Digital Commons Network^™

Field And Remote Sensing Analysis Of The 2015 Pyroclastic Density Currents At Colima (Mexico) And Calbuco (Chile) Volcanoes: Implications For Hazard Assessment And Crisis Management, Elodie Macorps

USF Tampa Graduate Theses and Dissertations

Although one of the most spectacular phenomena of active volcanoes, Pyroclastic density currents, or PDCs, are considered the most dangerous volcanic hazards. PDCs are avalanches of hot volcanic gases, ash, and larger volcanic fragments that travel at incredible speed down the flank of a volcano. High dynamic pressures, high temperatures, and high velocities are the primary dangers associated with PDCs and lead to near-complete destruction and death.

I use a multi-disciplinary approach to study the deposits left behind by PDCs, in order to understand their dynamics, their interactions with the receiving landscape, and their final distribution, starting on the ground …

Archaeology And Seasonality Of Stock Island (8mo2), A Glades-Tradition Village On Key West, Ryan M. Harke

USF Tampa Graduate Theses and Dissertations

Later Glades-period cultures (ca. 500–1760 CE) of south Florida and the Florida Keys are understudied and thus poorly understood, especially those that pre-date the arrival of Spaniards to the New World. Recent archaeological models of their sociopolitical organization suggest that by the Glades I-II transition (750/800 CE), south Florida peoples were organized into what appear to be regional population centers (e.g., Pineland and Mound Key, Granada, Turner River) and smaller hinterland towns in the Everglades (e.g., Cane Patch, Bear Lake) and the Florida Keys (e.g., Stock Island, Clupper Site). Smaller towns are hypothesized to be sedentary, heterarchically-organized, simple chiefdoms from …

Past Ice-Ocean Interactions On The Sabrina Coast Shelf, East Antarctica: Deglacial To Recent Paleoenvironmental Insights From Marine Sediments, Kara J. Vadman

USF Tampa Graduate Theses and Dissertations

The East Antarctic Ice Sheet (EAIS) contains ~53 meters of sea level equivalent (SLE) ice, and observations suggest it is sensitive to ongoing and past climate change. The EAIS has traditionally been considered insensitive to climate perturbations because it is largely grounded above sea level. However, aerogeophysical surveys, oceanographic observations, and models indicate that large areas of the EAIS are grounded below sea level and contain 19.2 m SLE. Marine-based parts of the EAIS are thought to be located on inland-sloping beds that drain through marine terminating outlet glaciers, indicating large areas of the EAIS may be more sensitive to …

Investigating The Hydrology Of The Western Greenland Ice Sheet: Spatiotemporal Variability And Implications On Ice-Dynamics, Jessica Z. Mejia

USF Tampa Graduate Theses and Dissertations

Since the 1990's the Greenland Ice Sheet (GrIS) has been losing mass at an accelerating rate in response to climatic warming and is currently the largest terrestrial contributor to sea-level rise. While ice sheet models agree the GrIS will continue losing mass throughout the century, there are significant uncertainties associated with future sea-level rise contributions. Predicting the GrIS's response to future climate warming scenarios is limited by gaps in our understanding of the links between ice sheet hydrology and dynamics. Meltwater produced on the ice surface flows within supraglacial streams that deliver it to crevasses or moulins—vertical conduits extending from …

Investigation Of Hurricane Irma Deposits, Big Pine Key, Florida, Youzhu Wang

USF Tampa Graduate Theses and Dissertations

Few paleotempestological studies have focused on coastal sinkholes, a common feature in Florida, which can receive and preserve storm overwash sediments. The major goal of this research is to improve our understanding of the characteristic signatures of storm sediments in sinkholes thereby determining reliability of these environments as proxies for hurricanes. Hurricane Irma as a Category 5 storm provides an excellent case study for characterizing storm deposits in sinkholes on Big Pine Key. I cored at four sinkholes along a 350 m transect normal to the shoreline. Core sediments were characterized using physical description, short-lived radioisotope dating, sediment grain size …

Impacts Of Experiential Learning On The Affective Domain: Gaining Insight Into How To Broaden Participation In The Geosciences, Meghan Lindsey Cook

USF Tampa Graduate Theses and Dissertations

Experiential learning exercises, such as field trips, are a common pedagogical practice in geoscience curriculums. Their purpose is to facilitate the transfer of knowledge gained in a classroom or lab setting into a field setting, but can be considered a barrier for entry into the geosciences for those with disabilities, caregiver/employment responsibilities, or financial constraints. Educators have begun turned to other modalities, such as virtual field experiences (VFEs), to create a more inclusive environment in the geosciences. However, the validity of VFEs as a replacement for, or augmentation to traditional field trips has yet to be established. The cognitive domain …

Seismic Attenuation, Time Delays And Raypath Bending Of Teleseisms Beneath Uturuncu Volcano, Bolivia, Alexandra K. Farrell

USF Tampa Graduate Theses and Dissertations

A set of 14 teleseismic earthquakes was studied to determine how wave propagation was affected by a presumed magma body beneath Uturuncu volcano, Bolivia. Teleseisms are suitable for study because they are relatively long period, contain purely P waves, and have near-vertical incidence angles. The number of events is small but the events have good signal-to-noise ratios and very similar waveforms for each event so that reliable measurements could be made of arrival times and amplitudes. Attenuation of amplitudes occurs in a NW-SE trend beneath the volcano, 14 by 34 km (long axis NW-SE). Calculated values of the quality factor …

Investigating The Recent History Of A Changing Planet With Innovative Isotopic Techniques And New Geologic Archives, Ryan A. Venturelli

USF Tampa Graduate Theses and Dissertations

Globally averaged Earth surface temperatures indicate a 0.8°C warming since 1880. Though this warming is a result of anthropogenic influence that has exceeded natural forcings, a thorough understanding of Earth's climate system requires a knowledge of changes in global temperatures beyond the instrumental record. To achieve this, we must supplement the temporally limited observational record with proxy records of environmental conditions in the geologic past. Though the foundational questions underlying interrogations of the geologic past are seemingly simple (What happened? When?), the accuracy of their answers depend upon accessibility and availability of geologic materials as well as the capabilities of …

Plio-Pleistocene Antarctic Ice-Ocean Interactions In The Ross Sea, Catherine Prunella

USF Tampa Graduate Theses and Dissertations

Warm, intermediate-depth Southern Ocean waters are implicated in recent Antarctic ice mass loss. Direct observations of Antarctic Ice Sheet (AIS) retreat are temporally limited, necessitating paleoceanographic records of ocean-ice interactions during past warm climate intervals. Deepsea and ice-proximal sediments record orbitally-paced glacial-interglacial fluctuations in AIS volume during the Plio-Pleistocene (last 5 million years; Ma), but the total contribution of the AIS and the role of ocean heat in these fluctuations remain unresolved. To address the response of Antarctica’s ice sheets to changing ocean temperatures during the Plio-Pleistocene, International Ocean Discovery Program (IODP) Expedition 374 recovered sediments from the Ross Sea …

Porosity And Permeability Extremes In An Eogenetic Carbonate Platform: Mechanisms For Formation And Implications For Fluid Flow, Charles I. Breithaupt

USF Tampa Graduate Theses and Dissertations

Carbonate rocks contain about a third of the worlds drinking water and host 60-70% of proven hydrocarbon reserves. Effective development and management of these resources relies heavily on geologic concepts used to predict the distribution, and magnitude of porosity and permeability in the aquifer or reservoir. Most geologic concepts used for flow prediction have been developed in telegenic limestones, where fracture networks, bedding plains, and conduits hosted in effectively impermeable bedrock control the movement of fluids, and evolution of porosity. However, a growing body of work has recognized fluid flow within eogenetic limestones is fundamentally different, and that new concepts …

Save Water Drink Wine: Challenges Of Implementing The Ethnography Of The Temecula Valley Wine Industry Into Food-Energy-Water Nexus Decision-Making, Zaida E. Darley

USF Tampa Graduate Theses and Dissertations

This study demonstrates the interrelationships of people, food, energy, and water associated with Temecula Valley’s wine industry and reveals contradictions and biases in how people view these resources, which ultimately shape management and policies. The FEW (Food, Energy, and Water) Nexus is an approach increasingly used by policy- and decision-makers to understand the interrelationship of several resources. However, a FEW Nexus approach often lacks in social aspects that influence environmentally and economically sustainable outcomes, especially in the wine and wine tourism industry. When quantitative and qualitative data are available, the other challenge is which assessment to use. Two assessments often …

Coral Reef Restoration In The Tropical West Atlantic Amid The Covid-19 Pandemic, Linden Cheek

USF Tampa Graduate Theses and Dissertations

Climate change is increasing threats to coasts, both from storm surge and sea level rise. Healthy coral reefs provide reduction in storm surges, wave energy, coastal flooding and everyday erosion, and are found across a variety of spatial scales. Given the state of coral reefs worldwide, active Coral Reef Restoration (CRR) in emerging as a necessary component of coastal protection. CRR can be classified as a nature-based solutions (NbS) for coastal protection that also provides a multitude of ecosystem-based services to both humans and other life. Nearly all literature on coral restoration efforts assume a steady-state of human-ecological interactions, but …

Assessment And Integration Of Socioeconomic And Demographic Factors In The Implementation Of Integrated Water Resources Management In The Lake Chad Basin, Nodjidoumde Mbaigoto

USF Tampa Graduate Theses and Dissertations

Most developing countries have responded to the 2002 World Summit on Sustainable Development (WSSD) call to implement Integrated Water Resources Management (IWRM) in their national water policy to reach water sustainability and socioeconomic welfare. Despite the Lake Chad Basin Commission's adoption of the IWRM principles, the basin experiences a massive humanitarian crisis driven by the lake's shrinkage, the water shortage for food production, the rapid population growth, and the terrorist attacks perpetrated by Boko Haram. This study sought to assess the socioeconomic and demographic status of people living upstream of Lake Chad in order to understand the challenges associated with …

Using Tidal Analysis To Examine Lake-Aquifer Connectivity On A Modern Carbonate Platform, Ronald A. Knoll

USF Tampa Graduate Theses and Dissertations

Lake-aquifer connectivity on carbonate platforms is governed by basin morphology which is influenced by diagenetic and depositional processes. Both these processes cause aquifer permeability to vary significantly with scale of measurement (i.e., pore-scale, well-scale, and regional-scale). Because coastal aquifers are well-known to have tidally controlled water level fluctuations, inland lakes may be used to expand the areal measurement of permeability and establish a link between well-scale and regional scale connectivity in the aquifer. To evaluate the impact of lake basin morphology on aquifer connectivity, water level fluctuations were collected at high temporal resolution in the ocean and twenty-four surface water …

Using Geospatial Data To Predict The Locations Of Groundwater Discharge To Salmon-Bearing Streams, Alaska, Mary Gerlach

USF Tampa Graduate Theses and Dissertations

Identification and protection of groundwater resources are considerations of increasing interest as climate shifts but can be challenging to accomplish in remote areas. To that end, a series of GIS techniques and weight of evidence approach were applied to determine the feasibility of remotely identifying likely areas of ground discharge. Through the confluence of topographic analyses and a novel geologic dataset, these techniques were found to consistently identify areas characterized by either shallow subsurface or aquifer-fed groundwater discharge or evidence of ephemeral surficial water features. Two distinct GIS techniques to build spatial proxies of the effects of topography and geology …

A Process-Based Approach To Evaluating The Role Of Organic Ligands In Trace Metal Cycling In The Marine Environment, Travis Mellett

USF Tampa Graduate Theses and Dissertations

In addition to control by major nutrient elements (nitrogen, phosphorous, and silicon) growth and community composition of marine phytoplankton is also regulated by trace element nutrients (iron, copper, manganese, zinc, cobalt, nickel, and cadmium). Of these, iron is the most influential in the modern ocean, regulating phytoplankton growth and carbon export in high-nutrient low-chlorophyll regimes and exerting an important control on the marine nitrogen cycle through its role in di-nitrogen fixation. The distributions of these metals has the capacity to control primary production and phytoplankton community composition through differences in cellular quotas or metal sensitivities amongst species. The relationship between …

The Effects Of Surface-Water Flow On The Quality Of Groundwater And Surface-Water Systems, Quanghee Yi

USF Tampa Graduate Theses and Dissertations

My research has focused on the effects of surface-water flow on the quality of groundwater and surfacewater systems. For the first part of my research (Chapter 2 ), I s tudied the effects of s urface flow system changes in the water-conservation areas and canals in southeast Florida on the quality of groundwater in the surficial aquifer system.

For the second part of my research, by developing analytical models using the superposition method, I investigated the effects of bidirectional surface-water flow on the conservative contaminant concentrations (Chapter 4) and mean residence time (Chapter 5) in streams and rivers as well …

Biogeochemical Cycling Of Nutrients And Carbon In Subtropical Wetlands, Lauren N. Griffiths

USF Tampa Graduate Theses and Dissertations

As human development intensifies, ecosystems around the word are being exponentially destroyed and degraded. Wetlands have the capacity to mitigate some of the possible problems by retaining nutrients and carbon, keeping them from harming downstream ecosystems or being released into the atmosphere. This project focuses on the processes that make wetlands successful by studying two unique ecosystems: 1) a created urban stormwater treatment wetland and 2) mangrove wetlands in Florida and Puerto Rico that were affected by hurricanes in 2017.

The first phase of this study investigates the role of sedimentation and vegetative and algal uptake of nutrients to retain …

Using Geophysical And Geodetic Data To Improve Natural And Human-Induced Hazard Assessments, Fanghui Deng

USF Tampa Graduate Theses and Dissertations

I use geophysical and geodetic data to study dynamics of the Earth System, including volcanoes and induced seismicity, aiming to improve related hazard assessment at different time and space scales. My dissertation consists of the following three projects: 1) Geophysical model for the origin of volcano vent clusters (Deng et al., 2017). We developed a conceptual model to simulate long-term magma transport to explain the origin of volcanic vent clusters in Quaternary Colorado Plateau volcanic fields. We used density contrast inverted from gravity data to constrain the magma transport model. The development of vent clusters appears to be influenced by …

Development Of A Benthic Foraminifera Based Marine Biotic Index (Foram-Ambi) For The Gulf Of Mexico: A Decision Support Tool, Bryan O'Malley

USF Tampa Graduate Theses and Dissertations

The Gulf of Mexico (GoM) is an economically important region (e.g. oil and gas, fisheries) and with the expansion of oil drilling, harmful algal bloom events, oil blowouts, dead zones, anthropogenic eutrophication and contaminant loading, it is important that the ecological quality statuses (EcoQS) of different localities in the Gulf are closely monitored. The EcoQS, as implemented by the European Water Framework Directive, is an effective tool for monitoring ecological health and developing reference conditions. One such index used to define EcoQS is the AZTI Marine Biotic Index (AMBI), which pairs species abundance with environmental stressors. Benthic foraminifera are ideal …

Investigating The Isotope Signatures Of Dissolved Iron In The Southern Atlantic Ocean, Brent A. Summers

USF Tampa Graduate Theses and Dissertations

Iron (Fe), used as a cofactor in nitrogen fixation and photosynthesis by oceanic microorganisms, has extremely low dissolved concentrations in the surface ocean, leading to widespread limitation of phytoplankton growth. Dissolved Fe isotope ratios (δ56Fe) have been shown to be useful in helping to quantify the sources and cycling of Fe in the oceans if Fe source signatures and fractionation processes are well understood. Here, this thesis presents data from GEOTRACES section GA10W, and investigate the isotopic signature of sediment-derived dissolved Fe from the South Atlantic margins. My results show that there are both shallow (δ56Fe of -0.2‰) and deep …

Spatiotemporal Changes Of Microbial Community Assemblages And Functions In The Subsurface, Madison C. Davis

USF Tampa Graduate Theses and Dissertations

The subsurface hosts diverse microbial community assemblages and functions. These communities play an important role in biogeochemical cycling and groundwater purification. Many physicochemical factors affect microbial communities and can cause short-term or long-term perturbations. Subsurface microbes are susceptible to anthropogenic changes in the environment, which can be caused by nutrient inputs or municipal groundwater extraction. Despite the importance of the subsurface microbiome, these microbial communities are poorly characterized. This dissertation describes the characterization of spatiotemporal drivers of subsurface microbial communities through a variety of techniques that include eDNA analyses, bioinformatics, hydrochemical analyses, stable isotope geochemistry, and multivariate statistics. Three coastal …

The Ecology And Conservation Of An Urban Karst Subterranean Estuary, Robert J. Scharping

USF Tampa Graduate Theses and Dissertations

Sulphur Springs is an artesian spring and part of the limestone karst topography of metropolitan Tampa, Florida, USA. Underlying this spring is an extensive cave system that hosts saltwater vents and conspicuous microbial biofilm communities. For decades, water from Sulphur Springs has been extracted and used to supplement public water supply and dry season flows in the Hillsborough River Estuary. This dissertation describes research conducted at Sulphur Springs to determine the impacts of urban land use on the underlying cave and downstream estuary ecosystems, and presents the use of this system as a model to fill certain ecological knowledge gaps. …

Mechanisms Of Carbon Movement And Stabilization In Mangrove Wetlands, Carey Schafer

USF Tampa Graduate Theses and Dissertations

Mangrove forests have higher rates of carbon storage per unit area than any other coastal or terrestrial habitat, largely due to their significant soil stocks. More effort has been placed on quantifying mangrove soil carbon stock, the amount of carbon stored in the upper meter of mangrove soils, than identifying the processes governing in situ soil organic carbon (SOC) cycling and stabilization. An understanding of the mechanisms related to carbon transport and stability is necessary to constrain current wetland carbon stocks and to determine how sea level rise will impact future carbon stores. This study uses a variety of radiometric …

Assessment Of Land Cover Change In St. Martin’S Marsh Aquatic Preserve, Florida, Usa, Katie Wagner

USF Tampa Graduate Theses and Dissertations

St. Martin’s Marsh Aquatic Preserve (SMMAP) is a 28,461 acre (115.18 km2) preserve located on the coast of Citrus County, Florida, USA. There has been no published research that focused on coastal change on this unique coast. This thesis research focuses on coastal land cover change that has occurred within the preserve from 1988 to 2018. Multitemporal Landsat images were classified using a support vector machine (SVM) classification, while changes in vegetation were evaluated using the normalized difference vegetation index (NDVI). Field research was conducted to examine nineteen sites for classification training and test data and notes on habitat composition. …

Shallow Water Seafloor Geodesy: Gps On An Anchored Spar Buoy, Surui Xie

USF Tampa Graduate Theses and Dissertations

Measuring seafloor motion in shallow coastal water is challenging due to strong and highly variable oceanographic effects. Such measurements are potentially useful for monitoring near-shore coastal subsidence, subsidence due to petroleum withdrawal, strain accumulation/release processes in marine shelves and submerged volcanoes, and certain fresh water applications, such as volcano deformation in caldera-hosted lakes. I participated in a project to develop a seafloor geodetic system for this environment based on an anchored spar buoy topped by high precision GPS. Orientation of the buoy is measured using a digital compass that provides heading, pitch, and roll information. The combined orientation and GPS …

Reconstructing Geographic And Trophic Histories Of Fish Using Bulk And Compound-Specific Stable Isotopes From Eye Lenses, Amy A. Wallace

USF Tampa Graduate Theses and Dissertations

The present research examined the viability and utility of eye lenses as a source of lifetime stable-isotope records in fish. It is presented in three sections. The first section compared bulk isotopic variation (bulk analysis) within fish eye-lenses at two temporal resolutions and compared patterns obtained from left and right eyes. The first temporal resolution was lower in an attempt to expose broad-scale isotopic changes during life while reducing effort and cost. This approach did reveal lifetime patterns, but tended to miss certain life events, particularly during early life. The second resolution was higher and provided detail that was missed …

The Peculiar Nature Of Florida’S Sandhill Wetlands, Ponds & Lakes— Their Ecohydrology, Relationship With The Regional Aquifer & Importance Within The Landscape., Renae Starr Nowicki

USF Tampa Graduate Theses and Dissertations

This dissertation explores the ecohydrology of Florida’s peculiar and poorly studied sandhill wetland and water features, particularly those located in west-central Florida. The primary research goals include: compilation and summarization of the available ecohydrologic information for features across Florida; comparison of water level and water geochemistry data between sandhill wetlands and waters and the regional aquifer to provide evidence of regional hydrologic control; and use of geophysical applications to examine the hydraulic connections between sandhill wetlands and waters and the regional aquifer.

From this research, a natural history of sandhill wetland and water ecohydrology is presented, highlighting: the differences between …

Effects Of Reservoir Conditions And Trace Co-Contaminant Gases On Geological Carbon Sequestration, Ram Kumar

USF Tampa Graduate Theses and Dissertations

Geological carbon sequestration in a saline formation is a promising technology for large-scale carbon dioxide (CO2) mitigation. Several factors such as temperature, pressure, salinity, hydraulic conductivity, and mineralogy of a formation affect the CO2 sequestration in saline formations. These factors can vary widely depending upon the type of formation or the degree of heterogeneity within a formation. In addition to these properties of the repositories, the CO2-rich flue gas streams captured from point sources often contains small amounts of impurities such as sulfur oxides (SOx) and nitrogen oxides (NOx), which may have serious implications on the chemistry of the repositories …

Boron Variation And The Subducted Sediment Component In The Volcanics From The Bifurcated Portion Of The Lesser Antilles Island Arc (Laia), Ami Margret Ngo Ward

USF Tampa Graduate Theses and Dissertations

North of Martinique island the Lesser Antilles volcanic arc bifurcates, creating a double arc. Here volcanic activity has migrated up to 50 km westward with time, resulting in two volcanic lines that are distinct in age. The eastern line, commonly referred to as the old arc, was active from Early Eocene to Mid-Miocene (Nagle, 1971; Nagle et al., 1976; Westercamp and Tazieff, 1980; Andreieff et al., 1988). The western line, commonly referred to as the recent arc, has been active since the late Pliocene, ~6 Ma ago (Nagle, 1971; Nagle et al., 1976; Westercamp and Tazieff, 1980; Andreieff et al., …