Remote Laser-Induced Breakdown Spectroscopy of Bacterial Growths in Carbonate Rocks in a Mars-like Atmosphere

Area of Science:

• Astrobiology
• Planetary Science
• Spectroscopy

Background:

• Mars exploration requires understanding past habitable environments and biosignature preservation mechanisms.
• Microbial activity, particularly bacterial mediation in carbonate precipitation, is key to preserving biosignatures.
• Karstic caves on Earth offer analogs for studying biosignature preservation in carbonate formations.

Purpose of the Study:

• To investigate the capability of laser-induced breakdown spectroscopy (LIBS) for characterizing and discriminating cyanobacteria on carbonate substrates.
• To assess the potential of LIBS for detecting biological traces under simulated Martian conditions.
• To evaluate the influence of temporal analysis on the acquisition of molecular species from organic material.

Main Methods:

• Remote laser-induced breakdown spectroscopy (LIBS) was used for chemical characterization.
• The extremophile cyanobacterium Chroococcidiopsis sp. was analyzed under simulated Martian conditions (chemical composition and gas pressure).
• Time-resolved analysis was performed on biological samples to optimize molecular species acquisition.

Main Results:

• LIBS successfully differentiated cyanobacteria from their carbonate substrate based on molecular emission features.
• The study estimated the limits of detection for the cyanobacterium Microcystis aureginosa.
• LIBS demonstrated capability in detecting biological traces under simulated Martian environmental parameters.

Conclusions:

• LIBS is a viable technique for identifying potential biosignatures on Mars.
• Optimizing temporal conditions is crucial for effective molecular species detection in organic materials.
• This research supports the search for extraterrestrial life by validating remote sensing techniques.