Earth Sciences Commons^™

Mantle Heterogeneity From The Mantle Plume Perspective: Sources Vs. Processes, Paul Béguelin

Theses and Dissertations

Oceanic island basalts (OIB) which are derived from mantle plumes sample a compositionally heterogeneous mantle, as revealed by their radiogenic isotope systematics. Isotope compositions recurring in distinct hotspots have been used to characterize the composition and heterogeneity of the mantle as well as the thermochemical structure of upwelling plumes, with the assumption that the isotope composition of erupted lavas directly reflects that of their mantle source.

Here I test how source transport, melting and hybridization in the upper mantle through space and time control the expression of deep mantle sources in erupted lavas. This work is focused on the Azores …

Mercury Cycling In The North Pacific Subtropical Gyre As Revealed By Mercury Stable Isotope Ratios, Laura C. Motta, Joel D. Blum, Marcus W. Johnson, Blaire P. Umhau, Brian N. Popp, Spencer J. Washburn, Jeffrey C. Drazen, Claudia R. Benitez-Nelson, Cecelia C. S. Hannides, Hilary G. Close, Carl H. Lamborg

Faculty Publications

The oceans are an important global reservoir for mercury (Hg), and marine fish consumption is the dominant human exposure pathway for its toxic methylated form. A more thorough understanding of the global biogeochemical cycle of Hg requires additional information on the mechanisms that control Hg cycling in pelagic marine waters. In this study, Hg isotope ratios and total Hg concentrations are used to explore Hg biogeochemistry in oligotrophic marine environments north of Hawaii. We present the first measurements of the vertical water column distribution of Hg concentrations and the Hg isotopic composition in precipitation, marine particles, and zooplankton near Station …

Short-Term Effect Of Simulated Salt Marsh Restoration By Sand-Amendment On Sediment Bacterial Communities, François Thomas, James T. Morris, Cathleen Wigand, Stefan M. Sievert

Faculty Publications

Coastal climate adaptation strategies are needed to build salt marsh resiliency and maintain critical ecosystem services in response to impacts caused by climate change. Although resident microbial communities perform crucial biogeochemical cycles for salt marsh functioning, their response to restoration practices is still understudied. One promising restoration strategy is the placement of sand or sediment onto the marsh platform to increase marsh resiliency. A previous study examined the above- and below-ground structure, soil carbon dioxide emissions, and pore water constituents in Spartina alterniflora-vegetated natural marsh sediments and sand-amended sediments at varying inundation regimes. Here, we analyzed samples from the …

Growth Kinetics, Carbon Isotope Fractionation, And Gene Expression In The Hyperthermophile Methanocaldococcus Jannaschii During Hydrogen-Limited Growth And Interspecies Hydrogen Transfer, Begüm D. Topçuog˘ Lu, Cem Meydan, Tran B. Nguyen, Susan Q. Lang, James F. Holden

Faculty Publications

Hyperthermophilic methanogens are often H2 limited in hot subseafloor environments, and their survival may be due in part to physiological adaptations to low H2 conditions and interspecies H2 transfer. The hyperthermophilic methanogen Methanocaldococcus jannaschii was grown in monoculture at high (80 to 83 M) and low (15 to 27 M) aqueous H2 concentrations and in coculture with the hyperthermophilic H2 producer Thermococcus paralvinellae. The purpose was to measure changes in growth and CH4 production kinetics, CH4 fractionation, and gene expression in M. jannaschii with changes in H2 flux. Growth and cell-specific CH4 production rates of M. jannaschii decreased with decreasing …

Endolithic Microbial Carbon Cycling In East Antarctica, Natalie Tyler

Theses and Dissertations

Microbes adapt to inhospitable conditions by colonizing niches that protect them from severe environmental conditions, making them model organisms in the search for life on other planets. Endoliths are globally ubiquitous microbes that colonize structural cavities within rocks, which protect them from environmental stressors while maintaining access to nutrition and light sources. Despite harsh katabatic winds, extreme temperature fluctuations, harmful UV radiation and exposure to desiccation, endolithic communities have been observed in Antarctica. Previous studies have found viable and abundant microbial biomass through microscopy and the addition of isotopic labels. However, due to the slow metabolic activity of these microbes, …

Water Systematics Of Samoan Peridotite Xenoliths, Aaron Wolfgang Ashley

Theses and Dissertations

Water influences geodynamic processes such as melting, deformation and rheology. Yet its distribution in the oceanic upper mantle is primarily known indirectly from melt inclusions and glasses of erupted mantle melts (i.e. MORB and OIB). To constrain the mechanisms influencing the distribution of water in the mantle, we analyzed 15 peridotite xenoliths from Savaiʻi and 2 dunite xenoliths from Taʻū (Samoa) for water concentrations (by polarized FTIR) and major/trace elements. Savaiʻi peridotites are among the most melt depleted oceanic xenoliths recovered (degrees of melt depletion ≥15%). They show strong evidence of transient metasomatism by both carbonatite and silicate melts, with …

Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen

Faculty Publications

Building on the synthesis of carbon reservoirs in Earth's subsurface, this chapter focuses on the forms, cycling, and fate of the carbon supporting microbial life in the terrestrial and marine subsurface. As the subsurface is estimated to host a vast reservoir of life on Earth, identifying the carbon compounds that life uses for energy and growth is key to understanding ecosystem functioning in the past and at present, and also for extrapolating these findings to the search for life in the universe. This chapter highlights advances in quantifying small carbon compounds, measuring rates of carbon turnover, and the fate of …

A Time Series Of Water Column Distributions And Sinking Particle Flux Of Pseudo-Nitzschia And Domoic Acid In The Santa Barbara Basin, California, Blaire P. Umhau, Claudia R. Benitez-Nelson, Clarissa R. Anderson, Kelly Mccabe, Christopher Burrell

Faculty Publications

Water column bulk Pseudo-nitzschia abundance and the dissolved and particulate domoic acid (DA) concentrations were measured in the Santa Barbara Basin (SBB), California from 2009–2013 and compared to bulk Pseudo-nitzschia cell abundance and DA concentrations and fluxes in sediment traps moored at 147 m and 509 m. Pseudo-nitzschia abundance throughout the study period was spatially and temporally heterogeneous (L⁻¹ to 3.8 × 10⁶ cells L⁻¹, avg. 2 × 10⁵ ± 5 × 10⁵ cells L⁻¹) and did not correspond with upwelling conditions or the total DA (tDA) concentration, which was also spatially …

Using Satellite Remote Sensing To Study The Impact Of Climate And Anthropogenic Changes In The Mesopotamian Marshlands, Iraq, Reyadh Albarakat, Venkat Lakshmi, Compton J. Tucker

Faculty Publications

The Iraqi Marshes in Southern Iraq are considered one of the most important wetlands in the world. From 1982 to the present, their area has varied between 10,500 km² and 20,000 km². The marshes support a variety of plants, such as reeds and papyrus, and are home to many species of birds. These marshes are Al-Hammar, Central or Al-Amarah, and Al-Huwaiza. Freshwater supplies to the marshes come from the Tigris and Euphrates rivers in Iraq and from the Karkha River from Iran. For this analysis, we used the Land Long-Term Data Record Version 5 (LTDR V5) Normalized …

Serpentinization: Connecting Geochemistry, Ancient Metabolism And Industrial Hydrogenation, Martina Preiner, Joana C. Xavier, Fliipa L. Sousa, Verena Zimorski, Anna Neubeck, Susan Q. Lang, H. Chris Greenwell, Karl Kleinermanns, Harun Tüysüz, Tom M. Mccollom, Nils G. Holm, William F. Martin

Faculty Publications

Rock–water–carbon interactions germane to serpentinization in hydrothermal vents have occurred for over 4 billion years, ever since there was liquid water on Earth. Serpentinization converts iron(II) containing minerals and water to magnetite (Fe₃O₄) plus H₂. The hydrogen can generate native metals such as awaruite (Ni₃Fe), a common serpentinization product. Awaruite catalyzes the synthesis of methane from H₂ and CO₂ under hydrothermal conditions. Native iron and nickel catalyze the synthesis of formate, methanol, acetate, and pyruvate—intermediates of the acetyl-CoA pathway, the most ancient pathway of CO₂ fixation. Carbon monoxide dehydrogenase …

Using Geological Facies To Estimate Chromate Sorption To Soils, Victoria Smith, Daja Scurlock, Chauntilena Butler, Eddie Hollins, Kennedy Smith, Tim Spearman, Christina Fulghum, John Dickson, Daniel I. Kaplan, Miles Denham, Garriet Smith

Journal of the South Carolina Academy of Science

Quantifying the extent to which contaminant metals bind to subsurface soils is important for risk assessment, the tendency for a contaminant to migrate, and developing environmental remediation strategies. Unfortunately, subsurface soils vary widely in their composition, which in turn affect their tendency to bind metals. The hypothesis of this study was predicated on how a better understanding of geological facies would reduce uncertainty associated with predicting contaminant metal sorption. Facies are layers of sediment deposited in the subsurface due to similar depositional conditions, including energy of an overlying waterway. As such, facies are expected to have similar assemblages of minerals, …

Unveiling The Enigma Of Refractory Carbon In The Ocean, Nianzhi Jiao, Ruanhong Cai, Qiang Zheng, Kai Tang, Jihua Liu, Fangkue Jiao, Douglas Wallace, Feng Chen, Chao Li, Rudolf Amann, Ronald Benner, Farooq Azam

Faculty Publications

No abstract provided.

Deeply-Sourced Formate Fuels Sulfate Reducers But Not Methanogens At Lost City Hydrothermal Field, Susan Q. Lang, Gretchen L. Früh-Green, Stefano M. Bernasconi, William J. Brazelton, Matthew O. Schrenk, Julia M. Mcgonigle

Faculty Publications

Hydrogen produced during water-rock serpentinization reactions can drive the synthesis of organic compounds both biotically and abiotically. We investigated abiotic carbon production and microbial metabolic pathways at the high energy but low diversity serpentinite-hosted Lost City hydrothermal field. Compound-specific 14C data demonstrates that formate is mantle-derived and abiotic in some locations and has an additional, seawater-derived component in others. Lipids produced by the dominant member of the archaeal community, the Lost City Methanosarcinales, largely lack 14C, but metagenomic evidence suggests they cannot use formate for methanogenesis. Instead, sulfate-reducing bacteria may be the primary consumers of formate in Lost City chimneys. …

Hydrothermal Stamp On The Oceans, Susan Q. Lang

Faculty Publications

The composition of the oceans is altered by hydrothermal circulation. These chemical factories sustain microbial life, which in turn alters the chemistry of the fuids that enter the ocean. A decade of research details this complex interchange.

Re-Evaluation Of The Extent And Tectonic History Of The Helena Banks Fault Zone, Offshore South Carolina, Ahmet Postaagasi

Theses and Dissertations

The Helena Banks Fault Zone (HBFZ), first identified in the early 1980’s offshore Charleston, S.C., was originally interpreted to be a major, high-angle, basin-bounding normal fault associated with Mesozoic rifting. Subsequent work suggests that (1) Mesozoic rift basins are not present on the continental shelf of South Carolina, (2) the HBFZ originated as a strike-slip fault within Paleozoic sedimentary rocks of the Suwannee Basin sequence, (3) a mafic intrusion inferred from aeromagnetic data is coincident with a broadly circular zone of highly-complex faulting along the north-eastward continuation of the HBFZ where (4) up to 300 m of local relief can …

The Impact Of Upland Development And Marsh Width On Groundwater Composition In Estuarine Tidal Creeks In The Southeastern Coastal United States, Meghan Shanahan

Theses and Dissertations

Coastal upland development has been shown to negatively impact surface water quality in tidal creeks along the southeastern coastal United States, but the impact of development on groundwater quality is not well understood. Increases in impervious cover associated with development has the potential to increase groundwater contamination as well as reduce fresh rainwater infiltration into the subsurface, which may decrease discharge of fresh groundwater to the estuary. We hypothesized that groundwater nutrient concentrations and salinity ranges would be higher in developed watersheds than in undeveloped watersheds.

Groundwater discharging from coastal uplands often travels through salt marshes before discharging to tidal …

Salt Tectonism In The Carolina Trough, Ceren Postaagasi

Theses and Dissertations

The Carolina Trough is a major linear sedimentary basin along the eastern continental margin of North America which formed as a result of tectonic and thermal subsidence during continental rifting in Mesozoic time (Hutchinson et al., 1982). The Carolina Trough is unique along the southeastern U.S. margin where the only known evaporite deposits are found, and this salt basin may reserve large amounts of oil and gas (Carpenter & Amato, 1992). Therefore, analysis of 2D multichannel seismic reflection surveys that were conducted in the Mid-South Atlantic Ocean in 1982 plays an important role in Petroleum industry. In addition, current interpretations …

Impacts Of Drainage Systems On Stormwater Hydrology: Rocky Branch Watershed, Columbia, South Carolina, Logan Ress

Theses and Dissertations

The effects of urbanization and associated land use changes, specifically increases in impervious surfaces, have long been the focal point of urban hydrologic research. However, studies and calculations that consider impervious surfaces alone do not encompass all factors that influence urban hydrologic response. Artificial structures such as storm sewer (SS) systems and road networks increase rates of stormwater conveyance, yet these artificial networks are rarely considered in computations of drainage densities and associated hydrologic alterations. This study examines several hydrologically relevant descriptors that can be used to better understand the impact of urbanization on small watersheds. Rainfall and stormflow data …

Effectiveness Of Conventional And Lid Stormwater Management Approaches With Swmm Modeling: Rocky Branch Watershed, Columbia, Sc, John M. Williams

Theses and Dissertations

Increases in percent impervious area and storm-sewer densities in an urbanized watershed lead to increased flood risk in urban areas. Conventional flood-risk management strategies such as detention ponds and low impact development (LID) can reduce peak flows. Research is needed to resolve questions about which strategy is best-suited for stormwater management under various schemes of sizing, distribution, and cost. Conventional and LID strategies differ in associated costs and benefits in addition to effectiveness and location feasibility. Previous research suggests that conventional strategies require less initial investment for design and construction, though LID is more cost effective in the long-term due …

The Sedimentary Record Of Eocene Deformation In The Interior Of The Southern Canadian Cordillera, Erica May Rubino

Theses and Dissertations

Eocene sedimentary strata exposed in the interior of the southern Canadian Cordillera (SCC) in British Columbia (BC) and northernmost Washington (WA) record a poorly understood history of extension-related deformation in the hinterland of the orogen. Today these strata are exposed in isolated, distinct outcrop belts, although the nature of the original basin(s) is unknown. We examined 650 m of Eocene strata, analyzed 2,995 detrital zircons for uranium-lead (U-Pb) ages, and measured 67 detrital zircons for Hf isotope systematics in an effort to better understand the physiography of the SCC during this time period. Eocene strata consist of clast- and matrix-supported …

Organic Acids And Amino Acids In Serpentinization Related Fluids From The Atlantis Massif, Nicholas Camper

Theses and Dissertations

Serpentinization is a low temperature, low pressure process that occurs when water reacts with ultramafic rocks. Fluids that have interacted with serpentinites have elevated concentrations of hydrogen and reduced carbon species that can fuel chemolithoautotrophy. International Ocean Discovery Program Expedition 357 drilled a series of boreholes into the Atlantis Massif with the goal of investigating how serpentinization impacts carbon cycling and sustains life in the subseafloor. Bottom water samples (CTD), fluids flushed from the boreholes during drilling (Rock Drill), and fluids that were trapped in the liners of the cores (Liner fluids) were collected. The changes and distributions of organic …

Classifying The Woody Vegetation Community Of Wade Ponds In Colleton County, South Carolina, Wade Biltoft

Theses and Dissertations

Wetland habitats are some of the most biodiverse ecosystems in the world, varying in both physical and biological characteristics. Geographically isolated wetlands are particularly important to the landscape due to their role in the hydrological cycle and as local centers for biodiversity. In parts of the coastal plain of South Carolina, there are geographically isolated wetlands found in concentrated groups with distinctive size, shape, and distribution. Despite their unique appearance and distribution, these wetlands have been scarcely researched or investigated. This project seeks to explore the plant communities that are contained within these ponds in order to understand their composition …

Assessment Of Upper Cretaceous Strata For Offshore Co2 Storage: Southeastern United States, Khaled F. Almutairi

Theses and Dissertations

This is the first assessment of Upper Cretaceous strata for offshore CO2 storage resources in the southeastern United States outer continental shelf. This research focuses on Upper Cretaceous geological units using legacy industry 2-D seismic reflection and well data. It provides an integrated description and reliable subsurface evaluation of Upper Cretaceous potential storage reservoirs. In addition, it provides a detailed evaluation on how rock porosities and permeabilities are distributed across the Upper Cretaceous strata restricted to the South Georgia Embayment (SGE). Structure and thickness (isochore) maps were generated for the main potential reservoirs and seals on a regional and local …

Modeled Co2 Emissions From Coastal Wetland Transitions To Other Land Uses: Tidal Marshes, Mangrove Forests, And Seagrass Beds, Catherine E. Lovelock, James W. Fourqurean, James T. Morris

Faculty Publications

The sediments of coastal wetlands contain large stores of carbon which are vulnerable to oxidation once disturbed, resulting in high levels of CO2 emissions that may be avoided if coastal ecosystems are conserved or restored. We used a simple model to estimate CO2 emissions from mangrove forests, seagrass beds, and tidal marshes based on known decomposition rates for organic matter in these ecosystems under either oxic or anoxic conditions combined with assumptions of the proportion of sediment carbon being deposited in either oxic or anoxic environments following a disturbance of the habitat. Our model found that over 40 years after …

Mineralizing Filamentous Bacteria From The Prony Bay Hydrothermal Field Give New Insights Into The Functioning Of Serpentinization-Based Subseafloor Ecosystems, Céline Pisapia, Emmanuelle Gérard, Martine Gérard, Léna Lecourt, Susan Q. Lang, Bernard Pelletier, Claude E. Payri, Christophe Monnin, Linda Guentas, Anne Postec, Marianne Quéméneur, Gaël Erauso, Bénédicte Ménez

Faculty Publications

Despite their potential importance as analogs of primitive microbial metabolisms, the knowledge of the structure and functioning of the deep ecosystems associated with serpentinizing environments is hampered by the lack of accessibility to relevant systems. These hyperalkaline environments are depleted in dissolved inorganic carbon (DIC), making the carbon sources and assimilation pathways in the associated ecosystems highly enigmatic. The Prony Bay Hydrothermal Field (PHF) is an active serpentinization site where, similar to Lost City (Mid-Atlantic Ridge), high-pH fluids rich in H2 and CH4 are discharged from carbonate chimneys at the seafloor, but in a shallower lagoonal environment. This study aimed …

Metagenomic Identification Of Active Methanogens And Methanotrophs In Serpentinite Springs Of The Voltri Massif, Italy, William J. Brazelton, Christopher N. Thornton, Alex Hyer, Katrina I. Twing, August A. Longino, Susan Q. Lang, Marvin D. Lilley, Gretchen L. Früh-Green, Matthew O. Schrenk

Faculty Publications

The production of hydrogen and methane by geochemical reactions associated with the serpentinization of ultramafic rocks can potentially support subsurface microbial ecosystems independent of the photosynthetic biosphere. Methanogenic and methanotrophic microorganisms are abundant in marine hydrothermal systems heavily influenced by serpentinization, but evidence for methane-cycling archaea and bacteria in continental serpentinite springs has been limited. This report provides metagenomic and experimental evidence for active methanogenesis and methanotrophy by microbial communities in serpentinite springs of the Voltri Massif, Italy. Methanogens belonging to family Methanobacteriaceae and methanotrophic bacteria belonging to family Methylococcaceae were heavily enriched in three ultrabasic springs (pH 12). Metagenomic …

A Comparison Of Pesticide Monitoring Programs, State Vs. Federal, Justin Marshall

Theses and Dissertations

Exposure to pesticide residues continues to be a threat to both human and environmental health despite increased efforts in the agricultural industry to control end-product levels. Multiple government agencies routinely sample and screen common agricultural commodities (fruits and vegetables) for pesticide residues, albeit to do so they use different commodity sampling methods and satisfy different program objectives. Often, results of such screening programs are used in a supplementary fashion in human and environmental health studies, but rarely are the results studied against one another. Six years of archived data (narrowed down from 14) of two separate pesticide monitoring programs were …

Subsurface Transport In A North Inlet, South Carolina Salt Marsh: A Porewater Salinity Model, Carolyn Ryan

Theses and Dissertations

Subsurface transport in coastal salt marshes influences the nutrient budget of coastal environments, but is not fully understood. To expand our understanding of this transport, a simple numerical model was developed. The model simulated vertical transport of salt through the surficial muds at a North Inlet marsh on the coastal plain of South Carolina. To improve the model, a tracer study was utilized to calculate the average velocity of groundwater flow through the system. The model was compared with porewater salinity measured using tension samplers and passive diffusion samplers. Each method produced different, uncorrelated results. However, accounting for macro-pores in …

Tectonic Studies Of Southeastern North America: The Suwannee Basin, Brunswick Suture Zone, Osceola Arc, And Pangean Transcurrent Fault System, Susannah Katherine Boote

Theses and Dissertations

A series of exotic terranes with complex tectonostratigraphic relationships construct the North American margin and record information critical to understanding the evolution of the Appalachian orogen. The Coastal Plain cover remains a challenge in this region; however, synthesis of seismic reflection, seismic refraction, well, and aeromagnetic data allows for a substantially revised interpretation of the basement rocks and structures that comprise the pre-Mesozoic crust of southeastern North America. These data reveal: (1) a Neoproterozoic subduction zone and paired continental-margin arc are preserved in Gondwanan crust in southeastern North America, (2) the Gondwanan Suwannee Basin of Early to Mid-Paleozoic age is …

Utilizing Structure-From-Motion Photogrammetry And Unmanned Aerial Vehicles To Characterize Variability In Fluvial Deposits From The Salt Wash Member Of The Morrison Formation, East-Central Utah, John Chesley

Theses and Dissertations

Modern fluvial systems are highly variable, often containing the entire spectrum of fluvial styles (e.g., braided to meandering). This variability is difficult to capture in ancient fluvial deposits due to limited 1- and 2-dimesional exposures, which provide only a snapshot of the depositional history at one location. As a result, researchers are forced to interpolate between exposures and develop regional scale models that often underestimate the complexity and variability seen in modern environments. Outcrops of the Upper Jurassic Salt Wash Member of the Morrison Formation in east-central Utah, USA provide a relatively unique opportunity to examine ancient fluvial sandstone bodies …