High altitude peatlands in Wyoming's mountains have been shown to sequester large amounts of carbon. Peatlands are a type of wetland also known as bogs, fens, and mires. The name refers to both the peat soil and the wetland habitat on the surface.
Their unique communities of plants and microbes and the high water tables that keep the area mostly submerged and reduce microbial decomposition are why they're so good at storing carbon. According to a new study, that isn't too unique, as most peatlands between 38 to 45 degrees N latitude are important carbon sinks as they absorb more carbon from the atmosphere than they're adding.
"In this area where we have very low decomposition by the microorganisms, the fungi, and the archaea and the bacteria. At the same time, you have a bit of exceeded biological production, so you have peatland vegetation, sedges and mostly sphagnum, that just keeps accumulating but not quite decomposing, you have this huge buildup of carbon." said James Seward, a Ph.D. candidate at Laurentian University in Ontario, Canada, who studies peatland microbial communities. "And they really should be brought more to the table when we're talking about the global carbon budget and things like that."
But as global temperatures increase, peatlands could ramp up production. Plants like sphagnum moss, a type of moss that's unique to peatlands and helps create the acidic environment, will likely spread while water levels fall. This creates an influx of oxygen that will push microbes that previously had little access to it into high gear. Combined with warmer temperatures that increase their productivity as they decompose plant matter, they'll instead become carbon sources, emitting high levels in the form of the greenhouse gases carbon dioxide and methane.
"But one interesting thing that we looked at was the peatlands that were in the Appalachian Mountains, which, of course, are going to be higher in altitude, that's really only the place where they can persist that far south is in the mountains because it kind of presents a haven almost for those pockets. Depending on where you are, altitude can have a great impact on peatland formation," said Seward.
The cooler temperatures of mountains could offer a temporary refuge for peatlands, especially if they're able to migrate up the slopes.
Not only will climate change increase temperatures beyond the ideal range for peatlands, but it will also increase the frequency of threats like droughts and wildfires. If peatlands burn, they release that massive amount of stored carbon into the atmosphere.
But while their biggest threat is climate change, they also face other human-caused challenges.
"There's tons of different aspects that go into it from a climate change perspective, from what I think is direct anthropogenic causes like agriculture and draining [to] maybe something that's more of an indirect, which is something like mining. Tons of sulfur and heavy metals in the atmosphere that kind of pollutes these environments can disturb the vegetation and things like that," said Seward.
Changes to peatlands could create a self-perpetuating cycle where hotter temperatures cause peatlands to emit more carbon, leading to more greenhouse gasses and higher temperatures. According to Seward, the best way to prevent this from happening is to get a handle on climate change before they change roles.
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