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. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.
资助项目:
Jones, M.C.
; U.S. Geological SurveyUnited States
; 电子邮件: miriamjones@usgs.gov
U.S. Geological Survey, Reston, VA, United States; U.S. Geological Survey, Menlo Park, CA, United States; National Park Service, Anchorage, AK, United States; Ecoscience, Fairbanks, AK, United States; University of Alaska Fairbanks, Fairbanks, AK, United States; Montana State University, Bozeman, MT, United States
Recommended Citation:
Jones M.C.,Harden J.,O'Donnell J.,et al. Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands[J]. Global Change Biology,2017-01-01,23(3)