Oak Ridge National Laboratory of Tennessee has developed a model to get a better measurement of how soil releases carbon dioxide, by tracking microbial processes in the ground.
The carbon cycle with soil starts with a decaying plant in the soil, or carbon rich materials from an animal.
The organic material is degraded by enzymatic reactions (decomposing). This releases carbon molecules which are absorbed by microbes for growth or metabolism, and eventually releasing carbon dioxide into the atmosphere.
The carbon can end up being stored in the soil or released, depending on how fast the decomposition takes place.
Scientists think that if the temperature goes up, the ability of microbes to decompose carbon chains will change, and models need to reflect this.
It has also published a paper in Ecological Applications, the journal of the Ecological Society of America.
“Soil is a big reservoir of carbon,” says Melanie Mayes, co-author of the paper, who works at ORNL’s Environmental Sciences Division.
“Most of the soil carbon cycling models in use today are so vastly simplified that they ignore the fact that decomposition is actually performed by microbes.”
The laboratory developed a model it calls “Microbial-Enzyme-mediated Decomposition” or MEND.
It measures how different types of carbon in soil react with extracellular enzymes excreted into the soil by microbes.
For the next six to eight months, ORNL’s team will run laboratory-scale experiments to ensure that the MEND model accurately represents the decomposition of carbon compounds in soils.
Eventually, team members hope to incorporate their model into the publicly available supercomputing program called the Community Land Model, a module used in the Community Earth System Model that helps researchers predict future climate change.