Earth’s oldest evidence of life is written in stone – but it’s at risk of disappearing

Earth's oldest evidence of life is documented in stone formations known as microbialites, primarily located in Western Australia. These ancient structures, preserved in rocks almost 3.5 billion years old, provide vital insights into the evolution and resilience of life on our planet. However, these fragile fossils are at risk of disappearing due to various threats.

Microbialites are mounded structures formed by communities of microbes, which can precipitate minerals or trap and bind sediment. Two main types exist: stromatolites, characterized by distinctive layers, and thrombolites, with a clotted texture. The presence of both types in Western Australia's Shark Bay highlights their significance as a "Rosetta Stone" for understanding fossil counterparts.

The microbialite record reveals important information about life on Earth, including where some of the earliest life lived and how our atmosphere became oxygen-rich. Living microbialites in Shark Bay serve as crucial indicators of past ecological stress and may even offer clues to life beyond our planet.

However, these ancient formations face numerous dangers. Fossil sites are vulnerable to over-collection and degradation, while living microbialites are under threat from environmental changes, increasing visitation, and even tourism activities. As geological features, they fall under geoheritage protection, but this area of heritage remains poorly recognized and under-resourced in Australia.

The review of 50 years of microbialite research in Western Australia emphasizes the importance of preserving this ancient archive, both living and fossil, for future scientists to answer unanswered questions and potentially ask new questions. The loss of microbialite archives would not only hinder our understanding of today's ecosystem challenges but also prevent the investigation of both current and future questions.