Physical Sciences and Mathematics Commons^™

An Assessment Of Climate Mobility Pressures In Response To Dynamic Sea-Level Rise, Nadia A. Seeteram

FIU Electronic Theses and Dissertations

Sea-level rise (SLR) and related flooding impacts will contribute to migration across coastal communities around the world. Differential exposure to impacts, societal vulnerability, and adaptive capacity will invariably lead to varying climate-related mobility outcomes for residents of these communities. Residents of Miami-Dade County (MDC), FL, USA are at substantial risk to the direct and indirect impacts of SLR and related flooding. As the 2nd most economically unequal metropolitan area in the U.S. according to the Gini coefficient (0.508), without strategic intervention, marginalized and vulnerable communities across MDC will disproportionately face unequal mobility pressures. This dissertation seeks to understand the potential …

Provenance, Composition And Transport Processes Of Pleistocene-Recent Turbidite Sediments Of The Se Nazca Plate, Odp Site 1232, Kimberly D. Beck

FIU Electronic Theses and Dissertations

A 300 meter sequence of Pleistocene turbidite deposits was recovered on the Nazca Plate at the subducting edge of the Peru-Chile Trench at ODP Site 1232. Analysis of the coarsest particles in the turbidite sequences implies sediment was supplied in some proportion by terrestrial erosion and originated in the coastal, central, and Andean volcanic/magmatic belt which parallels the Southern Chilean coast, and the predominant material type is volcanic. Petrographic and geochemical analyses show that samples from 3 - 140 mbsf contain >43% fresh, angular glass. New calcareous nannofossil biostratigraphy brackets the sediment ages of the upper 288 m of cored …

Hydrologic Properties Of Mangrove And Sawgrass Peat In Shark River Slough, Everglades, Florida, Nicole Cordoba

FIU Electronic Theses and Dissertations

Peat sediments are the foundation of most wetlands, acting as a medium for water to flow through, governed by hydraulic conductivity, and as a potential source of nutrients. Shark River Slough is a known, main fresh waterway for Everglades National Park, distributing essential nutrients and freshwater into the wetland. Hydraulic conductivity was calculated through experimental (both in situ water and higher salinity water) falling head tests performed on mangrove and sawgrass peat cores. Nutrient concentrations were analyzed for the pore water released during hydrologic testing. Hydraulic conductivity values were higher in the sawgrass peat than the mangrove peat. No significant …

Evaluating Changes In Visible To Short-Wave Infrared Spectral Reflectance Of Arctic Mosses In Response To Experimental Drying To Find The Best Predictors Of Moisture Content, Steven L. Unger

FIU Electronic Theses and Dissertations

Mosses are a dominant understory component in the Arctic and because of sparse canopy cover, contribute to spectral signals used in remote sensing estimates of various ecologically important characteristics such as productivity, phenology, and vegetation mapping. However, little is known about their contributions to community level spectra or how moisture content influences those spectral signals. Unlike vascular plants, mosses cannot actively regulate moisture content and are highly susceptible to desiccation. Previous research has shown that moss reflectance is sensitive to tissue moisture content. Here, a lab-controlled drying experiment was conducted to identify the best spectral predictors of moisture content of …

Drivers Of Extracellular Polysaccharide Production By A Mat-Forming Diatom, Kaitlin A. Stansbury

FIU Electronic Theses and Dissertations

Microbial biofilms are held together by extracellular polymeric substances (EPS), which can be secreted by many organisms. EPS production can facilitate intercellular communication and inter-guild microbial mutualisms, intraspecific gamete exchange, nutrient sequestration, and desiccation resistance. Benthic microbial mats (periphyton) of the Florida Everglades and other karstic wetlands contain abundant EPS generated by mat-producing filamentous blue-green algae and many other species of mat-dwelling algae, cyanobacteria, and bacteria, including the most abundant Everglades diatom, Mastagloia calcarea. The benthic diatom genus Mastogloia is characterized by several morphological and physiological features that foster production of a ‘halo’ of EPS around the frustule, but the …

Integrating Compound Flood Conditions Through 2d Hydraulic Modeling For Simulating Flood Risk Processes In Coastal Cities, Francisco Pena Guerra Mr.

FIU Electronic Theses and Dissertations

Low elevation coastal karst environments are highly vulnerable to flooding conditions due to climate change. Trends in rising global temperatures have increased the frequency and intensity of extreme precipitation, hydrometeorological phenomena and sea level rise, exacerbating the impact of pluvial, fluvial, coastal and groundwater flood hazards. Compound flooding events amplify flood hazards and pose a higher threat to residents and infrastructure in unison compared to independent phenomena. Recent advancements in coupling hydrologic and hydraulic modeling frameworks have improved our ability to account for the combined effects of extreme pluvial, fluvial, and coastal flood hazards. This innovation in the hydroinformatics field …

Quantifying How Coastal Flooding And Stormwater Runoff Drive Spatiotemporal Variability In Carbon And Nutrient Processing In Urban Aquatic Ecosystems, Matthew A. Smith

FIU Electronic Theses and Dissertations

Coastal river networks alter the transport and transformation of dissolved organic carbon (DOC) and dissolved organic matter (DOM), which can vary in concentration and composition across spatiotemporal scales. Given climate-induced shifts in rainfall and tidal variation in low-lying coastal regions, there is an increasing need to quantify effects of flooding on biogeochemical cycling. Specifically, urban flooding is becoming increasingly common due to biophysical alterations to hydrology from urbanization and climate change. Urban ecosystems have been characterized as having a distinct biogeochemistry compared to other systems, largely due to increased frequency and magnitude of riverine and coastal flooding. Consequently, the role …

Comparison Of Modern And Mid-Holocene Benthic Foraminifera To Assess Recent Environmental Change In Almirante Bay, Caribbean Panama, Maria N. Gudnitz

FIU Electronic Theses and Dissertations

This study used the diversity and distribution of benthic foraminiferal assemblages of Almirante Bay, Caribbean Panama, as environmental proxies to compare modern coral, seagrass and mangrove habitats to mid-Holocene coral reef facies on the island of Isla Colón, to investigate both natural and human-influenced changes.

The modern study associated species and assemblage characteristics with environmental conditions related to degraded water quality. Assemblages were fairly similar among neighboring habitats but differed in species proportions, while several stress-tolerant taxa might indicate eutrophic conditions. Diversity appeared to be regionally controlled by freshwater input irrespective of habitat type, was generally lower near the mainland …

Microphysical-Dynamical Interaction In Tropical Cyclone Intensification, Zongyao Yang

FIU Electronic Theses and Dissertations

Producing timely and accurate tropical cyclone (TC) intensity forecasts remains one of the most difficult challenges facing meteorologists today. The state-of-the-art three-dimensional (3D) full physics operational models, in particular, have problems in simulating rapid intensification (RI), a situation where a TC intensifies dramatically in a short period of time. For example, Hurricanes Patricia (2015) and Maria (2017) increased their maximum sustained winds by 90 knots and 70 knots within 24 hours, respectively. The major objectives of this dissertation are to (a) explore the underlying reasons why the Hurricane Weather Research and Forecasting (HWRF) system, one of the operational models used …

Connections In The Underworld: A Morphological And Molecular Study Of Diversity And Connectivity Among Anchialine Shrimp., Robert Eugene Ditter

FIU Electronic Theses and Dissertations

This research investigates the distribution and population structure of crustaceans, endemic to anchialine systems in the tropical western Atlantic focusing on cave-dwelling shrimp from the family Barbouriidae. Taxonomic and molecular tools (genetic and genomic) are utilized to examine population dynamics and the presence of phenotypic hypervariation (PhyV) of the critically endangered species Barbouria cubensis (von Martens, 1872). The presence of PhyV and its geographic distribution is investigated among anchialine populations of B. cubensis from 34 sites on Abaco, Eleuthera, and San Salvador, Bahamas. Examination of 54 informative morphological characters revealed PhyV present in nearly 90% (n=463) of specimens with no …

Hydrogeophysical Characterization And Imaging In The Mangrove Lakes Region Of Everglades National Park And Big Pine Key, Florida, Usa, Michael Eyob Kiflai

FIU Electronic Theses and Dissertations

Coastal groundwater aquifers are susceptible to saltwater intrusion from natural and anthropogenic sources. Everglades National Park (ENP) has been adversely impacted by past human activities that altered freshwater flow through the system. In Big Pine Key (BPK), the flat and low-lying topography less than 2m makes the freshwater lens vulnerable to tidal and storm surge events. This study investigated different inversion scenarios and used Electrical Resistivity Tomography (ERT) and Electromagnetic (EM) survey to characterize the spatial and temporal change of the groundwater chemistry and image the aquifers. In Big Pine Key, Hurricane Irma made landfall as a category 4 storm …

Modeling Drought, Drought Teleconnection, And Its Effect On Groundwater Level Dynamics In The Biscayne Aquifer, Anteneh Z. Abiy

FIU Electronic Theses and Dissertations

Developing a self-sufficient water supply system in Southeast Florida is one input to the success of the ongoing restoration effort in the Everglades. Maintaining a high groundwater level in the urban side of the Biscayne Aquifer (BA) is important to sustain the urban water supply. However, the long-term groundwater table condition in the Biscayne Aquifer (BA) is threatened by a combination of drought, groundwater pumping, and sea-level rise. Further, the long-term drought pattern, drought drivers, and the aquifer’s response to drought and other stress conditions are not well known. As a result, options that would help to maintain a high …

Volcanic History Of The Izu Bonin Mariana Arc Prior To The First Arc Rift From Volcaniclastic Sediments Of Dsdp Site 296 And Iodp Site 1438, Eshita Samajpati

FIU Electronic Theses and Dissertations

The Izu-Bonin Mariana (IBM) island arc in the western Pacific basin is a volcanic chain formed by subduction of the Pacific lithospheric plate beneath the Philippine Sea plate. Worldwide, subduction causes high-magnitude earthquakes and explosive volcanic activity in addition to forming the Earth’s continental crust and major ore deposits, thus its understanding is important to human concerns. In the IBM, volcanic activity spans 50 million years to the present and the arc has undergone extension and periodic rifting, preserving remnants of its early history. The Kyushu Palau ridge (KPR), an inactive Oligocene remnant of the rifted IBM system, is a …

Lithological And Geochemical Responses To Abrupt Global And Regional Paleoenvironmental Changes During The Aptian In A Hemipelagic Setting Of The Eastern Iberian Peninsula: A Multi-Proxy Approach, Jander Socorro

FIU Electronic Theses and Dissertations

Intense episodes of environmental perturbations and regionally to globally distributed, oxygen-deprived marine facies characterize the Cretaceous sedimentary record. The Organyà Basin in the Spanish Pyrenees chronicles this period in expanded stratigraphic sequences that enabled high-resolution sampling and detailed analysis of disturbances poorly recorded in more lithologically condensed sections. Here, I present an integrated multi-proxy study aimed at understanding the Basin’s response to changing paleoenvironmental conditions during the early Aptian stage of the Cretaceous.

Results from the El Pui section indicate that large-scale (> 1‰), negative carbon isotope excursions (CIEs) that show no corresponding shifts in local sources of organic matter …

Evaluation Of Pre-Eruptive Conditions For Cordon Caulle Rhyo-Dacitic Historic Eruptions, Mauro Andres Mingo

FIU Electronic Theses and Dissertations

For better understanding of Plinian-hybrid eruptive events, I analyzed the variables that affect the pre-eruptive conditions of the latest three eruptive events of the Puyehue Cordon Caulle Volcanic Complex (PCCVC). The analysis was done by performing a petrological study of lava samples followed by Electron Probe Microanalysis (EPMA) on selected mineral phases. Mineral data were then used in established mathematical models to calculate pre-eruptive magma temperature and water content. The acquired data are compared to bulk measured water content, and the difference is utilized to estimate viscosities and evaluate the degassing regime. Results indicate that the historic eruptive events have …

Wavenumber-1 Vortex Rossby Wave Propagation In The Inner Waveguide Of A Modeled, Barotropic Nondivergent Tropical Cyclone, Israel Gonzalez

FIU Electronic Theses and Dissertations

Vortex Rossby waves (VRWs) have been shown to influence tropical cyclone (TC) structure and intensity change. However, the role of VRWs in TC motion and analyses of the inner waveguide within which the waves propagate have received limited attention. Therefore this dissertation primarily focuses on modeling wavenumber-1 VRWs in a barotropic, nondivergent context to investigate TC-like vortex motion, acquire deeper understanding of propagation within the widest possible inner waveguide, and compare with higher-wavenumber studies.

A mass source-sink pair rotating with a specified frequency is imposed in a mean vortex’s eyewall to excite VRWs. Forced waves manifest as vorticity filaments that …

Stable Isotope Analysis Of Japan Sea And East China Sea Sediments: Late Pleistocene Paleoceanographic Reconstructions, Heather Dawn Black

FIU Electronic Theses and Dissertations

The East Asian Monsoon system is an important dynamic of East Asian climates, affecting over one-third of the world’s population. Marginal seas within East Asia are ideal environments to study past fluctuations of monsoon intensities and durations as they are sensitive to climatic and glacio-eustatic sea level changes. This study focuses on continuous sedimentary sequences collected from three Integrated Oceanic Drilling Program Expedition 346 sites; Sites U1426 and U1427 in the Japan Sea and Site U1429 in the East China Sea. Elemental concentration (%TOC, %TN, and %CaCO₃) and stable isotope ratios (δ¹³C and δ¹⁵N) …

Benthic Foraminiferal Assemblages From Marshes And Mangroves In The Everglades (South Florida, Usa) And Their Application As Proxies For Habitat Shifts Due To Sea Level Rise, Zoe Verlaak

FIU Electronic Theses and Dissertations

This study examined benthic foraminifera from marsh and mangrove environments along the coasts of the Everglades in South Florida for their use as proxies for salinity and applied the results to assess the nature and rates of past habitat changes due to sea level rise over the last ~3400 years. Research on modern foraminiferal assemblages from the Everglades are scarce, and this is the first foraminifera-based paleoenvironmental study for this region.

The study of living assemblages examined the extent to which infaunal foraminifera bias modern and fossil assemblages, and which sediment interval should be used as a modern analog for …

Rip Current Generation, Flow Characteristics And Implications For Beach Safety In South Florida, Stephen B. Leatherman

FIU Electronic Theses and Dissertations

Rip currents are the most dangerous hazard at surf beaches. Rip currents in South Florida have previously not been studied. Beach profiles for three Florida beaches (Miami Beach, Lido Beach, Sarasota, and Pensacola Beach) and one Georgia beach (South Cumberland Island) were chosen for surveying because of their variable sand bar heights. Rip current hazard at each beach was assessed by lifeguard rip rescue and drowning statistics. A relationship was found between sand bar height, beach slope and rip current hazard.

Rip current measurements in South Florida, which involved utilizing GPS drifters, laser rangefinder and drone-imaged fluorescent tracer dye, showed …

Characterization Of The Uranium-Bearing Phases Produced By Novel Remediation Technologies For Sequestration Of Mobile Radiological Contaminants In The Hanford 200 Area Vadose Zone, Robert Michael Lapierre

FIU Electronic Theses and Dissertations

Of the many toxic chemicals released into the Hanford vadose zone over the decades of nuclear weapons production, uranium has emerged as a contaminant of significant interest. The ammonia gas injection remediation method has been identified as a promising approach towards mitigating the risks to the ecosystem by limiting the mobility of the radionuclide in the vadose zone. The remediation method was replicated using synthetic porewater solutions with a range of constituent concentrations equal to that of the Hanford 200 Area vadose zone. The uranium-bearing products of the remediation method were characterized using kinetic phosphorescence analysis for aqueous uranium, scanning …

The Effect Of Microbial Growth On The Spectral Induced Polarization Response In Hanford Vadose Zone Sediment In The Presence Of Autunite, Alejandro Garcia

FIU Electronic Theses and Dissertations

Uranium contamination of the subsurface remains a significant problem at the Department of Energy Hanford site. A series of column experiments were conducted on Hanford sediment saturated with simulated groundwater to study the effects of aqueous bicarbonate and microbial growth on the mobility of Uranium. Spectral induced polarization (SIP) measurements in the columns were conducted concurrently with pore water sampling in order to monitor changes occurring inside the sediment after the initiation of microbial growth induced by glucose injection. The microbial growth caused significant increases in the real component of the complex conductivity and is the result of ion release …

Developing Ocean Color Algorithm Using Moderate Resolution Imaging Spectroradiometer (Modis) Sensor For Shallow Coastal Water Bodies, Mohd Manzar Abbas

FIU Electronic Theses and Dissertations

This study analyses the spatial and temporal variability of chlorophyll-a in Chesapeake Bay; assesses the performance of Ocean Color 3M (OC3M) algorithm; and develops a novel algorithm to estimate chlorophyll-a for coastal shallow water. The OC3M algorithm yields an accurate estimate of chlorophyll-a concentration for deep ocean water (RMSE=0.016), but it failed to perform well in the coastal water system (RMSE=23.17) of Chesapeake Bay. A novel algorithm was developed which utilizes green and red bands of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. The novel algorithm derived the chlorophyll-a concentration more accurately in Chesapeake Bay (RMSE=4.20) than the OC3M algorithm. …

Environmental Dynamics Of Dissolved Organic Matter And Dissolved Black Carbon In Fluvial Systems: Effects Of Biogeochemistry And Land Use, J. Alan Roebuck Jr.

FIU Electronic Theses and Dissertations

Black carbon (BC) is an organic residue formed primarily from biomass burning (e.g., wildfires) and fossil fuel combustion. Until recently, it was understood that BC was highly recalcitrant and stabilized in soils over millennial scales. However, a fraction of the material can be solubilized and transported in fluvial systems as dissolved BC (DBC), which represents on average 10% of the global export of dissolved organic carbon (DOC) from rivers to coastal systems. The composition of DBC controls its reactivity, and it has been linked with a variety of in-stream processes that induce both carbon sequestration and evasion of CO₂ from …

Changes In Soil Microbial Functioning In Coastal Wetlands Exposed To Environmental Stressors And Subsidies, Shelby M. Servais

FIU Electronic Theses and Dissertations

Environmental perturbations are ubiquitous features of ecosystems and shape ecological structure and function. Climate change will alter the intensity and frequency of disturbances and expose ecosystems to novel combinations of useful inputs (subsidies) and harmful inputs (stressors). Coastal wetlands are particularly vulnerable to changing environmental conditions and are increasingly exposed to effects of interacting subsidies and stressors. In particular, the Florida Coastal Everglades, which has experienced accelerated change due to a history of water management practices, is vulnerable to new disturbances associated with climate change. The low-lying Florida Everglades faces multiple disturbances from storm surge, nutrient enrichment, and sea-level rise …

Identifying The Origins Of Volcanic Ash Deposits Using Their Chemical And Physical Compositions, Emmanuel Soto

FIU Electronic Theses and Dissertations

Recent ocean sediments collected offshore Chile by Ocean Drilling Program Leg 202 contained layers of volcanic ash of unknown origin. These deposits may have originated from sources in the Southern Volcanic Zone (SVZ) within the Andean Volcanic Belt to the east, or from explosive volcanoes in the southwestern Pacific transported by westerly prevailing winds. In this study, mineral and glass textures and compositions of Leg 202 ashes were evaluated to try to determine the sources of the ash layers. Ash fragments were imaged and analyzed for major elements using an SEM with X-Ray detector and for trace elements using LA-ICPMS. …

Paleoenvironments, Origin, And Relative Maturity Of Organic Matter In Barremian-Aptian Limestones Of The Eastern Prada Quarry, Organyà Basin, Ne Spain, Jose R. Llaguno

FIU Electronic Theses and Dissertations

This study is a multi-proxy analysis of a 30-m section of a Barremian-Aptian succession of interbedded, grayish black (N2) and black (N1) limestones from a quarry of the Sierra de Prada. Index taxa include planktic foraminifera Globigerinelloides blowi and Hedbergella sigali, which combined with δ¹³C data from Cresmina and Gorgo a Cerbara sections indicate a late Barremian to early Aptian age. The rocks are organic-rich with 0.67 - 3.10 wt% total organic carbon (TOC). A marlstone interval (~1m) at 2.24 m has a low bioturbation index (1), TOC ~6.66 wt%, framboidal pyrite, and enrichment spikes of major, …

Linking Organic Matter Dynamics To Management, Restoration, And Climate In The Florida Everglades, Peter Regier

FIU Electronic Theses and Dissertations

The Florida Everglades is a massive and highly managed subtropical wetland ecosystem, strongly influenced by anthropogenic control of freshwater distribution and highly susceptible to a changing climate, including rising sea-level and changes in temperature and rainfall. Shifting hydrologic regimes impact ecosystem function and biogeochemistry, which in turn control the sources, fate, and transport of organic matter. As a master environmental variable, it is essential to understand how organic matter dynamics will respond to changes in the balance between freshwater and saltwater associated with landscape-scale Everglades restoration efforts and climate change. The research comprising this dissertation improves current understanding of the …

A Functional Trait Approach To Examine Plant Community Dynamics In South Florida Hardwood Hammock Forests, Suresh Chandra Subedi

FIU Electronic Theses and Dissertations

The tropical hardwood forests of south Florida persist as well-drained patches of broadleaf forest separated by brackish water swamp, marsh, or pineland. In this dissertation, a functional trait approach was used to understand the structure and dynamics of these communities and their responses to abiotic and biotic variation. Twenty-seven permanent plots (20 x 20 m²) were established across the south Florida landscape, representing four sub-regions: Everglades marsh, Long Pine Key, Upper Keys, and Lower Keys. Community weighted mean trait values for four of six selected traits showed significant inter-sub-regional variation. Out of them, three traits (specific leaf area, …

Investigating The Effects Of Land-Cover Change On The Hydrologic Conditions Of A Restored Agricultural Area In Everglades National Park, Dillon Reio

FIU Electronic Theses and Dissertations

In the Florida Everglades, remodeling of natural wetlands to promote agriculture and human settlement, have profoundly altered its hydrologic regime. As a result of anthropogenic changes, many restoration programs have been initiated to restore hydrologically controlled wetland ecosystems. One such restoration project that has been ongoing for the past 27 years is the Hole-in-the-Donut restoration program in Everglades National Park. The restoration program is unique in that it utilized an unorthodox technique to restore the landscape. The viability of the restoration technique was assessed by coupling long-term hydrologic and evapotranspiration data with water chemistry analyses. Key results indicated that the …

Rip Current Formation And Beach Safety Implications For Several U.S. Atlantic Coast Beach Areas, Kathleen Michelle Fallon

FIU Electronic Theses and Dissertations

This dissertation combines seemingly different studies, which work together to describe the physical characteristics of rip current development and associated social implications at several locations. These fast-moving, concentrated flows of water travel offshore and can be found on any beach with sufficient wave action. Any event of increased wave steepness will erode a large quantity of sediment from the beach. The material deposited offshore eventually makes its way back; during this process, ocean water becomes trapped behind a shore-attached bar resulting in a ridge-and-runnel. These formations are seen at East Hampton, where rip-like currents form as concentrated water drains from …