RED EARTH CREEK, Alberta — Kristyn Housman grabbed the end of a sampling auger, a steel tube that two colleagues had just drilled into a moss-covered hummock in a peat bog, and poked through a damp, fibrous plug of partly decomposed peat.

Peat has been building up for centuries in this bog, where the spongy moss is interspersed with black spruces and, on a late spring morning, the air is teeming with mosquitoes. The sample, taken from three feet down, is at least several hundred years old, said Ms. Housman, a graduate researcher at McMaster University in Hamilton, Ontario.

“There’s literally tons of carbon here,” she said, looking around the bog, which covers several acres off a muddy oil-company road amid the vast flatness of northern Alberta.

In discussions of how nature regulates carbon dioxide in the atmosphere, forests receive most of the attention for their ability to absorb and store carbon. But peatlands play an important role, too.