Do you know what a microbialite is? Not many people do. This is because microbialites look like slimy underwater rocks, but they are actually reefs made up of microbes (simple, one-celled organisms). Microbialites are fascinating, because these rock-like structures are made by the interaction of millions of microbes that live in certain aquatic environments. The microbes facilitate the precipitation of minerals from the water, to form the microbialite structure. Since microbialites are like rocks, they have remained on earth since extremely ancient times. Fossilized microbialites, known as stromatolites (from the Greek strõma, meaning bed or layer, and lithos, meaning rock), are the oldest evidence of life on Earth, dating back to 3.7 billion years ago.
Cyanobacteria are one type of microbe found in microbialites, and these bacteria do all kinds of important work. Cyanobacteria build shelters that protect the microbial community from dangerous things in the environment, including protecting them from drying out and from damage by the sun's UV rays. The shelters built by cyanobacteria trap and bind sediments and minerals, which help to grow the microbialites.

License information: CC BY 4.0
MPAA: G
Go to source: https://kids.frontiersin.org/article/10.3389/frym.2019.00112