خيارات البحث
النتائج 661 - 670 من 2,512
Real time observation system for monitoring environmental impact on marine ecosystems from oil drilling operations النص الكامل
2014
Godø, Olav Rune | Klungsøyr, Jarle | Meier, Sonnich | Tenningen, Eirik | Purser, Autun | Thomsen, Laurenz
Environmental awareness and technological advances has spurred development of new monitoring solutions for the petroleum industry.This paper presents experience from a monitoring program off Norway. To maintain operation within the limits of the government regulations Statoil tested a new monitoring concept. Multisensory data were cabled to surface buoys and transmitted to land via wireless communication. The system collected information about distribution of the drilling wastes and the welfare of the corals in relation to threshold values.The project experienced a series of failures, but the backup monitoring provided information to fulfil the requirements of the permit. The experience demonstrated the need for real time monitoring and how such systems enhance understanding of impacts on marine organisms. Also, drilling operations may improve by taking environmental information into account. The paper proposes to standardize and streamline monitoring protocols to maintain comparability during all phases of the operation and between drill sites.
اظهر المزيد [+] اقل [-]Severity of killer whale behavioral responses to ship noise: A dose–response study النص الكامل
2014
Critical habitats of at-risk populations of northeast Pacific “resident” killer whales can be heavily trafficked by large ships, with transits occurring on average once every hour in busy shipping lanes. We modeled behavioral responses of killer whales to ship transits during 35 “natural experiments” as a dose–response function of estimated received noise levels in both broadband and audiogram-weighted terms. Interpreting effects is contingent on a subjective and seemingly arbitrary decision about severity threshold indicating a response. Subtle responses were observed around broadband received levels of 130dB re 1μPa (rms); more severe responses are hypothesized to occur at received levels beyond 150dB re 1μPa, where our study lacked data. Avoidance responses are expected to carry minor energetic costs in terms of increased energy expenditure, but future research must assess the potential for reduced prey acquisition, and potential population consequences, under these noise levels.
اظهر المزيد [+] اقل [-]The distribution of dissolved lead in the coastal waters of the East China Sea النص الكامل
2014
The distribution of dissolved lead in the coastal waters of the East China Sea was investigated seasonally. The average concentrations in surface waters during the spring and autumn were 0.52nM and 0.27nM, respectively. In the spring, the concentration of dissolved Pb in the surface waters and bottom waters ranged from 0.13 to 1.86nM and from 0.15 to 0.94nM, respectively. For both the surface water and the bottom water, the highest values were observed at the Yangtze River Estuary. Seasonal variability of D-Pb between spring and autumn in the ECS was observed. These results suggested that riverine inputs and atmospheric inputs may be the main sources of lead in this area, while adsorption and co-precipitation on suspended particles at the river estuary and biological process may be the major sinks.
اظهر المزيد [+] اقل [-]Trace element contamination in the Guadalquivir River Estuary ten years after the Aznalcóllar mine spill النص الكامل
2014
Tornero, Victoria | Arias, Alberto M. | Blasco, Julián
Trace element contamination in the Guadalquivir River Estuary ten years after the Aznalcóllar mine spill النص الكامل
2014
Tornero, Victoria | Arias, Alberto M. | Blasco, Julián
Sediments, clams Scrobicularia plana and worms Hediste diversicolor from the Guadalquivir estuary were collected ten years after the Aznalcóllar mine spill and analyzed for metals. Significant seasonal and spatial effects were detected for most elements, so data from different sampling periods and locations were treated separately. Overall, the most polluted sites were found upstream, although Zn and Cu tended to accumulate at the estuary mouth. A significant decline of Zn in sediments and clams was observed compared to levels reported following the spill, so the estuarine ecosystem has recovered. However, the concentrations of some elements in S. plana were still higher than those of heavily contaminated regions. In this mollusk, Pb and As levels were higher in 2008 than in previous years, suggesting a new source entering into the estuary. Metals in sediments presented low bioavailability for biota, so other sources must account for the concentrations observed in these species.
اظهر المزيد [+] اقل [-]Trace element contamination in the Guadalquivir River Estuary ten years after the Aznalcóllar mine spill النص الكامل
2014
Tornero, Victoria | Arias, Alberto M. | Blasco, Julián | European Commission | Ministerio de Ciencia y Tecnología (España)
Sediments, clams Scrobicularia plana and worms Hediste diversicolor from the Guadalquivir estuary were collected ten years after the Aznalcóllar mine spill and analyzed for metals. Significant seasonal and spatial effects were detected for most elements, so data from different sampling periods and locations were treated separately. Overall, the most polluted sites were found upstream, although Zn and Cu tended to accumulate at the estuary mouth. A significant decline of Zn in sediments and clams was observed compared to levels reported following the spill, so the estuarine ecosystem has recovered. However, the concentrations of some elements in S. plana were still higher than those of heavily contaminated regions. In this mollusk, Pb and As levels were higher in 2008 than in previous years, suggesting a new source entering into the estuary. Metals in sediments presented low bioavailability for biota, so other sources must account for the concentrations observed in these species. | While doing this work, V. Tornero was fully supported by a I3P contract from the Programa Nacional de Potenciación de Recursos Humanos del Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (2000–2003). The presented study was supported as a part of the projects CTM2005-07282-C03-02/TECNO (Spanish Science and Technology National Plan) and Interreg IIIA REDCONTAMAR SP5 (SP3.E101/03). | Peer reviewed
اظهر المزيد [+] اقل [-]Out of sight but not out of mind: Harmful effects of derelict traps in selected U.S. coastal waters النص الكامل
2014
Arthur, Courtney | Sutton-Grier, Ariana E. | Murphy, Peter | Bamford, Holly
There is a paucity of data in the published literature on the ecological and economic impacts of derelict fishing traps (DFTs) in coastal ecosystems. We synthesized results from seven NOAA-funded trap fisheries studies around the United States and determined that DFT-caused losses to habitat and harvestable annual catch are pervasive, persistent, and largely preventable. Based on this synthesis, we identified key gaps to fill in order to better manage and prevent DFTs. We conclude with suggestions for developing a U.S. DFT management strategy including: (1) targeting studies to estimate mortality of fishery stocks, (2) assessing the economic impacts of DFTs on fisheries, (3) collaborating with the fishing industry to develop solutions to ghost fishing, and (4) examining the regional context and challenges resulting in DFTs to find effective policy solutions to manage, reduce, and prevent gear loss.
اظهر المزيد [+] اقل [-]Microbial release from seeded beach sediments during wave conditions النص الكامل
2014
Phillips, Matthew C. | Feng, Zhixuan | Vogel, Laura J. | Reniers, Ad J.H.M. | Haus, Brian K. | Enns, Amber A. | Zhang, Yifan | Hernandez, David B. | Solo-Gabriele, Helena M.
Beach sands can sustain indigenous and introduced populations of enterococci. The objective of this study was to evaluate wave action in promoting the release of introduced bacteria. To accomplish this objective this study developed a method to assess attachment and identified conditions under which introduced bacteria are integrated into the sand. A new “shearing assay” showed that attachment of the introduced spike mimicked that of the natural sand when the spike was allowed to integrate into the sand for 24h at room temperature at a sand moisture content of 20%. Experiments in a wave flume showed that waves were capable of releasing about 60% of the total bacteria added. This suggests that for the range of wave conditions evaluated (height: 1.9–10.5cm, period:1–2.7s), waves were incapable of releasing all of the bacteria. Further study is needed to evaluate bacteria attachment mechanisms.
اظهر المزيد [+] اقل [-]The interaction between organic phosphate ester and p53: An integrated experimental and in silico approach النص الكامل
2014
Li, Fei | Li, Renmin | Yang, Xianhai | You, Liping | Zhao, Jianmin | Wu, Huifeng
Concerns have been raised in regards to the environmental impact of the more used organophosphate flame retardants (OPFRs). In this study, to better understand the relationship between molecular structural features of OPFRs and binding affinity for the tumor suppressor p53, an integrated experimental and in silico approach was used. From docking analysis, hydrogen bonding and hydrophobic interactions were found to be the dominant interactions, which implied the binding affinities of the compounds. The binding constants of 5 OPFRs were determined by surface plasmon resonance technology (SPR). Based on the observed interactions, appropriate molecular structural parameters were adopted to develop a quantitative structure-activity relationship (QSAR) model. The developed QSAR model had good robustness, predictive ability and mechanism interpretability. The interactions between the OPFRs and p53 (Ebinding) and the partition ability of the OPFRs into the bio-phase are main factors governing the binding affinities.
اظهر المزيد [+] اقل [-]Polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in the equatorial Indian Ocean: Temporal trend, continental outflow and air–water exchange النص الكامل
2014
Nineteen pairs of air and seawater samples collected from the equatorial Indian Ocean onboard the Shiyan I from 4/2011 to 5/2011 were analyzed for PCBs and HCB. Gaseous concentrations of ∑ICESPCBs (ICES: International Council for the Exploration of the Seas) and HCB were lower than previous data over the study area. Air samples collected near the coast had higher levels of PCBs relative to those collected in the open ocean, which may be influenced by proximity to source regions and air mass origins. Dissolved concentrations of ∑ICESPCBs and HCB were 1.4–14pgL−1 and 0.94–13pgL−1, with the highest concentrations in the sample collected from Strait of Malacca. Fugacity fractions suggest volatilization of PCBs and HCB from the seawater to air during the cruise, with fluxes of 0.45–34ngm−2d−1 and 0.36–18ngm−2d−1, respectively.
اظهر المزيد [+] اقل [-]The larvae of congeneric gastropods showed differential responses to the combined effects of ocean acidification, temperature and salinity النص الكامل
2014
The larvae of congeneric gastropods showed differential responses to the combined effects of ocean acidification, temperature and salinity النص الكامل
2014
The tolerance and physiological responses of the larvae of two congeneric gastropods, the intertidal Nassarius festivus and subtidal Nassarius conoidalis, to the combined effects of ocean acidification (pCO2 at 380, 950, 1250ppm), temperature (15, 30°C) and salinity (10, 30psu) were compared. Results of three-way ANOVA on cumulative mortality after 72-h exposure showed significant interactive effects in which mortality increased with pCO2 and temperature, but reduced at higher salinity for both species, with higher mortality being obtained for N. conoidalis. Similarly, respiration rate of the larvae increased with temperature and pCO2 level for both species, with a larger percentage increase for N. conoidalis. Larval swimming speed increased with temperature and salinity for both species whereas higher pCO2 reduced swimming speed in N. conoidalis but not N. festivus. The present findings indicated that subtidal congeneric species are more sensitive than their intertidal counterparts to the combined effects of these stressors.
اظهر المزيد [+] اقل [-]The larvae of congeneric gastropods showed differential responses to the combined effects of ocean acidification, temperature and salinity النص الكامل
2014
Zhang, Haoyu | Cheung, S G | Shin, Paul K S
The tolerance and physiological responses of the larvae of two congeneric gastropods, the intertidal Nassarius festivus and subtidal Nassarius conoidalis, to the combined effects of ocean acidification (PCO2 at 380, 950, 1250 ppm), temperature (15, 30 degrees C) and salinity (10, 30 psu) were compared. Results of three-way ANOVA on cumulative mortality after 72-h exposure showed significant interactive effects in which mortality increased with pCO(2) and temperature, but reduced at higher salinity for both species, with higher mortality being obtained for N. conoidalis. Similarly, respiration rate of the larvae increased with temperature and pCO(2) level for both species, with a larger percentage increase for N. conoidalis. Larval swimming speed increased with temperature and salinity for both species whereas higher pCO(2) reduced swimming speed in N. conoidalis but not N. festivus. The present findings indicated that subtidal congeneric species are more sensitive than their intertidal counterparts to the combined effects of these stressors. (c) 2014 Elsevier Ltd. All rights reserved.
اظهر المزيد [+] اقل [-]Carbonyl concentrations from sites affected by emission from different fuels and vehicles النص الكامل
2014
Concentrations of carbonyl compounds were evaluated on places impacted by emissions from different fuels and vehicles. In order to evaluate the concentrations, four campaigns during the winter and summer of 2011 and 2012 were performed, inside a covered parking area in a commercial establishment where mainly gasohol and ethanol vehicles are in circulation. Also, measurements were done inside a semi–closed bus station, which is the direct source of emissions from heavy duty vehicles (i.e. buses) burning B3–diesel (3% biodiesel and 97% diesel). The results indicated that acetaldehyde is the main aldehyde emitted by light vehicles due to large use of ethanol in Brazil by these vehicles. In addition, the concentrations found in the bus station revealed that B3–diesel fuel increases the emissions of carbonyl compounds and that of acetaldehyde when compared with results from B0–diesel at same bus station. Possible impacts of changing diesel to B3–diesel indicate an increase of ozone formation. In terms of health, a lower impact was estimated considering only the changes in formaldehyde concentrations.
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