中国科学院南京土壤研究所梁玉婷的团队近日取得一项新成果。经过不懈努力，他们探明了全球变暖背景下湿地甲烷和二氧化碳排放量的相对增加依赖于土壤碳基质。这一研究成果发表在2024年1月3日出版的国际学术期刊《自然—地球科学》上。

研究人员通过结合全球数据库和大陆尺度的实验发现，全球湿地甲烷和二氧化碳排放(E_M/C)的温度依赖性差异取决于土壤碳氮化学计量。这主要可以通过土壤有机质分解率与E_M/C之间的正相关关系来解释。

研究表明，在未来变暖的情景下，考虑到土壤有机质的可分解性，相对于二氧化碳的排放，全球只有23%的湿地会减少甲烷排放。研究强调了将土壤有机质生物降解性纳入湿地碳—气候反馈模型预测的重要性。

据了解，令人信服的证据表明，在不同的水文条件下，湿地甲烷排放比二氧化碳排放更依赖于温度。然而，最终决定微生物碳代谢的碳基质可用性尚未得到充分考虑。

附：英文原文

Title: Relative increases in CH₄ and CO₂ emissions from wetlands under global warming dependent on soil carbon substrates

Author: Hu, Han, Chen, Ji, Zhou, Feng, Nie, Ming, Hou, Deyi, Liu, Huan, Delgado-Baquerizo, Manuel, Ni, Haowei, Huang, Weigen, Zhou, Jizhong, Song, Xianwei, Cao, Xiaofeng, Sun, Bo, Zhang, Jiabao, Crowther, Thomas W., Liang, Yuting

Issue&Volume: 2024-01-03

Abstract: Compelling evidence has shown that wetland methane emissions are more temperature dependent than carbon dioxide emissions across diverse hydrologic conditions. However, the availability of carbon substrates, which ultimately determines microbial carbon metabolism, has not been adequately accounted for. By combining a global database and a continental-scale experimental study, we showed that differences in the temperature dependence of global wetland methane and carbon dioxide emissions (EM/C) were dependent on soil carbon-to-nitrogen stoichiometry. This can be explained mainly by the positive relationship between soil organic matter decomposability and EM/C. Our study indicates that only 23% of global wetlands will decrease methane relative to carbon dioxide emissions under future warming scenarios when soil organic matter decomposability is considered. Our findings highlight the importance of incorporating soil organic matter biodegradability into model predictions of wetland carbon–climate feedback.

DOI: 10.1038/s41561-023-01345-6

Source: https://www.nature.com/articles/s41561-023-01345-6