Researchers locate a carbon store six feet below the soil surface

November 26 (UPI) – At least a quarter of all the carbon stored in the Earth's soil is enclosed in minerals about six feet below the surface. But new research suggests that this unique carbon pool will become less efficient in terms of carbon storage as the planet warms up.

To better understand the impact of rising atmospheric carbon dioxide levels on the planet's climate, scientists need to model more precisely the Earth's many carbon cycles. The soil hosts one of these carbon cycles.

As part of a new study, the first of its kind, researchers have detailed how carbon binds physically and chemically to minerals found in soils around the world. The results of the survey were published Monday in the journal Nature Climate Change.

"We know less about the soils of the Earth than about the surface of Mars," said Marc Kramer, associate professor of environmental chemistry at Washington State University in Vancouver, in a press release. "Before we can begin to think about storing carbon in the soil, we really need to understand how it does it and how likely it is to stay in. This discovery highlights a major breakthrough in our understanding."

After analyzing climate data and soil samples collected from 65 different excavation sites in America, New Caledonia, Indonesia and Europe, the researchers created a global map of soil carbon sequestration.

The new data showed that minimal amounts of carbon are stored in desert sediments and dry forests, but that about six feet below the surface of moist forests, scientists have discovered an abundance of carbon-bound minerals reagents.

The persistence of water and decaying organic matter on the forest floor helps to leach carbon from above and to transport to buried minerals underneath.

"This is one of the most persistent mechanisms of our carbon accumulation," said Kramer.

According to the new study, global warming will have no impact on carbon already stored below the surface of moist forest soils, but it will change the way in which new carbon is stored. Increases in temperature will likely minimize the amount of water flowing through the forest floor, even if precipitation remains stable.