129-40 Who Moved My Soil: Microbial Ecology and Soil Geochemistry Across Landslide and Reference Settings at Floracliff Nature Sanctuary, Kentucky

Abstract:

Who Moved My Soil: Microbial Ecology and Soil Geochemistry Across Landslide and Reference Settings at Floracliff Nature Sanctuary, Kentucky

Mamie Clark¹, Jason Backus¹, Andrea Connor¹, and Rachel L. Washburn²

¹Kentucky Geological Survey, University of Kentucky, Lexington, Kentucky, USA

²Kentucky Geological Survey and College of Pharmacy, University of Kentucky, Lexington, Kentucky, USA

Landslides are among the most common and damaging geologic hazards in Kentucky (USA), causing millions of dollars in infrastructure and property damage each year. Soil microbial communities can influence erosion, water infiltration, and soil aggregation through processes including biocrust formation and the production of extracellular polymeric substances (EPS). Although slope stability is generally evaluated using geologic, hydrologic, and geotechnical factors, the potential contribution of soil microbial communities remains poorly understood. We hypothesized that landslide-associated soils contain distinct microbial communities and geochemical characteristics relative to non-landslide reference soils. Surface soils were collected using sterile field techniques from four geomorphic settings at Floracliff Nature Sanctuary (Lexington, Kentucky, USA) approximately 11 months after an April 2025 landslide: the landslide deposit, landslide scarp (1 meter from landslide), reference hillslope (7 meters from landslide), and reference floodplain (900 meters from landslide). Soil mineralogy and elemental composition were characterized using X-ray diffraction (XRD) and X-ray fluorescence (XRF). Prokaryotic and eukaryotic communities were characterized using 16S and 18S rRNA gene sequencing, respectively. Alpha- and beta-diversity analyses were used to evaluate diversity within each setting and differences in community composition among settings. Preliminary results indicate that microbial community composition and soil geochemistry differ between landslide-associated and reference soils, and each geomorphic setting exhibited distinct microbial and geochemical characteristics despite the close spatial proximity of all four settings. Ongoing metabolomic analyses and molecular networking will evaluate secondary metabolites with potential roles in soil aggregation and stabilization. These results demonstrate associations among geomorphic setting, microbial community composition, and soil geochemistry. Future work will apply this approach across multiple landslides and reference sites to determine whether the observed microbial and geochemical patterns are consistent across landscapes and associated with measurable differences in soil stability. This work provides a foundation for testing whether biological processes contribute to slope stability and could eventually inform soil stabilization strategies.

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