Lichens, cyanobacteria and molds growing in humidity of simulated Martian atmosphere: Difference between revisions
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Lichens, cyanobacteria and molds growing in humidity of simulated Martian atmosphere (edit)
Revision as of 14:15, 25 March 2019
, 5 years ago→Lichens relying on 75% night time humidity to metabolize, photosynthesize, and develop new growth
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[[Image:Pleopsidium chlorophanum in Antarctica.jpg |thumb|[[Pleopsidium chlorophanum]] on granite, collected at an altitude of 1492 m above sea level at "Black Ridge" in North Victoria Land, Antarctica. This photograph shows its semi-endolithic growth in Antarctic conditions. You can see that it has fragmented the granite, and that pieces of the granite are partly covering it, possibly helping to protect from UV light. Photograph credit DLR]]
[[Image:Pleopsidium chlorophanum.jpg|thumb|The same lichen showing its spreading habit in more usual conditions]]
Another study in 2014 by German aerospace DLR in a Mars simulation chamber used the lichen [[Pleopsidium chlorophanum]]. This lives in the most Mars like environmental conditions on Earth, at up to 2000 meters in Antarctica. It is able to cope with high UV, low temperatures and dryness. It is mainly found in cracks, where just a small amount of scattered light reaches it. This is probably adaptive behaviour to protect it from UV light and desiccation. It remains metabolically active in temperatures down to -20 C, and can absorb small amounts of liquid water from the atmosphere in an environment
As measured in Antarctica, the relative humidity in the lichen's niche microhabitat varies from 57% to 79% as the temperature varies from -6 °C to -8
In this experiment the temperature varied between +21 °C and -50 °C. Relative humidity is higher in cold air, for the same concentrations of water vapour, and as the temperature varied, the relative humidity varied between 0.1% and 75%. The atmosphere consisted of 5% CO<sub>2</sub>,4%N<sub>2</sub>, and 1% O<sub>2</sub> at 800 Pa or about 0.79% of Earth's sea level atmospheric pressure. This approximates conditions that are encountered in the equatorial and lower lattitude regions of Mars. <ref name="DLRLichenHabitable"/>
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