Billions of Years Old and Vanishing Fast — Earth's Ancient Living Fossils Need Protection

Life's Oldest Signature, Carved in Stone

Long before forests reached skyward, animals walked on land, or dinosaurs rose and fell, our planet was shaped by a much smaller, more unassuming form of life — and we can still find traces of it today. These ancient fossils, the earliest visible evidence of life on Earth, are known as microbialites. They are mounded structures that come in many shapes and sizes, forming when communities of microbes either precipitate minerals or trap and bind sediment. Now, a sweeping new scientific review warns that these irreplaceable biological archives are in serious danger.

A review of 50 years of microbialite research in Western Australia, published in the journal Alcheringa, summarizes what this archive can tell us about the evolution and resilience of life on Earth. Western Australia contains an extraordinary record of microbialites: from the oldest known examples, preserved in rocks almost 3.5 billion years old in the Pilbara, to living examples in the UNESCO World Heritage area of Shark Bay. The findings paint a picture of a scientific treasure that has endured for eons — but may not survive the modern era.

What These Structures Tell Us About Our World

Stromatolites are the best-known type, with distinctive layers, while thrombolites have a clotted texture. The organisms that formed these ancient structures, largely cyanobacteria, were responsible for one of the most transformative events in Earth's history: the Great Oxygenation Event, through which microbes began releasing free molecular oxygen into the atmosphere and oceans approximately 2.5 to 2.3 billion years ago. Without that transformation, complex life as we know it — including humans — would never have emerged.

Microbialites help scientists understand where some of the earliest life lived and how it might point to fossil life on other worlds, such as Mars, the mechanisms by which Earth's atmosphere became oxygen-rich, and how life responded to past environmental upheaval — with sudden increases in microbialites often preceding or coinciding with major ecological disruption and mass extinction. Modern living microbialites — such as those found in Shark Bay and Lake Clifton — are especially vital, with researchers describing Shark Bay's living microbialites as a "Rosetta Stone" for interpreting ancient rock records.

Fragile Beyond Appearances

Despite their geological longevity and seemingly unchanging nature, microbialites are surprisingly fragile — their rock-like appearance can make this difficult to appreciate. Living microbialites can be highly sensitive to environmental disturbance, and their extremely slow growth rates mean physical damage can take decades or centuries to repair, if at all. Many modern microbialite sites face growing pressures from changes in water quality, climate change, and increasing visitation. Fossil sites remain vulnerable to over-collection and degradation.

The danger is not theoretical. At sites such as Lake Clifton and Shark Bay, some events may have already caused irreparable damage — one such example occurred in May 2024, when dozens of aurora chasers trampled 2,000-year-old thrombolites in a restricted area at Lake Clifton. An ecological site hosting those 2,000-year-old thrombolites may be damaged beyond repair after visitors hoping to catch the aurora australis were seen walking in restricted areas. Meanwhile, at Shark Bay, the structures are becoming increasingly threatened by climate change, as stromatolite growth is vulnerable to rising sea levels and extreme climate events.

An Urgent Call for Protection

Compounding these scientific uncertainties is a lack of structural protection — as geological features, microbialite sites fall under geoheritage, which remains poorly recognized and under-resourced at both federal and state levels in Australia. Scientists are still debating how to distinguish structures built by life from those produced by non-biological processes, and researchers cannot always say with certainty what environments ancient microbialites formed in. These knowledge gaps make the urgency of preservation even more acute — we may lose these sites before we fully understand them.

The stakes extend well beyond scientific curiosity. Microbialites are a direct, physical link to the very origins of life on this planet. Every footprint left in a restricted zone, every specimen pocketed as a souvenir, every degree of ocean warming chips away at a record that took billions of years to write. The new research is a reminder that some of the most ancient things on Earth are also the most vulnerable — and that protecting them requires both stronger policy and a more informed public willing to treat these living relics with the reverence they deserve.