Stromatolite Bacteria

Cyanobacteria (Stromatolite-forming species)

Period

Archean

Location

Shallow marine environments

Length

Microscopic (1-2 µm)

Weight

Not applicable

Diet

Omnivore

Category

Microorganisms - Bacteria

Family

Cyanobacteria

About Stromatolite Bacteria

Stromatolite-forming Cyanobacteria

Overview

Stromatolite bacteria are among the oldest living things on Earth—they've been around for over 3.5 billion years! These tiny microorganisms, mainly cyanobacteria (blue-green algae), created some of the first structures visible from space and literally changed the planet's atmosphere to make life as we know it possible.

What Are Stromatolites?

Living Rock Formations

Stromatolites aren't the bacteria themselves—they're structures built by bacteria:

  • Layers of microbial mats that trap sediment
  • Slowly build up over thousands of years
  • Create dome or column-shaped rock formations
  • Some ancient stromatolites are taller than a person!

Taxonomy & Classification

  • Domain: Bacteria
  • Phylum: Cyanobacteria
  • Type: Photosynthetic microorganisms
  • Size: Microscopic (1-2 micrometers)

Why They Changed Everything

The Great Oxidation Event

Cyanobacteria performed the most important job in Earth's history:

  • They invented photosynthesis (using sunlight to make energy)
  • Released oxygen as a waste product
  • Over billions of years, filled Earth's atmosphere with oxygen
  • Made it possible for complex life to evolve
  • You can breathe today because of these tiny organisms!

Before Cyanobacteria

  • Earth's atmosphere had almost no oxygen
  • The sky was probably orange or pink, not blue
  • Only simple life forms could survive
  • The oceans were full of iron, making them green or rusty

Where to Find Them Today

Living Fossils

Stromatolites still exist in a few special places:

  • Shark Bay, Australia—the most famous location
  • Bahamas
  • Some hot springs
  • Hypersaline lakes (extremely salty water)

They only survive where other animals can't eat them (like super salty or hot water).

Ancient History

Earth's First Architects

  • Oldest stromatolite fossils are 3.5+ billion years old
  • Found on every continent
  • Were once the dominant life form on Earth
  • Built massive reef-like structures in ancient seas
  • Declined when animals evolved that could eat them

How They Build Stromatolites

  1. Sticky film of bacteria grows on a surface
  2. Sediment particles get trapped in the slime
  3. Bacteria grow over the sediment
  4. Process repeats, building layers
  5. Over thousands of years, forms solid rock

It's like building a very slow, very slimy layer cake!

Scientific Importance

Windows to the Past

Stromatolites help scientists:

  • Understand what early Earth was like
  • Search for life on other planets (Mars rovers look for stromatolite-like structures!)
  • Study how life began
  • Track changes in ancient atmospheres

Cool Facts

  • Cyanobacteria are responsible for about 20-30% of Earth's oxygen today
  • They're sometimes called "blue-green algae" but they're actually bacteria!
  • Stromatolites grow only 0.3mm per year—slower than your hair grows!
  • Some stromatolite fossils are older than most of Earth's rocks
  • Without cyanobacteria, there would be no animals, no plants, no you!
  • Living stromatolites in Shark Bay are protected because they're so rare and ancient

These tiny bacteria are proof that small things can change the world—they literally transformed Earth from a barren rock into a planet bursting with life!