Digital Commons Network^™

Oyster Reef Connectivity Inferred Via Population Genetic Analysis, Brendan Douglas Turley

Dissertations, Theses, and Masters Projects

A panel of 48 single nucleotide polymorphism markers (SNPs) was developed for use in a population genetic analysis of the Eastern Oyster Crassostrea virginica sampled from the lower Chesapeake Bay. The SNPs were developed from published and unpublished sequencing data and developed to be used on a Fluidigm Biomark. A selection of 95 SNPs were chosen initially for development and the best 48 were selected for downstream applications. This project was a collaboration with the non-profit Chesapeake Bay Foundation (CBF) to examine their oyster reef restoration project in the Lafayette River, Virginia. The CBF wanted to test a hydrodynamic connectivity …

Bay Scallop, Argopecten Irradians, Restoration In The Virginia Coastal Bays: The Role Of Predation On Spring Vs Fall Cohort Survival, Erika L. Schmitt

Dissertations, Theses, and Masters Projects

While the importance o f predation in controlling many natural bivalve populations is well established, it is often overlooked in the restoration strategies for depleted populations. Adult bay scallops {Argopecten irradians concentricus) along the U.S. mid-Atlantic coast spawn multiple times per year, typically once in the early summer and again in the early fall. Larvae generally settle on seagrass leaves to avoid benthic predators, but shift to the sediment surface around 20 mm in size when they become less vulnerable to predation. The objectives o f this study were to 1.) Determine proportional survival o f two distinct size classes …

Signature Of Recent Sediment Accumulating In Prince William Sound, Alaska: A Record Of Storms, Earthquakes, And Seasonal Inputs, Nicole R. Marshall

Dissertations, Theses, and Masters Projects

This study focuses on the development o f provenance signatures for sediments accumulating in Prince William Sound, with an emphasis on interpreting mechanisms of sediment deposition using historical earthquake, wave, river discharge, and glacial outburst flood records. A highresolution sedimentary sequence in Prince William Sound, Alaska contains sediments sourced from local watersheds as a result of seasonal and event-driven sedimentation. This study contributes to the development of paleo-proxies for sediment provenance, earthquakes, shelf sediment resuspension, and Copper River discharge. Geochemical studies of sediment cores and end-member samples using X-ray fluorescence and inductively coupled plasma mass spectrometry allows for the development …

The Reproductive Biology Of Striped Bass (Morone Saxatilis) In Chesapeake Bay, Carissa L. Gervasi

Dissertations, Theses, and Masters Projects

The Striped Bass (Morone saxatilis) is an anadromous finfish that supports a lucrative fishery along the Atlantic coast of the United States and serves as a vital component of estuarine food webs. Once Striped Bass stocks were restored after crashing in the late 1980s, abundance skyrocketed to record levels. Over the past decade however, abundance has steadily declined, concurrent with an outbreak of mycobacteriosis. Disease prevalence is currently >50%, and previous research has demonstrated diseasepositive fish exhibit slower growth and increased natural mortality compared to diseasenegative fish. The purpose of this research was to provide a contemporary description of Chesapeake …

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 …

Diel, Seasonal, And Interannual Patterns In Mesozooplankton Abundance In The Sargasso Sea, Jami Alora Ivory

Dissertations, Theses, and Masters Projects

Temporal changes in mesozooplankton community structure are influenced by a combination of environmental factors. Epipelagic mesozooplankton biomass in the Sargasso Sea has increased over the last two decades, with a related increase in zooplankton-mediated carbon export. Unknown, however, are the patterns and variability at different temporal scales (diel, seasonal, and interannual) in abundance of each major zooplankton taxon, and how these patterns relate to physical and other environmental changes. I enumerated major taxa of mesozooplankton collected from monthly day and night net tows in the epipelagic zone at the Bermuda Atlantic Time-series Study (BATS) site in the Sargasso Sea from …

The Influence Of Short-Term Events On The Hydrographic And Biological Structure Of The Southwestern Ross Sea, Randolph M. Jones

Dissertations, Theses, and Masters Projects

Relative to the rest of the Southern Ocean, the Ross Sea continental shelf experiences very high productivity and phytoplankton biomass, which supports an extensive food web including high concentrations of upper trophic level biomass. Conventional observational methods, including ship-based sampling, instrumented moorings, satellite imagery, and computer-based modelling, have illustrated the seasonal progression of the phytoplankton bloom over the past four decades. While we have been sampling phytoplankton variability in the Ross Sea on a variety of relatively large scales, with observations at specific locations or times, over spans of time, or at specific depths, our understanding of smaller scales of …

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 …

Developing Methodologies For Studying Elasmobranchs And Other Data-Poor Species, Kristen L. Omori

Dissertations, Theses, and Masters Projects

Fisheries have become increasingly important to manage and conserve, and this is particularly challenging for data-poor species. Elasmobranchs are commonly considered data-poor or data-limited species. Their life history characteristics make their populations susceptible to depletion from fishing pressures and habitat degradation. Thus, it is important to understand the movement patterns and habitat use of the targeted species as well as the models used in the stock assessment for the species. This thesis involves developing techniques and information for data-poor species, such as elasmobranchs. The objectives of this research were to 1) identify the wintering grounds for the cownose rays (Rhinoptera …

The Influence Of Zostera Marina And Ruppia Maritima On Habitat Structure And Function In A Changing Environment In The Chesapeake Bay, Emily D. French

Dissertations, Theses, and Masters Projects

Seagrasses modify the coastal areas they occupy by trapping sediments and improving water clarity, providing habitat for marine animals, and cycling nutrients. Populations are in decline worldwide, and in the lower Chesapeake Bay, U.S., Zostera marina populations are decreasing due to poor water quality and high summertime temperatures. Ruppia maritima, a seagrass that is smaller, but has a greater tolerance of high temperatures than Z. marina, is replacing Z. marina in some areas. This study examined bed characteristics and microbial community structures of each seagrass species, as well as mixed assemblages, at three sites in the lower Chesapeake Bay where …

The Influence Of Environmental Factors And Resource Availability On Zostera Marina Flowering Intensity, Andrew J. Johnson

Dissertations, Theses, and Masters Projects

Sexual reproduction and the production of seeds are important for the resilience of all angiosperm species. For clonal species, such as the seagrass Zostera marina, resource allocation is complicated because these species reproduce both asexually and sexually, and the factors contributing to allocation to these two processes remains unknown. The goal of this study was, therefore, to investigate the importance of critical light, nutrient, and rhizome resources on Z.

marina sexual reproduction and flowering intensity. To evaluate the importance of sediment nutrients on Z. marina flowering intensity two distinct field manipulative experiments and one field survey were initiated: 1. Sediments …

A Model Of Carrying Capacity And Ecosystem Impacts In A Large-Scale, Bivalve-Dominated Agro-Ecosystem: Hard Clam Aquaculture In Cherrystone Inlet, Va, Michael A. Kuschner

Dissertations, Theses, and Masters Projects

With the recent growth of the hard clam aquaculture industry, sites of intensive aquaculture have emerged as large-scale agro-ecosystems where the success of aquaculture production is dynamically linked to ecosystem function. Large scale clam aquaculture operations are associated with a range of potential positive and negative feedbacks related to nutrient dynamics, water and sediment quality, proliferation of macroalgae, and carrying capacity. Quantitative modeling tools are needed to support system-level planning related to site selection, scale of operations, production capacity and ecosystem function. The purpose of this study was to develop a model for Cherrystone Inlet, VA, where one-third (1.9 km2) …