Owl Cave is far downstream in the Turnhole Spring Basin, which extends far beyond park boundaries in the Sinkhole Plain with agriculture, oil and gas wells, Interstate Highway 65, and the CSX Railroad. Therefore contaminants of several types pass through the stream in Owl Cave. Natural backflooding events from Green River, and events caused by dam releases upstream are also a factor. For many years I have observed a heavy biofilm on rocks in the stream, which suggests organic enrichment. There is also a lack of cave adapted life, which might be partially accounted for by daylight hitting the stream, but even surface isopods have been absent so toxins may be at least sporadically present.
Hypothesis: Organic enrichment, possibly from livestock operations, has resulted in a heavy eutrophic biofilm with a different microbial assemblage from that found in unimpacted similar sites. Secondary hypothesis: Pulses of toxic substances periodically reduce populations of aquatic cave life.
One gram (approximately 30 count) of limestone Bio-Sep beads were deployed in triplicate and retrieved after one year in 2005. DNA was extracted from the beads and analyzed by quantitative Real-Time PCR with universal eubacterial primers. PCR products were characterized by cloning and sequencing with phylogenetic analysis. Data are summarized in the links below.
Clone distributions and quantitative data by Rick Fowler using sequence data from biofilm clones identified with the Ribosomal Database Project classifier tool, qRT-PCR, and lipid analysis.
Classification table and phylogenetic treeby Hazel Barton and Brandon Iker at Northern Kentucky University (www.cavescience.com) using Eubacterial 16S SSU-DNA sequence data from bead biofilms developed during 2005.
Owl Cave FASTA files from 2005