By Kerry Bennett
Office of the Vice President for Research


The Earth’s atmosphere, oceans and biosphere are huge reservoirs of carbon, and all play a critical role in global carbon cycling. Soil is one of the largest carbon pools on the planet, storing more carbon than the atmosphere and biosphere combined, yet scientists aren’t sure what regulates carbon persistence—the amount of carbon that remains in the soil.

Scientists at the Lawrence Livermore National Laboratory (LLNL) believe the soil microbiome—made up of microorganisms such as fungi, bacteria, microfauna and viruses—has a major effect on the size and longevity of the soil carbon pool, affecting soil fertility, its water-holding capacity and the planet’s carbon cycle.

NAU Regents’ Professor Bruce Hungate, director of the Center for Ecosystem Science and Society (Ecoss), recently joined a new initiative lead by LLNL to study how the soil microbiome controls the mechanisms that regulate the stabilization of the organic matter in soil.

“How do different kinds of microorganisms in the soil grow? How do they die and how quickly do they die? What role do viruses, starvation and environmental shocks play in this cycle? Finding the answers to these questions is important because we know that microbes are the main players in how much carbon is stored in the soil,” Hungate said. “The more carbon that’s stored in the soil, the less carbon is released into the atmosphere as carbon dioxide, which causes global warming.”

Funded by the U.S. Department of Energy’s (DOE) Office of Biological and Environmental Research for $2.5 million per year for the next three to five years, the project represents a collaboration between the LLNL team and researchers at the University of California Berkeley, Northern Arizona University and Ohio State University as well as Lawrence Berkeley and Pacific Northwest national laboratories. NAU associate research professor Paul Dijkstra, assistant research professor Christina Schaedel and senior research associate Ben Koch, all with Ecoss, also are involved in the project.

Researchers will use LLNL’s mass spectrometry and isotope tracing tools to trace microbes and their cell materials (necromass) as they become part of the soil environment. NAU collaborators will employ a method developed by Hungate and several co-inventors to quantify Stable Isotope Probing (SIP) data in their microbial ecology samples.

About Ecoss

Ecoss researchers probe the biology, chemistry and geology of the biosphere, bringing tools and perspectives from ecosystem science to the ecology of the integrated earth system. Their work focuses on ecosystems and how they respond to and shape environmental change.