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Wednesday, July 18, 2012

Fairy Circles. Who ya gonna call?

Midsummer Eve (1908) by pre-Raphaelite artist Edward Robert Hughes

A scientist!  A mystery is afoot, quite literally.  You may have read about it in the New York Times Science section recently – Namibian “Fairy Circles,” From Start to Finish.  Biologist Walter Tschinkel of Florida State University recently wrote a fascinating paper about the “life cycle” of strange spots that appear and eventually disappear on the surface of the Namibian desert.  He offers no explanation for the formation of these fairy circles but does debunk a few prior hypotheses including hydrocarbon seeps, termite colonies, or self-organized landscape features.

Namibian fairy circle (photo by Walter Tschinkel)

Tschinkel's paper did not consider the possibility that these circles could be caused by fungi, the cause of fairy rings seen elsewhere in the world (pic below)….maybe you’ve been lucky enough to see one?  A really nice history of fairy rings, and how they can kill local vegetation, can be found on Wikipedia.

However, the mystery deepens with the “heuweltjies”, or “little hills”, of South Africa, located just south of Namibia.  We would drive for hours in South Africa through the polka-dotted landscape of the heuweltjies but, unlike further to the north, they are not flat but are mounds.  The accepted wisdom is that these are fossil termite mounds but I am skeptical, especially after reading Tschinkel’s study.  However, I also can’t imagine how fungi could build such large mounds.  I sampled sediment in and outside of the heuweltjies but when I realized I couldn't bring soil samples back to the U.S. I left the bags with a Cape Town graduate student, Eugene, in hopes that he'd be inspired to investigate further.  Mystery beckons, scientific glory awaits!

Heuweltjies north of Cape Town

More heuweltjies (look in middle distance)