Geology, September 2014, v. 42, p. 771-774, first published on July 14, 2014, doi:10.1130/G35825.1

Ants as a powerful biotic agent of olivine and plagioclase dissolution

Abstract

The biotic enhancement of Ca-Mg silicate weathering has helped maintain Earth’s habitability over geological time scales by assisting in the gradual drawdown of atmospheric CO2. 25 years of in-situ measurements of Ca-Mg silicate mineral dissolution by ants, termites, root mats, bare ground, and a control reveals ants to be one of the most powerful biotic weathering agents yet recognized. Six sites in Arizona and Texas (USA) indicate that eight different ant species enhance mineral dissolution by ∼50×–300× over controls. A comparison of extracted soil at a 50 cm depth in ant colonies and adjacent bare ground shows a gradual accumulation of CaCO3 content for all eight ant species over 25 yr. Ants, thus, have potential to provide clues on how to enhance contemporary carbon sequestration efforts to transform Ca-Mg silicates and CO2 into carbonate. Given that ants underwent a great diversification and biomass expansion over the Cenozoic, a speculative implication of this research is that ant enhancement of Ca-Mg silicate dissolution might have been an influence on Cenozoic cooling.

Michael V said:

Ants as a powerful biotic agent of olivine and plagioclase dissolution

You could not have possibly made that up. I suggest the use of a random word generator?

Michael V said:

Geology, September 2014, v. 42, p. 771-774, first published on July 14, 2014, doi:10.1130/G35825.1

Ants as a powerful biotic agent of olivine and plagioclase dissolution

Abstract

The biotic enhancement of Ca-Mg silicate weathering has helped maintain Earth’s habitability over geological time scales by assisting in the gradual drawdown of atmospheric CO2. 25 years of in-situ measurements of Ca-Mg silicate mineral dissolution by ants, termites, root mats, bare ground, and a control reveals ants to be one of the most powerful biotic weathering agents yet recognized. Six sites in Arizona and Texas (USA) indicate that eight different ant species enhance mineral dissolution by ∼50×–300× over controls. A comparison of extracted soil at a 50 cm depth in ant colonies and adjacent bare ground shows a gradual accumulation of CaCO3 content for all eight ant species over 25 yr. Ants, thus, have potential to provide clues on how to enhance contemporary carbon sequestration efforts to transform Ca-Mg silicates and CO2 into carbonate. Given that ants underwent a great diversification and biomass expansion over the Cenozoic, a speculative implication of this research is that ant enhancement of Ca-Mg silicate dissolution might have been an influence on Cenozoic cooling.

I like this very much. Rates of feldspar weathering have been studied for over a hundred years, so it’s well known which of the Ca-Mg silicates weather fastest and which slowest. It also makes sense that the presence of biological acids such as formic acids from ants could increase this weathering rate enormously. The effects of biology on mineralogy have been studied enough that we now know that a sizeable percentage of all mineral types known (at a wild guess, 30%) have resulted from biological action. But this is the first study I’ve heard of where the effect of animal colonies on mineral weathering has been directly measured. And you’re right, that could have a big influence on CO2 take-up.