Shawn Fraver
University of Maine, ME·Earth & Environmental Science
Methane is a powerful greenhouse gas that traps 34 times more heat than carbon dioxide. Soil microbes decide whether a forest takes methane out of the air or releases it.
- Fields
Earth & Environmental Science
Ecology & Evolution
Microbiology & Immunology
- Topics
methane
greenhouse gas
methanogens
- Grants
- 1 known grant, last ended Oct 2026
What they work on
- Identify how methanogens (methane-producing microbes) and methanotrophs (methane-consuming microbes) in Howland Forest soils drive methane flux across moisture and other environmental gradients, using microbial community profiling.
- Quantify how wet versus dry microsites, and belowground versus aboveground forest components, contribute to seasonal and yearly methane fluxes, using multi-scale field flux measurements and stable isotopes.
- Test how changing environmental conditions alter microbial methane production and oxidation, using field and laboratory manipulation experiments.
- Integrate field and lab data into the M3D-DAMM and CLM-Microbe process models to project when Howland Forest acts as a methane sink or source from the present to 2100.
More about the research
Microbes in dry soils tend to consume methane, while those in wet soils tend to produce it. At the Howland Research Forest in Maine, measurements since 2012 show that the forest usually acts as a methane "sink" that removes the gas. Under extremely wet conditions, however, it can flip to a source. The region is expected to become warmer and wetter. That raises a question: under what conditions will forests like this switch from removing methane to adding it?
Why it matters
If warmer, wetter northern forests switch from absorbing methane to releasing it, regional and even global atmospheric methane levels could rise. Identifying the conditions and microbes behind that switch could improve climate models used to forecast greenhouse gas budgets. It could also help scientists and land managers anticipate how northeastern forests will respond to climate change through 2100.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Carmella Vizza
Hawaii Pacific University, HI·Earth & Environmental Science
Test whether saltwater introduction lowers methane emissions because sulfate-reducing bacteria outcompete methanogens, comparing freshwater control, saltwater-treated and naturally intertidal ponds in Hawai'i.
Donatella Zona
San Diego State University, CA·Earth & Environmental Science
Extend year-round CO2 and CH4 flux records from five Arctic eddy covariance towers in Alaska to a 20+ year CO2 and 11-year CH4 dataset across moisture and latitude gradients.
Scot Miller
Johns Hopkins University, MD·Earth & Environmental Science·Early-career
Quantify how human-caused methane emissions across the United States, Canada and Mexico changed from 2007 to 2026, combining aircraft, tower and satellite observations with inverse modeling that infers emissions from measured concentrations.
The school
University of Maine: 10 labs on PI Pages, $199M a year on research, 81 research doctorates a year.
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