Photosynthesis Research

, Volume 95, Issue 2, pp 261–268

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
Regular Paper

DOI: 10.1007/s11120-007-9246-1

Cite this article as:
Herbert, R.A., Gall, A., Maoka, T. et al. Photosynth Res (2008) 95: 261. doi:10.1007/s11120-007-9246-1

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°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.

Keywords

Anoxygenic purple sulfur bacteria Allochromatium Thiocapsa South Andros Black Hole Carotenoid Spirilloxanthin Energy-transfer 

Supplementary material

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Rodney A. Herbert
    • 1
  • Andrew Gall
    • 2
  • Takashi Maoka
    • 3
  • Richard J. Cogdell
    • 4
  • Bruno Robert
    • 2
  • Shinichi Takaichi
    • 5
  • Stephanie Schwabe
    • 6
  1. 1.Division of Environmental and Applied Biology, School of Life SciencesUniversity of DundeeDundeeUK
  2. 2.Institut de Biologie et Technologies de SaclayCommissariat à l’Energie AtomiqueGif sur YvetteFrance
  3. 3.Research Institute for Production DevelopmentSakyou-kuJapan
  4. 4.Institute of Biomedical and Life SciencesUniversity of GlasgowGlasgowUK
  5. 5.Biological LaboratoryNippon Medical SchoolNakaharaJapan
  6. 6.International Blue Holes FoundationCharlestonUSA

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