Hydrothermal ecotones and streamer biofilm communities in the Lower Geyser Basin, Yellowstone National Park

Authors

  • D'Arcy R Meyer-Dombard,

    Corresponding author
    1. Department of Earth, Atmospheric, and Environmental Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
      E-mail drmd@uic.edu; Tel. (+1) 312 996 2423; Fax (+1) 312 413 2279.
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    • Present address: Department of Earth and Environmental Sciences, University of Illinois at Chicago, 845 W. Taylor, Chicago, IL, 60515, USA.

  • Wesley Swingley,

    1. School of Natural Sciences, University of California Merced, Merced, CA, USA.
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  • Jason Raymond,

    1. School of Natural Sciences, University of California Merced, Merced, CA, USA.
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  • Jeff Havig,

    1. School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.
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  • Everett L Shock,

    1. School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.
    2. Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, USA.
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  • Roger E Summons

    1. Department of Earth, Atmospheric, and Environmental Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
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E-mail drmd@uic.edu; Tel. (+1) 312 996 2423; Fax (+1) 312 413 2279.

Summary

In Yellowstone National Park, a small percentage of thermal features support streamer biofilm communities (SBCs), but their growth criteria are poorly understood. This study investigates biofilms in two SBC hosting, and two non-SBC springs. Sequencing of 16S rRNA clones indicates changing community structure as a function of downstream geochemistry, with many novel representatives particularly among the Crenarchaeota. While some taxonomic groups show little genetic variation, others show specialization by sample location. The transition fringe environment between the hotter chemosynthetic and cooler photosynthetic zones hosts a larger diversity of organisms in SBC bearing springs. This transition is proposed to represent an ecotone; this is the first description of an ecotone in a hydrothermal environment. The Aquificales are ubiquitous and dominate among the Bacteria in the hottest environments. However, there is no difference in species of Aquificales from SBC and non-SBC locations, suggesting they are not responsible for the formation of SBCs, or that their role in SBC formation is competitively suppressed in non-SBC sites. In addition, only SBC locations support Thermotogales-like organisms, highlighting the potential importance these organisms may have in SBC formation. Here, we present a novel view of SBC formation and variability in hydrothermal ecosystems.

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