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Articles 1 - 24 of 24
Full-Text Articles in Life Sciences
Evaluating The Impacts Of Land Use And Climate Change On The Hydrology Of Headwater Wetlands In The Coastal Plain Of Virginia, Pamela Braff
Evaluating The Impacts Of Land Use And Climate Change On The Hydrology Of Headwater Wetlands In The Coastal Plain Of Virginia, Pamela Braff
Dissertations, Theses, and Masters Projects
Located at the interface between uplands and surface water networks, headwater wetlands act as a natural filter to improve downstream water quality and play a critical role in maintaining the ecological integrity of downstream aquatic ecosystems. Vulnerable to development pressure, as well as indirect impacts from land use and climate change, the loss and alteration of headwater wetlands has been linked to the loss of biodiversity and regional water quality declines worldwide. The overall goal of this dissertation is to address some of the challenges associated with the management and conservation of headwater wetlands in the coastal plain of Virginia …
A Mechanistic Understanding Of Range Expansion Of Invasive Blue Catfish In The Chesapeake Bay Region, Vaskar Nepal
A Mechanistic Understanding Of Range Expansion Of Invasive Blue Catfish In The Chesapeake Bay Region, Vaskar Nepal
Dissertations, Theses, and Masters Projects
Blue catfish Ictalurus furcatus is an invasive species of great concern in coastal habitats throughout the eastern United States, inclulding the Chesapeake Bay and its tributaries. In this dissertation, I use field surveys, laboratory experiments and quantitative modeling to provide insights into several aspects of blue catfish biology at the individual level. In chapter 1, I characterize and compare patterns in growth and body condition in blue catfish populations in the James and York river subestuaries during two stages of invasion. Both the mean growth rate and mean body condition of blue catfish declined in the recent period in response …
Composition And Bioavailability Of Effluent Dissolved Organic Nitrogen, Quinn Nicole Roberts
Composition And Bioavailability Of Effluent Dissolved Organic Nitrogen, Quinn Nicole Roberts
Dissertations, Theses, and Masters Projects
Cultural eutrophication, the overproduction of phytoplankton biomass in response to increased nutrient inputs directly associated with human activities, is a major threat to the health of Chesapeake Bay. Strict regulations, which require a reduction in nutrient loading from all sources, have been a key component to restoration efforts. Water reclamation facilities (WRFs), which discharge effluent containing nitrogen (N) and other nutrients into receiving waters, have implemented upgrades in an effort to comply with regulations. These improvements have decreased the concentration of highly labile dissolved inorganic N (DIN), leaving behind significant concentrations of dissolved organic N (DON) whose bioavailability, and therefore …
Mercury Exposure And Chronic Food Stress Elevate Corticosterone In Blood But Not Feathers, Casey Lee Mclaughlin
Mercury Exposure And Chronic Food Stress Elevate Corticosterone In Blood But Not Feathers, Casey Lee Mclaughlin
Dissertations, Theses, and Masters Projects
Bird abundance in North America has declined by almost 30% in just the past 50 years. It is crucial that we understand the many factors contributing to declines, including the impacts of environmental contaminants. Mercury is a persistent and global neurotoxic contaminant of aquatic systems that will continue to increase in the environment as anthropogenic activities and climate change accelerate its emission. The impact of mercury on songbirds, a large and diverse but declining taxon, is not well understood. I sought to better understand the effects of mercury exposure on songbirds by studying its impact on the environmentally sensitive hypothalamic-pituitary-adrenal …
Effects Of Acidification And Salinity On Callinectes Sapidus, Mercenaria Mercenaria, And Their Interactions, Katherine Sara Longmire
Effects Of Acidification And Salinity On Callinectes Sapidus, Mercenaria Mercenaria, And Their Interactions, Katherine Sara Longmire
Dissertations, Theses, and Masters Projects
Ocean acidification (OA) coupled with other stressors, will be detrimental at the species and ecosystem levels. Decreased carbonate ion concentrations negatively impact calcifying species, yet the combined effects of OA and other stressors are less well known, and many studies disregard species interactions. Multi-species studies involving OA and other stressors are crucial to comprehend the full threat of OA. Understanding how OA interacts with other stressors to affect species responses is necessary for future management of exploited species in an altered ecosystem. The objectives of my study were to assess: 1) the effects of long-term exposure to decreased pH and …
Predicting The Impacts Of Climate Change On The Sandbar Shark And Cobia, Daniel P. Crear
Predicting The Impacts Of Climate Change On The Sandbar Shark And Cobia, Daniel P. Crear
Dissertations, Theses, and Masters Projects
A changing climate has been identified as a major driver of changes in marine species’ distribution, phenology, and habitat selection in recent decades and is expected to continue to influence these traits. These changes are not only happening in our oceans, but within coastal habitats as well, where waters are susceptible to sudden changes in temperature and oxygen levels are influenced by nutrient inputs. These changes which will likely impact fish species that utilize these areas as nurseries, spawning habitat, or foraging grounds. In this dissertation I consider climate impacts on two important predators, the sandbar shark (Carcharhinus plumbeus) and …
Search For Selection: Genomic, Transcriptomic, And Phenotypic Investigations Of Spotted Seatrout (Cynoscion Nebulosus), Jingwei Song
Search For Selection: Genomic, Transcriptomic, And Phenotypic Investigations Of Spotted Seatrout (Cynoscion Nebulosus), Jingwei Song
Dissertations, Theses, and Masters Projects
Climate change has resulted in both increased mean water temperature and higher frequencies of extreme water temperatures in coastal areas. These new thermal regimes exert strong selective pressure on the thermal physiology of coastal aquatic species. Phenotypic plasticity (the ability of one genotype to display multiple phenotypes) and local adaptation (increased fitness to local environment due to natural selection) dictate both short-term (from hours to days to weeks) and long-term (from years to decades) resilience of a species. To better predict how a species will respond to the negative impacts of climate change, one first needs to know the current …
Population Structure Of The Hard Clam, Mercenaria Mercenaria, Along The East Coast Of North America, Ann Janette Ropp
Population Structure Of The Hard Clam, Mercenaria Mercenaria, Along The East Coast Of North America, Ann Janette Ropp
Dissertations, Theses, and Masters Projects
Virginia leads the nation in production of aquacultured hard clams, Mercenaria mercenaria (Linnaeus, 1758), with an estimated farm gate value of $38.8 million in 2018. Despite the high economic value, there are few genomic resources available to support the hard clam aquaculture industry.To develop effective genetic tools for industry, it is important to first understand population structure. Hard clams have a pelagic larval phase that allows for dispersal, but the level of genetic connectivity among populations is not well understood. This study used genotyping-by-sequencing to delineate the genetic stock structure of wild clams sampled along the East Coast of North …
The Effect Of Slow Release Cortisol Implant On Humoral Immune Responses And Infection Prevalence Following Experimental Challenge With Flavobacterium Psycrophilum In Rainbow Trout (Oncorhynchus Mykiss), Fatima Quddos
Dissertations, Theses, and Masters Projects
Pacific salmon migrate long distances to spawn as part of their life cycle. During this journey from sea to their natal stream, they undergo major endocrine, physiological and immune changes. Cortisol, the primary stress hormone, gradually increases during the journey. Persistent high cortisol levels have deleterious health effects, including suppression of the antibody response. However, pathogens encountered during their journey may stimulate antibody responses to overcome the infection. My main research question focuses on how salmonids balance the immunosuppressive effects of high cortisol levels with activation of the antibody response. A recent field study from our lab showed a transient …
Reducing Avian Collisions With Human-Made Structures: A Sensory Ecology Approach To Open-Air Settings, Timothy James Boycott
Reducing Avian Collisions With Human-Made Structures: A Sensory Ecology Approach To Open-Air Settings, Timothy James Boycott
Dissertations, Theses, and Masters Projects
Billions of birds fatally collide with human-made structures each year. These mortalities have impacts on species of conservation concern and potentially on avian populations as a whole. This source of human-wildlife conflict also places economic and operational constraints on various human industries. Furthermore, with continued increases in urbanization, the rate and extent of collisions continues to increase. Efforts to reduce collisions have largely centered on making structures more visible to birds but have been met with limited success. Currently, there is a call for solutions to be tailored to both the environmental context of hazardous structures and to the sensory …
An Assessment Of The Population Genetic Structure And Evidence Of Multiple Paternity In Channeled Whelk, Busycotypus Canaliculatus, Along The Us Atlantic Coast, Samantha E. Askin
An Assessment Of The Population Genetic Structure And Evidence Of Multiple Paternity In Channeled Whelk, Busycotypus Canaliculatus, Along The Us Atlantic Coast, Samantha E. Askin
Dissertations, Theses, and Masters Projects
Channeled whelk (Busycotypus canaliculatus Linnaeus, 1758) are predatory marine gastropods that are found in intertidal regions of the continental slope along the U.S. Atlantic coast from Cape Cod, Massachusetts to Cape Canaveral, Florida. The channeled whelk is a commercially important species that supports a fishery along the Atlantic coast of the United States. The resource is managed at the state level with minimum landing size (MLS) varying by state. Biological assessments of channeled whelk in the mid-Atlantic and Massachusetts have indicated that females have a low probability of being mature when they enter the fishery. The life history characteristics of …
The Epibiont-Host Interaction Between Zoothamnium Intermedium And Estuarine Copepods, Lucia S.L. Safi
The Epibiont-Host Interaction Between Zoothamnium Intermedium And Estuarine Copepods, Lucia S.L. Safi
Dissertations, Theses, and Masters Projects
Ciliates are basal eukaryotes from Phylum Ciliophora that were first described 400 years ago, but their origins date back 800 million years. Such early origins have allowed contemporary ciliates to be remarkably diverse in both their species numbers and ecological adaptations. Peritrichia, a subclass of ciliates, represents an ideal model to study ciliate diversity, as its members display complex phylogenetic relationships and can be epibionts colonizing the body surface of other organisms. Epibiotic relationships are ecologically and evolutionarily important due to the extensive adaptations in epibiont biology to the life cycles of hosts. These relationships are also important for host …
Studies On The Anatomy Of Teleosts, Katherine Elliott Bemis
Studies On The Anatomy Of Teleosts, Katherine Elliott Bemis
Dissertations, Theses, and Masters Projects
The Longnose Lancetfish, Alepisaurus ferox, is a pelagic marine fish that has a heterodont dentition, including large fangs on both the upper and lower jaws. Their diet is well documented and includes salps, hyperiid amphipods, pelagic polychaete worms, mesopelagic fishes, and cephalopods. However, the function of the heterodont dentition, the structure of the teeth, and replacement mode is largely unknown. We studied a series of A. ferox to describe their dentition and tooth replacement. All teeth are replaced extraosseously. Palatine and dentary fangs develop horizontally in the oral epithelium on the lingual surface of dentigerous bones. Developing fangs rotate into …
Within-Flight-Period Dynamics Driven By Phenology And Transect Quality, Not Patch Size Or Isolation, In A Specialist Butterfly, Panoquina Panoquin, Sam Mason
Dissertations, Theses, and Masters Projects
As sea levels rise, coastal salt marshes, and the organisms for which they provision, face existential threats. A first step in understanding how projected marsh loss and reconfiguration may impact obligate species is to define their contemporary distribution and temporal shifts in structure using dynamic occupancy models. While occupancy models have commonly been applied to multi-annual butterfly studies, few have investigated population dynamics within a single-season. Here, we used Bayesian dynamic use models to define within-flight-period trends in adult salt-marsh skipper (Panoquina panoquin) use and state change probability. In doing so, we developed and validated a fully-Bayesian test for closure, …
Investigating Economic Costs Of Derelict Blue Crab Callinectes Sapidus Pots And Preferred Mitigation Solutions In The Chesapeake Bay, James Delbene
Investigating Economic Costs Of Derelict Blue Crab Callinectes Sapidus Pots And Preferred Mitigation Solutions In The Chesapeake Bay, James Delbene
Dissertations, Theses, and Masters Projects
Derelict fishing gear, particularly pots or traps, occupy waters worldwide and cause negative ecological and economic impacts. Derelict pots persist throughout Chesapeake Bay, the largest estuary in the U.S., that supports a valuable commercial fishery for the blue crab Callinectes sapidus. Chesapeake Bay is responsible for 30-40% of U.S. commercial blue crab harvests. Yet, few studies have quantified the impacts of derelict pots on harvest or the perceptions of commercial fishers on derelict pot mitigation activities in this predominantly pot fishery. This thesis examined the impacts of derelict pots on harvest in a field experiment and worked with commercial fishers …
The Impacts Of Acute Hypoxic Exposure And Other Concomitant Stressors On The Cardiorespiratory Physiology Of Coastal Elasmobranch Fishes, Gail Danielle Schwieterman
The Impacts Of Acute Hypoxic Exposure And Other Concomitant Stressors On The Cardiorespiratory Physiology Of Coastal Elasmobranch Fishes, Gail Danielle Schwieterman
Dissertations, Theses, and Masters Projects
This dissertation examines physiological stress responses of coastal elasmobranch fishes and investigates mechanisms that maintain oxygen delivery under stress. Elasmobranch fishes are, in general, understudied despite their susceptibility (due to K-selected life histories) to unsustainably high fishing mortality and the effects of climate change. Knowledge of physiological stress responses is, therefore, necessary to understand species-specific resilience and overall susceptibility to stressors. In Chapter II, I describe the hypoxia tolerances of clearnose skate (Rostaraja eglanteria), thorny skate (Amblyraja radiata), and summer flounder (Paralichthys dentatus, a representative teleost species) under conditions of temperatures and acidification projected to occur by the end of …
Environmental Controls On Pteropod Ecology And Physiology Along The Western Antarctic Peninsula, Patricia Susan Thibodeau
Environmental Controls On Pteropod Ecology And Physiology Along The Western Antarctic Peninsula, Patricia Susan Thibodeau
Dissertations, Theses, and Masters Projects
Pteropods (pelagic snails) are ubiquitous zooplankton in the Southern Ocean and abundant along the Western Antarctic Peninsula (WAP), one of the most rapidly warming regions on the planet. They are important prey for higher trophic levels, grazers of phytoplankton, and contribute to particulate organic and inorganic carbon export. Pteropods are heralded as bioindicators of ecosystem health due to the vulnerability of their aragonitic shells under ocean acidification conditions, which could greatly affect their abundances in the future. Despite their importance within Antarctic food webs, few studies have analyzed the effects of climate change on pteropod physiology and biogeography in the …
Semester-Long Instruction In Drawing For Biology Changes Study Habits, Motivation To Draw, And Approaches To Problem-Solving, Jessica Rose Burns
Semester-Long Instruction In Drawing For Biology Changes Study Habits, Motivation To Draw, And Approaches To Problem-Solving, Jessica Rose Burns
Dissertations, Theses, and Masters Projects
Model building can use drawing or sketching as a mechanism to help the drawer learn information (study), solve problems (model-based reasoning), and communicate. Unfortunately, many students fail to master drawing or sketching skills due to the effort and instruction required. Additionally, few longitudinal, real-world classroom studies have been conducted on the teaching of drawing to students. We applied guided practice of drawing or sketching to an undergraduate first-semester Introductory Biology majors course, aiming to assess (1) the patterns of growth and decline in the use of sketching and other active study methods over subsequent semesters, (2) the relationship between usage …
Chemical Warfare And Biofilm Formation In Multi-Strain Saccharomyces Cerevisiae Communities, Meredith Andersen
Chemical Warfare And Biofilm Formation In Multi-Strain Saccharomyces Cerevisiae Communities, Meredith Andersen
Dissertations, Theses, and Masters Projects
Microbial communities are ubiquitous in every ecosystem on earth, but the social interactions within these communities have only recently become a topic of investigation. Biofilms, the most common growth pattern found in nature, offer an exciting opportunity to study these interactions in a complex, spatially structured environment. This series of investigations explored the relationships between chemical warfare, a common competitive strategy, the three-dimensional spatial structure found in biofilms, and the phenotypic variation common in natural communities using Saccharomyces cerevisiae as a model organism. In the first set of experiments, the competitive effects of toxin production and biofilm formation were measured …
A Comparison Of Shorebird Habitat Use Between Living Shorelines And Natural Fringing Marshes, Robert Michael Galvin
A Comparison Of Shorebird Habitat Use Between Living Shorelines And Natural Fringing Marshes, Robert Michael Galvin
Dissertations, Theses, and Masters Projects
We examined the use of fringing marshes by herons and shorebirds in the southern portion of Chesapeake Bay. From 13 pairs of natural fringing marshes and nearby, constructed living shoreline marshes, we completed analysis of videos recorded at discrete, 30-minute intervals (dawn, dusk, high tide, low tide) throughout the 2018 and 2019 field seasons (May through August). A total of 684 hours of recording yielded 91 individual observations of birds comprising six species. Spotted Sandpipers (Actitis macularius) were observed most frequently (25), but only at living shoreline marshes. Likewise, 15 of 16 observations of Green Herons (Butorides virescens) were at …
The K. Marxianus Small Protein Modifier Sumo Enhances Stress Tolerance In The Mesophilic Yeast S. Cerevisiae, Yasaman Setayeshpour
The K. Marxianus Small Protein Modifier Sumo Enhances Stress Tolerance In The Mesophilic Yeast S. Cerevisiae, Yasaman Setayeshpour
Dissertations, Theses, and Masters Projects
SUMO, a small ubiquitin-like modifier protein, becomes attached to specific eukaryotic proteins to modulate their function and activity. The importance of SUMO modification in cell cycle progression, transcriptional regulation, and DNA damage-related processes has been firmly established. In contrast, a SUMO-dependent Stress Response (SSR) exists, but this process remains ill-defined. When cells are exposed to proteotoxic and genotoxic stressors, the SSR involves a rapid and dramatic increase in SUMO-modified proteins. The SSR is believed to play a cytoprotective role for normal cells, but it may also enhance the robustness of cancerous cells and eukaryotic pathogens. To test our hypothesis that …
Speciation Dynamics Of Diverging Allopolyploid Monkeyflower (Mimulus), Caroline Victoria Schlutius
Speciation Dynamics Of Diverging Allopolyploid Monkeyflower (Mimulus), Caroline Victoria Schlutius
Dissertations, Theses, and Masters Projects
Our understanding of speciation has been greatly improved with advances in genomic technology, but most of our knowledge of speciation is still built on research of diploid systems. Polyploids, however, are found in many lineages across the tree of life and exhibit considerably different evolutionary dynamics than diploids. Here, we investigate patterns of population structure and divergence in a system of two allopolyploid species of Mimulus (monkeyflower) that occur sympatrically in Chile: M. luteus and M. cupreus. We find that while the two species have consistent phenotypic differences across the range, they are genetically clustered into a northern and southern …
Genetic And Morphological Assessment Of Population Structure Of The Clearnose Skate (Rostroraja Eglanteria) From The Western North Atlantic Ocean, Lindsey Noel Nelson
Genetic And Morphological Assessment Of Population Structure Of The Clearnose Skate (Rostroraja Eglanteria) From The Western North Atlantic Ocean, Lindsey Noel Nelson
Dissertations, Theses, and Masters Projects
The Clearnose Skate (Rostroraja eglanteria, Bosc 1800) is a flat, benthic elasmobranch and member of the family Rajidae. They are widely distributed in the coastal waters of the east coast of the United States and in the northeastern Gulf of Mexico. It has been noted that the physical appearance of Clearnose Skate from the southern end of their range near South Carolina is distinct from individuals found in the northern end of their range near Woods Hole, MA, perhaps suggestive of a sub-species, though this observation has not been further investigated. Clearnose Skate are seasonally migratory and are often incidentally …
Morphology And Systematics Of Batrachoidiformes (Percomorphacea: Teleostei), Diego Francisco Biston Vaz
Morphology And Systematics Of Batrachoidiformes (Percomorphacea: Teleostei), Diego Francisco Biston Vaz
Dissertations, Theses, and Masters Projects
Batrachoidiformes, the toadfishes, are benthic fishes that inhabit nearshore subtidal and intertidal habitats, characterized by their dorsoventrally flattened bodies and large pectoral fins. These fishes lack dispersive larvae, and larval development is retained in nests guarded by their parents. To date, 82 species and 23 genera are accepted as valid. Previous studies recognized a single family, Batrachoididae, with four subfamilies: Batrachoidinae, Porichthyinae, Thalassophryninae, and Halophryninae. Interrelationships among subfamilies, however, are unresolved and interrelationships among species are problematic. Despite being a conspicuous member of the coastal fauna, the internal morphology of most species of Batrachoidiformes is unknown, being intraspecific and ontogenetic …