Fairy circles may mean in the end.
These regular barren patches settled in grasslands in Australia and Namibia have long been a controversy, with some researchers arguing that they could be the result Underground termite activity. But now, the most detailed surveillance effort shows that there are fairy circles Engineered by the grass itself.
Research, published in 21 September Ecology Journal, Reveals that harsh, dry conditions in Australia are sometimes clouded by heavy rains, creating a hostile crust of mud that forms the barren part of the fairy circles. But water drives this crust, creating a relative oasis on its edges where the grass can build a house. It is a self-fulfilling cycle: rain and sunny weather make the soil ever more inaccessible where there are no plants, whereas areas where the grass has managed to grow became a safe haven. , Where vegetation reduces soil temperature to 77 ° F (25 ° C), gets trapped in water and allows new seedlings to take root.
related: In Images: Angel Circle of the Namib Desert
“This is a positive response, where plants build ‘self-organized patches:’ they do ecosystem engineering to get as much benefit from limited water as possible in this harsh environment,” study lead author Stephen Getzin, of the University Göttingen, an ecologist and the Helmholtz Center for Environmental Research in Germany, wrote in an email to Live Science.
Self organizing pattern
Getzin and his colleagues previously stated that the angel circle is an example of what is called the Turing mechanism. It is a type of pattern first identified by the English mathematician Alan Turing, in which the interaction of two substances naturally produces speckled or striped patterns.
But to obtain this explanation for the bizarre spotted patterns in grasslands, researchers needed hard evidence. He installed 175 pounds (80 kg) of drone equipment and environmental monitors as a remote outpost in Newman, Australia, Western Australia, at a distance of 745 miles (1,200 kilometers). He used the drone to have a bird’s-eye view of the arrangement of fairy circles outside the city, where summer air temperatures could reach 118 F (48 C).
He also monitored fairy circles on a wide scale, setting up a weather station and soil monitoring equipment that were both barren and one inch below the vegetative parts of the landscape. The desert outside Newman is dominated by a group of grasses in the genus Trioda. This is the key to the formation of the fairy-circle pattern, Getzin said, because if there were more grass species around, they would take advantage of different ecological niches and potentially cover barren spots.
Monitoring showed that brief, intense rainfall suppressed coarse sand on the surface into fine silt and clay. The soil acts like a plug between the grains of sand, which closes the surface. Getzin said that it only takes twice as much hard rain to make this crust. After that, the rainwater goes away instead of entering the ground.
Circle of life
However, Getzin said, it also makes it possible for runoff plants to survive in the gaps between barren areas. Notably regular, honeycomb-style patterns in the form of 13-foot-diameter (4 m) fairy circles because the plants are taking advantage of this spacing as much as possible; In the end between barren circles as far away from each other as they can be. The regular, circular structure also benefits plants, as the maximum runoff of each difference is taken by the plants.
Monitoring of the soil also revealed that the soil under vegetation is much colder than the barren patch. Getzin and his team once measured the top centimeter of the barren crust at 167 F (75 C), well into the egg-frying area. The new study measured soil temperatures below 2 centimeters, which found that vegetation dramatically reduced soil temperature at midnight, when temperatures were at their highest. Getzin said cooler soil temperatures make it possible for seeds to germinate and germinate.
The area was monitored with a wildfire that sweeps the grassy desert, but the same patterns re-emerged when the grass began to zero again, researchers found.
Getzin wrote in his email, “We can show, for the first time, with many and very wide field investigations, that all the assumptions of Turing’s theory and model / theory actually meet nature.”
Getzin and his team are now doing a similar project in Namibia, where fairy tales look similar, but grow in sandy rather than clay-rich soil. Different soils mean that the mechanism for the formation of circles must be different, Getzin said, but they are still definitely forced to limit water in dry environments.
“In Namibia, how can perfectly spherical grass rings be formed if it is not a grass competition?” Getzin said.
Originally published on Live Science.