COMPARATIVE MICROBIAL COMMUNITY DYNAMICS IN A KARST AQUIFER SYSTEM AND PROXIMAL SURFACE STREAM IN NORTHWEST ARKANSAS

Northwest Arkansas has well-developed karst systems, with numerous sinking streams and springs. Karst conduits make it easy for contaminants to enter groundwater systems, degrading the water quality and destroying fragile karst ecosystems. With the increase of urbanization, potential threats in the form of fecal contamination may prove to be more of a problem. The purpose of this research is to compare the difference between microbial communities within two different settings, a karst aquifer and a surface stream. Microbial concentrations at different sampling sites will be compared in different flow conditions and seasons. The microbe community within Blowing Spring Cave and Little Sugar Creek were analyzed for the detection and enumeration of E.coli in water and sediment samples. Samples were also analyzed using PCR and 16s rRNA metagenomic analysis to examine microbial diversity at the species level therefore, allowing for DNA fingerprinting to constrain contaminant sources. Storm event samples will be analyzed for introduction of E.coli and changes in E.coli concentrations and microbial communities during the recession period following storms. Lastly, a dye tracer test will be conducted to constrain the recharge area of the spring.