>https://www.nps.gov/articles/seug-soil-crust.htm https://www.nps.gov/articles/seug-soil-crust.htm Living soil which can be destroyed by footsteps. Cyanobacter

>https://www.nps.gov/articles/seug-soil-crust.htm https://www.nps.gov/articles/seug-soil-crust.htm Living soil which can be destroyed by footsteps. Cyanobacteria and lichens and algae. One of the oldest organisms on Earth.