How Ants Capture Carbon Dioxide to Create Natural Armor

The remarkable ability of certain ants to convert carbon dioxide from the atmosphere into dolomite stones within their exoskeletons offers potential insights into innovative methods for humans to sequester greenhouse gases and mitigate climate change.

Fungi-farming ants, like Acromyrmex echinathiol, forage for vegetation to nourish the fungi cultivated in their colonies, which serve as their primary food source. High ant and fungal densities can lead to elevated levels of CO2 within their nests.

Research in 2020 by Cameron Currie at the University of Wisconsin-Madison discovered that this species incorporates carbonate biominerals into their exoskeletons through a unique symbiotic relationship with specific bacteria. These bacteria facilitate the conversion of CO2 into rock using a somewhat enigmatic chemical process.

Recently, the research team identified another species, Sericomyrmex amabilis, residing in Central and South America, capable of achieving this remarkable feat without the assistance of symbiotic bacteria. This makes it the first known animal to evolve such an ability.

Interestingly, the mineral produced by these ants is dolomite, which is notoriously challenging for chemists to synthesize in laboratory conditions. The formation of dolomite rocks, such as those in the Italian Dolomites, requires millions of years and intricate geological processes for the calcium and magnesium atoms to align properly. In stark contrast, ants can accomplish this swiftly and effortlessly, according to Li Hongjie from Zhejiang University in China.

Dolomite is a composite of calcium, magnesium, and carbonate. Its laboratory formation is difficult due to magnesium’s strong bonding with surrounding water molecules, which hinders the integration of magnesium into the calcium carbonate structure, as indicated by Currie. Typically, scientists employ high temperatures and pressures to facilitate this process. The next step for researchers is to unravel how these ants master this extraordinary capability.

For fungi-farming ants, the transformation of CO2 into stone not only strengthens their exoskeletons but also neutralizes detrimental CO2 accumulation within their hives.

“We uncovered a natural system that has evolved over millions of years to mitigate the buildup of harmful atmospheric carbon dioxide in ant colonies,” Currie remarked.

In their quest to combat global warming, scientists are investigating techniques to convert atmospheric CO2 into carbonate minerals, essentially solidifying carbon into stone. “These ants represent the first known animals to partake in such processes, providing exciting potential as models for human applications,” asserts Currie.

Cody Freas, a professor at the University of Toulouse in France not involved in the study, hailed the ants’ capability to transform CO2 into dolomite as an “extraordinary adaptation.” “These ants function as living carbon scrubbers, converting atmospheric CO2 into a protective mineral armor. This dual strategy aids them in regulating the nest atmosphere and crafting bioengineered physical defenses,” Freas elaborated.