Investigating Thaw and Plant Productivity Constraints on Old Soil Carbon Respiration From Permafrost
Investigating Thaw and Plant Productivity Constraints on Old Soil Carbon Respiration From Permafrost
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研究解冻和植物生产力对多年冻土旧土壤碳呼吸的限制
DOI：
10.1029/2020jg006000
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Schuur, Edward A. G.
中科院分区：
文献类型：
--
作者：
Mauritz, Marguerite;Pegoraro, Elaine;Ogle, Kiona;Ebert, Christopher;Schuur, Edward A. G.
生态系统呼吸 (Reco) 的同位素放射性碳 (Δ14C) 特征可以识别旧土壤碳 (C) 损失，并作为气候变暖中永久冻土不稳定的早期指标。变暖还刺激植物生产力，导致植物呼吸主导 Reco Δ14C 特征，并可能掩盖旧土壤碳损失。在这里，我们研究了永久冻土融化和植物生产力的宽时空梯度如何影响 Reco Δ14C 模式和同位素分配。空间梯度来自加倍解冻深度和可变生物量的变暖实验，以及消除植物贡献的植被去除操作。我们在八月和九月进行了采样，以捕捉植物生产力从高到低的转变、表层土壤温度下降以及相对较小的季节性解冻延伸。我们发现，地表过程主导了旧土壤碳流失的空间变化，基于过程的分区方法对于限制旧土壤碳流失至关重要。在一年中不同时间对相同地块进行重新采样表明，随着地表温度的降低，旧土壤碳损失增加了两倍，并且当有机-矿物质土壤层解冻（〜50-60厘米）时检测到最大的旧土壤碳损失。我们认为，在整个季节和有机矿物层解冻时测量到的旧土壤呼吸的增加可能是由于氮的动员刺激了深层微生物的分解来解释的。我们的结果表明，随着整个北极地区变暖，有机到矿物层中的土壤碳可能是土壤碳损失的重要来源，并可能导致预计的永久冻土气候反馈的非线性。
Isotopic radiocarbon (Δ14C) signatures of ecosystem respiration (Reco) can identify old soil carbon (C) loss and serve as an early indicator of permafrost destabilization in a warming climate. Warming also stimulates plant productivity causing plant respiration to dominate Reco Δ14C signatures and potentially obscuring old soil C loss. Here, we investigate how a wide spatio‐temporal gradient of permafrost thaw and plant productivity affects Reco Δ14C patterns and isotopic partitioning. Spatial gradients came from a warming experiment with doubling thaw depth and variable biomass, and a vegetation removal manipulation to eliminate plant contributions. We sampled in August and September to capture transitions from high to low plant productivity, decreased surface soil temperature, and relatively small seasonal thaw extensions. We found that surface processes dominate spatial variation in old soil C loss and a process‐based partitioning approach was crucial for constraining old soil C loss. Resampling the same plots in different times of the year revealed that old soil C losses tripled with cooling surface temperature, and the largest old soil C losses were detected when the organic‐to‐mineral soil horizons thawed (∼50–60 cm). We suggest that the measured increase in old soil respiration over the season and when the organic‐to‐mineral horizon thawed, may be explained by mobilization of nitrogen that stimulates microbial decomposition at depth. Our results suggest that soil C in the organic to mineral horizon may be an important source of soil C loss as the entire Arctic region warms and could lead to nonlinearities in projected permafrost climate feedbacks.
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DOI：
10.1073/pnas.1811797116
发表时间：
2019-05
影响因子：
11.1
作者：
B. Wild;A. Andersson;L. Bröder;J. Vonk;G. Hugelius;J. McClelland;Wenjun Song;P. Raymond;Ö. Gustaf
通讯作者：
B. Wild;A. Andersson;L. Bröder;J. Vonk;G. Hugelius;J. McClelland;Wenjun Song;P. Raymond;Ö. Gustaf
影响因子：
9.7
作者：
Olsrud, Maria;Christensen, Torben R.
通讯作者：
Christensen, Torben R.
影响因子：
30.7
作者：
C. Schädel;M. Bader;E. Schuur;C. Biasi;R. Bracho;P. Čapek;S. Baets;K. Diáková;J. Ernakovich
通讯作者：
C. Schädel;M. Bader;E. Schuur;C. Biasi;R. Bracho;P. Čapek;S. Baets;K. Diáková;J. Ernakovich
DOI：
10.1073/pnas.1719903115
发表时间：
2018-04-10
影响因子：
11.1
作者：
McGuire AD;Lawrence DM;Koven C;Clein JS;Burke E;Chen G;Jafarov E;MacDougall AH;Marchenko S;Nicolsky D;Peng S;Rinke A;Ciais P;Gouttevin I;Hayes DJ;Ji D;Krinner G;Moore JC;Romanovsky V;Schädel C;Schaefer K;Schuur EAG;Zhuang Q
通讯作者：
Zhuang Q
放射性碳与气候
影响因子：
9.7
作者：
P. Damon
通讯作者：
P. Damon