Deserts are often thought of as barren places that are left exposed to the extremes of heat and cold and where not much is afoot. But that view is being altered as new research reveals the intricate ecological dynamics of deserts as they change in response to the elements.
New research from Arizona State University shows how microbes can significantly warm the desert surface by darkening it, much in the same way that dark clothes will make the wearer feel warmer in sunlight. These desert-darkening organisms make a living basking in the sun and form a mantle that covers the landscape.
Such mantles, called biological soil crusts or biocrusts, provide important ecosystem services, such as fighting erosion, preventing dust storms or fertilizing the ground with carbon and nitrogen.
The new ASU research shows how the biocrust microorganisms, in an effort to protect themselves from harmful ultraviolet rays in the strong desert sun, produce and lay down so much sunscreen as to noticeably darken the soil, changing the reflectivity of the desert surface as they spread across the land.