Past Projects

REU Student: Mr Gabriel Yerdon
Project Mentor: Dr. JD Willson

The loss of prairie habitat in the United States, including Northwest Arkansas which has also lost most of its historic tall grass prairie, has caused population declines in many prairie specialist species. Simultaneously, the Ornate Box Turtle (Terrapene Ornata), which is a prairie specialist species, has experienced population declines in the state and it is currently listed as a Species of Greatest Conservation Need in Arkansas. Three-toed Box Turtles, primarily a forest species, have much more stable populations in Arkansas, and at times utilize the same remnant prairie as T. ornata. Limited information exists on the differences in thermal biology between these species and how those differences may influence their ability to utilize different habitat types. We approached these questions in a three part study. We completed evaporative water loss trials on turtles of both species. Afterwards, we returned these wild caught turtles to their remnant prairie capture sites with iButton data loggers and radio trackers attached to their carapaces. In addition, we placed turtle operative temperature models in degraded prairie, remnant prairie, and forest macrohabitats, and refugia, open and vegetated microhabitats. We found that T. ornatahad significantly lower rates of water loss, and tended to experience higher average and maximum carapace temperatures, and lower minimum carapace temperatures. T. ornatatended to use more open habitat while T. carolinawere more often found in forested habitat and were more likely to use refugia. Operative temperature models recorded higher average temperatures in degraded prairie than forested or remnant prairie habitat, while forest habitat maintained stable, cool temperatures, and remnant prairie had a wider range of cool refugia microhabitats and hot open microhabitats. Our results demonstrate key differences in box turtle thermal biology, and highlight important thermal characteristics of different habitat types that should be considered in T. ornata conservation planning.

 

REU Student: Ms Karina Arellano 
Project Mentor: Dr. Ben Runkle

The purpose of this study was to compare unshaded and shaded regions of an agroforestry research site and quantify soil respiration in each region. We expected to see the unshaded regions to respire more than the shaded regions because of the higher temperatures from the lack of shade and the higher amounts of moisture due to less root competition.

REU Student: Mr. Isaac Bertels
Project Mentor: Dr. Kent Kovacs

Depleted groundwater levels in the Arkansas Delta suggest the need for alternative sources of irrigation water such as surface water from on-farm collection. Understanding the use of alternative water sources for irrigated agriculture in the state can inform policy makers where to invest in surface water infrastructure. Peer networks of irrigation practices can influence the decision of farmers to pursue infrastructure investments in surface water, as well as the financial capital available to them for investments. We use survey responses from Arkansas irrigators to analyze the determinants of the participation and intensity of surface water use.

REU Student: Ms. Lydia Ruben
Project Mentor: Dr. Julian Ferry

When we chlorinate water, we often form what are known as Haloacetic acids, a disinfectant byproduct. These are created when chlorine-based disinfectants meet the organic matter in the water. There are nine Haloacetic acids found in water, but only five of them are regulated by the environmental protection agency. This project focuses on the five regulated Haloacetic acids, but also takes notes of any of the unregulated ones that may appear in the data.

REU Student: Mr. Jesutofunmi Palmer 
Project Mentor: Dr. Jamie Hestekin

Cellulose nanomaterials (CNMs) are derived from plant matter and are comprised of nanoscopic cellulose crystals and fibers. It has a wide and diverse set of applications from cosmetics to oil recovery. This study focuses on the properties of Oxone-mediated TEMPO-Oxidized cellulose nanomaterials (OTO-CNMs) as well as explores the use of OTO-CNMs to control the gas and alkyl ketene dimers(AKD) wax to control the moisture properties of OTO-CNM coated substrates. This research utilized dipping and spraying applications as an innovative methodology to apply OTO-CNM and AKD wax modifications to the surface of polyvinyl difluoride (PVDF) supports. This study hopes to further the research in the application of CNM coating and films used in food products as well as establish an innovative technique to apply such coatings.The cup method, gas transport, SEM microscopy, tensile strength, contact angle, and FTIR Spectroscopy will be used to test the effectiveness of the modified OTO-CNMs

 

REU Student: Ms. Lori Huck
Project Mentor: Dr. Erik Pollock

Phosphorus is a naturally occurring nutrient that can be beneficial toplant and animal life in and around streams, rivers, and lakes. While occurring naturally, phosphorus can also be a by-product of runoff from waste from animal farms, agriculture fertilizer, organic wastes in sewage, as well as runoff from industrial wastes. Normal levels of phosphorus in uncontaminated water is between 0.01 and 0.03mg/L. Levels between 0.025-0.1mg/L stimulate growth of aquatic plants and algae while 0.1mg/L is the maximum acceptable level to avoid accelerated eutrophication. Eutrophication and its consequences are greatly accelerated at levels above 0.1mg/L. We tested several methods for measuring phosphorus to determine 1) How can we quickly, efficiently, and cost effectively measure phosphorus in water ways? 2) and 3) How can we more quickly, efficiently, and cost effectively measure this phosphorus?.

REU Student: Ms. Greta Savitsky
Project Mentor: Dr. Daniel Magoulick

Anthropogenic processes in theOzark Interior Highlands of Arkansas and Missouri have greatly increased the amount of nutrients flowing into stream headwaters. This has the potential to change the nutrient content of the stream ecosystems, affecting both biotic and abiotic aspects of the streams. Primary producers are highly vulnerable to nutrient fluctuations, which can reverberate up the food chain, changing ecosystem dynamics across all trophic levels. Eutrophication, or widespread algal blooms due to high nutrient content of agricultural runoff and other anthropogenic sources, is a well-known process, but less research has been done investigating how increased nutrients affect algae within different types of streams. In the Ozark Highlands, streams are categorized into several different flow regimes based on many aspects, including where water originates. We explore two different headwater stream flow regimes: runoff flashy and groundwater flashy. In this study, I seek to understand algal responses to increased amounts of Nitrogen and Phosphorus in headwater streams and how this differs by flow regime. We found that increased nutrients (nitrogen and phosphorus) had a significant effect on algae growth and that different sites showed different nutrient limitation on algae.

REU Student: Ms. Ella Schultz
Project Mentor: Dr. Michelle Evans-White

Riparian and stream ecosystems can be heavily affected by anthropogenic salinization from various activities such as fertilizing, road salting, and energy resource extraction. Build-ups of excess ions could potentially alter an entire ecosystem, either negatively or positively, if decomposers such as fungi are affected. Fungi play an especially important role in detrital decomposition and carbon transferring through their ability to degrade recalcitrant materials that bacteria alone are unable to process. Therefore, an effect on fungi has the potential to both directly and indirectly alter multiple trophic levels. In this study we utilized a mesocosm experiment to observe the effects of sub-lethal additions of NaCl on aquatic hyphomycetes. Our goal was to better understand what effects anthropogenic salinization have on fungal respiration rates, sporulation rates, and biomass measurements in order to add to the small pool of knowledge about this overlooked topic.