Identifying extraterrestrial analogue environments and reliable biosignatures on Earth is crucial for understanding potential forms of life beyond our planet. However, both these environments and the life forms within them are not yet fully understood. Lava tubes, formed by basaltic pahoehoe volcanic eruptions, are created by low-lying shield volcanoes, where surface lava flows cool and hardens while the lava inside continues to flow. This process results in cave-like structures that remain isolated from the surface environment, creating light-deprived and nutrient-poor (oligotrophic) conditions. Despite these challenging conditions, microbial life thrives within these caves. As such, lava tubes provide a unique analogue environment to explore the limits of life’s sustainability in extreme conditions.

Although the surface of Mars has not yet yielded evidence of life, its subsurface remains a protected environment where signs of past or present life could be preserved. Thus, lava tubes on Mars present a compelling opportunity to search for any potential life that may have once existed or still resides beneath the surface. The process of lipid biosynthesis is energetically demanding and rarely occurs abiotically, making lipids a promising biosignature for life on other planets. Lipids are known for their relative resistance to non-biological degradation, their role in compartmentalization, and their importance in regulating extremophile survival in harsh terrestrial environments.

Our previously published paper, ”A Study in Blue: Secondary Copper-Rich Minerals and Their Associated Bacterial Diversity in Icelandic Lava Tubes”, measured carotenoid signals using Raman spectroscopy in a blue colored microbial sample. Thus, we hypothesize that some classes of lipids, such as carotenoids, may provide protective functions to microbial life and could serve as useful, enduring biosignatures in analogue environments like lava tubes due to their chemical properties that make them easily identifiable. Utilizing liquid chromatography-mass spectrometry (LCMS), we identified specific lipids and lipid metabolisms present in bacterial samples collected from lava tubes in Iceland. Here, we report a primary abundance of carotenoids and coenzymes that may serve as promising biosignatures within these extremophile environments.

Joleen Csuka, LATMOS.

Location
LATMOS
Guyancourt
Room 2202

Zoom
https://cnrs.zoom.us/j/99053682180?pwd=7aESmWZjtU2mgRdK3j70fnB8uRkVed.1

Online:

https://cnrs.zoom.us/j/99053682180?pwd=7aESmWZjtU2mgRdK3j70fnB8uRkVed.1