Fossil Hotspot: Shark Bay, Western Australia
Why Shark Bay Matters
Shark Bay, a UNESCO World Heritage Site in Western Australia, is one of the few places on Earth where you can find living stromatolites—layered rock-like structures made by microbial communities (mostly cyanobacteria). These living fossils are nearly identical to fossilized stromatolites that date back over 3.5 billion years!
Shark Bay gives us a glimpse of what Earth might have looked like long before animals evolved. It’s a real-time look at the kind of life that once dominated the planet.
What Are Stromatolites?
Stromatolites form when microbes like cyanobacteria trap and bind layers of sediment. Over time, this builds up into mounded or column-shaped structures.
- Ancient stromatolites are some of the oldest fossils on Earth.
- Modern stromatolites in Shark Bay are created the same way—by living bacteria!
- Living Fossils: Stromatolites show us how early microbial life looked and functioned.
- Oxygen Makers: The microbes that built stromatolites were likely the first organisms to use photosynthesis and produce oxygen—eventually changing Earth’s atmosphere.
- Extreme Conditions: Shark Bay’s super-salty waters protect stromatolites from predators, creating conditions similar to ancient shallow seas.
- Stromatolite: A layered rock formed by microbial mats, especially cyanobacteria.
- Microbial mat: A thick sheet of microorganisms that can trap sediments and build stromatolites.
- Cyanobacteria: Ancient bacteria that perform photosynthesis and helped oxygenate the Earth.
- Stromatolite Simulation: Layer playdough in different colors to model how stromatolites form over time.
- Where is Shark Bay? Find it on a globe or map.