خيارات البحث
النتائج 511 - 520 من 2,512
Monitoring plant response to phenanthrene using the red edge of canopy hyperspectral reflectance النص الكامل
2014
Zhu, Linhai | Chen, Zhongxin | Wang, Jianjian | Ding, Jinzhi | Yu, Yunjiang | Li, Junsheng | Xiao, Nengwen | Jiang, Lianhe | Zheng, Yuanrun | Rimmington, Glyn M.
To investigate the mechanisms and potential for the remote sensing of phenanthrene-induced vegetation stress, we measured field canopy spectra, and associated plant and soil parameters in the field controlled experiment in the Yellow River Delta of China. Two widely distributed plant communities, separately dominated by reed (Phragmites australis) and glaucous seepweed (Suaeda salsa), were treated with different doses of phenanthrene. The canopy spectral changes of plant community resulted from the decreases of biomass and foliar projective coverage, while leaf photosynthetic pigment concentrations showed no significance difference among treatments. The spectral response to phenanthrene included a flattened red edge, with decreased first derivative of reflectance. The red edge slope and area consistently responded to phenanthrene, showing a strong relationship with aboveground biomass, coverage and canopy pigments density. These results suggest the potential of remote sensing and the importance of field validation to correctly interpret the causes of the spectral changes.
اظهر المزيد [+] اقل [-]Distribution and transfer pattern of Polychlorinated Biphenyls (PCBs) among the selected environmental media of Ny-Ålesund, the Arctic: As a case study النص الكامل
2014
Zhang, Peng | Ge, Linke | Gao, Hui | Yao, Ting | Fang, Xiaodan | Zhou, Chuanguang | Na, Guangshui
Polychlorinated Biphenyls (PCBs) were analyzed in multi-environmental samples collected from Ny-Ålesund, the Arctic to explore their legacy and transfer patterns. PCBs were ubiquitously in the environmental media, within the ranges of 1.73–6.27 and 9.18–141.1pgm−3 in vapor and aerosol, 2.76–10.8, 3.09–8.32, 22.5–56.3, 35.4–51.4 and 31.8–39.6ngg−1 (dry weight) in soil, sediment, plant, bird guano and reindeer faeces, respectively. The spatial distribution patterns exhibited a general southward decline in soil and sediment from the bay entrance to the inner bay. The concentration ratios of plants to soil inferred that no distinguished selective adsorption of PCBs congeners by plants existed and PCBs were mainly attributed to the air deposition on plant surface. The fugacity ratios among vapor, aerosol and soil indicted that the equilibrium status has not been reached and the net transferring direction was air–soil.
اظهر المزيد [+] اقل [-]Macrobenthic diversity in protected, disturbed, and newly formed intertidal wetlands of a subtropical estuary in China النص الكامل
2014
Lv, Weiwei | Ma, Chang-an | Huang, Youhui | Yang, Yang | Yu, Ji | Zhang, Mingqing | Zhao, Yunlong
In this study, intertidal macrobenthic diversity in protected, disturbed, and newly formed wetlands of Yangtze estuary was assessed using PRIMER 5.2 based on species diversity and species relatedness. We observed high diversity in nature reserves and low diversity in adjacent disturbed and newly formed wetlands. These diversity data were then integrated with historical data to detect the variation in macrobenthic diversity over the past two decades. The integrated data indicated that the intertidal macrobenthic diversity sharply decreased in heavy reclamation tidal flats whereas markedly increased in non-disturbed nature reserve and newly formed wetland. Benthic health was observed with the departure degree of average taxonomic distinctness (Δ+) and variation in taxonomic distinctness (Λ+) from the simulated 95% confidence funnel. All the habitats were subjected to different levels of human interference, except Jiuduansha and Beigangbeisha. The degradation of intertidal wetland in Yangtze estuary was mainly attributed to land reclamation, overgrazing, and overfishing.
اظهر المزيد [+] اقل [-]Review of oil spill remote sensing النص الكامل
2014
Fingas, Mervin F. | Brown, Carl
Remote-sensing for oil spills is reviewed. The use of visible techniques is ubiquitous, however it gives only the same results as visual monitoring. Oil has no particular spectral features that would allow for identification among the many possible background interferences. Cameras are only useful to provide documentation. In daytime oil absorbs light and remits this as thermal energy at temperatures 3–8K above ambient, this is detectable by infrared (IR) cameras.Laser fluorosensors are useful instruments because of their unique capability to identify oil on backgrounds that include water, soil, weeds, ice and snow. They are the only sensor that can positively discriminate oil on most backgrounds. Radar detects oil on water by the fact that oil will dampen water-surface capillary waves under low to moderate wave/wind conditions. Radar offers the only potential for large area searches, day/night and foul weather remote sensing.
اظهر المزيد [+] اقل [-]Geochemical characteristics of phosphorus in surface sediments of two major Chinese mariculture areas: The Laizhou Bay and the coastal waters of the Zhangzi Island النص الكامل
2014
Zhuang, Wen | Gao, Xuelu | Zhang, Yong | Xing, Qianguo | Tosi, Luigi | Qin, Song
Phosphorus (P) in surface sediments of the Laizhou Bay (LB) and the coastal waters around the Zhangzi Island (ZI) was analyzed. Six forms of P were separated — exchangeable or loosely sorbed P (Ads–P), aluminum-bound P (Al–P), iron-bound P (Fe–P), authigenic apatite plus CaCO3-bound P plus biogenic apatite (Ca–P), detrital apatite plus other inorganic P (De–P) and organic P (OP). The average contents of P in the LB were in the order: De–P>OP>Ca–P>Fe–P>Ads–P>Al–P; in the ZI, the corresponding order was De–P>OP>Fe–P>Ca–P>Ads–P>Al–P. Due to the high nutrient loadings from the surrounding rivers, TP contents in sediments of the LB were higher than in those of the ZI. The potential bio-available P (Ads–P and OP) accounted for 14.7% and 24.2% of TP in sediments of the LB and the ZI, respectively.
اظهر المزيد [+] اقل [-]Impacts of Macondo oil from Deepwater Horizon spill on the growth response of the common reed Phragmites australis: A mesocosm study النص الكامل
2014
Judy, Chad R. | Graham, Sean A. | Lin, Qianxin | Hou, Aixin | Mendelssohn, I. A.
We investigated impacts of Macondo MC252 oil from the Deepwater Horizon (DWH) spill on the common reed Phragmites australis (Cav.) Trin. ex Steud., a dominant species of the Mississippi River Delta. In greenhouse experiments, we simulated the most common DWH oiling scenarios by applying weathered and emulsified Macondo oil to aboveground shoots at varying degrees of coverage (0–100%) or directly to marsh soil at different dosages (0–16Lm−2). P. australis exhibited strong resistance to negative impacts when oil was applied to shoots alone, while reductions in above- and belowground plant growth were apparent when oil was applied to the soil or with repeated shoot-oiling. Although soil-oiling compromised plant function, mortality of P. australis did not occur. Our results demonstrate that P. australis has a high tolerance to weathered and emulsified Macondo oil, and that mode of exposure (aboveground versus belowground) was a primary determinant of impact severity.
اظهر المزيد [+] اقل [-]Assessment of the abiotic and biotic effects of sodium metabisulphite pulses discharged from desalination plant chemical treatments on seagrass (Cymodocea nodosa) habitats in the Canary Islands النص الكامل
2014
Portillo, E. | Ruiz de la Rosa, M. | Louzara, G. | Ruiz, J.M. | Marín-Guirao, L. | Quesada, J. | González, J.C. | Roque, F. | González, N. | Mendoza, H.
Assessment of the abiotic and biotic effects of sodium metabisulphite pulses discharged from desalination plant chemical treatments on seagrass (Cymodocea nodosa) habitats in the Canary Islands النص الكامل
2014
Portillo, E. | Ruiz de la Rosa, M. | Louzara, G. | Ruiz, J.M. | Marín-Guirao, L. | Quesada, J. | González, J.C. | Roque, F. | González, N. | Mendoza, H.
Reverse osmosis membranes at many desalination plants are disinfected by periodic shock treatments with sodium metabisulphite, which have potentially toxic effects to the environment for marine life, although no empirical and experimental evidence for this is yet available. The aim of this study was to characterise for the first time, the physico-chemical modification of the marine environment and its biological effects, caused by hypersaline plumes during these membrane cleaning treatments. The case study was the Maspalomas II desalination plant, located in the south of Gran Canaria (Canary Islands, Spain). Toxicity bioassays were performed on marine species characteristic for the infralittoral soft bottoms influenced by the brine plume (Synodus synodus and Cymodocea nodosa), and revealed a high sensitivity to short-term exposure to low sodium metabisulphite concentrations. The corrective measure of incorporating a diffusion system with Venturi Eductors reduced nearly all the areas of influence, virtually eliminating the impact of the disinfectant.
اظهر المزيد [+] اقل [-]Assesment of the abiotic and biotic effects of sodium metabisulphite pulses discharged from desalination plant chemical treatments on seagrass (Cymodocea nodosa) habitats in the Canary Islands النص الكامل
2014
Portillo, Eduardo | Ruiz-de-la-Rosa, Manuel | Louzara, G. | Ruiz-Fernández, Juan Manuel | Marín-Guirao, Lázaro | Quesada, J. | González, J.C. | Roque, F. | González, N. | Mendoza, H.
Reverse osmosis membranes at many desalination plants are disinfected by periodic shock treatments with sodium metabisulphite, which have potentially toxic effects to the environment for marine life, although no empirical and experimental evidence for this is yet available. The aim of this study was to characterise for the first time, the physico-chemical modification of the marine environment and its biological effects, caused by hypersaline plumes during these membrane cleaning treatments. The case study was the Maspalomas II desalination plant, located in the south of Gran Canaria (Canary Islands, Spain). Toxicity bioassays were performed on marine species characteristic for the infralittoral soft bottoms influenced by the brine plume (Synodus synodus and Cymodocea nodosa), and revealed a high sensitivity to short-term exposure to low sodium metabisulphite concentrations. The corrective measure of incorporating a diffusion system with Venturi Eductors reduced nearly all the areas of influence, virtually eliminating the impact of the disinfectant. | This study was conducted as part of the Project “Technical feasibility study of Venturi Diffusers in desalination plant brine discharges to enhance the dilution process and reduce the environmental impact on marine ecosystems”, under the National Programme for Experimental Development Projects, within the Ministry of the Environment and Rural and Marine Affairs, Environment and Eco-Innovation Sector, Management and Sustainable Uses of Natural Resources Subsection. The authors would like to thank Canaragua-Aqualogy, Elmasa Tecnologia del Agua, CEDEX and ECOS for their support and assistance, A. Arencibia and F. Roch, from General Electrics, and J. McGrath for translation of the manuscript. This research was also funded by other two Projects granted by the Ministry of the Environment and Rural and Marine Affairs (OSMOGRASS Project no. 021/SGTB/2007/1.3) and the Science National Plan of the Ministry of Science and Innovation (OSMOGRASS II Project no. CTM2009-08413MAR) to J.M. Ruiz of the Spanish Oceanography Institute. | Peer reviewed
اظهر المزيد [+] اقل [-]A probabilistic model for accidental cargo oil outflow from product tankers in a ship–ship collision النص الكامل
2014
Goerlandt, Floris | Montewka, Jakub
In risk assessment of maritime transportation, estimation of accidental oil outflow from tankers is important for assessing environmental impacts. However, there typically is limited data concerning the specific structural design and tank arrangement of ships operating in a given area. Moreover, there is uncertainty about the accident scenarios potentially emerging from ship encounters. This paper proposes a Bayesian network (BN) model for reasoning under uncertainty for the assessment of accidental cargo oil outflow in a ship–ship collision where a product tanker is struck. The BN combines a model linking impact scenarios to damage extent with a model for estimating the tank layouts based on limited information regarding the ship. The methodology for constructing the model is presented and output for two accident scenarios is shown. The discussion elaborates on the issue of model validation, both in terms of the BN and in light of the adopted uncertainty/bias-based risk perspective.
اظهر المزيد [+] اقل [-]Evaluation of the levels of alcohol sulfates and ethoxysulfates in marine sediments near wastewater discharge points along the coast of Tenerife Island النص الكامل
2014
Fernández-Ramos, C. | Ballesteros, O. | Zafra-Gómez, A. | Camino-Sánchez, F.J. | Blanc, R. | Navalón, A. | Pérez-Trujillo, J.P. | Vílchez, J.L.
Alcohol sulfates (AS) and alcohol ethoxysulfates (AES) are all High Production Volume and ‘down-the-drain’ chemicals used globally in detergent and personal care products, resulting in low levels ultimately released to the environment via wastewater treatment plant effluents. They have a strong affinity for sorption to sediments. Almost 50% of Tenerife Island surface area is environmentally protected. Therefore, determination of concentration levels of AS/AES in marine sediments near wastewater discharge points along the coast of the Island is of interest. These data were obtained after pressurized liquid extraction and liquid chromatography–tandem mass spectrometry analysis. Short chains of AES and especially of AS dominated the homologue distribution for AES. The Principal Components Analysis was used. The results showed that the sources of AS and AES were the same and that both compounds exhibit similar behavior. Three different patterns in the distribution for homologues and ethoxymers were found.
اظهر المزيد [+] اقل [-]Biomarkers of endocrine disruption in juveniles and females of the estuarine fish Pomatoschistus microps النص الكامل
2014
Dias, Lídia C.A. | Soares, Amadeu M.V.M. | Ferreira, Abel L.G. | Santos, Cátia S. | Monteiro, Marta S.
Biomarkers of endocrine disruption in juveniles and females of the estuarine fish Pomatoschistus microps النص الكامل
2014
Dias, Lídia C.A. | Soares, Amadeu M.V.M. | Ferreira, Abel L.G. | Santos, Cátia S. | Monteiro, Marta S.
The presence of endocrine disruptor chemicals (EDCs) in aquatic compartments, including estuaries, has been object of major concern. However, the effects of EDCs on autochthonous estuarine fish species are far less known than in freshwater fish. Therefore, the response of biomarkers in the estuarine fish Pomatoschistus microps was evaluated after 21-days of exposure to different EDCs: 17β-estradiol (E2); PCB-77 and p,p′DDE. In juveniles, Vtg (vitellogenin)-like proteins were significantly induced by E2. PCB-77 led to a decrease of Vtg-like proteins in juveniles, while in female liver they increased at the highest concentrations tested, suggesting a mode of action of PCB-77 that depends on the fish life stage. p,p′-DDE did not induce significant changes in Vtg-like proteins. Overall, P. microps juveniles seemed to respond to environmental relevant concentrations of EDCs. Thus, the evaluation of Vtg-like proteins in this life stage seems to be a promising tool to track EDC contamination in biomonitoring studies.
اظهر المزيد [+] اقل [-]Biomarkers of endocrine disruption in juveniles and females of the estuarine fish Pomatoschistus microps النص الكامل
2014 | 1000
Dias, Lídia C. A. | Soares, Amadeu M. V. M. | Ferreira, Abel L. G. | Santos, Cátia S. | Monteiro, Marta S.
The presence of endocrine disruptor chemicals (EDCs) in aquatic compartments, including estuaries, has been object of major concern. However, the effects of EDCs on autochthonous estuarine fish species are far less known than in freshwater fish. Therefore, the response of biomarkers in the estuarine fish Pomatoschistus microps was evaluated after 21-days of exposure to different EDCs: 17β-estradiol (E2); PCB-77 and p,p'DDE. In juveniles, Vtg (vitellogenin)-like proteins were significantly induced by E2. PCB-77 led to a decrease of Vtg-like proteins in juveniles, while in female liver they increased at the highest concentrations tested, suggesting a mode of action of PCB-77 that depends on the fish life stage. p,p'-DDE did not induce significant changes in Vtg-like proteins. Overall, P. microps juveniles seemed to respond to environmental relevant concentrations of EDCs. Thus, the evaluation of Vtg-like proteins in this life stage seems to be a promising tool to track EDC contamination in biomonitoring studies.
اظهر المزيد [+] اقل [-]