Ground Truths.

The article focuses on the views of the author regarding the ecology and the role of the biological soil crusts in the biological community in the U.S. Topics discussed include protection of soil from erosion, maintenance of the physical and biological balance of the ecosystem and nitrogen fixation of the soil through several microorganisms including cyanobacteria, lichen and mosses for nourishment of plants. She further discusses the diversity and activity of crust microorganisms.