Physical Sciences and Mathematics Commons^™

Chesapeake Coastal Community Flood Vulnerability--Prediction And Verification, Alexander D. Renaud

Dissertations, Theses, and Masters Projects

Fast moving hurricanes and stationary nor’easters have resulted in significant flood damage in Chesapeake tidewater communities. The Chesapeake Bay region is one of A m erica’s most vulnerable regions with respect to sea-level rise, which will only increase storm surge impacts over upcoming decades. While the general trends are well documented, there is limited information relevant to specific communities’ relative flood risk and response. The dearth o f data is especially troublesome given the lengthy period o f time generally needed for communities to plan and implement adaptive action. This study contributes to the regional understanding of flood and sea-level …

The Effects Of Drifting Fish Aggregating Devices On Bycatch In The Tropical Tuna Purse Seine Fisheries In The Atlantic And Indian Oceans, Julia Snouck-Hurgronje

Dissertations, Theses, and Masters Projects

Thousands of floating objects, known as drifting fish aggregating devices (dFADs), are released every year by commercial tropical tuna purse seine vessels in the three equatorial oceans to aggregate tuna and increase catch. The escalation in the number of dFADs deployed over the last three decades has caused changes in fishing effort that are poorly reflected in traditional indices of purse seine effort and catch per unit of effort (CPUE). In addition, concerns have been raised regarding the impacts of such high numbers of dFADs being deployed on both catch and bycatch species. I studied two aspects of dFAD deployments …

Influence Of Perkinsus Marinus Infection And Oyster Health On Levels Of Human-Pathogenic Vibrios In Oysters, Lydia M. Bienlien

Dissertations, Theses, and Masters Projects

The eastern oyster Crassostrea virginica is an ecologically and commercially important species whose natural populations have been devastated by overharvesting, habitat destruction, and disease, but the rapid growth of oyster aquaculture has shown potential to restore the economic significance of this species. A key threat to the growth and sustainability of oyster aquaculture is the association of human-pathogenic Vibrio bacteria with product marketed for raw consumption. Two Vibrio species, Vibrio vulnificus and Vibrio parahaemolyticus, are the causes of the highest rates of seafood consumption-related mortality and gastrointestinal illness, respectively. Identification of the factors influencing V. vulnificus and V. parahaemolyticus prevalence …

Influence Of Structural Complexity And Location On The Habitat Value Of Restored Oyster Reefs, Melissa Ann Karp

Dissertations, Theses, and Masters Projects

In the Chesapeake Bay, < 1% of the historic oyster population remains, and efforts have been increasing to restore oysters and the services they provide. Building reefs that successfully provide ecosystem services–especially habitat and foraging grounds–may require different restoration techniques than those previously used, and success may depend on reef morphology (complexity), location, and environmental conditions. Salinity and habitat complexity are two important factors that may interact to effect benthic communities and predator-prey interactions on restored reefs. The goals of this project were: (1) Characterize the benthic communities on restored oyster reefs in lower Chesapeake Bay, and (2) examine the effects of structural complexity and salinity on benthic communities and predator-prey interactions. A two-year field survey of restored reefs was carried out in four rivers in lower Chesapeake Bay to characterize faunal communities on restored reefs and to quantify the effect of reef complexity on faunal communities. A laboratory mesocosm experiment was conducted to examine the effect of reef complexity on predator foraging. In total, 61 macrofaunal species were identified among all samples, and restored reefs supported on average, 6,169 org/m2 and 67.88 g-AFDW/m2. There were significant differences in the community composition and diversity among the rivers, and salinity was the environmental factor that best explained the observed differences in species composition across the rivers. Salinity and rugosity (i.e., structural complexity) both positively affected diversity, while salinity negatively affected macrofaunal abundance and biomass. Oyster density and rugosity positively affected macrofaunal biomass, and oyster density positively affected mud crab, polychaete, and mussel densities. In the mesocosm experiment, predator foraging, measured by proportion and number of prey consumed, was significantly reduced in the presence of oyster shell structure. However, predators were able to consume more prey when prey density was increased, even in the presence of oyster shell structure. These results combine to enhance our understanding of the benefits of increased habitat complexity for both prey and predators on restored oyster reefs. Increasing complexity worked to increase the abundance, biomass, and diversity of organisms inhabiting restored reefs, and even though predator consumption was reduced in the presence of structure compared to non-structured habitat, predators were able to consume more prey individuals when prey density was increased. Therefore, increasing the structure of oyster reef habitat may benefit prey species by providing refuge habitat, and benefit predators by providing an increased abundance of available prey items.

Assessing The Impact Of Climate Change On Proposed Restoration Of The Lynnhaven River Ecosystem, Emily E. Skeehan

Dissertations, Theses, and Masters Projects

Environmental degradation of the Chesapeake Bay (CB) and its sub-estuaries has been linked to population growth in the surrounding coastal zone, rapid development in the watershed and resultant nutrient loading into the Bay. Consequently, the federal government and its partners have developed restoration plans to mitigate the effects of eutrophication and improve essential ecosystem functions, though few restoration plans have considered the interactive effects of climate change. Climate change and other anthropogenic drivers are causing changes in ecosystem structure and function, thereby impacting the beneficial services ecosystems provide. While some studies have attempted to quantitatively predict the benefits of ecosystem …

Human Induced Cyclical Erosion Due To Altered Sediment Bypassing Mechanisms Of A Barrier Island And The Resultant Impact On The Housing Market, Andrew R. Fallon

Dissertations, Theses, and Masters Projects

No abstract provided.

Storm Event Impact On Organic Matter Flux, Composition And Reactivity In Taskinas Creek, Va, Sarah Schillawski Cammer

Dissertations, Theses, and Masters Projects

Carbon export from the land to the ocean are an important part of the global carbon cycle, linking terrestrial watersheds and the global carbon cycle. Burial of terrestrial organic carbon represents a long term sink for atmospheric CO2. Approximately 0.4 Pg Cy-1 is delivered to the global ocean from rivers, equally divided between POC and DOC. However, the amount of carbon entering the ocean is a small portion of the total amount entering rivers from the terrestrial environment, suggesting a large amount of processing in inland waters and estuaries. Most monitoring efforts have focused the processing of organic matter on …

Mercury Reduces Avian Reproductive Success Through Direct Embryotoxicity Rather Than Altered Parental Behavior, Stephanie Yen Chin

Dissertations, Theses, and Masters Projects

No abstract provided.

Impact Of Mercury Exposure On Birds And The Effect Of Molt On Mercury Depuration In Songbirds, Margaret Crossley Whitney

Dissertations, Theses, and Masters Projects

No abstract provided.

Effects Of Sub Lethal Methylmercury Exposure On Pigment Coloration In A Model Songbird, Jessica Lynn Spickler

Dissertations, Theses, and Masters Projects

No abstract provided.

Using A Sonic Net To Deter Pest Bird Species: Excluding European Starlings From Food Sources By Disrupting Their Acoustic Environment, Ghazi Mahjoub

Dissertations, Theses, and Masters Projects

No abstract provided.

Distribution And Impacts Of Invasive Bivalve Corbicula Fluminea In Tidal Freshwater York River Tributaries, Matthew Ryan Freedman

Dissertations, Theses, and Masters Projects

The Asian clam, Corbicula fluminea, is one of the most invasive bivalves in the world but there is limited research on its presence in tidal freshwater systems. Despite its introduction into Chesapeake Bay tributaries in the 1970s, the initial colonization and subsequent development of populations of C. fluminea in the Mattaponi and Pamunkey sub-tributaries of the York River, Virginia, is mostly undocumented. This study assessed the spatial distribution and population structure of C. fluminea in tidal freshwater sections of these rivers (~45km) with benthic surveys during summer 2011 – 2012. Benthic grabs (2.4L, 0.023m2) taken at 40 sites in each …

The Development Of Ecological Functions In Created Forested Wetlands, Sean P. Charles

Dissertations, Theses, and Masters Projects

Wetland mitigation has become a 2.4 billion dollar per year industry in the U.S. and in Virginia it leads to the replacement of 77 ha of palustrine forested wetlands (PFWs) per year with mitigation wetlands, including created forested wetlands (CFWs). Mitigation hinges on the idea that compensation wetlands lead to “no net loss of wetland function” when compared to impacted wetlands. We assessed the functions of provision of habitat and biogeochemical functions associated with production of biomass, the retention and removal of nutrients and the accumulation of soil C over 8 years in seven CFWs of approximately 11 and 20 …

Ecologically-Framed Mercury Database, Exposure Modeling And Risk/Benefit Communication To Lower Chesapeake Bay Fish Consumers, Xiaoyu Xu

Dissertations, Theses, and Masters Projects

Mercury concentrations and determinants of mercury accumulation were examined for ten finfish species from the lower Chesapeake Bay and its tributaries. None of the sampled fish had total mercury concentrations approaching the U.S. EPA human health screening value. Mercury concentrations in different fish species generally increased with increasing delta 15N, but not delta 13C, suggesting that trophic position, but not dietary carbon source was a dominant determinant. A methylmercury biomagnification model was built to estimate a food web magnification factor of approximately 10-fold increase per trophic level in Chesapeake Bay. Based on otolith strontium-calcium ratios, Atlantic croaker inhabiting less saline …

Modeling The Formation Of Periodic Hypoxia In Partially Mixed Estuaries And Its Response To Oligotrophication And Climate Change, Samuel J. Lake

Dissertations, Theses, and Masters Projects

The development of hypoxia represents one of the most common and ecologically detrimental effects of anthropogenic nutrient enrichment in coastal marine ecosystems. Due to the physiological importance of oxygen as a key component of metabolic processes, the development and persistence of hypoxia can reduce the distribution of important species, modify food webs, decrease diversity and richness, and sub-lethally affect growth and reproductive rates. While many recent studies have focused on the global increase in hypoxia and highlighted the need for nutrient reduction strategies, some key processes associated with hypoxia remain understudied. of particular importance is the resolution of the major …

Habitat And Fish Population Dynamics: Advancing Stock Assessments Of Highly Migratory Species, Patrick D. Lynch

Dissertations, Theses, and Masters Projects

Fisheries sustainability is inherently linked to an understanding of the population-level effects of fishing. With an accurate characterization of historical fish and fishery dynamics, management agencies are more equipped to create regulations that sustain fishery resources over the long term. The overarching goal of this dissertation is to contribute to the advancement of fisheries stock assessment and promote resource sustainability. My research focused on highly migratory species (HMS), particularly fishes that reside in the open ocean. These species constitute some of the highest valued global fisheries; however, numerous factors compromise HMS stock assessment and management. These challenges are fully described …

Sublethal Effects Of Methylmercury On Flight Performance And Molt In European Starlings (Sturnus Vulgaris), Jenna Rae Carlson

Dissertations, Theses, and Masters Projects

No abstract provided.

Methylmercury Exposure Affects Risk-Taking Behaviors In Zebra Finches: Tradeoffs Between Eating And Being Eaten, Megan Elizabeth Kobiela

Dissertations, Theses, and Masters Projects

No abstract provided.

Are Occupancy Models Feasible Alternatives To Collecting Breeding Data?, Morgan D. Niccoli

Dissertations, Theses, and Masters Projects

No abstract provided.

The Consequences Of Shoreline Development For Near-Shore Communities In Chesapeake Bay, Usa: A Before-After Control-Impact Study, Theresa M. Davenport

Dissertations, Theses, and Masters Projects

Hardened shorelines and their construction introduce stressors to a system by altering near-shore habitats. They can reduce biodiversity and abundance of benthic infauna and marsh-edge nekton and epifauna. In this study, I investigated the impacts of shoreline development on near-shore communities using a temporal and spatial approach, by use of a before-after control-impact (BACI) study design at four sub-estuaries within Chesapeake Bay that represent three different types of shoreline change. The BACI study was used to examine infaunal density, biomass, and diversity for two size classes of infauna (3-mm: larger species and adults, 500-!m: smaller species and juveniles), as well …

Evaluating Persistent Organic Pollutants (Pops) And Mercury In The West Antarctic Peninsula (Wap) Food Web, With A Focus On Antarctic Fur Seals (Arctocephalus Gazella), Emily K. Brault

Dissertations, Theses, and Masters Projects

No abstract provided.

Unprecedented Restoration Of A Native Oyster Metapopulation, David M. Schulte

Dissertations, Theses, and Masters Projects

No abstract provided.

Movements, Growth, And Mortality Of Chesapeake Bay Summer Flounder Based On Multiple Tagging Technologies, Mark J. Henderson

Dissertations, Theses, and Masters Projects

The research projects presented in this dissertation used multiple tagging technologies to examine the movements, growth, and mortality rates of summer flounder tagged and released in Chesapeake Bay. In the first two chapters, I used acoustic, archival, and conventional tags to examine the behavior of summer flounder on different spatial scales. Investigating the movement behavior of individuals on different scales is an important step towards understanding how large-scale distributions of a population are established. Based on the observed behaviors of summer flounder, I hypothesize that the movements of these fish are primarily related to foraging behavior while they are resident …

A Community-Based Participatory Assessment Of Fish Consumption And Dietary Mercury Exposure Along The Lower James River, Virginia Usa, Erica Lynnette Holloman

Dissertations, Theses, and Masters Projects

The use of community-based participatory research (CBPR) methods to conduct environmental exposure assessments provides valuable insight about disparities in fish consumption and contaminant exposure. Ninety-five community-specific fish consumption surveys were administered to low-income African American women (ages 16--49) residing in the Southeast community of Newport News, Virginia, USA, in 2008. The mean fish consumption rate for the women surveyed was 147.8 g/day (95% CI: 117.6-185.8), a rate substantially higher than the mean fish consumption rate reported for U.S. women (1.8 g/day 95% CI: 1.51-2.04). Through collaborative partnerships established between current researchers and The Moton Community House (a local community center), …

Effects Of Anthropogenic Stressors And Changes In Biodiversity On Lower Chesapeake Bay, Va Usa Seagrass Systems, Rachael E. Blake

Dissertations, Theses, and Masters Projects

Anthropogenic stressors are increasingly changing conditions in coastal areas and impacting important habitats. But, when multiple stressors act simultaneously, their effects on ecosystems become more difficult to predict. In Chesapeake Bay, USA, predictions suggest that anthropogenic stressors from climate change, such as warming temperatures, may increase the frequency and severity of storm events, leading to increased freshwater, nutrient, and sediment inputs. Coastal development, another source of anthropogenic stressors, continues to increase with growing coastal populations, and may lead to altered sediment characteristics, habitat fragmentation, altered food webs, and loss of vegetated habitats. Community processes may interact with stressors, for example, …

A Case Study In The Effectiveness Of Marine Protected Areas (Mpas): The Islands Of Bonaire And Curacao, Dutch Caribbean, Noelle J. Relles

Dissertations, Theses, and Masters Projects

The islands of Bonaire and Curacao, Dutch Caribbean, were both mapped along their leeward coasts for dominant coral community and other benthic cover in the early 1980s. This mapping effort offers a unique baseline for comparing changes in the benthic community of the two islands since that time, particularly given the marked differences between the two islands. Bonaire is well-protected and completely surrounded by a marine protected area (MPA), which includes two no-diving marine reserves; additionally, Bonaire's population is only around 15,000. In contrast, the island of Curacao is home to 140,000 inhabitants and marine protection is limited, with a …

Microburst Damage Assessment And Forest Composition Reconstruction After Hurricane Isabel In The College Woods, Williamsburg, Va, Kjarstin Alane Carlson-Drexler

Dissertations, Theses, and Masters Projects

No abstract provided.

Sublethal Effects Of Methylmercury On The Songbird Immune Response: An Experimental Study, Catherine Ann Lewis

Dissertations, Theses, and Masters Projects

No abstract provided.

Mercury Exposure Assessment Of South River Floodplain Birds, Jincheng Wang

Dissertations, Theses, and Masters Projects

The studies involved in this thesis expanded the current project being conducted in Dr. Newman’s laboratory that aimed to define and quantify the impacts of mercury movement in contaminated aquatic and terrestrial food webs in the South River watershed (Virginia, USA). This expansion involved a two phase study, which fulfilled the requirement of a master thesis.

Previous research in our lab documented mercury biomagnification in the river itself and two floodplain locations on the South River watershed. Predictive models were built for mercury concentration in members of these food webs. These studies reached a preliminary conclusion that mercury biomagnification in …

The Impacts Of Shoreline Development On Shallow-Water Benthic Communities In The Patuxent River, Md, Cassie D. Bradley

Dissertations, Theses, and Masters Projects

Natural coastal habitats throughout Chesapeake Bay are increasingly threatened with shoreline modification due to population growth and rising rates of development. The replacement of these natural coastlines with hardened structures such as seawalls (bulkheads) and stone revetments (riprap) not only compromises vegetation at the land-water interface, but also can influence several elements of local aquatic food webs. Effects of these alterations have been well-studied with respect to fish assemblages and intertidal communities, particularly in conjunction with larger-scale watershed development, and recently, interest has shifted toward investigation of the effects of shoreline development on subtidal benthic infaunal communities.
This study evaluated …