Magnetofossils, fossilised magnetic particles from magnetotactic bacteria, have been discovered in rock varnish layers in Ladakh.Rock varnish is a dark brown to black coating that covers stable, subaerially exposed rock surfaces in arid and semiarid regions.
Key Highlights of the Study
- The analysis of the rock varnish samples from Ladakh revealed higher concentrations of oxidized manganese (Mn4+) and carboxylic acid functionality, indicating organic signatures.
- These findings suggest that the rock varnish in Ladakh, a potential Martian analogue site, contains enriched concentrations of magnetic minerals likely derived from biotic sources.
- Magnetic minerals are those that preserve a record of the Earth’s magnetic field from when they formed and can be found in rocks, sediments, and soils.
Significance
- The study offers valuable insights for astrobiology by demonstrating how life can thrive in extreme environments, such as Ladakh, the “cold desert of India.”
- The findings are crucial for planning future space missions by Indian Space Research Organisation (ISRO) and other space agencies, including Mars exploration, where identifying habitable environments is a primary goal.
- Identifying biotic signatures in rock varnish helps scientists target potential biosignatures on Mars and other planets, supporting the search for extraterrestrial life
- A biosignature is any characteristic, element, molecule, substance, or feature that can be used as evidence for past or present life.
Magentofossils
- Magnetofossils refer to fossilised remains of magnetotactic bacteria that contain magnetic minerals.
- Magnetotactic bacteria leave fossilised magnetic particles in geological records.
Magnetotactic Bacteria
- Magnetotactic bacteria are mostly prokaryotic organisms that arrange themselves along the earth’s magnetic field. It was discovered by Salvatore Bellini in 1963.
- These organisms follow the magnetic field to reach places that had optimal oxygen concentration. This process is facilitated by the presence of iron-rich crystals within their cells.
- Magnetotactic bacteria create tiny crystals of magnetite or greigite within their cells to navigate changing oxygen levels and sediment saturation in water bodies.
- Crystals within magnetotactic bacteria are arranged in a chain configuration through magnetotaxis.
- Rare giant magneto fossils are less common than conventional magnetic fossils, these are likely produced by eukaryotes rather than bacteria.