Do stromatolites still exist?

Living Fossils in a Quiet Australian Lake

Nestled in Western Australia’s Cervantes region, Lake Thetis holds a quiet marvel: living stromatolites. These unassuming, rocky mounds are among the few places on Earth where you can witness life forms that once dominated ancient seas over 3 billion years ago. Stromatolites are layered structures built by colonies of cyanobacteria—microscopic organisms that use sunlight to produce energy, releasing oxygen in the process. In doing so, they helped transform Earth’s early atmosphere and paved the way for more complex life.

While fossilized stromatolites are scattered across the geological record—like those in Capitol Reef National Park, which tower in size and age—living examples are rare. The ones in Lake Thetis are modest in stature, often just a few centimeters high, but their significance is monumental. They grow slowly, layer by layer, as microbial mats trap sediment and precipitate minerals over time. Walking along the boardwalk overlooking the lake, you might miss them if you’re not looking closely. But beneath the surface, they’re carrying on a legacy older than dinosaurs, older than most life we recognize today.

Most modern environments are too competitive for stromatolites to thrive. Grazing organisms and shifting ecosystems usually prevent their formation. But Lake Thetis, with its saline, undisturbed waters, offers a refuge—much like the conditions of early Earth. This unique balance allows these ancient architects to persist, quietly testifying to the resilience of life.

Seeing stromatolites isn’t just a glimpse into a remote past—it’s a reminder that the oldest forms of life are still with us, whispering stories of a planet in its infancy.