Life Sciences Commons^™

The Fish Bites Back: A Developmental Analysis Of Feeding Biomechanics In Danionin Minnows, Collin Shinkle

WWU Graduate School Collection

Ecological roles are often closely related to the food organisms consume, and investigating the developmental control of feeding apparatus morphology and biomechanics contributes to a broader understanding of how ecological roles evolve. Changes in thyroid hormone signaling are thought to be involved in the evolutionary diversification of feeding mechanics in many fish lineages, including danionin minnows such as zebrafish (Danio rerio), a common model organism. Recent work suggests that changes in thyroid hormone signaling may have influenced the trophic divergence of fishes in the genus Danio and those in the genus Devario, including the giant danio ( …

Modeling The Impact Of Agricultural Management Practices On Riverine N Export In The Transboundary Nooksack River Watershed, Washington, Astoria Tershy

WWU Graduate School Collection

The eutrophication of fresh and coastal waters is a growing global concern. Agricultural best management practices (BMPs) mitigate nutrient pollution, but their effectiveness at the watershed scale is often untested, creating uncertainty around which practices should be prioritized. In the Salish Sea, on the Pacific coast of Washington State and British Columbia, seasonal hypoxia threatens food webs, already-impacted salmon populations, and tribal fishing rights. To what extent can different BMPs alleviate N export in watersheds with heavy agricultural influence? We used the InVEST^® Nutrient Delivery Ratio (NDR) model to estimate reductions in N export under BMP scenarios in the …

Can Larvae Of A Deep-Sea Gastropod, Thalassonerita Naticoidea, Swim To The Surface To Find Food In The Gulf Of Mexico?, Mitchell Hebner

WWU Graduate School Collection

For larvae of benthic organisms living in the deep-sea, the location where they begin their dispersal influences their vector of travel because ocean currents affect larval dispersal when the larvae are in the water column during a possible vertical migration. The deep-sea is food-poor when compared to the food-rich surface waters, but planktotrophic (feeding) larval development of deep-sea benthic organisms is common. Despite the potential need for planktotrophic larvae of deep-sea organisms to access more nutrient-rich food sources and knowing a larva’s position in the water column can impact larval transport, we have very little understanding of where in the …

Impact Of Fluctuating Temperature And Elevated Co2 On The Growth, Survival, And Metabolic Rate Of The Endangered Pinto Abalone (Haliotis Kamtschatkana) In The Salish Sea, Jaclyn Stapleton

WWU Graduate School Collection

Pinto abalone (Haliotis kamtschatkana) is the only abalone species found in the Salish Sea in the northeastern Pacific Ocean. They were recently declared as a State endangered species and human intervention is necessary to recover the species. Puget Sound Restoration Fund (PSRF) is one of the organizations trying to restore pinto abalone populations in the Salish Sea. Some of their outplant sites are less successful than others although they are physically similar. Currently, there is no research on how environmental variation affects juvenile pinto abalone survival, growth, and metabolic rate.

The goal of my thesis was to simulate …

The Effects Of Diatom-Specific Polyunsaturated Aldehydes On Larval Zebrafish (Danio Rerio), Rachel Raymer

WWU Graduate School Collection

Diatoms are ubiquitous in marine planktonic and benthic environments and are common in diets for many lower-trophic organisms. Certain species of diatoms produce polyunsaturated aldehydes (PUAs) that can exist in particulate and dissolved forms. Diatom PUAs are known for negatively affecting the fecundity of their primary consumers, including invertebrate grazers like copepods and echinoderms. However, little is known about the effects of diatom PUAs on vertebrates that may be exposed to dissolved or ingested PUAs due to overlapping distribution with diatom populations. The purpose of this study was to test whether dissolved diatom PUAs affect the early life stages of …

A Metagenomic Analysis Of The Microbial Communities Associated With Different Hydrothermal Vent Chimneys, Laura Murray

WWU Graduate School Collection

Hydrothermal vents host a diverse community of microorganisms that utilize chemical gradients from the venting fluid for their metabolisms. The venting fluid can solidify to form chimney structures that these microbes adhere to and colonize. These chimney structures are found throughout many different locations in the world’s oceans. In this study, comparative metagenomic analyses of microbial communities on five chimney structures from around the Pacific Ocean were elucidated focusing on the core taxa and genes that are characteristic for each of these hydrothermal vent chimneys, as well as highlighting differences among the taxa and genes found at each chimney due …

Polyunsaturated Aldehyde Production In The Salish Sea: A Survey Of Benthic Diatom Producers And The Influence Of Coastal Upwelling, Jeremy Johnson

WWU Graduate School Collection

In coastal, nutrient-rich waters like the Salish Sea, diatoms dominate the phytoplankton community during seasonal upwelling events. Diatoms were once believed to be an ideal food source for primary consumers like copepods, but their role in food web dynamics changed upon discovery that diatoms can produce organic compounds upon cell death known as polyunsaturated aldehydes (PUAs). These compounds directly affect the reproductive success of diatom consumers by reducing egg production and viability, deforming embryos, and delaying embryonic development. PUA production dynamics have been assessed under varying nutrient concentrations and culture age, but no study has tested the effect of elevated …

To Flee Or Not To Flee: How Range Dynamic Of Alpine Species Are Changing Through Time, Lian Noonan

WWU Graduate School Collection

In response to anthropogenic climate change, alpine floras in particular have been forecasted to shift their ranges upslope and north, yet recent analyses have shown otherwise. While a handful of floras have been found to track the trajectory of predictive models, most floristic elements have remained in their historical ranges despite a changing climate. Therefore, to improve the accuracy of models predicting range shifts, I address the following questions: (1) are mountain floras spatially structured through time; and (2) how are range dynamics of mountain floras changing through time. To address these questions, this study analyzed the herbarium records of …

Complex Microbial Mat Communities Used To Assess Primer Selection For Targeted Amplicon Surveys, Lindsey Smith

WWU Graduate School Collection

The microbiota of hydrothermal vents has been widely implicated in the dynamics of oceanic biogeochemical cycling. Lithotrophic organisms utilize reduced chemicals in the vent effluent for energy, which fuels carbon fixation, and their metabolic byproducts can then support higher trophic levels and high-biomass ecosystems. However, despite the important role these microorganisms play in our oceans, they are difficult to study. Most are resistant to culturing in a lab setting, so culture-independent methods are necessary to examine community composition. Targeted amplicon surveying, in which a marker gene is selected for DNA amplification, has become the standard practice for assessing the structure …

The Toxicity Of Dopamine On Salish Sea Phytoplankton, Allyson Lombardo

WWU Graduate School Collection

In the Salish Sea, blooms of the intertidal macroalgae, Ulvaria obscura, are common and can achieve extraordinarily high biomass. Upon desiccation and subsequent rehydration from incoming tides, U. obscura releases dopamine. Previous studies showed that dopamine negatively affects other macroalgal species and can deter grazers. However, the effects of dopamine on co-occurring phytoplankton remains unknown. This study explored the toxicity of dopamine on four phytoplankton known to inhabit the Salish Sea: the haptophyte, Isochrysis galbana; the chlorophyte, Dunaliella tertiolecta; the dinoflagellate, Heterocapsa triquetra; and the diatom, Thalassiosira sp. Over the course of 8 days, phytoplankton growth …

Interrogating Centrosome Protein Dynamics, Centriolar Satellite Regulation Mechanisms, And Autofluorescence Characterization Of Caenorhabditis Elegans Using Förster Resonance Energy Transfer-Fluorescence Lifetime Imaging Microscopy (Fret-Flim) And Fluorescence Microscopy, Elizabeth A. Cameron

WWU Graduate School Collection

Centrosomes are required for human cells to divide and differentiate into the many different embryonic tissues that form throughout development. Mutations that drastically disrupt centrosomes cause embryonic lethality and cancer. More subtle mutations cause congenital birth defects including blindness, olfactory deficits, and limb, heart, and brain malformations. PCNT is an essential human gene that encodes for the centrosome protein Pericentrin. Pericentrin organizes the structure of the centrosome by serving as a scaffold protein. Pericentrin also interacts with other centrosome proteins, which play a role in centrosome-mediated microtubule formation. Additionally, Pericentrin recruits enzymes that are involved in centrosome duplication and maturation, …

The Impact Of Polychlorinated Biphenyls On The Development Of Zebrafish (Danio Rerio), Megan Moma

WWU Graduate School Collection

Polychlorinated biphenyls (PCBs) are a group of 209 highly stable molecules that were used extensively in industry. Although their commercial use ceased in 1979, they are still present in many aquatic ecosystems due to improper disposal, oceanic currents, atmospheric deposition, and hydrophobic nature. PCBs pose a significant and ongoing threat to the development and sustainability of aquatic organisms. Our hypothesis is that PCB concentration will significantly affect development. Zebrafish (Danio rerio) were exposed to a standard PCB mixture (Aroclor 1254) for the first 5 days post fertilization, as there is a gap in knowledge during this important developmental …

Foraging Ecology Of Sexually-Dimorphic Marine Generalist Predators: Describing Stellar Sea Lion Diet Along The Northern Washington Coast, Zöe Kathryn Lewis

WWU Graduate School Collection

Understanding generalist predator impact on prey populations requires an understanding of predator diet composition, foraging ecology and specialization, all of which may vary over spatial and temporal scales. Steller sea lions (Eumetopias jubatus) are large, sexually dimorphic, generalist predators that may have different roles in the ecosystem based on sex. However, the variation between individuals within a population, or intrapopulation feeding diversity of Steller sea lions has not been examined. In this study, I describe the diet of Steller sea lions along the northern coast of Washington between December 2020-August 2021 using DNA metabarcoding, hard parts analysis, and qPCR sex …

Promoting Pinto Abalone (Haliotis Kamtschatkana) Recovery In The Salish Sea: The Effects Of Fluctuating Temperature And Elevated Co2 On Survival, Growth, And Radula Morphology, Elizabeth Janie Diehl

WWU Graduate School Collection

Overharvesting of pinto abalone (Haliotis kamtschatkana) in the Salish Sea between 1959 and 1994 caused severe population declines. This led to the Washington Department of Fish and Wildlife classifying pinto abalone as a “species of concern.” The Puget Sound Restoration Fund (PSRF) is committed to help pinto abalone recover by outplanting juveniles at specific sites around the Salish Sea. Survival of outplanted individuals is different at each site, but it is not clear why. Differences in water chemistry parameters, such as temperature and pH, could explain the differences in survival, either through differences in the mean conditions or through short …

The Heritability Of Mandible Length In The Zebrafish (Danio Rerio), Danielle K. Ringo

WWU Graduate School Collection

Jaw shape often plays a significant role in determining feeding niche. Changes to jaw development can alter feeding mechanics and affect an organism’s ability to acquire and/or process food. Derived patterns of jaw morphogenesis are therefore frequently associated with evolutionary shifts in trophic ecology. Changes in thyroid hormone signaling can have strong developmental effects on many aspects of vertebrate anatomy including the shape of the lower jaws. Zebrafish mutants (opallus^b1071) are hyperthyroid and typically undergo excessive mandible elongation. However, hyperthyroid opallus do not always develop elongated lower jaws. This mutant line was maintained at separate universities for …

The Effect Of Targeted Acoustic Startle Technology On The Foraging Success Of Individual Harbor Seals, Kathleen Anne Mckeegan

WWU Graduate School Collection

Rebounding pinniped populations have led to conflicts with fisheries over commercially important prey species. Acoustic deterrent devices (ADDs) are used to aid the recovery of depleted fish stocks by mitigating pinniped predation. However, most ADDs use painful sound signals, which can lead to hearing loss and habituation. Alternatively, a new ADD called Targeted Acoustic Startle Technology (TAST) decreases pinniped predation with no evidence of harm or habituation, but effects on the foraging success of individual pinnipeds is unknown. In the Salish Sea, harbor seal (Phoca vitulina) populations have rebounded since the early 1970’s and are suspected of impeding the recovery …

Geographic Variation Of Desiccation Resistance In Rhagoletis Zephyria (Diptera: Tephritidae) In The Pacific Northwest: An Adaptive Response To Local Bioclimate, Nathan Roueche

WWU Graduate School Collection

Species with broad distributions exist in heterogenous landscapes and therefore must be able to maintain key physiological processes under a variety of abiotic conditions. This can lead to localized variation in phenotypes associated with environmental cues. Atmospheric water loss is a major source of physiological stress for terrestrial insects and one which is predicted to have major implications for biodiversity under future climate scenarios. Understanding which species exhibit adaptive variation can provide crucial insights into how individual species and thus ecological communities have evolved to cope with changing climate conditions as well as inform predictions as to how they may …

Primary Cilia Display A Non-Uniform Response To Intracellular Calcium Release, Hannah R. Fisher

WWU Graduate School Collection

Cilia are microtubule-based organelles that project from the surface of individual cells. When cilia are formed, they are nucleated from centrioles that are known as basal bodies. Microtubules elongating from the basal body give rise to the axoneme of the cilium, which gives cilia their rod-like structure. The axoneme is surrounded by a specialized plasma membrane that is unique, but continuous with the plasma membrane that surrounds the rest of the cell. The ciliary membrane is enriched with ion channels and membrane-bound proteins that are essential for cilia function. Interestingly, the cilium maintains a distinct environment from the rest of …

Microbial Community Dynamics During Key Life History Transitions In The Deep-Sea Chemosymbiotic Mussel, Gigantidas Childressi, Tessa F. Beaver

WWU Graduate School Collection

Marine invertebrates form specific associations with bacterial communities that are different from their environment, change throughout their development, and shape evolutionary and ecological processes. The bathymodiolin (Mytilidae) mussel Gigantidas childressi lives at deep-sea methane seeps and relies on methanotrophic endosymbionts for its nutrition. Its larval life, however, is spent feeding in the water column. Upon metamorphosis at a suitable seep habitat, methanotrophic bacteria rapidly colonize gill cells and the juvenile mussel switches to symbiont-derived energy. To determine if the microbiome of the G. childressi changes during these transitions, the V3/V4 region of the 16S rRNA gene was sequenced to census …

Characterization Of Phenotypic Traits Related To Loss-Of-Function And Ectopic Expression Of Bhlh093 And Bhlh061 In Arabidopsis Thaliana, Leila Belhadjali

WWU Graduate School Collection

bHLH093 and bHLH061 are members of sub-group IIIb of basic helix-loop-helix (bHLH) Arabidopsis thaliana transcription factors. Although bHLH proteins are the second largest transcription factor family in Arabidopsis, only a small proportion of them have been functionally characterized. Here, we investigated the phenotypic impact of bHLH061 and bHLH093 ectopic overexpression and loss-of-function to confirm previously published results and provide new insight into their role in development. bHLH093 and bHLH061 are homologs of two stomatal development genes, SCREAM1/ICE1 and SCREAM2 and have been shown to dimerize with two master regulators of stomata development, FAMA and MUTE. While no evidence was found …

Predator-Induced Hatching Plasticity Of Northeastern Pacific Coast Nudibranchs, Geoffrey Masato Mayhew

WWU Graduate School Collection

Many organisms have complex life cycles that include ontogenetic niche shifts, or changes to morphology, physiology, diet, predators, and habitat. Natural selection favors individuals that choose the optimal time to undergo ontogenetic niche shifts that avoids unnecessary losses to fitness, and niche shift timing is therefore considered a plastic trait. Hatching is a common niche shift within animals, and modifications to hatch timing can mediate the costs and benefits of hatching sooner or later, depending on varying predation risk, resource availability, or habitat conditions. Predator-induced hatching plasticity in particular is well-documented within amphibians as well as other terrestrial vertebrates and …

Biodegradable Plastic Degradation Products Alter Germination And Growth Of Aspergillus, Taylor Cofer

WWU Graduate School Collection

Although much work has been focused on micro and nano-plastics in soils, the bioactivity of common plastic additives (plasticizers) and monomers have been overlooked. One source of plastic pollution in agricultural soils is breakdown products from plastic soil covers called mulches. The plastics industry is attempting to make biodegradable plastic mulch (BPM) that have reduced environmental impacts and removal costs compared with those typically associated with conventional plastic mulches. Two common polymers added to BPMs are thermoplastic starch (TPS) and poly(butylene-adipate-co-terephthalate (PBAT). In this study, the effects of components that can leach from TPS and PBAT were investigated to determine …

Holistic Approaches For Invasive Species Management: Exploring Biotic Resistance Of European Green Crab (Carcinus Maenas) Via River Otter (Lontra Canadensis) Diet, Bobbie Buzzell

WWU Graduate School Collection

Establishment of the European green crab (Carcinus maenas) on the west coast United States has led to concerns regarding loss of eelgrass beds and influence on marine communities. To begin examining whether predators can potentially buffer green crab expansion, I studied river otter (Lontra canadensis) diet from scat remains and estimated green crab abundance from removal trapping efforts. River otter scats on the Wa’atch and Tsoo-Yess rivers, Washington, USA, were collected during August-September 2018 and April-September 2019. Hard remains of prey were reported as percent frequency of occurrence, and green crab prey were compared to monthly …

Individual Variability In Foraging Success Of Harbor Seals (Phoca Vitulina) Preying On Pacific Salmon (Oncorhynchus Spp.) Informs Predator Management, Grace Freeman

WWU Graduate School Collection

The complexities of trophic dynamics complicate the management of predator populations. In some cases, targeted culling campaigns are meant to control predator populations. In these campaigns, predators are considered ‘rogue individuals’ based on visitation rates to a site. This definition carries the underlying assumption that all predators impact prey equally, however, individual variability in foraging success may compromise such an assumption. Thus, to test the hypothesis that foraging success varies among individual predators, I studied harbor seals preying on adult Pacific Salmon during the 2014-2019 fall salmon runs. I analyzed individual harbor seal visitation rate and foraging success based on …

Mixotrophy By Phytoflagellates In The Northern Gulf Of Alaska: Impacts Of Physico-Chemical Characteristics And Prey Concentration On Feeding By Photosynthetic Nano- And Dinoflagellates, Hana Busse

WWU Graduate School Collection

Long term monitoring in the Northern Gulf of Alaska (NGA) has shown that the high productivity of the region is closely coupled to lower trophic level food web dynamics. From previous observations of the NGA, we know that many nano- and dinoflagellates that compose this food web are mixotrophic, and therefore capable of both phagotrophy and phototrophy in a single cell. This behavior is believed to stabilize food webs by providing multiple pathways to energy and nutrients and may play an important role in the NGA, where environmental conditions are harsh and highly variable. To better understand the role of …

Mapping Genetic Variants Associated With Dynamic Protein Abundance In Haploid Yeast, Tanner Thuet-Davenport

WWU Graduate School Collection

As organisms respond to changes in their environment genetic variation between individuals can directly affect organismal trait phenotypes by altering gene expression. Historically, studies have focused on the effect of genetic variation on mRNA synthesis (transcription) and decay rates. Relatively few studies have probed the relationship between DNA variants and protein-specific regulation of individual genes, despite the plethora of evidence that RNA levels are often poor proxies for protein levels. No study to date has mapped genetic variation associated with dynamic protein levels. In this study we investigated the location and identity of genetic variants acting on protein expression dynamics …

Hybridization Between An Invasive Fruit Fly And A Variably Plastic Native Sibling Species, Weston Staubus

WWU Graduate School Collection

Introgressive hybridization can play an important role in the evolution of species ranges by introducing adaptive variation to populations at the margins. The apple maggot (Rhagoletis pomonella) is an introduced tephritid fly that has become abundant in the moist western counties of Washington State but remains scarce in the relatively arid central and eastern counties. In contrast, the snowberry maggot (R. zephyria), a native congener, is abundant in counties across the state. The difference in the distributions of the two species has been attributed to variation in their desiccation resistance because snowberry maggots, particularly those from …

Recovery Of The Sea Star Heliaster Kubiniji From A Mass Mortality Event, And Additional Dynamics Of Intertidal Invertebrates Within The Gulf Of California, Carter Urnes

WWU Graduate School Collection

In 1978 populations of a charismatic and abundant intertidal sea star Heliaster kubiniji (Xantus) declined throughout the Gulf of California. Two years after this mass-mortality event, researchers found very low densities of H. kubiniji at many sites throughout the region and concluded that the species had not recovered. To my knowledge H. kubiniji densities in the Gulf of California have not been formally surveyed since the 1980 mass-mortality event. Although intertidal sampling has sporadically occurred within the region, many questions regarding invertebrate populations remain unanswered. To better understand and predict the recovery of echinoderms from mass-mortality events, I returned to …

Investigating The Effects Of Climate Co-Stressors On Surf Smelt Energy Demands, Megan Russell

WWU Graduate School Collection

Surf smelt (Hypomesus pretiosus) are ecologically and economically important to the Pacific Northwest. They play a critical role in the food web and support numerous commercially important species and are an economically important baitfish. Surf smelt interact closely with the nearshore environment, utilizing approximately 10% of Puget Sound coastlines for spawning throughout the year. Surf smelt spawn at high tide and adhere fertilized eggs to beach sediment, causing their embryos to be exposed to air and seawater throughout embryonic development. Because of this unique life history, surf smelt may be susceptible to anthropogenic stressors including coastal development and …

The Impacts Of Sex-Specific Diets Of A Marine Predator On Ecosystem Models, Jonathan Blubaugh

WWU Graduate School Collection

Ecosystem modeling is an increasingly popular method to understand how organisms within ecosystems interact, relying on robust data incorporating important inter- and intraspecies interactions to predict ecosystem changes. However, no study has included sex-specific intrapopulation variation in an ecosystem model. In the well-studied Salish Sea, harbor seals (Phoca vitulina) are an important marine mammal that have significant sex-specific diet variability, which I hypothesized would have indirect effects on other functional groups in the region. Male harbor seals consume a higher diet proportion of salmon, while female harbor seals consume a higher proportion of herring and small demersal fish. …