永久冻土
缺氧水域
甲烷
温室气体
环境科学
碳纤维
二氧化碳
碳循环
全球变暖
总有机碳
环境化学
气候变化
化学
生态系统
生态学
海洋学
地质学
材料科学
有机化学
生物
复合数
复合材料
作者
Christian Knoblauch,Christian Beer,Susanne Liebner,Mikhail N. Grigoriev,Eva‐Maria Pfeiffer
标识
DOI:10.1038/s41558-018-0095-z
摘要
Permafrost thaw liberates frozen organic carbon, which is decomposed into carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) forms a positive feedback to atmospheric CO2 and CH4 concentrations and accelerates climate change1,2. Current studies report a minor importance of CH4 production in water-saturated (anoxic) permafrost soils3–6 and a stronger permafrost carbon–climate feedback from drained (oxic) soils1,7. Here we show through seven-year laboratory incubations that equal amounts of CO2 and CH4 are formed in thawing permafrost under anoxic conditions after stable CH4-producing microbial communities have established. Less permafrost carbon was mineralized under anoxic conditions but more CO2–carbon equivalents (CO2–Ce) were formed than under oxic conditions when the higher global warming potential (GWP) of CH4 is taken into account 8 . A model of organic carbon decomposition, calibrated with the observed decomposition data, predicts a higher loss of permafrost carbon under oxic conditions (113 ± 58 g CO2–C kgC−1 (kgC, kilograms of carbon)) by 2100, but a twice as high production of CO2–Ce (241 ± 138 g CO2–Ce kgC−1) under anoxic conditions. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils1,7 and emphasize the importance of CH4 production in thawing permafrost on climate-relevant timescales. An organic carbon decomposition model, calibrated with laboratory incubations, indicates a greater production rate of CO2-C equivalents from waterlogged (compared to drained) permafrost soils, when the higher global warming potential of methane is factored in.
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