Physical Sciences and Mathematics Commons^™

Impact Of Soil Water Content On Bermudagrass Athletic Field Performance, Kyley Hampton Dickson

Doctoral Dissertations

Soil water content (SWC) influences the consistency and performance of athletic fields. Two studies were conducted at the University of Tennessee Center for Athletic Field Safety (Knoxville, TN) to determine SWC impact on the performance of hybrid bermudagrass [Cynodon dactylon (L.) Pers. x C. transvaalensis, Burtt-Davy, ‘Tifway’] on silt loam (cohesive) and sand root zone conforming to United States Golf Association (USGA) specifications (noncohesive) root zones. Soil water content treatments for the cohesive soil averaged 0.10 m³/m³ (+/- 0.035), 0.17 m³/m³ (+/- 0.035), 0.26 m³/m³ (+/- 0.035), and 0.35 …

Biogeochemical Characteristics Of Organic Matter In A Karst Groundwater System, Teresa Lynn Brown

Doctoral Dissertations

Development of regional groundwater carbon budgets hinges on the ability to quantify and monitor biogeochemical processes controlled by microbial recycling of natural dissolved organic matter (DOM) in carbon-limited (oligotrophic) areas. DOM is the major reservoir of organic carbon in aquatic ecosystems. However, isolation and characterization of DOM in oligotrophic freshwater systems has been limited by operational protocols and instrumentation. The goals of this research were to investigate the seasonal dynamics of microbially-driven organic matter degradation in a karst groundwater system influenced by surface water, and to identify analytical tools and biomarkers to measure long-term hydro-ecological trends in the Appalachian region. …

Development Of Nuclear Underground Engineered Test Surrogates For Technical Nuclear Forensics Exploitation, Robert Boone Gilbreath

Masters Theses

A method for formulation and production of Nuclear UnderGround Engineered Test Surrogates (NUGETS) based on notional improvised nuclear device (IND) detonations in an underground environment analogous to the Nevada National Security Site (NNSS) is presented. Extensive statistical analyses of precursory geochemical and geophysical characteristics are combined with an augmented surrogate debris cooling technique and predictive IND contributions from the ORIGEN Fallout Analysis Tool. Precursory and resultant elemental compositions, cooling curve calculations, and visual comparison of NUGETS to genuine underground debris are reported. Application of NUGETS methodology to future studies in urban, underground post-detonation technical nuclear forensic (TNF) analysis is suggested.

Influence Of Environmental Conditions And Inundation History On Bacterial Diversity Of Salt Marsh Soils In Southern Louisiana, Brandon M. Bagley

Masters Theses

Diversity patterns and controls on bacterial community composition were investigated from coastal salt marsh soils in southern Louisiana (USA) from 2012 – 2014. These salt marshes are part of an extensive coastal landscape that is experiencing land loss due to subsidence, sea-level rise, and anthropogenic activities, including from the impacts of the Deepwater Horizon oil spill in 2010. Prior to the oil spill, microbiology research focused predominately on biogeochemical roles and not on taxonomic representation in the soils or on understanding the significance of taxonomic diversity at the microbial level to marsh food webs or ecosystem dynamics. The purpose of …

Influence Of Algae On Soil Saturated Hydraulic Conductivity: An In Situ Treatment Option For Reducing Infiltration Beneath Unlined Algae Cultivation Ponds, Molly Brianne Pattullo

Masters Theses

Commercial production of algal biofuels is currently limited by high capital costs, including the cost of installation and maintenance of plastic pond liners, which mitigate seepage of cultivation fluids and control the release of salts and nutrients into the subsurface beneath outdoor algae cultivation ponds. However, studies of animal waste settling lagoons show that underlying soils ranging from sands to clay loams can exhibit reduced hydraulic conductivity within days to weeks after construction, reducing the need for plastic liners. The mechanisms of the hydraulic conductivity reductions, or “soil sealing”, are physical rearrangement of soil particles, buildup of fines, and the …

Determining Sources Of Nitrate In The Semi-Arid Rio Grande Using Nitrogen And Oxygen Isotopes, Diego Alberto Sanchez Hernandez

Masters Theses

The Rio Grande, a semi-arid river in the American Southwest, is a major source of surface water for agriculture and drinking supplies in New Mexico and Texas. In addition to increasing salinity, considerable increases of NO₃^- [nitrate] have been observed in the semi-arid portion of the Rio Grande. It is possible that elevated water salinity inhibits denitrification on irrigated fields and, thus, fails to mediate excess nutrient load from anthropogenic activities. Therefore, two major goals of this project were to 1) characterize and quantify major NO₃^- sources, and 2) assess whether elevated water salinity affects microbial …

Effects Of Switchgrass Related Land-Use Changes On Aquatic Macroinvertebrates, Latha Malar Baskaran

Doctoral Dissertations

This research examines if switchgrass-based land-management practices have the potential to influence aquatic macroinvertebrates through changes in stream flow and water quality. The number of taxa in Ephemeroptera, Plecoptera, and Trichoptera orders (EPT taxa richness/EPT-TR) is analyzed as an aquatic macroinvertebrate bioindicator in the context of regional environmental effects, and changes in stream flow and water quality. This dissertation is structured as three manuscripts that link together to address the overall research question.

The first manuscript focuses on identifying regional environmental variables that influence EPT-TR across ecoregions in Tennessee. The influences of temperature, precipitation, geology, soil, stream flow and velocity …

The Homology And Phylogeny Of The Diploporita (Blastozoa: Echinodermata), Sarah Lynne Sheffield

Doctoral Dissertations

Evolutionary relationships of extinct echinoderms are poorly understood, especially within stem-bearing blastozoans, a large group of echinoderms with unique respiratory structures and feeding brachioles. They were highly experimental in their body plans and very unlike echinoderms today (e.g., sea urchins). Many of the blastozoan subgroups recognized in recent classifications do not represent clades (natural associations of organisms derived from a single ancestor); they are either grades of organization or groups united by superficially similar features. Consequently, these ‘traditional’ groupings cannot be used to analyze evolutionary questions, such as biogeography or rates of evolution. This problem is highlighted within the diploporitan …