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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.
51

Impacts and Recovery of the Deepwater Horizon Oil Spill on Vegetation Structure and Function of Phragmites Australis

Judy, Chad Robert 20 June 2013 (has links)
Abstract The aim of this study was to determine the impacts of the Deepwater Horizon (DWH) oil spill on the common reed Phragmites australis, and the processes controlling species effects and recovery, via a greenhouse mesocosm study. In the greenhouse DWH source oil, weathered approximately 40% by weight and emulsified, was applied to the aboveground shoots of P. australis growing in marsh sods to produce the following treatment-levels: (1) oil coverage of the lower 30% of shoot-height, (2) the lower 70% of shoot-height, (3) repeated oil coverage of the lower 70% of shoot-height, (4) 100% oil coverage of shoots, (5) oil applied to the soil at a rate of 8 L m⁻², and (6) unoiled controls. I quantified a strong resilience of P. australis when oil was applied only to aboveground biomass, with negative impacts becoming apparent when oil was added to the soil profile. The Total biomass and stem cumulative length were both impacted by the addition of 8 L m⁻² of weathered DWH source oil to the soil profile. Due to the apparent negative results of adding oil directly to the soil, a second experiment was designed to better understand impacts from soil oiling. Aboveground biomass was harvested from the sods that had received only shoot oiling and allowed to regrow for two months, at which point weathered DWH source oil was applied to the marsh sods at rates of (1) 0 L m⁻² (control), (2) 4 L m⁻², (3) 8 L m⁻², (4) 12 L m⁻², and (5) 16 L m⁻². This experiment verified that increased oiling to the soil profile increased negative impacts to P. australis, reducing stem cumulative length, aboveground biomass, and belowground biomass at the highest oiling rates. Higher oiling doses resulted in higher rates of soil respiration and reduced soil Eh. Based on my research, complete mortality of P. australis is unlikely from exposure to weathered and emulsified DWH source oil. However, vertical growth, above and belowground biomass, and other plant processes will be impacted, with oiling to the soil having much greater impact than oiling to the aboveground shoots.
52

Leadership in Environmental and Energy Design: A True Sustainable Development Model?

Loser, Christopher Jay 10 April 2013 (has links)
Suburban sprawl and sustainable development has received increasing worldwide attention over the past few decades. In 1998, sustainable development principles were codified in the Leadership in Energy and Environmental Design (LEED) certification system. The most recent LEED certification system to be released, LEED for New Development (LEED-ND), includes sustainable development goals with the addition of smart growth principles intended to curb sprawl. This study examines and evaluates LEED-ND in order to determine if it meets the requirements of sustainable development to provide for the needs of future generations, as defined by the United Nations World Commission on Environment and Development. It also analyzes certified LEED-ND projects to determine which portions of the rating system were utilized the most, and least, frequently, and provided recommendations for future LEED-ND revisions. The study found that, while LEED-ND does promote most long-term sustainable development goals, it focuses more upon climate change and social equity than it does in combating sprawl and its environmental impacts. However, its inflexible and exclusory nature prevent many sustainable development goal from being fulfilled, and its use of double-counting credits exaggerates its sustainable development achievements.
53

Renewable Energy Across the 50 United States and Related Factors

Christenson, Cynthia Brit 25 January 2013 (has links)
Renewable energy production replaces diminishing non-renewable energy sources including fossil fuels. Major sources of renewable energy include biofuels, geothermal, hydroelectric, solar thermal and photovoltaic, wind, wood, and biomass. Greater use of renewable energy sources can fill gaps in energy as non-renewable sources are depleted, provide more energy independence at a state and national level, and help address climate change by reducing greenhouse gas emissions from combustion of fossil fuels. The research objectives of this thesis are two-fold. First, which U.S. states are leaders in renewable energy production? Second, what factors may account for variation among U.S. states in levels of renewable energy production? The five state leaders in production of renewable energy are Washington, California, Iowa, New York, and Texas. Potential influences on renewable energy production include these factors: total energy importation or exportation by state, education level of residents, retail electricity cost, gross state product, poverty level, total population, along with indicators of political and religious ideology including Republican presidential voting, belief in God, and renewable energy potential. A Pearson correlation analysis was conducted to identify multi-collinearity between the independent variables and a factor analysis was used to explore possible associations between all variables. Finally, linear regression analysis is conducted to identify those independent variables significantly associated with the dependent variable, renewable energy production levels for each state. Factors found to be associated with higher renewable energy production are a larger state economy as measured by higher gross state product (GSP) and greater renewable energy potential. The analysis yields insights into the conditions under which U.S. states are more likely to produce higher levels of renewable energy, relevant information for state and federal planning for increased energy independence and greenhouse gas reduction.
54

Measuring City Commitment to Climate Change Mitigation

Clinton, Kelsey Wefer 04 May 2012 (has links)
An increasing number of cities are focusing on sustainability and climate change mitigation by joining groups such the International Council for Local Environmental Initiatives (ICLEI). ICLEI uses a five-step milestone process to help cities achieve their mitigation goals. These milestones include conducting a greenhouse gas inventory, setting reduction targets, creating a Climate Action Plan, and implementing and monitoring that plan. Prior studies have examined factors that may influence a citys decision to join ICLEI, but few have looked at how committed the cities are to sustainability and to ICLEI itself after joining the organization. The purpose of this study is to uncover why some member cities show a greater commitment to the ICLEI program than others. Commitment to climate change mitigation was measured by the number of ICLEI program milestones achieved by 257 member cities. Fifteen independent variables covering socioeconomic conditions, local residents attitudes, climate stress, and location were included in a principal components analysis, chi-square test, and multiple regression analysis to identify key factors that may explain variation in level of commitment to climate change mitigation. The results show that the number of years a city has been an ICLEI member has a positive effect on milestone attainment, while the levels of car dependency and hazardous air pollutants have negative effects. In other words, member cities with higher levels of hazardous air pollution and greater dependence on automobiles had achieved fewer ICLEI milestones than cities with lower levels of climate stress. These findings are useful not only in evaluating the effectiveness of ICLEI, but in yielding better understanding of the varied environmental, cultural and socioeconomic contexts of member cities. The insights have implications for ICLEI and other similar organizations that may need to target member cities facing more significant challenges in meeting program goals with additional technical assistance and support to help them achieve meaningful local climate change mitigation.
55

The Ecological Impact of the Deepwater Horizon Oil Spill on Vibrio Parahaemolyticus Type III Secretion System and the Vibrio Community

Stephens, Erica L. 30 April 2012 (has links)
Vibrio spp are gram-negative, halophilic bacteria that naturally occur in both shallow coastal waters and parts of the deepest oceans and are a known human pathogen. There have not been extensive studies that analyze an oil spill as an environmental stressor to vibrios. If there were to be an increase in the pathogenicity of vibrios it would be a cause for human health concern. The purpose of the two studies presented was to determine changes in the pathogenicity of V. parahaemolyticus pathogenicity and the vibrio community, with respect to V. cholera, V. parahaemolyticus, and V. vulnificus. The results showed that there was an insignificant change in V. parahaemolyticus pathogenicity, and there was not a significant trend in the species composition of the vibrio community when interacting with oil. Even though the results did not show statistically significant or consistent trends of both studies, the study was an innovative evaluation of the vibrio community and various oil concentration effects thereon.
56

Composition and Physiological Characteristics of the University Lake Ecosystem Phytoplankton Community: Impacts of Seasonal and Episodic Events

Norris, Brianne Elizabeth 19 June 2012 (has links)
This research determined the changes in phytoplankton community composition in a shallow subtropical lake, influenced by urban surroundings. Specifically this research focused on the effects of seasonal progression and episodic events on the changing inorganic nutrient dynamics and the effects those dynamics had on the phytoplankton community composition and productivity. This research quantified gross primary production and respiration to determine if seasonality or episodic events were acting as forcing functions of the phytoplankton community composition. Water samples were collected weekly at three sites on the lakes perimeter, as well as following episodic events, to monitor nitrate (NO3), phosphate (PO4-3), ammonium (NH4), and silicate (Si) concentrations, and diagnostic pigment concentrations. Gross primary production and respiration was measured following a four-hour incubation period. Results show that seasonality was not significant in affecting the inorganic nutrient concentrations, but episodic events were significant in influencing the concentrations of NO3 and PO4-3. Gross primary production existed at a mean rate of 3.45 gram carbon/gram chlorophyll a/ hour (g C/g chl/hr), and the median respiration rate was 0.66 g C/g chl/hr. Primary production and respiration were not significantly affected by seasonal progression, but gross assimilation of oxygen was significantly increased following episodic events, and increases were dependent on the presence of phosphate and ammonium. The phytoplankton community composition was determined to be 51% chlorophyceae, 30% cyanobacteria, 10% diatoms, and 3.4% cryptophyceae, Chlorophytes and diatoms significantly affected by seasonality and episodic events, but only at particular test sites, and the cyanobacteria and diatom populations experience a negative linear growth relationship with one another. The changes in community composition were the result of both seasonality and episodic events, and fluctuations of ammonium and phosphates, while productivity was influenced solely by the occurrence of episodic events. Low biodiversity within the phytoplankton community exists in this lake as a result of urban runoff and eutrophication.
57

THE CONTEXT OF PUBLIC ACCEPTANCE OF HYDRAULIC FRACTURING: IS LOUISIANA UNIQUE?

White, Crawford 16 July 2012 (has links)
Hydraulic fracturing has received increased attention over the past decade. The rapid adoption of this technique coupled with accurate directional horizontal drilling has unlocked several US shale formations. Amid the possibility of 100% domestically sourced natural gas, public perception varies and opponents question the long-term risks and repercussions of the technique. This thesis will provide context to some of the variation seen in the public perception of hydraulic fracturing among three states: Louisiana, Pennsylvania, and Texas. Two surveys of Louisiana stakeholders were conducted in order to rank the state in terms of acceptance amongst previously conducted surveys of its two peers. Results show that of the three states, Louisianans have accepted hydraulic fracturing the most and Pennsylvanians the least. Factors have been identified that may explain differences in acceptance among these states. These include well densities, potentially affected populations, previous environmental contamination experiences, variations among state regulatory response, and the personal histories and experiences of each states populations. Louisianas unique history with oil and gas, high exposure to energy development, and vital role in the United States energy market may all be contributing factors for the acceptance of hydraulic fracturing and horizontal drilling of shale as reasonable practices. Meanwhile, the increased frequency of fracking accidents and negative portrayal in documentaries may both contribute to Pennsylvanias low rate of acceptance.
58

An Analysis of the Allocation of FEMA Public Assistance Funds Along the U. S. Gulf Coast Following Hurricanes Katrina, Rita, and Wilma

Golden, Pamela Camille 18 April 2013 (has links)
Due to the effects of global climate change, natural disasters such as hurricanes are increasing in terms of both intensity and frequency. During the record-breaking hurricane season of 2005, Hurricanes Katrina, Rita, and Wilma struck the U. S. Gulf Coast, affecting areas from Texas to Florida and causing billions of dollars in damage. This study examines the allocation of FEMA Public Assistance across the affected Gulf of Mexico states, what factors account for variation in in assistance allocation, what are the priorities for recovery among county leaders and what obstacles they have encountered since 2005. This study includes 136 counties and seven independent variables. The analysis includes bivariate correlation and multiple regression analysis, and a brief survey that was sent out to the Emergency Management Agency Director in each county of the study area. The results show that the level of damage and amount of poverty within a county were strong predictors of Public Assistance allocation. Debris Removal and Infrastructure projects were the highest overall priority for communities and the most common obstacle faced by the local government was difficulty in getting a firm commitment from FEMA regarding the eligibility of a project. These results have important implications for future disaster management that will face ever-evolving risks.
59

Inductively Coupled Plasma Optical Emission Spectroscopy Analysis of Heavy Metal Concentrations in Gulf Menhaden (Brevoortia patronus) Populations in the Northern Gulf of Mexico from 2011 to 2012

Rockett, Hannah Paula 03 July 2013 (has links)
In 2010, the Deepwater Horizon (DWH) oil spill, released 4.9 million barrels of oil into the Gulf of Mexico, creating the largest marine oil spill in the history of the U.S. petroleum industry. Trace metals, including those from crude oil, were dispersed in the water column and bound to suspended particulates. As obligate filter-feeding omnivores and a predominate fishery in the Gulf of Mexico, Gulf menhaden (Brevoortia patronus) are susceptible to trace metal accumulation. Samples of menhaden were collected at two locations in coastal Louisiana, Grand Isle (GI) and Vermillion Bay (VB), with VB serving as the non-impacted DWH oil spill site and GI as the impacted DWH oil spill site. The analysis of trace metals was performed using inductively coupled plasma-optic emission spectroscopy (ICP-OES) methods. Eleven metals (As, Ba, Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn, V) were chosen and observed by four variables: place (VB or GI), size (small or large), month (July, August or September), and year (2011 or 2012) and the interactions between the variables. Metal concentrations in the current study followed the sequence: Fe > Zn > Ba > As > V > Cr > Cu > Ni > Pb > Co > Cd. Results showed that in 2011, VB had statistically higher concentrations than GI for 9 of the 11 metals. Elevated discharge rates during the Mississippi River Flood of 2011 produced a dilution effect, decreasing the concentration of trace metals in the water column at GI. Size was also significant, with small fish having statistically higher concentrations for 8 of the 11 metals. In fish, younger/smaller fish have higher metabolic activities than older/larger fish, which leads to a higher metal accumulation in smaller fish. Arsenic was the only metal that had higher concentrations in 2011 and in large fish. Differences in arsenic trends may be attributed to the DWH oil spill, which may have caused reduced adsorption of arsenic by the mineral goethite and increased concentrations of arsenic in the water. Iron and zinc in the current study exceeded the FAO/WHO maximum permissible limit.
60

Community Resilience to Coastal Hazards: An Analysis of Two Geographical Scales in Louisiana

Li, Chi 12 July 2013 (has links)
Quantifying resilience is difficulties due to the different definitions of resilience, the interchangeable uses with two other terms vulnerability and adaptability, as well as the lack of consensus on what indicators should be selected to quantifying resilience. This thesis research studied the community resilience in Louisiana by applying the Resilience Inference Measurement (RIM) model at two geographic levels: county level and zip code level. The RIM model accesses resilience by using three dimensions (exposure, damage, and recovery) and two abilities (vulnerability and adaptability). The types of coastal hazards included in this study were: coastal, flooding, hurricane/tropical storm, tornado, and severe storm/thunder storm. The study time period was 2000 to 2010. K-means clustering analysis was used to derive the resilience groups. Discriminant analysis was applied to validate the resilience rankings by using a set of indicator variables. At the county level, discriminant analysis yielded a remarkably high 93.8% classification accuracy when population growth rate in 2000-2010 was used as a recovering indicator and 28 adaptability variables were used to characterize the counties. The accuracy at the zip-code level decreased to 80.2% when population growth rate was used as a recovering indicator. In general, the findings at two different scales are consistent; counties and zip codes with higher socioeconomic status and more resources were found to be more resilient. Interestingly, the three most potent indicators revealed at both scales were the same, which are median rent, median value of owner-occupied housing units and housing density. These findings support the use of the RIM model to further explore adaptability indicators and the underlying process leading to resilience.

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