Oceanography and Atmospheric Sciences and Meteorology Commons^™

What Controls Ice Shelf Isotopic Variability? Local And Global Processes Preserved Within Ice Cores Across The Larsen C Ice Shelf, Antarctica, Orion Laurene Schomber

USF Tampa Graduate Theses and Dissertations

The Antarctic Peninsula (AP) is one of the foremost indicators of anthropogenic global warming as it interacts with both atmospheric and oceanic processes. Although ice shelves across the AP have undergone increased rates of disintegration over the last 30 years, limited in-situ measurements have been investigated. Assessment of three short (~30 m) firn cores (J108, J208, and J409) across the Larsen C ice shelf (LCIS) provide insight into local, regional, and global processes. Average core densities and isotopic variability (δ¹⁸O and δ²H) fall within expected ranges for all cores, indicating signal preservation through firn. However, isotopic maxima in J108 and …

Mapping Seagrass Extent Using Sentinel-2 Satellite Imagery: A Case Study In Salt River Bay, United States Virgin Islands, Chelsea O. Bryant

USF Tampa Graduate Theses and Dissertations

Seagrass beds provide important services in many coastal ecosystems. They provide habitat and food for a wide range of marine species, stabilize sediments, and prevent coastal erosion. These services support local fisheries and tourism-driven economies. Yet, seagrass ecosystems are threatened by changes in water quality, sedimentation, and other stressors. This study investigated the interannual variability in seagrass extent in Salt River Bay, United States Virgin Islands (USVI), from 2018 to 2024. The goals were to better understand temporal dynamics in seagrass extent and evaluate the influence of turbidity as a driver of seagrass health and distribution. The overarching research question …

Concentration And Composition Of Organic Contaminants In Blackfin Tuna, Yellowfin Tuna, And The Common Clubhook Squid In The Western Gulf Of Mexico, Lisa Rose-Mann

USF Tampa Graduate Theses and Dissertations

Cephalopods are an important component of pelagic food webs. They play ecological roles not only as predators but also as prey. However, their role as prey in the trophic transfer of organic contaminants to apex predators such as tunas in the Gulf of Mexico (GoM) is not well known. To investigate the importance of cephalopods in tuna diets, stomach samples were collected in February 2020 from tunas caught by rod and reel aboard the F/V Gulf Eagle near two large offshore floating oil/gas platforms in the northwestern GoM. Cephalopod samples were obtained from gut content analysis of 41 tunas caught …

Isotopic Fingerprints Of The Coastal Margins: Tracing Dissolved Iron Sources From Land To Sea, Hannah R. Hunt

USF Tampa Graduate Theses and Dissertations

Dissolved iron (dFe) is an essential micronutrient for sustaining life in the surface ocean. Nearly four decades of research dedicated to understanding sources, cycling and biogeochemical modifications of Fe sources in the global oceans has generated a significant body of research supporting the idea that the concentration of Fe in the surface ocean exerts significant controls on primary production and carbon uptake in the surface ocean. Creation of the GEOTRACES program greatly increased the spatial and temporal resolution of high-quality trace element and trace element isotope data revealing new insights into the global Fe cycle, especially through the use of …

Characterizing West Florida Shelf Reef Fish Communities Using A Scientific Echosounder, Edmund A. Hughes

USF Tampa Graduate Theses and Dissertations

The advancement and application of non-invasive fisheries survey technologies, such as the scientific echosounder, have significantly enhanced our understanding of fish populations and their habitats, more recently in regions where traditional sampling methods are limited, such as complex reef habitats. This research, conducted as part of the Continental Shelf Characterization, Assessment, and Mapping Project (C-SCAMP) on the West Florida Shelf, leverages acoustic and visual technologies to investigate the distribution of fish densities, fish target strength and length relationships, and the relationship between seafloor topography and fish biomass distribution.

The first study compared reef fish densities estimated from near-concurrent acoustic (Simrad …

Artificial Reefs As Management Tools, Tiff Raetzel

USF Tampa Graduate Theses and Dissertations

Artificial reefs are attractive tools for fisheries management and reef conservation, as they can host large fish biomasses, including fisheries-important species, and they may supplement natural recruitment. Prior studies have established that artificial and natural reefs differ in habitat complexity and host both taxonomically and functionally distinct assemblages. These differences may impact how the reef types respond to environmental disturbance because ecosystem stability is dependent upon habitat structure, species composition, and trophic interactions. A question of management importance is whether artificial reefs host a less- or more-sensitive suite of species than natural reefs, and whether the assemblage is conducive to …

Hurricane Evacuation: Navigating Uncertainty During Covid 19 And With Existing Communication Scales, And Considering Public And Expert Perception Of Alternative Scales, Leilani D. Paxton

USF Tampa Graduate Theses and Dissertations

This dissertation investigates the effectiveness of current hurricane warning products and communication strategies, exploring factors influencing public perception of risk and decision-making during evacuations. The study employs a mixed-methods approach, combining survey data, focus group discussions, and interviews with meteorologists and emergency managers. The first paper examines the impact of the COVID-19 pandemic on hurricane risk perception and evacuation decisions. Findings indicate that while COVID-19 concerns played a role in some individuals' decisions, particularly those with pets or concerns about shelter conditions, the majority of participants evacuated for Hurricane Ian. The study highlights the importance of providing clear, consistent, and …

Spatiotemporal Dynamics Of Coastal Nekton Metacommunities In The Western Atlantic, Jonathan A. Peake

USF Tampa Graduate Theses and Dissertations

The processes of diversification, selection, dispersal, and stochastic drift can combine in many ways to assemble ecological communities. A key focus in ecology is to describe and quantify the relative influences of these processes for different systems and explain the mechanisms by which these processes produce patterns of community structure. To accomplish this goal, ecologists have developed several frameworks that seek to integrate processes that occur locally andregionally. The metacommunity concept treats local communities as pieces of a broader landscape that are connected through dispersal of their constituent organisms. Empirical studies have generally lagged behind the development of metacommunity theory. …

Sea Surface Temperatures, The Gulf Of Mexico Loop Current, Hurricane Ian, And Their Junction, Alexander K. Nickerson

USF Tampa Graduate Theses and Dissertations

In the first chapter, a climatology was created for the deep Gulf of Mexico, West Florida Shelf, and Tampa Bay. These climatologies were compared to each other and to global temperatures. Seasonal variability is shown to be a product of bathymetry as well as latitude. In Chapter Two, using the self-organizing map neural network, patterns of the Gulf of Mexico Loop Current were analyzed to establish phases with necessary and sufficient conditions for translation from one phase to the next. Two separate patterns of evolution were established from these analyses, and empirical arguments are used to confirm the findings from …

Characterizing The Temporal And Nearshore To Offshore Spatial Scale Of Phytoplankton Assemblages Within The Florida Keys National Marine Sanctuary, Sebastian P. Di Geronimo

USF Tampa Graduate Theses and Dissertations

This study investigates the spatial and temporal dynamics of phytoplankton communities within the Florida Keys National Marine Sanctuary (FKNMS) from 2016 to 2021. Phytoplankton biomass and community composition were analyzed across four seasons and from both Nearshore (within 2 km of shore) and Offshore (8 to 10 km from shore) locations along the Florida Keys from Miami to the Western Sambo Ecological Reserve. High-performance liquid chromatography (HPLC) quantified chlorophyll-a (tchla) as a proxy for bulk biomass, and other pigments. CHEMTAX, a chemotaxonomic identification method, was employed to estimate phytoplankton community composition. Our results revealed significant seasonal variability in bulk biomass, …

Satellite-Based Mapping Of Seagrass Habitats And Coastal Wetlands In The Us Gulf Of Mexico And Florida: A Remote Sensing Approach For Environmental Conservation And Management, Luis Lizcano-Sandoval

USF Tampa Graduate Theses and Dissertations

Coastal wetlands and seagrass meadows provide multiple services to nature and human society, but their spatial and temporal changes are often not well characterized. They are habitats that are threatened by natural and human causes such as changes in water quality, urban development, pollution, and climate change, among others. Coastal ecosystems rely on water quality and sea level variability for survival, and changes in those variables and their potential effects are of concern to many coastal communities. Satellite remote sensing is a powerful tool that has been used for mapping ecosystem distribution on land and in the ocean. Satellite sensors …

Zooplankton Abundance, Composition, And Diversity And Associated Environmental Factors Across The Gulf Of Mexico And Along The Northwestern Coast Of Cuba, Shaniqua J. Gladney

USF Tampa Graduate Theses and Dissertations

My research focused on characterizing the zooplankton community of two regions in the Gulf of Mexico (GOM) along two transects, one across the middle of the GOM from Tuxpan, Mexico, to St. Petersburg, FL, and one along the northwestern coast of Cuba. Zooplankton bongo samples and associated environmental and physical processes were examined. These data were collected during two Center for Integrated Modeling and Analysis of Gulf Ecosystems (C-IMAGE) expeditions aboard the R/V Weatherbird II, during September 2015 (GOM) and May 2017 (Cuba). A Zooscan imaging system was used to identify and enumerate zooplankton taxa. Then zooplankton abundance, composition, and …

Resolving Antarctic Margin Paleoceanography For Two Different Timescales And Archives, Theresa M. King

USF Tampa Graduate Theses and Dissertations

Recent decades have seen increased rates of ice mass loss from Antarctic ice sheets, through thinning of many ice shelves around the periphery of the continent. The most vulnerable are the glacial systems that are marine-terminating and grounded below sea level, a characteristic that exposes these systems to sea level rise and warming oceans. Enhanced basal melting under the influence of warm ocean water masses can lead to thinning and retreat of glaciers, and ultimately to the acceleration of grounded ice loss. To contextualize current ice mass loss and contribute to accurate model projections for future retreat scenarios, it is …

Antarctic Atmosphere-Ocean-Ice Interactions During Past Warm Climates: An Ice-Proximal Perspective, Imogen Mireille Browne

USF Tampa Graduate Theses and Dissertations

Antarctica’s ice sheets contain 58 m of sea level equivalent ice and thus exert a fundamental control on global sea level on decadal to million-year timescales. Interactions between Antarctica’s ice sheets, regional atmospheric circulation, and the Southern Ocean influence ice sheet mass balance, sea ice formation, and deep water production, which regulate Earth’s climate. At present, Antarctica’s fringing ice shelves and outlet glaciers, particularly in West Antarctica, are losing mass as warm ocean waters move landward across the continental shelves, melting the underside of ice shelves and eroding glacial grounding lines. In East Antarctica, net ice mass gain is occurring …

Quantification And Diversity Of A Ubiquitous Ssdna Phage Group (Gokushovirinae) In The Red Sea Through The Polony Technique, Natalie A. Sawaya

USF Tampa Graduate Theses and Dissertations

With average concentrations of 107 virus-like particles per milliliter of seawater, viruses comprise the second largest biomass in the ocean, where they are a driving force of microbial evolution and constitute important roles in Earth’s biogeochemical cycles. Bacteriophage (phage), viruses that infect bacteria, are of particular importance in the marine ecosystem as they impact the efficiency of the microbial loop, which recycles carbon in surface waters, counteracting vertical export through the biological pump. Although double-stranded DNA phage have been researched extensively, single-stranded DNA (ssDNA) phage remain understudied, mostly due to methodological limitations.

The incorporation of rolling circle amplification (RCA) into …

Subtropical Estuarine Ecosystems Display Both Long-Term Stability And Change, Garrett L. Miller

USF Tampa Graduate Theses and Dissertations

Subtropical estuaries often support abundant and diverse faunal assemblages, but it is unclear how these productive ecosystems are responding to climate change. In the eastern Gulf of Mexico, estuarine faunal assemblages have been sampled for decades as part of a fisheries-independent long-term monitoring program. I assessed trends in submerged aquatic vegetation, water temperature, and the abundance, richness, and structure of faunal assemblages over more than two decades in four estuarine systems using this dataset. I used both univariate and multivariate analyses to quantify and describe the dynamics of these habitat and faunal variables. Further, I separated my analyses for summer …

Predicting Ph At In-Situ Temperature For Aquatic Environments, Sarah E. Bartoloni

USF Tampa Graduate Theses and Dissertations

pH is typically measured at a constant temperature and, as needed, converted to in-situ temperature using a system of thermodynamic equations. Using this equilibrium approach, adjustment of pH to in situ conditions requires two measured CO2 system parameters (pH, total alkalinity, dissolved inorganic carbon, or CO2 fugacity). Currently, when pH is the only measured CO2 system parameter, linear models are used to adjust the pH to in-situ temperature. Although many studies have attempted to optimize CO2 equilibrium constants (K1 and K2) for the CO2 system over a range of conditions, very little prior work has experimentally examined which CO2 system …

Sargassum In The Florida Keys: Assessment Using High Resolution Remote Sensing, Sarah “Sully” Sullivan

USF Tampa Graduate Theses and Dissertations

Pelagic Sargassum in the Atlantic Ocean, one type of floating macroalgae, has increased in biomass and extent since 2011, bringing environmental, health, and economic issues to coastal communities. The introduction of large quantities of Sargassum to the Florida Keys, a tourism hub renowned for coral reef and marine diversity, poses a potentially devastating threat. Currently, Sargassum mats are widely monitored using medium resolution satellite imagery such as those collected by the Moderate Resolution Imaging Spectroradiometer (MODIS, 1km) and spectral band difference algorithms such as the Alternative Floating Algae Index (AFAI), but the resulting maps lack the detail and nearshore certainty …

Exploring The Dynamics Of September Fish Spawning On The West Florida Shelf Through The Dna Barcoding Of Fish Eggs, Keith G. Keel

USF Tampa Graduate Theses and Dissertations

Identifying spawning areas for economically and ecologically important fishes is critical for fisheries conservation and ecosystem-based management. Additionally, monitoring the spawning dynamics of fishes is increasingly important as temperatures and oceanic conditions change. I used genetic barcoding to identify fish eggs collected across the West Florida Shelf (WFS) during September of 2013, 2014, and 2019. Fish eggs were collected on National Oceanic and Atmospheric Administration (NOAA) Southeast Area Monitoring and Assessment Program (SEAMAP) ichthyoplankton cruises using a Continuous Underway Fish Egg Sampler (CUFES). Analysis of 4,400 fish eggs from the three years resulted in the identification of 83 unique species …

Abundance, Distribution, And Diversity Of The Paralarval Cephalopod Community In The Northern Gulf Of Mexico, Shannon Leah Riley

USF Tampa Graduate Theses and Dissertations

The abundance, distribution, and diversity of cephalopod paralarvae from the upper water column (0-130 meters) in the northern Gulf of Mexico (GOM) was studied using samples collected during six ichthyoplankton surveys between 2009 and 2012. A total of 2240 cephalopod paralarvae belonging to 21 families were examined. Octopodidae, Enoploteuthidae, and Ommastrephidae were the most abundant taxa collected in the time series. Five taxa had significantly different abundances between some sampling periods, while no significant differences in abundance occurred between any GOM regions (northwest GOM shelf, north-central GOM shelf, West Florida Shelf, GOM slope, and GOM basin). The majority of taxa …

Iron Isotope Transformations In Saanich Inlet, Claire Onak

USF Tampa Graduate Theses and Dissertations

Iron (Fe) is required for many biogeochemical processes, with Fe bioavailability and chemistry being controlled by redox reactions that transform Fe between oxidation states and dissolved and particulate phases. In oxic seawater, Fe is present in the Fe(III) oxidation state, mainly as Fe oxyhydroxides. Under anoxic marine conditions, such as margin sediments under oxygen minimum zones or restricted basins with anoxic bottom water, Fe(III) is reduced to Fe(II), which is highly soluble and can be present at high concentrations ([Fe]). Fe isotope ratios (δ56Fe relative to IRMM-14) can be used to characterize Fe redox transformations, constrain Fe sources of Fe …

Thermal Ecology And Swimming Performance Of Native Tadpoles Dryophytes Femoralis In Central Florida, Jessalyn Aretz

USF Tampa Graduate Theses and Dissertations

Urbanization and climate warming have contributed to global amphibian declines in recent decades. Amphibians are particularly vulnerable to climate and urban-induced warming because their physiological processes are dependent on temperature across all life stages, but few studies have been done on tadpole responses to warming in comparison to adult responses. The study objective was to determine how the thermal ecology and swimming performance of a native Florida tadpole varied with rearing temperature and urban level, and whether these traits are plastic or adaptive. We collected eggs from wild populations of pine woods treefrog (Dryophytes femoralis) tadpoles at an urban and …

Dissolved Nickel Speciation At The Bermuda Atlantic Time-Series Study (Bats) Site, Caitlyn E. Parente

USF Tampa Graduate Theses and Dissertations

Here I present the first depth profiles of dissolved nickel (DNi) speciation over an annual cycle at the Bermuda Atlantic Time-series Study (BATS) site in the North Atlantic. Seawater samples were collected in March, May, August, and November 2019 and analyzed for labile DNi using competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-AdCSV). Labile DNi was measured by CLE-AdCSV as the fraction of DNi that exchanges with an added competitive ligand in an overnight equilibration. Results revealed two distinct fractions of DNi present throughout the water column: a labile fraction, and a strongly organically complexed (i.e., non-labile) fraction. More than 50% …

Trace Metal Cycling During Phytoplankton Growth In The Southern Ocean, North Pacific, And Tampa Bay, Shannon Michelle Burns

USF Tampa Graduate Theses and Dissertations

The trace metals iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd) are essential to primary production in the oceans. They act as micronutrients, used in intracellular enzymes for macronutrient acquisition, light harvesting, and mediation of reactive oxygen species. In some cases, they can also substitute for each other when a primary trace metal micronutrient is depleted. Characterizing the interplay amongst trace metals, macronutrients, and phytoplankton growth is vital for understanding the biogeochemical underpinnings of primary production, and for modelers who develop biological pump frameworks for global carbon cycling.

In Chapter two, I investigated …

Procedures For Assessment Of The Marine Carbon System And Evaluation Of Access And Ocean Acidification Literacy In The Deaf Community, Loraine Martell-Bonet

USF Tampa Graduate Theses and Dissertations

One major goal of this dissertation addresses the need for improved laboratory procedures to measure chemical changes in seawater caused by the uptake of atmospheric CO2, especially in coastal environments. Due to the proximity of anthropogenic stressors in the coastal zone, the biogeochemical complexity of the CO2 system is more dynamic than the open ocean. My principal research objectives were addressed by developing methods for (1) improving the accuracy of pH measurements over a wide range of salinities and (2) investigating the acid-base properties of natural organics in the coastal ocean.

The accuracy of pH electrode calibrations is affected when …

Labile Dissolved Nickel (Ni) Concentrations In The North Pacific, Calyn M. Crawford

USF Tampa Graduate Theses and Dissertations

Nickel (Ni) is an important micronutrient for phytoplankton and bacteria that serves as a required co-factor in several metalloenzymes. Despite these known biological uses, total dissolved Ni concentrations remain elevated in global surface waters, in contrast to the surface depletion commonly observed for macronutrients and other nutrient-type trace elements. A prevailing hypothesis for the muted depletion of dissolved Ni concentrations in surface waters is that dissolved Ni in seawater is not in a bioavailable form. The chemical lability of Ni in seawater provides insight into Ni speciation and bioavailability, but few measurements have been made in the open ocean to …

Time-Series Analysis Of Coral Reef And Reef-Fish Biodiversity In The Florida Keys National Marine Sanctuary, Cara L. Estes

USF Tampa Graduate Theses and Dissertations

The general decline in coral-reef ecosystem health throughout the Caribbean between the 1970’s and late 1990’s seems to have slowed down or stopped, with only slight decreases in coral reef cover observed in the 2000’s through 2019. The earlier decline can be attributed to many different local and regional stressors that have acted together, and include naturally occurring (hurricanes, diseases) and anthropogenic pressures (increased sedimentation, fishing). These ecosystems provide a range of services to people, including food and protection from storms, with an annual benefit of billions of dollars. This has driven a desire to better understand these ecosystems. The …

Stable Isotope Analysis On Yellowfin And Blackfin Tuna Eye Lenses Reveals Life History Patterns In The Gulf Of Mexico, Kylee M. Rullo

USF Tampa Graduate Theses and Dissertations

Spatial geography, ontogenetic movement, and trophic patterns of mobile species are key elements of effective marine resource management. A number of methods are currently available for tracking movements of pelagic migratory species, including the use of conventional and electronic tags. However, tagging campaigns can take years to provide useful data, can be expensive, and only capture a portion of a fish’s lifetime. For this project, I used stable-isotopic ratios of nitrogen (δ15N) and carbon (δ13C) in metabolically inert, chronologically-layered fish-eye lenses to explore lifetime movement and trophic patterns of yellowfin tuna (Thunnus albacares) and blackfin tuna (Thunnus atlanticus) in the …

Meta-Analysis Of United States Seabird Populations Based On Ocean Biodiversity Information System (Obis) Records (1965–2018), Savannah Hartman

USF Tampa Graduate Theses and Dissertations

Understanding the distribution of organisms is an important priority for society as we live through ecosystem transformations that threaten the well-being of all organisms. I have approached the dynamic and complex issue of studying biodiversity by using open-access seabird data collected along the Americas since the 1960s. I explained how these data have changed over time and space, how certain species populations could have shifted over time, and possible correlations between this potential geographic change and select environmental variables.

In Chapter 2 I evaluated the suitability of the open-access data archive Ocean Biodiversity Information System (OBIS) for supporting detailed inquiry …

Exploring The Impact Of Eddies On Southern Ocean Biogeochemical Structure Using Bgc-Argo Float Observations, Nicola J. Guisewhite

USF Tampa Graduate Theses and Dissertations

The Southern Ocean plays a crucial role in global ocean circulation, and global heat and nutrient transport. However, this region is both distant and dangerous and is therefore largely under-sampled and understudied. Methods to fill in biogeochemical data-gaps include using limited in-situ data in models to output biogeochemical property estimates, but a number of recent studies have raised concerns about how most Southern Ocean models do not resolve eddies. Eddies are known to impact biogeochemistry around the globe but little is known about their impact in the Southern Ocean. This study examines temperature, salinity, oxygen, nitrate, and dissolved inorganic carbon …