Ants As Geochemists

Ants have been known to have a positive impact on soils by mixing different layers and by adding nutrients, etc. Now a researcher from Arizona State University, Dr. Ronald Dorn, has found that ants are enhancing the breakdown of certain minerals and the movement of carbon dioxide into calcium carbonate (limestone). The bottom line:  ants might be helping to remove greenhouse gases from the atmosphere.

Dr. Dorn did not start out to study ants. He actually began the study 25 years ago to look at weathering of olivine and plagioclase minerals from Hawaiian basalt. He placed samples in various sites in Arizona and Texas, and then went back every five years to see what was happening to them.

Other researchers have shown that weathering of calcium and magnesium silicates by living things is important in removing atmospheric carbon dioxide gases. A simplified reaction is shown here:

weathering

Over the 25 year period of this study, Dorn found the ant colonies of eight different ant species (Pogonomyrmex rugosus, Pogonomyrmex barbatus, Dorymyrmex bicolor, Forelius pruinosus, Liometopum luctuosum, Tapinoma sessile, Formica neogagates, and Camponotus vicinus), enhanced the weathering of the minerals some 50x-300x over that of the bare ground control. At the same time he found the percent carbonate increased substantially in the nests of all the different species.

pogo-carrying-dirt-1

Pogonomyrmex worker ant moving soil from its nest.

Of all the factors he studied, Dorn found that ants were by far the most important weathering agents. Given the amount of material a given ant colony moves around, that is not surprising.

What was a bit more surprising was that all the ant nests accumulated calcium carbonate over time, at levels well above what was happening in bare soil nearby. Perhaps it is time to investigate what exactly ants are doing in those underground galleries.

What do you think? Are ants an answer to removing excessive carbon dioxide from the atmosphere?

Dorn, R.I. (July 14, 2014) Ants as a powerful biotic agent of olivine and plagioclase dissolution. Geology.

Interested in learning more about the impact of ants on soils? Try this excerpt from the Encyclopedia of Soil Science Vol. 1