A microbial diversity survey of a natural iron seep within Big Bend Ranch State Park, Texas

• Main Author: Green, Julia Elizabeth
• Language: EN
• Published: Sul Ross State University 2017
• Subjects: Microbiology
• Online Access: http://pqdtopen.proquest.com/#viewpdf?dispub=10249414

<p> A perpetual spring containing an orange biofilm composed of microbial sheaths was examined utilizing both geochemical and biological techniques. Big Bend Ranch State Park, the largest state park in Texas, covers over 120,000 hectares in the Chihuahuan Desert. While most surface features in this rugged, remote, and unpopulated setting are volcanic, underlying sedimentary features are found throughout the area. The presence of an orange biofilm containing a matrix of microbial sheaths was observed at two distinct springs within the park: Las Cuevas Amarillas and Ojo Mexicano. These springs contain low concentrations of hydrocarbons and abundant iron oxides in the water. This study presents the results of a biological analysis of the Las Cuevas Amarillas site in order to better understand the microbial consortia and metabolic strategies associated with these unique microbes. Basic chemical analysis of the water and soil of the site, and scanning electron microscopy with energy- dispersive x-ray spectroscopy analysis and x-ray diffraction analysis of the sheaths themselves, were performed. Total DNA was extracted from the biofilm matrix and universal primer set combinations were utilized to amplify both bacterial and archaeal 16s rRNA genes. These amplicons were subsequently cloned, sequenced, and phylogenetically analyzed. High-throughput sequencing (Roche 454 platform) was also performed in order to provide a deeper data set and a better representation of the diversity within this site. These analyses revealed numerous <i>Sphaerotilus</i> and <i>Leptothrix</i> spp., both genera known to be capable of sheath production. Iron- and manganese-oxidizing bacteria were determined to be abundant. Other beta- and gamma-proteobacteria, including <i>Thiobacillus</i> spp., <i>Curvibacter</i> spp., <i>Ideonella</i> spp., <i>Chromatiaceae</i> spp. and both Crenarchaeota and Euryarchaeota, were also detected.</p>