Mars: Life, Subglacial Oceans, Abiogenic Photosynthesis, Seasonal Increases and Replenishment of Atmospheric Oxygen

Baltic astronomy

article

Rhawn G. Joseph¹  Natalia S. Duxbury²  Giora J. Kidron³  Carl H. Gibson⁴  Rudolph Schild⁶ 

[1] Astrobiology Research Center;George Mason University;Institute of Earth Sciences, The Hebrew University of Jerusalem;Scripps Center for Astrophysics and Space Sciences;Dept. Aerospace Engineering, University of California;Harvard-Smithsonian Center for Astrophysics (Emeritus)

关键词: Mars;    Water;    Oxygen;    Oceans;    Algae;    Cyanobacteria;    Atmosphere;    Lichens;    Life on Mars;   

DOI  :  10.1515/astro-2020-0020

来源: Institute of Theoretical Physics and Astronomy

【 摘 要 】

The discovery and subsequent investigations of atmospheric oxygen on Mars are reviewed. Free oxygen is a biomarker produced by photosynthesizing organisms. Oxygen is reactive and on Mars may be destroyed in 10 years and is continually replenished. Diurnal and spring/summer increases in oxygen have been documented, and these variations parallel biologically induced fluctuations on Earth. Data from the Viking biological experiments also support active biology, though these results have been disputed. Although there is no conclusive proof of current or past life on Mars, organic matter has been detected and specimens resembling green algae / cyanobacteria, lichens, stromatolites, and open apertures and fenestrae for the venting of oxygen produced via photosynthesis have been observed. These life-like specimens include thousands of lichen-mushroom-shaped structures with thin stems, attached to rocks, topped by bulbous caps, and oriented skyward similar to photosynthesizing organisms. If these specimens are living, fossilized or abiogenic is unknown. If biological, they may be producing and replenishing atmospheric oxygen. Abiogenic processes might also contribute to oxygenation via sublimation and seasonal melting of subglacial water-ice deposits coupled with UV splitting of water molecules; a process of abiogenic photosynthesis that could have significantly depleted oceans of water and subsurface ice over the last 4.5 billion years.

【 授权许可】

Unknown