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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Predicting retention of diluted bitumen in marine shoreline sediments, Southeastern Vancouver Island, British Columbia, Canada

Britton, Lee Allen Sean 22 December 2017 (has links)
Canada has become increasingly economically dependent on the exportation of bitumen to trans-oceanic international markets. As the export of Alberta bitumen from ports located in British Columbia increases, oil spill response and readiness measures become increasingly important. Although the frequency of ship-source oil spills has dramatically declined over the past several decades, they remain environmentally devastating when they occur. In the event of a marine spill, great lengths of shoreline are at risk of being contaminated. Once ashore, oil can persist for decades if shoreline hydraulic conditions are correct and remediation does not occur. Most commonly transported oils (e.g., fuel oils, Bunker C, crude oil, etc.) have been thoroughly studied, and their fate and behaviour in the event of a marine spill is well understood. In contrast, because diluted bitumen has been historically traded in relatively low quantities and has almost no spill history, there is a sizable knowledge gap regarding its effects and behaviour in both the marine environment and on coastal shorelines. The intent of this thesis was to develop a classification scheme to identify marine shorelines of high and low diluted bitumen (dilbit) retention for southeastern Vancouver Island, British Columbia. This study builds upon the outcome of former laboratory bench top dilbit and sediment research known as Bitumen Experiments (Bit_Ex). Bit_Ex investigated dilbit penetration and retention in six engineered sediment classifications ranging from coarse sand to very large pebble in accordance with the Wentworth Classification scheme. This research used Bit_Ex findings to predict dilbit retention in poorly sorted in-situ beach sediments found on shorelines representative of the southern coast of Vancouver Island, British Columbia, Canada. Field and laboratory measurements were conducted to document the occurrence of in-situ shoreline sediments and hydraulic conditions and were used to predict dilbit retention by comparing such characteristics between Bit_Ex and unconsolidated in-situ beach sediments. Saturated hydraulic conductivity (Ks) was measured using a double-ring constant-head infiltrometer. Measured Ks values were then compared to predicted Ks values generated by five semi-empirical Ks equations. A modified version of the Hazen Approximation was selected as the most appropriate. Using measured and calculated metrics, sediments were grouped as having either low or high dilbit retention. When sediments were analysed as homogenous samples, the experimental results suggested two of ten shorelines were composed of a combination of low and high retention sections, while the remaining eight sites were of low retention. Upon the isolation of coarse surface strata, results indicated two shorelines were entirely veneered with high retention sediments, and four shorelines were a combination of high and low retention. The residual four shorelines were found to be entirely composed of low retention sediments. The results illuminate the importance of shoreline stratification when predicting shoreline oil retention. This characteristic is a factor that current shoreline oil retention mapping techniques do not adequately consider. Additionally, the findings suggest that while sediments indicative of retaining weathered dilbit are relatively uncommon within Juan de Fuca and Harro Straits, high retention unweathered dilbit sediments are more common. / Graduate / 2018-06-26
32

Influence of Petroleum Deposit Geometry on Local Gradient of Electron Acceptors and Microbial Catabolic Potential

Singh, Gargi 17 April 2012 (has links)
A field survey was conducted following the Deepwater Horizon blowout and it was noted that resulting coastal petroleum deposits possessed distinct geometries, ranging from small tar balls to expansive horizontal oil sheets. A laboratory study evaluated the effect of oil deposit geometry on localized gradients of electron acceptors and microbial community composition, factors that are critical to accurately estimating biodegradation rates. One-dimensional top-flow sand columns with 12-hour simulated tidal cycles compared two contrasting geometries (isolated tar "balls" versus horizontal "sheets") relative to an oil-free control. Significant differences in the effluent dissolved oxygen and sulfate concentrations were noted among the columns, indicating presence of anaerobic zones in the oiled columns, particularly in the sheet condition. Furthermore, quantification of genetic markers of electron acceptor and catabolic conditions via quantitative polymerase chain reaction of dsrA (sulfate-reduction), mcrA (methanogenesis), and cat23 (oxygenation of aromatics) genes in column cores suggested more extensive anaerobic conditions induced by the sheet relative to the ball geometry. Denaturing gradient gel electrophoresis similarly revealed that distinct gradients of bacterial communities established in response to the different geometries. Thus, petroleum deposit geometry impacts local redox and microbial characteristics and may be a key factor for advancing attenuation models and prioritizing cleanup. / Master of Science
33

De novo Transcriptome Analysis of the Marine Sponge Cinachyrella spp: A Potential Model Organism for Oil and Dispersant Ecotoxicology

Smith, Emily 01 May 2013 (has links)
In order to study the potential effects of an oil spill on coral reef organisms, the marine sponge, Cinachyrella spp. was investigated. In this study, Cinachyrella spp. was placed in a closed aquaculture system and exposed to sub-lethal water-accommodated fractions (WAFs) of Macondo crude oil and chemically-enhanced water accommodated fractions (CE-WAFs) of the dispersant, Corexit 9500, over a 24-hour time course, in order to model the BP Deepwater Horizon oil spill and oil spill sponge response. Illumina RNA sequencing and gene expression analysis utilizing hierarchical clustering, principal component analysis, and KEGG bioinformatic database generated 34,147 unique transcripts with differential expression of 483 transcripts across all samples related to metabolism, genetic, environmental, and cellular processes, and associations with pathways involved in human disease development and progression. These pathways highlight the induction of Rac1, a GTPase in the Ras superfamily responsible for cell proliferation, differentiation, and senescence and SOS, a set of specialized Ras-GTP activators. These Ras-regulated signaling proteins are thought to play a significant role in the development of human malignancies, specifically Rac1. The data reported here helps support the possible role of Cinachyrella spp. as an ecotoxicological model for oil and dispersant pollution as well as the identification of potential biomarkers of stress and environmental perturbation. These results have important implications in identifying stress response in coral reef associated communities, and will ultimately be useful in coral reef conservation, management, and oil spill mitigation activities.
34

Biodegradation of Petroleum Hydrocarbons in Contaminated Coastal Environments, Nigeria

ONIBIYO, SAMSON 14 December 2016 (has links)
ABSTRACT To compare the degree of biodegradation of petroleum hydrocarbons in sediments from Ikarama and Okwori in the Niger delta, Nigeria, concentrations of n-alkanes and polycyclic aromatic hydrocarbons in the sediments were measured. Analysis was conducted with gas chromatography using mass spectrometry detector. While the decrease in concentrations of n-alkanes and polycyclic aromatic hydrocarbons confirmed the process of biodegradation in the sediments it was not solely fit to substantiate the degree of biodegradation in the sediments. Hence the percentage proportion of n-alkanes and polycyclic aromatic hydrocarbons was used. The degree of biodegradation of n-alkanes in both Okwori and Ikarama was almost similar. However, it was observed that polycyclic aromatic hydrocarbons were biodegraded in Okwori sediments than Ikarama sediments and this indicates the degree of biodegradation of petroleum hydrocarbons impacted sediments in Okwori is greater than that of Ikarama.
35

Modelagem numérica do comportamento de derrames de óleo como método de gestão ambiental, em planos de contingência, aplicada ao canal de São Sebastião (SP). / Numerical model of oil spill as an environmental management method in contingency plan, applied to São Sebastião channel (SP).

Rodrigues, Marcelo 10 September 2009 (has links)
A aplicação de modelagem numérica para análise acidentes envolvendo derrames de óleo se tornou uma das principais ferramentas para o estudo deste tipo de impacto ambiental, auxiliando na previsão do deslocamento e permitindo maior eficácia nas formas de atuação nos processos de contingência do deslocamento da mancha. Estes pressupostos dão impulso ao desenvolvimento de pesquisa aplicada neste caso específico de estudo, ou seja, de modelação hidrodinâmica no Canal de São Sebastião em vários cenários através da utilização do módulo hidrodinâmico do software MIKE 21 da DHI, e da avaliação dos resultados gerados pela simulação através de comparação com o acompanhamento de eventos reais de espalhamento de manchas de óleo em acidentes antigos e com uma imagem de satélite simultânea a um derramamento. Foram avaliados sete eventos distintos onde ocorreram vazamentos de óleo no Canal de São Sebastião e a eles comparados às simulações hidrodinâmicas geradas pelo modelo em diferentes condições ambientais. Os resultados obtidos mostram que o deslocamento da mancha de óleo está condicionado preferencialmente pelo regime de ventos, estando bem correlacionados com os padrões hidrodinâmicos encontrados. A partir das diferentes situações apresentadas nas simulações, é possível estimar o sentido do deslocamento em acidentes futuros, dando subsídios nas ações de contenção dos efeitos deste tipo de acidente. / The application of numeric models for analysis of oil spill in the coastal environments becomes one of the most important ways to understand the behavior of the oil in this case of impact, giving subsides to the prediction of the displacement of the patches and allowing best efficiency in the control of the extension of the impact agent. These assumptions give thrust to the development of applied research in this work, which is defined by the knowledge of the different hydrodynamic conditions that compose the oceanographic structure in the São Sebastião Channel, by the utilization of the software MIKE 21 of the DHI (Danish Hydrodynamic Institute) and the comparison with historic cases of spill described in the literature. A satellite image was processed showing the real conditions of the spill, considering the physic-chemical changes and compared with the other data improve the evaluation process. Seven oil spills were studied and compared to the simulations, and there were generated six scenarios in different environmental conditions. The results show that the most important forcing of the environmental conditions of the oil patch is the wind, and the simulations agree well with the real processes. The hydrodynamic module of Mike 21 reveals an applicable tool for this kind of studies, giving sufficient information to reduce the impact of oil spill improving the oil spill contention.
36

An Analysis of Oil Combustion on Snow

Alshuqaiq, Mohammad Abdullah 08 May 2014 (has links)
Several Arctic council reports conclude that oil spills are the most significant threat to the Arctic ecosystem. Some studies have shown that in-situ burning (ISB) of oil spills over water can remove more than 90% of the oil, and is the most promising technology for an efficient response to oil spills in the Arctic region. The definition of "In situ" is intentional, controlled burning of oil in place (i.e., without extracting or removing the oil first). Earlier studies [Bellino (WPI 2012), Farahani, (WPI 2014)] have investigated burning behavior of crude oil on ice, similar to what one would expect in sea-ice or bare lake ice conditions. The focus of the current study is to investigate the burning behavior of crude oil in snow, similar to oil spills in snow-covered land, or in snow covered sea ice in the Arctic. Understandably, due to the difference in packing density between ice/water and snow, the parameters that influence burning behavior of oil in snow are different compared to burning oil in the sea or ice conditions. The current experimental study shows that the snow behaves as a porous medium, and depending on the porosity and volume of the oil spill, two extreme behaviors are exhibited. In the case of an oil spill on snow with low porosity, the oil sinks easily to the bottom, and the burning involves, significant thermo capillary effects enabling the oil to rise up and burn. On the other hand, if the snow is less porous, most of the oil layer remains on the surface, approaching the case of an ice bed. However, the melting of snow due to flame heat flux causes a circulating flow pattern of the oil, whereby the hot layer at the surface moves down and comes back up due to capillary action. These processes, which have not been observed in the earlier studies, are physically explained in this study. The implications to overall efficiency of the burning process, which represents the amount of crude oil left in the snow after the burning process is discussed. The results will ultimately improve the strategies and the net environmental benefit of, and by it the success of, oil clean-up after an accidental spill on snow.
37

Hydrodynamics of contained oil slicks

Van Houten, Robert James January 1976 (has links)
Thesis. 1976. Ph.D.--Massachusetts Institute of Technology. Dept. of Ocean Engineering. / Microfiche copy available in Archives and Engineering. / Bibliography: leaves 83-84. / by Robert J. Van Houten. / Ph.D.
38

Modelagem numérica do comportamento de derrames de óleo como método de gestão ambiental, em planos de contingência, aplicada ao canal de São Sebastião (SP). / Numerical model of oil spill as an environmental management method in contingency plan, applied to São Sebastião channel (SP).

Marcelo Rodrigues 10 September 2009 (has links)
A aplicação de modelagem numérica para análise acidentes envolvendo derrames de óleo se tornou uma das principais ferramentas para o estudo deste tipo de impacto ambiental, auxiliando na previsão do deslocamento e permitindo maior eficácia nas formas de atuação nos processos de contingência do deslocamento da mancha. Estes pressupostos dão impulso ao desenvolvimento de pesquisa aplicada neste caso específico de estudo, ou seja, de modelação hidrodinâmica no Canal de São Sebastião em vários cenários através da utilização do módulo hidrodinâmico do software MIKE 21 da DHI, e da avaliação dos resultados gerados pela simulação através de comparação com o acompanhamento de eventos reais de espalhamento de manchas de óleo em acidentes antigos e com uma imagem de satélite simultânea a um derramamento. Foram avaliados sete eventos distintos onde ocorreram vazamentos de óleo no Canal de São Sebastião e a eles comparados às simulações hidrodinâmicas geradas pelo modelo em diferentes condições ambientais. Os resultados obtidos mostram que o deslocamento da mancha de óleo está condicionado preferencialmente pelo regime de ventos, estando bem correlacionados com os padrões hidrodinâmicos encontrados. A partir das diferentes situações apresentadas nas simulações, é possível estimar o sentido do deslocamento em acidentes futuros, dando subsídios nas ações de contenção dos efeitos deste tipo de acidente. / The application of numeric models for analysis of oil spill in the coastal environments becomes one of the most important ways to understand the behavior of the oil in this case of impact, giving subsides to the prediction of the displacement of the patches and allowing best efficiency in the control of the extension of the impact agent. These assumptions give thrust to the development of applied research in this work, which is defined by the knowledge of the different hydrodynamic conditions that compose the oceanographic structure in the São Sebastião Channel, by the utilization of the software MIKE 21 of the DHI (Danish Hydrodynamic Institute) and the comparison with historic cases of spill described in the literature. A satellite image was processed showing the real conditions of the spill, considering the physic-chemical changes and compared with the other data improve the evaluation process. Seven oil spills were studied and compared to the simulations, and there were generated six scenarios in different environmental conditions. The results show that the most important forcing of the environmental conditions of the oil patch is the wind, and the simulations agree well with the real processes. The hydrodynamic module of Mike 21 reveals an applicable tool for this kind of studies, giving sufficient information to reduce the impact of oil spill improving the oil spill contention.
39

Polycyclic Aromatic Hydrocarbon Metabolites as a Biomarker of Exposure to Oil in Demersal Fishes Following the <em>Deepwater Horizon</em> Blowout

Snyder, Susan Susan 05 November 2014 (has links)
The Deepwater Horizon blowout occurred on April 20th, 2010, releasing 4.9 million barrels of Louisiana crude oil into the Gulf of Mexico (GoM). Subsequent to the Deepwater Horizon blowout, sediment cores revealed oil on the northern GoM seafloor and abnormal skin lesions were seen in GoM fishes. Exposure to polycyclic aromatic hydrocarbons (PAHs), a component of crude oil, in fish has been associated with many sublethal effects, including cancer and population-level effects. Using a biomarker of exposure to PAHs, this thesis evaluates inter-species, temporal and spatial differences in exposure to hydrocarbon contamination between three species of fish with varying levels of association with the sediment, that were potentially exposed to Deepwater Horizon crude oil: golden tilefish (Lopholatilus chamaeleonticeps), king snake eel (Ophichthus rex) and red snapper (Lutjanus campechanus), and examines patterns in these data using life history, behavior and environmental data. In 2011, 2012 and 2013, bile samples and biometric data were collected from fish via demersal longlining and bile was analyzed for three PAHs, naphthalene, phenanthrene and benzo[a]pyrene and their metabolites, using high performance liquid chromatography with fluorescence detection (HPLC-F). Bile of golden tilefish had significantly higher concentrations of naphthalene and phenanthrene metabolites, compared to red snapper and king snake eel. For biliary naphthalene metabolites, golden tilefish had an average concentration of 240 ug g-1, compared to 61 ug g-1 for red snapper and 38 ug g-1 for king snake eel, for the year 2012. Biliary naphthalene metabolite concentration has decreased 8% in golden tilefish samples, between 2012 and 2013, indicating continuous exposure to petrogenic pollution, while naphthalene metabolites decreased 49% over time for red snapper and 37% for king snake eel, indicating episodic exposure to elevated petrogenic pollution prior to 2011. The concentration of naphthalene metabolites measured in golden tilefish in this study are some of the highest concentrations measured in the GoM and internationally, while naphthalene metabolite concentrations for red snapper and king snake eel are similar to 1990's GoM data. In contrast, concentrations of benzo[a]pyrene metabolites were statistically similar for all three species, suggesting a difference in the disposition of or exposure to benzo[a]pyrene contamination. Concentrations of benzo[a]pyrene metabolites are relatively low when compared to other GoM and international data, for all three species. This study has identified a species of GoM fish, golden tilefish, that is exposed to a present-day source of petrogenic PAH pollution and certain fish species that were episodically exposed, in the years following the Deepwater Horizon blowout. With residual Deepwater Horizon oil still found in GoM sediments, coastal marshes and beaches, there is a need to identify these chronic exposures to persistent PAH pollution, monitor PAH concentrations in over time and evaluate the resulting sublethal effects to better understand the impacts of the Deepwater Horizon blowout on marine resources such as GoM fisheries.
40

Cloning and Characterization of IL-1β, IL-8, IL-10, and TNFα from Golden Tilefish (<em>Lopholatilus chamaeleonticeps</em>) and Red Snapper (<em>Lutjanus campechanus</em>)

Deak, Kristina L. 04 November 2014 (has links)
Cytokines are pleiotropic and redundant signaling molecules that govern the inflammatory response and immunity, a critical ecological parameter for organism success and population growth. Produced at the site of injury or pathogen intrusion by a variety of cell types, cytokines mediate cell-signaling in either an autocrine or paracrine manner. The type and magnitude of the cytokine milieu produced subsequently dictates the strength and form of immune response. As the most diverse vertebrate group, with a high sensitivity to contaminants, fish represent an important foci for the evaluation of immune system evolution, function, and alteration upon toxicant exposure. While many cytokines have been identified in teleosts, primary study has been limited to model species (e.g. zebrafish and fugu). However, evidence exists for several variations of cytokine genes within taxa, underscoring the need for species-specific evaluation. In this study, two pro-inflammatory cytokines (IL-1β and TNFα ), one chemokine (IL-8), and one anti-inflammatory cytokine (IL-10) were cloned, sequenced, and characterized for the first time in two commercially relevant Perciformes in the Gulf of Mexico, golden tilefish (Lopholatilus chamaeleonticeps) and red snapper (Lutjanus campechanus). The complete amino acid sequence was obtained and confirmed for IL-β and IL-8 from golden tilefish and for IL-8, IL-10, and TNFα from red snapper, with partial sequences obtained for the remaining proteins. The results indicate high homology among Perciformes for all cytokines studied, but divergence with other teleost orders, and low conservation when compared to birds, amphibians, and mammals. The sequences will be used to create a multi-plexed antibody-based assay for the routine detection of cytokines in teleost serum. This would allow the biochemical response to fish health challenges, such as oil spills and other contamination events, to be monitored at the protein level, building upon the current regime of genetic biomarkers. Thus, this work will aid in the understanding of how oil spills and other contamination events may alter the immune response in fishes.

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