MICROBIAL COMPOSITION OF MINING-CONTAMINATED AND REMEDIATED SOILS IN THE MISSOURI TRI-STATE MINING DISTRICT

The Tri-State mining district of southwest Missouri, southeast Kansas, and northeast Oklahoma experienced over 100 years of metal mining. This mining ended in the 1970s and remediation started in 1984. However, many abandoned and former mines remain and contribute to widespread metal contamination. The area's karst topography means metal pollution is transported easily via waterways. Metals accumulate in the sediment or enter the food chain where they are toxic. The Tri-State mining district is primarily affected by zinc and lead pollution and many remediation methods have been utilized. There is a growing interest in using plants and microbes in combination for bioremediation, which has shown to be successful. However, plant microbial communities and their relationship to metal concentrations of remediated areas in the tri-state area is poorly understood. Plants manipulate their rhizosphere microbiome in response to stressors and recruit certain microbes to increase metal tolerance. Microbes in polluted and remediated areas vary depending on the metal, extent of pollution, and various soil characteristics such as pH. The bacteria capable of remediating an area is site-specific and identifying local remediating bacteria can expedite remediation efforts. We will collect rhizosphere and bulk soils associated with Andropogon virginicus (bluestem broomsedge) from sites in Webb City, MO that are of varying stages of remediation (remedial to restored prairie) and never remediated. Rhizosphere soil is the soil that is adhered to plant roots. Bulk soil is defined as soil not associated with the plant roots. We will use next-generation Illumina MiSeq paired-end DNA sequencing to evaluate the bacterial community and ICP-MS to measure metal concentrations in the rhizosphere and bulk soils. I hypothesize that (1) there will be less bacterial diversity and abundance in the rhizosphere soil than the bulk soil and (2) species diversity and abundance will increase as metal concentrations decrease in remediated sites.