These organism are mainly found in deserts and other arid regions on earth. Many hikers often go unnoticed, but they have a big impact on the local vegetation: the Cryptobiotic Soil. These organisms are often referred to as »desert glue«. Because they hold the sand and other fragments together and stabilize the soil. In this way they protect the soil from water and wind erosion, which this would otherwise be defenseless. In addition, they save water and contribute nitrogen and other organic matter into the soil, which is critical in deserts where resources are scarce.
Cryptobiotic soil belong to the biological soul crust and mostly consist of cyanobacteria (blue-green algae), but also lichens, mosses, green algae, microfungi and bacteria.
These soil dwellers are very sensitive and fragile. Even a single footprint or tire track are enough to destroy them for years and sometimes centuries. And a broken crust can contribute less nitrogen and moisture. In the American National Park, visitors are advised of signs on the importance of these creatures and requested to stay on the marked trails.
The soil crusts are usually recognizable in the national parks by big black bumps on the ground, as seen in the following photos.