The rock on Mars is a rare and precious resource here on Earth. So far, the only samples we have are pieces of meteorites, deployed from the red planet and traveling through the solar system until they reach Earth.
A small piece of these priceless things has just been used fascinatingly: scientists have grounded a small piece of the Martian Beauty Black meteorite and used it to grow extremophile microbes.
This not only proves that life could actually exist in real Martian conditions, but also gives astrobiologists new biosignatures that they could 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 made up of different pieces of Martian crust (some of which are 4.42 ± 0.07 billion years old) and have been expelled by millions [of] years ago from the Martian surface, “said astrobiologist Tetyana Milojevic of the University of Vienna in Austria.
“We had to choose a bold enough approach to crush a few grams of Martian gemstone to recreate the possible appearance of Mars’ oldest and simplest life form.”
If ancient life existed on Mars, then of all life on Earth, it is most likely to resemble an extremophile. These are organisms that live in conditions we once thought were too hostile to sustain life, such as subzero, super-salty Antarctic lakes or volcanic geothermal springs or the lower crust of the Earth, deep beneath the seabed.
On ancient Mars, billions of years ago, we are pretty sure that the atmosphere was thick and rich in carbon dioxide. We have a sample of a part of the rock that made up the Martian crust when the planet was just a child.
Here on Earth, organisms that can fix carbon dioxide and turn inorganic compounds (such as minerals) into energy are known as chemolithotrophs, so the team of researchers looked at it as a type of organism that could have live on Mars.
“We can assume that life forms similar to chemolithotrophs existed there in the early years of the red planet,” Milojevic said.
The microbe they selected was Renewed metalosphaera, a thermoacidophilic archaea found in hot and acidic volcanic springs. It was placed on the Martian ore in a bioreactor that was carefully heated and gassed with air and carbon dioxide. The team used microscopy to observe the growth of the cells.
They have indeed grown – and the basic Black Beauty table left behind has allowed scientists to observe how the microbe used and transformed the material to build cells, leaving behind biominal deposits. They used scanning transmission electron microscopy to study these deposits up to the atomic scale.
“Grown on Martian crustal material, the microbe formed a robust mineral capsule [sic] of complexed iron, manganese and aluminum phosphates, “Milojevic said.
“Apart from the massive encrustation of the cell surface, we observed the intracellular formation of crystalline deposits of a very complex nature (Fe, Mn oxides, mixed Mn silicates). These are unique distinct features of the growth of the Noahian Martian breccia not previously observed when cultivating this microbe on terrestrial mineral sources and on a stony chondritic meteorite. “
This could provide some invaluable data in search of ancient life on Mars. The Perseverance rover, which arrived on the red planet last week, will specifically only look for such biosigns. Now astrobiologists know what it is Marcus is busy crystalline deposits show, it might be easier to identify potentially similar things in Percy’s samples.
The research also highlights how important it is to use real Martian evidence to conduct such studies, the researchers said. Although we have simulated the regular Mars available, and Martian meteorites are rare, we can get an invaluable perspective from using the real thing.
Part of Perseverance’s mission is to collect samples of Martian stone to be returned to Earth, hopefully in the next decade. Scientists will certainly look for dust, but we have no doubt that some will be allocated to extreme research.
“Astrobiology research on black beauty and other similar ‘flowers of the universe’ can provide invaluable knowledge for analyzing evidence returned from Mars to assess their potential biogenicity,” Milojevic said.
The research was published in Earth and Environment Communications.