Peat moss. Most people think of it as the brownish stuff that gardeners add to potting soil. But to one Duke-led team, peat moss plays a key role in slowing climate change by keeping 370 million metric tons of carbon dioxide a year out of the atmosphere — equivalent to the emissions spewed by nearly half the car traffic in the U.S.
Now, thanks to a three-year, $3.1 million grant from the U.S. Department of Energy, the researchers are poised to better understand how global warming could affect peatlands and their vast carbon stores in the future.
Though peatlands cover just 3% of the Earth’s surface — mostly in boreal regions such as Canada, northern Europe and Russia — they store twice as much carbon as all the world’s forests. Over hundreds or thousands of years, sphagnum moss and other peatland plants quietly pull carbon out of the air as they grow, trapping the carbon inside layers of partially decayed plant material up to 20 feet deep.
But warming trends could put that carbon storage at risk. Rising temperatures could thaw or dry out peat wetlands, making them more prone to decay and wildfires. Decomposing or burning plants means the heat-trapping gas long locked up in peatlands could be released, accelerating the global warming process.
To better predict the impacts of warming on peatlands and the carbon they contain, the team is studying a set of players they say are largely overlooked: microbes.
Their previous work suggests that under future warming, the community of microbes and other tiny organisms that grow in and around peat mosses could get out of balance, which could affect the ability of peatlands to sequester carbon.
The leader of the project, which spans three institutions, is Jean Philippe Gibert, a food web expert and assistant professor of biology at Duke.
Alongside a team of co-investigators including Jonathan Shaw of Duke, David Weston and Dale Pelletier of Oak Ridge National Laboratory, and Steven Wilhelm of the University of Tennessee, the team will study and model the effects of warming on the complex network of bacteria, protists and viruses that interact with peat moss.
Ultimately, they hope to show how these interactions might collectively influence the cycling of nutrients such as nitrogen and carbon across different peatland sites.
Understanding these interactions “is central to our ability to predict whether warming will beget further warming, through positive feedbacks on bacterial communities that release CO2, or whether warming impacts will be less important than we currently think,” Gibert said.
The project is one of 25 selected nationwide. “This research will address questions on the neglected components of global carbon cycling, and, as such, is crucial to our efforts to predict global impacts of climate change and propose new ways to mitigate such impacts,” Gibert said.