Stromatolites

Definition

Stromatolites are layered structures formed by the trapping, binding, and cementation of sedimentary grains by microorganisms, primarily cyanobacteria. They are among the oldest known fossils, providing crucial evidence of early life on Earth.

5 Must Know Facts For Your Next Test

1. Stromatolites date back over 3.5 billion years, making them some of the earliest evidence of life on Earth.
2. Modern stromatolites can still be found in a few locations around the world, such as Shark Bay in Australia.
3. The microorganisms involved in forming stromatolites are predominantly cyanobacteria, which perform photosynthesis and contributed to the oxygenation of Earth's atmosphere.
4. Stromatolite formations provide insights into ancient environments and the conditions that supported early microbial life.
5. Studying stromatolites helps astrobiologists understand potential biosignatures that might indicate past or present extraterrestrial life.

Review Questions

• What role do cyanobacteria play in the formation of stromatolites?
• Why are stromatolites significant for understanding early life on Earth?
• How do modern stromatolite formations help scientists study ancient microbial ecosystems?

Related terms

Cyanobacteria: Photosynthetic microorganisms that played a key role in oxygenating Earth's atmosphere and are essential to the formation of stromatolites

Biosignature: Any substance – such as an element, isotope, molecule, or phenomenon – that provides scientific evidence of past or present life

Extremophile: An organism that thrives in extreme environmental conditions where most life forms cannot survive