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 …

Comparative Effect Of Mineral, Organic, And Mixed Sunscreens Formulations On The Life History Of A Benthic Marine Invertebrate, Jacob Anthony Fox, Courtney Lott, Araceli Rodriguez-Romero, Gloria Massamba N'Siala

Knowledge and Creativity Expo

Mineral and organic sunscreens are emerging anthropogenic pollutants in coastal marine waters and have been shown to affect marine invertebrates via genotoxicity, endocrine disruption, oxidative stress, and impacts on life-history traits, such as reduced survival, growth, and fecundity. Most experiments expose marine organisms to isolated UV filters, with fewer studies testing complete formulations, co-occurring exposure to organic and mineral sunscreens, or the modulating influence of format type on toxicity. In this experiment, we tested the impact of organic sunscreens (3% Avobenzone, 15% Homosalate, 5% Octinoxate, and 10% Octocylene) and 24% zinc oxide mineral sunscreens on the survival and fecundity of …

Predator-Prey Responses Of The Clamworm Alitta Succinea To Direct Interaction With Crabs And Chemical Cues, Shyann Mcclain, Gloria M. Massamba N'Siala

Knowledge and Creativity Expo

Predator–prey interactions in marine benthic systems can have important indirect effects mediated through environmental signaling. Predators can reveal their presence through the release of chemical cues, influencing the activity and feeding rates of other potential prey through non-consumptive effects, which may ultimately shape energy allocation and survival in targeted populations. Along the Atlantic coast of the United States, predatory crabs overlap spatially with polychaete prey such as the clamworm Alitta succinea, creating consistent predation pressure. This study will set up the experimental system needed to examine the physiological responses of clamworms to both direct and indirect predation cues under controlled …

Methane Consumption Rates By Coastal Virginia Beach Microbes, James R. Bailey Ii

Knowledge and Creativity Expo

This study measures whether microbial communities in the shallow coastal waters of Virginia Beach are capable of consuming methane in the water column. Using methane enrichment incubations and gas chromatography, we found no measurable methane oxidation of our samples over multi-day periods. These results suggest that these coastal waters may act as net sources of atmospheric methane.

Establishing Aquarium Systems And Care Protocols For Marine Invertebrates In The Department Of Biological Sciences At Odu, Magdalene R. Hamlin, Gloria Massamba N'Siala Ph.D.

Knowledge and Creativity Expo

Maintaining live animals in lab settings is useful for establishing a stock of specimens available for experimental studies without relying on continuous collection efforts. Previous aquarium systems utilized in the aquatic facility of the Department of Biological Sciences at ODU were suited for research on freshwater and marine vertebrates and were not designed for the care of marine invertebrates. This project aims to establish methods and protocols suitable for maintaining various marine invertebrates in a control laboratory setting. In the first stage of the project, the existing recirculation system and lab space will be reorganized and restructured to suit the …

The Influence Of Wind Speed On Phytoplankton Bloom Timing In Antarctica's 5 Regions, Majesti L. Cummings, Jessie S. Turners

Knowledge and Creativity Expo

Phytoplankton blooms form the foundation of the Antarctic marine food web and play a critical role in regional carbon cycling. Recent observations along the West Antarctic Peninsula indicate shifts in bloom phenology, the seasonal timing of biological events in nature, with accumulation seasons occurring later in recent decades. This study investigates how different variability in spring wind speed influences phytoplankton bloom start dates and peak dates across five ecological regions of the West Antarctic Peninsula.

Bloom timing is derived from 25 years of satellite-based chlorophyll-a observations, including annual start date and peak date. Wind speed data derived from atmospheric reanalysis …

Tracing The Journey Of Dissolved Organic Matter: From Leaf Litter Photodegradation To Microbial Processing In Tropical Streams, Samantha Nicole Sullivan

Chemistry & Biochemistry Theses & Dissertations

Dissolved organic matter (DOM) is a major reservoir of organic carbon in aquatic ecosystems and plays a central role in global carbon cycling through its transformation and remineralization to carbon dioxide (CO₂). As DOM moves from terrestrial environments into streams and rivers, its chemical composition is altered by a combination of microbial and photochemical oxidation processes that regulate both its reactivity and its persistence during transport. However, the molecular mechanisms governing these oxidative transitions, particularly in tropical ecosystems characterized by strong hydrologic seasonality and substantial inputs of plant-derived material, remain insufficiently resolved. This dissertation integrates ultrahigh-resolution mass spectrometry, optical characterization, …

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 …

Evaluation Of Ocean Lidar Enhancement Through Miniaturization And Gated Pmt-Based Range Extension, Chandler Austin Slater

OES Theses and Dissertations

Oceanographic lidar systems remotely characterize the vertical structure of the upper ocean by recording the light backscattered from a laser pulse as it propagates through the water column. Historically these systems have been constrained by limited detection ranges, often capturing only a portion of the illuminated water column, typically fading to noise around the 10% isolume. A primary constraint has been the limited dynamic range of digitizers, which inhibits the ability to resolve both intense near-field and faint far-field backscatter signals within a single acquisition. To address this, we developed a novel optical lidar system incorporating gated photomultiplier tubes (PMTs) …

The Effect Of Temperature And Salinity On Margalefidinium Polykrikoides Group Iii Va, Usa Strain Growth, Eduardo Pérez-Vega, Margaret R. Mulholland, Katherine E. Crider, Kimberly E. Powell, P. Dreux Chappell, Alexander Bochdansky

OES Faculty Publications

Margalefidinium polykrikoides is a cosmopolitan dinoflagellate that blooms in coastal waters. Despite genomic evidence that it belongs to Group III and so closely related to isolates from Puerto Rico, Malaysia, North America, and Central America, M. polykrikoides blooms in the Chesapeake Bay at warmer temperatures and lower salinities than in coastal ecosystems occupied by its closest relatives. In this study, the effect of temperature and salinity on the growth rate and total cell yield of an M. polykrikoides VA culture isolate were examined and compared with environmental observations made during M. polykrikoides blooms in the Chesapeake Bay. M. polykrikoides group …

Organic Carbon Decay Mediated By A Mesopelagic Microbial Community: The Relevance Of Carbon Pools And Broad Biochemical Composition, Noah J. Craft, Alexander B. Bochdansky

OES Faculty Publications

The mesopelagic zone is a site of strong microbially driven particle attenuation with depth and thus plays a crucial role in controlling the transfer efficiency of the ocean's biological pump. However, little quantitative information exists on the dependency of decay processes on the source material. Here we followed the decay of ¹⁴C-labeled dead particulate organic carbon (POC) and dissolved organic carbon (DOC) from three different phytoplankton species, and two incubations of live diatoms, in mesopelagic water over 3 months. Commonly used first-order kinetics failed to adequately describe the decay of organic material as rate constants varied from day to day. …

Pygoscelis Penguins Prefer Different Oceanographic And Terrestrial Habitats During The Austral Summer, Katherine L. Gallagher, Rachel Herman, Katherine Walton, Michael S. Dinniman, Heather J. Lynch

OES Faculty Publications

Pygoscelis penguins interact with both terrestrial and marine environments, especially during the austral summer when they raise their chicks. Accessible ice-free ground spaces serve as locations for penguins to build colonies and successfully raise chicks while the surrounding marine environment serves as the foraging grounds for adult birds. Penguins must be able to navigate through the waters around their colonies to forage for Antarctic krill (Euphausia superba), their primary prey during the austral summer. Krill, whose distributions are driven partially by the surrounding physics and partially by their behaviors, must also be plentiful in the waters near the …

Characterization Of Microbial Biofilms On Marine Plastics: Community Development And Density Implications For Vertical Transport Dynamics, Gregory M. Joern, Rut Pedrosa-Pàmies, Xiangtao Jiang, Zhanfei Liu, Alexander B. Bochdansky

OES Faculty Publications

Marine plastic pollution poses a significant and escalating threat to ocean ecosystems, with microbial colonization on plastics playing a critical role in determining their environmental fate. Despite the recognized importance of microbial biofilms, their composition, dynamics, and functional contributions on buoyant plastics remain poorly understood. In this study, we leveraged a novel integrative approach by simultaneously employing 16S, 18S, and ITS sequencing alongside microscopy, lipidomics, pigment analysis, adenosine triphosphate and biogenic silica quantification. This comprehensive methodology allowed for a thorough characterization of microbial growth and community dynamics on plastic debris in a mid-latitude, tidal sub-estuary. Our analyses consistently identified diatoms, …

The First Iucn Red List Of Cold-Water Corals Highlights Global Declines, Julia D. Sigwart, A. Louise Allcock, Renata Carolina Mikosz Arantes, Kelsey Archer Barnhill, Narissa Bax, Julia S. Beneti, Saskia Brix, Gudmundur Gudmundsson, Catherine S. Mcfadden, Severin A. Korfhage, Christi Linardich, Declan Morrissey, Pedro De Oliveira Nascimento, Bárbara De Moura Neves, Steinunn H. Ólafsdóttir, Stefán Ragnarsson, Kaveh Samimi-Namin, Íris Sampaio, Mark E. De Wilt

Biological Sciences Faculty Publications

The most well-known species-based conservation tool is the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. The current coverage of species in the Red List is known to under-represent benthic marine species. Cold-water corals (CWCs) are increasingly recognised as key to deep-water biodiversity and integral to protected vulnerable marine ecosystems (VMEs), but no deep-sea coral species were previously included in the Red List. We selected 22 cold-water coral species in the Northeast Atlantic, including 4 reef-forming stony corals and 18 octocorals including sea pens and gorgonians, and completed the first IUCN Red List global assessments …

Thermal Tolerance Limits Of Mesophotic Corals In American Samoa, Daniel Barshis, Veronica Z. Radice, Katherine E. Parker, Nicholas Evensen

Biological Sciences Faculty Publications

We analyzed the thermal tolerances of multiple coral species from an upper mesophotic (38–40m) and a shallow reef (5–10m) with our portable Coral Bleaching Automated Stress System (CBASS). Depth generalist Montipora grisea (deep and shallow) and depth specialists Pachyseris speciosa and Leptoseris sp. (deep only) were assayed from Leone, located on the western coast of Tutuila in American Samoa. Fragments from 10 genotypes of each species were exposed to a 17-hour thermal stress assay reaching four maximum temperatures ranging from 30–38°C under in situ light conditions (150 μmol photons m⁻² s⁻¹ under a Lee Filters “deep …

Form And Function In Mobulids: A Comparative Analysis Of Filter Morphology With Bioinspiration Applications, J. B. Teeple, S. R. Kahane-Rapport, K. E. Cohen, L. Hamann, J. A. Strother, E. W. M. Paig-Tran

Biological Sciences Faculty Publications

Mobulas (manta and devil rays) are large-scale ram filter feeders that separate planktonic food particles from large volumes of water with minimal clogging. This contrasts with most human-made filters that can suffer from problematic clogging requiring additional mechanisms for clearing blocked surfaces and maintaining performance. Prior studies have shown that mobulas employ a unique mechanism referred to as ricochet separation to filter feed, whereby captive vortices in filter pores cause particles to bounce off the filter surfaces and away from the filter pores. This mechanism enables the filtration of particles smaller than the pore size and reduced clogging. However, few …

Alternative Splicing In A Coral During Heat Stress Acclimation And Recovery, Nitin Baliga, Kathryn Stanklewicz, Jacob Valenzuela, Serdar Turkarsian, Wei-Ju Wu, Kelly Gomez-Campo, Nicolas Locatelli, Trinity Conn, Veronica Radice, Katherine Parker, Rachel Alderdice, Line Bay, Christian Voolstra, Daniel Barshis, Iliana Baums

Biological Sciences Faculty Publications

Climate change has caused drastic declines in corals. As sessile organisms, corals acclimate to environmental shifts through genome-wide changes in gene expression, epigenetic modifications, and alterations in microbiome composition. However, alternative splicing (AS), a conserved mechanism of stress response in many organisms, has been under-explored in corals. Using short-term acute thermal stress assays, we investigated patterns of AS in the scleractinian coral Acropora cervicornis during response to low (33°C), medium (35°C), and high (37°C) heat stress and subsequent overnight recovery. Our findings demonstrate reproducible dynamic shifts in AS of at least 40 percent of all genes during response to heat …

Analyzing Microbial Communities In Porites Astreoides, Sanaa Caldwell, Katie Parker, Daniel Barshis

Biological Sciences Faculty Publications

Coral reefs are vital marine ecosystems that support many different species and ecosystem services through protecting coastlines from storms and erosion, providing raw materials for medication, and facilitating diversity amongst marine species. Anthropogenic climate change is causing ocean temperatures to exceed the range of coral thermal tolerance resulting in more coral bleaching events globally. However, some corals have the capacity to withstand high temperatures through different thermal tolerance strategies. A balanced microbial community plays a critical role in coral health and recent studies have indicated that a balanced microbiome is associated with temperature-stress tolerant corals. Yet, there is a severe …

A Multispecies, Multisite Assessment Of Coral Thermal Tolerances In American Samoa, Using Acute Heat Stress Assays, Ponchanok Weeriyanun, Nicolas R. Evensen, Katherine E. Parker, Veronica Z. Radice, Daniel J. Barshis

Biological Sciences Faculty Publications

Reef-building corals are being impacted by increasing seawater temperatures, with marine heatwaves leading to mass bleaching events and extensive mortality. However, corals can display variation in thermal tolerance, both within and among species. In this study, we sampled four coral species (Acropora hyacinthus, Montipora grisea, Pocillopora verrucosa, and Porites lobata) from two sites on Tutuila, American Samoa, with contrasting environmental regimes but similar Maximum Monthly Means (MMM). Coral fragments were subjected to short-term acute heat stress experiments using the Coral Bleaching Automated Stress System (CBASS). PAM Fluorometry was used to measure the symbiont’s effective quantum yield (Fv/Fm) following heat stress …

Mobula, Bioinspiration, Filter Feeding, Form And Function, J. B. Teeple, S. R. Kahane-Rapport, K. E. Cohen, L. Hamann, J. A. Strother, E. W.M. Paig-Tran

Biological Sciences Faculty Publications

Mobulas (manta and devil rays) are large-scale ram filter feeders that separate planktonic food particles from large volumes of water with minimal clogging. This contrasts with most human-made filters that can suffer from problematic clogging requiring additional mechanisms for clearing blocked surfaces and maintaining performance. Prior studies have shown that mobulas employ a unique mechanism referred to as ricochet separation to filter feed, whereby captive vortices in filter pores cause particles to bounce off the filter surfaces and away from the filter pores. This mechanism enables the filtration of particles smaller than the pore size and reduced clogging. However, few …

Assemblage Structure Of Large Carnivorous Coral Reef Fishes At Shallow And Mesophotic Depths In Two Of The Largest And Most Isolated Marine Protected Areas In The Philippines, Rene A. Abesamis, Mikaela L. Salvador, Ryan Murray, Kymry Delijero, Segundo F. Conales, Jean T. Utzurrum, Christopher E. Bird, David T. Gauthier

Biological Sciences Faculty Publications

Overfishing remains a threat to coral reef fishes globally, with large carnivores often the most vulnerable. Marine protected areas (MPAs) can restore fish populations and biodiversity, but their impact has been understudied in mesophotic coral ecosystems (MCEs – extensions of shallow reefs from 30 to 150 m). We analyzed baited remote underwater videos recorded in 2016 to investigate the assemblage structure of large carnivorous fishes at shallow (4–12 m) and mesophotic (45–96 m) depths in two of the largest and most isolated MPAs in the Philippines: Tubbataha Reefs Natural Park (TRNP), a fully no-take MPA enacted in 1988; and Cagayancillo, …

First Reference Genomes For Two Mesophotic Reef Building Coral Species: Leptoseris Cf. Scabra And Montipora Cf. Grisea, Veronica Z. Radice, Johanna C. Gijsbers, Silvia Vimercati, Daniel J. Barshis

Biological Sciences Faculty Publications

Coral mortality is occurring worldwide at an alarming rate. Despite the immense and underestimated biodiversity of reef-building corals, very few genomes are available. Further, almost all genomic resources originate from shallow water corals even though photosynthetic, symbiotic corals occur at mesophotic depths deeper than 30 m and even >100 m. We present annotated, de novo genomes for two mesophotic, scleractinian (reef-building) corals Montipora cf. grisea and Leptoseris cf. scabra from American Sāmoa, the latter being the first genome for the widespread genus Leptoseris. We used PacBio continuous long reads and Omni-C data to assemble chromosome-level reference genomes. For Montipora …

Squid Paralarvae Turn With High Agility Using Jets Near The Reynolds Number Threshold For Viscous Domination, Ian K. Bartol, Alissa M. Ganley, Paul S. Krueger, Joseph T. Thompson

Biological Sciences Faculty Publications

Turning is critical for survival in the ocean, as marine animals need to maneuver to capture prey, elude predators, and navigate complex environments. While prior research has focused on turning performance of adult swimmers, less is known about early ontogenetic stages that locomote within lower Reynolds number (Re) regimes, especially young jetters. To evaluate squid paralarval turning proficiency and the role of the pulsed jet in maneuvers, recently hatched longfin squid Doryteuthis pealeii swimming in a viewing chamber were studied using digital particle image velocimetry and kinematic motion analyses. Paralarvae exhibited a wide repertoire of turning behaviors, including those performed …

Seasonal Variability Of Surface Ocean Carbon Uptake And Chlorophyll-A Concentration In The West Antarctic Peninsula Over Two Decades, Jessica S. Turner, David R. Munro, Amanda Fay, Sharon Stammerjohn, Heather Kim, Oscar Schofield, Heidi Dierssen

OES Faculty Publications

The Southern Ocean plays a vital role in global CO₂ uptake, but the magnitude and even the sign of the flux remain uncertain, and the influence of phytoplankton phenology is underexplored. This study focuses on the West Antarctic Peninsula, a region experiencing rapid climate change, to examine shifts in seasonal carbon uptake. Using 20 years of in situ air-sea CO₂ flux and satellite-derived Chlorophyll-a, we observe that the seasonal cycles of both air-sea CO₂ flux and Chlorophyll-a intensify poleward. The amplitude of the seasonal cycle of the non-thermal component of surface ocean pCO₂ increases with increasing latitude, while the amplitude …

Salt: A Tribute To Ghana's Fishers, Vanessa F. Jaiteh

Green Humanities: A Journal of Ecological Thought in Literature, Philosophy & the Arts

This poem is a tribute to my fieldwork on fisher safety, labour abuses and human rights violations in Ghana’s fisheries.

Time Series Modeling To Ascertain Age In Fisheries Management, Kathleen Sue Kirch

OES Theses and Dissertations

The ability to assign accurate ages of fish is important to fisheries management. Accurate ageing allows for the most reliable age-based models to be used to support sustainability and maximize economic benefit. Structures used to age include bones, scales, and most commonly ear bones (otoliths). Assigning age relies on validating putative annual marks by evaluating accretional material laid down in patterns in fish otoliths, typically by marginal increment analysis. These patterns often take the shape of a sawtooth wave with an abrupt drop in accretion yearly to form an annual band and are typically validated qualitatively. Researchers have shown keen …

Maneuverability Of Cuttlefish And Squid: An Integrated Kinematic And Hydrodynamic Analysis, Alissa Marie Ganley

Biological Sciences Theses & Dissertations

Turning is important for life underwater, playing roles in predator avoidance, prey capture, locomotion, and communication. While turning abilities have been explored in many taxa, little is known about maneuverability of cephalopods, such as cuttlefishes and squids. The objectives of this dissertation include: (1) quantifying the turning abilities of cuttlefish hatchlings and determining whether there are species-specific differences; (2) examining the turning capabilities of adult cuttlefishes, with the goal of comparing adult performance with that of conspecific hatchlings; and (3) quantifying how adult neritic squids perform turns to provide a broader context of maneuvering strategies in cephalopods. To investigate turning, …

Nitrogen Uptake Rates And Phytoplankton Composition Across Contrasting North Atlantic Ocean Coastal Regimes North And South Of Cape Hatteras, Yifan Zhu, Margaret R. Mulholland, Peter W. Bernhardt, Aimee Renee Neeley, Brittany Widner, Alfonso Macías Tapia, Michael E. Echevarria

OES Faculty Publications

Understanding nitrogen (N) uptake rates respect to nutrient availability and the biogeography of phytoplankton communities is crucial for untangling the complexities of marine ecosystems and the physical, biological, and chemical forces shaping them. In the summer of 2016, we conducted measurements of bulk microbial uptake rates for six ¹⁵N-labeled substrates: nitrate, nitrite, ammonium, urea, cyanate, and dissolve free amino acids across distinct marine provinces, including the continental shelf of the Mid-and South Atlantic Bights (MAB and SAB), the Slope Sea, and the Gulf Stream, marking the first instance of simultaneously measuring six different N uptake rates in this dynamic region. …

Diel Vertical Migration Rates Of The Dinoflagellate Species Margalefidinium Polykrikoides In A Lower Chesapeake Bay Tributary, S. Clayton, Jacqueline B. Chrabot, Michael Echevarria, Leah Gibala-Smith, Kathryn Mogatas, Peter Bernhardt, Margaret R. Mulholland

OES Faculty Publications

Margalefidinium polykrikoides is a mixotrophic dinoflagellate harmful algal bloom (HAB) species that blooms annually in the lower Chesapeake Bay. M. polykrikoides undertakes a diel vertical migration (DVM) which may give it a competitive advantage over purely phototrophic organisms who cannot access deeper nutrient pools and allow it to form large toxic blooms. Laboratory-based estimates of M. polykrikoides’ DVM rates suggest that it is one of the fastest known dinoflagellate swimmers and understanding this behavior is likely important for modeling and predicting M. polykrikoides blooms. However, to date, no field-derived estimates of M. polykrikoides’ DVM rates have been made in the …

Contrasting Nitrogen Dynamics Across The Mid-Atlantic Bight Shelfbreak Front: Insights From Nitrate Dual Isotopes And Nitrifier Gene Abundance, Yifan Zhu, Margaret R. Mulholland, Corday R. Selden, Dennis J. Mcgillicuddy Jr., Josie Mottram, P. Dreux Chappell, Weifang Gordon Zhang, Julie Granger, Katherine E. Crider, Meredith G. Meyer, Peter W. Bernhardt, Hilde Oliver, Sophie Clayton

OES Faculty Publications

Observations and model studies suggest that front dynamics can enhance phytoplankton productivity. This study tested whether frontal systems also increase the abundance of nitrifying microbes and nitrogen recycling during repeat sampling transects across the Mid‐Atlantic Bight shelfbreak in July 2019. We measured ammonium concentrations, nitrate dual isotopes (δ¹⁵N, δ¹⁸O), and ammonia monooxygenase subunit A (amoA) genes of ammonia‐oxidizing archaea (AOA) and bacteria (AOB). In subsurface shelf waters, ammonium concentrations exceeded 2 μmol L⁻¹, due to a temporary imbalance in regeneration from sinking particles and subsequent nitrification. The inverse correlation between nitrate δ^{15 …}