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• 1. [Article] Carbon and Oxygen Isotope Fractionation in Laboratory-Precipitated, Inorganic Calcite

  Carbon and oxygen isotopes in calcite crystals provide a record of the environmental conditions under which the crystals formed. To investigate the influence of temperature, pH, and growth rate on isotope ...

  Citation × Citation Citation Abstract Copy Title: Carbon and Oxygen Isotope Fractionation in Laboratory-Precipitated, Inorganic Calcite Author: Baker, Evan Year: 2015 Carbon and oxygen isotopes in calcite crystals provide a record of the environmental conditions under which the crystals formed. To investigate the influence of temperature, pH, and growth rate on isotope discrimination by calcite, we measured carbon and oxygen isotope fractionation through a series of calcite precipitation experiments at T = 25C and pH = 7.5 - 9.3. We observe that neither the carbon nor oxygen isotope compositions correspond to the theoretical equilibrium isotope fractionation between calcite and solution. We also demonstrate that the fractionation of oxygen isotopes between calcite and water decreases with increasing pH, consistent with available data from experiments in which the enzyme carbonic anhydrase was used. Finally, we compare the carbon and oxygen isotopes of our calcite crystals to those of biogenic carbonates. This thesis includes previously unpublished co-authored material. Title: Carbon and Oxygen Isotope Fractionation in Laboratory-Precipitated, Inorganic Calcite Author: Baker, Evan Year: 2015 Carbon and oxygen isotopes in calcite crystals provide a record of the environmental conditions under which the crystals formed. To investigate the influence of temperature, pH, and growth rate on isotope discrimination by calcite, we measured carbon and oxygen isotope fractionation through a series of calcite precipitation experiments at T = 25C and pH = 7.5 - 9.3. We observe that neither the carbon nor oxygen isotope compositions correspond to the theoretical equilibrium isotope fractionation between calcite and solution. We also demonstrate that the fractionation of oxygen isotopes between calcite and water decreases with increasing pH, consistent with available data from experiments in which the enzyme carbonic anhydrase was used. Finally, we compare the carbon and oxygen isotopes of our calcite crystals to those of biogenic carbonates. This thesis includes previously unpublished co-authored material. Close

• 2. [Article] Climate Change Impacts on the Productivity and Community Dynamics of Pacific Northwest Prairie Systems

  1 page poster

  Citation × Citation Citation Abstract Copy Title: Climate Change Impacts on the Productivity and Community Dynamics of Pacific Northwest Prairie Systems Author: Okotie-Oyekan, Aimee Year: 2017 1 page poster Title: Climate Change Impacts on the Productivity and Community Dynamics of Pacific Northwest Prairie Systems Author: Okotie-Oyekan, Aimee Year: 2017 1 page poster Close

• 3. [Article] Mapping Virtual Water Use in Canada’s Prairies: A Comparison between Prairie Virtual Water Demands and Renewable Supply

  66 pages. A thesis presented to the Department of Geography and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring ...

  Citation × Citation Citation Abstract Copy Title: Mapping Virtual Water Use in Canada’s Prairies: A Comparison between Prairie Virtual Water Demands and Renewable Supply Author: Garcia, Gregory "Manny" Manuel Year: 2014 66 pages. A thesis presented to the Department of Geography and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2014. Title: Mapping Virtual Water Use in Canada’s Prairies: A Comparison between Prairie Virtual Water Demands and Renewable Supply Author: Garcia, Gregory "Manny" Manuel Year: 2014 66 pages. A thesis presented to the Department of Geography and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2014. Close

• 4. [Article] Microbial Biodiversity of the Atmosphere

  Microorganisms are critical to the functioning of terrestrial and aquatic ecosystems and may also play a role in the functioning of the atmosphere. However, little is known about the diversity and function ...

  Citation × Citation Citation Abstract Copy Title: Microbial Biodiversity of the Atmosphere Author: Klein, Ann Year: 2016 Microorganisms are critical to the functioning of terrestrial and aquatic ecosystems and may also play a role in the functioning of the atmosphere. However, little is known about the diversity and function of microorganisms in the atmosphere. To investigate the forces driving the assembly of bacterial microbial communities in the atmosphere, I measured temporal variation in bacterial diversity and composition over diurnal and inter-day time scales. Results suggest that bacterial communities in the atmosphere markedly vary over diurnal time scales and are likely structured by inputs from both local terrestrial and long-distance sources. To assess the potential functions of bacteria and fungi in the atmosphere, I characterized total and potentially active communities using both RNA- and DNA-based data. Results suggest there are metabolically active microorganisms in the atmosphere that may affect atmospheric functions including precipitation development and carbon cycling. This dissertation includes previously published and unpublished co-authored material. Title: Microbial Biodiversity of the Atmosphere Author: Klein, Ann Year: 2016 Microorganisms are critical to the functioning of terrestrial and aquatic ecosystems and may also play a role in the functioning of the atmosphere. However, little is known about the diversity and function of microorganisms in the atmosphere. To investigate the forces driving the assembly of bacterial microbial communities in the atmosphere, I measured temporal variation in bacterial diversity and composition over diurnal and inter-day time scales. Results suggest that bacterial communities in the atmosphere markedly vary over diurnal time scales and are likely structured by inputs from both local terrestrial and long-distance sources. To assess the potential functions of bacteria and fungi in the atmosphere, I characterized total and potentially active communities using both RNA- and DNA-based data. Results suggest there are metabolically active microorganisms in the atmosphere that may affect atmospheric functions including precipitation development and carbon cycling. This dissertation includes previously published and unpublished co-authored material. Close

• 5. [Article] A Biogeochemical Study of Groundwater Arsenic Contamination in the Southern Willamette Basin, Oregon, USA

  The mobilization and transformation of arsenic within the critical zone is a major cause of human suffering worldwide. Microorganisms, as they grow and utilize organic matter, accelerate redox processes ...

  Citation × Citation Citation Abstract Copy Title: A Biogeochemical Study of Groundwater Arsenic Contamination in the Southern Willamette Basin, Oregon, USA Author: Maguffin, Scott Year: 2016 The mobilization and transformation of arsenic within the critical zone is a major cause of human suffering worldwide. Microorganisms, as they grow and utilize organic matter, accelerate redox processes that can transform and mobilize arsenic within aquifers on a large scale. As such, naturally occurring groundwater arsenic is a particularly hazardous problem that is chronically poisoning over 100 million people annually. Historically, groundwater arsenic research has been focused on the two principal inorganic arsenic species: arsenate [As(V)] and arsenite [As(III)]. Recently, organic arsenic species have garnered more attention due to their mobility, toxicity, and contemporary recognition of the ephemeral yet significant role they have in the global arsenic cycle. Here, I discuss laboratory and in situ experiments focused on exploring how microorganisms transform, mobilize, and sequester arsenic within a biogeochemically complex aquifer system. In my laboratory experiments, I collected aquifer sediments from a naturally contaminated bedrock aquifer and incubated a series of laboratory microcosms. Our results show that simultaneously robust iron and sulfate reduction temporarily mitigated arsenic contamination but then directed arsenic to an unstable adsorbed phase were it was later mobilized. Second, I discuss two aquifer injection experiments designed to examine in situ microbial redox processes and the further explore the potential to stimulate arsenic sequestration through arsenic-sulfide precipitation. Our results show that in situ stimulation of microbial metabolisms accelerated the reduction of arsenic bearing iron (oxy)hydroxides as well as sulfate and arsenic reduction. Within 3 weeks of these contemporaneously occurring redox reactions, 90% of the dissolved inorganic arsenic was removed (~2000 ppb) and an effective long-term, anaerobically stable, sequestration of arsenic was observed by way of a significant increase of arsenic-sulfide precipitate. Finally, using both the laboratory and field experiments, I explore the potential of organic arsenic production rates under stimulated conditions. We report new methylation rates that are consequential to the potential efficacy of enhanced, biologically-driven arsenic remediation and the reconsidered significance of biomethylation pathways in aquifers. These results expand our current understanding of the metabolic reach aquifer microorganisms potentially have over the fate of arsenic. Title: A Biogeochemical Study of Groundwater Arsenic Contamination in the Southern Willamette Basin, Oregon, USA Author: Maguffin, Scott Year: 2016 The mobilization and transformation of arsenic within the critical zone is a major cause of human suffering worldwide. Microorganisms, as they grow and utilize organic matter, accelerate redox processes that can transform and mobilize arsenic within aquifers on a large scale. As such, naturally occurring groundwater arsenic is a particularly hazardous problem that is chronically poisoning over 100 million people annually. Historically, groundwater arsenic research has been focused on the two principal inorganic arsenic species: arsenate [As(V)] and arsenite [As(III)]. Recently, organic arsenic species have garnered more attention due to their mobility, toxicity, and contemporary recognition of the ephemeral yet significant role they have in the global arsenic cycle. Here, I discuss laboratory and in situ experiments focused on exploring how microorganisms transform, mobilize, and sequester arsenic within a biogeochemically complex aquifer system. In my laboratory experiments, I collected aquifer sediments from a naturally contaminated bedrock aquifer and incubated a series of laboratory microcosms. Our results show that simultaneously robust iron and sulfate reduction temporarily mitigated arsenic contamination but then directed arsenic to an unstable adsorbed phase were it was later mobilized. Second, I discuss two aquifer injection experiments designed to examine in situ microbial redox processes and the further explore the potential to stimulate arsenic sequestration through arsenic-sulfide precipitation. Our results show that in situ stimulation of microbial metabolisms accelerated the reduction of arsenic bearing iron (oxy)hydroxides as well as sulfate and arsenic reduction. Within 3 weeks of these contemporaneously occurring redox reactions, 90% of the dissolved inorganic arsenic was removed (~2000 ppb) and an effective long-term, anaerobically stable, sequestration of arsenic was observed by way of a significant increase of arsenic-sulfide precipitate. Finally, using both the laboratory and field experiments, I explore the potential of organic arsenic production rates under stimulated conditions. We report new methylation rates that are consequential to the potential efficacy of enhanced, biologically-driven arsenic remediation and the reconsidered significance of biomethylation pathways in aquifers. These results expand our current understanding of the metabolic reach aquifer microorganisms potentially have over the fate of arsenic. Close

• 6. [Article] Wavelet Analysis of Northeastern United States Climate Data

  59 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Summer 2...

  Citation × Citation Citation Abstract Copy Title: Wavelet Analysis of Northeastern United States Climate Data Author: Womack, Michael Thomas Year: 2017 59 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Summer 2017 Title: Wavelet Analysis of Northeastern United States Climate Data Author: Womack, Michael Thomas Year: 2017 59 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Summer 2017 Close

• 7. [Article] From the Fields to the Streets to the Stage: Chicana Agency and Identity Within the Movimiento

  The unionization of the United Farm Workers in 1962 precipitated the longest labor movement in US history, which in turn inspired all sectors of Chicana/o activism and artistic production. As the Movimiento ...

  Citation × Citation Citation Abstract Copy Title: From the Fields to the Streets to the Stage: Chicana Agency and Identity Within the Movimiento Author: Moberg, Erin Year: 2016 The unionization of the United Farm Workers in 1962 precipitated the longest labor movement in US history, which in turn inspired all sectors of Chicana/o activism and artistic production. As the Movimiento gained support and recognition throughout the 1960s, grassroots and activist theater and performance played fundamental roles in representing its causes and goals. By the 1980s, however, the Movimiento was frequently represented and understood as a reclaiming of Chicano identity through an assertion of Chicano masculinity, a reality which rendered the participation and cultural production of Chicanas even less visible within an already marginalized cultural and historical legacy. In this dissertation, I seek to develop historically grounded answers to questions around issues of male visibility and female and lesbian/gay/bisexual/queer invisibility within the Movimiento and dominant Anglo culture. I work to bridge this critical gap in the treatment of plays by Chicana/o dramatists in two ways: (1) by examining plays by Chicanas without attributing or reducing their impact to their identities as women, lesbians, and/or feminists but rather by considering the performative characteristics of their works and (2) by engaging issues of gender and sexual biases and hierarchies across several decades of Chicana/o cultural production. A primary goal of this project is to shift and expand the critical focus of scholarship and discourse on Chicana/o theater and performance in order to consider the lived experiences and creative contributions of the many participants in the Movimiento, many of whom are not represented through the perspective, experience, and voice of the heteropatriarchal Chicano subject. I maintain that we must take into account multiple and often conflicting representations of the Movimiento and of Chicana/o identity in order to more fully understand the history of Chicana/os in the US and to better confront the mechanisms of exclusion toward Chicana/os that have continued into our present moment. At stake is the equal treatment and inclusion of the contributions of Chicana and lesbian/gay/bisexual/queer Chicana/o dramatists as well as a more profound and nuanced understanding of the fight for the liberation of multiple and diverse Chicana/o subjects that has continued into our present moment. Title: From the Fields to the Streets to the Stage: Chicana Agency and Identity Within the Movimiento Author: Moberg, Erin Year: 2016 The unionization of the United Farm Workers in 1962 precipitated the longest labor movement in US history, which in turn inspired all sectors of Chicana/o activism and artistic production. As the Movimiento gained support and recognition throughout the 1960s, grassroots and activist theater and performance played fundamental roles in representing its causes and goals. By the 1980s, however, the Movimiento was frequently represented and understood as a reclaiming of Chicano identity through an assertion of Chicano masculinity, a reality which rendered the participation and cultural production of Chicanas even less visible within an already marginalized cultural and historical legacy. In this dissertation, I seek to develop historically grounded answers to questions around issues of male visibility and female and lesbian/gay/bisexual/queer invisibility within the Movimiento and dominant Anglo culture. I work to bridge this critical gap in the treatment of plays by Chicana/o dramatists in two ways: (1) by examining plays by Chicanas without attributing or reducing their impact to their identities as women, lesbians, and/or feminists but rather by considering the performative characteristics of their works and (2) by engaging issues of gender and sexual biases and hierarchies across several decades of Chicana/o cultural production. A primary goal of this project is to shift and expand the critical focus of scholarship and discourse on Chicana/o theater and performance in order to consider the lived experiences and creative contributions of the many participants in the Movimiento, many of whom are not represented through the perspective, experience, and voice of the heteropatriarchal Chicano subject. I maintain that we must take into account multiple and often conflicting representations of the Movimiento and of Chicana/o identity in order to more fully understand the history of Chicana/os in the US and to better confront the mechanisms of exclusion toward Chicana/os that have continued into our present moment. At stake is the equal treatment and inclusion of the contributions of Chicana and lesbian/gay/bisexual/queer Chicana/o dramatists as well as a more profound and nuanced understanding of the fight for the liberation of multiple and diverse Chicana/o subjects that has continued into our present moment. 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• 8. [Article] Climate Change and Peruvian Potato Farming: Traditional Knowledge in Climate Change Adaptation

  58 pages. A thesis presented to the Department of Environmental Studies and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Arts, ...

  Citation × Citation Citation Abstract Copy Title: Climate Change and Peruvian Potato Farming: Traditional Knowledge in Climate Change Adaptation Author: Giamberso, Lisa Rose Year: 2014 58 pages. A thesis presented to the Department of Environmental Studies and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Arts, Spring 2014. Title: Climate Change and Peruvian Potato Farming: Traditional Knowledge in Climate Change Adaptation Author: Giamberso, Lisa Rose Year: 2014 58 pages. A thesis presented to the Department of Environmental Studies and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Arts, Spring 2014. Close

• 9. [Article] Essays on Economic Development and Climate Change

  The first essay considers the relative effectiveness of government and non-governmental organizations (NGOs) as channels to allocate resources. I use a catastrophic climate-related shock--Hurricane Mitch--to ...

  Citation × Citation Citation Abstract Copy Title: Essays on Economic Development and Climate Change Author: Fitch-Fleischmann, Benjamin Year: 2015 The first essay considers the relative effectiveness of government and non-governmental organizations (NGOs) as channels to allocate resources. I use a catastrophic climate-related shock--Hurricane Mitch--to examine the political economy of these channels of aid distribution at the micro level. I combine extensive data on aid received by Nicaraguan households with data on municipal election outcomes and an exogenous, precipitation-based measure of hurricane impact. I find that the hurricane had long-lasting effects on the aid received by households from both NGOs and the government. In the short term, however, the government did not provide aid according to the objective measure of hurricane damage but instead provided aid along political lines. The second essay presents estimates of a relationship between extreme hot temperatures during gestation and a child's subsequent physical well-being in a sample of children in Peru, thus extending existing evidence constructed from U.S. data. Estimates are constructed using high-resolution gridded climate data and geo-coded household surveys. The results suggest that a period of extreme heat (a month whose average temperature is more than 2 standard deviations above the local average) in the period 1 to 3 months before birth is associated with lower weight at birth and a reduction in height (measured 1 to 59 months after birth) that cannot be fully explained by birth weight. There is no evidence of differential maternal investment, as measured by duration of breastfeeding, according to a child's exposure to extreme heat during gestation. The third essay asks whether improved treatment of HIV/AIDS in Africa can be achieved simply by paying health workers to do more. I present estimates of the impact of financial incentives paid to individual workers at public health facilities in Mozambique. The results suggest that piece-rate incentives increased the delivery of five out of fourteen health services for which treatment effects can be identified, with estimated increases ranging from 34 to 157 percent, depending on the particular service. I find no evidence of a corresponding decrease in the delivery of services that are not financially incentivized, suggesting that there is no "crowding out" of intrinsic motivation. Title: Essays on Economic Development and Climate Change Author: Fitch-Fleischmann, Benjamin Year: 2015 The first essay considers the relative effectiveness of government and non-governmental organizations (NGOs) as channels to allocate resources. I use a catastrophic climate-related shock--Hurricane Mitch--to examine the political economy of these channels of aid distribution at the micro level. I combine extensive data on aid received by Nicaraguan households with data on municipal election outcomes and an exogenous, precipitation-based measure of hurricane impact. I find that the hurricane had long-lasting effects on the aid received by households from both NGOs and the government. In the short term, however, the government did not provide aid according to the objective measure of hurricane damage but instead provided aid along political lines. The second essay presents estimates of a relationship between extreme hot temperatures during gestation and a child's subsequent physical well-being in a sample of children in Peru, thus extending existing evidence constructed from U.S. data. Estimates are constructed using high-resolution gridded climate data and geo-coded household surveys. The results suggest that a period of extreme heat (a month whose average temperature is more than 2 standard deviations above the local average) in the period 1 to 3 months before birth is associated with lower weight at birth and a reduction in height (measured 1 to 59 months after birth) that cannot be fully explained by birth weight. There is no evidence of differential maternal investment, as measured by duration of breastfeeding, according to a child's exposure to extreme heat during gestation. The third essay asks whether improved treatment of HIV/AIDS in Africa can be achieved simply by paying health workers to do more. I present estimates of the impact of financial incentives paid to individual workers at public health facilities in Mozambique. The results suggest that piece-rate incentives increased the delivery of five out of fourteen health services for which treatment effects can be identified, with estimated increases ranging from 34 to 157 percent, depending on the particular service. I find no evidence of a corresponding decrease in the delivery of services that are not financially incentivized, suggesting that there is no "crowding out" of intrinsic motivation. Close

• 10. [Article] Controls on the Kinematics of Slow-moving Landslides from Satellite Radar Interferometry and Mechanical Modeling

  Landslides display a wide variety of behaviors ranging from slow persistent motion to rapid acceleration and catastrophic failure. Given the variety of possible behaviors, improvements to our understanding ...

  Citation × Citation Citation Abstract Copy Title: Controls on the Kinematics of Slow-moving Landslides from Satellite Radar Interferometry and Mechanical Modeling Author: Handwerger, Alexander Year: 2015 Landslides display a wide variety of behaviors ranging from slow persistent motion to rapid acceleration and catastrophic failure. Given the variety of possible behaviors, improvements to our understanding of landslide mechanics are critical for accurate predictions of landslide dynamics. Recent advances in remote sensing techniques, like satellite radar interferometry (InSAR), now enable high-resolution spatial and temporal measurements that provide insight into the mechanisms that control landslide behavior. In this dissertation, I use InSAR and high-resolution topographic data to identify 50 slow-moving landslides in the Northern California Coast Ranges and monitor their kinematics over 4 years. These landslides have similar mechanical properties and are subject to the same external forcings, which allows me to explore geometrical controls on kinematics. Each landslide displays distinct kinematic zones with different mean velocities that remain spatially fixed. Because these deformation patterns are sensitive to subsurface geometry, I employ a mathematical model to infer landslide thickness and find that these landslides exhibit a highly variable thickness and an irregular basal sliding surface. Time series analysis reveals that each landslide displays well-defined seasonal velocity changes with a periodicity of ∼ 1 year. These velocity variations are driven by precipitation- induced changes in pore-water pressure that lag the onset of rainfall by up to 40 days. Despite significant variations in geometry, I find no systematic differences in seasonal landslide behavior. To further explore how stress perturbations control landslide motion, I develop a mechanical model that reproduces both the displacement patterns observed at slow-moving landslides and the acceleration towards failure exhibited by catastrophic events. I find that catastrophic failure can only occur when the slip surface is characterized by rate-weakening friction and its spatial dimensions exceed a critical nucleation length that is shorter for higher effective stresses. These model simulations support my conclusions from the remote sensing analysis but also provide insight into the long-term evolution of landslides. This dissertation includes both previously published and unpublished co- authored material. Title: Controls on the Kinematics of Slow-moving Landslides from Satellite Radar Interferometry and Mechanical Modeling Author: Handwerger, Alexander Year: 2015 Landslides display a wide variety of behaviors ranging from slow persistent motion to rapid acceleration and catastrophic failure. Given the variety of possible behaviors, improvements to our understanding of landslide mechanics are critical for accurate predictions of landslide dynamics. Recent advances in remote sensing techniques, like satellite radar interferometry (InSAR), now enable high-resolution spatial and temporal measurements that provide insight into the mechanisms that control landslide behavior. In this dissertation, I use InSAR and high-resolution topographic data to identify 50 slow-moving landslides in the Northern California Coast Ranges and monitor their kinematics over 4 years. These landslides have similar mechanical properties and are subject to the same external forcings, which allows me to explore geometrical controls on kinematics. Each landslide displays distinct kinematic zones with different mean velocities that remain spatially fixed. Because these deformation patterns are sensitive to subsurface geometry, I employ a mathematical model to infer landslide thickness and find that these landslides exhibit a highly variable thickness and an irregular basal sliding surface. Time series analysis reveals that each landslide displays well-defined seasonal velocity changes with a periodicity of ∼ 1 year. These velocity variations are driven by precipitation- induced changes in pore-water pressure that lag the onset of rainfall by up to 40 days. Despite significant variations in geometry, I find no systematic differences in seasonal landslide behavior. To further explore how stress perturbations control landslide motion, I develop a mechanical model that reproduces both the displacement patterns observed at slow-moving landslides and the acceleration towards failure exhibited by catastrophic events. I find that catastrophic failure can only occur when the slip surface is characterized by rate-weakening friction and its spatial dimensions exceed a critical nucleation length that is shorter for higher effective stresses. These model simulations support my conclusions from the remote sensing analysis but also provide insight into the long-term evolution of landslides. This dissertation includes both previously published and unpublished co- authored material. Close