What are these weird rocks in the ocean? They look strange, but otherwise, they’re kinda whatever. They’re just boring old rocks, right? Well, these weird rocks are very old. So old that they actually harbor the oldest lifeforms still on Earth. These are stromatolites.
Stromatolites are layered structures created by various species of microorganisms, such as cyanobacteria. The oldest known stromatolite fossils are 3.4 billion years old, making their lineage more ancient than any other organism on Earth. Sure, they may not be as exciting as other prehistoric life, such as the dinosaurs, but they’re still pretty cool. If you were on Earth billions of years ago, you probably would have seen a scene just like this.
The name “stromatolite” is a combo of two Greek words that mean “layered rock”. So, just like onions (and ogres), they have many layers. But what are these layers made from? Well, they are created by various bacteria species that use photosynthesis. During their everyday routine, the bacteria produce adhesive compounds that cement sand and other sediments together to form a “microbial mat”. Over time, these mats are layered on top of each other and form the bizarre, rocky columns you see here in the video.
I filmed the stromatolites you see in my YouTube video at a place called Hamelin Pool in Shark Bay, Western Australia. That’s the kind of stuff I do as a tourist. What can I say? I’m a huge nerd for natural history.
Despite only needing the sun, oxygen, and water to survive, stromatolites are surprisingly rare today. But, back in the day, they were super common. They were at their height around 1.25 billion years ago and became less common as more complex organisms started eating them. (Man, that sucks.) That’s why they’re mostly found in hypersaline lakes and marine lagoons, where the water is too salty for most organisms to thrive and dine upon them.
Interestingly enough, some stromatolites have been found in freshwater lakes such as Pavilion Lake in British Columbia, Canada. The Pavilion Lake stromatolites are the largest known freshwater stromatolites in the world and are of special interest to space agencies. NASA and the Canadian Space Agency have been studying the lake conditions that allowed these stromatolites to prosper, so they can better understand what conditions are favorable for life on other planets.
However, while stromatolites are currently considered the oldest lifeforms on Earth, this knowledge could change. Modern discoveries of life in hydrothermal vents and theories about life originating from space could shake up the status quo. I don’t know what year you’re reading this in, but if anything new has come to light, or you have some cool knowledge about early life, please leave a comment down below! Oh, and please give this article a like and follow Tidewater Teddy! Thanks, and have a great day!