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User:Robertinventor/Simple animals could live in Martian brines - Extended Interview with planetary scientist Vlada Stamenković: Difference between revisions

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User:Robertinventor/Simple animals could live in Martian brines - Extended Interview with planetary scientist Vlada Stamenković (edit)

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<!-- details of atmosphere of Mars in http://science.sciencemag.org/content/341/6143/263 -->
[[File:Vlada Stamenković.jpg|thumb|left|Dr. Vlada Stamenković - planetary scientist at JPL and lead author of the paper. Wikinews interviewed him about the new Mars research via email.]]
The {{w|Atmosphere of Mars|atmosphere of Mars}} is far too thin for us to breathe, or indeed, for lungs like ours to extract oxygen at all. It has around 0.6% of the pressure of Earth's atmosphere, on average,. This is mainly carbon dioxide; only 0.146% of that is oxygen. Yet the result of their modeling was clear. In the cold conditions on Mars these minute amounts of oxygen can get into the salty seeps of water which may be present there. What's more, the oxygen levels anywhere on Mars could reach the levels needed to support any microbial life that depends on oxygen.
 
Some organisms can survive without oxygenit, but oxygen permits a more energy-intensive metabolism. Almost all complex multicellular life on Earth depends on oxygen. TheThey colderfound that cold water is,would thetake up much more oxygen itthan canwarm take upwater. In the coldest salty water atin the polespolar regions, covering perhaps 6.5% of the Martian surface, the oxygen levels on Mars may be enoughget evenhigh enough for simple animals such as sponges.
 
As interviewed by Wikinews:
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::'''Vlada Stamenković''': We were absolutely flabbergasted. I went back to recalculate everything like five different times to make sure it's a real thing.
 
[[File:Warm Season Flows on Slope in Newton Crater (animated-cropped).gif|thumb|Seasonal changes in recurrent slope lineae on a steep slope in Newton Crater at 41.6 degrees south latitude on Mars. These long narrow dark streaks form on sun facing slopes when surface temperatures approach the melting point of ice. They extend in spring, broaden through the summer, and fade in autumn. Some water is involved as shown by the presence of hydrated salts, though there is debate about how much is due to water and how much to other processes such as dust flows. OneThis is one of theour best current candidates for possibly habitable salty water on [[Mars]].]]
 
Some background may help before we get to the main interview with Vlada Stamenković.
 
'''''(background information):''''' You might wonder why they would researchfocus intotheir theseresearch coldon salty solutions. What about fresh water? Well,It's freshbecause waterit is likely to be rare on present day Mars,. usuallyUsually the air pressure is so low that fresh water is not stable even at just above freezing, at 0&nbsp;°C. TheMars does have a higher pressure atmosphere at its lowest points such as the depths of the huge ancient impact crater of the {{w|Hellas Planitia|Hellas basin}}, doand this does raise the boiling point of fresh water to 10&nbsp;°C,. butHowever, that still means that it is close to boiling point already at 0&nbsp;°C. If any ice melts, the water would evaporate away rapidly, indeed the pressure is so low that ice also isn't stable either at that temperature. <!--see Making a Splash on Mars-->
 
However, salty brines can be liquid at well below 0&nbsp;°C, for the same reason salt helps keep roads ice free. TheseSalts, lowand temperaturesvery alsosalty turnbrines outcounteract the tendency of the water to beevaporate idealat forlow takingpressures. upThey oxygencan also take in water from the atmosphere too, in the process known as deliquescence, and are especially good at doing this at low temperatures.
 
Curiosity discovered indirect evidence of this processdeliquescence in the equatorial regions (through humidity measurements). ItThese isregions are so dry that there isn't even any ice therein the surface soil, yet it found that brines form during winter nights in the top 15cm of the soil through {{w|Hygroscopy#Deliquescence|deliquescence}}. They take up water from the atmosphere at night when the salts reach temperatures of around -70&nbsp;°C. This water then evaporates again as the soil warms up through the day, and the process repeats every day - night cycle. <!-- "Evidence of liquid water found on Mars" in background information -->▼
Salts, and very salty brines counteracting the tendency of the water to evaporate at low pressures, and can take in water from the atmosphere too, in the process known as deliquescence. They are especially good at doing this at low temperatures.
 
There is indirect evidence for other salty brines on Mars, perhaps more habitable than the Curiosity brines. In their paper, Stamenković et al. mention the hydrated magnesium and calcium salts associated with the Recurring Slope Lineae. These seasonal streaks form in spring on sun facing slopes, extend and broaden through the summer and fade away in autumn. The streaks themselves are not damp patches, but they may be associated with thin seeps of brine just below the surface. Later research suggests dust flows may also be involved. However the hydrated perchlorate salts observation still has to be explained, as well as the seasonal timing, not correlated with the winds. It'sThis is considered to be good evidence that there is at least an element of seasonal hydration associated with the streaks. The literature on this topic has a vigorous dialog between researchers who favour greater or lesser elements of brines in this process.▼
▲Curiosity discovered indirect evidence of this process in the equatorial regions (through humidity measurements). It is so dry that there isn't even any ice there, yet it found that brines form during winter nights in the top 15cm of the soil through {{w|Hygroscopy#Deliquescence|deliquescence}}. They take up water from the atmosphere at night when the salts reach temperatures of around -70&nbsp;°C. This water then evaporates again as the soil warms up through the day, and the process repeats every day - night cycle. <!-- "Evidence of liquid water found on Mars" in background information -->
 
Before these new results, scientists assumed any present day Martian life would be able to grow without oxygen. There are several possibilities for this, based on Mars simulation experiments. Martian life could include certain blue-green algae such as {{w|Chroococcidiopsis#Mars colonization|chroococcidiopsis}}, some black fungi, and some purple salt loving {{w|Haloarchaea#As exophiles|haloarchaea}} found in salt ponds and hypersaline lakes on Earth. <!--for the black fungi, Zakharova et al paper in background information-->. Some lichens such as {{w|Pleopsidium chlorophanum}} also have some potential for surviving in Mars surface conditions without oxygen. They can do this because the algal component is able to make the oxygen needed by its fungal component. [[Image:Martian conditions in miniature (7494313830) (2).jpg|thumb|Experiments by DLR (German aerospace company) in Mars simulation chambers and on the ISS show that some lichens such as {{w|Pleopsidium chlorophanum}} can survive Mars surface conditions and photosynthesize and metabolize, slowly, using only the humidity of the Mars atmosphere. The algal component provides oxygen for the fungal component, giving a way for multicellular life to survive without any oxgyen on Mars]]▼
▲There is indirect evidence for other salty brines on Mars, perhaps more habitable than the Curiosity brines. In their paper, Stamenković et al. mention the hydrated magnesium and calcium salts associated with the Recurring Slope Lineae. These seasonal streaks form in spring on sun facing slopes, extend and broaden through the summer and fade away in autumn. The streaks themselves are not damp patches, but they may be associated with thin seeps of brine just below the surface. Later research suggests dust flows may also be involved. However the hydrated perchlorate salts observation still has to be explained, as well as the seasonal timing, not correlated with the winds. It's considered to be good evidence that there is at least an element of seasonal hydration associated with the streaks. The literature on this topic has a vigorous dialog between researchers who favour greater or lesser elements of brines in this process.
 
▲Before these new results, scientists assumed any present day Martian life would be able to grow without oxygen. There are several possibilities for this, based on Mars simulation experiments. Martian life could include certain blue-green algae such as {{w|Chroococcidiopsis#Mars colonization|chroococcidiopsis}}, some black fungi, and some purple salt loving {{w|Haloarchaea#As exophiles|haloarchaea}} found in salt ponds and hypersaline lakes on Earth. <!--for the black fungi, Zakharova et al paper in background information-->
 
However oxygen rich brines would permit a more energy intensive metabolism and perhaps even true multicellular animal life such as simple sponges. Almost all complex multicellular life uses oxygen.
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