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Mysterious Fairy Circles In Africa The Work Of Sand Termites

March 29, 2013
Image Caption: Fairy circles in Namibia’s Hartmann Valley. Credit: Juergens, Science/AAAS

Lawrence LeBlond for redOrbit.com – Your Universe Online

Mysterious crop circles started appearing in regular fashion across the UK in the 1970s, leading to many theories about their origin. As they grew in popularity, and began taking on very peculiar shapes, sizes and design patterns, many pointed to the stars, blaming ET for the crop-damaging, yet extraordinarily-elaborate patterns in the fields of the English countryside. And as these spherical designs became more and more elaborate, some started claiming responsibility for them, and others showed how the task is accomplished.

Numerous tests, experiments, analyses and measurements have been conducted throughout the years to try and determine if these crop circles were left here from otherworldly visitors or just plain hoaxes, as so many have claimed. While the debate is still in the air, another wave of circular formations has been garnering some attention in Africa and abroad.

In particular, a large swath of landscape in the southwest corner of the continent has become home to a mysterious trove of barren patches of land in otherwise grassy terrain. These bare circular patterns have become known as fairy circles and have been as nearly mysterious in nature as the aforementioned crop circles for longer than a lifetime.

These small circles, thousands of them, seem as though they are alive, growing and shrinking and existing anywhere from 30 to 60 years. There are a number of myths about the origin of the spherical objects with locals leaning toward the work of supernatural entities. Scientists have been studying these formations for decades and have just as many crazy answers as they do questions.

They were made by giant underground creatures; radioactivity created these formations; a new wave of deadly plants killed off their rivals; toxic gas is being released from the ground. While the answers seem almost as mysterious as the fairy circles themselves, one German scientist claims that none of these ideas hold any water.

HOLDS WATER

In fact, Norbert Juergens, of the University of Hamburg, said the fairy circles themselves do hold water. According to his research, the circles are water traps created by sand termites. These termites eat all the grass within a circular patch, exposing the underlying sand grains that store falling rainwater. He said these barren patches are ecological engineering feats, designed to retain water in an otherwise arid landscape.

Juergens said these patches are the termite versions of beaver dams. The circular water holes dot a narrow stretch of desert from Angola to Namibia and into northern South Africa.

Studying these fairy circles for years, he has examined hundreds of them in detail. The outer rings are delicately engineered to first retain and then maintain a supply of water for the termites in their environment. These invertebrates (Psammotermes allocerus) first clear a patch of ground by eating the roots of annual grasses, which becomes an effective rain trap — with no vegetation, the water cannot be lost through transpiration (evaporation through plant contact).

Instead, the water collects just below the surface where it can sustain the termites, as well as perennial grasses that exist at the margins of the circles. The process is part of a larger cycle, explained Juergens. While the termites are preserving their own way of life and the grasses around them, they are also sustaining other creatures in the environment which subsist on a diet of termites, such as geckos, moles, aardvarks, spiders, ants and jackals.

Juergens said that the fairy circles are an engineering marvel that surpasses even the work done by another great ecosystem engineer — the beaver.

“We all admire the beaver for the way it can turn a linear river into a lake with a dam, but the termites turning the desert into a pattern of oases that allow permanent life even in drought periods for hundreds of years – that’s much more fascinating,” he told BBC News.

“What is more, these termites do it on a large scale – over hundreds of square [miles]. They should replace the beaver as the text-book engineer.”

DETAILED EXAMINATION

Juergens was drawn to the circles through his involvement with Biota Africa, a project devoted to studying and conserving Africa´s wildlife. Over the course of 40 field trips, Juergens carefully examined the delicate ecosystem, taking a count of all the creatures living near the circles across the entire range. He not only checked what was living above ground, but what was thriving below as well.

His work led him to a solid conclusion, only the sand termite existed under and around every fairy circle examined. Everything else existed only in sections of the entire range of the circles.

“It was very obvious that this same termite was the only one that was always there,” said Juergens. “I´m convinced that must be the organism responsible. The only other alternative is that there´s some type of bacteria or fungus.”

Juergens is not the first to point to termites as the culprit. Others have suggested another species, Hodotermes mossambicus, commonly known as the harvester termite, as the creature responsible for the construction of the circles. However, zoologists quickly dismissed that idea, since the harvester forages over extensive stretches of land.

The sand termite is a much likelier candidate. It lives mainly underground in a network of nests, and are usually only found under their fairy circles. They do not make the obvious mounds seen with other species of termite. During the day, they remain hidden from their nemesis — the meat-eating ants. At night, they rise to the surface to get rid of waste, producing soil dumps that are visible around the outer circles.

Juergens used the soil dumps to measure the density of the termites below. He found that the denser the dumps, the more barren the patch, suggesting that the termites are actively killing the grass within their circles by eating the roots. As they nibble away at the margins, the circles grow. Juergens also found that the soil beneath the circles is extremely humid, suggesting they cultivate the plants to conserve water. They stop the plants from drawing water from the central soils and keep rainwater from rapidly draining into the sand. This explains why the circles only exist in a narrow belt of the desert with very specific environmental conditions: sandy soils and around 4 inches of rain per year.

NOT CONVINCED

Walter Tschinkel, an entomologist from Florida State University, who has studied the fairy circles, is not convinced by Juergens´ findings. He originally suspected termites as the root cause of these patches, but has since recanted.

“As far as I know, termites do not eat live grass,” he told National Geographic. “It is more plausible that the grass died of other causes and was then consumed by termites.”

Tschinkel added that the termite idea also doesn´t explain how termites create the fairy circles´ distinctive patterns, such as their distribution or their changes in size and density across the landscape.

But Juergens explained that termites forage in an extended perimeter beyond the circles, as well as within them. Competition between different colonies can account for the even distribution of the circles. He has even shown that the closer two circles are, the smaller they stay, which he attributes to a sign of fierce competition between neighboring termite colonies.

He further noted that the circles shrink during years with extreme rainfall, since the plants around the borders expand and fill in the barren patches.

“That was a great relief for me,” he said, adding that one of the biggest flaws in his research was that the same termite exists in the eastern parts of Africa that do not have fairy circles. But he explained that the eastern region receives much more rain than the west. In areas with wetter conditions, the termites do not need to rely on engineered circles to retain a supply of water.

LOCAL MYTH

Still, the research will likely not convince the locals who have lived around these fairy circles for centuries.

The Himba people who live in the region tell anthropologists that the circles were made by their “original ancestor, Mukuru,” or more poetically, they are the “footprints of the gods.”

Another tale is that of a mythical dragon that lives in a crack deep underground. The dragon´s poisonous breath kills vegetation to create the circles. However, some scientists point out that the bad-breath hypothesis originated with tour guides, who offered a twist on the popular local legend.

South African scientists have formed their own theory. Working from the University of Pretoria, researchers have tested hypotheses of escaping natural gas like methane or other toxins rising to the surface and killing vegetation at certain spots. But the results of those examinations have been inconclusive.

David P. Crandall, an anthropology professor at Brigham Young University in Utah, has studied the Himba people closely for more than 20 years. He said the local people appear to have little curiosity about why the fairy circles are there, but are concerned because they depend on the grasses around them to graze their cattle, goats and sheep.

Juergens work is detailed in the current issue of the journal Science.


Source: Lawrence LeBlond for redOrbit.com - Your Universe Online



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