In a study that was literally groundbreaking, researchers uncovered microbes living deep within ancient rocks in South Africa that are over 2 billion years old. These tiny organisms have survived by colonizing mineral-filled cracks in the rocks, 15 meters below the surface. Tightly packed minerals kept the microbes isolated and provided them with a long-term source of food. This was all observable because the study developed new approaches to detect microscopic colonies in igneous rock samples that have been drilled from these depths.

References:

Suzuki, Y., Webb, S. J., Kouduka, M., Kobayashi, H., Castillo, J., Kallmeyer, J., Moganedi, K., Allwright, A. J., Klemd, R., Roelofse, F., Mapiloko, M., Hill, S. J., Ashwal, L. D., & Trumbull, R. B. (2024). Subsurface Microbial Colonization at Mineral-Filled Veins in 2-Billion-Year-Old Mafic Rock from the Bushveld Igneous Complex, South Africa. Microbial Ecology, 87(1). https://doi.org/10.1007/s00248-024-02434-8