After over two decades of advocacy and planning, the four hydroelectric facilities on the Klamath River will be decommissioned and removed starting in 2023. Significant positive changes are expected to result, from reduced severity of Harmful Algal Blooms (HABs) to nearly a two-fold increase in accessible habitat for native salmonid...
Accurate estimation of water stress in vineyards could prove vital for optimizing irrigation and grape quality in a changing climate. The ECOsystem Spaceborne Thermal Radiometer Experiment on the Space Station (ECOSTRESS) offers potential to remotely sense vineyard water stress but lacks validation against in-field measurements in vineyards. In this study,...
From my personal experiences, I’ve noticed that Latinx students and families are most receptive to college-related information communicated as anecdotes. Latinx students are among the most poorly represented demographic at universities nationwide, which I believe can be mitigated through calculated efforts to increase collegiate literacy and understanding. This project is...
This study assessed suitability of annelid habitats under current baseflow conditions and evaluated the mobility of suitable annelid substrates under a 2-year peak flushing flow. Outputs from a 2020 Bureau of Reclamation SRH-2D model were combined with field measurements of annelid presence/absence and habitat variables including depth, velocity and d50,...
This study investigates the occurrence of beaver (Castor canadensis) in lentic habitat (lakes and ponds) near Mount St. Helens in Washington, 40 years after the 1980 eruption. At the coarse spatial scale, I surveyed lakes for sign of beaver establishment (lodge or den) across multiple volcanic disturbance zones. At a...
Accurate estimation of the amount of water used by trees is important for a variety of agricultural applications. There are several current methodologies for measuring sap flow and water use in trees, however the heat ratio method has been identified as the ideal due to its ability to measure low...
The National Ecological Observatory Network (NEON) provides open access data products including sub-daily precipitation amounts and biweekly stable water isotope concentrations at sites across the United States. Stable water isotope (ẟ2H, ẟ18O) concentrations are often used in hydrometeorological studies and models, however the relatively infrequent biweekly sampling intervals of NEON...
Plant nurseries comprise the largest agricultural sector in Oregon at nearly $1 billion per year. Even at this scale, individual nurseries and greenhouses do not have clear water quality standards set by the EPA. Watershed-level total maximum daily loads (TMDLs) have been set for excess nutrients and herbicides due to...
This study was conducted to determine if bacterial DNA present streams could be used to predict upstream watershed characteristics. Previous studies have found that bacterial composition in soil is influenced by land use. It was hypothesized that if the bacteria present in a stream is known that it can be...
Research in geoscience often requires transmission of significant amounts of data from remote locations. The emergence of microcontrollers and open-source sensors are allowing connectivity to affordable, distributed in-situ monitoring. This report describes the OPEnS Hub, a modular data hub orders of magnitude cheaper than commercial dataloggers when scaled to multiple...
This study was conducted to determine if a time-integrated Phillips sampler was able to estimate sediment yield when compared to a reference produced by an automated sampler. Time-integrated samplers are easier to use, more cost effective, and can withstand storm events better than automated samplers, but are not designed to...
In the face of increasing demand for and reduced supplies of water, methods to augment water supply and storage capacity are becoming increasingly important. In some areas, this has taken the form of aquifer storage and recovery (ASR), which involves injecting water into a well during a time of water...
Floods remain the world’s most destructive natural hazard, despite centuries of efforts to minimize losses. Understanding public preferences for flood mitigation measures, and the impacts of these measures, is key to minimizing flood-induced losses. This study quantified tradeoffs between flood mitigation measures and determined factors that influence public preferences for...
Liquid manure lagoons are known to be sources of odor and environmentally damaging gas emissions. Land application of the manure slurry after storage can lead to detrimental nutrient runoff and leaching. Floating lagoon covers (biocovers) are one option for reducing emissions, but to date they have only been used to...
How water moves through soils is of importance to studies of stream hydrology and biogeochemistry. Although translatory flow, which states how soil water is displaced by additional precipitation into streams, is a widely accepted model, Brooks et al. (2010) found evidence that challenged this model. They suggested that there are...
This study is a preassessment of the ecological status of habitats and species potentially affected by wave energy device installation, focusing on five flatfish species. Butter sole (Isopsetta isolepis), English sole (Parophrys vetulus), Sand sole (Psettichthys melanostictus), Pacific sanddab (Citharichthys sordidus), and Speckled sanddab (Citharichthys stigmaeus) were collected bimonthly from...
Estimating how large instream wood (LW) may impact local hydraulics is critical both for mitigating flood hazards and for ensuring intended habitat benefits of the LW are produced. In practice, the design of forms such as LW is limited by a lack of mechanistic tools for estimating how LW features...
Diking and channelizing in the Toppenish Creek basin, associated with irrigated agricultural development, has altered its natural ecosystem function and hydraulic processes. We seek to answer two research questions: if surface waters are diverted for aquifer recharge in the winter, will this water be available for ecosystem function in the...
Wildfire management networks allow for collaborative intervention in mitigating the ever-present risk of major wildfire events. This thesis consists of two manuscripts that explore the topology and characteristics of wildfire management networks and their ability to influence wildfire severity in social-ecological systems. The first manuscript focuses on the characteristics of...
The objective of this study is to evaluate the potential of removing organic carbon and inorganic nitrogen contaminants, and metals from the leachate prior to any land application. New guidelines are needed to ensure the environment and our health is not put at risk. The cost of installation, operation and...
Agricultural systems are inherently complex; understanding these systems requires knowledge of climatology, plant physiology, soil physics, economics, and the human psychology of the farmers themselves. Decision support tools strive to leverage existing data to help guide stakeholders towards the best policies and practices for their situation. Quantitative crop simulation models...
Water bodies act as chemical data loggers that contain tens of thousands of molecules that represent the sum of the biological, chemical, and physical processes occurring within a watershed. We hypothesize that unique chemical signatures present within a water sample can be informative of upstream processes. By extracting non-polar organic...
Biological hydrogen production from renewable feedstocks was reckoned as a promising method for sustainable energy production. Bioelectrochemical hydrogen production using microbial electrolysis cells (MECs) demonstrated superiorities over the conventional methods for hydrogen production. The introduction of the membrane-less single chamber design further improved the feasibility of MECs for practical application,...
Growing populations and industrialization rates across the world are leading to increased food and energy demand. The challenge of meeting this demand while also mitigating climate change impacts serves as a driving force for the development of renewable energies technologies. This study focuses on the role of Agrivoltaic systems in...
Enzymatic hydrolysis is a critical process in the conversion of lignocellulosic biomass into biofuels and biochemicals. Achieving high efficiencies and productivity during the enzymatic hydrolysis of biomass is the key for the commercially viable process. Downstream processing challenges require high product titers which in turn require the use of high...
Urban stormwater runoff contains pollutants that have a detrimental effect on pond water quality and watershed water quality. Stormwater best management practices (BMPs), such as a constructed wetland, can treat these pollutants through processes like infiltration, adsorption, and plant uptake. It is hypothesized that the surface-runoff fed pond at Bruce...
Biohydrogen production via dark fermentation (DF) and microbial electrolysis cells (MEC) demonstrate great potential for sustainable hydrogen generation. In this study, DF and MEC were coupled as a hybrid reactor and evaluated using brewery wastewater. The effect of hydraulic retention time (HRT) and buffer concentration on reactor performance were assessed...
1. To determine whether plastics are being ingested by black rockfish at three sites along the Oregon coast
2. To determine if there is a significant difference in rates of plastic ingestion between marine reserve locations and Newport location.
3. To quantify the extent of plastic ingestion and to identify...
Modification of microbial electrolysis cells (MECs) by altering the sizes of the anode and the cathode, or their interaction with the liquid stream affects the performance of the MEC, but it remains difficult to quantify how much each change will contribute to the overall performance. Through this study, a method...
The economically viable production of value added fuels and chemicals from lignocellulosic feedstocks hinges on our ability to quickly and efficiently transform structural carbon molecules to end products. The sugars in lignocellulosic biomass are held primarily within cellulose and hemicellulose. Cellulose is composed primarily of glucose monomers which are quickly...
The complex, dynamic nature of microbial communities in both natural and engineered environments complicates the work of scientists and engineers who wish to channel microbial interactions for societal good. The successful management of these communities towards engineering goals is dependent on developing predictive linkages between community structure and functional outputs....
Fossil fuels have been the main source of energy for a long period but due to growing concerns over climate change, oil depletion and energy security, the development of renewable sources of energy such as biofuels have been flourishing over the past few decades. Despite the fact that biofuels are...
Photo voltaic solar energy is a clean source of energy with much lower carbon footprint than other sources. However, the vast land requirements of solar energy arrays may make installation impractical when available land is better suited for other purposes. The goal of this research was to investigate changes to...
Further enhancement of energy generation is desired for practical application of anaerobic microbial systems such as microbial fuel cells (MFC) and anaerobic digesters (AD). A possible approach is to enhance the ability of microbial communities to transfer electron extracellularly in the form of electrical current. Critical to perform direct extracellular...
The thesis documents research about combining the National Pollutant Discharge Elimination System (NPDES) Permit Program with the Impact 2002+ methodology to conduct a Life Cycle Assessment (LCA) for wastewater treatment processes. The LCA for the operational phase of a local wastewater treatment plant was performed and the environmental impacts caused...
Attributional and consequential life cycle assessments are useful in evaluating the environmental impacts of a process, product, or decision. Both types of life cycle assessments differ however in their scope and their ability to answer specific questions. In order to fully understand and compare the environmental impacts of a sugarcane...
Microalgae has been under careful consideration as a sustainable feedstock for renewable fuel recently due to its year round production with high energy yields per unit area, reduced need for arable land, water treatment benefits with nutrient cycling, and minimal competition with the food industry. Despite of all these advantages,...
The Open Modeling Environment (OME) is a tool developed to address some known shortcomings in ecological System Dynamics (SD) modeling research. OME provides a common set of methods for interacting directly with spatial information, reducing the need for modelers to create their own methods for doing so. The environment is...
Developing new wastewater treatment technologies which will off-set the high-energy cost associated with treatment is necessary to maintain both water and energy security. Microbial fuel cell technology represents one such option. However, there are still many obstacles to overcome before practical application of this technology can be realized. Improving cathode...
Ethanol production from lignocellulosic feedstock has been under intense scrutiny as a transportation fuel due to its potential to address concerns of increasing energy consumption, limited fossil energy resources, climate changes due to greenhouse gas emissions from fossil fuels, and especially use of non-food biomaterials, which address the biggest limitation...
The production of fuel ethanol from lignocellulosic biomass has the potential to replace a significant portion of non-renewable transport fuels. Woody feedstocks are composed of cellulose, hemicellulose, and lignin. Glucose, the monomer of cellulose, is readily utilized by wild-type S. cerevisiae, but xylose, which comprises 60% of the sugar in...
Photobiological hydrogen production -- the use of photosynthesis to split water into hydrogen and oxygen -- presents an opportunity for efficient and large-scale solar biofuel development. One of the major challenges in this area is competition for reductant between the hydrogen-evolving hydrogenase enzyme and other metabolic pathways. In this work...
Water conservation and water quality are rapidly increasing in importance in all areas of the world. The ability to accurately measure soil water content and salinity, over a wide variety of conditions, is key to meeting this need. A set of forward prediction models and waveform interpretation algorithms to extract...
Microbial electrochemical systems (MESs) have attracted much research attention in recent years due to their promising applications in renewable energy generation, bioremediation, and wastewater treatment. In a MES, microorganisms interact with electrodes via electrons, catalyzing oxidation and reduction reactions at the anode and the cathode.
The bacterial community of a...
This document describes the design and deployment of a first generation water vapor density sensing unit, the HumiSense. This device is based on an open, air-filled capacitor which is part of a resonant circuit. The frequency of the resonant circuit mixed with a fixed frequency oscillator is the basis of...
Many regions in North America are experiencing water shortages, and these conditions are expected to worsen. The next generation of irrigation scheduling applications must therefore be capable of providing operational advice in support of deficit irrigation strategies. However, the theoretical, technical, and practical challenges associated with deficit irrigation scheduling are...
Shewanella oneidensis MR-1 is a gram-negative, facultative anaerobic bacteria with the capability of dissimilatory metal reduction. The ability of the organism to reduce a wide range of solid metal-oxides during anaerobic respiration makes it an ideal candidate for the powering of microbial fuel cells (MFCs), which capture the electrons discharged...
Energy use and greenhouse gas emissions are on the forefront of planning policy in the world today. In the U.S., the transportation sector accounts for 50 percent of greenhouse gas (GHG) emissions, the most of any single sector. State and local levels of government have been very proactive in the...
Upper Klamath Lake (UKL) and Agency Lake (AL) in southern Oregon are both hypereutrophic, in large part due to natural and anthropogenic loading of phosphorus (P), resulting in annual blooms of blue-green algae. Reduction of P loading to the lake is considered crucial to reduce the blue-green algae blooms, maintain...
Photobiological hydrogen production from live cells of the cyanobacterium Synechocystis sp. PCC 6803 encapsulated in silica gel was investigated. Hydrogen is a dense energy carrier with potential to reduce dependence on fossil fuels, provided a renewable and sustainable means of production can be achieved. Under certain conditions, Synechocystis sp. PCC...
Pure glycerol and the crude waste glycerin byproduct of biodiesel production were tested as substrates for electricity production in single-chamber, air-cathode microbial fuel cells (MFCs) and in single-chamber microbial electrolysis cells (MECs), using pure and mixed microbial cultures as anode biocatalyst. Current densities of 0.40 A/m² and 0.13 A/m² were...
Cellulosic ethanol production for transportation fuel is one source to help satisfy the increasing worldwide demand for energy and depletion of the fossil fuel supply. Evaluating potential production from plants and waste in Oregon, Washington and Idaho is the purpose of this study. Reed Canary grass, Annual Ryegrass, wheat straw,...
A major challenge in ethanol production using lignocellulosic feed stock is
inefficient utilization of hemicellulose, which accounts for 30-40% of lignocellulosic
biomass. Xylose, comprising >60% of recoverable sugars from hemicellulose is a
major product of the hemicellulose hydrolysis. Utilization of this carbon source would
significantly increase the ethanol yield from...
The thermophilic cyanobacterium Thermosynechococcus elongatus was examined for the ability to sequester CO₂ while producing hydrogen (H₂), polyhydroxybutyrate (PHB), lipids, and glycogen. H₂ was produced at a maximum rate of 188 nmol H₂ mg Chl a⁻¹ hr⁻¹. Hydrogen production occurred in the presence of methyl viologen but the cells were...
This thesis documents the work carried out investigating the downstream processing of algal biomass for biofuel production. A life cycle assessment was conducted on a hypothetical algal biodiesel process in which it was found drum drying and cell component separation were life cycle intensive processes. A
laboratory experiment was conducted...
Microbial electrolysis provides a new approach for hydrogen generation from renewable biomass. At current stage, the most likely limiting factors for successful scale up of this technology are the large internal resistance and high fabrication cost. This dissertation presents an attempt to overcome these limitations by investigating novel microbial electrolysis...
The vegetation in Yosemite National Park changed during the 20th century and may change in the 21st century in response to climate change. Vegetation surveys made during the 1930s and the 1990s provide benchmark records separated by 60 years. This study uses the MC1 dynamic global vegetation model to forecast...
Many conditions affecting hydrogen (H₂) production by the cyanobacterium, Synechocystis sp. PCC 6803, were optimized to yield maximum H₂ accumulation. Biological H₂ production from photosynthetic species is a promising form of renewable energy since an abundant supply of sunlight hits the Earth every day, and photosynthetic bacteria can harness this...
The gravel aquifer of the Oregon side of Walla Walla River Basin has a strong hydrologic connection to surface water through a series of springs, unlined irrigation canals, the Walla Walla River, numerous wells and, since 2004, artificial recharge to the shallow aquifer using infiltration basins. The finite element Integrated...
Nitrosomonas europaea (ATCC19718) participates in the biological removal of nitrogen from wastewater by oxidizing ammonia to nitrite, the first step in nitrification. This bacterium is sensitive to heavy metals (Zn²⁺, Cd²⁺, Cu²⁺, and Hg²⁺) and cyanide, compounds commonly encountered in wastewater treatment plants. Therefore, we characterized physiological and transcriptional responses...
Agrivoltaics, which integrates photovoltaic power production with agriculture in the same plot of land, has the potential to reduce land competition and crop irrigation. To optimize agrivoltaic systems for crop growth, energy pathways must be characterized. While solar panels shade the crops, they also emit longwave radiation. At the end...
Drought represents an import part of natural hydrologic cycles that govern the rate and transportation of water on global and regional scales. (Trenberth, et al. 2015) Agriculturally, drought represents a threat to crop production and can endanger political and economic stability through the loss of resources and the threat of...
Dissolved organic carbon (DOC) flux is an important mechanism to convey soil carbon (C) from aboveground organic debris (litter) to deeper soil horizons and can influence the formation of stable soil organic carbon (SOC) compounds. Aboveground litter quantity and quality was manipulated for 20-years in an old-growth Douglas fir forest...
Abstract Watershed-scale fate/transport modeling of contaminants is a tool that scientists and land managers can use to assess pesticide contamination to stream systems. The Catchment Modeling Framework (CMF) is a catchment-scale fate/transport modeling tool. It was developed to help scientists and land managers assess the effects of possible land-use decisions...
The objectives of this project are to 1) evaluate the fish passage for Lamprey at the Alder Creek, Corvallis, OR using HEC-RAS, and 2) develop a worksheet for the scour analysis if the culvert is removed. Fish passage criteria from Oregon Department of Fish and Wildlife were applied to determine...
Interactions and feedbacks among climate change effects and continued human impacts will exacerbate impacts to water resources in complex ways. An urgent imperative of the hydrologic community is to understand the response of hydrologic systems to these perturbations, thus contributing to long-term sustainability of water resources in an uncertain future....
Survival of ecological systems pivot on critical moments. In the arid John Day Basin of Eastern Oregon, extensive restoration of the stream and floodplain focused on supporting salmon has been ongoing for the past 20 years, but recurring short periods of extreme temperature increase and low flows result in mortality...
Urban development causes changes in the hydrology, increasing stormwater runoff volumes, which often leads to flooding and ecosystem degradation. This is a common phenomenon in most urban Africa, due to lack of stormwater drainage infrastructures. Green Infrastructure (GI) has been shown to be an effective approach to lessen the effects...
While water scarcity and energy demand are continuously increasing in the world, alternative sources are needed to meet the requirement of a growing population. Microbial Fuel Cell (MFC) is a sustainable technology that converts organic matter in wastewater into electricity, thus it can be a potential alternative source for water...
We have sufficient evidence that our historical management of natural resources is not sustainable. Food production is stagnating or declining. Nonrenewable energy sources on which the energy sector has historically depended are being rapidly depleted. Water resources, for which the energy and food sectors compete, are being depleted and impaired....