EAST TENNESSEE GEOLOGICAL SOCIETY

May 2020 Virtual Meeting

Monday, May 11, 2020
6:00 - 7:30 pm

Note: ETGS members will receive an email with info for logging into the meeting.

Award Winning Student Presentation

Cities on Karst: Cave Stream Geochemistry Across an Urbanization Gradient

By

Victoria E. Frazier
The University of Tennessee Knoxville, MS Candidate, Research Interests: Geomicrobiology

Abstract

Urban development close to cave entrances and over cave passages potentially exposes cave stream ecosystems to contaminated groundwater and surface runoff. However, chronic contamination levels in urban caves and the relationship between cave stream water quality and proximity to urban areas are not well-studied. Knoxville is the third-largest city in Tennessee, but the influence of urbanization on cave stream water quality in the Knoxville metropolitan area is unknown and limited groundwater well and spring water quality data are available in the region. The city of Knoxville is in the Appalachian Valley and Ridge karst province of East Tennessee, USA, which contains >1400 known caves and is home to several endangered and threatened cave-obligate species. Of the 252 caves in Knox County, approx. 40% are in developed areas. We hypothesized that the proximity of caves to urban development can be used to predict the risk to cave stream water quality. Urbanization risk ratings were assigned to caves based on their distance to urban areas, as designated by the National Land Cover Database. Cave stream water and sediment were sampled over a range of predicted urbanization risk ratings, and elevated concentrations of nutrients and conservative geochemical tracers were used as urban indicators. We found that proximity to urban development correlated to overall increases in chloride, sulfate, potassium, and sodium concentrations in cave streams. Cave stream and groundwater samples showed higher nitrate concentrations than surface streams. To date, cave stream nitrate concentrations did not exceed EPA maximum concentration levels for human health, but several urban sites did reach levels that could negatively impact aquatic life. Differences in land use (e.g., highway vs. residential) also influenced geochemical signatures. These results indicate that the proximity of urban development has a measurable and potentially harmful impact on cave stream water quality.

Biography

Victoria is currently a Master's candidate at the University of Tennessee, Department of Earth and Planetary Sciences College of Arts & Sciences, with a research interest in Geomicrobiology. The field of geomicrobiology explores the interactions between microbial and geochemical processes.

Greetings, and welcome to the May 11, 2020 ETGS virtual meeting. We hope you, your family, and your colleagues are staying healthy and well as we endeavor to "flatten the curve".

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Thank you for your patience and understanding as we try this online format. As always, we welcome and appreciate your feedback and suggestions for improvement.

Page updated May 07, 2020