User:Robertinventor/possibility of Mars having enough water to support life
Made a copy of the last version of this section before it was deleted from Water on Mars. Though slightly out of date now, it has much useful material in it and many useful links. I only added a couple of sentences to this, most of which was written by other editors.
- 1 Recommendation, new article on the Present-Day Habitability of Mars
- 2 More about the suggestion
- 3 Additional references for the proposed page
- 4 Possibility of Mars having enough water to support life
- 5 Some useful quotes
- 6 Why I am not going to attempt an article on this right now
- 7 Why Battery Included's article is OR and no longer valid
Recommendation, new article on the Present-Day Habitability of Mars[edit source | hide | hide all]
I highly recommend that Wikipedia should have an article on this subject.
This is the conference on the subject "The Present-Day Habitability of Mars 2013".
There are many papers on it every year by researchers in the US, UK, and Germany, and including scientists from JPL, DLR in Germany, and the NASA Ames Research Center. It has been a major subject in the literature since 2008 and undoubtedly passes WP:NOTABLE.
Paige is planning to create a new journal solely devoted to this subject. See UCLA holds Mars habitability conference:
At the end of the conference, Paige said he intends to publish a special journal focusing on the present-day habitability of Mars and hopes to reconvene the conference within the next five years
If another editor feels as strongly as I do that creation of this new page is a good idea, please let me know via my talk page. With two main editors involved in its creation, it might be able to survive AfD and edit warring. But be aware, there are two editors who are passionately opposed to creation of this article.
More about the suggestion[edit source | hide]
It would cover all present day habitability suggestions so including deep below the surface, but the main focus would be on surface habitability because recent research in the last five or six years focuses on surface habitability far more than deep down habitability. For completeness and context, would also briefly cover possible habitats with liquid brines that are not thought to be habitable (e.g. because monolayers or because too cold), and the possiblity of uninhabited habitats But main focus on suggested habitable habitats.
It could describe all the biocidal and bioinhibitory factors in the 14 point list, and so mention cosmic radiation as the tenth in the list, in its appropriate place as a bioinhibitory factor. But unlike the Life on Mars page, it would not put cosmic radiation as top of the list because that is out of date research for habitable surface environments.
Habitats to cover include
- Lichen on the surface and cyanobacteria endoliths, both of which have remarkable UV resistance.
- Deliquescing salts that may in special conditions create thin layers of liquid brine a few mm thick, just below the surface and habitable for a few hours each day.
- Slightly deeper deliquescing salt habitats below permafrost layer down to about half a meter deep - with special mixtures of salts - extremely cold - are they warm enough for life?
- water droplets may form around grains of dust embedded in snow (so prevented from evaporation by the snow)
- a thin possibly habitable water may melt beneath the dry ice covering in winter, N. pole.
- The advancing bioreactor sand dunes idea.
- Possible habitat at base of ice sheets
- Possibliity of occasional impacts that melt the polar ice caps and form lakes with a covering of ice that remain liquid for thousands of years before they cool down.
- deep habitats that are isolated from the surface by impermeable layers - either geothermal heat sources - or deep enough to use thermal heat from Mars itself.
- Temporary intermittent flows of brine or other liquids may form the linear features on some slopes on Mars.
- Deep ice sheets in equatorial regions that may move towards the surface by process of sublimation giving a remote possibility of a habitable sub soil layer even in equatorial regions (not that likely perhaps but is mentioned in the literature).
In a separate article could go into this level of detail.
I have written a post for science20.com on this subject, which can give an idea of what it could involve, of course leaving out the earlier history of ideas about life on Mars which is already adequately covered here:
It would be like that except encyclopedic rather than journalistic in tone with citations etc. for every significant statement.
It would be based on the section "Possibility of Mars having enough water to support life" see below, which got deleted from Water on Mars. I feel there is enough for a separate article and the Water on Mars and Life on Mars pages could summarize it briefly.
Please see though, User:Robertinventor/Present_day_habitability_of_Mars_dispute - if that was taken to dispute resolution and BatteryIncluded's claim was upheld presumably material on the habitability of the surface of Mars couldn't be included.
Additional references for the proposed page[edit source | hide]
Possibility of Mars having enough water to support life[edit source | hide]
Life is generally understood to require liquid water. Some evidence suggests that Mars had enough water to form lakes and to carve huge river valleys. Vast quantities of water have been discovered frozen beneath much of the Martian surface. Nevertheless, many significant issues remain.
- History. When did the water once flow on Mars? Mars areas have been extremely dry for long periods, as marked by the presence of olivine that would be decomposed by water. On the other hand, many other areas contain clay and/or sulfates, which indicate the presence of liquid water on the surface.
- Sulfates. While the presence of sulfates bolsters the case for surface water, they present problems of their own. Sulfates form under acid conditions. On Earth some organisms can survive in acidic environment, but questions remain about the possibility of life forming under such conditions. Even allowing for adaptation to acidic environments, could life actually originate in acidic waters? On the other hand, carbonates, which do not form in acid solutions, have been found in Martian meteorites by the Phoenix lander and by the Compact Reconnaissance Imaging Spectrometer, an instrument aboard the NASA Mars Reconnaissance Orbiter.
- Salts. The saltiness of the soil could be a major obstacle for life. Salt has been used by the human race as a major preservative since most organisms can not live in highly salted water (halophile bacteria being an exception).
- Oxidizers. The Phoenix mission discovered perchlorate, a highly oxidizing chemical in the soil. Although some organisms use perchlorate, the chemical could be hostile to life. Other research show that there is a variety of soil types on Mars including clays and alkaline soil as well as acidic soil, and studies of Mars analog soils find that they are not unusually or severely biotoxic, and not growth limiting for Mars microbiota (if present).
Benton Clark III, a member of the Mars Exploration Rover (MER) team, surmises that Martian organisms could be adapted to a sort of suspended animation for millions of years. Indeed, some organisms can endure extreme environments for a time. Measurements performed on Earth under 50 meters of permafrost, showed that half of the microorganisms would accumulate enough radiation from radioactive decay in rocks to die in 10 million years, but if organisms come back to life every few million years they could repair themselves and reset any damaged systems, especially DNA. Other scientists are in agreement.
The discovery of organisms living in extreme conditions on Earth has brought renewed hope that life exists, or once existed on Mars. Colonies of microbes have been found beneath almost 3 kilometers of glaciers in the Canadian Arctic and in Antarctica. Could microbes live under the ice caps of Mars? In the 1980s, it was thought that microorganisms might live up to a depth of a few meters under ground. Today, we know that a wide variety of organisms grow to a depth of over a mile. Some live on gases like methane, hydrogen, and hydrogen sulfide that originate from volcanic activity. Mars has had widespread volcanic activity. It is entirely possible that life exists near volcanoes or underground reservoirs of hot magma. Some organisms live inside of basalt (the most common rock on Mars) and produce methane. Methane has been tracked on Mars. Some[who?] believe there must be some (possibly biological) mechanism that is producing methane since it will not last long in the present atmosphere of Mars. Other organisms eat sulfur compounds; the same chemicals that have been found in many regions of Mars. Scientists have suggested that whole communities of organisms could thrive near areas heated by volcanic activity. Studies have shown that certain forms of life have adapted to extremely high temperatures (80° to 110 °C). With all the volcanic activity on Mars, one would suppose that certain places have not yet cooled down. An underground magma chamber might melt ice, then circulate water through the ground. Remains of hot springs like the ones in Yellowstone National Park have actually been spotted by the Mars Reconnaissance Orbiter. Minerals associated with hot springs, such as opal and silica have been studied on the ground by Spirit Rover and mapped from orbit by the Mars Reconnaissance Orbiter. Some volcanoes, like Olympus Mons, seem relatively young to the eyes of a geologist. However, no warm areas have ever been found on the surface. The Mars Global Surveyor scanned most of the surface in infrared with its TES instrument. The Mars Odyssey's THEMIS, also imaged the surface in wavelengths that measure temperature.
The possibility of liquid water on Mars has been examined. Although water would quickly boil or evaporate away, lake-sized bodies of water would quickly be covered with an ice layer which would greatly reduce evaporation. With a cover of dust and other debris, water under ice might last for some time and could even flow to significant distances as ice-covered rivers. Lake Vostok in Antarctica may have implications for liquid water still being on Mars because if the lake existed before the perennial glaciation began, is likely that the lake did not freeze all the way to the bottom. Accordingly if water existed before the polar ice caps on Mars, it is likely that there is still liquid water below the ice caps. Large quantities of water could be released, even today, by an asteroid impact. It has been suggested that life has survived over millions of years by periodic impacts which melted ice and allowed organisms to come out of dormancy and live for a few thousands of years. But if impacts brought the water, maybe liquid water did not exist on the surface very long. Large river valleys could have been made in short periods of time (maybe just days) when impacts caused water to flow as a giant flood. We suppose that Mars had great amounts of water because of the existence of so many large river valleys. Maybe, valleys did not take thousands to millions of years to form as on the Earth. It is accepted that a vast network of channels, resembling many Martian channels, were formed in a very short time period in eastern Washington State when floods were caused by a breakout of an ice-dammed lake. So, perhaps not that much water was involved and maybe it did not last long enough for life to develop.
Studies have shown that various salts present in the Martian soil could act as a kind of antifreeze—keeping water liquid well below its normal freezing point. Some calculations suggest that tiny amounts of liquid water may be present for short periods of time (hours) in some locations. Some researchers have calculated that when taking into consideration insolation and pressure factors that liquid water could exist in some areas for about 10% of the Martian year; others estimate that water could be a liquid for only 2% of the year. Either way, that may be enough liquid water to support some forms of hardy organisms. It may not take much liquid water for life; organisms have been found on Earth living on extremely thin layers of unfrozen water in below-freezing locations. Research described in December 2009, showed that liquid water could form in the daytime inside of snow on Mars. As light heats ice, it may be warming up dust grains located inside. These grains would then store heat and form water by melting some of the ice. The process has been already been observed in Antarctica. Enough water may be produced for physical, chemical, and biological processes..
Another location under consideration is in underground caves on Mars. There is some evidence for possible subsurface ice sheets near the equator. This may for instance be geologically ancient ice which may melt or sublimate on its way towards the surface.
Experiments also suggest that lichen and bacteria may also be able to survive solely on humidity from the air, particularly in cracks in the rocks.  The water is present in the morning and evening when humidity briefly condenses as precipitation across the surface, and the organisms can absorb it.
Some useful quotes[edit source | hide]
Some of these may be relevant for the article.
Evidence is building that liquid water might flow seasonally at some Martian sites, potentially providing a haven for life as we know it "We certainly can't rule out the possibility that it's habitable today," said Alfred McEwen of the University of Arizona, principal investigator for the HiRise camera aboard NASA's Mars Reconnaissance Orbiter spacecraft.
... Martian life may be able to survive even in places where water doesn't seep and flow, some scientists stressed.
... "Perchlorate, it turns out, is a potent chemoautotrophic energy source," said Carol Stoker, also of NASA Ames, noting that the chemical could potentially sustain microbes in the dark Martian subsurface, where photosynthesis is not an option.
And some Earth microbes use perchlorate for food, so that could be happening on Mars as well, scientists have pointed out.
... "The Present-Day Habitability of Mars" took place Feb. 4-5 and was co-hosted by the NASA Astrobiology institute and the UK Centre for Astrobiology.
"Yeah it's a big deal," said Robert Zubrin, president and founder of the Mars Society. "The idea that there's liquid water on Mars today at the surface means that there could be life on Mars today at the surface."
Presentation after surveying habitability of the Phoenix landing site, at 12.07 into it, she says
"Furthermore the site appears to be habitable in modern times. I assert that signatures of modern life are more likely to be found than signatures of life deposited millions of years ago"
Here is a paper from 2012 that surveys the water question again from Space Science, September 2012 Water and Brines on Mars: Current Evidence and Implications for MSL] It is particularly focused on the Curiosity landing site which is an unlikely location for brines because so close to the equator. But they survey other areas concluding polar regions as most likely and say
"There is no question that theoretically liquid brines can form at the surface and in the shallow and deep subsurface of Mars, even in the present climate. Indeed, liquid brines can form by deliquescence at the surface and in the shallow subsurface (≤1 m). At the shallow subsurface it can also form by direct contact of salts with physisorbed water and melt water. In the deep subsurface (≥100 m) it can form by direct contact of salts with aquifers."
- Here is a habitability assessment for the Phoenix landing site published February of this year: Assessing Habitability: Lessons from the Phoenix Mission
"During high obliquity periods, temperatures allowing metabolism extend nearly a meter into the subsurface. Phoenix discovered ~1%w/w perchlorate salt in the soil, a chemical energy source utilized by a wide range of microbes. Nutrient sources including C, H, N, O, P and S compounds are supplied by known atmospheric sources or global dust. Environmental conditions are within growth tolerance for terrestrial microbes. Summer daytime temperatures are sufficient for metabolic activity, the pH is 7.8 and is well buffered and the projected water activity of a wet soil will allow growth. In summary, martian permafrost in the north polar region is a viable location for modern life. Stoker et al. presented a formalism for comparing the habitability of various regions visited to date on Mars that involved computing a habitability probability, defined as the product of probabilities for the presence of liquid water (P(wsub l)), energy (P(sub e)), nutrients (P(sub ch)), and a benign environment (P(sub b)). Using this formalism, they argued that the Phoenix site was the most habitable of any site visited to date by landed missions and warranted a follow up mission to search for modern evidence of life."
BTW there is a bit of confusion sometimes as there is another phenomenon, monolayers of liquid water just one molecule thick that may occur on Mars. Those seem unlikely to be a habitat for life, or at any rate very challenging. But these are not monolayers.
- This is another one, this time it's about advancing sand dunes, a new habitat I haven't seen mentioned before: HABITABILITY OF TRANGRESSING MARS DUNES
"Advancing martian dunes mix oxidants, reductants, water, nutrients, and possibly organic
carbon in what could be considered bioreactors. Thus, martian dunes function as small scale analogues of the global geological cycles that are important in maintaining Earth's habitabiliy. On Mars, carbon can be cycled from the surface of the dune to its subsurface where it may come in contact with moisture and oxidants. Compounds oxidized at the surface of dunes by UV radiation and oxygen are buried on the lee side of dunes and mixed with reductants, carbon, and ephemeral brines. In addition, reduced compounds will be exposed at the surface on the windward side of dunes where they can be oxidized and complete the cycle. Other global cycles on Mars are likely to be driven by rising and sinking fluids in the subsurface ; however, transgressing dunes are a recyclable potential habitat readily accessible by the Mars Science Laboratory. Additional measurements by MSL such as detecting organic carbon and reduced nitrogen compounds would support the hypothesis that moving dunes are potential microbial habitats. The absence of these compounds would indicate that the today's dunes are unlikely to be habitable."
- This is a recent paper that studies brines formed in similar conditions in Antarctica, obviously not exactly the same but relevant: Don Juan Pond, Antarctica: Near-surface CaCl2-brine feeding Earth's most saline lake and implications for Mars]
"Don Juan Pond (DJP), found at the lowest point in the South Fork of Upper Wright Valley, Antarctica (Figure 1a), is the most saline natural body of water in the world1. As a consequence, it rarely freezes, even when the surface temperature descends to −50°C during Austral winter and it is a unique site for the study of habitability in extreme environments on Earth, and potentially for life on Mars
"While the volumes of freshwater available to these hydrologic systems on Mars is unknown, recent work in the Atacama desert has provided in-situ documentation of cyanobacteria that are capable of subsisting entirely on the brines created from deliquescence in halite rocks34, a very localized ecological model that has been proposed for Mars in the past35. Furthermore, work in the MDV has shown that certain organisms are capable of being preserved in a cryptobiotic state for decades, then flourish once exposed to stream waters36. Thus, if RSL and chloride-bearing basin floor units on Mars do represent DJP-like hydrologic systems, they may have significant potential for hosting resilient microbiota, and the most habitable places on Mars may mimic the least habitable places on Earth."
Analysis of seasonally frost-covered Martian dunes and terrestrial extremophiles in cryptobiotic crust revealed that circumpolar dark dunes on Mars form an ideal habitat for hypothetic photosynthesizing organisms on the planet. In springtime, the dark basaltic dunes show ephemeral seepage-like features on their surface, which (based on theoretical calculations) may be the result of interfacial water or bulk brine-related movement. Such a thin water film may also decompose the aggressive oxidants there. Temperature values in spring around noon could be favorable for metabolism of known extremophiles on Earth. During this warming period, the water loss could be reduced by densely packed grain structure of the soil, hygroscopic salts, and the embedding polysaccharide-like materials, as it was observed in the samples of cryptobiotic crust from hot and cold deserts on Earth. The best periods for H2O uptake are the nighttime hours.
Terrestrial cyanobacteria living 2–4 mm below the rock surface in the so-called cryptobiotic crust demonstrate possible analogous strategies for survival in the Martian environment. On Mars, even a thin grain layer coverage decreases water loss rate and screens UV radiation. The organisms we collected in hot and cold deserts on Earth showed examples for survival strategies like seasonal movement, task sharing in UV screening, and a special method called optical fiber strategy (whereby organisms conduct light to the deeper subsurface). The terrestrial observation of recovery of cyanobacteria in minutes after wetting also supports the supposed long dormant-short active life cycle of hypothetical organisms on Mars. The circumpolar region on Mars has been found to be one of the best possible habitats today, because water ice and springtime-elevated temperature are both present there. These dark dunes are less oxidized than the average Martian surface, and their grain structure enhances the trapping of volatiles, while their dark color helps the fast warming in daytime.
- This is also relevant: Hygroscopic Salts and the Potential for Life on Mars]
The deliquescence of sodium chloride results in transient solutions with aw compatible with growth of terrestrial microorganisms down to 252 K, whereas for calcium chloride and magnesium chloride it results in solutions with aw below the known limits for growth at all temperatures. However, taking the limits of aw used to define special regions on Mars, the deliquescence of calcium chloride deposits would allow for the propagation of terrestrial microorganisms at temperatures between 265 and 253 K, and for metabolic activity (no growth) at temperatures between 253 and 233
Also this 2012 thesis looks at alkalitolerant strains that are found in soda lakes on Earth and are also common in clean rooms. Raises concern that spacecraft to Mars could transfer these to habitable environments on Mars and so contaminate the planet/ An astrobiological study of an alkaline-saline hydrothermal environment, relevant to understanding the habitability of Mars see 8.5. Relevance of alkaline/saline analogue studies to the contamination of Mars abstarct here
The culture based study of the
Phoenix spacecraft clean-room demonstrated that alkalitolerant strains (such as Bacillus pumilus and Oceanobacillus iheyensis) were present and were not a minor part of the cultured community, being frequently detected (Ghosh et al., 2010). This indicates that these alkalitolerant organisms have survived the sterilisation procedure applied, and there is no reason why the strains could not also be present on the space craft itself. If this is the case, and the organisms were shielded during the flight to Mars, then theoretically they could be transferred to the surface/subsurface of the planet. This would have implications for the discovery of life on Mars.
These organisms would not necessarily be strictly defined as extremophiles, but are tolerant of extreme conditions such as pH. Together with the fact that alkalitolerant isolates from Lake Magadi could survive desiccation, oxidative atmosphere and low temperatures, as long as they are provided with some protection from UV-C irradiation (and ionizing radiation), makes the potential contamination of Mars with alkalitolerant organisms a real consideration. The additional tolerance of these organisms to high salinity and temperatures makes them resistant to a wider range of environmental stresses.
- This looks like an interesting recent survey paper (2013), but unfortunately can only find an abstract for it: Metabolic Activity of microorganisms during and after simulated Mars-like conditions – what do we learn about the habitability of the Red Planet?. It is from a conference from February of this year, I wonder if that just means it hasn't been published yet?
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Why I am not going to attempt an article on this right now[edit source | hide]
BatteryIncluded has deleted this section from the Water on Mars page. He also archived the entire talk page with the section where I suggest creation of this article. In view of his actions I am sure he would recommend an AfD for any article on the subject and I don't have the energy to attempt to save it. I am sure that Warren Platts would also come in vigorously in his support and with two such passionate editors with very similar views totally opposed to its creation, and hardly anyone on wikipedia currently strongly in support of my case, I think it would be deleted just like my article User:Robertinventor/Concerns for an early Mars sample return backup.
I believe that these two editors would also engage in continual edit warring on the article if I create it by myself, and I discovered recently how vulnerable a single editor creator of a wikipedia article can be to edit warring.
If another editor feels as strongly as I do that creation of this new page is a good idea please let me know. I would gladly help in a collaboration and with two editors versus two in the debate, feel it would surely survive an AfD. If either of these editors attempted an edit war they would be stopped easily.
The reason I was so vulnerable to Warren Platts edit warring for User:Robertinventor/Concerns for an early Mars sample return backup is because I was the only editor involved in its creation. Robert Walker (talk) 06:27, 27 June 2013 (UTC)
Why Battery Included's article is OR and no longer valid[edit source | hide]
BatteryIncluded's argument that the surface of Mars is uninhabitable, as presented in the Water on Mars#Habitability assessment page has not been seen in the literature since the Phoenix intriguing potential leg droplet observations of 2008. It only applies to dormant life. On the surface, life is subject to cosmic radiation levels equivelent to the interior of the ISS. It is not survivable in dormant states for geological timescales, but is easily survivable by radiodurans and other micro-organisms for a considerable number of years (probably millennia at least, I would imagine). Almost all micro-organisms can survive it in dormant states for shorter periods.
In this paper which he cites in the article, cosmic radiation was specifically excluded from the list of biocidal factors to be considered: (see [http://plantpath.ifas.ufl.edu/faculty/statewide/schuerger/Schuerger_2012_PSS-3371.pdf Biotoxicity of Mars soils: 1. Dry deposition of analog soils on microbial colonies and survival under Martian conditions])
The 14 point list is given in order of importance, so it is 10th in importance of conditions impacting on habitability of the surface of Mars. See the video presentation from Feb 2013 by Growth and Ultrastructure of Bacteria in 7 mbar, 0° C, and CO2-enriched Anoxic Atmospheres: Implications for the Forward Contamination of Mars by Andrew C. Schuerger, one of the authors of the paper BatteryIncluded cites to support his view.
Solar particle events and galactic cosmic rays were considered external factors that occur infrequently or at low dosage, respectively.