Physical Sciences and Mathematics Commons^™

Ecological Exposure And Effects Of Microplastics In Crabs Along The Pacific Coast, Dorothy A. Horn

Dissertations and Theses

Microplastics have been documented across the global oceans as an ubiquitous pollutant. Found in the water column, sediment, shorelines, estuaries, freshwater streams and rivers along with terrestrial soils, flora and fauna. The continuous input of plastic waste into the marine environment doesn't seem to be slowing as the amount of plastic created each year increases globally.

This study investigated (1) the effects of microplastic ingestion in the indicator species, the Pacific mole crab (Emerita analoga), testing the predator avoidance behavior, reproductive output and parasitism effects when an adult female gravid crab had ingested microplastics (2) adult mortality, hatching …

Solar Generated Electricity: An Analysis Of What Sectors Are Most Affected By Renewable Portfolio Standards And Related Policies, Logan Knollenberg

Dissertations and Theses

The aim of this thesis is to analyze state-specific Renewable Portfolio Standards (RPS) to understand their design and spillover effect onto non-utility (commercial, residential, industrial) sectors. Past research has overlooked non-utility sectors, often focusing on overall renewable energy growth and electricity generation from a combined end-result perspective. Solar capacity and solar generated electricity data from 5 states are used to establish which non-utility sectors experienced the highest level of solar growth from RPSs and related policies between 2010 and 2019. An explanatory sequential design is utilized, where interrupted time series analyses and exploratory case studies are performed to analyze each …

Forest Fire Effects On The Temporal Variability Of Landscape Snow Albedo Relative To Burn Severity, Max Gersh

Dissertations and Theses

Snow-water storage is decreasing, while forest fires are increasing in duration, size, frequency, and intensity, due to climate change. Most forest fires occur in the seasonal snow zone, altering snow mass and energy balance for many years following fire. Following forest fires, Surface snow albedo (SSA) decreases, as light absorbing particles (LAP), particularly black carbon (BC) produced in forest fires get deposited throughout the snowpack, altering snowpack energy balance driving earlier snowmelt in burned forests. While SSA decreases, landscape snow albedo (LSA) increases following fire, as more of the snow-covered surface becomes visible beneath the burned forest canopy, brightening the …

Investigation Of Environmental-Friendly, Membraneless Hydrogen Peroxide Fuel Cells, Bao Nguyen

Dissertations and Theses

Human-induced climate change is one of the biggest threats to humanity in the 21^st century. This is caused by the increase in greenhouse gas concentrations in the Earth's atmosphere. The burning of fossil fuels is the primary cause of climate change. This problem can be addressed by replacing fossil fuels with fuel sources that have clean by-products and are cost-effective. For the last few decades, hydrogen (H₂) has been extensively studied as an alternative to carbon-based fossil fuels. Currently, H₂ still has many shortcomings for commercial applications. The photocatalytic production of H₂ still suffers from …

Exploring Linkages Between Landscape Patterns And Freshwater And Estuarine Bivalves In The Coast Range Of Oregon, Kaegan Michael Scully-Engelmeyer

Dissertations and Theses

Spatial configurations of landscape variables (biotic, abiotic, and socio-ecological) affect and are affected by ecological processes and species in watersheds. This dissertation explores relationships among landscape patterns, ecosystem processes and bivalve species dynamics in coastal watersheds in Oregon, USA. I approached this broad topic through two primary avenues of research: investigating cross-ecosystem threats from pesticide use in forestland management to downstream aquatic environments, and the landscape ecology of an at-risk freshwater mussel species.

Terrestrial land use activities present cross-ecosystem threats to riverine and marine species and processes. Specifically, pesticide runoff can disrupt hormonal, reproductive, and developmental processes in aquatic organisms, …

A Ground-Based Assessment Framework For Validating Diesel Particulate Emission Models And Applicability In Portland, Or, Kirsten Marie Sarle

Dissertations and Theses

Exposure to diesel emissions causes a range of health effects throughout the body, impairing; respiratory, cardiovascular, central nervous, renal, and cognitive systems. Diesel particulate matter (DPM) in Portland, Oregon is prevalent due to the layout of highly trafficked roadways, rail lines, and marine ports exposing a dense population to high levels of exhaust pollution. These high concentrations of ambient diesel emissions disproportionately impact minority and low-income populations.

Ground-based monitoring and modeling are two ways to assess ambient DPM. However, there are uncertainties in modeled DPM due to knowledge gaps in emissions inventories as well as lack of model validation against …

Modeling Cyanotoxin Production, Fate And Transport In Surface Waterbodies, Bernadel Rose Hintz Garstecki

Dissertations and Theses

Cyanobacteria exist throughout the world and are frequently associated with forming toxic blooms. The toxins produced by cyanobacteria, cyanotoxins, are harmful to both humans and animals. Rising temperatures due to global climate change, increased nutrient loading, and other anthropogenic impacts on waterbodies are expected to increase the prevalence of cyanobacteria. It is vital that we protect our drinking water supplies and natural water resources. Modeling the production and movement of these toxins is an important step in limiting exposure to them and evaluating management strategies to mitigate their impact. Cyanotoxins are diverse and the conditions under which they are formed …

Rowing Concerns: Collaborative Governance And Stakeholder Determination In The Central Oregon's Deschutes Basin, Noel Vineyard

Dissertations and Theses

In 2019, a coalition of irrigation districts in central Oregon's Deschutes Basin submitted the Deschutes Basin Habitat Conservation Plan to the US Department of Fish and Wildlife. This Habitat Conservation Plan purported to have been constructed through a collaborative governance structure between the irrigation districts and various community stakeholders who all had interests in basin management, however segments of the Basin's river recreation community began to raise concerns that their voices were not included. The purpose of this research was to investigate how stakeholder status in the Deschutes Basin is created through collaborative water governance processes like development of the …

Agency, Sense Of Place, And Knowledge On The Zumwalt Prairie: A Social Study Of Place-Based Conservation And Resilience, Dana Elyse Hellman

Dissertations and Theses

Shifting and often diminishing environmental conditions, due to climate change, resource loss, and ecosystem degradation, pose a significant concern to both social and ecological systems. The field of conservation science has attempted to address environmental threats through varying approaches, transitioning from fortress conservation and complete human exclusion to community-based and co-managed models which incorporate human actors and social dimensions in the conservation process. The latest iteration of conservation scholarship, place-based conservation, is deeply rooted in interdisciplinary, social scientific thinking, and calls for significant practitioner engagement with local knowledge, practices, social constructions, and place meanings. It is an approach which emphasizes …

Urban Lakes: Ecosystem Services And Management, Laura Costadone

Dissertations and Theses

Lakes provide a variety of ecosystem services and benefits that greatly contribute to urban sustainability. Despite the growing interest in integrating freshwater systems into management and policy decisions, urban lakes are often overlooked in land-use planning. Nutrient and pollutant runoff from the surrounding urbanized watershed result in water quality deterioration that negatively impact the lake ecological functions and related ecosystem services. The vulnerability and degradation of these urban ecosystems should be a matter of concern, especially considering that, in rapidly growing metropolitan areas, the demand for aesthetic and recreational services provided by urban lakes is increasing. The overall goal of …

The Use Of Mayflies, Stoneflies And Caddisflies As Indicators Of Fine Sediment Pollution In Salmon-Bearing Streams Of The Pacific Northwest, Cory Michael Mccaffrey

Dissertations and Theses

Fine sediment (particles < 2 mm in diameter) deposition is a natural component of streams but in excess amounts it is harmful to aquatic biota. Fine sediment is the main cause of impairment in streams and rivers of the Pacific Northwest and it can lead to unsuitable spawning and rearing habitat for Endangered Species Act (ESA) listed Salmon and steelhead. From a regulatory perspective, fine sediment presents a challenge because it is difficult to measure in situ and to establish criteria that would indicate stream impairment. Consequently, there is considerable effort to develop biocriteria using stream macroinvertebrates that would help regulators determine if a stream is impaired by excessive fine sediment.

Stream macroinvertebrates are widely used to monitor and assess stream degradation because they are affected by the physical, chemical and biological conditions in a stream. In particular, the stream insects known as mayflies (Ephemeroptera, E), stoneflies (Plecoptera, P) and caddisflies (Trichoptera, T) are commonly used as a metric referred to as EPT richness. EPT taxa are well known as pollutant intolerant …

The Perceptions Of Rural Teachers Engaged In Environmental Education Professional Development Workshops: A Case Study Of The Alder Creek Community Forest And The Story Of Your Place, Bryan R. Benz

Dissertations and Theses

Environmental issues can be difficult for people to understand and for teachers to address in their classrooms. Issues such as climate change and ozone depletion are difficult to comprehend and present a challenge for most people to understand thoroughly the complexity of these environmental challenges. Professional development programs could provide the tools for teachers to improve their environmental literacy and a pathway for learning new methods for engaging their students. However, in rural Oregon, where professional development opportunities are scarce, teachers rely on a lean supply of organizations to provide these experiences. Alder Creek Community Forest, a nonprofit organization, provides …

Investigating The Effect Of Electrolyte Concentration And Charging Protocol On Materials Utilization In Rechargeable Zinc Manganese Dioxide Batteries, Snehal H. Kolhekar

Dissertations and Theses

Achieving a highly cyclable, high energy density battery with MnO₂ cathodes encounters many obstacles. Chief among these is the inability of the widely-used γ-MnO₂ polymorph to retain its structural integrity when cycled to near full one-electron discharge capacity, which is about 280mAh/g for commercially available electrolytic manganese dioxide (EMD). In this one-electron range, discharge occurs by proton insertion producing Mn⁺³ which then reverts to γ-MnO₂ on charging. In the first part of the thesis, we investigate the root cause of failure of MnO₂ cathodes under deep cycling in the one-electron discharge range and establish a …

Analysis Of Uncertainty In Hydrometeorological Ensemble Forecasts, Carolien N. Mossel

Dissertations and Theses

Ensemble hydrometeorological forecasting has great potential for improving flood predictions and use in water management systems, however, the amount of data used and created with an ensemble forecast requires a careful and intentional approach to understand how useful and skillful the forecast is. The NOAA National Water Model (NWM) was run using downscaled NOAA Global Ensemble Forecast System (GEFS) meteorological forcings for the 2016-2017 wet season (October-March) in California to create an 11-member hydrologic forecast ensemble. To evaluate the performance of these ensemble forecasts, we chose to study streamflow sites within Sonoma County, California, a rain-dominated region which includes the …

Understanding The Effect Of Climate And Hydrometeorological Extremes On Natural And Human-Induced Hydrosystems, Jeongwoo Hwang

Dissertations and Theses

The contemporary hydrosystems of the United States involve a complex combination of natural and modified basins in the presence of changing climate and anthropogenic impacts. An enhanced understanding of the interdependence between climate forcings, human-induced interventions, and water balance in both natural and modified basins are essential for developing reliable and resilient hydrosystems and for better water resources management. In response, this dissertation focuses on investigating the hydroclimatology of natural and modified basins across the contiguous United States. It has three research objectives: (1) to explain flow alterations due to anthropogenic activities, especially dam operations, in modified basins and understand …

Long Term Nutrient And Chlorophyll A Dynamics Across Long Island Sound And Impacts On Dissolved Oxygen Conditions Within The Western Sound (1991-2019), Sherry Perreira

Dissertations and Theses

Nitrogen overload, eutrophication, and hypoxia have been challenging and persistent water quality problems in Long Island Sound (LIS) over the past decades with major impacts on commercial industries, ecology, and recreational activities in the region. Recognizing these problems, the EPA enforced three phases of the Clean Water Act (CWA) to reduce nitrogen loads in an effort to improve this important estuary. This study examines how nitrogen (NH₃, NO_x & TDN), chlorophyll a (CHLA), and dissolved oxygen (DO) concentrations changed in LIS over the past 30 years, in response to water quality regulations as well as changes in …

On The Improvements Of Boundary-Layer Representation For High Resolution Weather Forecasting In Costal-Urban Environments, David Melecio-Vazquez

Dissertations and Theses

As large urban centers around the world become more densely populated, the global conversion from natural to man-made land surfaces will only increase. These land-use changes affect the urban surface energy budget which in turn changes the structure of the planetary boundary layer (PBL) above. With current high-performance computing systems, meteorological and built environment information can be better utilized to quantify the anthropogenic effects of these modifications. Although these systems have improved forecasting near-surface weather conditions, a comprehensive approach to represent urban impacts on the PBL is still limited. Improved PBL representation can lead to better weather and climate forecasts, …