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The Effects Of Dietary Mercury Exposure On Male Fertility In The Zebra Finch, Ananda Menon
The Effects Of Dietary Mercury Exposure On Male Fertility In The Zebra Finch, Ananda Menon
Dissertations, Theses, and Masters Projects
Sperm traits, including morphology, number and function, have been linked to fertilization ability and offspring quality in several species. However, many of these traits are artificially influenced by anthropogenic pollutants. Mercury, a globally distributed heavy metal pollutant, has been linked to altered testicular morphology and reduced fertility in many vertebrates. in this study, we exposed domestic male zebra finches (Taenopygia guttata) to dietary mercury at concentrations found in prey species in a highly polluted watershed region. We then compared sperm traits from these males to those of controls, and found a significant effect of mercury on sperm length and variability. …
Ecology And Evolution Of Common Milkweed, Angela Ricono
Ecology And Evolution Of Common Milkweed, Angela Ricono
Dissertations, Theses, and Masters Projects
All organisms must interact with and adapt to their surrounding environment. There are myriad ways in which species accomplish this; ultimately resulting in the vast diversity of life on earth today. Changes in the environment can have profound impacts on an organisms' ability to compete and utilize their surroundings. Plants are particularly impacted by local environmental differences because of the fact that they are immobile. This environmental variation exists at both large and small spatial scales. For example, on larger scales, forces such as fire and grazers can remove dominant plant competitors. on smaller scales, variation in resource availability (e.g. …
Immune Changes In The Anterior Kidney Of Spawning Sockeye Salmon, Meaghan K. Smith
Immune Changes In The Anterior Kidney Of Spawning Sockeye Salmon, Meaghan K. Smith
Dissertations, Theses, and Masters Projects
During the return journey to their spawning grounds, sockeye salmon are exposed to various pathogens and undergo major endocrine changes. Little is known about how these changes affect their immune system. The immune system of salmon is similar to mammals; myeloid lineage cells provide the first response to infection and B lineage cells protect against specific pathogens. After activation by pathogen, B cells may differentiate into long-lived plasma cells (LLPCs) in the anterior kidney, where they can survive for years, continuously secreting protective antibody. This research focused on salmon from two rivers, the Kenai and the Copper River, and characterized …
Investigating The Spatiotemporal Distribution Of A Tick-Borne Pathogen, Ehrlichia Chaffeensis, Dylan Simpson
Investigating The Spatiotemporal Distribution Of A Tick-Borne Pathogen, Ehrlichia Chaffeensis, Dylan Simpson
Dissertations, Theses, and Masters Projects
The incidence of tick-borne diseases is on the rise in the US and around the world, due in part to emerging pathogens. However, the environmental drivers affecting these pathogens remain unclear. Most research on the topic in the US has focused on Borrelia burgdorferi, which causes Lyme, but it is unknown if the same conditions that affect B. burgdorferi also affect other pathogens, which may be carried by other ticks or reservoirs. The answer will help determine generalizable principles in tick-borne pathogen ecology, if they exist, as well as better manage for tick-borne pathogen risk in areas at risk from …
Shifting Patterns Of Ribbed Mussel Distribution And Ecosystem Services In Response To Sea Level Rise, Robert Earl Isdell
Shifting Patterns Of Ribbed Mussel Distribution And Ecosystem Services In Response To Sea Level Rise, Robert Earl Isdell
Dissertations, Theses, and Masters Projects
Throughout the salt marshes of the US Atlantic Coast, ribbed mussels (Geukensia demissa, Dillwyn, 1817) and smooth cordgrass (Spartina alterniflora Loisel) form an important mutualistic relationship. Spartina provides habitat and promotes settling of ribbed mussels, which, in turn, stabilize and fertilize the Spartina and sediment. This relationship, however, is at risk of interruption due to sea level rise, erosion, and coastal development. Among the most at-risk segments of the marsh, the front (waterward) edge of the marsh is also where ribbed mussels and their ecosystem services are concentrated. Despite their importance of ribbed mussels to the salt …
Utilization Of Unnatural Amino Acids To Modulate Protein Structure And Function, John Halonski
Utilization Of Unnatural Amino Acids To Modulate Protein Structure And Function, John Halonski
Dissertations, Theses, and Masters Projects
Proteins are capable of an astounding array of functions using only the 20 canonical amino acids; however, the ability to add new functional groups to the genetic code through the utilization of unnatural amino acids (UAAs) has greatly expanded our ability to study and manipulate proteins. By expanding the diversity of functional groups within proteins, a wide variety of applications in industry as well as in fields such as diagnostics, biochemistry, and materials science are now possible. These applications have further been expanded through the development and optimization of bioorthogonal reactions which can occur under physiological conditions with a high …
Genetic Analyses Of Striped Bass In The Chesapeake Bay: An Investigation Of Connectivity Among Virginia Subestuaries And An Evaluation Of Close-Kinship Mark Recapture Methodology To Estimate Spawning Abundance., Savannah Michaelsen
Dissertations, Theses, and Masters Projects
The striped bass (Morone saxatilis) is an anadromous fish distributed along the eastern coast of North America that currently supports one of the most lucrative and important commercial and recreational fisheries in the region. Since the recovery of the Atlantic stock after a collapse in the late 1970s, studies have focused on understanding the connectivity of major spawning grounds and improving methods of abundance estimation. Studies support strong site fidelity of striped bass to major estuaries along the Atlantic coast, but there has been disagreement about connectivity within the largest spawning ground, the Chesapeake Bay. Additionally, no estimates exist for …
Consumption Patterns Of Chesapeake Bay Fishes, Christopher James Sweetman
Consumption Patterns Of Chesapeake Bay Fishes, Christopher James Sweetman
Dissertations, Theses, and Masters Projects
As fisheries management moves away from single-species approaches and towards more holistic, ecosystem-based approaches, physiological and ecological interactions need to be explicitly considered and mechanistically understood. Accurate portrayals of food web interactions and the direction and magnitude of energy flow between predator and prey populations are fundamental components to further develop ecosystem-based fisheries management (EBFM). to bolster information that is required within an EBFM framework in the Chesapeake Bay, I conducted research designed to advance traditional dietary studies and better understand the form and structure within the Bay's food web. This research relied on controlled feeding experiments, comprehensive sampling of …
Crab Larval Abundance And Settlement Patterns In A Changing Chesapeake Bay, Itchika Sivaipram
Crab Larval Abundance And Settlement Patterns In A Changing Chesapeake Bay, Itchika Sivaipram
Dissertations, Theses, and Masters Projects
All estuarine crabs have two larval stages, the zoea and the megalopa. Zoeae are entirely planktonic, whereas megalopae begin as plankton before beginning to search for settlement substrates as late stage megalopae. At both stages, crab larvae are subject to environmental conditions of the estuary. With changing environmental conditions due to anthropogenic activities and climate change, an understanding of how these planktonic larvae respond to environmental conditions is necessary for understanding subsequent larval supply to benthic populations and implication for fisheries management and habitat restoration. For this dissertation, I: 1) analyzed long-term timeseries in the lower Chesapeake Bay for spatial …
Multi-Scale Phylogenomics Of Gadiformes With Emphasis On Hakes (Merluccius, Merlucciidae), Adela Y. Roa-Varon
Multi-Scale Phylogenomics Of Gadiformes With Emphasis On Hakes (Merluccius, Merlucciidae), Adela Y. Roa-Varon
Dissertations, Theses, and Masters Projects
Gadiformes include some of the most important commercially harvested fishes in the world (e.g. cods, hakes, and grenadiers). Currently, different authors recognize anywhere between 11 and 14 families, approximately 84 genera, and over 600 species. The monophyly of the order has been supported by both morphological and molecular data, yet the relationships among families and subfamilies remain poorly understood and interpreting phylogenetic patterns to date has been difficult. My dissertation research on multi-scale phylogenetics of Gadiformes with emphasis on hakes (Merluccius, Merlucciidae) has three primary objectives: (1) to improve the understanding of the phylogenetic relationships among families of Gadiformes (Teleostei); …
Effects Of Anthropogenic Noise On Songbird Social Networks, Carly Elizabeth Hawkins
Effects Of Anthropogenic Noise On Songbird Social Networks, Carly Elizabeth Hawkins
Dissertations, Theses, and Masters Projects
Anthropogenic noise, which is increasing globally, affects birds from gene expression up through alteration of community composition. as urbanization pushes further into undisturbed habitat, noise often disperses birds away from the point source. The impacts of this dispersal on surrounding quieter areas is not well understood. Therefore, in the first chapter, we sought to understand how noise-related dispersal affected the sociality of groups of songbirds as they moved away from the source of noise. as the displaced birds would likely be forced to occupy a smaller area that may already have resident individuals, we predicted that displaced birds would show …
Acetylation Controls Thyroid Hormone Receptor Intracellular Localization And Intranuclear Mobility, Cyril S. Anyetei-Anum
Acetylation Controls Thyroid Hormone Receptor Intracellular Localization And Intranuclear Mobility, Cyril S. Anyetei-Anum
Dissertations, Theses, and Masters Projects
Thyroid hormone receptor (TR) is responsible for mediating the expression of genes involved in growth, development, and homeostatic regulation, in response to thyroid hormone. There are two main subtypes of TR, TRα1 and TRβ1, that mediate these physiological processes. Dysregulation of TR mediated processes is a contributing factor in disease pathology. Our prior studies show that TR is shuttled rapidly between the nucleus and cytosol, while localizing primarily to the nucleus. TRα1 contains two nuclear localization signals (NLSs) that act together to confer strong nuclear localization, while TRβ1 only contains one NLS (NLS-1). Recently, we found that the intracellular localization …
Range-Wide Variation In Common Milkweed Traits And Its Effect On Larvae Of The Monarch Butterfly, David De La Mater
Range-Wide Variation In Common Milkweed Traits And Its Effect On Larvae Of The Monarch Butterfly, David De La Mater
Dissertations, Theses, and Masters Projects
Plants play an important role in structuring ecological communities from the bottom up through interactions with herbivores, and environmental variation can affect these interactions. We use the interaction between common milkweed (Asclepias syriaca) and the monarch butterfly (Danaus plexippus) to examine 1) the role of environmental variation in dictating plants traits, and 2) how those variations affect herbivores. We quantified intraspecific trait variation in 53 natural common milkweed populations, then remeasured these traits when population representatives were regrown in a common garden to control for environmental variation. We then measured growth, performance, and survival of monarch larvae feeding on these …
The Eastern Oyster Microbiome And Its Implications In The Marine Nitrogen Cycle, Ann Arfken
The Eastern Oyster Microbiome And Its Implications In The Marine Nitrogen Cycle, Ann Arfken
Dissertations, Theses, and Masters Projects
Microbial communities associated with a particular space or habitat, or microbiomes, play significant roles in host health and the regulation of biogeochemical cycles. In oysters these microbiomes may be important contributors in the removal of biologically available nitrogen (N) from the coastal and marine environment through the process of denitrification. Denitrification is the microbially mediated step-wise reduction of nitrate (NO3-) or nitrite (NO2-) to N2 gas. Excess nitrogen in the Chesapeake Bay has been implicated in the increase of eutrophication and other detrimental effects including harmful algal blooms, hypoxia, and loss of benthic communities. Oyster reefs have been shown to …
The Role Of Ecological Interactions In Saltmarsh Geomorphic Processes, Bethany Lynn Williams
The Role Of Ecological Interactions In Saltmarsh Geomorphic Processes, Bethany Lynn Williams
Dissertations, Theses, and Masters Projects
Accelerated sea-level rise poses a significant threat to coastal habitats. Salt marshes are critical coastal ecosystems, providing a host of services such as storm protection, food production, and carbon storage. Persistence of salt marshes in the face of rising sea levels relies, in part, on vertical accretion. Current ecogeomorphic models and empirical studies emphasize the importance of the positive relationship between plant production and vertical accretion via sediment trapping by stems aboveground and belowground organic matter production. Thus, changes in plant production influence salt marsh persistence with sea-level rise. However, studies and models of marsh accretion do not consider the …
Carry-Over Effects In Complex Life Cycles: Linking Larval Food Supply With Juvenile Recruitment Success In Sea Stars, Emily Richardson
Carry-Over Effects In Complex Life Cycles: Linking Larval Food Supply With Juvenile Recruitment Success In Sea Stars, Emily Richardson
Dissertations, Theses, and Masters Projects
The supply of new individuals into a population is one of the most important factors impacting species distributions and ecological interactions within a community. For marine invertebrates with complex life cycles, the supply of new individuals into a population can be influenced by factors experienced throughout their life history—before, during, or after metamorphosis. In recent years, scientists have begun to take a more holistic approach to understanding marine population assemblages by considering links between early life stages. When experiences in the pre-metamorphic life stages impact post-metamorphic life stages, this is known as carry-over effects. Because carry-over effects impact fitness of …
Impacts Of Sea Level Rise On Tidal Wetland Extent And Distribution, Molly Mitchell
Impacts Of Sea Level Rise On Tidal Wetland Extent And Distribution, Molly Mitchell
Dissertations, Theses, and Masters Projects
Tidal marshes are a major ecological resource in Virginia and a driver of many estuarine functions. Therefore, the long term sustainability of tidal marsh ecosystems is a question of great interest in the research community. Sea level is rising at an unusually high rate in the Chesapeake Bay relative to most of the Atlantic coastline, putting Bay marshes at high risk from drowning and erosion. Sea level rise-driven salinity changes communities and alters ecosystem services. Understanding the patterns of change and the importance of different drivers of change is critical to tidal marsh sustainability. The overarching goal of this research …
Individual- And Population-Level Effects Of Temperature And Hypoxia On Two Demersal Fishes In Chesapeake Bay, Benjamin Marcek
Individual- And Population-Level Effects Of Temperature And Hypoxia On Two Demersal Fishes In Chesapeake Bay, Benjamin Marcek
Dissertations, Theses, and Masters Projects
Anthropogenically-induced climate change has resulted in increases in water temperature and the frequency and severity of hypoxic events in coastal areas worldwide. Temperature and hypoxia affect fishes' energetics which can, in turn, be reflected in changes in reproductive success and shifts in spatial distributions. in an effort to quantify these changes in Atlantic croaker (Micropogonias undulatus) and spot (Leiostomus xanthurus) in Chesapeake Bay. I: (1) estimated standard and maximum metabolic rates and hypoxia tolerances at five temperatures (10, 15, 20, 25 and 30°C) using intermittent-flow respirometry, (2) examined the effects of hypoxia exposure on metrics of reproductive potential and, (3) …
Reproductive Investment In Crassostrea Virginica As An Indicator Of A Tolerance Response To Perkinsus Marinus, Lauren Irene Huey
Reproductive Investment In Crassostrea Virginica As An Indicator Of A Tolerance Response To Perkinsus Marinus, Lauren Irene Huey
Dissertations, Theses, and Masters Projects
The Chesapeake Bay region values oysters for the ecosystem services, lucrative fishery, and historical significance that the species embodies; however, over the last half century, oyster abundances have been reduced to historical lows. Two protozoan parasites, Perkinsus marinus and Haplosporidium nelsoni, have been major influences on oyster populations, especially in high-salinity regions. Today, the population is recovering; catches have increased and oysters have expanded spatially. to investigate the cause of the recovery, three measurements were made on slides of oysters from a histological archive collected during summer at Wreck Shoal in the James River from 1988–2017: oocyte diameter, oocyte density, …
Assessing The Impact Of Land Use And Climate Change On Streamflow And Nutrient Delivery To The New River Estuary, Nc, Shanna Williamson
Assessing The Impact Of Land Use And Climate Change On Streamflow And Nutrient Delivery To The New River Estuary, Nc, Shanna Williamson
Dissertations, Theses, and Masters Projects
Freshwater inflow influences numerous physical, chemical, and biological characteristics of estuaries. The influx of freshwater to an estuary typically serves as an important source of allochthonous material from which primary producers derive their energy and transfer this energy to higher trophic levels. Any changes to freshwater flow subsequently impacts nutrient delivery and indirectly impacts organisms across multiple trophic levels. Anthropogenic changes to coastal land use and climate both act to threaten the integrity of estuarine systems by influencing freshwater inflow and dissolved nutrient input. Watershed loading models such as the Regional Nutrient Management (ReNuMa) model offer the ability to estimate …
Movements, Habitat Utilization, And Post-Release Survival Of Cobia (Rachycentron Canadum) That Summer In Virginia Waters Determined Using Pop-Up Satellite Archival Tags (Psats), Douglas Jensen
Dissertations, Theses, and Masters Projects
Cobia (Rachycentron canadum) is a cosmopolitan marine fish inhabiting tropical, sub-tropical, and temperate marine and estuarine waters. Recent changes in U.S. cobia management have sparked controversy and highlighted limitations in our understanding of seasonal movement patterns and problems with estimating recreational harvests. Consecutive years (2015 and 2016) of estimated overharvests from the Atlantic Migratory Group stock triggered accountability measures to prevent overfishing by recreational anglers. My project employed pop-up satellite archival tags (PSATs) to study cobia movements, habitat utilization, and post-release survival. It was, therefore, designed to enhance knowledge of cobia biology and aid sustainable management. We deployed 36 PSATs …
The Relationship Between Reproduction And Mortality In Triploid Crassostrea Virginica, Joseph L. Matt
The Relationship Between Reproduction And Mortality In Triploid Crassostrea Virginica, Joseph L. Matt
Dissertations, Theses, and Masters Projects
Unusual mortalities of cultured Crassostrea virginica in late spring have been reported from farms in the Chesapeake Bay from 2014 to 2017. None of the usual causes (e.g. disease, poor husbandry) were likely responsible, and mortalities occurred without clear signs of biological or physical stressors. Mortalities in the spring of 2014 were particularly high on over a dozen farms in Virginia, most of which were on the bayside of the Eastern Shore. Estimated losses were over 50%; however, mortalities only occurred within a four-week period between mid-May and early June. Farmers that had unusually high mortality in their crop were …
The Development Of Fiddler Crabs (Uca Spp.) As A Comparative Model System For The Parasitic Dinoflagellate, Hematodinium Perezi And Its Natural Host The Blue Crab, Callinectes Sapidus, Patricia Anne O'Leary
The Development Of Fiddler Crabs (Uca Spp.) As A Comparative Model System For The Parasitic Dinoflagellate, Hematodinium Perezi And Its Natural Host The Blue Crab, Callinectes Sapidus, Patricia Anne O'Leary
Dissertations, Theses, and Masters Projects
Herein, I have completed several experiments which encompass developing fiddler crabs as a model system, as well as sentinel and temperature studies to investigate biotic and abiotic factors in parasite transmission. My studies show which factors prevent, delay, or accelerate transmission and progression of H. perezi. The fiddler crab experiments by chapter are as follows: Chapter 1. I screened adult and juvenile fiddler crab populations for naturally occurring H. perezi infections at endemic and non-endemic sites. No natural infections were found in the adult or juvenile populations (Chapter 1 and 3). I completed inoculation trials with U. minax, U. pugnax, …
Improving Stock Assessments And Management Advice For Bluefin Tunas And Other Highly Migratory Species, Lisa Elma Ailloud
Improving Stock Assessments And Management Advice For Bluefin Tunas And Other Highly Migratory Species, Lisa Elma Ailloud
Dissertations, Theses, and Masters Projects
For years bluefin tuna has been the poster child for overfishing and poor management. However, recent improvements in data collection, catch monitoring and international cooperation are providing an opportunity to reverse the perception of a fishery that is doomed to collapse. Stock assessments are conducted routinely to monitor the abundance and productivity of exploited fish stocks so managers can determine how many fish can be sustainably harvested each year. Should a stock be declared overfished or under-going overfishing, the science behind stock assessments also equip managers with the knowledge necessary to make decisions about what short-term and long-term management measures …
Impacts Of Atmospheric Nitrogen Deposition And Coastal Nitrogen Fluxes On Chesapeake Bay Hypoxia, Fei Da
Impacts Of Atmospheric Nitrogen Deposition And Coastal Nitrogen Fluxes On Chesapeake Bay Hypoxia, Fei Da
Dissertations, Theses, and Masters Projects
Although rivers are the primary source of dissolved inorganic nitrogen (DIN) inputs to the Chesapeake Bay, direct atmospheric DIN deposition and DIN fluxes from the continental shelf can also significantly impact Chesapeake Bay hypoxia. The relative role of these additional sources of DIN has not previously been thoroughly quantified. In this study, the three-dimensional Estuarine-Carbon-Biogeochemistry model embedded in the Regional Ocean Modeling System (ChesROMS-ECB) is used to examine the relative impact of these three DIN sources. Model simulations highlight that DIN inputs from the atmosphere have roughly the same impact on hypoxia as the same gram for gram change in …