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Water Quality in Karst: Bacterial Movement in the Cane Run Watershed. Ashley Bandy Department of Earth and Environmental Sciences University of Kentucky June 25, 2014. Why Should We Care?. Water can transmit pathogens Bacterial transport in karst is not well understood
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Water Quality in Karst:Bacterial Movement in the CaneRun Watershed Ashley Bandy Department of Earth and Environmental Sciences University of Kentucky June 25, 2014
Why Should We Care? • Water can transmit pathogens • Bacterial transport in karst is not well understood • Ward (2008) showed that 15N-tagged Escherichia coli had more tailing than solute tracers and were not remobilized like microspheres • More work is needed to understand bacterial and pathogen transport
What is karst? • 15% of the contiguous U.S. • Characterized by sinkholes, caves, springs, and disappearing streams • Corvette Museum near Bowling Green! • Occurs in regions of soluble rock (such as limestone) • Dissolution
1 2 3 4 5 Unknown Spring Water Movement in Karst • Conduits and groundwater flow paths can be complex • Groundwater flow is turbulent instead of laminar • This mixing motion can stir up particles in the water and transport them greater distances (Currens, 2010)
Water Quality • Water is not filtered in karst environments like it is in other areas…
Cane Run and Royal Spring • Cane Run watershed drains 115 km2 through urban and rural land • 30% of homes have faulty/no septic system • Cane Run is on KY’s 303(d) list of impaired streams (fails to meet water quality standards) • Royal Spring provides drinking water to the cities of Georgetown, Lexington, Sadieville, Stamping Ground, and Midway
The groundwater basin does not coincide with the surface watershed
Objectives • Evaluate transport of 15N-labelled E. coli within the Cane Run-Royal Spring basin • Examine transport properties of two different isolates of through epikarst • S1 (high attachment with iha gene) vs. S10 (low attachment with the kps gene) • How does bacterial movement compare to dyes and microspheres?
Isotopes • Differing number of neutrons • Compares the ratio of the rare isotope to the common isotope in a sample to that of a standard • Nitrogen standard is air, with a 15N/14N value of 0.0036765
PCR • Polymerase chain reaction • cycles of denaturation, primer annealing, and primer elongation are used to amplify DNA sequences of interest
5’ 3’ 3’ 5’ 5’ 3’ 3’ 5’ 5’ 3’ 3’ 5’ 5’ 3’ 3’ 5’ 5’ 3’ 3’ 5’ Target sequence amplified
Methods (Royal Spring) • Background values monitored • Water collected using an integrated depth sampler and autoclaved bottles • 6 L total (3 for molecular and 3 for isotopes) • Molecular samples are filtered onto Polycarbonate filters with 0.4μm pore size • Isotope samples are filtered onto glass fiber filters with 0.5μm pore size • Note values such as temp., pH, DO, conductivity
Expected Outcomes • Particulate tracers (microspheres and E. coli) will precede fluorescent dyes under base flow conditions in the Royal Spring basin • similar to Auckenthaler et al. 2002, Ting et al. 2005, Goldschieder et al. 2006, and Göppert and Goldscheider 2008 • E. coli will arrive prior to microspheres • E. coli will exhibit remobilization with subsequent storms
Conclusions • Information gained about bacterial transport during the traces should provide insight on transport in karst environments • Compare movement of bacteria to commonly used tracers • Identify possible transport differences among two E. coli isolates
Teacher Resources • Kentucky Geological Survey • Free maps! • Open Houses • Other resources • Project WET Curriculum Guide • Great lesson plans for all grades • Me (Graham Cracker Plate Tectonics lab)
Acknowledgements • Funding provided by: • Dr. Steve Workman, UK College of Agriculture • Agriculture and Food Research Initiative, USDA National Institute of Food and Agriculture • Consortium of Universities for the Advancement of Hydrologic Science, Inc. • Cave Research Foundation
Questions? Stay in touch! Email me at amba229@uky.edu