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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[[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.]]
'''''(background information):''''' Stamenković et al in their paper cite research from 2014 that showed that some simple sponges can survive with only 0.002 {{w|Mole (unit)|moles}}per cubic meter (0.064 mg per liter) <!-- first page of Nature paper, "Meanwhile, whereas aerobic microbial life and simple animals need O<sub>2</sub> dissolved in liquids in sufficiently large concentrations to survive, recent experiments, observations and calculations have lowered the required limits of concentrations of dissolved O<sub>2</sub> for aerobic respiration to ~10−6 mol m−3 in microorganisms and to ~2 × 10−3 mol m−3 in sponges"-->. Some microbes that need oxygen can survive with as little as a millionth of a mole per cubic meter (0.000032 mg, or 32 nanograms per liter). In their model, they found that there can be enough oxygen for microbes throughout Mars, and enough for simple sponges in oases near the poles.
A historical 101 on multicellular life on Mars may be of interest here. First, of course back in the early twentieth century there was much speculation about multicellular life there, with Lowell even speculating that intelligent Martians built the canals that he thought he could see in his telescope. By the time of early spaceflight it was already clear that the atmosphere was far too thin for terrestrial animals, but there was some hope for plant life. But the early observations from space showed a barren crater covered land and since then the idea of life on Mars has focused mainly on anaerobic microbes and photosynthetic life. ▼
<!-- For next para: Vera et al in the background information is an example of papers on lichens such as Pleopsidium chlorophanum for Mars and the DLR source gives an overview of their experiments into lichens and blue-green algae-->▼
In 2014, however, Vera et al surprised many astrobiologists with their experimental result that multicellular life could be possible on present day Mars. But only photosynthetic life able to produce its own oxygen. Some lichens, such as {{w|Pleopsidium chlorophanum}} are able to survive in close to Mars-like conditions high up on Antarctic mountain ranges, and show promise in Mars simulation chamber experiments. They can do this because the algal component is able to make the oxygen needed by its fungal component. They can also do this without needing any extra water as intermediary, in the experiments they are able to grow in partial shade, using only the night time humidity of the atmosphere itself.▼
In principle you could also have microscopic (sub millimeter sized) multicellular animals in anoxic conditions. There are only a three species of such creatures known on Earth, however, and they are not candidates for life on Mars. They are three species of {{W|Loricifera#In_anoxic_environment| Loricifera}}, tiny animals about the size of a large amoeba, are able to survive without oxygen in deep extremely salty mud sediments in the Mediterranean.<!--See sources in linked Wikipedia article and: Animals thrive without oxygen at sea bottom in background sources -->▼
This new research greatly expands the possibilities for complex life on Mars. The paper includes a map of potential brine oxygen concentrations for calcium perchlorates brines on the surface of Mars (their [https://www.nature.com/articles/s41561-018-0243-0/figures/3 figure 3a]). These 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 and lowest of all in the mountainous tropical southern uplands. But the highest values of all would be for brines at the poles.
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The paper is available to read in its entirety through the link provided on the author's website and the Nature Sharedit sharing initiative.
==Background information - historical context==
▲A historical 101 on multicellular life on Mars may be of interest here. First, of course back in the early twentieth century there was much speculation about multicellular life there, with Lowell even speculating that intelligent Martians built the canals that he thought he could see in his telescope. By the time of early spaceflight it was already clear that the atmosphere was far too thin for terrestrial animals, but there was some hope for plant life. But the early observations from space showed a barren crater covered land and since then the idea of life on Mars has focused mainly on anaerobic microbes and photosynthetic life.
▲<!-- For next para: Vera et al in the background information is an example of papers on lichens such as Pleopsidium chlorophanum for Mars and the DLR source gives an overview of their experiments into lichens and blue-green algae-->
▲In 2014, however, Vera et al surprised many astrobiologists with their experimental result that multicellular life could be possible on present day Mars. But only photosynthetic life able to produce its own oxygen. Some lichens, such as {{w|Pleopsidium chlorophanum}} are able to survive in close to Mars-like conditions high up on Antarctic mountain ranges, and show promise in Mars simulation chamber experiments. They can do this because the algal component is able to make the oxygen needed by its fungal component. They can also do this without needing any extra water as intermediary, in the experiments they are able to grow in partial shade, using only the night time humidity of the atmosphere itself.
▲In principle you could also have microscopic (sub millimeter sized) multicellular animals in anoxic conditions. There are only a three species of such creatures known on Earth, however, and they are not candidates for life on Mars. They are three species of {{W|Loricifera#In_anoxic_environment| Loricifera}}, tiny animals about the size of a large amoeba, are able to survive without oxygen in deep extremely salty mud sediments in the Mediterranean.<!--See sources in linked Wikipedia article and: Animals thrive without oxygen at sea bottom in background sources -->
==Background information - why oxygen is so significant for multicellular life==
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