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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

Entangled Eden: ecological change and the Lake Huron Commercial Fisheries, 1835-1978

LaCombe, Kent January 1900 (has links)
Doctor of Philosophy / Department of History / James E. Sherow / This project examines ecological change in Lake Huron during the nineteenth and twentieth century and investigates the causative role of the commercial fisheries in that change. The repeated failures of various regional and international efforts designed to improve management of the lake’s fisheries are also examined. The fundamental argument is that economic considerations were the primary motivations for policy development related to the Great Lakes fisheries. Historically management programs and legislation were shaped by local and regional economic interests. The central focus of this project is Lake Huron. Anthropogenic changes in that lake’s environment dramatically affected the lives and relationships of its non-human inhabitants. The same changes also transformed relationships among human beings who relied on the lake’s resources. Commercial fishermen who operated in the waters of both the United States and Canada relied on the lake for their livelihood, but as the twentieth century commenced the supply of marketable fishes decreased. Competition accelerated and fishermen introduced new technologies and increased their quantity of fishing gear in an effort to maximize their catches in response to fluctuating returns. Economic considerations were of primary concern to both fishermen and government bureaucrats. Lake Huron’s status as an international borderland further complicated the situation. Analysts in both the United States and Canada recognized the dramatically changing conditions of the lakes as reflected through the woes of the commercial fishery. Nonetheless, the germane state, provincial and national governments repeatedly failed in their attempts to develop a cooperative management plan. By the second half of the twentieth century Lake Huron’s embattled biome stood in stark contrast to the once seemingly endless numbers of fishes and flora that sustained the lake’s web of life for hundreds of years.
32

Modelling Waves and Currents in Northeastern Lake Ontario to Assess the Impacts of a Proposed Offshore Wind Farm

McCombs, Matthew 02 October 2013 (has links)
A spectral wave model (SWAN) coupled with a depth averaged hydrodynamic model (Delft3D) was used to understand the wave and flow dynamics of the Kingston Basin of Lake Ontario during large winter storm events. This model was then used to assess the impact of an offshore wind farm in the Kingston Basin. Results over different model domains with various forcing methods were compared to achieve the highest correlation with wave, current and water level observations from several locations. Storm events were modelled over the complex bathymetry of the basin and results were verified using wave and current profiler data collected during the winters of 2009-10 and 2011-12. Waves were composed of both locally generated wind sea and swell from the main basin of Lake Ontario, while flows throughout the Kingston Basin showed a complex circulation pattern. This circulation is composed of several wind-driven gyres, which are magnified during storm events. The impact of waves on the circulation patterns within the basin is highest in shallow areas where wave breaking drives circulation. To simulate a wind farm, a transmission coefficient was used in the wave model to represent the effects on waves, and an energy loss term was added to the hydrodynamic momentum equations to represent the added drag of the piles on the circulation. The results indicate that the coastal areas in eastern Lake Ontario will be minimally affected. The headlands of Big Sandy Bay, Wolfe Island, could see the largest coastal effects with changes in significant wave height predicted to be < 2%. The majority of impacts to circulation occur in the near-field, with changes in current magnitude of < 0.08 m s-1 (up to 50%). Areas near Wolfe Island exhibit changes of ~ 0.05 m s-1 (30 %), although overall circulation patterns throughout the basin are not affected. The majority of changes to surface waves and wind-driven currents are due to wind farm position with respect to wind direction and the re-direction of flows and waves as they pass through the wind farm. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-09-30 09:30:01.042
33

The Importance of Thermal Habitat Quality for Pumpkinseed (Centrarchidae: Lepomis gibbosus) in Small and Constructed Coastal Embayments Along the Northwest Shoreline of Lake Ontario

Murphy, Shidan 11 January 2012 (has links)
Along the Toronto shoreline, small coastal embayments (0.4 – 32 ha) are being constructed or modified to restore warmwater fish habitat. I describe how Lake Ontario (hereafter the Lake) alters the thermal regime of these small coastal embayments, how the altered thermal regimes affect growth and survival of age-0 warmwater fishes, and how the thermal habitat quality for such fishes can be improved by altering embayment design. During the warming period of the ice-free season, embayments warm faster than the Lake and so are cooled by exchanges with the Lake. Later in the year Lake exchange warms the rapidly cooling embayments, but the net effect of Lake-embayment exchange is cooling. The degree of cooling in Toronto’s small coastal embayments varies; many have temperatures near that of the Lake, and a few warm as much as local ponds. Age-0 pumpkinseed (Lepomis gibbosus) can fail to reach sufficient size to survive the winter in cooler embayments because their spawning is delayed and their growth is slowed. Most embayments along the Toronto shoreline are too cold to produce age-0 fish that can survive the winter, but all embayments are occupied by age >1 pumpkinseed, suggesting movement from warmer to cooler embayments. Using otolith microchemistry to identify natal embayments of fish, I confirm that age-0 and age-1 pumpkinseed, as well as age-0 largemouth bass (Micropterus salmoides) and age-0 yellow perch (Perca flavescens), exist in metapopulations. Embayment bathymetry is a poor predictor of temperature because almost all embayment flushing rates are very fast, usually 1-2 days. Warmer embayments are located in protected areas of Lake Ontario and receive waters that have already heated substantially. Cold embayments are located along the exposed shoreline of Lake Ontario. To protect embayments from cold lake waters, the cross-sectional area of embayment channels need to be reduced to 1-10% of their current size.
34

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.
35

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.
36

The Importance of Thermal Habitat Quality for Pumpkinseed (Centrarchidae: Lepomis gibbosus) in Small and Constructed Coastal Embayments Along the Northwest Shoreline of Lake Ontario

Murphy, Shidan 11 January 2012 (has links)
Along the Toronto shoreline, small coastal embayments (0.4 – 32 ha) are being constructed or modified to restore warmwater fish habitat. I describe how Lake Ontario (hereafter the Lake) alters the thermal regime of these small coastal embayments, how the altered thermal regimes affect growth and survival of age-0 warmwater fishes, and how the thermal habitat quality for such fishes can be improved by altering embayment design. During the warming period of the ice-free season, embayments warm faster than the Lake and so are cooled by exchanges with the Lake. Later in the year Lake exchange warms the rapidly cooling embayments, but the net effect of Lake-embayment exchange is cooling. The degree of cooling in Toronto’s small coastal embayments varies; many have temperatures near that of the Lake, and a few warm as much as local ponds. Age-0 pumpkinseed (Lepomis gibbosus) can fail to reach sufficient size to survive the winter in cooler embayments because their spawning is delayed and their growth is slowed. Most embayments along the Toronto shoreline are too cold to produce age-0 fish that can survive the winter, but all embayments are occupied by age >1 pumpkinseed, suggesting movement from warmer to cooler embayments. Using otolith microchemistry to identify natal embayments of fish, I confirm that age-0 and age-1 pumpkinseed, as well as age-0 largemouth bass (Micropterus salmoides) and age-0 yellow perch (Perca flavescens), exist in metapopulations. Embayment bathymetry is a poor predictor of temperature because almost all embayment flushing rates are very fast, usually 1-2 days. Warmer embayments are located in protected areas of Lake Ontario and receive waters that have already heated substantially. Cold embayments are located along the exposed shoreline of Lake Ontario. To protect embayments from cold lake waters, the cross-sectional area of embayment channels need to be reduced to 1-10% of their current size.
37

Traditional Methods and New Fluorometric Methods to Determine Phytoplankton Nutrient Status for Freshwater Ecosystems, and Their Application in the Lower Laurentian Great Lakes

Rattan, Kimmy January 2009 (has links)
The Laurentian Great Lakes are the largest system of freshwater on earth containing 22% of the world’s supply. Although part of a single system, each lake shows substantial variation regarding physical, chemical and biological parameters. The main goals of this thesis were to characterize the nutrient status of natural phytoplankton communities while comparing several commonly used measurements of nutrient status and Chlorophyll a (Chl a) fluorescence measurements. The study sites include the western basin (WB), west-central basin (WCB), and central basin (CB) of Lake Erie, the Bay of Quinte in Lake Ontario, and Colpoys Bay in Lake Huron. Independent measures of nutrient status were assessed by measurements of nitrogen (N) debt, phosphorus (P) debt, particulate C:N:P ratios, and alkaline phosphatase activity (APA). Variable fluorescence of chlorophyll a was measured by pulse amplitude modulated (PAM) fluorometry and fast repetition rate (FRR) fluorometry in parallel with the independent measures. In 2005, the phytoplankton communities in Lake Erie were generally N deficient in May, P deficient in June, and neither N nor P deficient in September. The maximum dark adapted quantum yield (Fv/Fm) measured by PAM or FRRF was lower in May and June, and maximal in September, while the functional absorption cross section of photosystem II (σPSII) was maximal in May and June, and minimal in September. Relationships between the variable fluorescence indicators and independent measures of nutrient status showed strong associations with N or P deficient sites having low Fv/Fm and high σPSII. In 2006, the electron transport rate (ETR) and the initial slope (α) derived from the PAM fluorescence rapid light-response curves (RLC) were compared to independent measures and Fv/Fm measurements in Lake Erie. Relationships between ETR, α, independent measures of nutrient status, and Fv/Fm measurements revealed strong associations with nutrient status. Confirming previous reports, N deficiency was highest in the WB during isothermal conditions while P deficiency was highest in the CB during summer stratification. The fluorescence parameters generally decreased as the severity of N and P deficiency increased. N and P enrichment assays also revealed increased values of Fv/Fm, ETR, and α from N and P deficient samples over twenty-four hours. Additionally, spatial variability of P status was evaluated during summer stratification. Colpoys Bay, the most oligotrophic site, had the strongest P deficiency, and evidence for existence of P deficiency was weakest in the Bay of Quinte, the most eutrophic site. Nutrient enrichment assays revealed that all fluorescence parameters showed a positive response to P additions in oligotrophic sites, with no response in eutrophic sites. Community structure was also associated with nutrient status and Chl a fluorescence at all locations. In P deficient sites, nano-flagellates such as chrysophytes and cryptophytes were prevalent; cyanobacteria were dominant at sites that displayed N deficiency.
38

Traditional Methods and New Fluorometric Methods to Determine Phytoplankton Nutrient Status for Freshwater Ecosystems, and Their Application in the Lower Laurentian Great Lakes

Rattan, Kimmy January 2009 (has links)
The Laurentian Great Lakes are the largest system of freshwater on earth containing 22% of the world’s supply. Although part of a single system, each lake shows substantial variation regarding physical, chemical and biological parameters. The main goals of this thesis were to characterize the nutrient status of natural phytoplankton communities while comparing several commonly used measurements of nutrient status and Chlorophyll a (Chl a) fluorescence measurements. The study sites include the western basin (WB), west-central basin (WCB), and central basin (CB) of Lake Erie, the Bay of Quinte in Lake Ontario, and Colpoys Bay in Lake Huron. Independent measures of nutrient status were assessed by measurements of nitrogen (N) debt, phosphorus (P) debt, particulate C:N:P ratios, and alkaline phosphatase activity (APA). Variable fluorescence of chlorophyll a was measured by pulse amplitude modulated (PAM) fluorometry and fast repetition rate (FRR) fluorometry in parallel with the independent measures. In 2005, the phytoplankton communities in Lake Erie were generally N deficient in May, P deficient in June, and neither N nor P deficient in September. The maximum dark adapted quantum yield (Fv/Fm) measured by PAM or FRRF was lower in May and June, and maximal in September, while the functional absorption cross section of photosystem II (σPSII) was maximal in May and June, and minimal in September. Relationships between the variable fluorescence indicators and independent measures of nutrient status showed strong associations with N or P deficient sites having low Fv/Fm and high σPSII. In 2006, the electron transport rate (ETR) and the initial slope (α) derived from the PAM fluorescence rapid light-response curves (RLC) were compared to independent measures and Fv/Fm measurements in Lake Erie. Relationships between ETR, α, independent measures of nutrient status, and Fv/Fm measurements revealed strong associations with nutrient status. Confirming previous reports, N deficiency was highest in the WB during isothermal conditions while P deficiency was highest in the CB during summer stratification. The fluorescence parameters generally decreased as the severity of N and P deficiency increased. N and P enrichment assays also revealed increased values of Fv/Fm, ETR, and α from N and P deficient samples over twenty-four hours. Additionally, spatial variability of P status was evaluated during summer stratification. Colpoys Bay, the most oligotrophic site, had the strongest P deficiency, and evidence for existence of P deficiency was weakest in the Bay of Quinte, the most eutrophic site. Nutrient enrichment assays revealed that all fluorescence parameters showed a positive response to P additions in oligotrophic sites, with no response in eutrophic sites. Community structure was also associated with nutrient status and Chl a fluorescence at all locations. In P deficient sites, nano-flagellates such as chrysophytes and cryptophytes were prevalent; cyanobacteria were dominant at sites that displayed N deficiency.
39

Anthony Wayne: The History and Archaeology of an Early Great Lakes Steamboat

Krueger, Bradley Alan 2012 May 1900 (has links)
The Great Lakes side-wheel steamboat Anthony Wayne was built in 1837 at Perrysburg, OH and participated in lakes shipping during a time when such vessels were experiencing their heyday. Designed as a passenger and cargo carrier, the steamer spent 13 years transporting goods and people throughout the Upper Lakes until succumbing to a boiler explosion while headed to Buffalo on 28 April 1850. The remains of Anthony Wayne were discovered in 2006 and two years later a collaborative project was begun for the purposes of documenting and assessing the present day condition of the wreck. Anthony Wayne is the oldest steamboat wreck on the Great Lakes to be studied by archaeologists and represents an important piece of maritime heritage that can aid researchers in understanding architectural and machinery specifics that are unknown to us today. This thesis presents the results of an archaeological and archival investigation of Anthony Wayne. Information pertaining to the discovery and significance of the vessel are presented, followed by descriptions of Perrysburg and its shipping industry, the steamer's owners, and how the vessel was built. The operational history of Anthony Wayne is then outlined chronologically, including ports of call, cargoes, masters, and incidents the steamer experienced. Details of the explosion and the aftermath of the sinking are then discussed, followed by a brief summary of other Great Lakes steamboat catastrophes from 1850 and why boilers explode. Focus then shifts to the two-year archaeological investigation, including project objectives, methodology, and findings. The construction specifics of the steamboat's hull, drive system, and associated artifacts are then presented, followed by post-project analysis and conclusions. A catalog of Great Lakes steam vessels, vessel enrollment documentation, the coroner's inquest following the disaster, and the initial dive report from the discoverers are furnished as appendices.
40

What is the academic review process and how is it working at the Naval Hospital Corps School /

Adams, Sonia I. Worley, Timothy B. January 2004 (has links) (PDF)
Thesis (M.B.A.)--Naval Postgraduate School, June 2004. / Thesis advisor(s): Alice M. Crawford, Susan P. Hocevar, Philip J. Candreva. Includes bibliographical references (p. 87-88). Also available online.

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