On a cloudless September morning in Buffelsrivier, a desolate nook of Namaqualand some 530km (329 miles) north of Cape City, Stellenbosch College soil scientists Cathy Clarke and Michele Francis watch as an enormous Volvo excavator tears into the dry ochre earth. Over the subsequent 5 hours the excavator works exhausting to dig a trench, 60m (197 toes) lengthy and 3m (10 toes) deep, via the guts of an enormous, low-slung mound identified regionally as a heuweltjie or “little hill”. It’s all a part of a college undertaking to know why the groundwater within the space is so salty.
As soon as the digger has returned to the close by city of Springbok, inhabitants 12,790, Clarke, Francis, and a bevvy of grad college students start to discover the ditch. They begin at its extremities, what Francis describes because the “boring bits”, feeling the soil and on the lookout for indicators of life. As they transfer inwards, they begin to discover small conglomerations of bewildered southern harvester termites (Microhodotermes viator) furiously making an attempt to restore the harm performed to their house.
On the centre of the ditch, two metres (6.6 toes) beneath floor degree, they encounter “this enormous nest that appears like an enormous alien”, Francis tells Al Jazeera. Clarke nods in settlement: “The second I noticed it I knew we have been witnessing one thing particular. It was simply so clearly historic … And alive.”
As soon as they’d taken a while to easily marvel on the work achieved by these 1cm (0.4 inch)-long creatures, they moved on to the enterprise at hand: taking soil samples. “I delegated the duty to a younger male pupil with a pickaxe,” laughs Clarke. “However he couldn’t get the metal blade to penetrate the edges of the ditch.” The bottom was so exhausting, in line with John Midgley – an entomologist on the KwaZulu-Natal Museum who was not concerned within the undertaking – as a result of it was a part of an “historic mound” created by termites over 1000’s of years. Ultimately, after a lot of huffing and puffing, the grad pupil was capable of get hold of a pattern the dimensions of a soccer ball, which was despatched for testing.
This sort of problem is all in a day’s work for soil scientists, says Clarke, who describes her self-discipline as “a enjoyable mixture of every little thing from bucket science to excessive precision X-ray methods”.
Francis tells me that after they received again to their resort in Springbok on the finish of the day, the cleaner reported them to the supervisor: “She thought we have been zama zamas [South African slang for illegal miners] as a result of our rooms have been coated in orange mud,” she says, including, “I suppose she [the cleaner] had a degree.”
How previous is previous?
The soil scientists knew instinctively that that they had dug up a really previous termite nest. However neither of them was ready for fairly how previous it might be. They submitted samples for radiocarbon courting from the nests and soils from places throughout the enormous mound. These exams analysed the soil natural carbon (decomposed natural matter dragged into the nests by termites) and the soil mineral calcite (inorganic carbon within the type of calcium carbonate) to offer a whole image of the mound’s age.
The exams confirmed that the natural matter dragged into the nest by the termites had been there for at the very least 19,000 years. The mineral calcite within the nests, additionally a results of termite exercise, was even older: It had been round for 34,000 years, since earlier than the final Ice Age.
Francis is fast to level out that “this doesn’t imply the termites have been residing in ice”. As she explains, in arid elements of the world, the Ice Ages have been really a time of a lot: “The Namaqualand obtained considerable rainfall and was a magnet for animals of every type.”
Whereas the entomologist Midgley has little question that termites have been lively within the space for at the very least 30,000 years (fossilised nests have been first discovered within the space within the Nineteen Thirties), he says there is no such thing as a means of proving that the nest has been frequently inhabited for all of that point. “There’s a excessive density of nests within the space. Recolonization appears inevitable, if not essentially intentional,” explains Midgley.
Both means, analysis by Clarke and Francis shines a light-weight on the function these misunderstood bugs play as ecosystem engineers. At the least 165 termite species, from 54 genera, are present in southern Africa. Though there are giant variations between genera they’re all characterised by a excessive diploma of social organisation, with every species containing a number of distinct “castes”. Relying on their caste – reproductive (king and queen), soldier or employee – termites of the identical species can look and behave fully in a different way.
Southern harvester termites primarily feed on sticks and twigs, which they carry down into their nests: in Afrikaans, they’re known as stokkiesdraers (stick carriers) or houtkappers (woodchoppers). Past these nicknames, most individuals know little or no about them – the truth is, they’re typically confused with ants. The one time termites are sometimes talked about is when farmers moan concerning the destruction they wreak on pastures. Utilizing pesticides to kill termites stays a standard observe.
Termites might have a foul rap, however Clarke’s and Francis’ analysis highlights one of many long-term advantages of their stick-eating. Over millennia their redistribution of natural matter drastically alters the composition of the soil, successfully creating two completely different habitats in the identical biome. Some plant species love the mineral-rich soil of the heuweltjies, whereas different crops have tailored to rising in soil that’s not inhabited by termites.
“The termites are one of many causes for the Namaqualand’s unimaginable biodiversity,” says Clarke. The biome, identified formally because the Succulent Karoo, is taken into account “the world’s most biodiverse desert area“.
However this isn’t the one means they profit the planet.
An unintended discovery
The heuweltjies shaped by southern harvester termites are fairly in contrast to the dramatic pinnacles constructed by different species in Africa, Australia and South America. However this doesn’t make them any much less fascinating. Measuring as much as 40 metres (132 toes) in diameter, these raised mounds containing intricate networks of termite tunnels and nests cowl as much as 27 p.c of the floor space of Namaqualand. Scientists are divided over whether or not the termites really assemble the heuweltjies – however even sceptics admit that the termites play a important function of their formation.
The southern harvester termite has a broad distribution vary, however heuweltjies – that are the results of a buildup of high-quality soil materials, carbon and salts over centuries – solely type in semi-desert areas. The southern harvester termite can also be frequent in and round Stellenbosch (the picturesque Winelands college city, about 50km east of Cape City, the place Clarke is predicated), however the heavy winter rains and dense vegetation stop mound formation. Right here the presence of the termites is highlighted by giant bush clumps within the scrubby fynbos (native vegetation) and in nutrient-rich patches in vineyards and fruit orchards.
Buffelsrivier, which receives round 4 instances much less rain than Stellenbosch, is a unique story. Huge, dense heuweltjies dot the panorama so far as the attention can see. In springtime, they’re particularly straightforward to identify, because the heuweltjies are ringed by halos of flowers.
Clarke and Francis began investigating the Buffelsrivier heuweltjies in a bid to know why the groundwater within the neighborhood was so salty – termites have been solely a sideshow. “The goal was to this point the groundwater,” explains Francis. “Was it very previous? Or was it being recharged each time it rained?”
Whereas courting the water, they needed to date the sediments round it. This course of didn’t simply result in the unintended discovery of some very previous termite nests. It additionally confirmed that the salts and different minerals within the groundwater have been the direct results of termite exercise. When it rains, Francis explains, “the salts constructed up within the mounds over 1000’s of years are flushed into the groundwater system by way of movement paths created by the tunnelling motion of the termites, pushing the dissolved minerals ever deeper.”
An ignored carbon sink
Whereas this supplied a definitive clarification for the area’s hypersaline groundwater, it additionally received the scientists serious about the function termites may play in combating local weather change – one thing which had by no means been thought-about for this species.
By dragging sticks and twigs underground, the termites add contemporary shops of natural carbon to the bottom at depths higher than one metre (three toes). This deep storage of natural carbon, explains Clarke, “reduces the chance of the carbon being launched again into the environment and signifies that the mound acts as a long-term carbon sink”. The continuous harvesting of plant matter additionally will increase the fertility standing of those mounds. Therefore the halos of spring flowers.
However the termites’ powers of sequestration don’t finish there. The organic breakdown of termite excrement (generally known as frass) triggers a cascade of organic reactions, which ends up in the formation of calcium carbonate – the fabric limestone is fabricated from. This calcium carbonate is a really steady type of carbon that’s locked within the soil for 1000’s of years. A few of this carbon leaches into groundwater the place it could stay for hundreds of years.
“That is the type of long-term carbon storage [14.6 metric tonnes] technique that carbon storage firms try to copy,” says Clarke. “However the termites have been doing it for 1000’s of years.
“It’s time we stopped viewing termites as pests and began to see the vital function they’ll play in preventing international heating.”
Midgley, the entomologist, agrees, “Termites are fascinating creatures that promote biodiversity in assorted and surprising methods. For instance, we discovered a species of hoverfly that depends on termite frass as a larval habitat … with out termites, it might go extinct. The extra we discover, the extra fascinating elements of termite life will emerge.”
Clarke and Francis consider that “termite exercise needs to be integrated into carbon fashions”. These fashions at present focus totally on forests and oceans, so “together with termite mounds might assist present a extra complete understanding of world carbon dynamics”.
Solely scratching the floor
Till Clarke’s and Francis’ discovery, the oldest natural matter present in a termite colony got here from a 4000-year-old hen in Brazil. That stated, only a few research have used heavy equipment to penetrate the exhausting crust shaped by the bugs, so there’s an excellent likelihood there might be even older colonies on the market – both in Namaqualand or elsewhere.
Regardless of being a soil scientist and never an entomologist, Francis admits to having fallen for the honey-hued bugs and their complicated societies. “I do know we’re not presupposed to ascribe human qualities to bugs,” she says. “However I can’t assist myself. If I had limitless time and funding, I might like to excavate termite mounds all around the globe.”
For now, nevertheless, she’ll must content material herself with a follow-up undertaking that takes a extra in-depth take a look at the mechanisms of carbon sequestration within the Namaqualand heuweltjies. Stellenbosch College initiated the undertaking, however because of a multinational grant funded by the Nationwide Science Basis (US) and the Nationwide Analysis Basis (South Africa), the undertaking now boasts a workforce of microbiologists, ecologists and geochemists from the US and South African scientists.
Finally, these pint-sized ecosystem engineers are getting the eye they deserve.
