A Cryptobiotic soil is a biological soil crust composed of living cyanobacteria, green algae, brown algae, fungi, lichens, and/or mosses. Commonly found in arid regions around the world, cryptobiotic soils go by many names, including cryptogamic, microbiotic, or microphytic soils or crusts. Soil crusts are important members of desert ecosystems and contribute to the well-being of other plants by stabilizing sand and dirt, promoting moisture retention, and fixing atmospheric nitrogen. For the heavy metal band see Soil (band) Soil is a general term for the material that lies on the surface of the earth, supporting the growth of plants and serving as a habitat for animal life from microrganisms to small animals. ... Cyanobacteria (Greek: cyanos = blue) are a phylum of aquatic bacteria that obtain their energy through photosynthesis. ... Divisions Chlorophyta Charophyta Streptophytina (Subdivision) The green algae are the large group of algae from which the embryophytes (higher plants) emerged. ... Orders Dictyotales Desmerestiales Fucales Laminariales (kelps) etc. ... Divisions Chytridiomycota Zygomycota Glomeromycota Ascomycota Basidiomycota Yellow fungus For the fictional character, see Fungus the Bogeyman. ... Crustose and foliose lichens on a wall Foliose lichen on basalt Usnea australis, a fruticose form, growing on a tree branch Lichen on rock Lichens are symbiotic organisms made up by the association of microscopic green algae or cyanobacteria and filamentous fungi. ... Subclasses Andreaeidae Sphagnidae Tetraphidae Polytrichidae Buxbaumiidae Bryidae Archidiidae Moss is a type of simple or non-vascular plant, of the class Musci, in the division Bryophyta, that have rhizoids instead of true roots. ... A dune in the Egyptian desert Desert in California In geography, a desert is a landscape form or region that receives little precipitation. ... In ecology, an ecosystem is a naturally occurring assemblage of organisms (plant, animal and other living organisms—also referred to as a biotic community or biocoenosis) living together with their environment (or biotope), functioning as a unit of sorts. ... Nitrogen fixation is the process by which nitrogen is taken from its relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds useful for other chemical processes (such as, notably, ammonia, nitrate and nitrogen dioxide). ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ...

Because of their thin, fiberous nature, cryptobiotic soils are extremely fragile systems. A single footprint or tire track is sufficient to disrupt the soil crust and damage the organisms. While some species within the soil crust system may regrow within a few years of a disturbance, the damage to slow-growing species may require more than a century before the delicate soil returns to its former productivity.

This sensitivity to disturbance means that travelers in arid regions should be mindful of their impact on cryptobiotic soils. As a general rule, visitors should stay on pre-existing roads and trails, only traveling off-trail on durable surfaces such as bedrock or river gravel.