Dan Page
While experts search for ways to cope with excessive
atmospheric carbon, the world's ants may have had a
solution all along.
A new paper reports that ants radically accelerate the
 breakdown of some important minerals into chemicals
 that suck carbon dioxide—a byproduct of burning fossil
 fuels—out of the atmosphere to form new rocks.
Studying the ants could yield valuable clues to scientists
 looking to ward off climate change through carbon
sequestration. Unfortunately, how the ants do it remains
a mystery. Researchers speculate that the mechanism
 may be ant microbes or some function of ant nest-building.
The paper was written by Ronald I. Dorn, a specialist in
rock decay at Arizona State University. Over 25 years,
Mr. Dorn patiently measured mineral breakdown in sand
 by various factors, including ants, termites and bare
ground. Winners by a long shot were the ants, who
were three to 10 times more powerful decay agents
 than tree roots, five times as effective as termites and
 50 to 100 times as effective at dissolving minerals than
adjacent bare soil.
These magnitudes probably underestimate the power
of ants, he writes, because it is unlikely that the ants in
the experiment were in contact with the rock sample for
 every moment of the 25 years. Continuous contact
might produce even faster dissolution.
The effect Mr. Dorn measured was on calcium- and
magnesium-bearing silicates in basalt sand. As these
 dissolve over time, the calcium or magnesium
 released from the minerals combines with carbon
 dioxide from the atmosphere to form calcium
carbonate (limestone) or magnesium carbonate
 (dolomite) layers of rock.
Ants are so effective at promoting this process
that they might have played an unheralded role in
cooling the planet over millions of years, the author
writes, adding that if we can figure out how they do
it, we could investigate how to emulate them to
 sequester atmospheric carbon ourselves.
"Ants as a powerful biotic agent of olivine and 
plagioclase dissolution," Ronald I. Dorn,
 Geology (July 14)