Rock from Mars is a rare and precious resource here on Earth. So far, the only samples we have are pieces of meteorite, expelled from the red planet and traveling through the solar system until they collide with Earth.
A small piece of this valuable stuff has just been used in a fascinating way: Scientists have ground a small piece of the Martian Black Beauty meteorite and used it to grow extremophilic microbes.
Not only does this show that life could really exist in real Martian conditions, it also provides astrobiologists with new biosignatures they can use to look for signs of ancient life in the crust of Mars.
“Black Beauty is one of the rarest substances on Earth, it is a unique Martian breccia formed from several pieces of Martian crust (some dated to 4.42 ± 0.07 billion years) and ejected millions. [of] years ago from the surface of Mars, ”said astrobiologist Tetyana Milojevic of the University of Vienna in Austria.
“We had to take a pretty bold approach to crush a few grams of precious Martian rock to recreate the possible appearance of Mars’ earliest and simplest life form.”
If ancient life existed on Mars, of all life on Earth, it most likely resembles an extremophile. These are organisms that live in conditions we once thought were too hostile to support life, such as sub-zero temperatures, super-saline lakes in Antarctica, or volcanic geothermal springs, or the lower crust, deep below the sea floor.
Billions of years ago on ancient Mars, we’re pretty sure the atmosphere was thick and rich in carbon dioxide. We have a sample of some of the rock that made up the Martian crust when the planet was a baby.
Here on Earth are organisms that can bind carbon dioxide and convert inorganic compounds (such as minerals) into energy, known as chemolithotrophs, so that’s what the research team looked at as the kind of organism that may have lived on Mars.
“We can assume that in the early years of the red planet there were life forms similar to chemolithotrophs,” Milojevic said.
The microbe they chose was Metallosphaera renewed, a thermoacidophilic Archaic found in hot, acidic volcanic springs. This was placed on the mineral of Mars in a bioreactor that was carefully heated and gasified with air and carbon dioxide. The team used microscopy to observe the growth of cells.
They did indeed grow – and the Black Beauty soil mass left behind allowed the scientists to observe how the microbe used and transformed the material to build cells, leaving behind biomineral deposits. They used scanning transmission electron microscopy to study these deposits down to the atomic scale.
“The microbe was grown on the crustal material and formed a robust mineral capsule [sic] of complexed iron, manganese and aluminum phosphates, ”said Milojevic.
Apart from the massive crusting of the cell surface, we have observed intracellular formation of crystalline deposits of a highly complex nature (Fe, Mn oxides, mixed Mn silicates). of this microbe on terrestrial mineral springs and a stony chondritic meteorite. “
This could provide invaluable data in the search for ancient life on Mars. The Perseverance rover, which arrived on the red planet last week, will specifically look for such biosignals. Now astrobiologists know what the Marcus busy crystalline deposits, they may find it easier to identify potentially similar things in Percy’s samples.
The study also shows the importance of using real Martian samples to conduct such studies, the researchers said. While we have Mars regolith available, and Martian meteorites are rare, we can gain invaluable insights by using the real thing.
Part of Perseverance’s mission is to collect samples of Martian rock that will be returned to Earth, hopefully within the next decade. Scientists will no doubt scream for dust, but we have no doubt some will be reserved for extremophile research.
“Astrobiological research on Black Beauty and other similar ‘Flowers of the Universe’ can provide invaluable knowledge for the analysis of returned Mars samples to assess their potential biogenicity,” said Milojevic.
The research is published in Communications Earth & Environment