Tuesday, 30 September 2014

Fairy CIrcles in the Namibian desert

It’s not a phenomena you’d expect to encounter in the wilds of Namibia but fairy circles, perfectly circular bare patches in the grassland, have been appearing in certain geophysical places throughout the Namib Naukluft park for years. Some attribute these highly visible bare earth circles to Martians. Others call them Bushmen golf courses. However these odd-looking circles of bare earth are really created by harvester termites nesting underneath the site. The termites create a nest at a shallow depth underneath the surface where they store their food – grasses and other vegetable matter. This is broken down using bacteria that develop from the moisture seeping into the colony. The bacteria, or perhaps the fermentation itself, changes the chemical make up in the nest and this filters into the soil, inhibiting the development of grasses growing on the surface. Hence the curious bald patches that develop on the surface. These can be from about a metre wide up to eight metres. 

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