A life of true Martian design

Early Mars was considered an environment where life could exist. There was a time in the geological history of Mars when it could be very similar to Earth and harbored life as we know it. Compared to the normal conditions at Mars, Mars’ early history may have melted water bodies, warmer temperatures, and higher atmospheric pressure. Early lifestyles on Mars should be able to harness accessible deposits of the red planet: extracting energy from inorganic mineral sources and converting CO2 into biofuels. These living units, called “chemolithotrophs”, are rock-eating microorganisms that are capable of converting rock energy into life energy.

Martian rocks as an energy source for ancient life forms

“We can assume that life forms resembled chemolithotrophs there in the early years of the red planet,” says astrobiologist Tetyana Milojevic, head of the Space Biochemistry group at the University of Vienna. Traces of this ancient life (biosignatures) may be preserved within Noachian land with an ancient geological history full of moisture and mineral springs that may have been inhabited by chemolithotrophs. To properly assess relevant Martian biosignatures, it is extremely important to consider chemolithotrophs in relevant Martian mining situations.

One of the rare pieces of Mars rock was recently crushed to see what life based on Martian materials would look like. The investigations used the true Noachian Martian breccia North West Africa (NWA) 7034 (nicknamed “Black Beauty”) to grow the true thermoacidophile Metallosphaera sedula, a former inhabitant of terrestrial thermal springs. This brecciated regolith sample represents the oldest known Martian crust of the ancient crystalline ages (chap. 4.5 Ga).

Sample of “Black Beauty”

“Black Beauty is among the rarest products on Earth, it is a unique Martian breccia created with various pieces of Martian bark (some of which date at 4.42 ± 0.07 billion years) and on cleared a million years ago from the Martian surface We had to choose a very bold approach to crushing a few grams of precious Martian rock to the possible view of the earliest and simplest form of life. at Mars reconstruction, “said Tetyana Milojevic, the study ‘s co – author, about the probe donated by colleagues from Colorado, USA. .

As a result, the researchers looked at how the delicate dark landscape of Black Beauty was modified and used to build basic components of microbial cells in the form of biomineral deposits. Using a complete toolbox of advanced techniques in fruitful collaboration with the Austrian Center for Electron Microscopy and Nanoanalysis in Graz, the researchers explored specific microbial interactions with the real Noachian Martian breccia down to nanoscale and atomic solution. M. sedula inhabited by Martian crustal material gave specific mineral and metabolic fingerprints, which allow the detection of putative bioalteration processes of Martian crust.

Investigating metabolic and mineral fingerprints

“Grown on Martian crucible material, the microbe created a strong mineral capsule made up of complex iron, manganese and aluminum phosphates. In addition to the sheer size of the cell surface, we have intracellular formation. of crystalline deposits of a very complex nature (Fe, Mn oxides, mixed Mn silicates) .These are unique growing features of Martian Noachian breccia, which we did not observe before when cultivating the this microbe on terrestrial mineral sources and stony chondritic meteorite, ”said Milojevic, who recently received ERC’s Consolidator Grant for her research further investigating the biogenicity of Martian materials.

The complex and complex biomineralization patterns of M. sedula grown on Black Beauty can be well described by the rich, diverse mineralization and multicellular nature of this ancient Martian meteorite. The specific biomineralization patterns of M. sedula cells grown in Black Beauty underscore the importance of experiments on true Martian materials for Mars-related astrobiologic studies. “Astrobiology research on Black Beauty and other‘ Earth Flowers ’can deliver priceless knowledge for the analysis of returned Mars models to assess their potential biology”, concludes Milojevic .

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Published in Land & Environment Communications:

T. Milojevic, M. Albu, D. Kölbl, G. Kothleitner, R. Bruner, M. Morgan “Chemolithotrophy on Noachian Martian breccia NWA 7034 through the mutation of experimental microorganisms. Nature Communications Land & Environment (2021), DOI: 10.1038 / s43247-021-00105-x