Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands |
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| Authors: | Miriam C Jones Jennifer Harden Jonathan O'Donnell Kristen Manies Torre Jorgenson Claire Treat Stephanie Ewing |
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| Affiliation: | 1. U.S. Geological Survey, Reston, VA, USA;2. U.S. Geological Survey, Menlo Park, CA, USA;3. National Park Service, Anchorage, AK, USA;4. Ecoscience, Fairbanks, AK, USA;5. University of Alaska Fairbanks, Fairbanks, AK, USA;6. Montana State University, Bozeman, MT, USA |
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| 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. |
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| Keywords: | boreal carbon collapse‐scar bog peatland permafrost permafrost thaw |
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