Lichens and mosses may take even longer to recover. Enlarged view of sheath material Cyanobacteria, previously called blue-green algae, are one of the oldest known life forms. It is thought that these organisms were among the first land colonizers of the earth's early land masses, and played an integral role in the formation and stabilization of the earth's early soils. The earliest cyanobacteria fossils found are called stromatolites, which date back more than 3.5 billion years. Extremely thick mats of these organisms converted the earth's original carbon dioxide-rich atmosphere into one rich in oxygen and capable of sustaining life.
Cyanobacteria occur as single cells or as filaments.
The most common form found in Colorado Plateau soils are the filamentous type, which are usually surrounded by sticky mucilaginous sheaths. When moistened, cyanobacteria become active, moving through the soil and leaving a trail of sticky material behind. In this way, loose soil particles are joined together, and an otherwise unstable surface becomes very resistant to both wind and water erosion. The soil-binding action is not dependent on the presence of living filaments. Layers of abandoned sheaths, built up over long periods of time, can still be found clinging tenaciously to soil particles, providing cohesion and stability in sandy soils at depths up to 10cm.