Marine Biology Commons^™

Fecal Pellet Production By North Atlantic Zooplankton, Michael Gibson

Undergraduate Honors Theses

Fecal pellet carbon (FPC) production by zooplankton is a significant component of the ocean’s biological carbon pump: the suite of biological processes that mediate export of carbon to the deep ocean, ultimately leading to the sequestration of atmospheric carbon dioxide in the ocean. In this study, mesozooplankton (zooplankton 0.2 mm to ~2 cm) were collected from the epipelagic zone in the temperate North Atlantic Ocean during day and night in May 2021. Zooplankton were live separated into five size fractions and incubated on board ship in natural surface seawater to measure fecal pellet production rate of the mixed mesozooplankton community. …

Carrying Capacity Of Cultured Bivalves In Cherrystone Inlet, Va, And The Implications Of Spatial Distribution And Environmental Change, Sophia Chirico

Undergraduate Honors Theses

Aquaculture is a growing industry internationally. In the United States, aquaculture of bivalves occurs throughout the Chesapeake Bay. Cherrystone Inlet, a tidal inlet on the Virginia Eastern Shore, is the location of intensive hard clam culture, and recently oyster aquaculture has become common there as well. Given the intensive culture in Cherrystone and similar systems in the Chesapeake, it is important to understand the carrying capacity of the respective bivalves and how they can be grown together. Carrying capacity is defined here as the largest population of individuals that can be supported that allows individuals to reach a harvestable size …

Intertidal Zonation Of Hemichordates In Soft Sediments, Kharis R. Schrage, Juselyn D. Tupik, Jonathan D. Allen

Arts & Sciences Articles

Intertidal zonation of organisms is well studied on rocky shores but less so in soft sediment communities. On rocky shores, communities are two dimensional, with biotic factors such as competition and predation setting the lower bound of a zone, whereas abiotic factors such as desiccation set the upper bound. In soft sediment communities, these patterns persist, but with a dynamic three-dimensional ecosystem occupied by mobile infaunal organisms, zonation can be more difficult to quantify and detect. Hemichordate worms, however, deposit fecal casts at the surface, which can be easily identified and counted, making them a potential model system for identifying …

A Rapid Phenotype Change In The Pathogen Perkinsus Marinus Was Associated With A Historically Significant Marine Disease Emergence In The Eastern Oyster, Ryan Carnegie, Susan E. Ford, Rita K. Crockett, Peter R. Kingsley-Smith, Lydia M. Bienlien, Lucia S.L. Safi, Laura A. Whitefleet-Smith, Eugene M. Burreson

VIMS Articles

The protozoan parasite Perkinsus marinus, which causes dermo disease in Crassostrea virginica, is one of the most ecologically important and economically destructive marine pathogens. The rapid and persistent intensification of dermo in the USA in the 1980s has long been enigmatic. Attributed originally to the effects of multi-year drought, climatic factors fail to fully explain the geographic extent of dermo’s intensification or the persistence of its intensified activity. Here we show that emergence of a unique, hypervirulent P. marinus phenotype was associated with the increase in prevalence and intensity of this disease and associated mortality. Retrospective histopathology of …

Changes In Plant Communities Of Low-Salinity Tidal Marshes In Response To Sea-Level Riselow-Salinity Tidal Marshes In Response To Sea-Level Rise, Abbey Humphreys, Adrianna L. Gorsky, Donna M. Bilkovic, Randolph M. Chambers

VIMS Articles

As sea-level rises, low-salinity tidal marshes experience greater flooding with more saline water. In the Chesapeake Bay estuary, we compared the 1980 and 2014 tidal marsh inventories (TMIs) of plant communities from James City County, Virginia, USA, with respect to the spatial distribution of two species—the invasive reed Phragmites australis and native salt marsh grass Spartina alterniflora–plus overall species richness. Since the 1980 TMI, the total area of low-salinity tidal marshes in which P. australis occurred increased from 0.46 km² to 6.30 km² in 2014. Between TMIs, however, the total area of low-salinity marshes occupied by …

Asymmetric Root Distributions Reveal Press–Pulse Responses In Retreating Coastal Forests, Tyler C. Messerschmidt, Amy K. Langston, Matthew L. Kirwan

VIMS Articles

The impacts of climate change on ecosystems are manifested in how organisms respond to episodic and continuous stressors. The conversion of coastal forests to salt marshes represents a prominent example of ecosystem state change, driven by the continuous stress of sea-level rise (press), and episodic storms (pulse). Here, we measured the rooting dimension and fall direction of 143 windthrown eastern red cedar (Juniperus virginiana) trees in a rapidly retreating coastal forest in Chesapeake Bay (USA). We found that tree roots were distributed asymmetrically away from the leading edge of soil salinization and towards freshwater sources. The length, number, …

Climate Drives The Geography Of Marine Consumption By Changing Predator Communities, M. A. Whalen, R.D. B. Whippo, J. J. Stachowicz, (...), Paige G. Ross, Et Al

VIMS Articles

The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, …

Ecological Associations Of Littoraria Irrorata With Spartina Cynosuroides And Spartina Alterniflora, Caroline Mackenzie Failon, Serina Sebilian Wittyngham, David S. Johnson

VIMS Articles

It is well-documented that marsh periwinkles (Littoraria irrorata) consume and inhabit smooth cordgrass (Spartina alterniflora), but their interactions with big cordgrass (Spartina cynosuroides) remain unknown. Plant communities in mesohaline marshes will change as sea-level rise shifts species from salt-intolerant (e.g., S. cynosuroides) plants to salt-tolerant (e.g., S. alterniflora) ones. Therefore, understanding how L. irrorata interacts with different habitats provides insight into this species’ generalist nature and allows us to predict the potential impacts of changing plant communities on L. irrorata. We show, for the first time, that L. irrorata inhabits, climbs, …

Ecological Monitoring Program At Vims Esl - Annual Report 2018-2019, Paige G. Ross, Richard A. Snyder

Reports

An Ecological Monitoring Program (EMP) has been established at the Virginia Institute of Marine Science Eastern Shore Laboratory (VIMS ESL) for the coastal environment near the lab. The goals of the initiative are to 1) provide status and trends information to scientists who study and regulators who manage Virginia’s marine resources, 2) provide a scientific context for scientists’ research and grant proposals 3) provide pedagogical enrichment to educators for their classes, and 4) build capacity in staff expertise and training of interns and students at VIMS ESL.

The program formalizes and standardizes data collection for a long-term status and trends …

Positive Ecological Interactions And The Success Of Seagrass Restoration, Stephanie R. Valdez, Y. Stacy Zhang, Tjisse Van Der Heide, Mathew A. Vanderklift, Flavia Tarquinio, R J. Orth, Brian R. Silliman

VIMS Articles

Seagrasses provide multiple ecosystem services including nursery habitat, improved water quality, coastal protection, and carbon sequestration. However, seagrasses are in crisis as global coverage is declining at an accelerating rate. With increased focus on ecological restoration as a conservation strategy, methods that enhance restoration success need to be explored. Decades of work in coastal plant ecosystems, including seagrasses, has shown that positive species relationships and feedbacks are critical for ecosystem stability, expansion, and recovery from disturbance. We reviewed the restoration literature on seagrasses and found few studies have tested for the beneficial effects of including positive species interactions in seagrass …

Monitoring The Abundance Of American Shad And River Herring In Virginia's Rivers - 2019 Annual Report, Eric J. Hilton, Robert Latour, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee

Reports

This report describes the results of the twenty-second year of a continuing study to estimate the relative abundance and assess the status of American shad (Alosa sapidissima) stocks in Virginia by monitoring the spawning runs in the James, York and Rappahannock rivers in spring 2019, evaluating hatchery programs, and contributing to coast-wide assessments (ASMFC 2007). We also report on two fishery-independent monitoring programs using anchor gillnets in the Rappahannock River (year 2) and the Chickahominy River (year 5; a major tributary of the James River), to determine relative abundance and stock structure for the adult spawning run of river herring …

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 …

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 …

Monitoring The Abundance Of American Shad And River Herring In Virginia's Rivers - 2018 Annual Report, Eric J. Hilton, Robert Latour, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee

Reports

This report describes the results of the twenty-first year of a continuing study to estimate the relative abundance and assess the status of American shad (Alosa sapidissima) stocks in Virginia by monitoring the spawning runs in the James, York and Rappahannock rivers in spring 2018, evaluating hatchery programs, and contributing to coast-wide assessments (ASMFC 2007). We also report on two fishery-independent monitoring programs using anchor gillnets in the Rappahannock River (year 1) and the Chickahominy River (year 4; a major tributary of the James River), to determine relative abundance and stock structure for the adult spawning run of river herring …

Unexplored Aspects Of The Biotic Filter To Seedling Recruitment In Aquatic Environments, Andrew James Johnson

Dissertations, Theses, and Masters Projects

Sexual reproduction provides submerged aquatic vegetation (SAV) populations unique opportunities for dispersal, genetic mixing, and resilience in the event of catastrophic population declines. Relative to asexual reproduction, sexual reproduction is a risky resource investment and can have a lower probability of success. A wide variety of abiotic and biotic interactions common in both terrestrial and aquatic environments can lead to significant mortality of seeds and seedlings. The goal of this dissertation is to explore the diversity of biological interactions that influence seed and seedling survival in SAV that drive the population dynamics and restoration success of SAV species. A combination …

Satellites, Seagrass, And Blue Crabs: Understanding Inter-Annual Fluctuations And Linkages In The York River, Kristen Bachand

Dissertations, Theses, and Masters Projects

To protect and manage ecosystems over large spatial scales, repeated mapping with remote sensing, such as aerial photography, is valuable, but several potential problems need to be overcome to generate accurate maps. For instance, to monitor submerged aquatic vegetation (SAV), such as seagrass, satellite imagery must often capture seasonal and interannual variation as well as disturbances. We used a model system, SAV and the blue crab Callinectes sapidus in the lower Chesapeake Bay, to examine (i) if Planet Lab (PL) satellite imagery can be used to accurately estimate SAV coverage by comparing PL images coincident with those of the VIMS …

Monitoring The Abundance Of American Shad And River Herring In Virginia's Rivers - 2017 Annual Report, Eric J. Hilton, Rob Latour, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee

Reports

This report describes the results of the twentieth year of a continuing study to estimate the relative abundance and assess the status of American shad (Alosa sapidissima) stocks in Virginia by monitoring the spawning runs in the James, York and Rappahannock rivers in spring 2017, evaluating hatchery programs, and contributing to coast-wide assessments (ASMFC 2007). We also report on two fishery-independent monitoring programs, one using staked gillnets in the Rappahannock River (year 2) and the other using anchor gillnets in the Chickahominy River (year 3; a major tributary of the James River),to determine relative abundance and stock structure for the …

Allometry Of Individual Reproduction And Defense In Eusocial Colonies: A Comparative Approach To Trade-Offs In Social Sponge- Dwelling Synalpheus Shrimps, Sarah L. Bornbusch, Jonathan S. Lefcheck, J. Emmett Duffy

VIMS Articles

Eusociality, one of the most complex forms of social organization, is thought to have evolved in several animal clades in response to competition for resources and reproductive opportunities. Several species of snapping shrimp in the genus Synalpheus, the only marine organisms known to exhibit eusociality, form colonies characterized by high reproductive skew, and aggressive territoriality coupled with cooperative defense. In eusocial Synalpheus colonies, individual reproduction is limited to female 'queens', whose fecundity dictates colony growth. Given that individual reproduction and defense are both energetically costly, individual and colony fitness likely depend on the optimal allocation of resources by these reproducing …

Monitoring The Abundance Of American Shad And River Herring In Virginia's Rivers - 2016 Annual Report, Eric J. Hilton, Robert Latour, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee

Reports

This report describes the results of the nineteenth year of a continuing study to estimate the relative abundance and assess the status of American shad (Alosa sapidissima) stocks in Virginia by monitoring the spawning runs in the James, York and Rappahannock rivers in spring 2016, evaluating hatchery programs, and contributing to coast-wide assessments (ASMFC 2007). We also report on a new fishery-independent monitoring program using staked gillnets to determine relative abundance and stock structure for the adult spawning run of river herring (A. pseudoharengus, and A. aestivalis) in the Rappahannock River. Data are also reported from two separate fishery-independent monitoring …

Spatiotemporal Abundance Patterns And Ecological Drivers Of A Nearshore U.S. Atlantic Fish And Invertebrate Assemblage, Mark A. Stratton

Dissertations, Theses, and Masters Projects

Taking an ecosystem approach to fisheries requires the consideration of relevant ecological processes within research and assessment frameworks. Processes affecting ecosystem productivity can be categorized as biophysical (climate variability, primary production), exploitative (fishing), or trophodynamic (food web interactions). This dissertation incorporates these three governing processes to characterize spatiotemporal diversity and population abundance trends for multiple demersal fish and invertebrate species that inhabit the nearshore zone (15-30 ft. depth) along portions of the U.S. Atlantic east coast.

Two large marine ecosystems (LMEs) encompass the U.S. East coast – the Southeast and Northeast U.S. Continental Shelf LMEs. The level of connectivity within …

Integrating Empirical Data And Ocean Drift Models To Better Understand Sea Turtle Strandings In Virginia, Bianca Silva Santos

Dissertations, Theses, and Masters Projects

Hundreds of stranded turtles wash up deceased on Virginia’s coastline each year, yet the causes of most stranding events are poorly understood. In this thesis, a carcass drift model was developed for the Chesapeake Bay, Virginia, to predict likely locations of mortality from coastal sea turtle stranding records. First, field studies were carried out to better parameterize the drift characteristics of buoyant sea turtle carcasses, namely, probable oceanic drift times and the impact of direct wind forcing on carcass drift. Based on the duration that tethered, free-floating turtle carcasses were buoyant, we determined that oceanic drift duration of turtle carcasses …

Associated Dataset: Climate Change Impacts On Southern Ross Sea Phytoplankton Composition, Productivity And Export, Daniel E. Kaufman, Marjorie A.M. Friedrichs, Walker O. Smith Jr., Eileen E. Hofmann, Michael S. Dinniman, John C.P. Hemmings

Data

This dataset includes data used in the publication Kaufman et al., 2017, JGR-Oceans, which investigates how these climatic changes in the Ross Sea, Antarctica, may alter phytoplankton composition, primary productivity and export. A one-dimensional version of the Model of Ecosystem Dynamics, nutrient Utilisation, Sequestration and Acidification was adapted for use in the Ross Sea (MEDUSA-RS). Glider measurements were used to force MEDUSA-RS, which includes diatoms and both solitary and colonial forms of Phaeocystis antarctica. Model performance was evaluated with glider observations, and experiments were conducted using projections of physical drivers for mid- and late-21st century. Additional scenarios examined the …

Juvenile Blue Crab (Callinectes Sapidus) Response To Altered Nursery Habitat, Megan Wood

Dissertations, Theses, and Masters Projects

Habitats of Chesapeake Bay have been altered due to anthropogenic impacts and climate change. Due to these human disturbances, seagrasses have been extirpated from many areas in lower Chesapeake Bay and persisting beds face future losses as water temperatures continue to rise. Further loss of seagrass habitat will negatively impact juvenile blue crabs (Callinectes sapidus) that use seagrass beds as nursery grounds. Habitat degradation allows for more successful introductions of exotic species, and the communities formed from the mixing of native and exotic species are known as emerging ecosystems. Gracilaria vermiculophylla, an exotic macroalga, may be an emerging nursery habitat …

Differential Effects Of Bivalves On Sediment Nitrogen Cycling In A Shallow Coastal Bay, Ashley Smyth, Anna E. Murphy, Iris C. Anderson, Bk Song

VIMS Articles

In coastal ecosystems, suspension-feeding bivalves can remove nitrogen though uptake and assimilation or enhanced denitrification. Bivalves may also retain nitrogen through increased mineralization and dissimilatory nitrate reduction to ammonium (DNRA). This study investigated the effects of oyster reefs and clam aquaculture on denitrification, DNRA, and nutrient fluxes (NOx, NH4 6 +, O2). Core incubations were conducted seasonally on sediments adjacent to restored oyster reefs (Crassostrea virginica), clam aquaculture beds (Mercenaria mercenaria) which contained live clams, and bare sediments from Smith Island Bay, Virginia, USA. Denitrification was significantly higher at oyster reef sediments and clam aquaculture site than bare sediment in …

Nitrogen Isotope Fractionation And Toxin Production During The Uptake Of Micromolar Concentrations Of Nitrate, Ammonium, And Urea By A Marine Dinoflagellate, Christen Taylor Armstrong

Dissertations, Theses, and Masters Projects

Despite an increased global interest in harmful algal bloom (HAB) species and eutrophication, the relationship between nutrient sources and changes in species composition or toxicity remains unclear. Stable isotopes are routinely used to identify and track nitrogen (N) sources to water bodies, as sources can be differentiated based on stable isotope values. While literature is available describing N fractionation by diatoms and coccolithophores, data are greatly lacking regarding isotope fractionation by dinoflagellates. Here we investigate the fractionation of nitrogen isotopes by saxitoxin-producing Alexandrium fundyense, to validate the use of the δ15N of particulate organic matter and identify the nitrogen source …

Ecosystem Services Of Restored Oyster Reefs In A Chesapeake Bay Tributary: Abundance And Foraging Of Estuarine Fishes, Bruce William Pfirrmann

Dissertations, Theses, and Masters Projects

Oyster reef restoration may enhance the production of ecologically or economically important fish species, an ecosystem service, by providing refuge and foraging habitat. Predicting the effects of oyster habitat restoration on fisheries production in Chesapeake Bay requires a better understanding of fish habitat use, trophic dynamics, and the processes leading to production on a habitat-scale. The objective of this thesis was to evaluate the influence of restored subtidal oyster reefs on the abundance and foraging patterns of mobile estuarine fishes. Specifically, I compared the 1) abundance, 2) stomach fullness, 3) diet composition, and 4) daily consumption rate of fishes collected …

Population Size And Survival Rates Of Blue Catfish In Chesapeake Bay Tributaries, Mary C. Fabrizio, Troy D. Tuckey, Robert J. Latour, Gary C. White, Alicia J. Norris, Mary Groves

Reports

This report comprises two studies conducted from 2012 to 2015 to estimate population size, survival rates, and movements of invasive blue catfish in Chesapeake Bay tributaries. The first study of population-size and survival was conducted in the James River, VA (Population Size and Survival Rates of Invasive Blue Catfish in Tidal Waters of the James River Subestuary). The second study on movement and survival of blue catfish was conducted in the Potomac River, the natural boundary between Maryland and Virginia (Movement Patterns and Survival Rate of Blue Catfish in a Non-Native Habitat Estimated with a Tagging Study). The Executive Summary …

The Demographic Consequences Of Growing Older And Bigger In Oyster Populations, Jl Moore, Rom Lipcius, B Puckettt, Sj Schrieber

VIMS Articles

Structured population models, particularly size-or age-structured, have a long history of informing conservation and natural resource management. While size is often easier to measure than age and is the focus of many management strategies, age-structure can have important effects on population dynamics that are not captured in size-only models. However, relatively few studies have included the simultaneous effects of both age-and size-structure. To better understand how population structure, particularly that of age and size, impacts restoration and management decisions, we developed and compared a size-structured integral projection model (IPM) and an age-and size-structured IPM, using a population of Crassostrea gigas …

Modeling Phytoplankton Community Response To Nutrient Loading And Climate Change In A Shallow Temperate Estuary, Sara Aimee Blachman

Dissertations, Theses, and Masters Projects

Phytoplankton account for at least half of all primary production in estuarine waters and are at the center of biogeochemical cycles and material budgets. Environmental managers use water column chlorophyll-a (chl-a) concentrations as a basic water quality indictor, as the problems of eutrophication and hypoxia are intrinsically linked to excessive phytoplankton growth. Evidence suggests that the distribution and frequency of harmful algal blooms may be increasing worldwide. For the most part, phytoplankton communities follow a standard seasonal pattern, with specific groups dominating the assemblage during the time of year when environmental conditions correspond to their requisites for growth. However, climate …

Zooplankton Community Composition And Grazing In The Amazon River Plume And Western Tropical North Atlantic Ocean, Brandon J. Conroy

Dissertations, Theses, and Masters Projects

Large river plumes and frontal zones are important physical features influencing plankton distribution in the marine environment. In the western tropical North Atlantic Ocean (WTNA) the Amazon River plume may extend over an area reaching 1.5 x 106 km2. The freshwater plume creates a low-density lens in the surface 25m and supplies silicon and phosphorus to the WTNA. These physical and chemical gradients create an ideal environment for large-scale blooms of diatom diazotroph associations (DDAs), a symbiotic relationship between nitrogen-fixing cyanobacteria and chain-forming diatoms. While the physical and chemical properties of the plume with regard to influences on phytoplankton have …