User:Robertinventor/Simple animals could live in Martian brines - Extended Interview with planetary scientist Vlada Stamenković: Difference between revisions
User:Robertinventor/Simple animals could live in Martian brines - Extended Interview with planetary scientist Vlada Stamenković (edit)
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{{date|October 25, 2019}}
Vlada Stamenković of the [[NASA]] [[Jet Propulsion Laboratory]] and colleagues have developed a chemical model of how oxygen dissolves in salty brines in the cold [[Mars|Martian]] conditions. They found that
''Wikinews'' caught up with him in an email interview to find out more about his team's research and their plans for the future.
[[File:Vlada Stamenković.jpg|thumb|right|Dr. Vlada Stamenković [[Jet Propulsion Laboratory|JPL]] ]]
This is an expanded verson of the Wikinews article [https://en.wikinews.org/wiki/Simple_animals_could_live_in_Martian_brines:_Wikinews_interviews_planetary_scientist_Vlada_Stamenkovi%C4%87 Simple animals could live in Martian brines: Wikinews interviews Vlada Stamenković] which I collaborated on, with more background information
==Intro==
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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. It would not be possible for lungs like ours to extract oxygen at all.
The Mars atmosphere has a pressure of only 0.6% of Earth's atmosphere, on average. Also it's mainly carbon dioxide; only 0.146% of that
Oxygen permits a more energy intensive metabolism, and many microbes and almost all complex multicellular life on Earth depend on oxygen. They found that cold water would take up much more oxygen than warm water. In the coldest salty water in the polar regions pf Mars, covering perhaps 6.5% of the Martian surface, oxygen levels
As interviewed by Wikinews:
:: '''VS''': Our work really opens up new possibilities for the Martian habitability, and that’s why it’s so exciting!
As previously interviewed by National Geographic (October 22 2018):
::'''Vlada Stamenković''': We were absolutely flabbergasted. I went back to recalculate everything like five different times to make sure it's a real thing.
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===Why salty water?===
'''''(background information):''''' You might wonder why they focus their research on salty solutions. What about fresh water?
However, salty brines can be liquid at well below 0 °C, for the same reason salt helps keep roads ice free. These salts also counteract the tendency of the water to evaporate at low pressures. Not only that, salts can take in water from the atmosphere too, in the process known as {{w|Hygroscopy#Deliquescence|deliquescence}}, and take up water especially easily at low temperatures.
Curiosity discovered indirect evidence of deliquescence in the equatorial regions (through humidity measurements). These regions are so dry that there is no ice in the surface soil.
===The recurring slope lineae===
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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 that 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. This 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.
[[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]]
===Significance of oxygen===
Before
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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Some {{w|Aerobic organism|aerobic}} (oxygen using) microbes can survive with as little as a millionth of a mole per cubic meter (0.000032 mg, or 32 nanograms per liter).
Their lowest
Levels in the tropical regions would be higher at the lowest points such as the floor of the {{w|Hellas Planitia|Hellas basin}}, south of the equator, where the atmospheric pressure is highest, reaching around 1% of Earth's atmosphere.
===Highest oxygen concentrations in their maps===
'''''(background information):''''' Saturated sea water is about 9 mg per liter at 20 °C ranging up to 11 mg per liter at 0 °C because cold water takes up the oxygen more readily.<!-- see for instance the two "Dissolved Oxygen" cites in the Background sources-->.▼
[[File:Halichondria panicea.jpg|thumb|Halichondria panicea or the breadcrumb sponge- Stamenković et al's paper cites research by Mills et al using this sponge which showed it can survive with only 0.002 moles per cubic meter (0.064 mg per liter). This new research suggests that these concentrations can be achieved in {{w|Supercooling|supercooled}} brines on modern Mars in polar regions.]]
[[File:PIA22546-Mars-AnnualCO2ice-N&SPoles-20180806.gif|thumb|Extents of north (left) and south (right) polar CO<sub>2</sub> ice during a Martian year. These are not photos, rather they are based on infrared data from two instruments that can study the poles even at times of complete darkness. The dry ice here reaches temperature of around -125 °C, well below its sublimation temperature of -78.5 °C, which gives an idea of how cold the Martian poles get in winter. In Vlada Stamenković et al's model the highest oxygen concentrations occur at temperatures down to -123 to -133 °C.]]
They paid particular attention to two brines, magnesium and calcium perchlorates, common on Mars. If they start off liquid, they can be {{w|Supercooling|supercooled}} to temperatures as low as -123 to -133 °C
▲'''''(background information):'''''
On Earth, worms and clams that live in the muddy sea beds require 1 mg per liter, bottom feeders such as crabs and oysters 3 mg per liter, and spawning migratory fish 6 mg per liter, all within their 0.2 moles (6.4 mg) per liter.<!-- see for instance the two "Dissolved Oxygen" cites in the Background sources-->.
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===Could Mars have creatures as active as our worms and fish?===
With this background, Wikinews asked him whether
[[File:WOA09 sea-surf O2 AYool.png|thumb|Shows how the oxygen dissolved in Earth's sea surface compares with these predicted values for Mars. From the World Ocean Atlas 2009, the values for the annual mean sea surface concentrations range from below 0.2 to above 0.4 moles per cubic meter (6.4 to 12.8 mg / liter). Values on Mars could range up to 0.2 moles per cubic meter for calcim perchlorate, and up to 2 moles per cubic meter for magnesium perchlroate, in extremely cold brines at the poles. {{Image source|Plumbago}}|alt=]]
:: {{WNIQ|Wikinews}} Does your paper's value of up to 0.2 moles of oxygen per cubic meter, the same as Earth's sea water mean that there could potentially be life on Mars as active as our sea worms or even fish?
::'''VS''': Mars is such a different place than the Earth and we still need to do so much more work before we can even start to speculate.''
'''''(background information):''''' Life gets slower and slower at lower temperatures to the point where individual microbes have lifetimes of millennia. Such life is hard to study. It's almost impossible to tell whether it is a) active and able to reproduce at those temperatures or b) active and not able to reproduce, or c) intermittently sometimes active and sometimes dormant. The reproduction can't be studied using cell counts. But the usual limit cited is -20 °C<!-- see discussion in A new analysis of Mars "Special Regions" -->. That's well above the lowest temperatures studied in the paper which go down to -133 °C. ▼
===How could life use oxygen at such low temperatures?===
▲'''''(background information):''''' Life gets slower and slower at lower temperatures to the point where individual microbes have lifetimes of millennia. Such life is hard to study. It's almost impossible to tell whether it is a) active and able to reproduce at those temperatures or b) active and not able to reproduce, or c) intermittently sometimes active and sometimes dormant. The reproduction can't be studied using cell counts. But the usual limit cited is -20 °C<!-- see discussion in A new analysis of Mars "Special Regions" -->. That's well above the lowest temperatures studied in the paper which go down to -133 °C.
<!-- This para summarizes the Schulze-Makuch paper in the background information section -->
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::'''VS''': The options are both: first, cool oxygen-rich environments do not need to be habitats. They could be reservoirs packed with a necessary nutrient that can be accessed from a deeper and warmer region. Second, the major reason for limiting life at low temperature is ice nucleation, which would not occur in the type of brines that we study.
:: {{WNIQ}} [
::'''VS''': That is possible.
'''''(background information)''''': His first suggestion here is that the cool oxygen rich reservoirs could have warmer water come up through them from below
The other possibility is that microbes can continue to function at very low temperatures in the Martian conditions. After the interview I discovered that they go into this for their paper in a section ''"3.2 The lower temperature limit for life and the potential of aerobic habitats"'' in the supplementary information.
When microbes
[[File:MarsOxides.jpg|thumb|Curiosity's discovery image for the manganese-oxide minerals at a location called "Windjana,". These require abundant water and strongly oxidizing conditions to form. With the new theory these conditions may be present on Mars today, previously thought to be only possible on early Mars.]]
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