O search for life on Mars and elsewhere in the universe depends a lot on understanding how we identify it and the footprints it leaves on our own planet. But detecting biological traces in ancient terrestrial rocks is a challenge due to the physicochemical changes they experience over time.

Because of this, the use of chemical fossils, like certain biomolecules or isotopic compositions, is very useful in the search for life in ancient environments, where the accumulated impact of several destructive factors such as ultraviolet radiation, erosion, pressure or temperature have been able to cause the gradual degradation of possible biological debris.

A multi-analytical platform was applied to detect traces of life in rocks more than 200 million years old in the Atacama Desert (Chile) as training system for future astrobiological missions on Mars and other places outside the Earth.

Now, a multidisciplinary team from the Astrobiology Center (TAXI, CSIC-INTA) and the Universidad Católica del Norte (Chile) publish study, magazine cover astrobiology, where they are presented molecular and isotopic biomarkers preserved in ancient rocks of the Chilean desert of atacama.

Specifically, the authors analyzed samples of three sedimentary rocks (marine carbonates) from the Triassic-Jurassic with the aim of identifying traces of life over the last 200 million years.

as pointed out Laura Sánchez-García, a CAB researcher who led the study, “it is essential to combine the search for multiple target molecules with different chemical compositions, degrees of conservation and biological specificity to complement the limited biological or temporal information that each provides at an individual level.”

“In this way, a more inclusive image of what the original environment was like is achieved”, he adds. The application strategy multiple biomarkers, which cover different chemical aspects and complexities, increases the probability of detecting unmistakable signs of life”.

A multi-analytics platform

In the study, a multi-analytical platform was applied to detect different types of biomolecules with different resistance to degradation and the ability to diagnose their biological sources. The combined identification of lipid and protein-derived molecules with the positive signals from a life detector chip (called life detector chip) allowed us to infer the metabolism and diversity of the most recent life forms.

The strategy of applying multiple biomarkers, covering different chemical aspects and complexities, increases the probability of detecting unambiguous signs of life.

Laura Sánchez-García (CAB)

Molecular and isotopic analysis of lipid chains (the most resistant to degradation) also made it possible to identify biological sources from older times, as well as to recreate the environmental conditions that prevailed in the last 200 million years.

According to the authors, “the detection of extraterrestrial life can benefit from this approach, as we can detect biomarkers at different levels of chemical complexity, which allows us to overcome diagnostic limitations due to the lack of specificity and/or degradation over a period of time. a long time. geological “.

The researchers conclude that similar strategies must be considered to interpret the results of current missions in Mars, as well as for the future astrobiology of the red planet, which foresees the use of detection techniques such as those used in this work.

Rights: Creative Commons.

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