A possible souce for the "fairy circles" in Africa
March 29, 2013 8:56 AM Subscribe
In temperate climates, "fairy rings" appear in grassy meadows and lawns, and these are caused by fungi, with some rings expanding for hundreds of years. But in the western part of Southern Africa, there are a different sort of "fairy circles," barren circles that are surrounded by long-lived perennial grasses. The Himba people, an ethnic group in northern Namibia, attribute them to original ancestor, Mukuru, or consider them "footprints of the gods," and scientists have been stumped for decades. Professor Norbert Jürgens, from the University of Hamburg, might have finally solved the riddle: a species of termites that are most active at night and don't build big, noticeable nests, have engineered the ecosystem by eating the roots of grasses that grow within the circle, keeping the soil moist for long periods of time. The discussion continues, as some scientists who have studied the phenomena aren't so sure about the theory.
From the African "fairy circles" link (Wikipedia):
Dispelled in turn were radioactive soil, soil poisoned by the milk bush (Euphorbia sp.) and termite activity. As part of the project, pots with soil and grass from outside the circles were planted in the circles. Half of the pots were sealed at the bottom. Only the grass in these sealed pots survived. It was speculated that rising gas may be responsible for the deaths, leading to the involvement of the University's chemistry department. It was then shown that oxygen levels had been depleted within the circles. Setting up gas measuring instruments, the team found that there were intermittent releases of carbon monoxide inside the circles, stunting root development. The source and mechanism of these releases is still under investigation.
That seems to be an alternative to termites, no?
posted by A dead Quaker at 1:03 PM on March 29, 2013
Dispelled in turn were radioactive soil, soil poisoned by the milk bush (Euphorbia sp.) and termite activity. As part of the project, pots with soil and grass from outside the circles were planted in the circles. Half of the pots were sealed at the bottom. Only the grass in these sealed pots survived. It was speculated that rising gas may be responsible for the deaths, leading to the involvement of the University's chemistry department. It was then shown that oxygen levels had been depleted within the circles. Setting up gas measuring instruments, the team found that there were intermittent releases of carbon monoxide inside the circles, stunting root development. The source and mechanism of these releases is still under investigation.
That seems to be an alternative to termites, no?
posted by A dead Quaker at 1:03 PM on March 29, 2013
You are correct, and as noted in the last link in the OP, some scientists who have studied the circles in the past aren't completely satisfied with the current termite theory.
posted by filthy light thief at 1:39 PM on March 29, 2013
posted by filthy light thief at 1:39 PM on March 29, 2013
What's the word for physical graffiti? Littering doesn't seem to apply.
posted by Mitheral at 1:57 AM on March 30, 2013
posted by Mitheral at 1:57 AM on March 30, 2013
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Also, who at "Wired" looked at that picture and decided that "inexplicable geometric precision" was the caption it needed? It certainly sounds more evocative than "sort of blobby roundish patches" but the later is more accurate.
posted by Kid Charlemagne at 9:09 AM on March 29, 2013