Digital Commons Network^™

The Effects Of Sediment Acidification And Temperature On The Immune Capacity Of The Atlantic Jackknife (Razor) Clam (Ensis Leei M. Huber, 2015), Brian Preziosi

Electronic Theses and Dissertations

Sediment acidification has been shown to negatively impact clams of economic importance such as the soft-shell clam, Mya arenaria Linnaeus, 1758, and hard clam, Mercenaria mercenaria (Linnaeus, 1758). Effects of sediment acidification on razor clams, including the Atlantic jackknife clam Ensis leei M. Huber, 2015, are unknown. E. leei has been identified as a species with potential for aquaculture operations on the New England coast. E. leei may be resilient to acidification and thus persist in acidified sediments where other clams cannot. To this end, the impact of acidified surface sediment on the internal immune capacity of adult (mean shell …

2d Electrical Resistivity And Hydrological Study Of A Solute Plume’S Migration Pathway Through Sandy Loam Within Nacogdoches County, Texas, Usa, Tyler Tandy, Wesley Brown, Kevin Stafford

Electronic Theses and Dissertations

combined geophysical and hydrological study was conducted in a sandy loam near the campus of Stephen F. Austin State University in Nacogdoches, Texas. The study area contained three preinstalled piezometers which are located in the Sparta Sand of the Eocene Claiborne Group, a regressive tract of the Eocene sea. Electrical DC resistivity surveys were conducted across one fifty-six-meter-long traverse using AGI’s multi-electrode SuperSting R8 WIFI RES/IP/SP system, which allowed for rapid and reliable data collection. The resistivity line was surveyed using the dipole-dipole array configuration, which has been proven to produce high-quality horizontal resolution. Over the duration of fourteen days, …

Manus Descriptions Of An Undescribed Mastodon From The Latest Miocene-Earliest Pliocene Gray Fossil Site, With Comparisons To Other North American Proboscidean Taxa, Brenna Hart-Farrar

Electronic Theses and Dissertations

A detailed morphological description of a proboscidean manus from the Gray Fossil Site (GFS), Gray, Tennessee is provided. Manus elements from an American mastodon (Mammut americanum), a Britt’s shovel-tusker (Amebelodon britti), an undescribed small gomphothere species, and a Columbian mammoth (Mammuthus columbi) are used for comparisons. Linear measurements indicate proportional differences between the GFS mastodon and other proboscidean taxa ranging from the Hemphillian to Rancholabrean land mammal ages. Possible pathologies are also described. The purpose of this study is to determine how the GFS mastodon differs in manus morphology and locomotion from different proboscidean …

The Potential Of Radium-224 As A Tracer Of Timescales Of Gulf Of Mexico Crude Oil Exposure To The Marine Environment, Matthew T. Kurpiel

Electronic Theses and Dissertations

Petroleum pollution in the marine environment can be deleterious to coastal and marine ecosystems and can have sustained effects for years. While oil slicks on the surface of the ocean are tracked with relative ease using satellite-based technology, deep sea, neutrally-buoyant hydrocarbon plumes remain exceedingly difficult to track. We provide evidence for the utility of Ra-224 as a potential hydrocarbon tracer to determine the marine exposure time of crude oil. We employed time course incubations to constrain a time dependent Ra-224 release signature and tested a variety of timescales, temporal resolutions, oil sources, seawater, and experimental treatments to determine potential …

Mechanisms Of Ice Core Stable Isotope Variability In The Upper Kaskawulsh-Donjek Region, St. Elias Mountains, Yukon, Canada, Erin A. Mcconnell

Electronic Theses and Dissertations

I use instrumental and ice core records to examine drivers of observed isotope variability in the Upper Kaskawulsh-Donjek (UKD) region of the St. Elias Mountains, Yukon, Canada over the time frame of instrument-proxy overlap (mid-1900s to present). One of the drivers of post-depositional isotope signal alteration is the vertical percolation of meltwater from the glacier surface through shallow layers of snow, which causes a reduction in the amplitude of the isotope signal recorded in ice cores. I examine isotope signal preservation in two sites in the St. Elias Mountains: Eclipse Icefield and Icefield Divide. These sites are relatively close (~30 …

Fractures, Fluids, And Metamorphism: Shear Zone Initiation In The Marcy Anorthosite Massif, Adirondacks, New York, Usa, James Hodge

Electronic Theses and Dissertations

Localized shear zones are important rheological features that influence deformation behavior throughout the Earth’s middle-to-lower crust. Therefore, the processes through which shear zones initiate and localize remains an important geologic question. The study of strain localization and shear zone initiation is made difficult due to continued deformation overprinting the microstructures which lead to initiation and obfuscating the context in which localization occurred. The Marcy anorthosite in the Adirondack Highlands, New York, is a nominally granulite-facies, plagioclase-rich massif cut by centimeter-to-meter scale shear zones which provides a natural example of shear zone localization within the middle-to-lower crust. My work focuses on …

2-D And 3-D Temporal Modeling Of Solute Migration Through Low Permeable Media Using Electrical Resistivity, Nacogdoches County, Texas, Kaleb Henry, Kevin W. Stafford, Wesley Brown, Melinda Faulkner, Matthew Mcbroom

Electronic Theses and Dissertations

The Reklaw Formation is the upper bounding unit for the Carrizo-Wilcox Aquifer throughout the Gulf Coastal Plain of East Texas and consists of low permeability, glauconite-rich strata that isolate semi-confined portions of the aquifer system from potential contaminants. Electrical resistivity methods were employed within a forested watershed in Nacogdoches County, Texas to characterize solute transport. 2-D and 3-D temporal resistivity data collected with an AGI SuperSting (R8/IP) were processed with AGI Earthimager 2D/3D software for inversion modeling. Data were collected over 135 days within a 14 X 26 meter (46 X 85 feet) gridded survey at 15-day intervals after initiation …

The Role Of A Permeable Sand Column In Modifying Tidal Creek Geochemistry And Land-Derived Inputs To The Coastal Ocean, Nicholas Anthony Legut

Electronic Theses and Dissertations

The impairment of regional water quality in Long Bay is an episodic occurrence that has been documented for over a decade. According to one explanation, the occurrence of these events is hypothesized to be the combination of local, terrestrially derived inputs and water-column stratification in the nearshore zone. A portion of these inputs may discharge as surface run-off through estuaries ending in sandy transitional environments termed "swashes". An investigation into the fate of land-derived materials through swashes utilize a linear conservative mixing model to describe the non-conservative behavior of materials in the overlying water and pore-water. This model relies on …

Reconstructing A Centennial-Scale Extreme Paleoflood History Of The Pee Dee River Using Oxbow Lake Sediments, Nicholas William Conway

Electronic Theses and Dissertations

Extreme river floods are the key force shaping floodplain landscape and a major process delivering sediment, pollutants, and nutrients to coasts. These devastating natural hazards pose concerns about potential change of extreme flood occurrence in the face of climate change. However, accurately assessing the impact of anthropogenic climate change and natural climate modes on the intensity and frequency of extreme flooding relies on multi-century discharge records. Unfortunately, instrumental records are relatively short (often <100 years) and overlap with times of dam and reservoir construction. Oxbow lakes, ubiquitous in the floodplains of alluvial rivers, may preserve an archive of extreme flood at centennial timescales as they capture coarser channel sediments transported by intensified river flows. This study has identified signals of extreme floods in oxbow lake sediments and established a timeline of past flooding events to evaluate change(s) in flood hazard near the Pee Dee River (PDR), South Carolina. Laser diffraction grain-size analysis and X-ray computed tomography (CT) scanning were performed on a ~2-m long piston core (SBL2) to identify event layers of extreme floods. CT images reveal high-density laminations and corresponding coarser shifts of grain size are interpreted as flood layers. A robust age-depth model was established for SBL2 using multiple independent age controls (C14, optically stimulated luminescence, Pb210/C137, and historical event tie-points). End-member modelling analysis was performed to identify a coarse component of the grain-size data used as a proxy of extreme flood. A linear relationship between end-member modelling results and measured discharge was established for the last 80 years and applied to the older part of the core yielding peak discharge estimates back to ca. AD 1840. This analysis identifies abrupt shifts in grain size resulting from dam construction, droughts, and local geomorphic changes to the river system. A multidecadal trend in the frequency of extreme floods is present in the PDR system, controlled by Pacific Decadal Oscillation. The most extreme peak annual discharges of the PDR occurred between AD 1870-1900 from the combined interaction of increased tropical cyclone activity with intensified land use for agricultural purposes. Peak annual discharges of the PDR seem to have decreased through time since flood control damming was completed in AD 1962.

A Log And Core Analysis Of The Marmaton Group, Granite Wash Fan Delta In The Anadarko Basin, Washita County, Oklahoma, Cole A. Hatchel

Electronic Theses and Dissertations

The Pennsylvanian Marmaton Group Granite Wash located in the southern Anadarko Basin is a fan delta system that consists of stacked arkosic sandstones, conglomerates, and shale, and within Washita County, Oklahoma, are known to be a prolific hydrocarbon producer. The Marmaton Group in Washita County, though, has a variable and largely unestablished stratigraphic framework and sudden changes in lithology throughout the region, both horizontally and laterally. This combined with a lack of core or outcrop data has created confusion in the subsurface, and the Marmaton Group has remained largely unstudied in southern Washita County, OK.

This study examined two sets …

Improved Estimates Of Tributary Nitrogen Load To Casco Bay, Maine, Whitley J. Gray

Electronic Theses and Dissertations

Over the past two decades, total nitrogen (TN) concentrations have increased in Casco Bay (CBEP 2015). The sources of the increased nitrogen are poorly understood but occur with simultaneous population growth and land use changes. The total riverine nitrogen load to Casco Bay was previously estimated by Liebman and Milstead (2012) using the United States Geologic Survey’s (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model. The SPARROW model uses watershed characteristics, regional monitoring data and nitrogen source data to estimate nitrogen loading but was not validated using measurements of nitrogen in the Casco Bay watershed. This study attempts to …

Comparing Structure From Motion Photogrammetry And Computer Vision For Low-Cost 3d Cave Mapping: Tipton-Haynes Cave, Tennessee, Clinton Elmore

Electronic Theses and Dissertations

Natural caves represent one of the most difficult environments to map with modern 3D technologies. In this study I tested two relatively new methods for 3D mapping in Tipton-Haynes Cave near Johnson City, Tennessee: Structure from Motion Photogrammetry and Computer Vision using Tango, an RGB-D (Red Green Blue and Depth) technology. Many different aspects of these two methods were analyzed with respect to the needs of average cave explorers. Major considerations were cost, time, accuracy, durability, simplicity, lighting setup, and drift. The 3D maps were compared to a conventional cave map drafted with measurements from a modern digital survey instrument …

Modeling Extreme Heat Events Using Global Reanalysis Data: An Assessment Of Current Climate Data And The Need For Improved Weather Station Data In Tennessee, John Reasons

Electronic Theses and Dissertations

Wet Bulb Globe Temperature (WBGT) is used to assess categorical heat stress risk factors for individuals working in outdoor environments and to provide guidelines for work/rest ratios and water intake. The variables required to compute WBGT are used by meteorologists for many purposes and are available through the Copernicus Program which was implemented by European Centre for Medium-Range Weather Forecasts (ECMWF) to provide users access to ECMWF Re-Analysis (ERA) historical database. WBGT values for Tennessee during National Weather Service (NWS) issued excessive heat warnings were calculated to determine the need for additional advisories based on WBGT guidelines. Monthly average WBGT …

Debris-Slide Susceptibility Modelling Using Gis Technology In The Great Smoky Mountains National Park, Raja Das

Electronic Theses and Dissertations

Debris-slides are one of the most frequently occurring geological hazards in metasedimentary rocks of the Anakeesta ridge in Great Smoky Mountains National Park (GRSM), which often depends on the influence of multiple causing factors or geo-factors such as geological structures, slope, topographic elevation, land use, soil type etc. or a combination of these factors. The main objective of the study was to understand the control of geo-factors in initiating debris-slides using different knowledge and data-driven methods in GIS platform. The study was performed in three steps: (1) Evaluation of geometrical relationship between geological discontinuity and topographic orientation in initiation of …

Evaluating Fluid Fluxes From Deep-Sea Seepage Habitats, Leigha E. Peterson

Electronic Theses and Dissertations

The permanently dark deep-sea, located at oceanic water depths greater than 200 m, represents the largest potential habitat space on Earth. The physicochemical conditions of the planet’s largest biome are tightly coupled to the exchange of matter and energy from terrestrial and sea-floor end-members. In fact, global ocean and climate systems are significantly impacted by deep-sea processes. Seafloor vents and seeps appear to act as geologic exchange conduits, returning recycled materials to the hydrosphere to sustain another generation of life. Despite submarine seepage having control on global elemental cycling, it is estimated that less than 1% of the deep-sea has …

A Multi-Proxy Paleoecological Reconstruction Of Holocene Climate, Vegetation, Fire And Human Activity In Jamaica, West Indies, Mario A. Williams

Electronic Theses and Dissertations

Jamaica is located in the Caribbean biodiversity hotspot and has a rich flora and fauna, most notably characterized by exceptional levels of plant endemism. These natural resources are imperiled by climate change and increasing anthropogenic pressures, therefore highlighting the importance of implementing effective conservation programs to mitigate ecosystem degradation. Paleoecological studies that investigate the diversity and distributions of organisms and their habitats over millennial timescales provide critical long-term spatial and temporal context for the assessment of contemporary environmental problems. Lake sediments are a highly useful archive for the study of prehistoric climate and ecological changes, as biological, chemical and geophysical …

Facies And Diagenesis Analyses Of The Fort Terrett Formation Of The Lower Cretaceous Edwards Group, Near Junction, Texas, Richard Alden Urwin Jr.

Electronic Theses and Dissertations

The Fort Terrett Formation was deposited on the western edge of the Comanche Shelf in central Texas. The predominate lithology of the Fort Terrett Formation is limestone which caps the hills that surround Junction, Texas. Deposition of the Fort Terrett Formation occurred within shallow, quiet waters during the Lower Cretaceous. Rose (1974) developed a general stratigraphic correlation and lithostratigraphic framework for the Cretaceous Shelf and established a regional correlation. Four stratigraphic divisions have been recognized in the Fort Terrett Formation. These are: a basal nodular unit, a burrowed unit, a dolomitic unit, and the Kirschberg evaporites. Wilkerson (2018) provided the …

Past, Present, And Future Arctic Climate And National/Community Risk Assessment, Jeff Auger

Electronic Theses and Dissertations

The Arctic is warming at a rate nearly double that of the global average. The enhanced rate of warming impacts weather and climate across the Northern Hemisphere. As the meridional (south to north) thermal gradient weakens, the middle-latitude westerlies are expected to slow and become “wavier” increasing heat and moisture advection to higher latitudes. A quasi-stationary ridge-trough system of the jet stream increases chances for droughts, floods, heatwaves, and cold spells. These impacts have already been observed as North American forest fires and early or extended Great Lake ice out. It is more important than ever to understand how the …

Determining The Influence Of Lateral Margin Mechanical Properties On Glacial Flow, Kate Hruby

Electronic Theses and Dissertations

The lateral margins of glaciers and ice streams play a significant role in glacial flow. Depending on their properties, like temperature and ice crystal orientation, they can cause a resistance to flow or enhance it. In combination with our current changing climate, flow patterns can dictate the mass balance of an ice body. It is therefore more important than ever to understand the impact that variations at the margins can have on flow. However, the lateral margins of glaciers and ice streams are an often-neglected part of ice dynamics; they are harder to sample than the center of a glacier’s …

Ecometric Estimation Of Present And Past Climate Of North America Using Crown Heights Of Rodents And Lagomorphs: With Application To The Middle Miocene Climatic Optimum, Julia Schap

Electronic Theses and Dissertations

Continental scale studies on ungulate crown heights in relation to climate and habitat changes have revealed a correlation between increasing hypsodonty and a shift to more arid environments. Small mammals have been shown to adapt to changing habitats millions of years earlier than larger mammals. In this study I examined fossil localities throughout the last 37 Ma across North America. Diversity of rodents and lagomorphs were analyzed through this time period, with examination of community structure characterized by relative percentages of taxa with different crown heights. Overall, a decrease in precipitation and temperature was found across North America from 37 …

A Systematic Assessment Of Socio-Economic Impacts Of Prolonged Episodic Volcano Crises, Justin Peers

Electronic Theses and Dissertations

Uncertainty surrounding volcanic activity can lead to socio-economic crises with or without an eruption as demonstrated by the post-1978 response to unrest of Long Valley Caldera (LVC), CA. Extensive research in physical sciences provides a foundation on which to assess direct impacts of hazards, but fewer resources have been dedicated towards understanding human responses to volcanic risk. To evaluate natural hazard risk issues at LVC, a multi-hazard, mail-based, household survey was conducted to compare perceptions of volcanic, seismic, and wildfire hazards. Impacts of volcanic activity on housing prices and businesses were examined at the county-level for three volcanoes with a …

Paleoecology And Land-Use Of Quaternary Megafauna From Saltville, Virginia, Emily Simpson

Electronic Theses and Dissertations

Land-use, feeding habits, and response to seasonality by Quaternary megaherbivores in Saltville, Virginia, is poorly understood. Stable isotope analyses of serially sampled Bootherium and Equus enamel from Saltville were used to explore seasonally calibrated (δ¹⁸O) patterns in megaherbivore diet (δ¹³C) and land-use (⁸⁷Sr/⁸⁶Sr). Overall, this dataset suggests an open forest with relatively constant temperatures year round that were similar to modern conditions. Neither Bootherium or Equus individuals spent a significant amount of time at higher elevations in the nearby Blue Ridge geologic province. These analyses provide a unique perspective on long-term response …

Root Biomass And Other Soil Properties Affecting The Co2 Flush From Laboratory Dried And Rewetted Soils, Audrey E. Laffely

Electronic Theses and Dissertations

Soil that has been dried and rewetted has been observed to release a ‘burst’ or ‘flush’ of carbon dioxide (CO 2 ) upon rewetting. This CO 2 flush has been proposed as an indicator of soil health. This may be a valuable indicator of soil health, however the CO 2 flush has yet to be fully evaluated. Roots and root exudates influence the soil in a variety of ways that may impact the CO 2 flush, such as increasing aggregation, organic carbon (C), and microbial biomass. We conducted both field and greenhouse experiments to elucidate the relationship of root biomass …

Brassica Carinata Growth And Yield Response To Nitrogen And Sulfur Fertilizers And Impacts On Selected Soil Parameters And Ghg Fluxes, Dwarika Bhattarai

Electronic Theses and Dissertations

Carinata (Brassica carinata A. Braun), a non-food oilseed crop and an alternative bio-jet fuel feedstock, has received attention for its potential as a low-input option for production in the semi-arid regions of the Northern Great Plains of USA. The crop has a lower N fertilizer requirement as compared to the other oilseeds, suggesting less negative impact on soils and GHGs emissions. Carinata is a new crop to South Dakota (SD), thus, the best management practices have yet to be developed. In addition, no sufficient research to address the impact of growing carinata on soils and GHG emissions has been …

Use Of Seismic Refraction In Determining Rock Mass Anisotropy, Mohammad Najmush Sakib Oyan

Electronic Theses and Dissertations

Seismic refraction is a popular method used by geological/geotechnical engineers to understand subsurface conditions. This method along with information collected from borings produce a realistic image of the ground beneath us. The goal of this study is to define and test a set of procedures to use seismic refraction alone to create high quality images of subsurface conditions. The focus is on areas with several meters of soil overlain by bedrock. The application of these procedures will minimize construction costs by eliminating the need for multiple boreholes. The results show that two important criteria must be met for successful application …

Estimating Soil Organic Carbon In Cultivated Soils Using Soil Test Data, Remote Sensing Imagery From Satellites (Landsat 8 And Plantscope), And Web Soil Survey Data, Muhammed Halil Koparan

Electronic Theses and Dissertations

Soil organic carbon (SOC) is an important soil parameter of cultivated soils that needs to be monitored and mapped regularly to enhance soil health and productivity. SOC levels in cultivated areas is difficult to monitor for farmers and is costly to analyze using traditional methods. The objective of this study was to estimate surface SOC distribution in selected soils of Major Land Resource Areas (MLRA) 102A (Rolling Till Plain, Brookings County, SD) and 103 (Central Iowa and Minnesota Till Prairies, Lac qui Parle County, MN) using soil sample data, Web Soil Survey (WSS) data, and satellite imagery (Landsat 8 and …

Generalized Radial Transport Model For Interpreting Convergent Flow Tracer Tests In Fractured Rock, Md Lal Mamud

Electronic Theses and Dissertations

The double-porosity Generalized Radial Transport (GRT) model is an extension of the generalized radial flow approach developed for hydraulic test interpretation. In both approaches, a flow dimension characterizes the change in flow area versus radial distance from the borehole. The GRT model collapses to a 1D, radial, and spherical advection dispersion equation (ADE) for integer flow dimensions of 1, 2, and 3, respectively. And, the model also transforms to sub-linear, sub-radial, sub-spherical and eventually transform to super-spherical transport model for non-integer flow dimension, n of 0 < n < 1, 1 < n < 2, 2 < n < 3 and n >3 respectively. Non-integer flow dimensions, especially sub-radial, are commonly reported from pumping tests in …

Long-Term Impacts Of Manure And Inorganic Fertilization On Soil Physical, Chemical And Biological Properties, Asmita Gautam

Electronic Theses and Dissertations

The intensive use of mineral fertilizers to achieve high crop yield has led to soil degradation and poor soil health. Thus, manure application as an alternative to mineral fertilizers can be an effective fertilization strategy to improve soil health and biodiversity. This study aims to assess the impacts of long-term manure and mineral fertilizers on soil physical, chemical and biological properties. The experimental site was initiated in 2003 near Beresford, South Dakota on Egan soil under a randomized complete block design with four replications and six treatments. The study treatments included: three manure rates [low manure (LM), manure application based …

The Impacts Of Land Use And Land Cover Change On Water Quality In The Big Sioux River: 2007-2016, Dinesh Shrestha

Electronic Theses and Dissertations

Between 2006 and 2012, conversion of 485,000 acres of grassland to cropland in eastern South Dakota was reported. In 2012, the Big Sioux River (BSR) running through most of eastern South Dakota was listed among the dirtiest rivers in the nation. This rating convinced state authorities to study trends of land cover changes in the BSR watershed and its association with BSR water quality with respect to increases in nitrate levels. This research i) quantifies spatial and temporal changes in the land cover types within the BSR watershed, and ii) identifies any correlation between these changes and changes in BSR …

Isolation And Identification Of Potential Bioinoculants Based On Phosphate Solubilizing And Plant Growth Promoting Benefits, Rachel Raths

Electronic Theses and Dissertations

Conservative models have shown that as populations rise, food production needs to double by 2050. Population increase and the green revolution have caused fertilizer inputs to increase since the 1960’s, increasing environmental issues and production costs. These intensive practices have led to degraded arable land and there has been an increase in urbanization meaning we need to make best use of the farming land that is available and ensure it is sustainable for future food production. Due to this, there has been a higher demand for research on more environmentally and economically friendly approaches to food production. Plant growth promoting …