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- Creators: Arizona State University
Hydrology and biogeochemistry are coupled in all systems. However, human decision-making regarding hydrology and biogeochemistry are often separate, even though decisions about hydrologic systems may have substantial impacts on biogeochemical patterns and processes. The overarching question of this dissertation was: How does hydrologic engineering interact with the effects of nutrient loading and climate to drive watershed nutrient yields? I conducted research in two study systems with contrasting spatial and temporal scales. Using a combination of data-mining and modeling approaches, I reconstructed nitrogen and phosphorus budgets for the northeastern US over the 20th century, including anthropogenic nutrient inputs and riverine fluxes, for ~200 watersheds at 5 year time intervals. Infrastructure systems, such as sewers, wastewater treatment plants, and reservoirs, strongly affected the spatial and temporal patterns of nutrient fluxes from northeastern watersheds. At a smaller scale, I investigated the effects of urban stormwater drainage infrastructure on water and nutrient delivery from urban watersheds in Phoenix, AZ. Using a combination of field monitoring and statistical modeling, I tested hypotheses about the importance of hydrologic and biogeochemical control of nutrient delivery. My research suggests that hydrology is the major driver of differences in nutrient fluxes from urban watersheds at the event scale, and that consideration of altered hydrologic networks is critical for understanding anthropogenic impacts on biogeochemical cycles. Overall, I found that human activities affect nutrient transport via multiple pathways. Anthropogenic nutrient additions increase the supply of nutrients available for transport, whereas hydrologic infrastructure controls the delivery of nutrients from watersheds. Incorporating the effects of hydrologic infrastructure is critical for understanding anthropogenic effects on biogeochemical fluxes across spatial and temporal scales.
In this study, I analyze the construction of childhood and nature in a number of Korean Theatre For Young Audience (TFY) works and family movies produced since 2000. Studying The Tale of Haruk, Gamoonjang Baby, Oseam and The Way Home, I explore the childhood memes that surface in the analysis and how they relate to dominant cultural understandings of Korean childhood. Both nature and childhood are metaphorical spaces reflecting the specificity of the cultural context in which they are situated. And in the works I explore, the two are paired in interesting and complex ways and for ideological reasons, the study of which produces a deeper understanding of the construction of Korean childhood. The “child" in Korean TFY has not been thoroughly explored in earlier scholarly work, nor do many preceding studies explore the performance texts of Korean TFY from an analytic stance. This is a serious gap in the literature, considering the significance of the discourse on childhood as a major conceptual framework bolstering TFY and the centrality of the performative aspect of the field. Thus, this study is meaningful as one of the first doctoral works to analyze the performance texts of Korean TFY and the first work to explore Korean TFY from a childhood studies framework. The findings of this interdisciplinary work will be of interest to the field of childhood studies and TFY, broadly defined. In studying the works, my main methodology has been detailed performance analysis. Through the analysis, interesting tropes of Korean childhood emerge, some of which have not been addressed explicitly before. My work reveals Korean childhood as a hybrid cultural assemblage reflecting the complexity of the Korean cultural context, where historical, current, native and foreign ideas about childhood mingle.
More than half of all accessible freshwater has been appropriated for human use, and a substantial portion of terrestrial ecosystems have been transformed by human action. These impacts are heaviest in urban ecosystems, where impervious surfaces increase runoff, water delivery and stormflows are managed heavily, and there are substantial anthropogenic sources of nitrogen (N). Urbanization also frequently results in creation of intentional novel ecosystems. These "designed" ecosystems are fashioned to fulfill particular needs of the residents, or ecosystem services. In the Phoenix, Arizona area, the augmentation and redistribution of water has resulted in numerous component ecosystems that are atypical for a desert environment. Because these systems combine N loading with the presence of water, they may be hot spots of biogeochemical activity. The research presented here illustrates the types of hydrological modifications typical of desert cities and documents the extent and distribution of common designed aquatic ecosystems in the Phoenix metropolitan area: artificial lakes and stormwater retention basins. While both ecosystems were designed for other purposes (recreation/aesthetics and flood abatement, respectively), they have the potential to provide the added ecosystem service of N removal via denitrification. However, denitrification in urban lakes is likely to be limited by the rate of diffusion of nitrate into the sediment. Retention basins export some nitrate to groundwater, but grassy basins have higher denitrification rates than xeriscaped ones, due to higher soil moisture and organic matter content. An economic valuation of environmental amenities demonstrates the importance of abundant vegetation, proximity to water, and lower summer temperatures throughout the region. These amenities all may be provided by designed, water-intensive ecosystems. Some ecosystems are specifically designed for multiple uses, but maximizing one ecosystem service often entails trade-offs with other services. Further investigation into the distribution, bundling, and tradeoffs among water-related ecosystem services shows that some types of services are constrained by the hydrogeomorphology of the area, while for others human engineering and the creation of designed ecosystems has enabled the delivery of hydrologic ecosystem services independent of natural constraints.