1 Noachian Life An Overview of Prevailing Theories, Studies, & Experiments Surrounding Ancient Martian Life By Mike Morgan 2 The Noachian 3 4 Noachian Climate 5 Northern Plains Arabia Shoreline East of Cydonia Mensae 6 Evaporite in Merdiani Outcrop Burns Cliff of Meridiani Outcrop 7 ALH84001 • Igneous Age of 4.091 + or – 0.030 billion years (Noachian) • Carbonate globules may be microscopic fossils of Martian bacteria. – Shown to have formed at 18 degrees celsius – Morphology is not enough. 8 Tissint Meteorite • Recovered almost immediately after impact as well as a thick fusion crust. – Solidified 400 – 500 MYA – Similar carbonate gobules to ALH84001 – Oxygen and Carbon rich disc-shaped structures typically 20 nm in radius. A Dimmer Solar System • Noachian Solar Luminosity 75% that of Today (Gough, 1981) • Contemporary Average Temperature – 60 degrees C ( Ranges from – 125 degrees C to 20 degrees C) • 100 Times Thinner Atmosphere than Earth – 95% CO2 – 10 Degrees • How do we explain the presence of liquid water with lower solar radiation and what are the subsequent effects on climate? 9 10 11 12 Noachian Mars 13 Evidence of Sulfuric Atmosphere • Modeled using Gusev Crater basalt composition and batch melting model. • Soils from landed missions have sulfate abundances of 3 – 10% – “Flat-lying sedimentary rocks rich in sulfur and contain abundant sulfur salts.” (Squyres et al., 2004) • SNC Meteorites – Contain Sulfur – Negative Isotopic Readings Show Sulfur was produced by Atmospheric Chemical Reactions • (Farquhar et al., 2000) 14 15 16 Impacts of Sulfuric Atmosphere on Habitability • Decreases pH of Ocean waters from deposition – Some estimates as low as a pH of 2 -3 based on 3+ presence of Jarosite: KFe 3(OH)6(SO4)2 • Requires a wet, oxidizing, acid environment • Prevents Deposition of Carbonate • Only last 600 Days, warming effect lasts hundreds of years (Wong, 2004). – Is this Enough for Life to Evolve? – Long-lasting intervals of cold, dry conditions 17 Sulfate-Reducing 0 • 2S + 2H2O + SO2 > 2H2SO4 - - - • H2S + 4OH > SO2 + 6H + 8 e • Bacteria in Siberian Permafrost suggests low-level metabolic activity. • Cells persisted under cold conditions for .5 million years. Extremophile 18 19 ERODED NOACHIAN CRATERS 20 Holden Crater Yellowknife Crater • Curiosity Rover • Once contained Ancient lake that could have supported Martian biosphere founded on chemolithautotrophs. – Low Salinity and sediment- transporting water. – Uses inorganic compounds for energy – Sheepbed Mudstone is believed to be sequestered fine sediments over long periods of time. • Nodules, microbial fossils? • 1500 – millions of years 21 A Promising Crater – Nutrients • Carbon • Hydrogen • Sulfur • Nitrogen • Phosphorous – All found in Gale Crater – Plausible Redox Couples • Sulfur and Iron • Inorganic Volatiles • Higher proportion of reduced sulfur relative to oxidized sulfur points to a plausible redox couple for prokaryotic respiration. 22 Sulfate-Reducing 0 • 2S + 2H2O + SO2 > 2H2SO4 - - - • H2S + 4OH > SO2 + 6H + 8 e 23 24 25 Viking Perchlorate Respiration 26 27 Methanogenic Life • Presence of Methane in Martian Atmosphere reflective of Ancient Noachian Life? • Geologic Processes Trapped Methane Produced by Ancient Methanogenic Life Forms, which becomes slowly released overtime. • Consumes Carbon Dioxide and Respires Methane 28 Future Missions 29 30 ExoMars • Curiosity Spectrometer Detected Carotenoid Molecules – Protects from Radiation – Biosignature of past life? • ExoMars will drill 2 meters deep in Noachian Site – Searching for Biomarkers • Urey Instrument – Mars Organic and Oxidant Detector – Grind up samples of Martian Soil. – Determine Current Habitability of Martian Soil. Proposed Experiments 31 Microbes and Basaltic Glass • Basaltic Glass • Hyaloclastites + subaqueous basalts. • Microbes rapidly colonize along the surface’s fractures and racks that are exposed to water after cooling. – This colonization alters and modifies the surface and produces characteristic granular or tubular biolateration textures. – Silicates can help preserve these markings for geologic time scales. – Terrestrial glass bioalteration can extend as far back as 3.5 billion 32 years ago. • Microbes filter in through cracks within water, feeding off carbon, nitrogen, and phosphorous from the glass. • Overtime becomes locked in by mixture of minerals and respired materials. 33 Detecting Past Life • Lipid Biomakers – 2700 million-year-old Shales from Pilbara Craton, Australia (Brocks, 1999) – Lipid Biomakers were found to be preserved, though limited, in acidic lakes through out the Yilgarn Craton of Australia with pH less than 2 (Johnson, 2008) • Resistant biomakers. 34 Concluding Thoughts • Strong Evidence for a Habitable Climate during Noachian. – Questions about stable habitability can be answered by groundwater. • Did Life Persist for Hundreds of Years or Millions? – Is that Enough for Life to Evolve? 35 Noachian Life? 36 References • Brocks, J. J. "Archean Molecular Fossils and the Early Rise of Eukaryotes." Science285.5430 (1999): 1033-036. Print. • Catling, David. "Atmospheric Evolution of Mars." Encyclopedia of Paleoclimatology and Ancient Environments. Ed. Vivien Gornitz. Dordrecht, Netherlands: Springer, 2009. N. pag. Print. • Clifford, Stephen M., and Timothy J. Parker. "The Evolution of the Martian Hydrosphere: Implications for the Fate of a Primordial Ocean and the Current State of the Northern Plains." Icarus 154 (2001): 40-79. Print. • Farquhar, James et al. "Evidence of Atmospheric Sulphur in the Martian Regolith from Sulphur Isotopes in Meteorites." Nature 404 (2000): 50-52. Print. • Izawa, M. R. M., et al. "Basaltic Glass as a Habitat for Microbial Life: Implications for Astrobiology and Planetary Exploration." Planetary and Space Science 58 (2010): 583-91. Print. • Johnson, Sarah Stewart. Mars in the Late Noachian: Evolution of a Habitable Surface Environment. Diss. Massachusetts Institute of Technology, 2008. N.p.: n.p., n.d. Print. References Con’t • Knoll, Andrew H., Michael Carr, Benton Clark, David J. Des Marais, Jack D. Farmer, Woodward W. Fischer, John P. Grotzinger, Scott M. Mclennan, Michael Malin, Christian Schröder, Steven Squyres, Nicholas J. Tosca, and Thomas Wdowiak. "An Astrobiological Perspective on Meridiani Planum." Earth and Planetary Science Letters 240.1 (2005): 179-89. Print. • Lapen, T. J., M. Righter, A. D. Brandon, V. Debaille, B. L. Beard, J. T. Shafer, and A. H. Peslier. "A Younger Age for ALH84001 and Its Geochemical Link to Shergottite Sources in Mars." Science 328.5976 (2010): 347-51. Print. • Logan, Bruce E. et al. "Kinetics of Perchlorate- and Chlorate-Respiring Bacteria." APPLIED AND ENVIRONMENTAL MICROBIOLOGY 67.6 (2001): 2499-506. Print. • Madden, M. E. Elwood, R. J. Bodnar, and J. D. Rimstidt. "Jarosite as an Indicator of Water-limited Chemical Weathering on Mars." Nature 431.7010 (2004): 821-23. Print. • McKay, David, Everett Gibson, and Kathie Thomas-Keprta. "Possible Evidence for Life in ALH84001." Jet Propulsion Labratory (1999): 1-4. Web. • Squyres, S. W. "The Opportunity Rover's Athena Science Investigation at Meridiani Planum, Mars." Science 306.5702 (2004): 1698-703. Print. “Yet so vain is man, and so blinded by his vanity, that no writer, up to the very end of the nineteenth century, expressed any idea that intelligent life might have developed there far, or indeed at all, beyond its earthly level.” - War of the Worlds .