Original research is a key element of the graduate school experience. Through this experience, a students learns how to define a problem, design an investigation to study the problem, conduct the investigation, analyze and interpret the results, and defend their work in a public forum and in a written document.
Below are some examples of ongoing or recently completed research projects being conducted by graduate students in the department.
Advisors: Steve Van der Hoven and Bill Perry (Dept. of Biological Sciences)
Phosphorous is often a limiting nutrient for biological productivity in aquatic systems. However, runoff from fertilized agricultural fields and treated waste water effluent can increase the amount of phosphorous in streams and lakes. The increased nutrient load can result in higher biological productivity and depletion of oxygen in surface water. Oxygen depletion can have detrimental effects on aquatic ecology.
Katie's research focuses on the role of stream sediments in the phosphorous cycle. Phosphorous concentrations is surface waters are generally low (20-50 µg/L
as DRP) because in part because it binds to stream sediments. Thus, the amount of phosphorous bound to sediments is usually much larger than the amount dissolved in water. Most sediment phosphorous is adsorbed to Fe and Al hydroxide minerals and co-precipitated with carbonate minerals.
The primary hypothesis of Katie's research is that there will be seasonal variations in amount of phosphorous adsorbed to the Fe/Al hydroxide fraction. This sediment will be available for biological activity because adsorption and desorption are rapid processes. Plants uptake of phosphorous dissolved in water will be replaced by desorption of phosphorous from Fe/Al hydroxides. Thus, during the growing season, the amount of phosphorous adsorbed to Fe/Al hydroxides will decrease. During the non-growing season, Fe/Al-bound phosphorous will increase due to inputs from soil erosion from agricultural fields during storm events.
Katie's research is being conducted in conjunction with Bill Perry and graduate students in the Department of Biological Sciences. The biological studies focus on algal primary productivity which is hypothesized to correlate with changes in sediment-bound phosphorous. This research is funded by the Illinois Department of Agriculture's Council for Agricultural Research program. Katie presented the results of her research to date at the Geological Society of America meeting in October, 2005, and at the North American Benthological Society Meeting in June, 2006.
Advisor: Eric Peterson
Tim conducted research tested the hypothesis that velocity differences perpendicular to the direction of stream flow could cause pressure differences that result in surface water/ground water exchange. In his own words, "Can flowing water in a stream suck water out of the ground?"
Tim formulated his question on Bernoulli's conservation of energy equation, which states that the energy of moving water is divided into gravitational and velocity components. At any point in a stream (i.e. the inside and outside of a meander), the total energy is the same. However, if the velocity components differ, then the gravitational (or pressure head) components must differ in order to conserve energy. So, the velocity differences may cause pressure head differences which may cause the flow of water across the stream bed.
To address his question, Tim installed nested peizometers in the stream bed and the stream banks, and has equipped them with pressure transducers. Tim's data indicate that the velocity differential observed in the stream may be to low to produce a measurable pressure difference. The work has provided an initial study from which to build, including the possibility of numerical modeling of the exchange. While Tim's work focused on two dimensions, future students will focus on three dimensions. Tim's research is funded by the Geological Society of America and Sigma Xi.
Advisor: Eric Peterson
In karst terrain, ground water is especially vulnerable to contamination from land-use activities because of the direct and rapid hydrologic link between surface water and ground water. When impacted surface water enters swallet or storm-water runoff flows into a sinkhole, contaminants enter the ground water directly. The direct connection to the ground water eliminates the possibility of soil filtration, degradation, and sorption of the contaminant.
Karst aquifers are vulnerable to surface water impact. Assessing the risks to a karst system requires knowledge of the sources as well as the pathways the water flows. Unlike traditional porous media aquifers, karst systems are complex due to flow along bedding planes, fractures, and conduits. Understanding the flow with karst aquifers is an important step in preserving the integrity of the system, including the biological habitat.
Julie's research focuses on identifying the various sources and pathways for the water of moving through the Horn Hollow system in Carter Caves State Park in Kentucky. Julie has collected some preliminary data and is in her initial stages of forming her hypothesis. Major ion samples were collected from 15 locations within the Horn Hollow Valley at baseline flow conditions and after a precipitation event. Fluxes of Ca2+ and Mg2+ were observed as the karst waters entered and exited the subsurface. Water types are dominantly Ca-HCO3 with two distinct subgroups based on major ion chemistry. The upstream portion of the system contains aggressive waters (Ca-Mg-HCO3-SO4) that are under-saturated with respect to Ca2+. Less aggressive waters (Ca-HCO3) are present in the downstream portion of the system, which includes Laurel Cave and Cave Branch, and are over-saturated with respect to Ca2+. The increase in saturation with respect to Ca2+ through the system may be the result of limestone dissolution, a change in concentration of CO2, or a change in temperatures as waters flow through the system. Mass flux calculations of Ca2+ and Mg2+ will be performed to determine dissolution rates within the upper Horn Hollow system.
Advisors: Dave Malone and Eric Peterson
The Ticona Channel is a part of the pre-glacial drainage system in Illinois that has been buried by glacial sediments. Coarse-grained sediments fill the bottom of the valley, forming a potentially valuable aquifer for nearby communities. The objective of Bryce's research is to define the geometry of the channel, map the sediments that fill the channel, measure aquifer properties of the coarse-grained sediments, and examine the interaction of channel sediments with the nearby Vermillion River.
Bryce employed a wide variety of techniques to conduct his investigation. These techniques include s-wave geophysics, borehole geologic and geophysical logging, surface geologic mapping, and groundwater modeling.
Bryce's research was funded by the Illinois Board of Higher Education through the Illinois State Geological Survey (ISGS), and by a United States Geological Survey EDMAP grant. His research is a part of a larger collaboration between the department and the ISGS. Over the past two years, numerous undergraduate and graduate students have collaborated with ISGS scientists on geologic, geophysical, and geochemical investigations of buried valley aquifers throughout Illinois. Bryce has submitted the results of his research for publication, and is currently pursuing a Ph.D. at Northern Illinois University.
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