Testing the Limits of Biosignature Detection in Ca-sulphate Mixtures Through a Simulated Martian Environment

Abstract

Mixtures of cyanobacterial microbial mat and Ca-sulphate minerals were exposed to a simulated Martian environment via the Thales Alenia Space's “MARSBalloon” Project in partnership with St Bernard’s High School via the Orbyts science inclusivity program. FTIR spectroscopic analyses identified that at 50% Ca-sulphate, most microbial mat biosignatures were obscured under Earth conditions, except for the C–O stretch and polysaccharide O–H vibrational modes. At 75% Ca-sulphate concentrations, no spectral biosignatures were observed. However, after exposure to a simulated stratospheric Martian environment, partial dehydration of the Ca-sulphate occurred to reveal the spectral biosignatures. This has implications in the search for life on Mars, particularly within evaporite-rich environments similar to those being investigated by the Curiosity rover.