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. Nitrogen fixation is another significant capability of cyanobacteria. Vascular plants are unable to utilize nitrogen as it occurs in the atmosphere.
Cyanobacteria are able to convert atmospheric nitrogen to a form plants can use.
This is especially important in desert ecosystems, where nitrogen levels are low and often limiting to plant productivity. The sheaths have other functions as well. When moistened, they swell up to ten times their dry size. This ability to intercept and store water benefits both the crustal organisms as well as vascular plants, especially in arid regions with sporadic rainfall. Sheaths, and the organisms they surround, also contribute organic matter and help make essintial nutrients available to vascular plants.