Improved global wetland carbon isotopic signatures support post-2006 microbial methane emission increase
Improved global wetland carbon isotopic signatures support post-2006 microbial methane emission increase
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DOI：
10.1038/s43247-022-00488-5
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发表时间：
2022-07
影响因子：
7.9
通讯作者：
Y. Oh;Q. Zhuang;L. Welp;Licheng Liu;X. Lan;S. Basu;E. Dlugokencky;L. Bruhwiler;John B. Miller;S. Michel;S. Schwietzke;P. Tans;P. Ciais;J. Chanton
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文献类型：
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作者：
Y. Oh;Q. Zhuang;L. Welp;Licheng Liu;X. Lan;S. Basu;E. Dlugokencky;L. Bruhwiler;John B. Miller;S. Michel;S. Schwietzke;P. Tans;P. Ciais;J. Chanton
自2007年以来，甲烷这种强大的温室气体的大气浓度大幅增加。甲烷的稳定碳同位素的测量可以限制排放，如果同位素组成是已知的，但是，从湿地甲烷排放的同位素组成的限制很差，尽管它们的重要性。在这里，我们使用一个基于过程的地球化学模型来计算全球湿地甲烷排放的稳定碳同位素组成。我们估计全球平均特征为−61.3 ± 0.7‰，发现热带湿地的排放量相对于北方湿地增加了约11‰。我们的模型显示了提高分辨率的区域，纬度和全球变化的同位素组成的湿地排放。改进湿地同位素组成的大气模拟情景表明，自2007年以来大气甲烷的增加可归因于微生物排放的增加。我们的研究结果大大减少了湿地甲烷排放的稳定碳同位素组成的不确定性，并提高了对全球甲烷预算的理解。
Atmospheric concentrations of methane, a powerful greenhouse gas, have strongly increased since 2007. Measurements of stable carbon isotopes of methane can constrain emissions if the isotopic compositions are known; however, isotopic compositions of methane emissions from wetlands are poorly constrained despite their importance. Here, we use a process-based biogeochemistry model to calculate the stable carbon isotopic composition of global wetland methane emissions. We estimate a mean global signature of −61.3 ± 0.7‰ and find that tropical wetland emissions are enriched by ~11‰ relative to boreal wetlands. Our model shows improved resolution of regional, latitudinal and global variations in isotopic composition of wetland emissions. Atmospheric simulation scenarios with the improved wetland isotopic composition suggest that increases in atmospheric methane since 2007 are attributable to rising microbial emissions. Our findings substantially reduce uncertainty in the stable carbon isotopic composition of methane emissions from wetlands and improve understanding of the global methane budget.