Scientists to examine origins of soil-carbon chemical chain reactions

Potential connections between the biodiversity of soil microorganisms and the carbon cycle will be studied by the Translational Genomics Research Institute (TGen) and Northern Arizona University (NAU) under a $2 million grant from the National Science Foundation (NSF).

The TGen-NAU project was one of 14 recently awarded a grant by NSF under the Dimensions of Biodiversity program.

"The work will test the idea that biodiversity is a fundamental driver of the carbon cycle, connecting microbes to the entire Earth system," said Dr. Bruce Hungate, Professor of Biology and a Director in NAU's Merriam-Powell Center for Environmental Research.

The project will investigate "a surprising response" to changes in soil carbon levels: When new carbon enters the soil, a chain reaction leads to the breakdown of older soil carbon that otherwise would have remained stable, Dr. Hungate said.

"Current theory does not explain this chain reaction," Dr. Hungate said. "The project will explore new dimensions connecting the diversity of the tree of life with the carbon cycle."

TGen's role in the project leverages advances in metagenomic sequencing - spelling out the DNA code of microbial samples from the environment -made by Dr. Lance Price, Director of TGen's Center for Microbiomics and Human Health, and Dr. Cindy M. Liu, a medical doctor and researcher at both TGen and NAU, who now works for Johns Hopkins University.

"This project is a natural extension of our efforts to understand how the human microbiome responds to injuries, surgeries and chemicals," Dr. Price said. "Here, we're investigating how the planet's microbiome responds to excess carbon inputs, which may in turn loop back to negatively affect public health."

The work is important, Dr. Hungate said, because soil carbon is a major reservoir in the global carbon cycle, storing about three times the amount of carbon contained in the atmosphere as carbon dioxide. Some soil processes promote carbon storage, locking it away in stable forms, resistant to decay.

The phenomenon to be addressed has the opposite effect, converting carbon that was thought to be stable to carbon dioxide, and contributing to the atmospheric pool, amplifying rising carbon dioxide due to human burning of coal, oil and gasoline.

Dr. Hungate's extensive portfolio of research includes the ecosystem effects of biodiversity loss, the effects of climate change on plant growth, and the role of soil microbes in accelerating global warming.

NSF describes its biodiversity program's long-term goals as developing "an integrated understanding of the key dimensions of biodiversity in our ever-changing world."