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Title: Carbon Accumulation, Flux, and Fate in Stordalen Mire, a Permafrost Peatland in Transition
Abstract

Stordalen Mire is a peatland in the discontinuous permafrost zone in arctic Sweden that exhibits a habitat gradient from permafrost palsa, toSphagnumbog underlain by permafrost, toEriophorum‐dominated fully thawed fen. We used three independent approaches to evaluate the annual, multi‐decadal, and millennial apparent carbon accumulation rates (aCAR) across this gradient: seven years of direct semi‐continuous measurement of CO2and CH4exchange, and 21 core profiles for210Pb and14C peat dating. Year‐round chamber measurements indicated net carbon balance of −13 ± 8, −49 ± 15, and −91 ± 43 g C m−2 y−1for the years 2012–2018 in palsa, bog, and fen, respectively. Methane emission offset 2%, 7%, and 17% of the CO2uptake rate across this gradient. Recent aCAR indicates higher C accumulation rates in surface peats in the palsa and bog compared to current CO2fluxes, but these assessments are more similar in the fen. aCAR increased from low millennial‐scale levels (17–29 g C m−2 y−1) to moderate aCAR of the past century (72–81 g C m−2 y−1) to higher recent aCAR of 90–147 g C m−2 y−1. Recent permafrost collapse, greater inundation and vegetation response has made the landscape a stronger CO2sink, but this CO2sink is increasingly offset by rising CH4emissions, dominated by modern carbon as determined by14C. The higher CH4emissions result in higher net CO2‐equivalentemissions, indicating that radiative forcing of this mire and similar permafrost ecosystems will exert a warming influence on future climate.

 
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Award ID(s):
1755125 2022070
NSF-PAR ID:
10362281
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  ;  ; ; ;  ;  ;  ;  
Publisher / Repository:
DOI PREFIX: 10.1029
Date Published:
Journal Name:
Global Biogeochemical Cycles
Volume:
36
Issue:
1
ISSN:
0886-6236
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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