title: Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands.
abstract: Permafrost peatlands store one-third of the total carbon (C) in the atmosphere and are increasingly vulnerable to thaw as high-latitude temperatures warm. Large uncertainties remain about C dynamics following permafrost thaw in boreal peatlands. We used a chronosequence approach to measure C stocks in forested permafrost plateaus (forest) and thawed permafrost bogs, ranging in thaw age from young (<10 years) to old (>100 years) from two interior Alaska chronosequences. Permafrost originally aggraded simultaneously with peat accumulation (syngenetic permafrost) at both sites. We found that upon thaw, C loss of the forest peat C is equivalent to ~30% of the initial forest C stock and is directly proportional to the prethaw C stocks. Our model results indicate that permafrost thaw turned these peatlands into net C sources to the atmosphere for a decade following thaw, after which post-thaw bog peat accumulation returned sites to net C sinks. It can take multiple centuries to millennia for a site to recover its prethaw C stocks; the amount of time needed for them to regain their prethaw C stocks is governed by the amount of C that accumulated prior to thaw. Consequently, these findings show that older peatlands will take longer to recover prethaw C stocks, whereas younger peatlands will exceed prethaw stocks in a matter of centuries. We conclude that the loss of sporadic and discontinuous permafrost by 2100 could result in a loss of up to 24 Pg of deep C from permafrost peatlands.
authors.affiliation: U.S. Geological Survey, Reston, VA, 20192, USA.
authors.forename: Miriam C
authors.initials: MC
authors.lastname: Jones
authors.affiliation: U.S. Geological Survey, Menlo Park, CA, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Harden
authors.affiliation: National Park Service, Anchorage, AK, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: O'Donnell
authors.affiliation: U.S. Geological Survey, Menlo Park, CA, USA.
authors.forename: Kristen
authors.initials: K
authors.lastname: Manies
authors.affiliation: Ecoscience, Fairbanks, AK, USA.
authors.forename: Torre
authors.initials: T
authors.lastname: Jorgenson
authors.affiliation: U.S. Geological Survey, Menlo Park, CA, USA.|University of Alaska Fairbanks, Fairbanks, AK, USA.
authors.forename: Claire
authors.initials: C
authors.lastname: Treat
authors.affiliation: Montana State University, Bozeman, MT, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Ewing
mesh_terms: D000413:Alaska; D002244:Carbon; D065928:Forests; D065946:Permafrost; D012987:Soil; D053833:Wetlands
chemical_list: D012987:Soil; D002244:Carbon
keywords: boreal; carbon; collapse-scar bog; peatland; permafrost; permafrost thaw