This thesis explores the feeding habits of sunfish and bluegill in Texas lakes. Data gathered for this study is aimed to aid conservation of these pan fish by making a contribution toward a greater life history understanding of each species.

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This study was designed with the overriding goal of improving our understanding of the nature, causes, and impacts of past climatic conditions in the High Arctic and to evaluate the potential impacts of future climatic warming. Specifically, the focus of this project was centered on Upper and Lower Murray Lakes (81° 21’ N, 69° 32’ W) on northern Ellesmere Island, Nunavut, Canada. Sediment cores were collected from each of the lakes in order to reconstruct past climate and environmental variability and space-borne synthetic aperture radar (SAR) data were used to evaluate recent variability in the ice cover of these lakes. The climatic setting and physical characteristics of Lower Murray Lake has led to the formation and preservation of annually laminated sediments (varves). Varve deposition began ca. 5200 calendar years BP and continued through 2004 AD, providing an annual record of sediment accumulation spanning the past 5200+ years. Annual mass accumulation was correlated to regional July temperatures providing a means of quantitatively evaluating past temperature changes in the region. The temperature reconstruction suggests that recent temperatures are ~2.6°C higher than minimum temperatures observed during the Little Ice Age, maximum temperatures during the past 5200 years exceeded modern values by ~0.6°C, and that minimum temperatures observed approximately 2900 varve years BC were ~3.5°C colder than recent conditions. SAR observations of the ice cover Upper and Lower Murray Lake were used to assess the potential effects of past and future temperatures on lake-ice conditions. Under current climatic conditions the lakes average several weeks of ice-free conditions in August and early September, although in some years a continuous ice cover persists throughout the year. The relationship between summer temperature and ice melt at the lakes suggests that recent warming in the High Arctic has forced the lakes across a threshold from a state of perennial ice cover to seasonal melting. Projected future warming will significantly increase the duration of ice free conditions on Upper and Lower Murray Lakes. Ice-out is predicted to occur between 6 and 28 days earlier for every 1°C of warming.

<p> During the summer of 1970 a study was initiated to define factors controlling the biosphere in the lentic environment of the Precambrian Shield. Data were collected from nine lakes of varying size and depth located in a number of geological formations. Chemical, physical and biological conditions in these lakes were investigated at two sampling periods and the lakes were classified on the basis of morphology (surface area to volume area) and lithology (surficial and bedrock geology). Attempts were made to determine the influence of morphology and lithology on the chemical and biological conditions observed. Emphasis was placed on the relationships of these factors to aspects of the primary and secondary trophic levels in the lentic ecosystem including primary productivity and the standing crop and diversity of phytoplankton and zooplankton.</p> <p> The atmosphere, a third potential factor influencing lakes was investigated by means of a network of air monitoring stations (collecting both precipitation and 'dry fallout') located throughout the greater Sudbury area.</p> <p> The results of the study indicated that: 1. the lentic ecosystem in the Precambrian Shield area studied can be defined by simple chemical and physical variables. 2. the morphology of the lake basins (surface area to volume ratio) modified by lithology (primarily the presence or absence of limestone) is the major factor influencing biological activity. Lakes with a low surface area to volume ratio showed low productivity while lakes with a high surface area to volume ratio showed nigh productivity. Silica and calcium concentrations (influenced by the lithosphere) were important since relatively small changes in the concentration of these chemical species stimulated a response in the biosphere. 3. some of the lakes were affected by concentrations of sulphates conveyed to the water by the atmosphere. Observed effects included increases in the hydrogen ion concentration in lakes with low calcium concentrations (poorly buffered) and a depression of the diversity of both primary and secondary trophic levels.</p> / Thesis / Master of Science (MSc)

In its 2012 National Lakes Assessment, the EPA determined that nutrients are the most widespread stressor of US Lakes, with one-third of US lakes containing excess nitrogen and/or phosphorus. In response, states are developing numeric nutrient criteria to regulate the allowable amount of nutrients in surface waterbodies. In this study, we estimate the recreational value of improved water quality as a result of reduced nutrients in Mississippi lakes using a travel cost model. A major challenge, however, is the lack of water quality data for many Mississippi lakes. We introduce a water quality prediction model to impute water quality measures for lakes that lack water quality data. We compare welfare estimates from travel cost models based on the limited available water quality data to models using predicted water quality measures to evaluate the extent to which inadequate data affects welfare estimates for improved water quality.

An estimate was made to determine the amount of nitrate and phosphate entering Utah Lake in 1968. To make this estimate, the flow data for 1968 and the nitrate and phosphate concentrations for 1970 were used. This was done because of the lack of information. The results show that the total nitrate added to Utah Lake in 1968 was 7,638,000 pounds. The total phosphate added was 1,740,200 pounds. Of this amount, 12,4 per cent of the nitrate and 18.0 per cent of the phosphate was released from the lake through the Jordan River. The rest remained in the lake to be recycled. Of the total nitrate and phosphate dumped into the lake, the municipal and industrial waste treatment plants contributed 28.7 per cent of the nitrate and 47.1 per cent of the phosphate. Groundwater contributed 15.4 per cent of the nitrate and 19.2 per cent of the phosphate. The tributaries contributed 55.8 per cent of the nitrate and 33.7 per cent of the phosphate. It is evident that the nutrient level of the lake is increasing rapidly from year to year, because more nutrients are going into the lake than are released through the Jordan River.

No description available.

No description available.

The increasing interest in adaptive models of governance and adaptive tools for management stems from a recognition that the traditional paradigm in natural resource management is failing to adequately maintain the resilience of social-ecological systems. A principal reason for this failure is that each problem is treated discretely by approaches that are characteristically narrow and reactive rather than comprehensive and forward-looking. This lack of sophistication means that traditional governance models are unsuitable for dealing with the inherent uncertainty characteristic of environmental problems, and for dealing with the conflicts that emanate from the social construction of those problems. The challenge presented by these uncertainties and conflicts illuminates deficiencies in how we conceptualize the dynamics of social-ecological systems and how we formulate approaches to policy and problem solving to cope effectively with those dynamics. What changes in governance could remedy these deficiencies with more effective forms of collective action that sustain and enhance social-ecological resilience? My purpose was to pursue those changes with an examination of the human dimension of governance, with specific reference to the Great Lakes and potential features of an adaptive paradigm for the Great Lakes Water Quality Agreement. The goals of this research were to contribute knowledge and perspective on our understanding of and progress towards adaptive Great Lakes governance, and secondly, to generate pragmatic and actionable policy options for enhancing participatory processes, social learning, and leadership for adaptive Great Lakes governance. To achieve these goals, I sought the following specific objectives: (1) identify aspects of the Agreement that would compel a more rigorous and evaluative approach to policy development and implementation in the Great Lakes; (2) acquire evidence to characterize deficits in the implementation of Great Lakes policy; (3) acquire evidence to characterize pathologies in the management of the Great Lakes; (4) (i) identify, detail, and combine the principles and processes of adaptive management and decision analysis, (ii) relate these mechanisms to policy and research in the Great Lakes context, especially where such mechanisms for managing in the face of uncertainty could ameliorate implementation deficits and management pathologies; and (5) (i) acquire evidence of the strengths and limitations in the development and implementation of Great Lakes Remedial Action Plans from people with direct experience with RAPs, (ii) identify and characterize potential reforms that could improve the design of community-based, nearshore restoration programs, and (iii) measure the desirability, feasibility, and likelihood for success of those reforms. Language in the Purpose of the Agreement, that the federal governments are to develop programs and practices for a better understanding of the Great Lakes, I interpret as inviting even demanding-the ongoing and rigorous pursuit of new knowledge and improved processes in Great Lakes governance to further place-based and regional restoration. Policy implementation deficits identified included a lack of understanding of cause and effect, inadequate communication and coordination, lack of time and resources for full implementation, and lack of agreement on objectives. Pathologies of management included a lack of responsiveness, a lack of institutional analysis and program evaluation, a resistance to new information and ideas, a lack of appropriate personalities in key roles, and multiple and incompatible programming. Policy tools for improved human-environment and science-policy linkages were examined as potential governance mechanisms to counter deficits and pathologies. Design principals of adaptive management and decision analysis were specified. These tools were placed within the policy and research context of the Great Lakes regime and linked to improved forms of accountability. A three-round online Policy Delphi study involved several dozen experts in the development and implementation of RAPs across the Great Lakes basin within government, industry, academia, and civil society. The research collected and aggregated (1) direct knowledge of the strengths and limitations of RAPs, which lead to (2) further knowledge of what worked and what did not work in the RAP program, which in turn facilitated (3) the emergence of seven governance options to improve institutional processes in RAP programming. Importantly, the results establish that both the structure and attributes of governance were significant to RAP outcomes. Ran kings of these options indicated a general consensus that the options were relatively feasible and likely to succeed as enhancements in the development and implementation of RAPs. The results indicate a need to focus significantly on the predominant tendencies and characteristic attitudes that underlie RAP processes. These findings will have broad significance for other evolving place-based nearshore restoration strategies in the Great Lakes and anywhere else such programs are initiated. The thesis culminates with a conceptual framework for adaptive governance, problem solving, decision making, and management. The framework encompasses three domains that correspond to established levels of institutional analysis: constitutional choice (political and societal processes), collective choice (policy and decision processes), and operational choice (resource use and management processes). Flows of information between domains can be facilitated or restricted depending on the rules and conventions of the institutional design. Traditional governance characteristically permits only a linear and downward flow of information that negates the possibility for double-loop learning by disallowing required feedbacks. Adaptive governance regimes intentionally encourage a return or upward (and outward) flow of information and promotes learning. The three domains in the framework are nested to indicate that the 'problem domain' is the entire social system, that problems of environmental governance cannot be restricted to subsets of issues, and that adaptive problem solving is multi-scalar. The framework explicitly links processes across domains and is adaptive because it bridges boundaries that traditionally separate society from policy decisions and isolate policy decisions from management activity. The Discussion underscores that learning is a key function of adaptive governance, and that it is operationalized through social capital, networks, leadership, and trust. The thesis recommends that the federal governments issue a reference to the International Joint Commission to establish an Adaptive Governance Task Force in order to provide a strong and independent forum to engage with the conceptual framework presented in this thesis and generally to discover adequate and appropriate strategies and opportunities for adaptive Great Lakes governance. / Thesis / Doctor of Philosophy (PhD)

Environmental quality and emissions guidelines are implemented due to their expected benefit for human and environmental health. However, implementation of such legislation requires knowledge of the behaviour and fate of the contaminants to be controlled. This thesis contributed to the overall understanding of atmospheric PAH deposition to remote lakes and the role atmospherically deposited contaminants play in site assessments which account for environmental pollution due to industry. In chapter 2, atmospheric PAH deposition derived from regional energy generation or industrial sources was found to be decreasing in recent sediments from Siskiwit Lake, Michigan, U.S.A. Considering that Siskiwit Lake is isolated from traffic and development, this supports recent theories which suggest that regional PAH deposition is being overprinting by local traffic sources in sub-urban or urban areas. This study also contributed to the understanding of perylene production in sediments by conclusively demonstrating increases in sedimentary perylene concentrations over a 20 year period. Moreover, kinetic modeling using 1st and 2nd order rate laws failed to accurately predict the concentration changes observed despite rate constants that were similar. This strongly suggested that perylene does not follow a simple concentration dependant kinetic reaction and is more likely controlled by complex kinetics perhaps involving biology. In chapter 3, the superiority of contaminant profiles in sediment cores over current dredge or grab sampling techniques was demonstrated. This was shown by successfully apportioning the source of contaminants to a northern lake as atmospheric deposition rather than point source release from the adjacent industrial facility. Contaminant profiles are able to constrain concentration changes with time and thus atmospheric deposition and point source contributions can be recognized. This is essential as chapter 3 also demonstrated that atmospheric deposition has the potential to produce sediment concentrations at or above current federal guidelines using standard dredge sampling techniques. Without the use of contaminant profiles these exceedences may be attributed incorrectly to industry which may face remediation costs or other fines associated with environmental contamination. This has implications for redefining sediment quality guidelines or currently accepted sampling methods. Moreover, remediation efforts for atmospherically deposited contaminants must differ from a point source release. Site remediation would be effective for a single release of contaminants however with a continuous source, as is the case with atmospheric deposition, remediation efforts must be focussed on the atmospheric contaminant emissions which can be a large distance from the site. / Thesis / Master of Science (MSc)