View Other Topics

Scientists Used A Legendary Codebreaker’s Theory To Solve The Mystery Of Namibia’s Desert Circles

Mar 13, 2021

Image: Alan Turning, cryptoanalyst of the Enigma Machine -
There’s a desert that stretches along the Atlantic coast of Africa and is considered one of the driest places in the world. Strange plants grow there that can’t be found anywhere else, but even stranger are the places where the grass disappears. Barren rings, like craters on the moon, have earned the name “fairy circles” because they’re so mysterious. Except their origins may now be explained by the decades old work of a World War II codebreaker.
The Namib desert spans over 1,000 miles across South Africa, Namibia and Angola. And across its length there are millions of the so-called fairy circles that have been baffling scientists for years. The smallest of them is around 6 feet across whilst the largest can be over 100 feet, with each marking a ring in the dry expanse of grass that surrounds them.
But it’s not just Africa that sees fairy circles – with similar phenomena observed in the grassland deserts of western Australia. But it was the Namib where they were spotted first, with Namibia itself being the heartland. There aren’t many humans living in the area, although the Himba people have been observing the circles for centuries.
Studies of the circles really kicked off in the 1970s, but even scientific advances couldn’t offer a definitive explanation. The grass grows normally until it forms a ring around a patch of barren earth, and until now there seemed to be no known reason why. How could these circles be so evenly spread, and so close in size?
Mathematician Corina Tarnita described the circles as looking like a “polka dot dress” as she became one of the many researchers trying to figure out just how these spots came into being. Old legends such as them being a god’s footprint, or wilder new theories that UFOs were involved, probably weren’t the best place to start.
Yet calling them fairy circles does suggest something of a supernatural origin. It recalls the fairy rings of Europe, which are circles of mushrooms long associated with elves, witches or even the devil. Local folklore comes with stories of fairies dancing to create fairy rings, but that’s obviously not the scientific explanation.
So what theories have been suggested on the origin of Namibia’s fairy circles? Well, there have been a few, with varying degrees of evidence to support them. One of the most popular was the idea that they were caused by the insects that live under the desert’s arid surface. The circles formed a kind of “no man’s land” protecting one termite colony from another. Wow, if indeed true.
Termites are known for living in colonies in a similar system to ants. They have a king and queen who rule over an army of soldiers and workers. And they’re found all around the world, from North America to Mediterranean Europe to the easternmost parts of Asia. Some species are also found in southern Africa and Australia, where the fairy circles are.
When termites burrow into the earth to look for food, they dig extensive networks of tunnels. These can destroy any vegetation above the ground without it being obvious that the termites are even there. And the trouble comes when one colony digs all the way to another’s territory, because termites don’t like to share.
If fighting breaks out between two termite colonies, then it won’t end until one of them has been wiped out. That means it makes sense to have buffer zones to stop the groups colliding. In terms of fairy circles, this would mean that the patches of bare earth sit above the termites’ homes, whilst the normal desert “rings” around them are a protective barrier to prevent war.
Termites would also have an impact on how much water was under the soil, which in turn would affect plant growth. That brings us to the other major theory about fairy circles, which is all about water levels. Because there’s not a lot to drink in the dust of the Namib desert, so there’s a lot of fighting over resources.
One patch of vegetation may start to grow, which at first seems like a good thing for the surrounding plants. Because it means there’s shade to cover that patch of earth, and water can start to collect on the surface. But the problem comes when this closely knit area of vegetation starts to expand its roots further out into the desert in the never-ending quest for water.
As the roots grow longer they draw in water from a wider area, which means leaving even drier patches behind them. So plants on the outskirts of the growing vegetation begin to wilt and leave behind the dead areas we know as fairy circles. The competition for water means that even as some living things thrive, others will die.
There is a third theory about the fairy circles, though it’s not quite as well studied as the first two. It involves a shrub called Euphorbia, or spurge, which grows in the desert and is known to be particularly toxic. There’s no conclusive evidence over whether it’s involved in fairy circles, but it is certain that it can be found in the same places the circles appear.
You might be familiar with the type of Euphorbia known as poinsettia, which is often associated with Christmas. The Euphorbia in the desert look a bit closer to cacti, but most interesting of all is how they’re sometimes found even in the otherwise barren ground of the fairy circles. Does their toxicity chase away other forms of life?
All these theories – offering no conclusive proof – meant the scientists were going to have to find new ways to look at the evidence. Except now it seems that the answer may lie in research from decades ago. Because brilliant British mathematician and computer scientist Alan Turing may have found the solution before today’s researchers even started looking.
Qualcomm's Snapdragon 888 promises faster speeds, better cameras and powerful AI. Here are all of the details for Qualcomm's new flagship processor.
Turing died in 1954 when he was only 41, but he’d had an incredible impact on the world. He’s most famous for his work during WWII, when he helped mastermind the decryption of German codes. He even helped pioneer what would become “artificial intelligence.” So some people consider him the father of modern computer science.
During WWII German U-Boats were patrolling the Atlantic with a hunger to destroy Allied ships. Britain desperately needed supplies for its war effort and particularly to help prepare for the D-Day landings. If the cargo on those ships didn’t arrive, then it was going to be very hard to liberate Europe.
The Allies needed to know where the German subs were, so they could plan routes to avoid them. This meant they needed to decode German deployment orders, but these were encrypted using the legendary Enigma machine. It was thought that codes created by Enigma could never be broken. Enter Turing.
Because even before the war Turing had been making waves in the rapidly developing world of computing. His precocity started early, when his teachers expressed concern that he was too interested in science and didn’t pay enough attention to his Latin or Greek. His parents had left him with fosterers shortly after his birth in 1912, so his childhood was lonely but independent.
Turing graduated from Cambridge with first class honors in 1934 before completing a doctorate at Princeton in 1938. During this time he also wrote a ground-breaking paper that would help inspire the development of digital computers. When the war began in 1939, he took his genius to Bletchley Park, home of the Government Code and Cypher School.
On an estate just north of London, codebreakers sat in little huts trying to fathom the mysterious workings of the Enigma Machine. Because its keyboard and rotors had produced 159 quintillion different codes that needed to be deciphered. But the brilliant mathematicians of Bletchley, including Turing, managed to mimic Enigma’s workings and in so doing broke the uncrackable codes.
Yet Turing’s work didn’t stop there. In 1942 he travelled to America to help encrypt discussions between President Roosevelt and British Prime Minister Winston Churchill. And by the end of the war in 1945, he had done enough that he would be awarded the title Officer of the Order of the British Empire, or OBE.
Still, Turing continued to make breakthroughs in computer science after the war, as well as exploring his interest in biology. But Turing was gay at a time when homosexuality was illegal in Britain, and this led to his persecution by the authorities. So it would be many years before his genius could be truly acknowledged.
Now it seems there is yet another way that Alan Turing has changed our understanding of the world. Because the scientists studying the fairy circles of Namibia and Australia have found a way to use Turing’s research to shine new light on the mysterious phenomenon. So there may be explanations for the long unanswered questions.
The theory that the scientists have applied is called the Turing mechanism or Turing pattern. And this is about how spots and stripes can appear in nature when two different substances interact. It’s part of a biological process that’s known as morphogenesis, which is how living things develop their shape.
In the case of fairy circles, it would mean that the uniform growth of desert grasses is predictably disturbed by outside forces (like a lack of water) to form distinct patterns. The relationship of rain, heat and evaporation and their impact on the soil could explain the development of the circles. But first the scientists needed solid proof.
So the German Research Foundation supported a joint investigation that involved ecologists from the University of Göttingen and Helmholtz Centre for Environmental Research as well as scientists from Australia and Israel. The researchers journeyed out into the desert with monitors and drones ready to test their theory.
And they had to drag all 175 pounds of equipment over 700 miles to reach the remote outpost of Newman, Australia. There they set up a weather-monitoring station, launched drones and cameras to view the circles from above and started monitoring the soil. They also dug 154 holes to help measure termite presence in 48 of the fairy circles.
The researchers found there were some gaps in the plants that corresponded to the presence of termites, interestingly. But these were “half the size of the fairy circles and less ordered” according to the author of the study, Stephan Getzin. Other areas of Australia with termites, likewise, didn’t seem to have enough to stop the grass from growing, they said.
That meant that the interaction of plants and soil with some assistance from the weather became the most likely explanation. The Australian soil is heavily clay-based whilst the grasses are from a genus known as Trioda. And when the soil is covered with plants, it tends to be much cooler than the bare patches of the fairy circles, even in the extreme afternoon heat.
The monitoring revealed that when the rain came to the desert, it was in short but heavy bursts. These were enough to turn any sandier patches of soil into silt, with the clay acting as a seal creating a crust over the surface. And this protective layer would stop any further rain penetration, with the water instead forced to run off to the areas outside of the circles.
This means the gaps between the circles are actually an example of “grasses actively engineering their own environment” to make the best use of the little water available. So leaving barren spaces means the spots where plants do grow have additional resources to help them cope in the dry environment.
Everything about the shape and pattern of fairy circles is designed to maximize the efficiency of the vegetation growing there. And a circular shape allows as many plants as possible to make the best use of the available space, whilst also taking advantage of the gaps between them.
Meanwhile, the temperature variations in the soil mean it’s easier for seeds to germinate and grow there. It can reach 167 °F on the surface of the barren fairy circles and that’s hot enough to fry an egg, let alone a plant. But having things a little cooler when there’s vegetation above – such as the grass circles in this case – gives new life a fighting chance.
And a helpful coincidence helped to show the scientists just how natural the development of fairy circles could be. There was a wildfire in that part of the desert whilst the researchers were hard at work, and it destroyed most of the local grass. When it began to regrow, it did so in exactly the same patterns as before.
This was incredibly exciting for Getzin and his colleagues. It showed that Turing’s theories around patterns in nature weren’t just theories but could be applied in the real world. As Getzin himself said, “We could show for the first time with many and very detailed field investigations that Turing’s theory and all the assumptions in the model/theory are indeed met in nature.”
It’s not the complete end of the termite theory of the fairy circles, though. Because Princeton University’s Corina Tarnita has previously worked with colleagues on computer models to test the different explanations for the phenomena. And they managed to predict the presence of fairy circles based on the competition between termite colonies.
Plus they found that smaller rings between the larger fairy circles were predicted by their computer model for competition over water resources. So both termites and water competition seemed to exist and partially explain the appearance of these sections of desert. But there’s some disagreement over whether termites are present at all the sites, and Getzin still believes the insects can’t explain the circles.
Image: Edwin Remsberg/VWPics/Universal Images Group via Getty Images
So Getzin’s next step is to test whether the Turing pattern applies in Namibia as well as it does in Australia. The soil is slightly different in the Namib, without the same density of clay. Thus sandier soil will likely change how the circles develop, according to Getzin’s theory. But he still thinks that “competition of grasses” – in their search for water – will be a key part of the explanation.

Share This Blog with Friends!

  • Starz Radio
  • Blog
  • Yahoo!
  • Google Groups
  • Starz Youtube