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 …

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 …

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 …

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. …