2012/10/15 by Annette Summers Engel, Lindsey R. Johnson, Megan L. Porter · 5 citations
Environmental Science · #Arsenic contamination and mitigation #Microbial Community Ecology and Physiology #Mine drainage and remediation techniques #Biology #Arsenite #Chloroflexi (class) #Arsenic #Firmicutes #Phylogenetic diversity #Phylogenetic tree #Gene #Arsenate #Proteobacteria #Genetics #16S ribosomal RNA #Ecology
paper · pdf · doi:10.1111/1574-6941.12030
openalex publication_date 2012/10/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Arsenic concentrations (450-600 μmol L(-1)) at the El Tatio Geyser Field in northern Chile are an order of magnitude greater than at other natural geothermal sites, making El Tatio an ideal location to investigate unique microbial diversity and metabolisms associated with the arsenic cycle in low sulfide, > 50 °C, and circumneutral pH waters. 16S rRNA gene and arsenite oxidase gene (aioA) diversities were evaluated from biofilms and microbial mats from two geyser-discharge stream transects. Chloroflexi was the most prevalent bacterial phylum at flow distances where arsenite was converted to arsenate, corresponding to roughly 60 °C. Among aioA-like gene sequences retrieved, most had homology to whole genomes of Chloroflexus aurantiacus, but others were homologous to alphaproteobacterial and undifferentiated beta- and gammaproteobacterial groups. No Deinococci, Thermus, Aquificales, or Chlorobi aioA-like genes were retrieved. The functional importance of amino acid sites was evaluated from evolutionary trace analyses of all retrieved aioA genes. Fifteen conserved residue sites identified across all phylogenetic groups highlight a conserved functional core, while six divergent sites demonstrate potential differences in electron transfer modes. This research expands the known distribution and diversity of arsenite oxidation in natural geothermal settings, and provides information about the evolutionary history of microbe-arsenic interactions.