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Coral morphology and sedimentation Полный текст
2017
Duckworth, Alan | Giofre, Natalie | Jones, Ross
The sediment rejection ability of 8 coral species of 5 families and 3 morphologies were assessed in a series of short term exposure tests over a sedimentation range of 0.5–40mgcm−2d−1 and one longer term exposure test of 235mgcm−2. Sediment accumulation rates on live corals and dead (enamel-covered) skeletons varied between morphologies, with branching species often more adept at self-cleaning. Flow rates (0–17cms−1) significantly affected sediment-shedding ability as did differences in particle sizes, with coarse silt rejected faster than fine silt, but only at very high (235mgcm−2) deposition rates. Siliciclastic sediment was rejected faster than carbonate sediments and smothering for many days by mms of low organic content carbonate sediment resulted in bleaching, but no mortality. The findings are discussed with respect to turbidity generated in natural and dredging-related resuspension events and in the context for impact prediction for dredging projects.
Показать больше [+] Меньше [-]What are the roadblocks to using population models in ecotoxicology studies? Полный текст
2017
O'Brien, Allyson L.
Understanding how pollution affects populations is critical for targeted environmental risk assessments and adequate protection of the environment. However, the vast majority of ecotoxicology studies still have a traditional focus of identifying effects on individual organisms and do not measure the effects at the population-level. Modelling tools that measure population effects of pollution are available and would add value to current ecotoxicology studies by aligning outcomes more closely to what needs to be protected. In this paper I outline three possible reasons why this knowledge gap still exists and consider how they could be adopted more broadly, including better considerations about what endpoints should be measured at the initial study design phase. The purpose of highlighting this knowledge gap is to assist in facilitating the integration of population-level endpoints into routine pollution monitoring programs and progress of ecologically relevant ecotoxicology research.
Показать больше [+] Меньше [-]Using a multi-biomarker approach to assess the effects of pollution on sand flathead (Platycephalus bassensis) from Port Phillip Bay, Victoria, Australia Полный текст
2017
Fu, Dingkun | Bridle, Andrew | Leef, Melanie | Gagnon, Marthe Monique | Hassell, Kathryn L. | Nowak, Barbara F.
Hepatic gene expression and liver histology were examined in sand flathead (Platycephalus bassensis) from six locations in Port Phillip Bay, Victoria, Australia. Four sets of genes including thyroid-related genes (D1, D2, TTR, TRα and TRβ), metal metabolism-related genes (MT, MTF1, TF, Ferritin and FPN1), apoptosis-related genes (Diablo/SMAC1, Diablo/SMAC2 and CYP1A) and an endoplasmic reticulum stress biomarker gene (GRP78) were examined in female flathead using qRT-PCR. TRβ and Diablo/SMAC1 gene expression was significantly up-regulated in fish from all polluted sites compared to those from a reference site. The transcripts of TRα and FPN1 were significantly higher in flathead from Corio Bay, while the hepatic mRNA of TTR and GRP78 were significantly lower in those fish. Positive correlations were observed between Diablo/SMAC1 and CYP1A, D2 and TRβ, TRα and TRβ. This study demonstrates that application of pathway-based biomarker genes and histopathology can provide comprehensive information on the impact of environmental pollutants on fish.
Показать больше [+] Меньше [-]Characteristics and origins of air pollutants and carbonaceous aerosols during wintertime haze episodes at a rural site in the Yangtze River Delta, China Полный текст
2017
Bao, Mengying | Cao, Fang | Chang, Yunhua | Zhang, Yan-Lin | Gao, Yaqi | Liu, Xiaoyan | Zhang, Yuanyuan | Zhang, Wenqi | Tang, Tianran | Xu, Zufei | Liu, Shoudong | Lee, Xuhui | Li, Jun | Zhang, Gan
China has frequently suffered regional-scale haze pollution in recent years. In this study, real-time observation data such as PM2.5, PM10, SO2, NO2, CO and O3 were used to analyze wintertime haze events at a rural site (Dongshan) in the Yangtze River Delta (YRD). 3-hour resolution organic carbon (OC) and elemental carbon (EC) were also measured to further investigate the sources of PM2.5. The hybrid receptor models were used to identify source regions of PM2.5. The results showed that both regional transport and local emissions significantly contribute to air pollution at Dongshan during haze periods. The source areas affecting high PM2.5 concentrations were mainly located in nearby urbanized provinces (i.e., Jiangsu, Anhui and Zhejiang) and industrial provinces (i.e., Shandong and Hebei) in eastern China. Furthermore, open biomass-burning emissions in south China (i.e., Jiangxi, Hunan, Guangdong and Fujian) decreased regional air quality, which was supported by MODIS fire spots and receptor models. During clean periods, air masses were originated from remote regions such as Mongolia and oceanic areas (i.e., the Yellow Sea and the East Sea). Enhanced secondary organic carbon (SOC) formation was found under long-range transport when OC aging was favorable. Contrarily, relatively low SOC formation was found when the site was dominated by local emissions. In addition to local emissions, high PM2.5 concentrations at Dongshan were apparently affected by either regional or long-range transport, which were characterized by relatively low and high wind speeds, respectively. It is necessary to implement the emission control strategies for the industrial and urbanized areas.
Показать больше [+] Меньше [-]Droplet and bubble formation of combined oil and gas releases in subsea blowouts Полный текст
2017
Zhao, Lin | Boufadel, Michel C. | King, Thomas | Robinson, Brian | Gao, Feng | Socolofsky, Scott A. | Lee, Kenneth
Underwater blowouts from gas and oil operations often involve the simultaneous release of oil and gas. Presence of gas bubbles in jets/plumes could greatly influence oil droplet formation. With the aim of understanding and quantifying the droplet formation from Deepwater Horizon blowout (DWH) we developed a new formulation for gas-oil interaction with jets/plumes. We used the jet-droplet formation model VDROP-J with the new module and the updated model was validated against laboratory and field experimental data. Application to DWH revealed that, in the absence of dispersant, gas input resulted in a reduction of d50 by up to 1.5mm, and maximum impact occurred at intermediate gas fractions (30–50%). In the presence of dispersant, reduction in d50 due to bubbles was small because of the promoted small sizes of both bubbles and droplets by surfactants. The new development could largely enhance the prediction and response to oil and gas blowouts.
Показать больше [+] Меньше [-]A model for the weathering of Colombian crude oils in the Colombian Caribbean Sea Полный текст
2017
Ramírez, Juan | Merlano, Aura | Lacayo, Juan | Osorio, Andres F. | Molina, Alejandro
A model that describes the weathering of crude in an oil spill caused by interaction with the atmosphere and the ocean was developed. This model was adapted to the Colombian crudes Cusiana (°API43.2) and Vasconia (°API20.7). To calibrate the model, evaporation and emulsification experiments were carried out at conditions similar to those of an oil spill in the Colombian Caribbean Sea. The dependence of evaporation with wind velocity, not predicted by the state-of-the-art models, was captured by a correlation for the mass transfer coefficient calculated from the experimental data. Emulsification rate, maximum water content and required evaporation to form an emulsion were determined and their values explained considering the effect of wax precipitation for Cusiana crude oil. When compared to well-established weathering software, such as ADIOS, the proposed model predicts the weathering of Colombian oils in a way that better agrees with the experiments conducted in the laboratory.
Показать больше [+] Меньше [-]Exceptionally high abundances of microplastics in the oligotrophic Israeli Mediterranean coastal waters Полный текст
2017
van der Hal, Noam | Ariel, Asaf | Angel, Dror L.
Seasonal sea surface microplastic distribution was recorded at 17 sites along the Israeli Mediterranean coast. Microplastics (0.3–5mm) were found in all samples, with a mean abundance of 7.68±2.38particles/m3 or 1,518,340particles/km2. Some areas had higher abundances of microplastics than others, although differences were neither consistent nor statistically significant. In some cases microplastic particles were found floating in large patches. One of these patches contained an extraordinary number of plastic particles; 324particles/m3 or 64,812,600particles/km2. Microplastic abundances in Israeli coastal waters are disturbingly high; mean values were 1–2 orders of magnitude higher than abundances reported in other parts of the world. Light-colored (white or transparent) fragments were by far more abundant than all other microplastic colors and types. The results of this study underline the need for action to reduce the flux of plastics to the marine environment.
Показать больше [+] Меньше [-]Assessing human exposure to PM10-bound polycyclic aromatic hydrocarbons during fireworks displays Полный текст
2017
Pongpiachan, Siwatt | Hattayanone, Mattanawadee | Suttinun, Oramas | Khumsup, Chukkapong | Kittikoon, Itthipon | Hirunyatrakul, Phoosak | Cao, Junji
The “Loy Krathong” festival is a major annual Thai event that includes firework displays. It takes place on the evening of the full moon in the 12th month of the traditional Thai lunar calendar. Since fireworks are widely considered a major source of PAHs, it is considered reasonable to expect a significant increase in PAH levels during this event. The overall PAH profile at the six air quality observatories operated by the Pollution Control Department (PCD), Ministry of Natural Resources and Environment (MNRE), showed that the Kingdom of Thailand's atmosphere was dominated by 5–6-ring PAHs during the firework display period. A significant increase in ΣPAHs (153%) was observed during firework displays. A statistical analysis coupled with the application of diagnostic binary PAH ratios was conducted to determine whether the detected increase in PAH congeners during the festival period was due to firework combustion or whether it was a coincidental effect caused by vehicular exhausts, long-range atmospheric transportation, photolysis and chemical degradation. The average incremental lifetime cancer risk (ILCR) values of adults and children living in Bangkok as estimated by three different TEQs for ingestion, dermal contact, and inhalation exposure pathways were greatly lesser than the US EPA baseline, further highlighting that the cancer risk of bonfire night falls into the ‘‘acceptable level’’ range.
Показать больше [+] Меньше [-]The value of remote sensing techniques in supporting effective extrapolation across multiple marine spatial scales Полный текст
2017
Strong, J. (James Asa) | Elliott, Michael
The reporting of ecological phenomena and environmental status routinely required point observations, collected with traditional sampling approaches to be extrapolated to larger reporting scales. This process encompasses difficulties that can quickly entrain significant errors. Remote sensing techniques offer insights and exceptional spatial coverage for observing the marine environment. This review provides guidance on (i) the structures and discontinuities inherent within the extrapolative process, (ii) how to extrapolate effectively across multiple spatial scales, and (iii) remote sensing techniques and data sets that can facilitate this process. This evaluation illustrates that remote sensing techniques are a critical component in extrapolation and likely to underpin the production of high-quality assessments of ecological phenomena and the regional reporting of environmental status. Ultimately, is it hoped that this guidance will aid the production of robust and consistent extrapolations that also make full use of the techniques and data sets that expedite this process.
Показать больше [+] Меньше [-]Plastic debris and microplastics along the beaches of the Strait of Hormuz, Persian Gulf Полный текст
2017
Naji, Abolfazl | Esmaili, Zinat | Khan, Farhan R
Currently little is known about the prevalence of plastics and microplastics (MPs) in the Persian Gulf. Five sampling stations were selected along the Strait of Hormuz (Iran) that exhibited different levels of industrialization and urbanization, and included a marine protected area. Debris was observed and sediments were collected for MPs extraction via fluidization/floatation methodology. The order of MP abundance (par/kg) generally reflected the level of anthropogenic activity: Bostanu (1258±291)>Gorsozan (122±23)>Khor-e-Yekshabeh (26±6)>Suru (14±4)>Khor-e-Azini (2±1). Across all sites fibers dominated (83%, 11% film, 6% fragments). FT-IR analysis showed polyethylene (PE), nylon, and PET (polyethylene terephthalate) were the commonly recovered polymers. Likely sources include beach debris, discarded fishing gear, and urban and industrial outflows that contain fibers from clothes. This study provides a ‘snapshot’ of MP pollution and longitudinal studies are required to fully understand plastic contamination in the region.
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