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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.
11

Economic analysis of the Florida Everglades restoration

Czajkowski, Jeffrey Robert 21 November 2003 (has links)
An economic valuation methodology was developed in order to monetarily quantify the benefits resulting from the Indian River Lagoon - South (IRLS) $995 million Everglades restoration project. Service flows of the IRLS were identified and their associated economic baseline values were estimated utilizing existing research. A water quality baseline for the IRLS was also established and compared with the best available standards. Benefits accruing beyond the baseline values given the completion of the IRLS restoration were estimated via benefit transfer to be approximately $159 million annually, importantly factoring in the established IRLS water quality baseline. Given these benefit results of a lower bound estimate, the project was determined not to be economically feasible, i.e., NPV < $0, via a cost-benefit analysis. However, Monte Carlo analyses provided further insights into the probability of an economically feasible restoration (36%) given the uncertainty surrounding the benefit estimation, as well as specific variables to focus on to improve this probability. This research highlights the potential significant economic value of the IRLS and the importance of properly estimating this value given the magnitude of costs.
12

Effects Of Petroleum Hydrocarbons On Salt Marsh Communities

Hershner, Carleton H., Jr. 01 January 1977 (has links) (PDF)
This dissertation is from the Joint Program Degree from the College of William & Mary and University of Virginia and awarded by the University of Virginia. The effects of petroleum hydrocarbons on salt marsh grasses and gastropods were examined under three different circumstances. In the first study reported, a small pocket marsh was repeatedly dosed with small amounts of a No. 2 fuel oil. The second study investigated the effects of a large accidental spill of No. 6 fuel oil. The third study involved single doses of a fresh and a weathered crude oil on artificially enclosed segments of marsh.
13

Using indicators for improving the performance of integrated coastal management efforts towards a common framework /

Belfiore, Stefano. January 2005 (has links)
Thesis (Ph.D.)--University of Delaware, 2005 . / Principal faculty advisor: Biliana Cicin-Sain, College of Marine Studies. Includes bibliographical references.
14

Carbon cycling in the York River Estuary: an isotopic and mass balance approach using natural Carbon-14 and Carbon-18 isotopes

Linebaugh, Donald W. 01 January 1999 (has links)
No description available.
15

Are We Providing Preferred Floral Resources for Bees in Our Neighborhoods?: Assessing the Relationship Between Small Scale Vegetation Metrics and Bee Presence in SE Portland

Wallace, Hailey 12 July 2019 (has links)
Bee pollinators can thrive in highly urbanized environments if their preferred floral resources and habitat types are available. Enhanced pollinator habitats are being created globally, with a large local effort in Portland, Oregon. This project determined if we were providing the most preferred floral resources at enhanced pollinator sites for bees, if floral resources were available throughout the season, and if differences in dietary preferences between native and honey bees would allow for the identification of "native bee floral resources" in South East Portland. Bee pollinators were monitored from June to August at three enhanced pollinator sites in South East Portland, Oregon. A total of 566 individual bees were observed, tiny dark bees and bumblebees composed the large majority of the urban bee composition. Vegetation metrics and bee presence were correlated using a Generalized Linear Mixed Model and significant variables that predicted bee presence included Solidago canadenisis (p-value 0.0024), density of floral resources (p-value
16

Seasonal Variations in Fish Assemblages of Small Warmwater Streams in Four Southeastern National Parks

Zimmerman, Joseph Carl 01 May 2007 (has links)
Small warm-water streams in the southeastern United States experience significant differences in temperature, as well as changes in physical parameters due to seasonal fluctuations. It has been generally thought that fish assemblage patterns change as a direct result of these seasonal variations. This study was designed to determine the effects of variable flow regimes on fish species composition, diversity, and abundance. Eight small warm-water streams in four national parks (Chickamauga and Chattanooga National Military Park, Fort Donelson National Battlefield, Abraham Lincoln Birthplace National Historic Site, and Russell Cave National Monument) were sampled May-June 2005 for the summer trials, October-November 2005 for the fall trials, and April 2006 for the spring trials. All trials were conducted when water levels and flows were at normal seasonal stages. Fish populations were determined by electrofishing a 100-m reach at each site. Physical parameters including temperature, dissolved oxygen, conductivity, pH, and flow rate were also measured at each site. From summer to fall, the majority of the streams decreased in flow until temporary pools were formed. The lack of flow caused increased temperatures, decreased dissolved oxygen, and increased conductivity levels. As a direct result, overall fish abundance and diversity values decreased. From fall to spring, all the streams increased in flow, which brought back the riffle to pool habitat sequences. Dissolved oxygen levels increased, conductivity levels decreased, and temperatures became more stable. As a result, overall fish abundance and diversity values increased. Results indicated that fish assemblage patterns in the four parks did change as a direct result of the seasonal variations in habitat and water quality.
17

Beyond Indicators and Reporting: Needs, Limitations and Applicability of Environmental Indicators and State of the Environment Reporting

Da Silva, Sarah Elizabeth 13 January 2010 (has links)
This research examines the perceptions and use of environmental indicators and state of the environment reports by local government and Conservation Authority decision makers and practitioner’s within the Ontario portion of the Great Lakes and St. Lawrence basin. Participants describe their information needs and how indicators and SOER are used at the local level; and what limitations or challenges they face to bridge the gap between monitoring information and policy. A multi-method approach including a web-based survey and follow-up telephone interviews was the primary data collection method used. Indicator and SOER knowledge and information are further explored to determine information exchange amongst different levels of governance. To review the dissemination of indicator and SOER information from a higher spatial scale down to the local level, the State of the Great Lakes environmental indicators and SOER, developed by the governments of Canada and the United States served as a case study.
18

Beyond Indicators and Reporting: Needs, Limitations and Applicability of Environmental Indicators and State of the Environment Reporting

Da Silva, Sarah Elizabeth 13 January 2010 (has links)
This research examines the perceptions and use of environmental indicators and state of the environment reports by local government and Conservation Authority decision makers and practitioner’s within the Ontario portion of the Great Lakes and St. Lawrence basin. Participants describe their information needs and how indicators and SOER are used at the local level; and what limitations or challenges they face to bridge the gap between monitoring information and policy. A multi-method approach including a web-based survey and follow-up telephone interviews was the primary data collection method used. Indicator and SOER knowledge and information are further explored to determine information exchange amongst different levels of governance. To review the dissemination of indicator and SOER information from a higher spatial scale down to the local level, the State of the Great Lakes environmental indicators and SOER, developed by the governments of Canada and the United States served as a case study.
19

Seasonal Variations in Fish Assemblages of Small Warmwater Streams in Four Southeastern National Parks

Zimmerman, Joseph Carl 01 May 2007 (has links)
Small warm-water streams in the southeastern United States experience significant differences in temperature, as well as changes in physical parameters due to seasonal fluctuations. It has been generally thought that fish assemblage patterns change as a direct result of these seasonal variations. This study was designed to determine the effects of variable flow regimes on fish species composition, diversity, and abundance. Eight small warm-water streams in four national parks (Chickamauga and Chattanooga National Military Park, Fort Donelson National Battlefield, Abraham Lincoln Birthplace National Historic Site, and Russell Cave National Monument) were sampled May-June 2005 for the summer trials, October-November 2005 for the fall trials, and April 2006 for the spring trials. All trials were conducted when water levels and flows were at normal seasonal stages. Fish populations were determined by electrofishing a 100-m reach at each site. Physical parameters including temperature, dissolved oxygen, conductivity, pH, and flow rate were also measured at each site. From summer to fall, the majority of the streams decreased in flow until temporary pools were formed. The lack of flow caused increased temperatures, decreased dissolved oxygen, and increased conductivity levels. As a direct result, overall fish abundance and diversity values decreased. From fall to spring, all the streams increased in flow, which brought back the riffle to pool habitat sequences. Dissolved oxygen levels increased, conductivity levels decreased, and temperatures became more stable. As a result, overall fish abundance and diversity values increased. Results indicated that fish assemblage patterns in the four parks did change as a direct result of the seasonal variations in habitat and water quality.
20

Assessing the Persistence and Multiplication of Fecal Indicator Bacteria in Hawai'i Soil Environment

Byappananhalli, Muruleedhara N 12 1900 (has links)
Traditional fecal indicator bacteria such as fecal coliform, E.coli and enterococci have been shown to be unreliable indicators of the hygienic quality of recreational waters under tropical conditions. One of the major reasons for considering these bacteria as ineffective indicators of water quality in warm, tropical regions is that they are consistently found in natural environments (plants, soil, water) in the absence of any significant contamination of these environments. Since preliminary studies conducted in Hawaii had indicated soil as the major environmental source of elevated concentrations of these bacteria in environmental waters, the aim of this study was to focus on the soil environment to specifically address two assumptions made by regulatory agencies in using fecal bacteria as indicators of water quality: first, there should not be an environmental source of these indicator bacteria unrelated to sewage or fecal matter contamination, and second, the indicator bacteria do not multiply in the environment. To determine the validity of these two assumptions under tropical conditions in Hawaii and possibly other tropical locations, various experiments were conducted. The major findings are as follows. 1) Analysis of soil samples collected from various locations representing major soil groups on the island of Oahu showed that fecal indicator bacteria are naturally found in most of the soil environments, indicating that the fecal bacteria have adapted to the soil conditions to become part of soil biota. 2) Evidence was obtained to show that the soil contains adequate nutrients to sustain the populations of these bacteria. 3) Growth and multiplication of fecal indicator bacteria in natural soil was dependent on available nutrients (particularly carbon), moisture and competing microorganisms. In conclusion, tropical soil conditions are suboptimal for the multiplication of fecal indicator bacteria. Consequently, these bacteria in natural soil conditions will probably grow and multiply sporadically when conditions are relatively optimal. Although concentrations of fecal indicator bacteria in soil represent only a small fraction of the microbiota, their counts are significant enough in numbers not only to impact the quality of recreational waters but also to nullify two of the assumptions used in the application of recreational water quality standards. Thus, there is a need for an alternate and more reliable indicator of water quality in Hawaii and other tropical locations. / Department of Health, State of Hawaii; US Environmental Protection Agency

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