Digital Commons Network^™

From Rain Drops To Rivers: Unraveling Aridification's Influence On Coastal Stream Ecosystem Dynamics, Sean Kelly Kinard

Dissertations, Theses, and Masters Projects

This dissertation addresses the escalating threat of aridification to global freshwater ecosystems due to anthropogenic climate change, focusing on South-Central Texas, USA, using a space-for-time approach along a precipitation gradient from semi-arid to sub-humid. Over the 2017-2020 survey period, I integrated community, stable isotope, climate, and hydrologic data.In Chapter 2, my initial assessment of fish and invertebrate communities along the precipitation gradient unveiled compositional shifts and other nuanced responses. Positive correlations between fish diversity and rainfall, coupled with unexpected invertebrate diversity patterns, underscored the role of water quality in shaping fish assemblages. Drier conditions imposed abiotic filters, reducing diversity and …

Aggression In And Out Of The Surrounding Space, Marissa Incer

Undergraduate Honors Theses

Social isolation is a type of punishment used to address misbehavior in individuals, such as children with time-outs and prisoners in solitary confinement. It was thought to be an effective method for teaching good behavior or alleviating tense situations. However, this type of punishment may worsen the punished individual’s aggression depending on the environment of isolation. The current study was divided into two experiments. In the first experiment, participants were isolated in a small (2x2 feet) or large (6x6 feet) space to observe if the space alone affected their aggression. In the second experiment, a frustration-inducing task was given to …

The Effects Of Loss Of Orexin Neurons On Attention, Alejandra Eceizabarrena Sainz

Undergraduate Honors Theses

Attention is the ability to process stimuli in the environment and select relevant cues amongst distractors. It is a crucial aspect of the nervous system that engages multiple brain circuits. Neurons that release the neuropeptide orexin are implicated in attention. These neurons originate in the lateral hypothalamus and send projections widely throughout the brain. Evidence suggests orexins modulate attentional mechanisms through interactions with ascending neuromodulatory systems such as the basal forebrain. Experiments manipulating orexin receptors have found a subsequent effect on attention-demanding tasks, with infusions of orexin A enhancing attention in the presence of distractors. In contrast, the blockade of …

Fecal Pellet Production By North Atlantic Zooplankton, Michael Gibson

Undergraduate Honors Theses

Fecal pellet carbon (FPC) production by zooplankton is a significant component of the ocean’s biological carbon pump: the suite of biological processes that mediate export of carbon to the deep ocean, ultimately leading to the sequestration of atmospheric carbon dioxide in the ocean. In this study, mesozooplankton (zooplankton 0.2 mm to ~2 cm) were collected from the epipelagic zone in the temperate North Atlantic Ocean during day and night in May 2021. Zooplankton were live separated into five size fractions and incubated on board ship in natural surface seawater to measure fecal pellet production rate of the mixed mesozooplankton community. …

Place-Based Estuary Science Education At Machicomoco State Park, Anna Caputo

Dissertations, Theses, and Masters Projects

Project description:

This experiential estuary science field trip program was initially created as a master's capstone project by Anna Caputo in partnership with Machicomoco State Park, the Virginia Institute of Marine Science (VIMS), and the Chesapeake Bay National Estuarine Research Reserve (CBNERR). The ultimate goal of the project is to strengthen community estuarine literacy in the local area by teaching students who will be future marine scientists, community leaders, watermen, and environmentally conscious citizens. The program is designed to highlight the coastal habitats at the state park, the issues those habitats are facing, and how science and monitoring efforts done …

Is Diversity Dammed? Analysis Of Fish Diversity In Dammed And Undammed Estuary Streams Within The Virginia Peninsula Using Environmental Dna (Edna), Melinda Ann Spence

Dissertations, Theses, and Masters Projects

Anthropogenic activities are the leading cause to biodiversity decline worldwide. It has been well documented that large dams disrupt dispersal and alter local habitat often leading to less diverse aquatic systems. Yet, it is not well known how much more numerous smaller dams impact fish communities in estuary systems where dispersal is a critical part of the ecosystem, or how dams affect variation in species composition across sites (beta diversity). Coastal waterways of Virginia are impounded by hundreds of small dams. Here we used eDNA (environmental DNA) to assess the alpha, beta, and gamma diversity of fish species within the …

Tracing Atlantic Sea Scallops Using Radio Frequency Identification (Rfid) Technology, Will Shoup

Dissertations, Theses, and Masters Projects

Traceable seafood can be linked back to its origin and method of catch. Improving the traceability of marine organisms involves establishing a transparent Chain of Custody (CoC) by collecting data at checkpoints throughout the supply chain, from ship to shore to store. This report explores the feasibility of integrating Radio Frequency Identification (RFID) technology into the United States Atlantic sea scallop (Placopecten magellanicus) fishery in order to improve traceability. This report serves as a forward-looking evaluation of RFID technology that is intended to inform interested stakeholders of its functionality and capabilities. It is not intended to serve as a management …

Impact Of Substrate Type On Eastern Oyster (Crassostrea Virginica) Recruitment And Benthic Community Structure And Productivity In The York River, Jainita Patel

Dissertations, Theses, and Masters Projects

Restoration of eastern oyster (Crassostrea virginica) reefs in the Chesapeake Bay and its tributaries is important, as oyster reefs provide habitat for temperate estuarine communities and shoreline protection. Oysters that settle in crevices, such as those found on natural shell substrates, suffer low mortality, but natural shell is becoming a limited resource in the Chesapeake Bay. Finding an alternative settlement substrate that is complex like natural shell and mimics the benefits of shell substrates with less expense could be the best way to encourage oyster recruitment and survival. The two main goals of this experiment were to (1) understand which …

Empirical Valuation Of Primary And Alternative Nursery Habitats For The Blue Crab Callinectes Sapidus In Chesapeake Bay, Alexander C. Hyman

Dissertations, Theses, and Masters Projects

The blue crab (Callinectes sapidus) is a commercially and ecologically importantspecies found along the Atlantic coast of North and South America. These crustaceans play a critical role in coastal ecosystems, serving as both predators and prey in the food web. The blue crab supports a major fishery in Chesapeake Bay, where the species is a cultural icon. Juvenile blue crabs, the smallest and most vulnerable size classes of individuals, are reliant upon structurally complex habitats. Population dynamics of this species are therefore influenced by spatiotemporally fluctuating environmental variables, such as habitat availability. Understanding blue crab ecology is essential for managing …

Impacts Of Minuca Pugnax On Ecosystem Functioning In Its Historical And Expanded Range, Kayla Shanice Martinez-Soto

Dissertations, Theses, and Masters Projects

Animals across Earth are shifting or expanding their ranges because of climate change. These are climate migrants. Although climate migrants are well-documented, their impacts on recipient ecosystems are not. Climate migrants that are also ecosystem engineers (species that modify or create habitats) will likely have profound effects on ecosystem functioning. The Atlantic marsh fiddler crab, Minuca pugnax, is a burrowing crab that recently expanded its range into the northeast United States. The historical range of M. pugnax was between southern Cape Cod, Massachusetts and Daytona Beach, Florida (Grimes et al., 1989). In 2014, Johnson (2014) found that M. pugnax was …

From Field To Shore: Policy Improvements To Better Protect Ecosystem And Human Health From Poultry Wastes In Virginia, Rachael A. King

Dissertations, Theses, and Masters Projects

Commercial poultry production is a large industry with economic importance in Virginia. However, mismanagement of manures and wastes generated from the poultry industry can be a serious threat to ecosystem and human health. Primarily, there is a concern about nutrient pollution related to runoff and infiltration of poultry wastes. High nutrient loading can cause groundwater contamination, eutrophication, and harmful algal blooms (HABs). Additional concerns include metals, antibiotics, and pesticides that can be found in poultry wastes. To determine existing threats to ecosystem and human health from the poultry industry, Virginia policies regulating the industry are reviewed and their strengths and …

Comparing Low Salinity Transcriptomic Profiles Among Hard Clam, Mercenaria Mercenaria, Lines, Leslie Speight Youtsey

Dissertations, Theses, and Masters Projects

The hard clam is an important ecological and economic resource along the U.S. Eastern Seaboard. In Virginia alone, farm gate sales were estimated at $38.8 million in 2018 and $57.8 million in 2021, making Virginia the largest producer of hard clams in the U.S. This industry is primarily limited to higher salinity habitats on the seaside of the Eastern Shore of Virginia and lower Chesapeake Bay. Although the hard clam can be found in lower salinity habitats, they do not grow or survive at rates that are practical for productive aquaculture. Even in areas of higher salinity, hard clams are …

Hybridization As A Tool For Rapid Adaptation To Novel Environments In Virginia Asclepias, Casey Hensen

Dissertations, Theses, and Masters Projects

Plants, unlike animals, lack the ability to quickly move to desirable locations, which poses a challenge when faced with climate change. Here, we use anthropogenic forest canopy loss in the eastern United States as a model for understanding the effects of climate change. Removal of the forest canopy significantly alters the abiotic habitat, as does climate change, by increasing the variability of moisture, light, and temperature. One powerful mechanism plants can use to cope with environmental change is hybridization, as it provides novel genetic variation. Hybridization, followed by introgression, makes it possible to pass along adaptive traits between species, which …

Impacts And Uncertainties Of Climate Change On The Chesapeake Bay, Kyle E. Hinson

Dissertations, Theses, and Masters Projects

Climate change impacts in the Chesapeake Bay will limit the efficacy of nutrient reduction efforts and decrease dissolved oxygen, but uncertainties associated with the magnitude of these effects remain. An understanding of underlying mechanisms that have driven recent warming trends will narrow uncertainties for future pathways of temperature change. Additionally, future simulations of climate impacts in the estuary are dependent on multiple different sources of uncertainty, many of which have not yet been fully evaluated. This dissertation used a three- dimensional coupled hydrodynamic-biogeochemical model to investigate recent warming trends as well as underlying uncertainties likely to influence regional projections of …

Synthesis And Biological Testing Of Small-Molecule Mitochondrial Complex I Inhibitors, Willough Sloan

Undergraduate Honors Theses

This thesis delineates two main projects: the first outlines the structure elucidation efforts toward a Diels-Alder adduct of a novel reaction for the synthesis of chimaphilin, a naphthoquinone-based natural product with apoptotic or antiproliferative activity in certain cancer cells^1,2. The structure elucidation extends to derivatives of chimaphilin synthesized by the same cyclization reaction. While Diels-Alder reactions are usually regioselective, ¹H-NMR and ¹³C-NMR of the adducts was inconclusive and indicated the possibility of regioisomer presence, with one regioisomer being chimaphilin (or derivatives). A multitude of crystallization methods were carried out in order to be able to analyze …

The Cognitive & Educational Implications Of Color Use In Drawing To Learn, Juliana F.M. Cantarutti

Undergraduate Honors Theses

Drawing to Learn (D2L) is a learning aid that encourages STEM students to interact with abstract concepts in STEM by sketching. D2L is not an intuitive skill, and researchers strive to provide students with guidelines on how to master this method. One potential way to enhance the D2L method for students is by incorporation of visual cues, specifically color. While many students choose to incorporate color into their models without explicit instruction to do so, we have found no research on: a) why students use color in sketching, b) its effects on D2L. This study used interviews, surveys, and course …

Climate Change And Conservation Of Milkweed: Evidence Of Extensive Admixture Between Common Milkweed And Poke Milkweed, Elizabeth Davies

Undergraduate Honors Theses

Global climate change can drive many changes in species interactions. One primary way it affects species is by changing climates, causing species to expand their ranges and allowing them to interact with species from whom they were previously isolated. In plants, new species interactions can result in hybridization – the creation of hybrid offspring between two separate species. This hybridization can increase gene flow between the species and lead to introgression, the transfer of genetic material from one species to another through hybrid backcrossing with the parent species. My thesis investigates hybridization in the model system Asclepias (milkweed) by analyzing …

Using Deep Learning With Satellite Imagery To Estimate Deforestation Rates, Maeve Naughton-Rockwell

Undergraduate Honors Theses

Previous studies have used Convolutional Neural Networks for regional detection of deforestation breaks. However, there is limited research into the capability of deep neural networks to identify sudden shifts in global forest cover from satellite imagery. Additionally, many deforestation detection models are trained on region specific data and need manual input thresholds. In this work, we develop a deep learning model to predict the percent of deforestation in a region between two points in time, trained on globally sourced data. Using the before and after satellite images of a deforestation event as inputs, we implemented a two input Convolutional Neural …

Student Sleep Patterns When Exposed To Mindfulness Reminders, Zeyanna Dhalla

Undergraduate Honors Theses

University students are plagued with increased levels of stress and anxiety which can lead to poor sleep quality and quantity. Breathing techniques have demonstrated counteractive effects to the chronic stresses that the population encounters on an everyday basis. Wearable technology, such as Apple Watches, contain a mindfulness feature that encourages its users to pause throughout the day and engage in mindfulness through resonant breathing. Wearable technology has become increasingly accessible and is also growing in accuracy to measure different biometrics such as sleep quality and quantity. The purpose of the present study was to examine if the mindfulness reminders initiated …

Using A Machine Learning Model To Predict Plant Inflorescences Based Upon Its Soil Microbiome, Luke Denoncourt

Undergraduate Honors Theses

The UN estimates that the global population could reach 9.7 billion by 2050 (United Nations). As a result, the amount of food required to feed humanity is thought to double by 2050 (Ray et al., 2012). Humanity must find a way to increase crop production without increasing fertilizer usage and eutrophication, which can be done using the soil microbiome. Using potted plants with soils inoculated with Pseudomonas alcaligenes, Pseudomonas denitrificans, Bacillus polymyxa, and Mycobacterium phlei, both the shoot and root growth of pea and cotton plants was significantly increased (Egamberdieva & Höflich, 2004). In this study, utilizing a random forest …

Carrying Capacity Of Cultured Bivalves In Cherrystone Inlet, Va, And The Implications Of Spatial Distribution And Environmental Change, Sophia Chirico

Undergraduate Honors Theses

Aquaculture is a growing industry internationally. In the United States, aquaculture of bivalves occurs throughout the Chesapeake Bay. Cherrystone Inlet, a tidal inlet on the Virginia Eastern Shore, is the location of intensive hard clam culture, and recently oyster aquaculture has become common there as well. Given the intensive culture in Cherrystone and similar systems in the Chesapeake, it is important to understand the carrying capacity of the respective bivalves and how they can be grown together. Carrying capacity is defined here as the largest population of individuals that can be supported that allows individuals to reach a harvestable size …

Modeling And Analyses Of Mechanisms Underlying Network Synaptic Dynamics In Two Neural Circuits, Linda Ma

Undergraduate Honors Theses

In systems neuroscience, circuit models of cortical structures can be used to deconstruct mechanisms responsible for spike patterns that generate a variety of behaviors observed in the brain. In particular, mathematical simulations of these circuits can replicate complex dynamical behaviors that mirror not only macroscopically patterns observed in the brain, but also a significant amount of experimentally characterized minutiae. These models are capable of analyzing neural mechanisms by explicitly deconstructing connectivities between populations of neurons in ways that tend to be empirically inaccessible. This work presents two such models; one in the rat somatosensory barrel cortex, responsible for processing sensory …

Analysis Of Edna To Assess Effects Of Water Quality On Freshwater Fungal Diversity In A Virginia Coastal Watershed, Lauren French

Undergraduate Honors Theses

Freshwater fungi comprise a phylogenetically and functionally diverse group which contributes to wide-ranging ecosystem processes in aquatic systems. Saprotrophic fungi convert detritus into nutrient-rich food sources for fish and invertebrates, whereas pathogenic and parasitic fungi can cause disease and population declines of other aquatic organisms. With their diverse and important roles, changes in freshwater fungal community structure may have far-reaching impacts on ecosystems. To understand how natural and anthropogenic stressors to freshwater systems impact fungal-mediated ecosystem processes, a greater understanding of the taxonomic and functional composition of freshwater fungal communities is needed. We assessed relationships among freshwater habitat types, water …

Honey As A Biomonitor For Air Pollutant Deposition In The Eastern United States Using Ion Chromatography And Scanning Electron Microscopy, Cole Cochran

Undergraduate Honors Theses

Anthropogenic activities generate metal, acid, and particulate air pollutants which negatively impact human and ecological health. In the United States, power plant, industrial, and vehicle emissions are leading causes of air pollution, however, the measurement of air pollution at high-resolution spatial regimes remains a challenge. Honey has emerged as a powerful biomonitoring tool to effectively quantify contaminants without the need for a large array of monitoring instruments. I hypothesized that honey could be used to effectively measure and map modern air pollutant spatiotemporal relationships over the Eastern U.S. Using ion chromatography with sulfate as an indicator for air pollution and …

A Mathematical Model Of Vagus Nerve Stimulation In Alzheimer's Disease, Julianne Miranda

Undergraduate Honors Theses

Alzheimer’s Disease is a neurodegenerative condition characterized by cognitive decline as a result of brain atrophy. The exact cause of Alzheimer’s is unknown but current theories involve the aggregation of amyloid beta plaques as well as neurofibrillary tangles. Inflammation is emerging as central to the progression of the disease, with increased amyloid beta plaques and neurofibrillary tangles associated with the Nuclear Factor Kappa B pathway. This project presents a mathematical model of the impact of vagus nerve stimulation in Alzheimer’s Disease, as seen through the Nuclear Factor Kappa B (NFKB) pathway. The model examines several factors involved in the inflammatory …

Invertebrates In A Migrating Salt Marsh, Emily Marie Goetz

Dissertations, Theses, and Masters Projects

As sea-level rise converts coastal forest to salt marsh, marsh invertebrates may migrate inland; however, the resulting changes in forest and marsh invertebrate communities, including the stage of forest retreat that first supports saltmarsh species, remain unknown. Additionally, the ghost forest that forms in the wake of rapid forest retreat offers unknown quality of habitat to marsh invertebrates. In a migrating marsh on the Eastern Shore of Virginia, USA, ground-dwelling arthropod communities were assessed across the forest-to-marsh gradient, and the ecological equivalency of ghost forest and high marsh habitats was evaluated to determine if marsh invertebrates utilized expanded marsh in …

Environmental Ecology And Life History Variation Of Perkinsus Marinus, Lydia M. Bienlien

Dissertations, Theses, and Masters Projects

Marine resources provide a growing world population with the opportunity to increase food security, particularly through aquaculture. Oysters are prominent aquacultured species, but marine diseases are a threat to the growth and sustainability of oyster culture. Perkinsus marinus is the most important oyster pathogen of the Atlantic and Gulf coasts of the U.S., where it causes substantial mortality. Despite being one of the most well-studied protozoan parasites of bivalve molluscs, much is still unknown about P. marinus. This research investigated multiple characteristics of P. marinus.In Chapter Two, the environmental ecology of P. marinus was explored through tidal sampling and year-long …

The Role Of Zooplankton Community Composition In Fecal Pellet Carbon Production In The York River Estuary, Chesapeake Bay, Kristen Nicole Sharpe

Dissertations, Theses, and Masters Projects

The biological pump is a critical component of carbon transformation in aquatic ecosystems, but the role that zooplankton play in carbon production and vertical export is rarely studied in estuaries. Zooplankton produce carbon-rich fecal pellets which sink to depth and can fuel benthic community metabolism. The body size and taxonomic structure of the zooplankton community varies on interannual, seasonal, and diel time scales, and can lead to varying carbon production and export rates. We quantified fecal pellet carbon (FPC) production by the whole mesozooplankton community (> 200 µm) in the York River, a sub-estuary of Chesapeake Bay. Biomass and taxonomic …

Ecosystem Enriching And Efficient Solar Energy: Exploring The Effects Of Pollinator-Friendly Solar Facilities On Ecosystem Function And Solar Panel Efficiency, Jordan Martin

Dissertations, Theses, and Masters Projects

As the solar energy industry grows, many hundreds of thousands of acres of land will be transformed into solar panel facilities. With this large change in land use, there is the opportunity to promote biodiversity and support pollinators by using pollinator-friendly management practices at the solar facilities. This paper explores the ecological and economic effects of a pollinator-friendly solar facility compared to a turfgrass solar facility.

I hypothesized that a pollinator-friendly solar facility would be functionally equivalent in pollinator support and overall insect diversity to a pollinator-friendly non-solar field and that both sites would have far greater pollinator support and …

A Retrospective Analysis Of Atlantic Surfclam (Spisula Solidissima) Growth And Distribution In The Context Of A Changing Ocean, Alexis Hunter Hollander

Dissertations, Theses, and Masters Projects

Climate change is one of the greatest challenges the natural world currently faces, particularly in marine ecosystems, as many marine organisms are sensitive to warming water temperatures and other aspects of climate change. The Mid Atlantic Bight region is warming rapidly in comparison to the rest of the world’s oceans. In the face of climate change, organisms must either adapt to altered environmental conditions or shift their distribution to avoid extinction. One such example of the latter is the Atlantic Surfclam (Spisula solidissima), whose range has exhibited a shift over the past 4 decades, recorded in both stock assessments and …