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Tuesday, July 17, 2012

Mysterious Circle of African

Mysterious bare spots called 
"fairy circles" dotting the sandy 
desert grasslands of Nambia have 
long stumped scientists who have no 
idea how the strange patterns form.  
(Picture from: http://www.livescience.com/)
Empty circles that dot the prairie Namibia in southern Africa is very similar to polka dot pattern. Mysterious empty circle known as the "fairy circles" will be formed and disappeared a few years later with no known cause.

A recent observation of a number of American researchers of this curious pattern but could not solve the mystery. At the very least, this study reveals that the largest circle can survive in the longer term. Little fairy circles, for example, can last about 24 years, while the larger circle can be aged up to 75 years.

Research results are reported in the journal PLoS ONE, the end of last June 2012. However, the study reveals how little circle was formed and survive in the sandy grassland until then disappeared a few decades later.

"Questions arise about why the circle is very difficult to answer," said study researcher Walter Tschinkel, a biologist at Florida State University in Tallahassee, United States. "There are many hypotheses proposed, but none that presents convincing evidence."

This fairy circle Tschinkel's attention when he did a safari into the Namib Rand Nature Reserve in the Namib Desert in southwestern Namibia in 2005. That's the first time he saw an empty circle in the middle of the pasture, tens of thousands of circles of red sand contrasting with the surrounding grass.
Strange formations. Fairy circles stand out against the grass after seasonal rains in Namibia's Jagkop region. (Picture from: http://news.sciencemag.org/)
Shortly after the circle was formed, the ring of tall grass around the boundary circle, making the area more noticeable empty.

Only a few researchers who study the fairy ring. Therefore, the circle is located in a remote location, 180 kilometers from the nearest village. Landscape of dry grass that is the land of wandering animals, like leopard, ostrich, and the Springbok-a kind of antelope. "Like a die and go to heaven if you love the beautiful remote desert areas," said Tschinkel.

Initially, the circle marks the suspected Tschinkel subterranean termite eaters nest litter. But the excavations found no evidence of termite mounds under the fairy circle.

Other explanations, such as differences in soil nutrient or weed seed mortality due to toxic vapors from the soil, was also not proven. Until now, says Tschinkel, little is known about the life cycle of the circle.

With the help of wildlife officials in the Namib Desert, as well as a stack of satellite imagery and aerial photography meadow, he attempted to investigate the mystery of the fairy ring. By comparing satellite images from 2004 to 2008, he found that the circle is fairly stable, growing rapidly until it reaches full size so the circle appears.
The smallest are about 2 meters in diameter, while the largest can be almost 12 m across. Eventually, plants move back in, re-colonizing the circles and leaving only slightly indented "ghost circles" behind. (Picture from: http://www.livescience.com/)
The smallest circle diameter of 2 meters, while the largest circle of 12 meters. The wind blew an empty area of ​​the circle, turning sand into a slightly concave. In the end, the grass will grow back over the area to empty, occupied the back loop and leaving a trail of ghost circles are slightly curved.

Assuming that the total number of fairy circles on the plains are relatively fixed, Tschinkel using satellite photos to see how fast it's growing cycle, from birth, growing up, until the grass again. The results are used to formulate a life span of circle. Most of the circle survive 30-60 years.

To find out the lifetime of the fairy circles, Tschinkel support funds raised by the Namib Rand Nature Reserve, which sells sponsorship fairy circle. Sponsored circle was marked with ceramic plates and its GPS coordinates recorded.

During the 10-year sponsorship program, wildlife officials check the status of that circle. Tschinkel found that the age range of these data yield the same fairies circle with satellite imagery.

He also found that the circle was formed only in the sandy soil was rocky. Nor could the circle formed on the moving sand dunes or alluvial fan plains. Therefore, water-borne sand.

A number of experiments Tschinkel and his team are still ongoing, but so far nothing that leads to the formation of the circle origin. Tschinkel suspect that circle is the kind of self-organization of natural vegetation.

"There are several mathematical models based on the idea that plants can attract the necessary resources to them," he said. "This has a positive feedback for plant growth in these locations, but carry a negative effect on the plants at a greater distance."

Computer modeling based on mathematical calculations that can create landscapes that seem to resemble the plains fairy circles in Namibia. But even if a hypothesis is located on the right track, it does not explain how plants create this pattern.

Tschinkel said that this fairy circle there is the possibility remains a puzzle that is not revealed. The reason, few people are interested in learning as well as funds to continue to explore the mysteries of the plains in southern Africa does not exist.

"I'm not too worried that this mystery will be revealed," he said. It also makes the mystery of the fairy circles increasingly tempting. "That's science," Tschinkel said. "If you find the answers ahead of time, it's not fun anymore." *** [LIVESCIENCE | KORAN TEMPO 3928]

Natural Phenomenon That is Not Revealed
Walter Tschinkel not the first researcher who was fascinated by the "magic" fairy circles. Gretel van Rooyen, botanists in Pretoria, South Africa, had already been trying to uncover the mystery behind the empty circle. Even van Rooyen has been examined for 25 years.

But long-term research between the University of Pretoria and the Polytechnic of Namibia, which began in 1978, also failed to reveal the puzzle fairy circles in the Namib Desert. In 2004, the team has crossed out the possibility of termite activity, toxicity of native plants that grow in the area, contamination of radioactive minerals, and ostrich dust bathing.

Soil samples from the circle has also been taken to Pretoria for analysis. "We do all the basic soil test to find nutrients and minerals, but could not find an explanation," said Van Rooyen.

Van Rooyen research would add to the mysterious ring of the desert it is believed to have spiritual powers. Hunter tribes who inhabited the region believe that the circle that marks the graves of their tribal fighters killed in armed conflict with the colonialists.

Fairy circle name used to refer to the circles also is derived from a European folklore of fairy circles. In the story, a fairy circle appears as a fairy, pixie or elf nature arise in the area. In German folklore, fairy circle that is where the witches dance.

In contrast to the desert in Africa, fairy circles that were found in Europe is usually a group of fungi that grow lined up to form a circular dome.

"At this stage, I think we can say that fairies are the best explanation of why the circle was there until we finished the research," said Van Rooyen told the Telegraph. *** [TJANDRA | KORAN TEMPO 3928]
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