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Item Mud volcano imaging using ambient seismic noise(2021) Goerzen, ChetMud volcanoes are a relatively little known geological phenomenon. They are characterized by the extrusion of mud at the earth’s surface. Mud volcanoes represent a serious risk to human life and property, and may also play an important role in the natural greenhouse gas cycle. The Waimata Valley region of New Zealand has been known to have several episodes of mud volcanism. A dense array of short-period geophones was deployed in order to study the subsurface structure of this area. Mud volcano eruptions have occurred many times in the past before the array of geophones was deployed. There was also a mud volcano eruption that occurred several months after the geophone array was decommissioned. Ambient noise tomography was employed in order to study the subsurface structure of the mud volcano by creating a 3-D model of shear wave velocity within the area of mud volcanism. Low-velocity zones were observed in regions underlying the known surface expressions of mud volcanism. An area of mud volcanism that had been dormant since 1930 was observed to correspond to a low-velocity region, suggesting that the source of the mud volcano persists long after an eruption. A low-velocity zone was also observed in the area that later hosted a mud volcano eruption. This suggests that areas of potential mud volcanism may be identified by low-velocity zones revealed by ambient noise tomography. Supervisors: Honn Kao and Lucinda LeonardItem Using geophysical methods to constrain the Quaternary activity of the eastern San Juan fault(2026) Irwin, DannyUpper plate faults of southern Vancouver Island have hosted Quaternary earthquakes, posing a significant risk to the densely populated regions of Greater Victoria, Vancouver, and Seattle. The San Juan fault lies adjacent to several faults that have been proven active in the Quaternary, yet its activity remains uncertain due to lack of study. I use a recently available wealth of lidar data to carefully map the eastern part of the fault, looking for intersects between fault lineaments and glacial morphological features. I find a site that is easily accessed by vehicle, where a suspected fault scarp is clearly visible in the lidar data, situated in glacial deposits. Either this scarp formed before the till was deposited, or the scarp formed since the deposition, and is due to either dip-slip and/or strike-slip motion. I perform electrical resistivity tomography, relative gravity, and total magnetic field surveys across the scarp at this location to test these hypotheses, with the resistivity profile showing the most decisive results. Fault structures are observed, and disruptions appear in the uppermost layer, with little visible vertical offset in the till bases, consistent with fault rupture in the Quaternary, with the motion being mostly strike-slip. These findings, combined with similar findings from previous studies further west on the San Juan fault, make a compelling case for further work on the fault, and this location, with its ease of vehicular access, presents the ideal setting. Supervisors: Lucinda Leonard and Edwin NissenItem Anatomical and ultrastructural characterization of the frog accessory olfactory bulb and vomeronasal nerve(University of Victoria, 2026) Merx, XanderThe accessory olfactory bulb (AOB) serves as the central relay for vomeronasal chemosensory information and has been implicated in activity-dependent synaptic plasticity in frogs. Activity-dependent enhancement (ADE), observed at the vomeronasal nerve (VNN)–mitral cell synapse, has been described in Rana pipiens and hypothesized to involve neuropeptide co-release from dense-core vesicle (DCV)-containing afferent terminals. Bimodal compound action potential recordings from the Lithobates catesbeiana VNN suggest the presence of two morphologically distinct axon populations. The present study employed light microscopy, transmission electron microscopy (TEM), and horseradish peroxidase (HRP) anterograde tracing to characterize the anatomy and ultrastructure of the AOB and VNN in adult L. catesbeiana. Light microscopy revealed a laminated AOB with glomerular and mitral cell layers; a notably sparse periglomerular cell population was identified, consistent with the frog AOB being less elaborated than its mammalian counterpart. TEM of the glomerular neuropil identified likely dendrodendritic synapses and gap junctions, features documented in the mammalian olfactory bulb but not previously reported in the frog AOB. Large vesicular profiles with electron-dense cores were observed in HRP-DAB labeled VNN afferent terminals; however, the evidence is insufficient to confirm the presence of dense-core vesicles, and these observations do not provide anatomical support for the neuropeptide co-release hypothesis. Quantitative axon diameter analysis identified two morphologically distinct fascicle types: Type A fascicles with a unimodal small-axon distribution and Type B fascicles with a bimodal distribution with a sparse large-profile subpopulation, consistent with the bimodal CAP profile. These structural observations support ongoing functional investigations and warrant further study using biochemical and volumetric imaging approaches. Supervisor: Dr. Kerry DelaneyItem Variation in Pseudotsuga menziesii foliar fungal endophyte community composition over a growing season(University of Victoria, 2026) McCarroll, CallahPlants host a diverse array of micro-organisms referred to as endophytes, which reside primarily in the interstitial spaces between plant cells. Endophytes often exist in complex communities composed of multiple species from multiple kingdoms, although fungi are the most common colonizers of plant tissues. These micro-organisms interact with each other and with the host, sometimes resulting in altered phenotypes for the host plant which can be beneficial or detrimental. Determining what drives the structure of these community assemblages is a key prerequisite for understanding the overall nature of microbial ecology. Douglas-fir trees (Pseudotsuga menziesii) are a keystone species threatened by disease, climate change, and human development, and like all plants, they harbour a diverse suite of fungal endophytes. In this research, the temporal dynamics of Douglas-fir foliar fungal endophyte communities was systematically characterized over an entire growing season. This was done by collecting Douglas-fir needles from 16 trees in a single location six different times over a calendar year. High-throughput sequencing-based metabarcoding was employed to amplify fungal ITS1 sequences for identification of fungal endophyte community members within Douglas-fir leaf tissue at different times of the year. Using both Alpha and Beta diversity measures, this research was able to show significant community dissimilarity between sampling months. This research also described a dominant unknown endophyte within the order of Mycosphaerellales appearing to have a negative relationship with Nothophaeocryptopus gaeumannii, a well studied Douglas-fir endophyte and causal agent of Swiss needle cast disease. This is the first seasonal description of fungal endophytes within Douglas-fir needles using meta-barcoding analyses. Supervisor: Dr. Jürgen EhltingItem Non-visual opsin expression in the optic tectum of starry flounder (Platichthys stellatus)(University of Victoria, 2026) Aveyard, LaurelNon-visual opsins are light sensing proteins that are not associated with the typical image forming process and can be found not only in the retina, but across a wide variety of tissues such as brain and skin. Their expression in the brain specifically has been documented in several species, but the question remains as to whether these proteins are contributing to light sensitivity of the brain itself. The starry flounder (Platichthys stellatus) is a species of flatfish with several ecological and anatomical characteristics that allow for an indirect method of investigating the potential of brain light sensitivity. Because of their asymmetrical anatomy, their brains are located with one hemisphere pointing upwards and receiving more light stimulus than the other. They are found as both left sided and right sided individuals in the wild, meaning investigation of light sensitivity related to the upwards facing hemisphere in a given individual is possible. This study investigated expression of the specific non-visual opsin melanopsin in the optic tectum of the brain, which is the structure responsible for integration of visual stimuli. This was done using an immunohistochemical staining technique with antibodies designed to bind mammalian-like melanopsins. This provided a qualitative analysis of the levels of expression and how they differed between the hemispheres. There was no notable qualitative difference found between hemispheres in terms of expression, however there appeared to be pan-neuronal labelling throughout both hemispheres of the optic tectum. Further research is required to identify levels of protein expression, however this is an indication of melanopsin presence in the starry flounder brain and is a first step in understanding how these proteins may function in this asymmetric species. Supervisor: Dr. John TaylorItem Characterization of the sex associated region in the sablefish genome(University of Victoria, 2026) Carlow-Ujiie, TasminThe locus that determines sex in sablefish (Anoplopoma fimbria) and a putative master sexdetermining gene, gsdf, were mapped to chromosome 14 in 2013. In 2021, the role of gsdf was confirmed and the allele responsible for sex was characterized to be a 936 transposable element insertion upstream of gsdf that upregulates expression in developing testis and determines maleness via a male heterogametic (XX/XY) system. According to classical theory of sex chromosome evolution, a sex-determining mutation creating a master sex-determining (MSD) gene is followed by recombination suppression spreading from that locus and eventual chromosome degradation and differentiation which ultimately produces heteromorphic sex chromosomes. In sablefish, it was not clear whether X and Y versions of chromosome 14 differed beyond the gsdf insertion. In this study, we used genome wide association studies (GWAS) and linkage disequilibrium (LD) analyses to define boundaries of the sex-associated region (SAR). We found that loci with genotype frequencies that differed between males and females were distributed across a large region of chromosome 14 (38,000 bp). Genes within this block include LOCI129102360, nup54, LOCI129102793, and gsdf. A weaker male-specific block of LD beyond the SAR included aff1. Alleles of nup54, LOCI129102793, and aff1 on the gsdfY-bearing (Y) chromosome differed nonsynonymously from X-linked counterparts. These genes therefore appear to be ‘founder loci’ of an emerging sex-determining region. Moving forward, characterization of the SAR at this stage of sex chromosome evolution will explicate the rate and progression of the sex-determination system in sablefish. Supervisor: Dr. John S. TaylorItem Using ocean gliders to understand the physical oceanography of Fitz Hugh Sound(2026) Williamson, MartinAutonomous glider transects from Queen Charlotte Sound (QCS) into Fitz Hugh Sound (FHS) provide high resolution cross-sections of temperature, salinity, density, and oxygen that reveal the dynamics of deep-water renewal and vertical mixing in a deep-silled fjord on the central coast of British Columbia. Glider transects collected between March 2024 and August 2025 were analyzed alongside Hakai CTD surveys to document the timing, structure, and modification of renewal flows. Renewal primarily occurs as a summertime process, with dense QCS shelf water flowing over the Hakai Passage (HP) sill and flushing the FHS deep basin, with an upper layer of FHS water leaving through HP as a return flow. Renewal appears to occur over the HP sill as opposed to the wider southern sill. A temperature - salinity parameter space comparison suggests that weaker winter renewal can also occur, bringing higher oxygen water into the deep basin. Simple two-layer hydraulic control estimates give upper bound flow velocities of 0.6-0.7 ms−1 and volumetric fluxes of 3.6-4.2 × 104 m3 s−1, implying a characteristic deep basin flushing timescale of roughly 15-19 days during renewal conditions. Vertical diffusivity estimates based on conservative tracers yield values on the order of 10−3 m2 s−1, consistent with previous studies in similar British Columbia fjords and waterways. Although source waters on the shelf occasionally reached hypoxic concentrations during the study period, mixing over the sill and along the renewal flow path increased oxygen levels, preventing hypoxia in the FHS deep basin. These results highlight the role of sill mixing in buffering deep fjord basins from hypoxic shelf source water, but also suggest that future declines in oxygen on the QCS shelf could overcome this protection if water of lesser density becomes hypoxic. Supervisor: Jody KlymakItem Characterizing the expression of cholinergic neurons within the mouse dorsal subiculum(University of Victoria, 2026) Girard, DanielAcetylcholine (ACh) is a neurotransmitter used for a variety of functions including muscle contraction and neurotransmission between neurons in the brain. Choline acetyltransferase (ChAT) is an enzyme that synthesizes ACh. Using a genetically modified mouse line (ChATcre::ChR2-YFP) allows us to visualize ChAT expression in brain regions due to the co-expression of yellow fluorescent protein (YFP). The dorsal subiculum expressed YFP fluorescence in adult mice, suggesting that this brain region is cholinergic despite previous research claiming otherwise. Using confocal microscopy, this study characterized YFP expression within the dorsal subiculum coupled with ChAT immunolabelling to examine whether this brain region contains cholinergic neurons. Brain sections from six ChATcre::ChR2-YFP mice between 59-95 days old of both sexes were examined. To validate correct YFP expression and ChAT labelling in other brain regions known to contain cholinergic neurons, we immunolabelled and quantified ChAT and YFP positive neurons in the primary visual cortex, the striatum, and medial habenula. We confirmed high YFP and ChAT co-expression from these brain regions. In the dorsal subiculum, we imaged YFP neurons, ChAT immunolabelled neurons, and NeuroTrace labelled neurons. Based on our results, the dorsal subiculum contained very few ChAT positive cholinergic neurons and is therefore non-cholinergic. Despite this, the sparse ChAT-labelling colocalized with YFP expression while the majority of YFP labelled cells did not co-express ChAT immunolabelling, suggesting that ChAT may have been present in the dorsal subiculum prior to adulthood. Future work should examine the subiculum during development to see if ChAT-labelling fully colocalizes with YFP expression. Supervisor: Dr. Raad NashmiItem Melanopsin (opn4) immunolabelling in the zebrafish (Danio rerio) brain(University of Victoria, 2026) Ma, Isabel G.Light is an important signal for vertebrates, not only for image-forming vision, but for non-visual roles including development and physiological responses. Vertebrates detect light using light-sensitive proteins called opsins that are paired with a chromophore. Non-visual opsins are found in a diversity of tissues in vertebrates for both mammals, with the fewest opsins, and ray-finned fishes, with the largest opsin repertoires. Many studies have characterized non-visual opsin mRNA in fish brains, especially in the model zebrafish (Danio rerio), and a few studies have delved into the roles of non-visual opsins. Of the non-visual opsins, melanopsin (opn4) is the most well-studied. It has been observed in intrinsically photosensitive retinal ganglion cells (ipRGCs), which have various roles, including in the circadian rhythm, pupillary light reflex, and mood. Melanopsin mRNA has been characterized in the zebrafish brain, and melanopsin proteins have been observed in sablefish (Anoplopoma fimbria) brains. However, until now, no studies have investigated the expression of melanopsin proteins in zebrafish brains. This study uses immunohistochemistry to show melanopsin proteins in the adult zebrafish brain. Melanopsin occurs in two layers of the optic tectum (the superficial white and grey zone and central zone), the torus longitudinalis, large cells in the paraventricular organ, the torus lateralis, the inferior lobe, and the hypothalamus. Presence of melanopsin proteins in the zebrafish brain is consistent with the hypothesis that the brain is intrinsically light sensitive, and localizing the proteins will help direct future studies designed to test the light-sensitivity hypothesis. Supervisor: Dr. John S. TaylorItem Modelling bonus seismic wave arrivals recorded on SchoolShake seismographs from the March 2025 Orcas Island earthquake(2026) Reed, SedonaIn the seismograms recorded at SchoolShake network seismographs across Greater Victoria, BC during the M4.5 Orcas Island earthquake on March 3rd, 2025, a bonus wave arrival was identified between the P and S arrivals at stations within an azimuthal range of 219-256° around the epicenter. Such arrivals had not been previously documented. The focus of this study was to determine the origin of the bonus seismic wave arrivals using seismic ray path and travel time modelling for increasing levels of model complexity. Initial modelling using the 1-D ObsPy.TauPy software successfully reproduced direct P and S wave arrivals but was insufficient to model the bonus phase arrivals. Subsequent 2-D modelling using Pykonal was implemented to better account for the subsurface structure, which includes dipping boundaries such as the top of the subducting Juan de Fuca plate. This modelling demonstrated that a reflection of seismic energy off the Juan de Fuca slab produced arrivals too late to match the bonus arrivals, therefore ruling out this boundary as their origin. Modelling reflections off a shallower boundary, consistent with the highly seismically reflective E-layer, produced arrival times consistent with the actual bonus phase arrivals. Residuals between the observed and modelled arrival times were minimized to lie within ±0.8 seconds across the analyzed stations, providing evidence that the bonus arrivals are consistent with P wave energy reflection off the top of the E-layer. These findings demonstrate the need for more spatially complex subsurface models, such as the 2-D Pykonal model and ideally a 3-D model, to model seismic wave travel in the presence of dipping subsurface boundaries. The bonus phase arrivals may contribute to longer and more intense shaking, which highlights the importance of understanding seismic wave travel to improve local hazard assessment and risk mitigation in Greater Victoria. Supervisors: Camille Brillon and Lucinda LeonardItem The surprising power of fragmentation: How fuel discontinuity limits wildfire spread(2025) Bitz, QuinnWildfire growth depends not only on the quantity of fuel but also on its continuity across the landscape (Keane et al., 2001; Pfeiffer et al., 2013). Fine-scale discontinuities such as roads, rivers, or rocky outcrops can halt fire progression, yet these features are often overlooked in large-scale fire models that treat fuels as homogeneous (Archibald et al., 2009; Bowman et al., 2020). This project investigates how fuel fragmentation at 30 m resolution constrains burned area in realistic landscapes. Using the ELMFIRE fire spread model (Lautenberger, 2013) with LANDFIRE LF 2023 inputs (LANDFIRE, n.d.), I simulated nearly 8,000 ignition scenarios across five 60 × 60 km domains in the western United States. Burned and burnable area fractions were calculated for each 5 × 5 km tile (sub-domain) to quantify how fuel discontinuities interact with wind and landscape structure. Results show that burned area increased exponentially across the full range of fuel continuity, forming an upper-limit relationship between burnable and burned area fractions. Fragmented landscapes rarely supported large-scale spread, defined here as cases where more than half of the burnable area was consumed. Wind speed had little effect under low connectivity, but in continuous fuels, stronger winds substantially amplified fire size. Other potential controls, including slope and vegetation structure, were weakly related to burned area, reinforcing fragmentation as the dominant limiting factor. These findings demonstrate that fuel continuity imposes natural limits on wildfire growth, even under favourable weather. Incorporating such constraints into continental- and global-scale fire models could improve their ability to capture realistic spread dynamics in heterogeneous landscapes. Supervisors: Jed O. Kaplan and Colin GoldblattItem Describing the Alpine-Treeline Ecotone on Mount Arrowsmith and its response to climate change over 20 years(University of Victoria, 2026) Grogan, ErinThe Alpine-Treeline Ecotone (ATE) is a temperature-sensitive transitional plant community, which has had various responses to climate change across the world. On Vancouver Island, it is predicted that the extent of alpine-tundra plant communities will be reduced and replaced with mountain hemlock forests as warming increases the ranges of lower elevation species. This study aims to describe the plant community composition within the ATE at Mount Arrowsmith, on Vancouver Island, and investigate directional changes in community composition over the last 20 years, using the GLORIA protocol. At Mt. Arrowsmith, the ATE is dominated by rock cover with low vascular plant cover and most closely resembles Rhizocarpon geographicum plant communities found elsewhere in the southern Coast Mountains. Microsites result in two vegetation associations being present: Penstemon – Juniperus on xeric sites and Phyllodoce – Abies on more developed soils. No significant changes in plant community composition over the last 20 years were detected, with vascular plant cover remaining stable and rock remaining the dominant cover. Species richness also remained stable over the study period; however, turnover occurred with species gained and lost with each survey and one new invasive species in 2025. The plant community within the ATE at Mt. Arrowsmith has not exhibited directional change over the last 20 years. Continued monitoring will be needed to assess plant community responses to ongoing climate change. Supervisor: Dr. Terri Lacourse Co:Supervisor: Dr. Noémie Boulanger-LapointeItem Comparing cold and drought tolerance in Sequoia sempervirens and Sequoiadendron giganteum at The Butchart Gardens and University of Victoria(Univserity of Victoria, 2026) Wardell, StephanieDrought and cold are important limiting factors for plant growth that can impact health and visual appeal. For show gardens that often plant non-native species, it is important to understand a species’ tolerance of the conditions in a foreign range. The Butchart Gardens (TBG) in Victoria, B.C. is a National Historic Site of Canada that features many prominent, nonnative species. The two Californian Sequoia sempervirens (D. Don) Endl. planted on the property are important focal points within the Gardens, but this species is known to have poor cold and drought tolerance. Comparatively, the Sequoiadendron giganteum (Lindl.) Buchh. is a related Californian species that is commonly planted as an ornamental tree. Due to its cold and dry native range, the S. giganteum is considered to have greater drought and cold tolerance. Drought and cold tolerance of individuals of both species at TBG and the University of Victoria (UVic) were compared from late summer to early winter in the context of irrigation regimes to understand what differences in care may improve stress tolerance and growth of these trees. Drought tolerance was assessed biweekly from July to November with a Scholander pressure chamber using shoot samples of S. sempervirens and S. giganteum individuals at UVic and TBG. The cold tolerance of shoot samples from the same individuals were assessed from September to January using a freeze-induced electrolyte leakage test. The S. giganteum individuals developed cold tolerance more rapidly than S. sempervirens in autumn, likely a result of the S. giganteum adaptation to colder native ranges. The S. giganteum showed greater variability in drought stress through the sample period, but responded rapidly to changing water availability, unlike the S. sempervirens. The S. sempervirens individuals at UVic that received high amounts of irrigation were less drought stressed, indicating a reliance on irrigation to minimize drought stress and that individuals at TBG would benefit from increased irrigation. The sampled S. giganteum individuals were more drought and cold tolerant than the S. sempervirens, indicating that S. giganteum is more tolerant of the climate and weather in Victoria, B.C. Supervisor: Dr. Barbara Hawkins Honours Advisor: Dr. Terri LacourseItem A trait-based assessment of the functional diversity of marine Cetacea in the Canadian Offshore Pacific Bioregion(2025) Tuck, MatthewThe identification of biodiversity hotspots is a critical step in the protection and conservation of wildlife, and the ecosystems they depend upon. Recently, the identification of numerous highly diverse benthic seafloor and seamount habitats in the Canadian Offshore Pacific Bioregion (OPB) has prompted the establishment of large marine protected areas (MPAs) which target the protection of these sensitive benthic habitats. This region has high productivity due to eddy associated upwelling of nutrients, and contains numerous unique environments, including the continental slope, cold water seamounts, hydrothermal vents, and the open ocean. Elevated productivity supports a number of Cetacea species, which take advantage of seasonal windows of productivity. Cetaceans provide ecological functions related to nutrient transfer (e.g., the whale pump), food web processes (e.g, suppression of lower trophic levels), and the creation of unique seafloor habitats (i.e., whale falls). Despite the functional importance of these species, present conservation measures in the OPB and its associated MPAs do not legislate protections targeting the surface waters Cetacea species depend on. Here, I assess whether the OPB hosts a functionally diverse subset of the global marine Cetacea species pool through comparative analyses based on the global functional space of Cetacea spp., using seven traits related to species roles in food web processes and nutrient cycling. I also identify unique features of the species found in the OPB by comparing their trait distribution to the global Cetacea species pool. The OPB hosts 28% of the known marine Cetacea species but encompasses 70% of the global marine cetacean functional space. The functional dispersion and functional redundancy of the OPB mirrors values obtained from randomly subsampling the global species pool, indicating that the region is a representative sample of functional diversity present in the global species pool. Species using the OPB are distinguished by increased body sizes, likely due to the increased richness of large-bodied, baleen feeding Mysticeti species. The functional roles of large bodied species are fundamental for ecosystem health and stability, but are being eroded around the world as human activities continue to down-size the populations of the largest megafauna on Earth. Thus, the OPB is critical for protecting a high proportion of the global cetacean functional diversity, and the ecological roles of large cetaceans.Item The contribution of NMDA receptors to contrast coding in ON retinal ganglion cells of Mus musculus(2024) Westby, TamateaThe retina encodes contrast (the difference in light intensity between an object and its background) using a complex network of neurons that end in ganglion cells (GCs) which transmit visual signals to the brain. GCs express both AMPA and NMDA type glutamate receptors, with NMDA receptors (NMDARs) having high glutamate affinity and variable localization patterns. Previous studies in guinea pig retinas found no NMDAR contribution to contrast coding in ON-∝ GCs but found that these receptors were expressed in mice ON-GCs. My study investigated the contribution of NMDARs to contrast coding in mouse ON-GCs. I used whole-cell voltage clamp electrophysiology in ON-GCs from Mus musculus retinas and recorded light-evoked responses to spots of varying contrast. I then determined receptor-specific contributions to the recorded responses using a deconvolution technique which avoided the potential confounding effects of using pharmacology. I first investigated whether NMDARs contribute to low contrast responses and then examined how their conductance changes with increasing contrast. The results revealed a significant NMDAR component to low contrast responses that scaled with increasing contrast. These findings provide new insight into contrast coding mechanisms in the retina, suggesting that NMDARs play a key role in shaping ON-GC responses.Item Quantitative analysis of 3D heterochromatin structures within and between neuronal cell types(2025) Smith, RoryHeterochromatin organization within neuronal nuclei plays a critical role in maintaining genomic stability and regulating gene expression, yet its 3D morphological variability between neuron types remains poorly understood. Using confocal microscopy, we quantitatively analyzed heterochromatin 3D structures within neuronal nuclei. Existing methods in the literature were re-created to measure the distribution of nuclear intensity into predefined classes, as well as basic morphological features of the foci (volume, eccentricity, etc.). However, these morphological descriptors impose rigid, preconceived geometric assumptions that do not consider 3D spatial positioning. We attempt to address these limitations with a novel computational method that directly assays both spatial and morphological "similarity" of heterochromatin formations in nuclei. This approach was applied to a range of neuron types to assess variation within and between groups. Our results demonstrate significant differences between spatial heterochromatin foci positioning between neural types. If coupled with immunohistochemistry and increased replicates, we conclude with a demonstration of how this analysis could be applied to effectively study single-genotype differences in heterochromatin formation. This methodology offers a generalizable framework for studying morphological changes in other genotypes and nuclear protein disorders, which is of interest to various neurodevelopmental disorders.Item Characterizing the impact of oocyte nutrient-sensitive genes on reproductive aging in Caenorhabditis elegans(2025) Rossander, EmmaReproductive aging is the gradual decline in reproductive function over time, encompassing reductions in fertility, hormonal changes, and diminished germ cell quality. This process is highly sensitive to nutrient conditions, as sufficient energy availability is essential for maintaining reproductive function. However, nutrient surplus may accelerate aging and impair fertility. Prior studies have demonstrated that Caenorhabditis elegans (C. elegans) exposed to a high-glucose diet exhibit reduced reproductive capacity and compromised oocyte quality. Poor oocyte quality is a well-documented contributor to reproductive dysfunction in both C. elegans and humans, underscoring the importance of understanding the molecular mechanisms that influence reproductive health under obesogenic diets. Genes whose transcription is regulated in a nutrient-sensitive manner play a critical role in mediating the relationship between diet and reproductive function. This study aimed to determine the impact of two such genes, icmt-1 and psme-4, on the reproductive capacity of C. elegans by using RNAi-mediated knockdown. C. elegans were exposed to lifelong RNAi and subject to elevated glucose exposure (20 mM glucose) starting at the fourth larval stage to coincide with establishment of the reproductive system. To assess the reproductive capacity in aging worms, C. elegans were mated on day five (D5) of adulthood, and their reproductive success was evaluated based on progeny production. Additionally, D5 oocytes were imaged using DIC imaging to assess morphological changes and overall oocyte quality in response to gene knockdown and high-glucose exposure. This study found that the RNAi knockdown of icmt-1 significantly reduced reproductive success in aging C. elegans, potentially due to systemic effects rather than direct impact on oocyte quality. Since icmt-1 regulates Ras protien localization and apoptotic pathways, its knockdown may cause widespread cellular stress and metabolic disruptions that impair reproduction. Conversely, psme-4 knockdown significantly improved age-related reproductive success and oocyte quality under glucose-enriched conditions, suggesting that reducing proteasomal activity may mitigate glucose-induced reproductive decline. psme-4 knockdown did not significantly affect reproductive capacity under normal dietary conditions, indicating that its glucose-induced upregulation may play a role in the reproductive defects observed under high-glucose conditions. These findings suggest that icmt-1 and psme-4 influence reproductive responses to dietary glucose, offering insight into the genetic basis of diet-induced infertility.Item Analysis of synaptic plasticity events concerning the endocannabinoid system in the young adolescent (YA) rat media perforant pathway (MPP) following repetitive mild traumatic brain injury (r-mTBI)(2025) Zejnulahovic, EmirTraumatic brain injury (TBI) is a widespread health issue, with mild TBIs (mTBI) making up to 85% of cases, often underdiagnosed due to subtle symptoms. Young adolescents are most at risk for repetitive mTBI (r-mTBI), which compounds mTBI symptoms and outcomes. These injuries can impair synaptic plasticity, including short-term potentiation (STP) and long-term potentiation (LTP), both crucial for cognition. Acute neuronal damage and chronic apoptosis underlie these deficits, especially in the dentate gyrus (DG) and its medial/lateral perforant pathways (MPP/LPP) substructures, whose electrical inputs are essential for adult neurogenesis. Cannabinoid one receptors (CB1Rs) and Transient Receptor Vanilloid Protein 1 (TRPV1), part of the endocannabinoid system (EC), regulate synaptic plasticity in MPP/LPP due to the high concentrations each receptor has in the DG. Altered EC signaling in mTBI models contributes to excitotoxicity. Pharmacological tools for targeting CB1Rs (AM251) and TRPV1 (AMG9810) reveal the receptor’s effects indirectly before and after r-mTBI. 53 Sprague Dawley rats were used for recordings, with ninety-nine slices used. Animals were split across six groups (Sham/r-mTBI controls, plus corresponding drug groups). Sham/r-mTBI controls only showed differences in LTP induction, with mechanistic properties of the synapse appearing unchanged via paired pulse and short-term potentiation (STP) recordings. Both AMG9180 and AM251 restored LTP deficits seen between Sham/r-mTBI controls, while TRPV1 also significantly enhanced STP levels, and removed paired-pulse facilitation effects seen in Shams. This suggests that both receptors can be pharmacologically manipulated to aid in synaptic plasticity deficits following r-mTBI, as well as suggesting that both receptors are downregulated following r-mTBI.Item Investigating the environmental and anthropogenic drivers of temperate reef grazers and developing a grazer-based metric for assessing reef health(2025) Jones, Alec E.Grazers structure ecosystems by consuming primary producers. Recently, human-induced predator loss has caused destructive overgrazing of foundational species by grazers. Kelp forests are one critical ecosystem that has been affected, where red sea urchin (Mesocentrotus franciscanus) grazers have overconsumed many areas, resulting in barren habitats. Importantly, not all grazers in these ecosystems remove the kelp canopy; species such as the red turban snail (Pomaulax gibberosus) merely graze on biofilms or remove small patches leaving the kelp blades intact. Given the disruptions (e.g., predator loss) to normal grazer controls, identifying key factors regulating grazer populations is crucial to inform conservation action. We investigated potential environmental and recreational fishing drivers of red sea urchin and red turban snail density on rocky reefs. We predicted that temperature and wave exposure would negatively affect grazer density, and that grazer density would be lower on loose seafloor. We also predicted lower urchin density and higher snail density in protected areas, where limited fishing promotes higher trophic levels and larger-bodied predators. We found a strong negative relationship between turban snail density and wave exposure, suggesting turban snails may be impacted by increases in wave energies. Conversely, urchin density was not significantly associated with any of the environmental variables tested, supporting that this species tolerates a wide range of environmental conditions and can maintain high densities over diverse regions without management intervention. Indeed, we found that protected areas with reduced fishing pressure returned significantly higher snail-to-urchin ratios, translating into healthier ecosystems and intact kelp forest communities. Reduced fishing pressure likely contributed to more complete predator communities in protected areas, which can improve urchin control, leading to increased macroalgal growth and snail densities. Our results support the role of protection from fishing as a key management strategy that can regulate damaging urchin populations and promote healthier reef communities.Item Ontogenetic shifts in the diet of commander squid (Berryteuthis magister) in the Salish Sea revealed through stomach content and stable isotope analyses(2025) Hummelbrunner, EliseCephalopods play crucial roles in marine ecosystems, yet their dietary habits remain underexplored in many regions. This study examines ontogenetic shifts in the diet of Berryteuthis magister (commander squid) within the Salish Sea using stomach content and stable isotope analyses. Squid samples were obtained through Fisheries and Oceans Canada midwater trawl surveys, and their dietary composition was assessed across different size classes. Stomach content analysis revealed a dietary transition occurring at approximately 160 mm dorsal mantle length (DML), where individuals shift from a crustacean-dominated diet to increased piscivory. This shift was confirmed by stable isotope analysis, which demonstrated a sigmoidal increase in δ¹⁵N values, corresponding to an approximately one trophic level rise with growth. The study found no significant dietary differences between sexes or sampling locations. These findings indicate that B. magister is not merely an opportunistic feeder but a selective predator, actively adjusting its foraging strategy in response to prey availability, capture efficiency, and energetic demands. This research provides the first comprehensive analysis of ontogenetic dietary shifts in B. magister in the Salish Sea, highlighting its role as both competitor and predator in structuring marine food webs. Understanding these trophic interactions is essential for refining ecological models and assessing broader ecosystem dynamics in the region.