'Fairy circles' dot deserts in southern Africa, but the mystery behind their origin may have been solved.
N. Juergens / Live Science
The "artists" behind bizarre, barren, grassless rings dotting the desert of Southwest Africa have been found lurking right at scientists' feet: termites.
Known as fairy circles, these patches crop up in regular patterns along a narrow strip of the Namib Desert between mid-Angola and northwestern South Africa, and can persist for decades. The cause of these desert pockmarks has been widely debated, but a species of sand termite, Psammotermes allocerus, could be behind the mysterious dirt rings, suggests a study published today (March 28) in the journal Science.
Scientists have offered many ideas about the circles' origin, ranging from "self-organizing vegetation dynamics" to carnivorous ants. Termites have been proposed before, but there wasn't much evidence to support that theory.
While studying the strange patterns, biologist Norbert Juergens of the University of Hamburg noticed that wherever he found the dirt patches (the barren centers inside fairy circles), he also found sand termites. [See Photos of the Bizarre Fairy Circles]
Juergens measured the water content of the soil in the circles from 2006 to 2012. More than 2 inches (5 centimeters) of water was stored in the top 39 inches (100 cm) of soil, even during the driest period of the year, Juergens found. The soil humidity below about 16 inches (40 cm) was 5 percent or more over a four-year stretch.