Phototrophic purple sulfur bacteria as heat engines in the South Andros Black Hole

Rodney A. Herbert, Andrew Gall, Takashi Maoka, Richard J. Cogdell, Bruno Robert, Shinichi Takaichi, Stephanie Schwabe

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    10 Citations (Scopus)

    Abstract

    Photosynthetic organisms normally endeavor to optimize the efficiency of their light-harvesting apparatus. However, here we describe two bacterial isolates belonging to the genera Allochromatium and Thiocapsa that demonstrate a novel adaptation by optimizing their external growth conditions at the expense of photosynthetic efficiency. In the South Andros Black Hole, Bahamas, a dense l-m thick layer of these anoxygenic purple sulfur bacteria is present at a depth of 17.8 m. In this layer the water temperature increases sharply to 36 degrees C as a consequence of the low-energy transfer efficiency of their carotenoids (ca. 30%). These include spirilloxanthin, and related polyene molecules and a novel chiral carotenoid identified as spirilloxanthin-2-ol, not previously reported in purple bacteria. To our knowledge, this study presents the first evidence of such a bacterial mass significantly increasing the ambient water temperature. The transduction of light to heat energy to excess heat may provide these anoxygenic phototropic bacteria with a competitive advantage over non-thermotolerant species, which would account for their predominance within the microbial layer.
    Original languageEnglish
    Pages (from-to)261-8
    Number of pages8
    JournalPhotosynthesis Research
    Volume95
    Issue number2-3
    DOIs
    Publication statusPublished - 2007

    Keywords

    • Carotenoids
    • Chromatiaceae
    • Chromatography, High Pressure Liquid
    • Light Signal Transduction
    • Nuclear Magnetic Resonance, Biomolecular
    • Photosynthesis
    • Spectrometry, Fluorescence
    • Temperature

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  • Cite this

    Herbert, R. A., Gall, A., Maoka, T., Cogdell, R. J., Robert, B., Takaichi, S., & Schwabe, S. (2007). Phototrophic purple sulfur bacteria as heat engines in the South Andros Black Hole. Photosynthesis Research, 95(2-3), 261-8. https://doi.org/10.1007/s11120-007-9246-1