Physical Sciences and Mathematics Commons^™

Deglacial And Holocene Environmental Change Recorded In Lake Sediments From The Snowy Mountains, Kosciuszko National Park, Southeastern Australia, Emma J. Mickelson

WWU Graduate School Collection

The sediment record from Lake Albina, the Snowy Mountains, southeastern Australia suggests significant environmental change mostly reflecting shifts in climate from the LGM through the Holocene. Immediately following deglaciation, approximately 19.4 thousand cal ky BP, Lake Albina experienced cold and/or dry conditions with minimal vegetation in the catchment. Cooler conditions persisted with a slight increase in moisture throughout the Antarctic Cold Reversal (ACR; 14.7-13 cal ky BP) aligning closest with a strengthening of the Atlantic Meridional overturning circulation (AMOC) and a northward shift of the South Westerly Winds (SWW). Between 12.9-9.7 cal ky BP, Lake Albina recorded a climate reversal …

Using Camera-Monitored Sediment Traps To Evaluate Sediment Availability And The Role Of Waves In Resuspending Seafloor Sediment, Bellingham Bay, Wa, Liam Horner

WWU Graduate School Collection

Understanding nearshore sediment budgets and processes is important for evaluating coastal hazards, habitats, and contaminant fate to enable informed decisions in coastal planning and management. I aimed to evaluate the role of waves in resuspending and redistributing sediments and by proxy contaminants in the urban/estuarine Bellingham Bay, and better understand the transport and rate of fluvial sediment moving through the nearshore. I integrated analyses using camera-mounted sediment traps, seafloor grain-size data, short-lived radioisotopes, and other fluvial, physical oceanographic, and wind data. I paired cameras with sediment traps, to identify the timing and rate of sedimentation on the seafloor at hourly …

Coupling Unoccupied Aerial System Surveys And Elevation Measurements To Predict Native And Nonnative Eelgrass Cover In Padilla Bay, Jacqui Bergner

WWU Graduate School Collection

There are two primary species of eelgrass at the Padilla Bay National Estuarine Research Reserve, Zostera marina, a native eelgrass, and Zostera japonica, a nonnative. Unoccupied Aerial Systems (UAS) have been frequently used for eelgrass monitoring and mapping, especially for large populations like those in Padilla Bay. UAS imagery have resolutions of 10 cm or better and are much more cost and time effective than aerial surveys via traditional aircraft that may provide similar image resolutions. In this project, multispectral UAS imagery was coupled with a centimeter level Digital Elevation Model (DEM), created from Real Time Kinematic GNSS …

Learning From Traditional Ecological Knowledge: Paralytic Shellfish Toxins In Butter Clams, Jackelyn Garcia

WWU Graduate School Collection

Anthropogenic forcing of marine ecosystems is disproportionately impacting Indigenous food systems and the health of coastal Indigenous communities. With increasing harmful algal events, there is rising concern for access and health of coastal communities who rely on shellfish for commercial, food, subsistence, and ceremonial harvest. In the U.S West Coast, the dinoflagellate Alexandrium spp. may produce paralytic shellfish toxins, which can cause shellfish to become toxic and is of especial concern. While recent research has led to greater awareness of the risks associated with paralytic shellfish toxins (PSTs), the concern for harmful algae is not new. Coastal Indigenous communities have …

Stereoselective Synthesis Of (+)- And (-)-Cananodine, Haley Holliday

WWU Graduate School Collection

Natural products are an important class of molecules utilized in traditional medicine and inspire drug design in medicinal chemistry. Cananga odorata, a tree commonly known as ylang-ylang, contains natural products known to positively benefit health, and specifically promote liver health. One alkaloid isolated from Cananga odorata, cananodine, possesses cytotoxic properties, specifically against hepatocellular carcinoma (HCC). HCC is the most common type of liver cancer, with one million diagnoses projected by 2025 globally. Cananodine is a member of the guaipyridine alkaloid family, a class of compounds that feature a substituted pyridine bonded to a seven-membered ring. The first enantiomer …

Structural, Mutational, And Kinetic Characterization Of Ura4, An Isocytosine Deaminase, Ashlee Hoffman

WWU Graduate School Collection

Cytosine Deaminases (CD) are a class of enzymes found in prokaryotes and fungi that have been studied in the past due to their ability to deaminate the prodrug 5-fluorocytosine (5-FC) producing 5-fluorouracil (5-FU). 5-FU is a common anti-cancer drug that can inhibit DNA synthesis leading to cancer cell death. 5-fluorocytosine can interact with digestive bacteria leading to unwanted side effects for cancer patients. Isocytosine Deaminases (ICD) are enzymes that are of interest in the treatment of cancers using Gene Directed Enzyme Prodrug Therapy (GDEPT). ICDs can deaminate the prodrug 5-fluoroisocytosine (5-FIC) also producing the drug 5-FU.  5-FIC will likely not …

Selectivity And Structure Of Chimeric Loop Swaps In Sh2 Domains, Sarah N. Smith

WWU Graduate School Collection

SH2 (Src Homology 2) domains are protein domains that bind to phosphorylated tyrosine residues within cell signaling cascades. They have been found to play a role in certain cancers and immunological disorders. Despite their importance in cell signaling and medical relevance, the structural basis of the various selectivity classes of SH2 domains is only partially understood. Previous research found that the EF and BG loops of the domains contribute to forming the peptide binding pocket, and thus impact their selectivity. To further understand the role of these loops in selectivity, we engineered chimeric SH2 domains by swapping the EF and …

New Synthetic Methods Based On Silicon-Tethered Nucleophilic Addition Reactions, Alexie W. Clover

WWU Graduate School Collection

With the recent discovery of an iodine mediated rearrangement of diallylsilanes, we set out to investigate a similar fluorine mediated rearrangement, aimed at introducing a new method for synthesizing organofluorine compounds. Interest in incorporating fluorine into organic molecules has grown significantly in recent years, primarily for medicinal applications. Since certain fluorination methods require the use of mCPBA, a common epoxidizing reagent, control experiments were performed on the reaction of several diallylsilanes with mCPBA, anticipating that a competing epoxidation of the diallylsilanes might occur. It was found that the formation of the hydroxy ester occurred through a regioselective epoxide opening from …

Regio- And Diastereoselective Samarium-Mediated Allylic Sulfone Reductions, Cody Schwans

WWU Graduate School Collection

A series of allylic sulfones were synthesized containing a stereodirecting group and chelating element and subjected to samarium diiodide reductions in the presence of a proton donor. The resulting products could be obtained with high regioselectivity (no less than 95:5) and high diastereoselectivity (>10:1) that correlated with the size of the stereodirecting group. A mechanism is proposed that includes loss of the sulfone and formation of a chelated organosamarium intermediate followed by intramolecular protonation by a samarium-bound proton source. In this way, both the regioselectivity and absolute stereochemistry of the resulting products are explained.

Tuned Gold Layer Growth Onto Plasmonic Sensing Silver Nanocubes Via Synthetic Control Of Reduction Potentials., Nicolas Hall

WWU Graduate School Collection

Metallic nanoparticles (mNPs) are commonly employed as sensors and detection tools due to their unique plasmonic properties. Silver NPs exhibit these properties in heightened capacity in comparison to other metals. However, Ag NPs are susceptible to oxidation, degradation over time and are biotoxic. These issues are commonly addressed by creating Ag-alloy NPs or by adding additional layers to Ag NPs. This work improves upon these methods by focusing on the growth of an Au layer onto Ag nanocubes (AgNCs), resulting in a layered Au-Ag NC (Au@AgNC). The resulting morphology of these Au@AgNCs are dependent on the synthetic pathway taken and …

Connections Between Eruption Style And Magmatic Reservoir Evolution: Insights From Augustine Volcano, Alaska, Usa, Mahinaokalani G. Robbins

WWU Graduate School Collection

At a single volcano, eruptive behavior can change through time as the plumbing system evolves. Augustine Volcano, a frequently active intermediate stratovolcano in the Alaska-Aleutian arc (USA), is an ideal setting to investigate magma reservoir processes due to its frequent modern and Holocene eruption history. Its most recent 2006 CE eruption included mixed effusive and moderately explosive (VEI 3) events and has been studied in detail. Proximal fall deposits from this eruption were generally mixed fine ash to lapilli with variable thickness, but typically ~5 cm on the island (Wallace et al., 2010). The Pre-contact “Tephra M” was deposited by …

Using Qm/Mm Methods To Explore Sortase Enzyme Intermediates, Kinetics, And Stability, Kyle Whitham

WWU Graduate School Collection

Biochemistry has seen advancements in methods and understanding of the inner workings of proteins, yet biochemists struggle to see real time reaction pathways of protein intermediates. This is where computational chemistry comes in and fills in the holes in knowledge through the use of Quantum Mechanical (QM) models. QM chemistry alone does not give results in a reasonable timescale to predict protein chemistry in a reasonable amount of time. Computational chemistry methods such as Quantum mechanical (QM)/ Molecular Mechanical (MM) (QM/MM), allow us to split the in-silico system into two regions that utilize a fast MM force field region and …

Generations Of Stewards: Re-Indigenizing Youth Leadership, Learning, And Conservation Education, Drew Slaney

WWU Graduate School Collection

My thesis is an exploratory case study into epistemologies (or worldviews) supported by organizations and agencies that develop outdoor conservation and education programs for Native youth called Native Youth Stewardship Programs (NYSPs). This subject relies on the content developed by Medin and Bang (2014) who state that an under-representation of Indigenous peoples in Science, Technology, Engineering, and Mathematics (STEM) fields is largely the result of epistemological conflicts between educators and Indigenous students. I hypothesize that there is a considerable epistemological difference between the conservation entities developing programs to engage Native youth. These differences may create significant barriers with youth recruitment, …

Evaluating Leaf Trait Variation In High Elevation Bristlecone Pine (Pinus Longaeva) Under Increasing Water Stress: Insights From Needle Length, Stomatal Density, And Cambial Growth, Audrey Salerno

WWU Graduate School Collection

Increasing aridification caused by climate change is altering growth patterns in trees. There is revived attention on how foliar traits respond to climate and the relationship of these traits to ring width. Bristlecone pine (Pinus longaeva, DK Bailey), a long-lived conifer found at high elevations in the cool and dry intermountain west of America, is used in paleoclimate reconstructions by measurement of their annually resolvable tree rings. The species also has annually datable needles retained on their branches for an average of 45 years making it the ideal subject for research on foliar trait and growth relationships under …

Class A Sortases: Structures And Alternative Substrate Binding And Cleavage, Brandon Vogel

WWU Graduate School Collection

Sortases, consisting of classes A-F, are cysteine transpeptidases found in the cell wall of Gram-positive bacteria. They play a crucial role in ligating proteins to the cell wall that are responsible for cell adhesion, immune evasion, host cell invasion, and nutrient acquisition through a transpeptidation reaction. Consequently, they are an attractive therapeutic target. Class A sortases are also utilized in protein engineering applications such as sortase-mediated ligations and sortagging. Despite extensive research in the past two decades, gaps persist in understanding how class A sortases recognize their substrates, primarily due to a lack of structural information on sortases non-covalently bound …

The Race Toward Carbon Neutral Ecotourism: Leveraging Life Cycle Analysis And Natural Climate Solutions For A Community Adventure Event, Ted Tarricone

WWU Graduate School Collection

Global tourism is an interconnected framework of multiple industries that is influenced by and has impacts on economic, social, and environmental structures. Currently, tourism accounts for roughly 8% of global greenhouse gas emissions, which is expected to grow with industry expansion. To develop a scalable system for ecotourism assessment, emission reduction, and solutions to meet carbon neutrality, a small (n=3894 participants) adventure relay race named Ski to Sea in Bellingham, WA was studied. A life cycle analysis (LCA) conducted on the race showed similar proportional results to other tourism LCAs, where transport made up over 80% of the 325 tonnes …

Contaminants Of Emerging Concern In Puget Sound: Screening, Prioritization, And Estrogenic Mixture Response Assessment, Maya Faber

WWU Graduate School Collection

Contaminants of emerging concern (CECs) are chemicals used in daily life, such as pharmaceuticals, personal hygiene products, steroids, pesticides, and flame retardants. The environmental occurrence and toxicology of CECs are poorly characterized, and they are generally unregulated. Traditional toxicological approaches rely on in vivo methods to test whole organisms for apical endpoints, including survival, reproduction, and growth. This is time-consuming and costly, both financially and in terms of laboratory animal well-being, limiting ecotoxicological data for CECs. To overcome this challenge, we are utilizing alternative approaches, including New Approach Methodologies (NAMs), to perform a screening-level evaluation of CECs present in Puget …

Trophic Transfer Of Metals From Seaweed To Shellfish In An Aquaculture System, Sophia Boyd

WWU Graduate School Collection

Seafood, including fish, shellfish, and seaweed, are an important source of nutrients that could meet some of the increasing demand for food globally. In addition to nutrients, chemical contaminants can also be acquired from the environment by primary producers. Seaweeds take up a variety of inorganic and organic contaminants, including metals, that may pose risks to human health. Through trophic transfer, organisms can accumulate elevated levels of contaminants from consuming lower trophic-level organisms. Since particulate organic matter, including seaweed detritus, is a food source for filter-feeding bivalves, contaminants present in seaweed could transfer to shellfish via ingestion. The purpose of …

Using Chemical Zoning In Minerals To Understand Magmatic Processes At Augustine Volcano, Alaska, Sloane Kennedy

WWU Graduate School Collection

The eruption behavior of a volcano is intrinsically linked to magmatic evolution. Augustine Volcano is an active stratovolcano in the Aleutian Arc (AK, USA), showing stratigraphic evidence that eruptions before 1,800 C.E. were more explosive, producing thick pumice deposits, compared to the six eruptions observed in the last 200 years. Tephra B, an understudied ~400-year-old pumice fall unit, represents the last more explosive style eruption at Augustine - making it ideal for studying how changes in magmatic evolution can result in changes in eruption style. For this thesis, I used textural zoning patterns and chemical variations (major and trace elements) …

U-Pb Zircon Geochronology And Structure Of Regional Blueschist Units In The Easton Metamorphic Suite, Northwest Cascades, Wa, Katherine Lang

WWU Graduate School Collection

The Easton metamorphic suite of the Northwest Cascades Thrust System (NWCS) is a well-preserved subduction accretion complex in Washington State. The regional blueschist units of the Easton metamorphic suite include the Mt. Josephine semi-schist, Darrington Phyllite, and Shuksan greenschist/blueschist and all are interpreted to have accreted after the onset of Jurassic subduction beneath North America. This study uses zircon U-Pb geochronology, structure, and field observations to test the regional correlations between units in the Easton metamorphic suite and address models for the timing of subduction accretion along the North American margin in the Late Jurassic – Early Cretaceous. The results …

A Mixed-Methods Study Of Geoscience Identity, Race/Ethnicity, And Gender In Senior Undergraduate Geoscience Majors, Willa Rowan

WWU Graduate School Collection

I conducted a mixed methods study of geoscience identity in undergraduate students to examine the cultural and social aspects of geoscience degree programs. White students are overrepresented in geoscience, and a priority of anti-racism efforts in the field is listening to the experiences of students who are Black, Indigenous, or people of color (BIPOC) to better inform equity and inclusion goals. Structural racism in geoscience pushes BIPOC students out of the field, and it can be better understood by studying socially constructed aspects of learning such as geoscience identity. This study is the first to measure geoscience identity with a …

Structural And Thermodynamic Studies Of Antibody Binding To Blood Coagulation Factor Viii, Jordan Vaughan

WWU Graduate School Collection

Blood coagulation factor VIII (FVIII) is a 2332 residue glycoprotein expressed in endothelial cells and plays a significant role in the formation of blood clots. Structurally, FVIII’s domains are organized as A1-A2-B-A3-C1-C2. The absence or deficiency of FVIII in the bloodstream gives rise to Hemophilia A; an X-linked bleeding disorder affecting 1 in 5000 males worldwide. To combat this deficiency, patients undergo FVIII replacement therapy which involves frequent injections of FVIII into the bloodstream in the form of blood, plasma, or protein concentrates. Although effective, this treatment commonly results in the development of anti-FVIII inhibitory antibodies in approximately 20-30% of …

Biomarker Study Of Bellingham Bay : Identifying How Urbanization Has Affected Carbon Storage And Eelgrass, Jess Shulman

WWU Graduate School Collection

Understanding sediment sources and fluxes throughout coastal zones is essential to evaluate shoreline stability, ecosystem health, and the potential for carbon storage. In Bellingham Bay, WA, like many developed coastal settings, urban areas have replaced forested cover and altered sediment fluxes, yet little is known of their offshore impacts. I analyzed n-alkanes, found in plant leaf waxes preserved in marine sediments of Bellingham Bay to characterize sediment sources and reconstruct changes in the relative contributions of eelgrass beds to sedimentary organic matter since pre-industrial times using a linear mixing model. Eight 2-meter-long cores were analyzed in order to determine how …

Investigating Kīlauea’S 2018 Offshore Lava Emplacement Through Hydroacoustic Data, Olana Costa

WWU Graduate School Collection

The 2018 eruption of Kīlauea Volcano produced an unprecedented volume of lava, creating 3.5 km² of new land on Hawai`i’s Big Island (Soule et al., 2021). Lava expelled from the Ahu`aila`au vent (originally called Fissure 8) traveled ~13 km to where it entered the ocean. Over half of the lava erupted in 2018 was emplaced offshore where it produced four new submarine lava deltas (Soule et al., 2021). In response to the eruption, a network of 12 ocean-bottom seismometers (OBS) with attached hydrophones was deployed on Kīlauea’s submarine south flank. Ten of the instruments successfully recorded data from July …

A Characterization Of Hyporheic Temperatures With Applications For Salmon Habitat Restoration In A Thermally Impaired River, Sydney Jantsch

WWU Graduate School Collection

This thesis project is part of an ongoing study assessing the effectiveness of a potentially innovative habitat restoration strategy for Pacific salmon in thermally impaired rivers. This strategy uses engineered log jams (ELJs) to create pockets of cool-water refuge by forming deep scour pools and promoting localized upwellings of shallow subsurface (i.e., hyporheic) water. This project seeks to characterize the relationship between hyporheic temperature and overlying surface stream temperature to elucidate the extent to which hyporheic upwellings can deliver cool water to ELJ-formed pools during the summer low-flow season. Among six sites within a 2.7 km-long study reach on the …

Visual Characteristics Of Walleye Pollock And Chinook Salmon: Modeling Theoretical Visual Space And Target Contrast Of Trawling Materials In The Bering Sea, Rebecca Haehn

WWU Graduate School Collection

Walleye pollock (Gadus chalcogrammus) and Chinook salmon (Oncorhynchus tshawytscha) are economic and cultural resources in Alaska. Chinook salmon bycatch is a large concern within the pollock fishery. Current strategies to reduce salmon bycatch include modifying trawl gear by implementing artificial light near or on escapement panels to increase salmon escapement. The visual characteristics of pollock and Chinook salmon were investigated to understand the perception of trawl gear. The visual pigments of each species were measured using microspectrophotometry (MSP). Pollock were dichromats with spectral sensitivity ranging from 449nm–518 nm and Chinook salmon were trichromats with sensitivity ranging …

Kinetic Analysis Of The Grafting Thermal Ring-Opening Polymerization Reaction Of Benzoxazine With Sulfonyl-Ester Functionalized Polymers, Tawakalt Adetoun Akinjobi

WWU Graduate School Collection

This project will explore the fundamental mechanistic details and kinetics of a grafting polymerization reaction that occurs with blended benzoxazine monomers (or resins) and polymers functionalized with reactive sulfonyl-ester leaving groups [such as tosylate (Ts), nosylate (Ns) or mesylate (Ms) groups]. Isoconversional analysis (ICA) is one of the most important methods for establishing the kinetics of the complex reactions associated with curing thermosets. In the case of ICA, activation energy is measured at fixed values of reaction conversion.²⁶ For thermosets the data are typically based on differential scanning calorimetry (DSC). The combinatorial approach not only provides uncertainty associated with …

Quantifying Channel Change Following Post-Fire Debris Flows In A Steep, Coastal Stream, Big Sur, California, Telemak Olsen

WWU Graduate School Collection

Debris flows commonly occur following wildfire in steep landscapes, introducing large volumes of sediment to downstream fluvial systems. Fire-related sediment supply perturbations impact channel morphology, and importantly, fragile aquatic and riparian ecosystems downstream of disturbance. The Big Creek watershed drains 57 km² of steep chaparral and coast redwood forest along California’s Central Coast. Streams in the Big Creek watershed typically exhibit step-pool/cascade morphology and serve as vital spawning habitat for anadromous Steelhead Trout (Oncorhynchus mykiss). In 2020, 97% of the Big Creek watershed burned in the Dolan Wildfire. In January 2021, an atmospheric river event triggered a series of …

Modeling The Effects Of Projected Climate Warming On Stream Temperatures In The Stillaguamish River Basin, Emily E. Smoot

WWU Graduate School Collection

The Stillaguamish River is a snow-and-rain mixed basin and the fifth largest river in the Puget Sound basin. Elevations in the 1700 km² Stillaguamish River basin reach roughly 2000 m and historically a snowpack is sustained above 1000 m. Snowmelt in the basin is important for sustaining spring and summer streamflow and buffering stream temperatures. Stream temperature increases are of significant concern because of the threatened Chinook salmon (Oncorhynchus tshawytscha) population.

I reexamined projected stream temperatures in the Stillaguamish River by forcing the coupled Distributed Hydrology Soil Vegetation Model and River Basin Model with dynamically downscaled meteorological …

Reconstructing Wildfire Regime During The Warm Paleocene-Eocene Climate Using Molecular Biomarkers From The Chuckanut Formation In Northwest Washington, U.S.A., Alexandra Thompson

WWU Graduate School Collection

Wildfires are expected to increase in frequency and severity as climate changes in the Pacific Northwest of North America. To better understand the effect of warming climate on wildfire regimes, I present the first reconstruction of past wildfire frequency and severity during the Paleocene-Eocene transition in northwest Washington state, U.S.A. The Chuckanut Formation is a late Paleocene to Eocene sedimentary unit with a robust paleobotanical record showing the existence of subtropical forests in northwest Washington during the Paleocene, transitioning to a relatively cooler Eocene, dominated by temperate mixed forests. Geochemical records of environmental change coinciding with Paleocene-Eocene climatic change in …