Heavy Metal Chemistry of Sediments in Caves of the Springfield Plateau, Missouri-Arkansas-Oklahoma: A Link to Subterranean Biodiversity

Abstract

We used X-ray fluorescence (XRF) to compare the heavy metal chemistry of sediments in caves in rural and urban areas to the chemistry of sediments from a control cave in a relatively undisturbed watershed in the Springfield (MO) Plateau. Sediment from Smallin Cave near Ozark, MO, the control cave, has the smallest peak sizes for Zn and Mn and a moderately-sized Pb peak. Sediment from the rural cave exhibited larger peaks of Zn and Mn and a smaller Pb peak. Sediment from the urban cave had the largest Zn, Mn and Pb peaks. Interestingly, smaller peak sizes appear to correlate to the presence of aquatic troglobites. The control cave hosts the most diverse troglobitic fauna and has sediment with smaller peak sizes. Ruark caves are rural caves, and are barren of troglobites and have sediment with larger peak sizes. Giboney Cave, an urban cave in Doling Park in Springfield, MO, provides the most interesting evidence. Giboney Cave splits into two branches, each of which has a unique chemical fingerprint. One channel is barren of cave life and has sediment that exhibits large metal peaks. The second channel hosts aquatic troglobites and has sediment that has small metal peaks. These findings are of particular importance because the caves of the Springfield Plateau host abundant troglobitic species, including the endangered Ozarks cavefish (Amblyopsis rosae). Sediment metal concentrations may indicate which cave systems are capable of supporting life, with XRF analysis providing a non-destructive, rapid way to identify such systems.