19 Jul 34 000 Year Old Termite Mounds
Image: Flowers growing on termite mounds known as heuweltjies (“little hills” in Afrikaans ) in Namaqualand. Credit: Alistair Potts.
Scientists investigating carbon storage and water acidity in the Namaqualand region of South Africa have discovered that some termite mounds in the area are 34 000 years old. Researchers from the South Africa’s Stellenbosch University collaborating with the Institute for Nuclear Research in Hungary were aware that the termite mounds, known in Namaqualand as heuweltjies (“little hills” in Afrikaans), might contain fascinating secrets.
Still, even they were surprised at the results of their radiocarbon dating analysis which revealed that the oldest mounds, which are still inhabited, were built about 29 000 years before the pyramids in Egypt, and were ancient when woolly mammoths ranged across the earth.
It was previously thought that the oldest inhabited mounds, built by a different species of termite in Brazil, were about 4 000 years old.
The lead researcher of the project, Stellenbosch University’s Dr Michele Francis, says that the discovery, in an area about 570 kilometres (347 miles) north of Cape Town, has significant implications for the study of natural methods of carbon sequestration (the process of capturing and storing carbon dioxide from the atmosphere).
“This is more than just an interesting scientific find or historical curiosity” Dr Francis wrote in The Conversation, an online journal written by academics. “It offers a window into what our planet looked like tens of thousands of years ago, providing a living archive of environmental conditions that shaped our world.”
The heuweltjies are built by tiny, about 8 – 15mm long, southern harvester termites which eat grass and other plant material, and the researchers note that this feeding behaviour plays a critical role in carbon storage.
Termite mounds are complex feats of engineering with hundreds of interlinked chambers and tunnels threading through the structure, most of which is underground. (The tall grey or reddish mounds so familiar to many visitors to the bush or rural areas only represent a tiny portion of the entire mound – much as most of an iceberg is unseen below the surface of the sea).
“The insects transport organic material – such as sticks about 2 cm long and a few millimetres wide from woody plants – deep into the soil,” Dr Francis wrote. “This way fresh stores of carbon are continuously added at depths of greater than one metre. Deep storage reduces the likelihood of organic carbon being released into the atmosphere.”
The tunnels built by the termites also allow inorganic carbon, (soil calcite or calcium carbonate) to seep into groundwater. This, and the storage of plant matter, adds to the termite mound’s value as a long-term carbon sink. [1]
