Biosignatures & Paleobiology

An Astrobiological Perspective on Microbial Biofilms: Their Importance for Habitability and Production of Detectable and Lasting Biosignatures

By Keith Cowing

Status Report

Applied Environmental Microbiology via PubMed

March 29, 2025

Filed under acid lakes, Applied Environmental Microbiology via PubMed, Biofilm, biogeochemistry, Biosignatures, deserts, habitability, hydrothermal vent systems, microbiology, polar ice

An Astrobiological Perspective on Microbial Biofilms: Their Importance for Habitability and Production of Detectable and Lasting Biosignatures — Schematic diagram of the implications of microbial biofilms for astrobiology. Biofilms expand the habitability of microorganisms by shielding them from extreme conditions. This protective function is largely attributed to the EPS, which comprises exopolysaccharides, proteins, lipids, and e-DNA. In addition, biofilms are a promising source of biosignatures, as some components of EPS are highly resistant to degradation. EPS play a crucial role in biomineralization, the process by which microorganisms facilitate mineral formation, often in discrete and easily discriminated structures. The interactions between EPS and minerals further contribute to the preservation of these biopolymers, making them valuable indicators of microbial life on Earth and in extraterrestrial environments. — Applied Environmental Microbiology

The search for life elsewhere in the universe has remained one of the main goals of astrobiological exploration.

In this quest, extreme environments on Earth have served as analogs to study the potential habitability of Mars and icy moons, which include but are not limited to hydrothermal vent systems, acid lakes, deserts, and polar ice, among others.

Within the various forms that life manifests, biofilms constitute one of the most widespread phenotypes and are ubiquitous in extreme environments. Biofilms are structured communities of microorganisms enclosed in a matrix of extracellular polymeric substances (EPS) that protect against unfavorable and dynamic conditions.

These concentrated structures and their associated chemistry may serve as unique and persistent signatures of life processes that may aid in their detection. Here we propose biofilms as a model system to understand the habitability of extraterrestrial systems and as sources of recognizable and persistent biosignatures for life detection.

By testing these ideas in extreme analog environments on Earth, this approach could be used to guide and focus future exploration of samples encompassing the geologic record of early Earth as well as other planets and moons of our solar system.

An astrobiological perspective on microbial biofilms: their importance for habitability and production of detectable and lasting biosignatures, Applied Environmental Microbiology via PubMed (open access)

Astrobiology,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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