If you’ve ever been hiking in the deserts of Southern Utah, then you’ve probably come across strange blackish bumps in the sand. These are actually colonies of diverse groups of bacteria, and collectively they are known as biological soil crust. You can find biological soil crusts in deserts everywhere across the world, and they play a pretty important role in the environment.

What they do – Biological soil crusts fix atmospheric carbon and nitrogen, reduce soil erosion, and collect water and nutrients for surrounding plant life. Most colonies of bacteria have large populations of Cyanobacteria, which are capable of photosynthesis. And because they absorb some of the suns rays, the desert sands reflect less in areas with established soil crust. Which is good news for your eyeballs.

How they are made – Biological soil crust begins to form when fungi spores colonize the area between desert plants. Once the fungi has stabilized, Cyanobacteria and other bacteria, such as Bryophytes, congregate around the fungi structures. Eventually lichens and algae join the colony. The whole process takes a long time to complete. Depending on the amount of water available in the region, it can literally thousands of years for mature soil crust to develop.

Look but don’t touch – Biological soil crust is extremely fragile. (Which, considering how long it takes to form, is understandable.) Crushing and tearing soil crust can result in widespread colony collapse. This in turn leads to substantial soil erosion. So when you’re hiking or riding your ATV in Southern Utah, think of the little colonies all around you, and avoid any unnecessary distribution of soil crust. It’s best to stay on the designated trails whenever possible.