1 / 18

Determining Favorable Environments for Endolithic Growth From Physics Considerations

Determining Favorable Environments for Endolithic Growth From Physics Considerations. Doug Archer, Dr. David Allred Dept. of Physics and Astronomy Brigham Young University. What’s an Extremophile?. Extremophile’s are organisms that can live in extreme environments

leland
Download Presentation

Determining Favorable Environments for Endolithic Growth From Physics Considerations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Determining Favorable Environments for Endolithic Growth From Physics Considerations Doug Archer, Dr. David Allred Dept. of Physics and Astronomy Brigham Young University

  2. What’s an Extremophile? • Extremophile’s are organisms that can live in extreme environments • Examples are Halophiles, Thermophiles, and Endoliths

  3. Limits on Life • Lack of Liquid Water • Temperature extremes • Ultraviolet Radiation • Soil toxicity • Sparse Energy Resources

  4. Mars Had Water in the Past and Still Has Water Today

  5. Temperature Concerns • Mars’ Temperature range -123C to 20C • Once thought a major concern, the discovery of Extremophiles metabolically active from -15C to 120C has changed our thinking. • Active->Dormant cycle

  6. Ultraviolet Radiation • UVA = 400-315nm • UVB = 315-280nm • UVC = 280-200nm • Below ~290nm, UV energy is very damaging to most biological systems. • It affects proteins, lipids, and most importantly, DNA.

  7. UV Flux, Earth vs. Mars

  8. The Role of Ozone • The Chapman Reaction describes ozone creation/reaction. • Ozone absorbs between 200-360nm • Mars’ ozone layer is <1% of earths at maximum

  9. UV Damage

  10. Surviving UV • There are three primary methods: • Avoidance: chemoautotrophs • Repair: photolyase cuts thymine dimers. Present in modern branches of ancient archaebacteria. • Protection: Matting, Substrate Production, Physical Environment Sheltering.

  11. Why Endoliths? • Endolithic communities, also known as cryptoendoliths, could provide protection from numerous life limiting conditions. • We have ready access to endoliths in the Southern Utah Desert.

  12. Physics Concerns • Which compounds found in common minerals block UV? • This is a function of band gap • Is UV light preferentially absorbed or scattered out of certain materials? Rayleigh vs. Mie scattering • Particle size (<1/10 wavelength=Ray.) • Wavelength Dependence (λ^4 vs λ) • How fast does the intensity drop as a function of depth and wavelength • To what extent is color important and how is it produced?

  13. Martian Minerology

  14. Absorption Example

  15. Correlate and Compare • Minerals with Fe203: • Hematite, Maghemite • Compare to Martian minerals using spectography and terrestrial analogues. • USGS Imaging Spectroscopy • Have found abundant Olivene (Mg1.6Fe2+0.4(SiO4))

  16. Remaining Questions • Can microporosity and capillary action act to prevent or lessen dessication of the cryptoendoliths? • How can we robotically detect the presence of Endoliths?

  17. Conclusions • Given what we know about the early history of Earth and Mars, it is not a stretch to theorize that life appeared simultaneously. Earth provided a more successful habitat, but conditions on Mars do not preclude the continued presence of life. • Endolithic habitats provide a refuge from many of the limiting factors on life as we know it.

More Related