Mature Biocrust (IMAGE) U.S. Geological Survey Caption On the Colorado Plateau, mature biocrusts are bumpy and dark-colored due to the presence of lichens, mosses, and high densities of cyanobacteria and other organisms. These organisms perform critical functions, such as fertilizing soils and increasing soil stability, therefore reducing dust. Credit Jennifer LaVista, USGS Public domain Usage Restrictions Credit: USGS License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.