Microstructural And Biochemical Constraints On Cryptoendolithic Life In Atacama Halite: Implications For Extreme Habitability

Halite pinnacles from the Yungay area in the hyperarid core of the Atacama Desert harbor cryptoendolithic microbial colonies.

A cross-section of a halite pinnacle was investigated using Raman spectroscopic imaging as the principal analytical technique, complemented by advanced fluorescence microscopy and CT-scan-based 3D visualization.

Transversal section images were analyzed to track spatial variations in biomolecular responses, with particular emphasis on pigment composition.

Overall, this study provides (a) new insights into complex halite architecture characterized by heterogeneous porosity, (b) the distribution of minor evaporitic components within the rock, specifically Ca-sulfate (gypsum) and Na-Ca sulfate (glauberite), (c) a characteristic umbrella-like pattern of scytonemin distribution revealed by both Raman and fluorescence imaging, and (d) changes in scytonemin Raman features that are interpreted as putative oxidative transformation of the pigment.

Astrobiology, biosignatures, genomics,