This dissertation outlines the contribution of evolutionary and environmental factors on North American freshwater fish morphological variation. A more thorough understanding of the factors which result in morphological variation is essential to describing patterns of evolutionary diversification, distribution, ecological niche, ontogeny, sexual dimorphism, ecosystem role, community assembly, invasion dynamics, and conservation. This dissertation makes a unique contribution to understanding morphological diversity in freshwater fishes by linking intraspecific and interspecific variation to phylogeny, allometry, sex, habitat niche, geographic niche, hydrology, and long term environmental change. This dissertation is comprised of three chapters which detail large scale macroevolutionary patterns in morphological variation for North American freshwater fishes, long term morphological changes with hydrological alterations in Cyprinidae, and phenotypic plasticity of freshwater drum in the Wabash River. Overall, North American fishes tend to be deeper bodied and more robust with larger body size, in females, in low flow and lentic hydrological conditions, and in taxa with smaller geographic range that occupy more specialized habitat niches. Further, macroevolutionary analysis suggests that the majority of morphological diversification occurred relatively early on in the evolutionary history of North American fishes. / Evolution of North American freshwater fish morphology with variation in habitat use and geographic range -- 100 years of hydrologic alterations and morphological variation in Cyprinidae -- Effects of allometry, sex and river location on morphological variation of freshwater drum Aplodinotus grunniens in the Wabash River, USA. / Department of Biology

<p>In the midwestern United States, nitrogen (N) pollution of surface and groundwaters is a substantial threat to water quality because of its ecological and human health effects. Hypoxia in the Gulf of Mexico is primarily caused by N runoff within the Mississippi River basin, and nitrate in drinking water may negatively impact human health in both adults and children. </p><p>Agricultural tile drainage is a common practice that facilitates the transport of N from fields to streams. While the impacts of tile drainage have been studied extensively at the field scale, the impacts on hydrology, nutrient transport, and groundwater recharge are still uncertain at the watershed and landscape scales. </p><p>The overall goal of this thesis work is to assess how tile drainage affects landscape-scale connectivity, hydrologic travel times, and N transport across a large catchment in west-central Indiana using 10 years of bi-annual water chemistry and stable isotope data from a community science education event. Land use data and a previously developed travel time distribution (TTD) model were also incorporated to accomplish this goal. A secondary goal is to estimate seasonal differences in groundwater recharge in west-central Indiana using stable water isotope data from precipitation and groundwater samples. </p><p>Qualitative travel times derived from δ²H and δ¹⁸O variability support the idea that short travel times have greater nitrate concentrations than long travel times. Greater N concentrations are also observed during wetter conditions with increased connectivity. The results of the GIS TTD model support the hypothesis that increasing drainage intensity reduces travel times. Groundwater recharge appears negligible in Tippecanoe County using a traditional water balance approach, but an isotope mass balance approach suggests that about 55-65% of annual recharge occurs during the summer and may be linked to intense precipitation events. </p><p>This knowledge improves our understanding of N transport and hydrologic connectivity in tile drained landscapes. The results of this thesis also demonstrate the importance of drainage density for travel times and provide additional insight into the seasonality of groundwater recharge in west-central Indiana. </p>

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Thesis (M.A.)--Miami University, Dept. of History, 2006. / Title from first page of PDF document. Includes bibliographical references (p. 57-62).

<p>In the context of climate change, increasing demands for freshwater make it necessary to manage our water resources in a sustainable way and find innovative ways to extend their life. An integrated water management approach needs to consider anthropogenic water use and reuse which represent major components of the current water cycle. In particular, unplanned, or de facto, indirect water reuse occurs in most of the U.S. river systems; however, there is little real-time documentation of it. Despite the fact that there are national and state agencies that systematically collect data on water withdrawals and wastewater discharges, their databases are organized and managed in a way that limits the ability to combine reported water data to perform large scale analysis about water use and indirect reuse. To better document these issues and to demonstrate the utility of such an analysis, I studied the Wabash River Watershed located in the U.S. Midwest. Existing data for freshwater extraction, use, discharge, and river streamflow were collected, curated and reorganized in order to characterize the water use and reuse within the basin. Indirect water reuse was estimated by comparing treated wastewater discharges with stream flows at selected points within the watershed. Results show that during the low flow months of July-October 2007, wastewater discharges into the Wabash River basin contributed 82 to 121% of the stream flow, demonstrating that the level of water use and unplanned reuse is significant. These results suggest that intentional water reuse for consumptive purposes such as landscape or agricultural irrigation could have substantial ecological impacts by diminishing stream flow during vulnerable low flow periods. This research also completed a time series watershed-scale analysis of water use and unplanned indirect reuse for the Wabash River Watershed from 2009 to 2017. Results document the occurrence of indirect water reuse over time, ranging from 3% to 134% in a water-rich area of the U.S. The time series analysis shows that reported data effectively describe the water use trends through nine years, clearly reflecting both anthropogenic and natural events in the watershed, such as the retirement of thermoelectric power plants, and the occurrence of an extreme drought in 2012. Results demonstrate the feasibility and significance of using available water datasets to perform large scale water use analysis, describe limitations encountered in the process, and highlight areas for improvement in water data management.</p>

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