Investigating the biological potential of galactic cosmic ray-induced radiation-driven chemical disequilibrium in the Martian subsurface environment

TL;DR

This paper explores the potential for microbial life in the Martian subsurface driven by radiation-induced chemical disequilibrium caused by galactic cosmic rays, proposing a new method for detecting extant life.

Contribution

It introduces the concept of GCR-induced radiolytic zones as potential habitats for life and discusses how this could be explored with the Rosalind Franklin rover.

Findings

GCR radiation can create chemical disequilibrium suitable for microbial metabolism.

Subsurface environments on Mars may host life using radiation-driven redox chemistry.

Potential for future exploration of GCR-induced biosignatures on Mars.

Abstract

There is growing evidence suggesting the presence of aqueous environment on ancient Mars, raising the question of the possibility of life in such an environment. Subsequently, with the erosion of the Martian atmosphere resulting in drastic changes in its climate, surface water disappeared, shrinking habitable spaces on the planet, with only a limited amount of water remaining near the surface in form of brines and water-ice deposits. Life, if it ever existed, would have had to adapt to harsh modern conditions, which includes low temperatures and surface pressure, and high radiation dose. Presently, there is no evidence of any biological activity on the planet's surface, however, the subsurface environment, which is yet to be explored, is less harsh, has traces of water in form of water-ice and brines, and undergoes radiation-driven redox chemistry. I hypothesize that Galactic Cosmic Ray (GCR)-induced radiation-driven chemical disequilibrium can be used for metabolic energy by extant life, and host organisms using mechanisms seen in similar chemical and radiation environments on Earth. I propose a GCR-induced radiolytic zone, and discuss the prospects of finding such life with Rosalind Franklin rover of the ExoMars mission.