The world's oldest termite mounds have been found in South Africa, storing carbon for thousands of years

The world's oldest termite mounds have been found in South Africa, storing carbon for thousands of years


For image representation.

Image representation. | Photo Credit: The Hindu

The landscape along the Buffels River in South Africa's Namaqualand region is dotted with thousands of sand dunes, covering an area of ​​some 1,000 square kilometres. 20% of the surface area. in HeuweltjiesAs the locals call them (the word means “little hills” in Afrikaans), the termite mounds contain an underground network of tunnels and nests of the southern harvester termite, Microhodotermes viator,

I am part of a group of Earth scientists who, in 2021, Study Why is the groundwater salty in this area, about 530 km from Cape Town. The salinity of groundwater appears to be related to the location of these places in particular HeuweltjiesWe used radiocarbon dating; we reasoned that dating the mounds would help us see when those minerals were formed The water collected in the dunes was drained into the groundwater,

The tests revealed more than we expected: Namaqualand Heuweltjiesit turns out, The world's oldest inhabited termite moundsSome are from a long time ago Between 34,000 and 13,000 years old.The oldest known inhabited mounds were 4,000 years old (from a different termite species from Brazil) and 2,300 years old (from central Congo)

It's more than just an interesting scientific discovery or historical curiosity. It tells us what our planet looked like thousands of years ago, and provides a living archive of the environmental conditions that shaped our world.

This is still very important today: there is growing evidence that termites have a huge impact, but they still survive. poorly understoodRole in the carbon cycle. By studying these and other termite mounds, scientists can gain a better understanding of how termites sequester (store) carbon. This process removes CO₂ from the atmosphere and is important for mitigating climate change.

Carbon storage

Namaqualand is a global biodiversity hotspot famous for its Spring FlowersBut this is a dry area. Surface water is in short supply and groundwater is saline.

Although most of Namaqualand receives very little rainfall, there are rare, high-intensity rainfall events. When this happens, termite burrows on the surface of the mound act as drainage channels that can collect and transport rainwater into the mound. This reduces water scarcity. salt deposits in dunes Over thousands of years, groundwater has been channeled into the system through flow paths created by the termites' tunneling activity, leaving dissolved minerals permanently locked underground. DeeperThis process also drives down carbon Gradually a construction took place between the dunes When termites collected plant material and placed it into the mound over thousands of years.

The ability of these mounds to absorb carbon is linked to a unique behavior of the termites. organic material – such as small sticks about 2cm long and a few millimetres wide obtained from small woody plants – Deeper into the soil. In this way, new carbon reserves are created Continuously added At depths of more than a metre. Deep storage reduces the chance of organic carbon being released back into the atmosphere. The mound therefore acts as a long-term carbon sink.

Not only do termites carry organic carbon material to their nests deep in the ground, but their tunnels also carry dissolved inorganic carbon in the soil (known as soil calcite or calcium carbonate) to their nests. move to groundwater with other soluble minerals. Hence termite mounds also Proposed a mechanism for separating carbon dioxide By dissolving carbonate-bicarbonates in the soil and releasing them into groundwater. This is a long-term carbon storage method that carbon storage companies are trying to replicate to reduce atmospheric carbon.

Our results from radiocarbon dating of both organic and inorganic carbon in this soil indicate that organic matter and nutrients are accumulating in the mounds. including carbonfor thousands of years. This richness is one reason why Namaqualand's famous wildflowers feature so prominently on the dunes in spring.

During the formation of the dunes, the region experienced more rainfall That's more than today. Studying the layers of the dunes and looking at carbon, sulfur and oxygen isotopes preserved in the dunes and groundwater revealed that periods of higher rainfall in the region were associated with global climate cooling. These cool and wet periods were associated with the seepage of accumulated carbon and other minerals into groundwater.

Little Engineer

These findings are further evidence that termites fully deserve their reputation. Ecosystem EngineerThey modify their soil surroundings to maintain ideal humidity and temperature conditions, and their food-seeking trails extend over several tens of metres.

We argue that, given what we have discovered in Namaqualand, termite activity should be included in carbon models. These focus mainly on forests and oceans; including termite mounds could help provide a more comprehensive understanding of global carbon dynamics. In Namaqualand, mounds occupy only 27% of the total area, but contribute 44% of total soil organic carbon stockThis highlights the disproportionate contribution of termite mounds to carbon storage in these semi-arid environments.

Public awareness and policy integration are also important. Often termite mounds are cleared for agriculture or termite killing is considered. PestsRaising awareness about Ecological Importance of Termite Mounds And integrating these findings into environmental policies can help promote practices that support natural carbon sinks.

This research was carried out by a dedicated team from Stellenbosch University (Department of Soil Science and Earth Sciences), South Africa, in collaboration with experts from the Hungarian Institute for Nuclear Research: C.E. Clarke, M.L. Francis, M. Hatting, J.A. Miller, T. Nel, B.J. Sakala, J. van Gend, N. Vermonti, M. Vermooten (Klein), A. Watson (South Africa), L. Pulshoo, A. Horvath M. Molnar T. Kertesz (Hungary).

This article is republished from The Conversation under a Creative Commons license. Original article,


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