Mystery of Fairy Circles

In parts of Africa and Australia, wide expanses of desert grasslands are pockmarked with perfect circles of bare red soil. For years, scientists have debated their possible cause, but in 2017, researchers may have finally cracked the mystery.



The Prevailing Theories

Fairy circles can range from 6 to 115 feet (2 to 35 meters) in diameter and sit in regularly spaced hexagonal or honeycomb patterns in the grass. Some scientists, like University of Hamburg's Norbert Juergens, believe that they're caused by sand termites. The termites, he believes, eat all the grass in the circle to expose the sand, which traps rainwater and saves it for a particularly dry day. "They're like desert versions of beaver dams," writes Ed Yong for National Geographic.
Other researchers say the cause is a plant, not an animal. In the desert, resources are scarce, and the deep-rooted grasses must battle over water and nutrients. Through their battles, they drain water from a central reservoir where other plants can't grow, thereby self-organizing into rings around that reservoir. The surprisingly organized pattern of fairy circles suggests that this could be a better theory than the termite version.



The New Research

The latest research says, to quote a popular meme, "why not both?" In a paper published in Nature in 2017, researchers suggest that both termites and plants are what's causing the mysterious fairy circles. Their computer models showed that either theory worked to form bare circles of soil, but when they tested both together, a second pattern formed between the circles.
When they ventured out to Namibia to confirm their theory, sure enough, the secondary pattern was there. That, says The New York Times, "confirmed that their mathematics reflected reality and suggested that only by interacting together could insects and plants create the landscape that characterizes Namibian fairy circles."

Source : Curiosity

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