Earth Sciences Commons^™

Interannual And Subdecadal Variability In The Nutrient Geochemistry Of The Cariaco Basin, Mary I. Scranton, Gordon T. Taylor, Robert Thunell, Claudia R. Benitez-Nelson, Frank Muller-Karger, Kent Fanning, Laura Lorenzoni, Enrique Montes, Ramon Varela, Yrene Astor

Faculty Publications

The CARIACO Ocean Time Series program has made monthly measurements of oxygen, nutrients, and carbon system parameters (∑CO2, alkalinity, pH) in the Cariaco Basin since 1996. At the same time, sediment traps have collected settling particles at four to five depths ranging from 150 to 1,200 m. The depth of the transition from oxic to anoxic conditions has fluctuated dramatically over the time series due to changes in the occurrence of Caribbean water intrusions into the deep basin. Nutrient concentrations in the deep basin have increased steadily with time in a proportion reflective of the elemental ratios in the settling …

Small Phytoplankton Drive High Summertime Carbonand Nutrient Export In The Gulf Of California And Eastern Tropical North Pacific, Viena Puigcorbé, Claudia R. Benitez-Nelson, Pere Masqué, Elisabet Verdeny, Angelicque E. White, Brian N. Popp, Fredrick G. Prahl, Phoebe J. Lam

Faculty Publications

Summertime carbon, nitrogen, and biogenic silica export was examined using 234Th:238U disequilibria combined with free floating sediment traps and fine scale water column sampling with in situ pumps (ISP) within the Eastern Tropical North Pacific and the Gulf of California. Fine scale ISP sampling provides evidence that in this system, particulate carbon (PC) and particulate nitrogen (PN) concentrations were more rapidly attenuated relative to 234Th activities in small particles compared to large particles, converging to 1–5 µmol dpm−1 by 100 m. Comparison of elemental particle composition, coupled with particle size distribution analysis, suggests that small particles are major contributors to …

Detrital Zircon Analysis Of The Taza-Guercif Basin And The Adjacent Rif And Middle Atlas Mountains Of Morocco And X-Ray Fluorescence Chemofacies Analysis Of The Maness Shale Of East Texas, Jonathan Richard Pratt

Theses and Dissertations

The research in this compilation encompasses three studies leveraging quantitative chemical analyses to interpret the sedimentary record to reconstruct geologic history. The first study surveys the detrital zircon U-Pb and zircon fission-track geochronology of the sedimentary Cretaceous Ketama and Tisiren units of the Rif Mountains, and the Bou Rached sandstones of the Middle Atlas Mountains. All analyzed samples contain a population of Mesoproterozoic crystallization ages formerly unknown to northwest Africa. Possible sources for these ages include the Avalonian terranes now present on the northeastern seaboard of North America, and/or zircons derived from the Amazonian craton and preserved in the Pan-African …

On The Influence Of Ionic Strength On Radium And Strontium Sorption To Sandy Loam Soils, Brian A. Powell, Todd Miller, Daniel I. Kaplan

Journal of the South Carolina Academy of Science

Models which can estimate environmental transport of radioactive contaminants in natural and engineered systems are required to 1) deploy effective remediation strategies for contaminated sites, 2) design waste repositories for future waste streams, and 3) ensure protection of human and environmental health in all cases. These models require accurate transport parameters in order to correctly predict how these contaminants will move in the subsurface. This work aimed to determine more accurately the distribution coefficients for radium and strontium sorption to Savannah River Site (SRS) soils. Radium and strontium sorption to the soils was found to be highly dependent upon ionic …

3-D Numerical Simulation Of Carbon Dioxide Injection Into The South Georgia Rift Basin For Geologic Storage, Daniel Eric Taylor Brantley

Theses and Dissertations

This study numerically simulated the injection of supercritical phase CO2 into the South Georgia Rift (SGR) basin to evaluate the feasibility and efficacy of long term geologic storage. The injection simulation modeling was divided into two phases. During phase one of the modeling, very little geologic and reservoir dynamics data was known about the SGR basin. Due to lack of basin data, an equilibrium model was used to estimate the initial hydrostatic pressure, temperature and salinity gradients that represent our study area. For the equilibrium model, the USGS SEAWAT program was used and for the CO2 injection simulation, TOUGH2-ECO2N was …

Complexity In Overmarsh Circulation, Jessica Chassereau Sullivan

Theses and Dissertations

Overmarsh circulation is highly complex with variations in current direction over very short timescales and flowpaths that differ substantially between flood and ebb cycles. Understanding such flow complexities in salt marshes is important because they inherently impact the distribution of sediment, larvae and nutrients throughout the marsh, and hence, the ecogeomorphic feedbacks that control landscape evolution. The purpose this Ph.D. research is to quantitatively evaluate the effects of salt marsh topography on overmarsh circulation in a Georgia salt marsh. This dissertation is comprised of three parts. First, digital elevation models (DEMs) were compared to characterize how well airborne lidar (light …

Proxy Development And Application For Reconstructing The Surface Ocean Carbonate System, Brittney J. Marshall

Theses and Dissertations

Over the last two centuries, human activities have led to an unprecedented rate of carbon input into the atmosphere and oceans resulting in an alarmingly rapid decline in surface ocean pH, a process referred to as ocean acidification (OA). This process is leading to an observed decline in the carbonate ion concentrations ([CO3 2-]) in seawater – an ion that a large number of marine organisms (e.g. corals, foraminifera) utilize to secrete their skeletons and shells. The ability to identify past ocean acidification events using the marine sedimentary record can shed light on future impacts of the modern OA dilemma. …

Modeling Mussel Mortality: Investigating The Importance Of Swash And The Potential Implications Of Changing Wave Environments, Shadow Leigh Gulledge

Theses and Dissertations

Rising sea level and increases in temperature are causing biogeographic shifts in intertidal zones and can also lead to shifts in the local vertical zonation of organisms due to changes in body temperature during aerial exposure during low tide. Swash is an important determinant of aerial body temperatures, and vulnerability of intertidal zones to changes in climate could potentially depend on how much and how often animals are cooled by waves. While wave heights (and thus swash) are generally expected to increase with climate change, anthropogenic physical structures, such as breakwaters and wave energy converters, can decrease wave height and …

Remote Sensing Satellite Image Acquisition Planning: Framework, Methods And Application, Shufan Liu

Theses and Dissertations

This dissertation explores the theories and methods of satellite remote sensing image acquisition planning within a spatial temporal context. For many time sensitive applications, such as disaster emergency response, timely acquisition of critical information is the key to intelligent and effective decision making. Remote sensing plays an important role in information collection for these time sensitive applications. Imagery collected from hundreds of remote sensing satellite sensors offer accurate, frequent and almost instantaneous data covering the Earth in a relatively short time. However, determining which satellite sensors can provide an appropriated kind of imageries during a restricted collection window for the …

The Geologic Implications Of The Factors That Affected Relative Sea-Level Positions In South Carolina During The Pleistocene And The Associated Preserved High-Stand Deposits, William Richardson Doar Iii

Theses and Dissertations

This work utilizes the current understanding of South Carolina geology to provide a stratigraphic review of the late-Pliocene and Pleistocene marine deposits. Almost two centuries of recorded geological study includes geomorphic and stratigraphic units that were described, proposed, revised, abandoned, and revived. Along with the history of the age assignments, changes in geological time scales, and the changes in the understanding of geological concepts, this review is necessary because two concurrent and conflicting stratigraphies exist for late-Pliocene and Pleistocene marine sediments that record multiple sea-level transgressions that were more often destructive than constructive. The result, when tested against existing geological …

Temporal Constraints On Holocene Initiation And Termination Of Mound Development At An Episodic Gas Hydrate And Cold Seep System, Woolsey Mound, Northern Gulf Of Mexico, Nathan Robinson

Theses and Dissertations

Woolsey Mound is a thermogenic gas hydrate and cold seep system in the deepwater (900m) Gulf of Mexico. A set of sub-bottom seismic profiles acquired at MC-118 Woolsey Mound provide decimeter-scale vertical resolution of the upper ~50m of the subsurface throughout the lease block. Integration of these data with radiocarbon, lithostratigraphic, and biostratigraphic data from shallow gravity cores provides the basis for detailed interpretation of the mound evolution within the last 12,000 years. Uniform sedimentation during the Last Glacial Maximum and following changes in sediment distribution over MC-118 suggests modern mound activity did not begin until at least ~12ka. Development …

Climate-Induced Changes In The Germination Phenology Of Boechera Stricta, Samuel Johnson

Theses and Dissertations

Climate change is having demonstrable, worldwide impacts on ecological systems in ways that have modified aspects of organism behavior. Plant phenologies have responded to warmer temperatures in a variety of ways that may have implications for long-term species survival. How germination phenology changes in response to warmer climate is a largely unexplored question yet the ability of a plant to advance or delay germination in unfavorable conditions is critical for survival. Knowing the relative success and timing of germination under different climate regimes is important in understanding whether species can keep pace with the rate of climate change via migration …

Investigations Of Potential Microbial Methanogenic And Carbon Monoxide Utilization Pathways In Ultra-Basic Reducing Springs Associated With Present-Day Continental Serpentinization: The Tablelands, Nl, Can, P. L. Morrill, W. J. Brazelton, L. Kohl, A. Rietze, S. M. Miles, H. Kavanagh, M. O. Schrenk, S. E. Ziegler, Susan Q. Lang

Faculty Publications

Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. …

Tectonic Studies Of The Atlantic Margin In The Southeastern United States, Andrew C. Pollack

Theses and Dissertations

Reanalysis of published seismic and well data from the South Georgia Embayment provides important new constraints on the geologic structure and evolution of the Eastern North American margin. A lower Paleozoic stratigraphic section (Silurian to Devonian) sampled in offshore wells drilled in the late 1970’s, can be correlated continuously along the entire ~250 km N-S length of the BA-3 profile acquired in 1989. Other than gentle warping and minor fault offsets, this Paleozoic section is essentially undeformed, precluding both Paleozoic contractional deformation associated with Appalachian orogeny, or subsequent Mesozoic extensional deformation and magmatism associated with continental rifting and formation of …

Garzón Massif Basement Tectonics: A Geopyhysical Study, Upper Magdalena Valley, Colombia, Kadir Baris Bakioglu

Theses and Dissertations

The mechanics and kinematics of basement tectonic uplifts, such as the Laramide Rocky Mountain orogeny, remain poorly understood and controversial. The debate continues in part because of the limited number of well-documented present day analogs. The Garzón Massif rising between the Upper Magdalena Valley and the Llanos Basin of Colombia is an active basement uplift with well, seismic, gravity, and magnetic data available. In the past 10 Ma, PreCambrian age granitic rocks of the Garzón Massif have been uplifted and displaced against Cretaceous and Tertiary sediments of the Upper Magdalena Valley along the Garzón fault.

Aerogravimetric data calibrated by well …

Channel Properties Of Fluvial-Tidal Transition, Santee River, Sc, Kyungho Jeon

Theses and Dissertations

A range of studies shows that terrestrial and tidal channel dimensions increase in the downstream direction, transitioning seaward from a power function of discharge to an exponential function of distance from the coast. There are also an increasing number of studies on tidal hydrodynamics and sedimentology in channel reaches where river and tidal flows meet. However, there is a dearth of information on the channel form in fluvial-tidal transition, and therefore we have little understanding of what constitutes the fluvial-tidal transition channel, or channel reach. The Santee River in South Carolina is a gently sloping (average 10-5) coastal plain river …

Flow Dynamics In The Transition Zone From Estuarine Tidal To Fluvial Regime In The Santee River, Sc, Usa, Legna M. Torres-Garcia

Theses and Dissertations

Estuaries are important systems that link fresh, inland waters to oceanic salt water, where they act to deliver large amounts of nutrients, sediments and pollutants into the ocean. Traditionally, the study of estuarine systems has been marked by difficulty owing to the complex hydrodynamics influenced by strong bathymetric changes, changes in tidal range, intricate geomorphology, among other factors; thus beginning to unravel the complexities of estuarine hydrodynamics will help to illuminate the nature of estuaries as well as to provide a foundation for their further study. In this study I focus on the transition zone from tidal to fluvial regime, …

Genes Mediating Cardiac Remodeling During Pregnancy And The Early Post-Partum-Period In Mice, Esam Aljrbi

Theses and Dissertations

The female heart undergoes adaptive remodeling during pregnancy to compensate for the increased hemodynamic load imposed by the developing fetus. However, unlike a similar adaptive process which occurs under pathological conditions (such as hypertension and valvular heart disease) the cardiac changes observed during hypertrophy associated with pregnancy are reversible. The goal of this study is to identify changes in gene expression associated with pregnancy-induced hypertrophy. We tested the hypothesis that pregnancy-induced physiological hypertrophy has a unique genetic signature, likely due to altered hormone levels, which supports and promotes reversible remodeling. Comparing the gene expression profile associated with physiological remodeling with …

P‐Nexfs Analysis Of Aerosol Phosphorus Delivered To The Mediterranean Sea, Amelia F. Longo, Ellery D. Ingall, Julia M. Diaz, Michelle Oakes, Laura E. King, Athanasios Nenes, Nikolaos Mihalopoulos, Kaliopi Violaki, Anna Avila, Claudia R. Benitez-Nelson, Jay Brandes, Ian Mcnulty, David J. Vine

Faculty Publications

Biological productivity in many ocean regions is controlled by the availability of the nutrient phosphorus. In the Mediterranean Sea, aerosol deposition is a key source of phosphorus and understanding its composition is critical for determining its potential bioavailability. Aerosol phosphorus was investigated in European and North African air masses using phosphorus near‐edge X‐ray fluorescence spectroscopy (P‐NEXFS). These air masses are the main source of aerosol deposition to the Mediterranean Sea. We show that European aerosols are a significant source of soluble phosphorus to the Mediterranean Sea. European aerosols deliver on average 3.5 times more soluble phosphorus than North African aerosols …

Production And Transformation Of Dissolved Neutral Sugars And Amino Acids By Bacteria In Seawater, L. Jørgensen, O. J. Lechtenfeld, Ronald Benner, M. Middleboe, C. A. Stedmon

Faculty Publications

Dissolved organic matter (DOM) in the ocean consists of a heterogeneous mixture of molecules, most of which are of unknown origin. Neutral sugars and amino acids are among the few recognizable biomolecules in DOM, and the molecular composition of these biomolecules is shaped primarily by biological production and degradation processes. This study provides insight into the bioavailability of biomolecules as well as the chemical composition of DOM produced by bacteria. The molecular compositions of combined neutral sugars and amino acids were investigated in DOM produced by bacteria and in DOM remaining after 32 days of bacterial degradation. Results from bioassay …

A Quantitative Analysis Of White-Tailed Deer Harvest Across States And Counties, Rebecca Lynne Cain

Theses and Dissertations

White-tailed deer (Odocoileus virginianus) have gone from locally extirpated to overabundant in many areas in the United States since the early 1900s. Ecosystems with chronically overabundant populations experience many disastrous effects resulting from the selective browsing behavior of deer. White-tailed deer are managed at the state level resulting in different management strategies, harvest data collection, and deer management goals between states. However recreational hunting is the primary tool used by wildlife agencies to control population growth. As such, it is beneficial to understand the influence each regulatory variable has on white-tailed deer harvest.

For this research, I compiled historical harvest …

Hydrological Influences On Ecological Zonation In A Salt Marsh Tidal Creek Basin: Crab Haul Creek, South Carolina, Usa, Elizabeth Madsen

Theses and Dissertations

Ecological zones in a salt marsh are controlled by many factors, including hydroperiod, elevation, soil salinity, groundwater flow, competition, and nutrient/oxygen availability. The primary driving factor(s) are still debated, but most models of zonation consider elevation or hydroperiod as the key factor. This project is designed to gather high-resolution aerial images from a helium balloon kite (Helikite) to improve our understanding of the influence of hydroperiod on zonation. The Helikite was used to capture aerial photographs of Crab Haul Creek Basin, the most landward salt marsh basin in North Inlet, South Carolina. Near-IR photographs were taken from 75-100m altitude to …

Seismic Characterization Of The J-Reflector Near The Meizoseismal Area Of The 1886 Charleston Earthquake For Lithologic Constraint, Craig Cunningham

Theses and Dissertations

Investigations into the relationship between geologic structure and seismicity in and around the meizoseismal area of the 1886 Charleston earthquake have been ongoing since the 1970s. Seismic reflection profiles collected in this area display a prominent, laterally continuous, high amplitude, low frequency, two cycle reflection at ~0.7-1.2 s TWT, termed the "J" reflector, which has been correlated with Lower to Middle Jurassic tholeiitic basalt flows encountered in the Clubhouse Crossroads wells. The "J" reflector was also extended offshore onto the continental shelf. Recent reevaluation of sub Coastal Plain wells within the South Georgia Rift (SGR) Basin, including wells around the …

Comparative Recharge Rates Of Isolated And Riverine Wetlands, Chenille Hargrove Williams

Theses and Dissertations

Isolated wetlands have a slightly depressed topography surrounded by an upland area. There is no direct surface water connection, as with riverine wetlands; however, there is a groundwater connection that allows isolated wetlands to have similar hydrologic functions to riverine wetlands. This study sought to compare surficial aquifer groundwater recharge rates of several isolated and riverine wetlands in the Coastal Plain of the Carolinas by evaluating soil characteristics, water table fluctuations, and precipitation from January 2012 - September 2012. Data analysis indicated no significant difference in mean recharge rates between the isolated and riverine wetlands at each study site. Whereas …

Spatial And Seasonal Variability Of Dissolved Organic Matter In The Cariaco Basin, Laura Lorenzoni, Gordon T. Taylor, Claudia R. Benitez-Nelson, Dennis A. Hansell, Enrique Montes, Robert Masserini, Kent Fanning, Ramón Varela, Yrene Astor, Laurencia Guzmán, Frank E. Muller-Karger

Faculty Publications

[1] Dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) were measured monthly at the CARIACO Time Series station (10°30′N, 64°40′W) in the southeastern Caribbean Sea between 2005 and 2012. Marked seasonal variability in DOC concentrations was observed, with lower values (~66 µM) in the upper water column (<75 >m) during the upwelling season (December–April) due to the injection of cool, DOC‐impoverished Subtropical Underwater from the Caribbean Sea. During the rainy season (May–November) waters were stratified and upper layer DOC concentrations increased to ~71 µM. Interannual variability in surface (1 m) concentrations of DOC was also observed in response to …

Biogenic Nitrogen Gas Production At The Oxic–Anoxic Interface In The Cariaco Basin, Venezuela, E. Montes, M. A. Altabet, F. E. Muller-Karger, M. I. Scranton, R. C. Thunell, Claudia R. Benitez-Nelson, L. Lorenzoni, Y. M. Astor

Faculty Publications

Excess nitrogen gas (N2xs) was measured in samples collected at six locations in the eastern and western sub-basins of the Cariaco Basin, Venezuela, in September 2008 (non-upwelling conditions) and March 2009 (upwelling conditions). During both sampling periods, N2xs concentrations were below detection in surface waters, increasing to ~ 22 μmol N kg−1 at the oxic–anoxic interface ([O2] < ~ 4 μmol kg−1, ~ 250 m). Below the oxic–anoxic interface (300–400 m), the average concentration of N2xs was 24.7 ± 1.9 μmol N kg−1 in September 2008 and 27.5 ± 2.0 μmol N kg−1 in March 2009, i.e., N2xs concentrations within this depth interval were ~ 3 μmol N kg−1 higher (p < 0.001) during the upwelling season compared to the non-upwelling period. These results suggest that N-loss in the Cariaco Basin may vary seasonally in response to changes in the flux of sinking particulate organic matter. We attribute the increase in N2xs concentrations, or N-loss, observed during upwelling to: (1) higher availability of fixed nitrogen derived from suspended and sinking particles at the oxic–anoxic interface and/or (2) enhanced ventilation at the oxic–anoxic interface during upwelling.

Drought Indices In Decision-Making Process Of Drought Management, Ekaterina Negodyaeva Altman

Theses and Dissertations

Drought indices are one of the most important elements of an effective drought monitoring and early warning system. They help to characterize drought and guide appropriate responses to reduce drought impacts. Drought indicators are more useful than raw data in decision-making process, even though each index has specific use and limited by its strengths and weaknesses. The literature review showed the evaluation of drought conditions by decision-makers as an important issue, but so far no research has been done to understand how decision-makers use diverse and often conflicting values of drought indices to make drought declarations. This research studies how …

Geochemical Source Components In Seafloor Lavas In The Aleutian Back-Arc, Max Thomas Siegrist

Theses and Dissertations

Whole-rock compositions of seafloor lavas are used to constrain the processes and source characteristics contributing to the formation of geochemically distinctive, primitive magma types located in the Aleutian back-arc. Samples were dredged primarily from small volcanic cones on the seafloor, located between the emergent volcanoes and in the back-arc up to 60 km from the volcanic front. Compositions vary from basalt to dacite, with 48-70 % SiO₂ and 4-13 % MgO. Nearly 30% of the samples are primitive, with Mg/Mg+Fe >0.60. Most primitive samples are basalts, which fall into two groups, based on minor and trace element abundances. Low/med-K …

Volcanic And Tectonic Processes Along Anomalous Mid-Ocean Ridges, Julia Kathryn Howell

Theses and Dissertations

The morphological and structural characteristics of the global spreading ridge system are systematically related to spreading rate and magma supply (e.g. Macdonald, 1982). Because intermediate spreading-rate ridges (ISRs) spreading between 60 and 80 mm/yr have characteristics of both fast and slow spreading ridges, they are ideal environments to study the differences controlling upper crustal accretion. We examine the distribution of seamounts along spreading ridges to understand the relationship between seamount volcanism and axial morphology along four ISRs: the Juan de Fuca Ridge (JdFR), the Galápagos Spreading Centers (GSC), the Southeast Indian Ridge (SEIR), and the Eastern Lau Spreading Centers (ELSC). …

Benthic Boundary Layer Processes: Bedform Evolution And Bottom Turbulence, Timothy Robert Nelson

Theses and Dissertations

Bedform roughness, caused by ripples on the seabed, plays an important role in controlling sediment dynamics in the nearshore region. In this dissertation, the temporal and spatial evolution of ripples from two field sites located in the South Atlantic Bight, offshore Long Bay, SC and Georgia are used to relate wave-induced ripple geometry (wavelength and orientation) to near bed directional wave velocities. 2-D spectral analysis techniques were developed to automate detection of ripple wavelength, direction, and irregularity. This analysis showed that magnitude, direction, and duration of wave forcing controls ripple geometry and irregularity. During highly energetic events, ripple geometry changes …