Why in news?
Scientists studying the Salar de Pajonales, a high‑altitude salt flat in Chile’s Atacama Desert, have found that gypsum rocks there protect microbes from extreme conditions. The findings, published in March 2026, have implications for the search for ancient life on Mars, where gypsum deposits are abundant.
Background
The Salar de Pajonales sits 3.5 kilometres above sea level and is blasted by ultraviolet radiation and freezing temperatures. Its environment closely resembles that of Mars. Researchers focused on gypsum (CaSO4·2H2O), a translucent mineral known on both Earth and Mars. They studied stromatolites – layered structures built by microbes over long periods.
Key findings
- Shallow refuge: Living microbes were found just millimetres beneath gypsum’s surface. The mineral admits enough light for photosynthesis while blocking harmful radiation and trapping moisture, creating a micro‑habitat in an otherwise hostile desert.
- Preservation of fossils: Deeper inside the stromatolites, researchers found fossilised remains and chemical signatures of ancient life. Gypsum sealed these remains, preserving evidence of past biological activity.
- Implications for Mars: Mars orbiters have detected large gypsum deposits. If gypsum shelters and preserves life on Earth under extreme conditions, similar deposits on Mars might hold signs of past microbial life. Future missions could target such deposits.
Significance
- Understanding extremophiles: The study shows how life can survive in extreme environments by exploiting protective minerals.
- Planetary exploration: Provides a promising strategy for astrobiologists seeking biosignatures on Mars and other planetary bodies.
- Geological insight: Highlights the role of evaporite minerals like gypsum in preserving Earth’s early biosphere.
Source: The Hindu