Fresh Water Studies Commons^™

Improved Estimates Of Tributary Nitrogen Load To Casco Bay, Maine, Whitley J. Gray

Electronic Theses and Dissertations

Over the past two decades, total nitrogen (TN) concentrations have increased in Casco Bay (CBEP 2015). The sources of the increased nitrogen are poorly understood but occur with simultaneous population growth and land use changes. The total riverine nitrogen load to Casco Bay was previously estimated by Liebman and Milstead (2012) using the United States Geologic Survey’s (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model. The SPARROW model uses watershed characteristics, regional monitoring data and nitrogen source data to estimate nitrogen loading but was not validated using measurements of nitrogen in the Casco Bay watershed. This study attempts to …

Evaluating Potential For Water Quality Decline In Maine Lakes, Kaci N. Fitzgibbon

Electronic Theses and Dissertations

Understanding lake vulnerability with respect to eutrophication and loss of water quality is important for sustainability of aquatic ecosystems. This project aims at identifying and quantifying the effects of relevant physiochemical, climate, and watershed characteristics on lake vulnerability in order to develop management decision tools for the Maine Department of Environmental Protection (MEDEP). In a changing chemical and physical environment, using independent variables from each of these categories and then relating them to the summer lake epilimnetic phosphorus (P) concentrations allows for development of models to inform stakeholders of lake vulnerability to eutrophication problems.

We studied 24 lakes covering a …

A Paleolimnological Assessment Of Three Oligotrophic Watersheds In Maine, Tiffany Ann Wilson

Electronic Theses and Dissertations

Phosphorus (P) is a limiting nutrient in aquatic ecosystems. Its bioavailability determines the trophic status of lakes. The biogeochemistry of P in surface waters can be controlled by a combination of abiotic and biotic factors. Dissolved inorganic aluminum (Al) and iron (Fe) hydrolyze in streams and lakes to produce Al(OH)₃ and Fe(OH)₃ in the water column. These hydroxides may also form through photo-oxidation of complexes with DOC, liberation of inorganic metal species, and precipitation, followed by sedimentation. These solid phases readily adsorb P from the water column, reducing the amount that is available for biological nutrition (Kopácek et …

A Comparison Of The Ecological Integrity Of Headwater Streams Draining Harvested And Un-Harvested Watersheds In The Western Mountains Of Maine, U.S.A., Darlene Siegel

Electronic Theses and Dissertations

Physical, chemical, and biological characteristics of four headwater streams draining forested watersheds were compared to determine the effectiveness of Riparian Management Zones (RMZs) in protecting aquatic ecological integrity from the effects of forest harvesting. Two of the watersheds were harvested with a 30% sheltenvood cut and a 75 foot buffer was left adjacent to the streams. The other two watersheds were un-harvested and were used as reference conditions for comparison with the harvested watersheds. General environmental conditions in these four headwater streams during the study period were characterized as follows. Each stream was located within a mixed- wood forest dominated …

Effects Of Roadway-Related Physical And Chemical Habitat Alterations On Stream Ecosystems, Thomas Stuart Woodcock

Electronic Theses and Dissertations

Roadways are an important feature of both rural and urban landscapes, and disturbances associated with them have a variety of effects on stream ecosystems. Organisms may be differentially affected by toxic substances, depending on such factors as sediment and water chemistry, toxin bioavailability, uptake and elimination processes, and tolerance mechanisms. The effects of heavy metal pollution and habitat alteration related to urbanization and industry were examined along a gradient of impact in Goosefare Brook, a small stream in southern Maine with a history of water quality impahlent. The structure of invertebrate assemblages changed significantly along the gradient, and were related …

Arsenic In Drinking Water And Public Opinion On Wildlife Management As Case Studies Illustrating Natural Resource Policy, Jessica Sargent-Michaud

Electronic Theses and Dissertations

There are various ways to approach policy planning. This thesis consists of two Maine natural resource issue case studies illustrating different approaches to policy analysis. The first, a case study of arsenic contamination, is an example of a study that assembles information and provides that information to the public to influence public behavior. The second, a case study of wildlife management, is an example of a study that surveys the public to collect information on the public's opinions and attitudes to influence agency behavior towards the public. Arsenic in drinking water in Maine is a public health concern. There may …

Measures Of Denitrification In Selected South Dakota Semi-Permanent Prairie Pothole Wetlands, Beverly S. Klein

Electronic Theses and Dissertations

Wetlands are an integral part of agricultural systems in the prairie pothole regions of the North Central United States and Canadian Provinces. Little research has been done on denitrification in prairie potholes, and a better understanding of their denitrifying capability could aide in optimizing management practices near pothole areas. Most probable number (MPN) and denitrifying enzyme activity (DEA or Phase I) assays were conducted. Most probable number (MPN) measures were used to give an estimate of dissimilatory nitrate reduction to ammonia (DNRA) and denitrifying populations present in the wetlands. This study involved 3 selected semi-permanent prairie pothole wetlands near Madison, …