Carbon Accumulation, Flux, and Fate in Stordalen Mire, a Permafrost Peatland in Transition
Carbon Accumulation, Flux, and Fate in Stordalen Mire, a Permafrost Peatland in Transition
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DOI：
10.1029/2021gb007113
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发表时间：
2022-01
影响因子：
5.2
通讯作者：
M. Holmes;P. M. Crill;W. Burnett;C. McCalley;R. Wilson;S. Frolking;Kuan-Yu Chang;W. Riley;R. Varner;S. Hodgkins;A. McNichol;S. Saleska;V. Rich;J. Chanton
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作者：
M. Holmes;P. M. Crill;W. Burnett;C. McCalley;R. Wilson;S. Frolking;Kuan-Yu Chang;W. Riley;R. Varner;S. Hodgkins;A. McNichol;S. Saleska;V. Rich;J. Chanton
Stordalen Mire是瑞典北极地区不连续永久冻土区的泥炭地，从永久冻土层到永久冻土层下的泥炭藓沼泽，再到以Eriophorum为主的完全解冻的沼泽，其栖息地梯度很大。我们使用了三种独立的方法来评估这一梯度上的年度、数十年和千年表观碳积累率（aCAR）：7年的CO2和CH 4交换直接半连续测量，以及210 Pb和14 C泥炭测年的21个岩心剖面。全年室内测量表明，2012-2018年，帕尔萨、沼泽和沼泽的净碳平衡分别为−13 ± 8、−49 ± 15和−91 ± 43 g C m−2 y−1。甲烷排放抵消了2%，7%和17%的二氧化碳吸收率在这个梯度。最近的aCAR表明，较高的C积累率在表面泥炭在棕榈和沼泽相比，目前的CO2通量，但这些评估是更相似的沼泽。aCAR从千年尺度的低水平（17-29 g C m−2 y−1）增加到过去世纪的中等aCAR（72-81 g C m−2 y−1），再到最近的较高aCAR（90-147 g C m−2 y −1）。最近的永久冻土崩塌，更大的洪水和植被响应使景观成为更强的CO2汇，但这种CO2汇越来越多地被CH 4排放量的增加所抵消，其中以14 C确定的现代碳为主。较高的甲烷排放量导致较高的净二氧化碳当量排放量，表明该沼泽和类似的永久冻土生态系统的辐射强迫将对未来气候产生变暖影响。
Stordalen Mire is a peatland in the discontinuous permafrost zone in arctic Sweden that exhibits a habitat gradient from permafrost palsa, to Sphagnum bog underlain by permafrost, to Eriophorum‐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 CO2 and CH4 exchange, and 21 core profiles for 210Pb and 14C peat dating. Year‐round chamber measurements indicated net carbon balance of −13 ± 8, −49 ± 15, and −91 ± 43 g C m−2 y−1 for the years 2012–2018 in palsa, bog, and fen, respectively. Methane emission offset 2%, 7%, and 17% of the CO2 uptake rate across this gradient. Recent aCAR indicates higher C accumulation rates in surface peats in the palsa and bog compared to current CO2 fluxes, 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 CO2 sink, but this CO2 sink is increasingly offset by rising CH4 emissions, dominated by modern carbon as determined by 14C. The higher CH4 emissions result in higher net CO2‐equivalent emissions, indicating that radiative forcing of this mire and similar permafrost ecosystems will exert a warming influence on future climate.