Fossils Reveal Ancient Carbon Capture Structures
Scientists in South Africa have uncovered the world's oldest termite mounds, which have been storing carbon for millennia.
Using radiocarbon dating, researchers found the mounds along the branches of the Buffels River in Namaqualand—an area along the west coast of South Africa where approximately 20% of the landscape is covered by these structures—to be the oldest known, with some dating back up to 34,000 years.
Purple flowers bloom on top of tens-of-thousands-year-old termite mounds in Namaqualand, South Africa. CREDIT: Jannick Niewoudt and Alastair Potts
According to the study's lead author, Michele Francis of Stellenbosch University, South Africa, the termites, as they forage for food, take bits of wood back into their nests. Over time, this organic material accumulates, creating a massive carbon sink.
In previous research, Francis's team estimated that each mound could store around 14 tons of carbon. For this study, Francis was interested in how the groundwater, air, and soil in these formations interact to "lock in" such a large amount of carbon.
Ancient Carbon Capture Process
Analyzing the chemical makeup of the mounds, the team observed the chemical processes that sequester carbon from the atmosphere in these mounds. The researchers found that the termites' wood-carrying activities help aerate the soil, making it more permeable to water. Bacteria in the soil then convert this stored carbon to calcium carbonate.
During heavy rainfall events, the calcium carbonate in the mounds reacts chemically with carbonic acid and forms carbon dioxide gas that dissolves into the rainwater. This increases the amount of CO2 sequestered from the atmosphere.
Mounds as Climate Change Mitigation Models
This process locks away the new carbon roughly 1 meter below the surface of the mounds for long-term storage, LiveScience reported on June 26.
"By studying these mounds, scientists can gain insights into mitigating climate change, using nature's own processes to sequester carbon. These mounds not only shed light on the past but provide important clues for our future," Francis said.
Summary
Scientists have discovered the world's oldest termite mounds, dating back to 34,000 years ago. These structures have been storing carbon for millennia, and researchers are investigating the chemical processes that make this possible. By studying these ancient carbon capture systems, scientists hope to gain insights into mitigating climate change using nature's own methods.