HR: 1340h
AN: B13A-1050    [Abstracts]
TI: Microbial Diversity and Population Structure of Extremely Acidic Sulfur-Oxidizing Biofilms From Sulfidic Caves
AU: * Jones, D
EM: jonesd@carleton.edu
AF: Carleton College, Geology Dept., Northfield, MN 55057 United States
AU: Stoffer, T
EM: tstoffer@gmail.com
AF: Pennsylvania State Univ., Dept. of Geosciences, University Park, PA 16802 United States
AU: Lyon, E H
EM: elyon@geosc.psu.edu
AF: Pennsylvania State Univ., Dept. of Geosciences, University Park, PA 16802 United States
AU: Macalady, J L
EM: jmacalad@geosc.psu.edu
AF: Pennsylvania State Univ., Dept. of Geosciences, University Park, PA 16802 United States
AB: Extremely acidic (pH 0-1) microbial biofilms called snottites form on the walls of sulfidic caves where gypsum replacement crusts isolate sulfur-oxidizing microorganisms from the buffering action of limestone host rock. We investigated the phylogeny and population structure of snottites from sulfidic caves in central Italy using full cycle rRNA methods. A small subunit rRNA bacterial clone library from a Frasassi cave complex snottite sample contained a single sequence group (>60 clones) similar to Acidithiobacillus thiooxidans. Bacterial and universal rRNA clone libraries from other Frasassi snottites were only slightly more diverse, containing a maximum of 4 bacterial species and probably 2 archaeal species. Fluorescence in situ hybridization (FISH) of snottites from Frasassi and from the much warmer Rio Garrafo cave complex revealed that all of the communities are simple (low-diversity) and dominated by Acidithiobacillus and/or Ferroplasma species, with smaller populations of an Acidimicrobium species, filamentous fungi, and protists. Our results suggest that sulfidic cave snottites will be excellent model microbial ecosystems suited for ecological and metagenomic studies aimed at elucidating geochemical and ecological controls on microbial diversity, and at mapping the spatial history of microbial evolutionary events such as adaptations, recombinations and gene transfers.
DE: 0448 Geomicrobiology
DE: 0456 Life in extreme environments
DE: 0463 Microbe/mineral interactions
DE: 0465 Microbiology: ecology, physiology and genomics (4840)
DE: 0488 Sulfur cycling
SC: Biogeosciences [B]
MN: Fall Meeting 2005