Lichens, cyanobacteria and molds growing in humidity of simulated Martian atmosphere: Difference between revisions
Jump to navigation
Jump to search
Lichens, cyanobacteria and molds growing in humidity of simulated Martian atmosphere (edit)
Revision as of 02:29, 23 September 2018
, 5 years agono edit summary
No edit summary |
|||
Line 1:
[[Image:Martian conditions in miniature (7494313830) (2).jpg|thumb|Martian conditions in miniature - In the Mars simulation chamber, DLR researchers recreated the atmospheric composition and pressure, the planet's surface, the temperature cycles and the solar radiation incident on the surface. The activity of polar and alpine lichen was investigated under these conditions.]]
A series of experiments by DLR (German aerospace company) in Mars simulation chambers and on the ISS show that some Earth life (Lichens and strains of chrooccocidiopsis, a green algae) can survive Mars surface conditions and photosynthesize and metabolize, slowly, in absence of any water at all. They could make use of the humidity of the Mars atmosphere.<ref name="dlrMarsStudy">[http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10081/151_read-3409/ Surviving the conditions on Mars] DLR, 26 April 2012</ref><ref name="sciencedirect.com">{{cite journal|url = http://www.sciencedirect.com/science/article/pii/S1754504812000098 | doi=10.1016/j.funeco.2012.01.008 | volume=5 | issue=4 | title=Lichens as survivors in space and on Mars | year=2012 | journal=Fungal Ecology | pages=472–479 | last1 = de Vera | first1 = Jean-Pierre}}</ref><ref name="norlx51.nordita.org">R. de la Torre Noetzel, F.J. Sanchez Inigo, E. Rabbow, G. Horneck, J. P. de Vera, L.G. Sancho [http://norlx51.nordita.org/~brandenb/astrobiology/EANA2012/single_abstracts/Delatorre.pdf Survival of lichens to simulated Mars conditions] {{webarchive|url=https://web.archive.org/web/20130603191033/http://norlx51.nordita.org/~brandenb/astrobiology/EANA2012/single_abstracts/Delatorre.pdf |date=2013-06-03 }}</ref><ref name="Issue 1 2012, Pages 102">{{cite journal|url = http://www.sciencedirect.com/science/article/pii/S0032063312002425 | doi=10.1016/j.pss.2012.08.005 | bibcode=2012P&SS...72..102S | volume=72 | issue=1 | title=The resistance of the lichen Circinaria gyrosa (nom. provis.) towards simulated Mars conditions—a model test for the survival capacity of an eukaryotic extremophile | year=2012 | journal=Planetary and Space Science | pages=102–110 | last1 = Sánchez | first1 = F.J.}}</ref><ref name="BilliViaggiu2011">{{cite journal|url=https://scholar.google.com/scholar_url?url=http://www.researchgate.net/profile/Charles_Cockell/publication/49810974_Damage_escape_and_repair_in_dried_Chroococcidiopsis_spp._from_hot_and_cold_deserts_exposed_to_simulated_space_and_martian_conditions/links/0c960530543245cde9000000.pdf&hl=en&sa=T&oi=gsb-gga&ct=res&cd=1&ei=M2AqVeLzG-fq0AG5xYGACA&scisig=AAGBfm1aHrkKehQaYpPYGQ9mjRxVTxPS0Q|last1=Billi|first1=Daniela|last2=Viaggiu|first2=Emanuela|last3=Cockell|first3=Charles S.|last4=Rabbow|first4=Elke|last5=Horneck|first5=Gerda|last6=Onofri|first6=Silvano|title=Damage Escape and Repair in DriedChroococcidiopsisspp. from Hot and Cold Deserts Exposed to Simulated Space and Martian Conditions|journal=Astrobiology|volume=11|issue=1|year=2011|pages=65–73|issn=1531-1074|doi=10.1089/ast.2009.0430|pmid=21294638|bibcode=2011AsBio..11...65B}}</ref> Though the absolute humidity is low, the relative humidity at night reaches
==Humidity observations of the Mars atmosphere by Curiosity==▼
[[Image:Curiosity humidity measurements.gif|thumb|Upper chart shows the humidity, lower chart shows the volume mixing ratio in parts per million, both measurements taken at the same time, height 1.6 meters above the ground]][[Image:Curiosity temperature measurements.gif|thumb|Upper chart shows the average temperature, lower chart shows the range, the warm orange and red colours are Curiosity annual readings, the blue and green dcolours are for the Viking landers and the gray colours are for the Phoenix lander]]▼
This section is based on the survey article by Martinez et al, "The modern near-surface martian climate: A review of in-situ meteorological data from Viking to Curiosity."<ref>Martínez, G. M., C. N. Newman, A. De Vicente-Retortillo, E. Fischer, N. O. Renno, M. I. Richardson, A. G. Fairén et al. "The modern near-surface martian climate: A review of in-situ meteorological data from Viking to Curiosity." Space Science Reviews 212, no. 1-2 (2017): 295-338.</ref>▼
The humidity variations on Mars are mainly due to the daily and seasonal variations of temperature of the air. Colder air has a higher relative humidity for the same water content.▼
The amount of water vapour can be measured as the volume mixing ratio of water vapour (VMR). This varies between around 10 ppm in winter and 70 ppm in summer at the Curiosity site. You might expect the highest relative humidithy then to be in summer, but no, it's in winter, because it is so much colder then. The summer relative himidity is about 10% and the winter relative humidity around 70%.▼
So, it's 10ppm (approx) for 70% RH in winter, and 70 ppm for 10% RH in summer (by a strange coincidence the numbers are reversed).▼
Curiosity has measured relative humidity readings of up to 70% in winter, measured at a height of 1.6 meters above ground level (see Sect 14<ref>[https://link.springer.com/article/10.1007/s11214-017-0360-x#Sec14 Sec 14]</ref>. This is in winter with a temperature range of around 50 C and mean temperature around -63 C, so lowest temperature around -88 C (see their figure 5<ref>[https://link.springer.com/article/10.1007/s11214-017-0360-x#Fig5 Fig5]</ref>), and the highest humidity is normally reached between 04:00 and 06:00 Local Mean Solar Time (LMST).. The lowest humidity readings are between 10:00 and 18:000 LMST, when they are typically less than 5%▼
Curiosity hasn't directly observed the frosts that Viking observed at somewhat higher latitudes. But there is indirect evidence that frosts may form at times.▼
==Lichens relying on 75% night time humidity==
Line 91 ⟶ 75:
{{quote|The work presented here and work conducted in deserts around the world in the past 40 years, indicate that any putative microbial life on Mars would have likely colonized the insides of rocks and crusts, as they provide natural shelter against harmful radiation and also enhance the moisture conditions on a micro scale. Sulfate and chloride evaporitic deposits have been suggested as a possible oasis for an extant biota, or the last refuge for an extinct biota on the surface of Mars). In this context, terrestrial evaporite rocks, including the Ca-sulfate crusts of the dry core of the Atacama Desert as key terrestrial analogs of Martian aqueous deposits, might prove useful for assessing the habitability of the Martian surface, and develop or improve current strategies for the search for life on Mars}}
▲==Humidity observations of the Mars atmosphere by Curiosity==
▲[[Image:Curiosity humidity measurements.gif|thumb|Upper chart shows the humidity, lower chart shows the volume mixing ratio in parts per million, both measurements taken at the same time, height 1.6 meters above the ground]][[Image:Curiosity temperature measurements.gif|thumb|Upper chart shows the average temperature, lower chart shows the range, the warm orange and red colours are Curiosity annual readings, the blue and green dcolours are for the Viking landers and the gray colours are for the Phoenix lander]]
▲This section is based on the survey article by Martinez et al, "The modern near-surface martian climate: A review of in-situ meteorological data from Viking to Curiosity."<ref>Martínez, G. M., C. N. Newman, A. De Vicente-Retortillo, E. Fischer, N. O. Renno, M. I. Richardson, A. G. Fairén et al. "The modern near-surface martian climate: A review of in-situ meteorological data from Viking to Curiosity." Space Science Reviews 212, no. 1-2 (2017): 295-338.</ref>
▲The humidity variations on Mars are mainly due to the daily and seasonal variations of temperature of the air. Colder air has a higher relative humidity for the same water content.
▲The amount of water vapour can be measured as the volume mixing ratio of water vapour (VMR). This varies between around 10 ppm in winter and 70 ppm in summer at the Curiosity site. You might expect the highest relative humidithy then to be in summer, but no, it's in winter, because it is so much colder then. The summer relative himidity is about 10% and the winter relative humidity around 70%.
▲So, it's 10ppm (approx) for 70% RH in winter, and 70 ppm for 10% RH in summer (by a strange coincidence the numbers are reversed).
▲Curiosity has measured relative humidity readings of up to 70% in winter, measured at a height of 1.6 meters above ground level (see Sect 14<ref>[https://link.springer.com/article/10.1007/s11214-017-0360-x#Sec14 Sec 14]</ref>. This is in winter with a temperature range of around 50 C and mean temperature around -63 C, so lowest temperature around -88 C (see their figure 5<ref>[https://link.springer.com/article/10.1007/s11214-017-0360-x#Fig5 Fig5]</ref>), and the highest humidity is normally reached between 04:00 and 06:00 Local Mean Solar Time (LMST).. The lowest humidity readings are between 10:00 and 18:000 LMST, when they are typically less than 5%
▲Curiosity hasn't directly observed the frosts that Viking observed at somewhat higher latitudes. But there is indirect evidence that frosts may form at times.
This article uses some text developed for Touch Mars?<ref>[http://robertinventor.com/booklets/If_humans_touch_Mars.htm#salt_pillar_oases Touch Mars? Salt pillar oases] - Touch Mars? by Robert Walker</ref>.
| |||
