Elevated groundwater nitrate (NO3
-) concentrations in the Southern Willamette
Valley (SWV) caused the Oregon Department of Environmental Quality (ODEQ) to
declare a Groundwater Management Area (GWMA) in Spring, 2004. To better
understand direction of groundwater flow, groundwater age, and nitrate transport
pathways of the SWV we developed a steady-state...
Seeding is a vital tool to facilitate recovery of degraded ecosystems, but low seedling recruitment rates limit the utility of this practice in a range of ecosystems across the globe. Plant functional traits impact individual fitness through effects on growth, reproduction and survival. Consequently, seed and seedling trait variation among...
Marine environments provide services for ecosystems and humans, but face many threats, including sea star wasting disease (SSWD) and ocean acidification (OA). Biological research on these threats is abundant, but there has been limited research examining the human dimensions of these threats. This thesis contains two standalone articles that explore...
Predicting the average affect of a piece of music is a task which has been of recent interest in the field of music information retrieval. We investigate the use of sentiment analysis on online social media conversations to predict a song’s valence and arousal. Using four music emotion datasets -...
Few studies have directly compared denitrifying community composition and activities in soils by coupling molecular-genetic techniques and traditional measures of denitnfication. I investigated communities of denitrifying bacteria from adjacent meadow and forest soils in the Cascade Mountains, Oregon. A key gene in the denitrification pathway, N₂O reductase (nosZ), served as...
Understanding the processes involved in the transport of dissolved gas plumes in groundwater aquifers is essential for comprehending the effect that these transport processes can have on site characterization and remedial design applications. Previous laboratory and field studies have indicated that dissolved gas transport in groundwater can be greatly affected...
A number of steelhead (Oncorhynchus mykiss) populations are at risk throughout Oregon, including five populations that are federally listed as threatened or endangered. However, little is known about behavior and survival of these fish as they transition from freshwater to seawater. We investigated whether estuarine survival varies on a temporal...
This dissertation presents the results of statistical analyses of large climate datasets from two time intervals – the 20th century instrumental record and the proxy record of the last deglaciation – in order to understand the forcings and mechanisms of past climate variability.
A longstanding question in climate dynamics concerns...
Queer students in American public schools may face significant challenges including unsupportive or hostile peers or staff members (Eisenberg et al., 2017). The culture of rural Southern schools may be particularly challenging for these students as they are less likely to have an active support group and more likely to...
Biological plant invasions are diminishing the ecological integrity and function of ecosystems worldwide. A primary example of this is in the Great Basin of the United States, where invasive annual grasses, like cheatgrass (Bromus tectorum L.) and medusahead (Taeniatherum caput-medusae L. Nevski), are dominating many sagebrush-steppe ecosystems. In these invaded...