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Resultados 1041-1050 de 3,189
Chemical comparison and acute toxicity of water accommodated fraction (WAF) of source and field collected Macondo oils from the Deepwater Horizon spill
2015
Faksness, Liv-Guri | Altin, Dag | Nordtug, Trond | Daling, Per S. | Hansen, Bjørn Henrik
Two Source oils and five field collected oil residues from the Deepwater Horizon incident were chemically characterized. Water accommodated fractions (WAFs) of the Source oils and two of the field-weathered oils were prepared to evaluate the impact of natural weathering on the chemical composition and the acute toxicity of the WAFs. Toxicity test species representing different tropic levels were used (the primary producer Skeletonema costatum (algae) and the herbivorous copepod Acartia tonsa). The results suggest that the potential for acute toxicity is higher in WAFs from non-weathered oils than WAFs from the field weathered oils. The Source oils contained a large fraction of soluble and bioavailable components (such as BTEX (benzene, toluene, ethyl benzene, xylenes) and naphthalene), whereas in the surface collected oils these components were depleted by dissolution into the water column as the oil rose to the surface and by evaporative loss after reaching the sea surface.
Mostrar más [+] Menos [-]Mussel farming in Maliakos Gulf and quality indicators of the marine environment: Good benthic below poor pelagic ecological status
2015
Dimitriou, Panagiotis D. | Karakassis, Ioannis | Pitta, Paraskevi | Tsagaraki, Tatiana Margo | Apostolaki, Eugenia T. | Magiopoulos, Iordanis | Nikolioudakis, Nikolaos | Diliberto, Santi | Theodorou, John A. | Tzovenis, Ioannis | Kagalou, Ifigenia | Beza, Paraskevi | Tsapakis, Manolis
Biological and geochemical variables in the water column and sediments were monitored along a transect of a mussel farm located in a transitional environment in Maliakos Gulf, a semi-enclosed gulf in eastern Mediterranean. Analyses of water, sediment and macrofauna samples were used to calculate ecological status indicators in the context of the European Water Framework Directive. The water column ecological status was “Poor” or “Bad” showing little change with distance from the farm, but the ecological status of the benthic communities was found to be “Good,” although there were quantitative changes in macrofaunal indices with distance from the farm.
Mostrar más [+] Menos [-]Microplastic in a macro filter feeder: Humpback whale Megaptera novaeangliae
2015
Besseling, E. | Foekema, E.M. | Van Franeker, J.A. | Leopold, M.F. | Kühn, S. | Bravo Rebolledo, E.L. | Heße, E. | Mielke, L. | IJzer, J. | Kamminga, P. | Koelmans, A.A.
Marine filter feeders are exposed to microplastic because of their selection of small particles as food source. Baleen whales feed by filtering small particles from large water volumes. Macroplastic was found in baleen whales before. This study is the first to show the presence of microplastic in intestines of a baleen whale (Megaptera novaeangliae). Contents of its gastrointestinal tract were sieved, dissolved in 10% potassium hydroxide and washed. From the remaining dried material, potential synthetic polymer particles were selected based on density and appearance, and analysed by Fourier transform infrared (FTIR) spectroscopy. Several polymer types (polyethylene, polypropylene, polyvinylchloride, polyethylene terephthalate, nylon) were found, in varying particle shapes: sheets, fragments and threads with a size of 1mm to 17cm. This diversity in polymer types and particle shapes, can be interpreted as a representation of the varying characteristics of marine plastic and the unselective way of ingestion by M. novaeangliae.
Mostrar más [+] Menos [-]Experimental and numerical investigations on reliability of air barrier on oil containment in flowing water
2015
Lu, Jinshu | Xu, Zhenfeng | Xu, Song | Xie, Sensen | Wu, Haoxiao | Yang, Zhenbo | Liu, Xueqiang
Air barriers have been recently developed and employed as a new type of oil containment boom. This paper presents systematic investigations on the reliability of air barriers on oil containments with the involvement of flowing water, which represents the commonly-seen shearing current in reality, by using both laboratory experiments and numerical simulations. Both the numerical and experimental investigations are carried out in a model scale. In the investigations, a submerged pipe with apertures is installed near the bottom of a tank to generate the air bubbles forming the air curtain; and, the shearing water flow is introduced by a narrow inlet near the mean free surface. The effects of the aperture configurations (including the size and the spacing of the aperture) and the location of the pipe on the effectiveness of the air barrier on preventing oil spreading are discussed in details with consideration of different air discharges and velocities of the flowing water. The research outcome provides a foundation for evaluating and/or improve the reliability of a air barrier on preventing spilled oil from further spreading.
Mostrar más [+] Menos [-]Estimating the willingness to pay to protect coral reefs from potential damage caused by climate change—The evidence from Taiwan
2015
Tseng, William Wei-Chun | Hsu, Shu-Han | Chen, Chi-Chung
Coral reefs constitute the most biologically productive and diverse ecosystem, and provide various goods and services including those related to fisheries, marine tourism, coastal protection, and medicine. However, they are sensitive to climate change and rising temperatures. Taiwan is located in the central part of the world's distribution of coral reefs and has about one third of the coral species in the world. This study estimates the welfare losses associated with the potential damage to coral reefs in Taiwan caused by climate change. The contingent valuation method adopted includes a pre-survey, a face-to-face formal survey, and photo illustrations used to obtain reliable data. Average annual personal willingness to pay is found to be around US$35.75 resulting in a total annual willingness to pay of around US$0.43 billion. These high values demonstrate that coral reefs in Taiwan deserve to be well preserved, which would require a dedicated agency and ocean reserves.
Mostrar más [+] Menos [-]Strategic planning to reduce conflicts for offshore wind development in Taiwan: A social marketing perspective
2015
Chen, Jyun-Long | Liu, Hsiang-Hsi | Chuang, Ching-Ta
This study aims to improve the current inefficiency and ineffectiveness of communications among stakeholders when planning and constructing offshore wind farms (OWFs). An analysis using a social marketing approach with segmentation techniques is used to identify the target market based on stakeholders’ perceptions. The empirical results identify three stakeholder segments: (1) impact-attend group; (2) comprehensive group; and (3) benefit-attend group. The results suggest that communication should be implemented to alter stakeholders’ attitudes toward the construction of OWFs. Furthermore, based on the results of segmentation, target markets are identified to plan the communication strategies for reducing the conflicts among stakeholders of OWF construction. The results also indicated that in the planning phase of construction for OWFs, effective stakeholder participation and policy communication can enhance the perception of benefits to reduce conflict with local communities and ocean users.
Mostrar más [+] Menos [-]Impact of CO2-driven acidification on the development of the sea cucumber Apostichopus japonicus (Selenka) (Echinodermata: Holothuroidea)
2015
Yuan, Xiutang | Shao, Senlin | duPont, Sam | Meng, Leiming | Liu, Yongjian | Wang, Lijun
We evaluated the impact of ocean acidification on the early development of sea cucumber Apostichopus japonicus. The effect of pH-levels (pH 8.04, 7.85, 7.70 and 7.42) were tested on post-fertilization success, developmental (stage duration) and growth rates. Post-fertilization success decreased linearly with pH leading to a 6% decrease at pH 7.42 as compared to pH 8.1. The impact of pH on developmental time was stage-dependent: (1) stage duration increased linearly with decreasing pH in early-auricularia stage; (2) decreased linearly with decreasing pH in the mid-auricularia stage; but (3) pH decline had no effect on the late-auricularia stage. At the end of the experiment, the size of doliolaria larvae linearly increased with decreasing pH. In conclusion, a 0.62 unit decrease in pH had relatively small effects on A. japonicus early life-history compared to other echinoderms, leading to a maximum of 6% decrease in post-fertilization success and subtle effects on growth and development.
Mostrar más [+] Menos [-]Electrospun PS/PAN fibers with improved mechanical property for removal of oil from water
2015
Li, Peng | Qiao, Ying | Zhao, Lili | Yao, Dahu | Sun, Haixiang | Hou, Yingfei | Li, Shuo | Li, Qi
A mechanically robust and high-capacity oil sorbent is prepared by electrospinning a blend of polystyrene (PS) and polyacrylonitrile (PAN). The morphology, oil sorption capacity and mechanical property of the fibers formed in different compositions are investigated in detail. It is shown that the oil sorption capacity is a result of both the chemical composition and the specific surface area which related to diameter size. The addition of PAN as a component in fibrous sorbents can significantly improve the mechanical properties of PS fibers. Moreover, the oil sorption capacity increases with decreasing fiber diameter. The results also show that the maximum sorption capacities of the PS/PAN sorbent for pump oil, peanut oil, diesel, and gasoline were 194.85, 131.70, 66.75, and 43.38gg−1, respectively. Additionally, the sorbent exhibits quick oil sorption speed as well as high buoyancy, which make it a promising candidate for use as an oil spill cleanup sorbent.
Mostrar más [+] Menos [-]Distribution and assessment of marine debris in the deep Tyrrhenian Sea (NW Mediterranean Sea, Italy)
2015
Angiolillo, Michela | Lorenzo, Bianca di | Farcomeni, Alessio | Bo, Marzia | Bavestrello, Giorgio | Santangelo, Giovanni | Cau, Angelo | Mastascusa, Vincenza | Cau, Alessandro | Sacco, Flavio | Canese, Simonepietro
Marine debris is a recognized global ecological concern. Little is known about the extent of the problem in the Mediterranean Sea regarding litter distribution and its influence on deep rocky habitats. A quantitative assessment of debris present in the deep seafloor (30–300m depth) was carried out in 26 areas off the coast of three Italian regions in the Tyrrhenian Sea, using a Remotely Operated Vehicle (ROV). The dominant type of debris (89%) was represented by fishing gears, mainly lines, while plastic objects were recorded only occasionally. Abundant quantities of gears were found on rocky banks in Sicily and Campania (0.09–0.12 debris m−2), proving intense fishing activity. Fifty-four percent of the recorded debris directly impacted benthic organisms, primarily gorgonians, followed by black corals and sponges. This work provides a first insight on the impact of marine debris in Mediterranean deep ecosystems and a valuable baseline for future comparisons.
Mostrar más [+] Menos [-]Evaluation of beach cleanup effects using linear system analysis
2015
Kataoka, Tomoya | Hinata, Hirofumi
We established a method for evaluating beach cleanup effects (BCEs) based on a linear system analysis, and investigated factors determining BCEs. Here we focus on two BCEs: decreasing the total mass of toxic metals that could leach into a beach from marine plastics and preventing the fragmentation of marine plastics on the beach. Both BCEs depend strongly on the average residence time of marine plastics on the beach (τr) and the period of temporal variability of the input flux of marine plastics (T). Cleanups on the beach where τr is longer than T are more effective than those where τr is shorter than T. In addition, both BCEs are the highest near the time when the remnants of plastics reach the local maximum (peak time). Therefore, it is crucial to understand the following three factors for effective cleanups: the average residence time, the plastic input period and the peak time.
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