Thesis (Ph.D.) -- University of Montana, 2008. / Title from author supplied metadata. Description based on contents viewed on July 6, 2009. Includes bibliographical references.

Thesis (M.S.)--University of North Carolina Wilmington, 2009. / Title from PDF title page (February 22, 2010) Includes bibliographical references (p. 48-51)

Thesis (M.S.)--University of Nevada, Reno, 2008. / "December, 2008." Includes bibliographical references (leaves 32-35). Online version available on the World Wide Web.

The concentrations of various forms of nitrogen and phosphorus in the main stream and selected tributaries of Pirron Yallock Creek, southwestern Victoria were examined over a two-year period. Exceedingly high levels of both nutrients were found within a particular tributary, while generally high nutrient levels were observed throughout the catchment. The speciation results indicated that dairy effluent was the primary source of nutrients to Pirron Yallock Creek. A palaeolimnological study was undertaken to determine the impact of European settlement upon waterway nutrient concentrations within the region. The palaeolimnological study focused primarily on the diatom flora preserved within the sediments of nearby Lakes Corangamite and Bullen Merri. Lack of preservation of diatoms within the sediments of Lake Corangamite resulted in no water quality inferences for this lake. The preserved diatoms within Lake Bullen Merri suggested an increase in trophic status of this lake during the last 500 years. While a change in the diatom flora of Lake Bullen Merri was evident, it was not possible to differentiate the impact of European settlement upon nutrient status of this waterway from long-term trophic status change. In light of the particularly high nutrient concentrations observed in Pirron Yallock Creek, improved nutrient management strategies are proposed for the catchment. These strategies, which consider current nutrient management activities, are predominantly focussed on the dairy industry, which occupies the majority of the catchment.

Three watersheds of Upper White River were chosen for this study. Stream samples were tested for total suspended solids and conductivity. Fourteen percent of the total suspended solids samples were above 80 mg L-1 which can cause negative effects to aquatic life. Total suspended solids results were tested with a general linear model and in linear regressions with discharge and nutrients. Conductivity results were tested with a general linear model. Concentrations of the total suspended solids were significantly related to watershed, Julian date, the interaction of watershed and Julian date, and discharge. Increasing total suspended solids concentrations were significantly related to increasing concentrations of orthophosphate, nitrate, and ammonia. Conductivity levels were significantly related to watershed, location within watershed, and Julian date. Total suspended solids, discharge, and nutrient concentrations were high in the spring, but decreased in the following seasons. / Department of Natural Resources and Environmental Management

Thesis (M.S.)--University of North Carolina at Wilmington, 2005. / Includes bibliographical references (leaves: 48-49)

Thesis (M.S.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 69-74). Also available on the World Wide Web.

Nutrient limitation in aquatic ecosystems results from a deficiency in nitrogen or phosphorus levels relative to cellular growth needs. Nutrient limitation of freshwater systems is a function of biotic and abiotic factors. Biotic factors include vascular and nonvascular plant community composition. Abiotic factors include underlying bedrock and land-use activities (e.g. agriculture, septic systems). Nutrient availability directly affects growth, productivity, and community structure of primary producers. The purpose of this study was two-fold: (1) to assess the relationship between ambient algal biomass. and in-stream nutrient levels along the longitudinal course of a river through a transition from weak to well-developed underlying karst bedrock, and (2) experimentally assess if periphyton was nitrogen or phosphorous limited between weak and well-developed karst sites. Sestonic and filamentous biomass (= chlorophyll-a) levels increased monthly along the longitudinal gradient. In contrast, periphyton biomass levels increased minimally monthly and displayed no longitudinal pattern. Nitrate and soluble reactive phosphorus levels exhibited distinct longitudinal increases, whereas total phosphorous displayed minimal change and ammonia levels decreased in the downstream direction. Total nitrogen (TN) levels increased upstream but decreased sharply in the well-developed downstream karst sites. The nutrient limitation assays revealed that the highest periphyton levels were with N + P treatments at the most upstream sites. Overall, in Kentucky's Green River algal biomass accrual appears to be mainly P-limited but likely also by TN availability during late summer.

Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / Department of Natural Resources and Environmental Management

In North America, the acceleration of the eutrophication of surface waters due to nutrient pollution is still present. Soil studies have not entirely succeeded in linking nutrient and sediment losses to field hydrology because relationships between discharge and dissolved ions/sediments are complicated by a hysteresis effect which has been only described qualitatively. The objective of this thesis was to better understand the effects of hydrology on N, P, and sediment transfer from agricultural and forest soils to surface waters. This was done by developing a technique, called the H index, to quantify the hysteretic behaviour of ion and sediment transport in stream/overland water. The chemical and sediment concentrations in a stream of a forested watershed in the Sierra Nevada during snowmelt and in overland runoff of two agricultural fields during rain events in the Montreal area were examined. In the stream of the forested watershed, H indices for suspended sediment increased (looser hysteresis loop) with the availability of sediments and the lag between peaks in suspended sediment concentrations and discharge. In agricultural fields, nutrient concentrations increased with time during each event with presence of counterclockwise and clockwise hysteresis. The hysteretic behaviour of suspended sediments was not significantly related with either prior soil moisture content or rainfall characteristics. In order to simultaneously monitor P and N in the stream and soils of the forested watershed, a laboratory study was conducted to investigate the efficacy of various mixedbed exchange resins in absorbing dissolved organic and inorganic N and P. Results showed that mixed-bed resin was adequate for characterizing P on a short-time scale but longer exposure periods were required for N. Results from the resin exchange reveal the possibility that the spring time pulse of NOs'-N in stream water was due to the melting of the snowpack.