Peat bogs sequester a massive amount of the Earth’s carbon dioxide. But even as scientists work to better understand bogs’ sequestration, the wetlands are under threat.
On a cold winter afternoon, naturalist and educator Mary Colwell guided visitors on a chilly tour of the Volo Bog Natural Area in northern Illinois.
Crouching down from a boardwalk that runs through the wetland, Colwell pointed to one of the stars of the tour: sphagnum moss. With her encouragement, the group touched the little branch-like leaves of the pale green moss growing at the base of a nearby tree.
“Then in warmer weather, this is so soft,” Colwell said. “It’s unreal.”
Bog ecosystems are some of the most efficient carbon-storage ecosystems in the world. They cover just 3 percent of the earth’s surface, yet hold up to 30 percent of global carbon.
The bog’s keystone species, sphagnum moss, plays a key role in its storage capacity. Sphagnum acts like a sponge — it holds up to 20 times its weight in water.
“Sphagnum moss itself is incredible,” Colwell noted. “It’s very slow growing.”
It grows so slowly, in fact, that it can take thousands and thousands of years for a peat bog to develop. Volo Bog started to form from a glacial lake more than 6,000 years ago. It’s still encroaching on the center of the lake, called the “eye” of Volo Bog.
But while bog ecosystems provide habitat, filter water, and store carbon, they have been disappearing for decades. In Illinois alone, more than 90 percent of wetlands have been lost. There are about 110 million acres in the United States, with more than half in Alaska — but nearly 70 percent have been drained and developed over the past 100 years.
Unlocking sphagnum moss’s secrets
Scientists think sphagnum moss may hold important lessons about carbon dioxide sequestration, but there’s much they don’t know.
Sona Pandey is the principal researcher at the Danforth Plant Science Center in the St. Louis suburbs, and is part of a team researching sequestration and bogs.
Jess Savage / WNIJ
“The first time I saw a peat moss under the microscope I just literally fell in love with it,” Pandey said. “That’s the only way to describe it. It’s beautiful to look at.”
Pandey’s research team is growing moss in a lab, studying its DNA, and trying to figure out how it is threatened by climate change — and how it could be a solution.
Moss excels at storing carbon. It thrives in waterlogged, acidic conditions. It doesn’t decompose, acting almost like a giant mat of living carbon.
But when it’s threatened, that carbon has to go somewhere. The main threat to bogs — draining for development and agriculture — exposes these waterlogged species to air, which kickstarts the decomposition process from microbes.
“It is a possibility that all the carbon which is stored in peat bogs at the moment will be released to the atmosphere,” Pandey said, noting how it will become a greenhouse gas.
She said if we understand these mosses on a microscopic level, scientists and conservationists can better protect and restore them on a larger scale. Her research could lead to making informed decisions about which species would be more successful to reintroduce as part of potential restoration projects.
Protecting what’s left
Historically, bogs have been undervalued, often drained to make land more usable.
Trisha Atwood, an associate professor and ecosystem ecologist at Utah State University, said people are slowly beginning to see them in a new light.
“There have been substantial changes in people’s perception of these wetlands just because they don’t typically hit people’s Top 10 Most Beautiful Places,” Atwood said. “Governments are starting to realize that they have these other benefits.”
Jess Savage / WNIJ
While forests and forest soil often get attention for their carbon sequestration, Atwood said wetlands are even more important, storing 30 to 50 times faster and at a higher rate than other systems.
“They’re like no other ecosystem on Earth,” she said.
Even as some aspects of wetlands are seen as more valuable, a 2023 Supreme Court decision rolled back most existing protections for these ecosystems. The Sackett v. EPA decision ruled that the Clean Water Act doesn’t protect wetlands that aren’t continuously connected to bigger bodies of water. The decision has been criticized for putting ecosystems like bogs at risk.
Rebecca Hammer is an attorney for the freshwater ecosystems team at the Natural Resources Defense Council, an environmental advocacy group. She said peat bogs are particularly affected by the Sackett decision because they are mostly isolated from larger bodies of water.
“They generally begin their life as a lake that doesn’t have a drainage or connection to another water body, which allows vegetation and plant material to collect,” she said, “and the sphagnum mosses that grow there to collect over thousands of years.”
About half of U.S. states have existing legal protections for wetlands, but these ecosystems in 24 states are left without any protections, legal or otherwise.
There are bogs scattered throughout the Mississippi River basin all the way down to the coast.
Hammer said the decision could have a near-permanent effect on bogs.
“When peat bogs are destroyed or polluted, affected by development, we lose all of those benefits,” she said. “We really can’t replicate peat bogs. They take thousands of years to form. So once they’re gone, they’re gone.”
Colwell, who takes visitors on tours at the Volo Bog, says more needs to be done to protect what’s left.
“We’re trying to restore these natural systems,” she said, “and when we restore them, they can increase the amount of CO2 that they will take.”
This story is a product of the Mississippi River Basin Ag & Water Desk, an independent reporting network based at the University of Missouri, in partnership with Harvest Public Media, a collaboration of public media newsrooms in the Midwest.
