Microbial rock inhabitants survive hypervelocity impacts on Mars-like host planets: First phase of lithopanspermia experimentally tested

Gerda Horneck, Dieter Stoeffler, Sieglinde Ott, Ulrich Hornemann, Charles S. Cockell, Ralf Moeller, Cornelia Meyer, Jean-Pierre De Vera, Joerg Fritz, Sara Schade, Natalia A. Artemieva

Research output: Contribution to journalArticlepeer-review

Abstract

The scenario of lithopanspermia describes the viable transport of microorganisms via meteorites. To test the first step of lithopanspermia, i. e., the impact ejection from a planet, systematic shock recovery experiments within a pressure range observed in martian meteorites (5-50 GPa) were performed with dry layers of microorganisms ( spores of Bacillus subtilis, cells of the endolithic cyanobacterium Chroococcidiopsis, and thalli and ascocarps of the lichen Xanthoria elegans) sandwiched between gabbro discs ( martian analogue rock). Actual shock pressures were determined by refractive index measurements and Raman spectroscopy, and shock temperature profiles were calculated. Pressure- effect curves were constructed for survival of B. subtilis spores and Chroococcidiopsis cells from the number of colony-forming units, and for vitality of the photobiont and mycobiont of Xanthoria elegans from confocal laser scanning microscopy after live/dead staining (FUN-I). A vital launch window for the transport of rock-colonizing microorganisms from a Mars-like planet was inferred, which encompasses shock pressures in the range of 5 to about 40 GPa for the bacterial endospores and the lichens, and a more limited shock pressure range for the cyanobacterium ( from 5-10 GPa). The results support concepts of viable impact ejections from Mars-like planets and the possibility of reseeding early Earth after asteroid cataclysms.

Original languageEnglish
Pages (from-to)17-44
Number of pages28
JournalAstrobiology
Volume8
Issue number1
DOIs
Publication statusPublished - 21 Feb 2008

Keywords

  • lithopanspermia
  • impact
  • shock pressure
  • ejecta
  • microbial survival
  • interplanetary transfer of life
  • BACILLUS-SUBTILIS SPORES
  • BACTERIAL-SPORES
  • MARTIAN METEORITES
  • SPACE ENVIRONMENT
  • ASTEROID IMPACTS
  • EARLY EARTH
  • PANSPERMIA
  • RESPONSES
  • EJECTION
  • ORIGIN

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