 Photo credit: Dr Serguei M. Pershin |
Russian Scientist Finds Organic Pigments on Marsby Barry E. DiGregorio |
Dr. Serguei M. Pershin PhD, a Principal Investigator for the NASA Mars Polar Lander LIDAR experiment, Russia's first experiment on a US spacecraft claims he has discovered organic pigments on Mars relating to ancient photosynthetic organisms. ICAMSR Executive Director, Barry E. DiGregorio has written an exclusive article about his discovery in the September issue of Spectroscopy magazine. Why is the discovery of organic pigments on Mars so important for the science of exobiology? Because it might still be there today and perhaps that is what Dr. Gilbert V.Levin and Dr. Patricia Ann Straat found in their experiment 24 years ago with NASA's Viking Mars spacecraft.
On Mars, during the Hesperian period of postulated oceans, lakes and rivers, there would have been sufficient energy input from solar radiation to support life with the characteristics of the cyanobacteria that dominate many terrestrial and aquatic habitats on Earth, e.g. the cold deserts in Antarctica. The key to the survival of cyanobacteria are in part due to the pigments they have such as:
- Chlorophyll for converting solar radiation into food (photosynthesis).
- Cyanobacteria can tolerate the extreme damaging effect of solar UV-B by synthesising a variety of protecting pigments which either screen or prevent the effect of the radiation, such as phycocyanin, scytonemin, mycosporine- like amino acids, carotenoids and isoprenoids.
The pigments Dr. Pershin may have found are porphyrins derived from chlorophyll and hopanoids from carotenoids. These are found in cyanobacterial sedimentary deposits 3.5 Gy old. These photosynthetic pigments are auto-fluorescent and all biomolecules have unique spectra which can be detected amongst other compounds within a community. Dr. Pershin has used a two-band, red/green radiance-ratio technique as a tool for detecting evidence of pigments and related compounds derived from any cyanobacteria-like organisms in sediments residual from possible former potential habitats on the surface of Mars covering a rather large area in the western Utopia Planitia region of Mars. It is well known that organic pigments and components have a visible and red part in flourescence spectrum under the laser and solar UV-visible excitation. Several Hubble Space Telescope images of Mars were taken in key wavelengths and were used in his analysis. The question is: Are these pigments ancient or recent?
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