Environmental Sciences Ph.D. (EVS) Current Students

Meet Our Current PhD Students 

 

Meet our current students and read about their research below.

 

Namal Abeysooriya - Chemistry

Namal is originally from Sri Lanka and an Erasmus Mundus Scholar Alumni. Before joining TTU, he studied and conducted research in France, Portugal, Spain, the Netherlands, and Sri Lanka in the field of environmental science. His dissertation is titled "Fundamental Photodetachment Studies of Isoprene and Other Atmospherically Relevant Linear and Cyclic Systems." His research primarily focuses on atmospheric chemistry, specifically predicting the vibrational spectra and thermochemistry of isoprene and polycyclic aromatic hydrocarbons using infrared and photoelectron spectroscopic techniques.

Daniel Adams - Integrated Research

Daniel’s research is titled: “Enhancing Building-Stock Data Attribution with Machine Learning and the Implications for Quantifying Uncertainty in Estimated Populations at Risk of Water Insecurity.” Daniel’s research focuses on advancing geospatial science and knowledge around building-stock attribution and its implications for quantifying uncertainty in deterministic human population models. Human population data are paramount for effective emergency response and urban planning strategies, particularly in coastal areas at risk of flooding and rising sea levels. The models used to create these vital population data, make use of assumptions for model inputs that at times fall short of accurately characterizing the human built environment. This can result in human population estimates that do not accurately capture a realistic number of people present in any given geography and can have adverse effects when used for emergency response or climate adaptation and mitigation strategies. Daniel seeks to quantify the uncertainty present in existing population data by utilizing data augmentation and machine learning methodologies to evaluate the veracity of the assumptions used in the deterministic modeling process. He aims to leverage the quantified uncertainty as an informative input for structured decision making in sea level rise impact assessments, thus improving planning and mitigation strategies for communities vulnerable to climate change impacts.

Peter Blum- Biology

Peter's research is titled: "Transfer of PCBs from Emergent Insects to Terrestrial Consumers in Historically Contaminated Streams and Reservoir." His dissertation focuses on how stream insects that develop in polychlorinated biphenyls (PCBs) contaminated sediments can transfer PCBs to terrestrial consumers when they emerge as winged adults. Gray bats (Myotis grisescens) utilize emergent aquatic insects in their diet, which provides a route for PCB exposure and a potential concern for their conservation. Because PCBs are resistant to decomposition, historical contamination of PCBs at Wood’s Reservoir and several streams near Arnold Air Force Base may be sources of PCB exposure to local gray bat colonies. His research investigates how much insect biomass is emerging from these streams and reservoirs sites as a potential food source for bats, the PCB flux from these emergent aquatic insects, and how nutrient stoichiometry (the ratios of major nutrients in insects) affects PCB biomagnification.

Martine Patiance Bowombe-Toko- Agriculture

Martine is originally from Mbanga (Littoral region, Cameroon) and her research study focuses on preventing or controlling periodical cicada oviposition damage associated with nursery tree crops. Her dissertation is titled, "Determining control strategies for periodical cicadas in commercial ornamental nursery plants in Tennessee."  To accomplish this goal, two major priorities will be addressed: 1) evaluation of new or current insecticide treatments to manage periodical cicada adults using cage studies in shadehouse settings and 2) assessment of nursery tree damage by periodical cicada adults (Brood X, 2021) in cooperating East Tennessee field nurseries. However, with limited nurseries located so far, they will include the insurance assessment reports from the 2011 emergence, to return in 2024, and from the 2008 emergence to return in 2025.

Bryant Davis- Integrated Research

Bryant's project is titled "Geochemical Fingerprinting of Natural Waters in Middle Tennessee." Geochemical fingerprinting is an analysis of the chemical species, present within natural waters, to determine both the source and alteration of these systems. These chemical fingerprints are defined as specific patterns of analytes unique to each body of water. This research examines the presence of metals in surface waters that are located on two distinct physiographic regions of Tennessee: the Highland Rim and the Cumberland Plateau.  Water bodies from these regions were chosen due to differences in local geology and land use patterns that each respective system are subjected to. Grab samples were obtained from various locations in order to obtain an identity of each respective system. Linear regression was then utilized to determine ratios of analytes so that a comparative analysis could then be performed. The obtained correlation coefficients should indicate how local geology and land use patterns affect the chemical identity of natural waters within Middle Tennessee.

Ronnie Dunn - Agriculture

Dissertation Title: “Optimizing and Modeling Nutrient Use in a Drip Hydroponic System for Tomato Production.” Ronnie’s research deals with the optimization of production methods for tomatoes in trough-based, drip hydroponic systems and with a biological model for transpiration that can be used in an app-based decision model to inform nutrient replenishment in closed and semi-closed hydroponic systems. Ultimately, this research could be helpful in the move toward tomato production in closed hydroponic systems and away from open systems that discharge used nutrient solution into the environment, producing negative environmental impacts for surface water and groundwater. Additionally, a more optimal use of nutrient solution by producers could increase producer profits.

Miranda Gaupp - Biology

Miranda received her B.S. from Millsaps College and her M.S. from Georgia Southern University. For her dissertation, she is creating genomic resources for the streamside salamander (Ambystoma barbouri). Specifically, she is assembling and annotating a reference genome and the species' transcriptome. Additionally, Miranda is performing comparative gene expression analysis in order to investigate population-level differences in response to temperature.

Brooke Grubb- Biology

Dissertation title: "An interdisciplinary approach to understanding ecology and genetics of a narrow endemic crayfish species, Faxonius wrighti." Brooke is studying the taxonomic validity, habitat needs, conservation genetics, and movement of Faxonius wrighti (Hardin Crayfish).  Her work will involve aspects of landscape ecology and genomics to understand how the environment influences crayfish movement, genetic structure, and generate predictive models under different climate change scenarios to highlight populations at increased risk of extirpation. Her research will aid in the generation of a species status assessment (SSA) used to make federal listing and management decisions.

Cory Highway - Biology

Dissertation title: "Optimizing wintering waterfowl distribution and hunter opportunities through strategic wetland design." Cory's research examines the impact of anthropogenic disturbance and predation risk on the habitat selection, activity patterns, and distribution of wintering waterfowl in western Tennessee. Specifically, Cory is exploring the strategic placement of rest areas devoid of predation risk to create a more ubiquitous distribution of wintering waterfowl across available habitats. This research also aims to increase harvest opportunities for waterfowl hunters through the reduction of recursive activity patterns in wintering waterfowl, thereby improving stakeholder satisfaction. 

Oluwasola Ifedayo - Chemistry

Oluwasola was born and raised in Lagos, Nigeria. He received his undergraduate degree in Nigeria and had 9 years relevant working experience. He received his masters in Chemistry at Tennessee Tech. Oluwasola is now a Ph.D. Environmental Science Ph.D. Chemistry Concentration student and a member of Dr. Tammy Boles’s lab. His research will be focusing on wastewater analysis to detect and quantify opioid contaminants.

Catherine "Kitty" Phillips - Integrated Research

The title of Kitty's dissertation is "Ethnobotany Among Cherokee and Chocktaw Women: Medical and Spiritual Uses." The basic premise of her research is to explore the plants and methods used by the Cherokee and Choctaw women to cure ills, to prevent illness, to heal wounds, and for overall health.  She will explore which methods worked and why. In addition, she is researching the spiritual or ritualistic uses of plants in their culture.  She also want to determine the overlap between the uses.

Richard Pirkle- Biology

Canada geese in the Upper Cumberland region of Tennessee have been intensively banded over the past two decades. Richard's research involves the analysis of this long-term dataset for patterns that explain Canada goose dispersal, reproduction, and molt site fidelity. In particular, he is interested in how stress may impact nesting physiology and influence social structure amongst unrelated Canada geese. He is also interested in the impact of increased hunting mortality due to banding. 

Phillip Roberson- Geology

Phillip's research focuses on understanding ancient reef-like structures known as Waulsortian mounds. He will be examining the paleoecology, stratigraphy, and geochemistry of these mounds to better understand how and why they formed. 

Sahar Salimi - Integrated Research

Sahar is a bioinformatician in the Rahnama Lab. Her primary research focus lies in studying the genome's evolution and structure of Fusarium species. She conducts in-depth analyses of the genomes of these organisms to gain insights into their genome rearrangement and how it has evolved. Sahar's work in this field is geared towards advancing our understanding of the genetic mechanisms underlying Fusarium species' evolution and pathogenicity.

David Sutton - Integrated Research

David's goal is to study efficient and optimal methodology to transport solid wastes and recyclables from county to destination in Tennessee. The proposed methods used in this study may include geospatial analysis, python data analysis, machine learning model building, and prediction based on various scenarios. Factors such as, not limited to, climate change, population migration, socioeconomic index, groundwater quality in landfills, landfill capacity and life span, and recycling technology, will be used in the modeling process to optimize best management plans for future use.

Christopher Waters- Biology

Chris's research is titled, "Metabarcoding environmental DNA to examine pollinator communities across the range of Physaria globosa (Brassicaceae).” and is part of the recovery and conservation efforts for a federally endangered mustard species called Short’s bladderpod (Physaria globosa(Desv.) O'Kane and Al-Shehbaz). The primary goal of Chirs's research is to investigate and monitor pollinator communities across the range of Short’s bladderpod via metabarcoding environmental DNA (eDNA) on flowers. As insects visit flowers they can leave behind small fragments of DNA in saliva or shed hairs that can be extracted from the flowers and identified to species or taxonomic group. This method allows us to identify and monitor the pollinator community composition across the range of Short’s bladderpod more efficiently compared to traditional sampling techniques.