What is it all about?
In November 2018 a group of international scientists published the results of their research in Brazil. They found a vast array of soil mounds constructed by Syntermes dirus, one of the thousands existing kinds of termites. The scientists claim they found the biggest ecosystem on our planet. Also, they discovered that the oldest mounds are dated about 4000 years ago. These mounds are located in a region of Northeast Brazil, which is climatically stable and relatively undisturbed. The area occupied by termites takes 230,000 km2, which can be compared with the square of Great Britain. A part of these mounds was found on satellites pictures.
What these mounds are?
However, one can think they are nests, it is wrong. Scientists proved the excavation of vast inter-connecting tunnel networks generated the mounds. Unlike other systems, these mounds do not create any surrounding vegetation patterns.
Stephen J. Martin and other scientists studied hundreds of mounds, some of which were destroyed by a road construction. They came to a conclusion that every mound is just a separated mound of the earth without the inner structure. Active mounds, which are just forming, have a single large central tunnel linked with an extensive network of underground tunnels. Moreover, narrow horizontal galleries with harvested disks and dead leaves or brood were discovered.
Numbers to consider:
- The total volume of ground in the mounds – 10 m3, which is equivalent to a few Egyptian pyramids (or 4000 great pyramids of Giza).
- The total number of conical mounds – 200 000 000.
- The mounds are 2.5 m tall.
- The mounds diameter is 9 m.
- Every mound consists of about 50 m3 of the ground.
- The average distance between the soil mounds is 20 m.
- The size of the termites is 1 cm.
A few facts about the termites
S. dirus themselves still can be found in the mounds. The scientists found that intra-specific aggression occurred at a scale much larger than an individual mound. The reason they give to explain such behavior is termites’ aspiration to get an access to leaves that episodically fall. As a result, the termites optimized the waste soil removal by building tunnels. For thousands of years, they did the same, and mounds appeared.
There was a supposal that termites use the tunnels for ventilation, but scientists’ supervision denied it. At night a group of soldiers leaves mounds for foraging. They create temporary tunnels and close them after the usage. Also, it became clear that there is not a room for the queen, but scientists plan to find it. One more fact is that the tunnels help termites to find food occasionally, not in the places of permanent feeding.
The methods used by scientists
To come to all these conclusions scientists had been exploring the ground and the structure of soil mounds. Stephen J. Martin and his team had used single-grain optically stimulated luminescence and the minimum age model, which helped to determine the age of the mounds properly. The images taken from satellites were also studied. These mounds are not so unique
The mounds of the comparable age were found in Africa. Hans Erens and his team published their research in 2015. To estimate the age of the mounds they had used C-dating acid-insoluble organic carbon. They also found that temperature had changed in the researched area.
Adverse environmental conditions made termites to create a new way of finding food. They made tunnels, which helped to find food occasionally and close the tunnels when the goal is achieved. Termites used the land for thousands of years, which led to a vast area of mounds. Now they can be seen from space. Scientists made a conclusion that termites do not live here and did not find a queen. Similar researches are conducted not only in Brazil. Scientists from different countries also study the mounds.