How the Microbiome of Soil Affects Global Warming

The ground beneath our feet is teeming with microbial life—approximately 10 billion organisms in an average handful of soil. Now, thanks to modern genetic sequencing methods, researchers are getting surprising insights into the vibrant world of dirt.

Next-generation sequencing technologies are beginning to allow researchers to analyze the collective genes, or metagenomes, of these microbial communities. Quanta Magazine has the story of Janet Jansson, division director of Pacific Northwest National Laboratory, and a leader in the effort to characterize the microbiomes of different soil samples. Much of this work seeks to elucidate the role played by microbes in carbon cycling. One finding concerned the largest carbon-storing region of the U.S., the Great Prairie. In samples taken in Iowa, Kansas, and Wisconsin, Jansson and her colleagues found notably different genetic markers in native soil vs. farmed soil. This leads Jansson to hypothesize that carbon cycling may be occurring differently in cultivated vs. wild prairie soil. Meanwhile, samples from the Artic show snapshots of global warming in action: few genes at all in permafrost, suggesting little microbial activitiy; genes for enzymes that break down long carbon molecules (thereby releasing them into the atmosphere) in soil that freezes and thaws; and genes involved in methane production in the warmest Artic samples. Together, these metagenomic analyses show how microbial population may amplify global warming effects as the permafrost thaws, especially by producing the powerful greenhouse gas methane.

If these findings are alarming, the studies also suggest that microbial populations play a key role in carbon cycling, and could be a part of mitigating climate change. For now, though, Jansson remains focused on gathering the massive amounts of genomic information needed for better computational models of these microbiomes. “We’re still at the discovery phase,” she says.

Source: Quanta Magazine