Unveiling Challenging Microbial Fossil Biosignatures from Rio Tinto with Micro-to-Nanoscale Chemical and...

Area of Science:

• Astrobiology
• Geology
• Microbiology

Background:

• Extreme environments on Earth offer analogs for extraterrestrial life.
• Rio Tinto, Spain, hosts ferric oxide and sulfate deposits similar to Mars.
• Acidic conditions in Rio Tinto challenge life and fossil preservation.

Purpose of the Study:

• Investigate fossil microbiota in Rio Tinto's extreme environment.
• Elucidate ancient extremophile communities and biosignature preservation.
• Understand potential biosignatures for early Earth and Mars.

Main Methods:

• Innovative multiscale approach combining synchrotron X-ray nanoimaging.
• Ptychographic X-ray computed laminography and nano-X-ray fluorescence.
• Subcellular resolution analysis of microfossils in geological context.

Main Results:

• Revealed intricate details of preserved microbial communities at nanoscale.
• Inferred morphotypes, ecological interactions, and taxonomic affinities.
• Identified diagenetic and metabolic affinities through chemical information.
• Uncovered previously invisible microbial-mineral interactions.

Conclusions:

• Integrated nano-to-microscale analysis bridges resolution gaps in conventional methods.
• Provides insights into biosignature preservation in acidic environments.
• Contributes to deciphering faint biosignatures for detecting extraterrestrial life.