe in oyster C. hongkongensis, respectively. This study demonstrates that proteomics is a useful tool for investigating biological effects induced by metal pollution.
Mostrar más [+] Menos [-]Health effects of air pollution: An empirical analysis for developing countries
2016
Fotourehchi, Zahra
In this research, we examine the effects of PM10 and CO2 air pollutants on infant mortality and life expectancy at birth, in 60 developing countries during the period 1990–2010 by using unbalanced panel data and recursive simultaneous equations model. Our results show that the gains are obtained in the health status through the improvement in socio-economic conditions can be canceled by PM10 and CO2 air pollutants. Therefore, health policies which just focus on socio-economic aspects and ignore the adverse impacts of the air pollution may do little in efforts directed to improve the current health status of developing countries.
Mostrar más [+] Menos [-]Prioritization maps: The integration of environmental risks to manage water quality in harbor areas
2016
Valdor, Paloma F. | Gómez, Aina G. | Ondiviela, Bárbara | Puente, Araceli | Juanes, J. A. (José A.)
A method to integrate the environmental risk of the multiple effects from uses and activities developed in harbor areas is presented. Consequences are considered as the effects derived from all identified hazards. Vulnerability is expressed in terms of functional relations between environmental susceptibility against a disturbance and the state of protection of the receptors at risk. Consequences and vulnerability are integrated obtaining a spatial variation of risk: prioritization maps. The maps are developed by 4 main stages: (1) environmental hazard identification; (2) estimation of the consequences; (3) estimation of vulnerability and, (4) integration of environmental risks. To adapt prioritization maps to the peculiarities of the study area, three different methods for the integration of the effects are proposed: average-value, worst-case and weighted methods. The implementation to a real case (Tarragona harbor, NE Spain) confirms its usefulness as a risk analysis tool to communicate and support water quality management in harbors.
Mostrar más [+] Menos [-]Transcription of a novel P450 gene varies with some factors (pollutant exposure, temperature, time, and body region) in a marine oligochaete (Thalassodrilides sp.)
2016
Cytochrome P450 (CYP) enzymes play important roles in the metabolism of exogenous compounds such as polycyclic aromatic hydrocarbons (PAHs). A novel, full-length CYP gene (CYP4V30) was identified in the oligochaete Thalassodrilides sp. CYP4V30 mRNA expression was studied in worms exposed to PAH-polluted (Σ16PAHs; 37441ng/g dry weight) or unpolluted (Σ16PAHs; 19ng/g dry weight) sediment. CYP4V30 expression was much higher in worms exposed to contaminated sediments than in those exposed to unpolluted sediments at some temperatures (20 and 25°C) and exposure durations (11-fold increase at 20°C, 10-day exposure), but not at 15°C or other exposure durations (P<0.05). CYP4V30 mRNA expression was higher in the middle of the body than in the posterior (P<0.05). The variation in transcriptional response with exposure time, temperature, and body region indicates that these factors should be considered when monitoring marine sediment pollution.
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