Marine Biology Commons^™

Quantifying Nutrient Fluxes Across The Sediment-Water Interface In The Lafayette River Estuary, Adriana E. Amrhein

OES Theses and Dissertations

The Lafayette River, a shallow, eutrophic tributary of the Chesapeake Bay, experiences seasonal harmful algal blooms (HABs). While management efforts focus on reducing external nutrient inputs, internal loading from benthic sediments remains poorly constrained. This study quantifies spatial and seasonal variability in nutrient and radium isotope fluxes across the sediment–water interface at three sites where HABs are known to initiate and represent contrasting sediment textures and hydrodynamic conditions. Sediment cores and porewater samples were collected in summer 2023 and winter 2024 to measure grain size, porosity, dissolved nutrients (NH₄⁺, NOₓ⁻, PO₄³⁻), and radionuclide activities (²²⁴Ra and ²²⁸Th). Radium isotope disequilibrium …

Margalefidinium Polykrikoides Group Iii Va, Usa Strain Growth And Sac-Like Pellicle Cyst Dynamics, Eduardo Pérez Vega

OES Theses and Dissertations

Margalefidinium polykrikoides is a harmful cosmopolitan dinoflagellate that blooms in coastal waters. The effect of temperature and salinity on the growth of M. polykrikoides VA strain was examined using microscopy and growth models. M. polykrikoides Group III VA strain grew better at warmer temperatures and lower salinities than M. polykrikoides Group III NY strain, Group I Korea strain, and Japan strain (unknown group). Modelers need to use the temperature and salinity growth responses from M. polykrikoides Group III VA strain to better simulate and predict M. polykrikoides blooms in the Chesapeake Bay.

Dinoflagellates produce cysts as a strategy to withstand …

Ocean Acidification Mitigation: Potential Expansion Of Sav Restoration Strategy In The Chesapeake Bay, Cree N. Taylor

UROP Posters

Zostera marina is a species of marine macrophyte that has been largely prioritized in past submerged aquatic vegetation (SAV) restoration initiatives within the Chesapeake Bay because of its 1) previous abundance, 2) demonstrated carbon burial abilities, and 3) observed ability for meadows of Z. marina to ameliorate low pH conditions. Due to the temperature variability and poor water quality associated with anthropogenic disturbances in the Chesapeake Bay, Z. Marina beds have experienced several die-off events with limited capacity for regrowth. This systematic review explored the possible benefits of focusing future SAV recovery initiatives on ensuring a diverse variety of SAV …

Biophysical Interactions Control The Progression Of Harmful Algal Blooms In Chesapeake Bay: A Novel Lagrangian Particle Tracking Model With Mixotrophic Growth And Vertical Migration, Jilian Xiong, Jian Shen, Qubin Qin, Michelle C. Tomlinson, Yinglong J. Zhang, Xun Cai, Fei Yi, Linlin Cui, Margaret R. Mulholland

OES Faculty Publications

Climate change and nutrient pollution contribute to the expanding global footprint of harmful algal blooms. To better predict their spatial distributions and disentangle biophysical controls, a novel Lagrangian particle tracking and biological (LPT-Bio) model was developed with a high-resolution numerical model and remote sensing. The LPT-Bio model integrates the advantages of Lagrangian and Eulerian approaches by explicitly simulating algal bloom dynamics, algal biomass change, and diel vertical migrations along predicted trajectories. The model successfully captured the intensity and extent of the 2020 Margalefidinium polykrikoides bloom in the lower Chesapeake Bay and resolved fine-scale structures of bloom patchiness, demonstrating a reliable …

Mycobacteriosis Of Striped Bass (Morone Saxatilis) In Virginia Tributaries Of The Chesapeake Bay, Joshua S. Mcgilly

Biological Sciences Theses & Dissertations

Mycobacteriosis was first documented in Chesapeake Bay striped bass (Morone saxatilis) in 1997 after fish exhibited emaciation and skin lesions. Since it was first identified, studies of mycobacteriosis in the mainstem of the Chesapeake Bay (2003-2007) and the Rappahannock River (2005-2012) have shown high disease prevalence and disease-associated mortality. Until this study, no current prevalence data existed from the Rappahannock River, and no published prevalence data existed for the James River, leaving a gap in our understanding of this disease in major Chesapeake Bay tributaries. We began gathering mycobacteriosis prevalence data from an existing survey collecting striped bass …

Nutrient Controls Over Cyanobacterial Synthesis Of The Neurotoxin Β-N-Methylamino-L-Alanine (Bmaa) And Its Potential Accumulation In The Blue Crab (Callinectes Sapidus), Madeline M. Hummel

OES Theses and Dissertations

Cyanobacteria are known to produce a variety of toxins that negatively impact both aquatic and terrestrial organisms. One putative neurotoxic compound is the non-protein amino acid β-N-methylamino-L-alanine (BMAA), which has epidemiological linkages to the development of several human neurological diseases. Three cyanobacterial species thought to produce BMAA —Microcystis aeruginosa, Synechococcus bacillaris, and Nostoc sp. —were grown in nutrient replete cultures to examine its synthesis and cellular distribution over a growth cycle. Production of BMAA was also examined in nutrient (nitrogen and phosphorus) deplete cultures of Microcystis aeruginosa. In addition, natural assemblages of phytoplankton dominated by …

Factors Contributing To The Success Of Restored Oyster Reefs In The Choptank River Of The Chesapeake Bay, Virginia, Tara L. Bardar

HCNSO Student Capstones

Populations of Crassostrea virginica, the Eastern oyster, have been declining since the late 1800s. While overharvesting is the primary cause of decline, the Eastern oyster is also facing the threat of disease and habitat loss. As oyster populations decline, habitat suitable for oyster spats declines as well, as these prefer to settle on the shells of other oysters that have formed reefs. Knowing this, oyster restoration projects have been focused around testing methods that will increase recruitment of spat and allow oyster reefs to form. A current and ongoing restoration project in the Choptank River of the Chesapeake Bay, …

Beyond Zar: The Use And Abuse Of Classification Statistics For Otolith Chemistry, C. M. Jones, M. Palmers, J. J. Schaffler

OES Faculty Publications

Classification method performance was evaluated using otolith chemistry of juvenile Atlantic menhaden Brevoortia tyrannus when assumptions of data normality were met and were violated. Four methods were tested [linear discriminant function analysis (LDFA), quadratic discriminant function analysis (QDFA), random forest (RF) and artificial neural networks (ANN)] using computer simulation to determine their performance when variable-group means ranged from small to large and their performance under conditions of typical skewness to double the amount of skewness typically observed. Using the kappa index, the parametric methods performed best after applying appropriate data transformation, gaining 2% better performance with LDFA performing slightly better …

Chesapeake Aquaculture, Garth Woodruff

Faculty Publications

No abstract provided.

Biodiversity And You., Garth Woodruff

Faculty Publications

No abstract provided.

Benthic And Planktonic Microalgal Community Structure And Primary Productivity In Lower Chesapeake Bay, Matthew Reginald Semcheski

Biological Sciences Theses & Dissertations

Microalgal populations are trophically important to a variety of micro- and macroheterotrophs in marine and estuarine systems. In Chesapeake Bay, microalgae facilitate the survival and development of ecologically and economically relevant fauna, including shellfish and finfish populations. While regarded as significant components of coastal environments, microphytobenthic communities are historically understudied. In Chesapeake Bay, the importance of phytoplankton to the ecosystem is understood, but the contribution of microphytobenthos remains unclear. This project surveys intertidal microphytobenthic communities, in relation to phytoplankton communities, around lower Chesapeake Bay describing the taxonomic makeup of these populations, coupled with quantification of cell abundance, biomass, and primary …

Determination Of The Ecological Condition Of Benthic Communities Affected By Polycyclic Aromatic Hydrocarbons In The Elizabeth River, Chesapeake Bay, Usa, Adam M. Webb

Biological Sciences Theses & Dissertations

The Southern Branch of the Elizabeth River, a tributary of Chesapeake Bay, has historically been polluted with hydrocarbon based industrial by-products. My study compared benthic community condition from two locations in the Southern Branch: the subtidal region near Money Point, historically affected by pollution of polycyclic aromatic hydrocarbons (PAHs), to a subtidal region near Blows Creek on the opposite shore that is putatively designated as unimpacted by P AH contamination. Samples from both study sites in the Southern Branch were compared to the benthic community condition of samples from the same habitat type designations collected as part of the Chesapeake …

Can We Predict The Future: Juvenile Finfish And Their Seagrass Nurseries In The Chesapeake Bay, Cynthia M. Jones

OES Faculty Publications

The importance of estuarine seagrass beds as nurseries for juvenile fish has become a universal paradigm, especially for estuaries that are as important as the Chesapeake Bay. Yet, scientific tests of this hypothesis were equivocal depending on species, location, and metrics. Moreover, seagrasses themselves are under threat and one-third of seagrasses have disappeared worldwide with 65 of their losses occurring in estuaries. Although there have been extensive studies of seagrasses in the Chesapeake Bay, surprisingly few studies have quantified the relationship between seagrass as nurseries for finfish in the Bay. Of the few studies that have directly evaluated the use …

Emergence Of Algal Blooms: The Effects Of Short-Term Variability In Water Quality On Phytoplankton Abundance, Diversity, And Community Composition In A Tidal Estuary, Todd A. Egerton, Ryan E. Morse, Harold G. Marshall, Margaret R. Mulholland

OES Faculty Publications

Algal blooms are dynamic phenomena, often attributed to environmental parameters that vary on short timescales (e.g., hours to days). Phytoplankton monitoring programs are largely designed to examine long-term trends and interannual variability. In order to better understand and evaluate the relationships between water quality variables and the genesis of algal blooms, daily samples were collected over a 34 day period in the eutrophic Lafayette River, a tidal tributary within Chesapeake Bay's estuarine complex, during spring 2006. During this period two distinct algal blooms occurred; the first was a cryptomonad bloom and this was followed by a bloom of the mixotrophic …

How Do Shellfisheries Influence Genetic Connectivity In Metapopulations? A Modeling Study Examining The Role Of Lower Size Limits In Oyster Fisheries, Daphne M. Munroe, Eileen E. Hofmann, Eric N. Powell, John M. Klinck

CCPO Publications

Fisheries can potentially alter evolutionary processes such as genetic connectivity and lead to genotypic changes in stocks. Using an individual-based metapopulation genetics model, we examined the possible influence of oyster (Crassostrea virginica) fisheries on genetic connectivity. We simulated a range of realistic fishing pressures, with and without a minimum size limit (limit = 63.5 mm), over a range of fishing scenarios including single-area and stock-wide fisheries. Movement of a neutral marker gene provided an indicator of gene transfer between populations. Simulations showed that fishing may alter genetic connectivity. Increasing fishing pressure tended to decrease potential for fished populations …

Seasonal Dynamics Of Mesodinium Rubrum In Chesapeake Bay, Matthew D. Johnson, Doane K. Stoecker, Harold G. Marshall

Biological Sciences Faculty Publications

The photosynthetic ciliate Mesodinium rubrum is a common member of coastal phytoplankton communities that is well adapted to low-light, turbid ecosystems. It supports the growth of, or competes with, harmful dinoflagellate species for cryptophyte prey, as well as being a trophic link to copepods and larval fish. We have compiled data from various sources (n = 1063), on the abundance and distribution of M. rubrum in Chesapeake Bay and its tributaries. Because M. rubrum relies on obtaining organelles from cryptophyte algae to maintain rapid growth, we also enumerated cryptophyte algae in the portion of these samples that we collected …

Population Dynamics Of Sheepshead (Archosargus Probatocephalus; Walbaum 1792) In The Chesapeake Bay Region: A Comparison To Other Areas And An Assessment Of Their Current Status, Joseph Charles Ballenger

OES Theses and Dissertations

Sheepshead recently have seen an increase in fishing pressure in Virginian waters of the Chesapeake Bay. This increase in fishing pressure has led to demands to install effective management measures to protect the fishery. However, no study regarding the population dynamics, and thus potential yield, of sheepshead has been conducted north of Cape Hatteras. We addressed the need for information regarding the population dynamics of Chesapeake Bay sheepshead by investigating their age distribution, growth rate and reproductive biology. We used this information to construct yield-per-recruit models, which local management agencies may use in the formation of scientifically based management measures. …

Evaluating Methods For Optimizing Classification Success From Otolith Tracers For Spotted Seatrout (Cynoscion Nebulosus) In The Chesapeake Bay, Stacy Kavita Beharry

OES Theses and Dissertations

Identifying the natal sources of fish is an important step in understanding its population dynamics. Adult recruits are often sourced from multiple nursery areas, with good quality locations contributing disproportionately more fish to the adult stock. Because population persistence is strongly influenced by nursery habitat, methods that correctly identify the source of recruits are necessary for effective management. Within the last decade, otolith chemistry signatures have been increasingly used as a natural marker to delineate fish from a mixture of nursery sources. Despite the widespread use of otolith trace element and stable isotope ratios as habitat markers, the statistical approaches …

Modeling The Vertical Distributions Of Downwelling Plane Irradiance And Diffuse Attenuation Coefficient In Optically Deep Waters, X. J. Pan, Richard C. Zimmerman

OES Faculty Publications

The diffuse attenuation coefficient Kᵈ is critical to understand the vertical distribution of underwater downwelling irradiance (Eᵈ). Theoretically Eᵈ is composed of the direct solar beam and the diffuse sky irradiance. Applying the statistical results from Hydrolight radiative transfer simulations, Kᵈ is expressed into a mathematical equation (named as PZ06) integrated from the contribution of direct solar beam and diffuse sky irradiance with the knowledge of sky and water conditions. The percent root mean square errors (RMSE) for the vertical distribution of Eᵈ(z) under various sky and water conditions between PZ06 and Hydrolight results are typically less than 4%. Field …

Patterns Of Larval Atlantic Croaker Ingress Into Chesapeake Bay, Usa, Jason J. Schaffler, Christian S. Reiss, Cynthia M. Jones

OES Faculty Publications

We compared ingress patterns of Atlantic croaker Micropogonias undulatus larvae into Chesapeake Bay, USA, with published ingress patterns through barrier island inlets, the accepted model for larval fish ingress. This model asserts that larvae ingress on night flood tides at the flooddominated side of the inlet and at all depths. At the Chesapeake Bay mouth and in the adjacent coastal waters, we compared the distribution of abundance, size, age, and growth rates of croaker prior to ingress, In contrast to the barrier island inlet model, croaker larvae were more abundant at depth than closer to the surface regardless of location. …

Understanding How Disease And Environment Combine To Structure Resistance In Estuarine Bivalve Populations, Eileen E. Hofmann, David Bushek, Susan E. Ford, Ximing Guo, Dale Haidvogel, Dennis Hedgecock, John M. Klinck, Coren Milbury, Diego Narvaez, Eric Powell, Yongping Wang, Zhiren Wang, Liusuo Zhang

CCPO Publications

Delaware Bay oyster (Crassostrea virginica) populations are influenced by two lethal parasites that cause Dermo and MSX diseases. As part of the US National Science Foundation Ecology of Infectious Diseases initiative, a program developed for Delaware Bay focuses on understanding how oyster population genetics and population dynamics interact with the environment and these parasites to structure he host populations, and how these interactions might modified by climate change. Laboratory and field studies undertaken during this program include identifying genes related to MSX and Dermo disease resistance, potential regions for refugia and the mechanisms that allow them to exist, …

Phytoplankton Blooms: Their Occurence And Composition Within Virginia's Tidal Tributaries, Harold G. Marshall, Todd A. Egerton

Biological Sciences Faculty Publications

Sporadic algal bloom development within a 10 year monitoring program in Virginia tidal tributaries of Chesapeake Bay is reviewed. These blooms were common events, characteristically producing a color signature to the surface water, typically short lived, occurring mainly from spring into autumn throughout different salinity regions of these rivers, and were produced primarily by dinoflagellates. The abundance threshold levels that would identify bloom status from a non-bloom presence were species specific, varied with the taxon's cell size, and ranged from ca. 10 to 10(4) cells mL(-1). Among the most consistent sporadic bloom producers were the dinoflagellates Akashiwo sanguinea, Cochlodinium …

Dinoflagellate Cysts Within Sediment Collections From The Southern Chesapeake Bay, And Tidal Regions Of The James, York, And Rappahannock Rivers, Virginia, David W. Seaborn, Harold G. Marshall

Virginia Journal of Science

The upper 2 cm of sediment core samples from 70 stations in the tidal waters of three Virginia rivers and at 23 stations in the lower Chesapeake Bay were sampled for dinoflagellate cysts. The river sediment cysts were dominated by three common bloom producing species (Heterocapsa triquetra, Scrippsiella trochoidea, and Cochlodinium polykrikoides), whereas these were in low concentration on the Chesapeake Bay sediments which contained mainly dinoflagellate cysts of neritic and oceanic taxa. The mean sediment concentrations from stations in the James, York, and Rappahannock rivers were respectively 1174.8, 536.2, and 323.6 cysts g^-1. The mean …

Factors Influencing Zooplankton Distribution In The Chesapeake And Delaware Bays, Pia Marie Paulone

Undergraduate University Honors Capstones

The Chesapeake and Delaware Bays are well known and extensively studied for their commercial value and environmental quality. There have been multiple studies based on salinity and temperature in these bays, but little is known about the influence of these factors on zooplankton distribution. Salinity has an effect on physiological processes, and, as a result, species have adapted for certain salinities. Temperature impacts both species physiology and primary productivity, which, in turn, impacts feeding rates of zooplankton. Based on previous studies on zooplankton distribution and current knowledge of physical variables, it was expected that salinity is the major variable in …

Phytoplankton Productivity In The Tidal Regions Of Four Chesapeake Bay (U.S.A.) Tributaries, Kneeland K. Nesius, Harold G. Marshall, Todd A. Egerton

Virginia Journal of Science

Monthly and annual phytoplankton productivity rates of four Virginia tidal rivers were determined based on a 12-year monitoring study that included sampling stations from tidal freshwater, oligohaline, and mesohaline regions in these rivers. The mean monthly rates and range at these locations were 5.52 (Dec.) to 175.12 (Aug.) mg C m^-3 h^-1 for tidal freshwater, 12.21 (Jan.) to 149.90 (May) mg C m^-3 h^-1 in oligohaline regions, and 16.20 (Jan.) to 151.33 (May) mg C m^-3 h^-1 for the mesohaline. The estimated mean annual 12 year productivity for the different Virginia river sites in …

Substituting Otoliths For Chemical Analyses: Does Sagitta = Lapillus?, Nathan G. Smith, Cynthia M. Jones

OES Faculty Publications

Chemical analysis of fish otoliths has become an important technique in fisheries science with widespread applications. Most research up to this point has focused predominantly on sagittal otoliths, but the underlying assumptions may also apply to lapilli. The goal of this study was to determine whether lapilli and sagittae have the same otolith chemistry and whether one can be substituted for the other for solution-based chemical analysis in wild-captured fish. We compared the stable isotope chemistry (δ13C and δ18O) of paired sagittae and lapilli of juvenile spotted seatrout Cynoscion nebulosus collected from Chesapeake Bay seagrass beds in 2002. …

Biophysical Mechanisms Of Larval Fish Ingress Into Chesapeake Bay, Jonathan A. Hare, Simon Thorrold, Harvey Walsh, Christian Reiss, Arnoldo Valle-Levinson, Cynthia Jones

OES Faculty Publications

Selective tidal stream transport is hypothesized as a dominant mechanism by which larvae of marine animals move through estuarine openings. For larvae moving from the shelf to estuarine habitats, selective tidal stream transport proposes that larvae are higher in the water column during flood tide and lower in the water column during ebb tide. Although a number of studies conclude that selective tidal stream transport is the mechanism responsible for larval ingress, few studies consider alternative mechanisms or consider passive explanations for tidal patterns in larval distributions. We examined the biophysical mechanisms responsible for larval ingress into Chesapeake Bay using …

A Review Of Phytoplankton Composition Within Chesapeake Bay And Its Tidal Estuaries, Harold G. Marshall, Lubomira Burchardt, Richard Lacouture

Biological Sciences Faculty Publications

Based on a continuous 20-year data base ofmonthly sampling in Chesapeake Bay and tidal regions of its major tributaries, 1454 phytoplankton taxa have been identified in these waters. They represent a diverse assemblage of species with a dominant diatom flora throughout the year, in addition to large seasonal representation by chlorophytes, cyanobacteria, cryptophytes and dinoflagellates. Included among this flora were 34 potential harmful or toxin producing species. The phytoplankton compositions associated with the seasonal successional patterns are discussed, in addition to characterizing the dominant floral relationships, with comparison to early composition records within the Bay. Several of the present day …

Relating Water And Otolith Chemistry In Chesapeake Bay, And Their Potential To Identify Essential Seagrass Habitats For Juveniles Of An Estuarine-Dependent Fish, Spotted Seatrout (Cynoscion Nebulosus), Emmanis Dorval

Biological Sciences Theses & Dissertations

A quantitative understanding of habitat use of estuarine-dependent fishes is critical to the conservation of their most essential habitats. Because recruitment and fitness may be influenced by the quality of juvenile habitats, developing methods to quantify habitat-specific survivorship is pivotal to such understanding. An initial step to quantify survivorship is to validate the habitat-specific natural tags contained in otoliths. To this aim I investigated the variability in the chemistry of surface waters and otoliths of juvenile spotted seatrout, Cynoscion nebulosus, in five seagrass habitats of Chesapeake Bay, namely: Potomac, Rappahannock, York, Island, and Eastern Shore. I measured Mg, Ca, …

Black Carbon In Estuarine And Coastal Ocean Dissolved Organic Matter, Antonio Mannino, H. Rodger Harvey

OES Faculty Publications

We measured black carbon (BC) in ultrafiltered, high-molecular weight dissolved organic matter (UDOM) in surface waters of Delaware Bay, Chesapeake Bay, and the adjacent Atlantic Ocean (U.S.A.) to investigate the importance of riverine and estuarine dissolved organic matter (DOM) as a source of BC to the ocean. BC was 5-72% of UDOM-C (27 ± 17%), which corresponds to 8.9 ± 6.5% of dissolved organic carbon (DOC), with higher values in the heavily urbanized midbay region of the Delaware Estuary and lower yields in the river and coastal ocean. The spatial and seasonal distributions of BC along the salinity gradient of …