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Coupled anaerobic methane oxidation and metal reduction in soil under elevated CO2
Global Change Biology ( IF 10.8 ) Pub Date : 2023-05-23 , DOI: 10.1111/gcb.16763
Chenchao Xu 1 , Naifang Zhang 1 , Kaihang Zhang 1 , Shuyao Li 1 , Qing Xia 1 , Jing Xiao 1 , Maojun Liang 1 , Weilei Lei 1 , Junpan He 1 , Gaiping Chen 1 , Chengjun Ge 2 , Xunhua Zheng 3 , Jianguo Zhu 4 , Shuijin Hu 5 , Roger T Koide 6 , Mary K Firestone 7 , Lei Cheng 1
Affiliation  

Continued current emissions of carbon dioxide (CO2) and methane (CH4) by human activities will increase global atmospheric CO2 and CH4 concentrations and surface temperature significantly. Fields of paddy rice, the most important form of anthropogenic wetlands, account for about 9% of anthropogenic sources of CH4. Elevated atmospheric CO2 may enhance CH4 production in rice paddies, potentially reinforcing the increase in atmospheric CH4. However, what is not known is whether and how elevated CO2 influences CH4 consumption under anoxic soil conditions in rice paddies, as the net emission of CH4 is a balance of methanogenesis and methanotrophy. In this study, we used a long-term free-air CO2 enrichment experiment to examine the impact of elevated CO2 on the transformation of CH4 in a paddy rice agroecosystem. We demonstrate that elevated CO2 substantially increased anaerobic oxidation of methane (AOM) coupled to manganese and/or iron oxides reduction in the calcareous paddy soil. We further show that elevated CO2 may stimulate the growth and metabolism of Candidatus Methanoperedens nitroreducens, which is actively involved in catalyzing AOM when coupled to metal reduction, mainly through enhancing the availability of soil CH4. These findings suggest that a thorough evaluation of climate-carbon cycle feedbacks may need to consider the coupling of methane and metal cycles in natural and agricultural wetlands under future climate change scenarios.

中文翻译:

高二氧化碳条件下土壤中厌氧甲烷氧化和金属还原的耦合

当前人类活动持续排放二氧化碳(CO 2 )和甲烷(CH 4 )将显着增加全球大气CO 2和CH 4浓度以及地表温度。稻田是人为湿地最重要的形式,约占CH 4人为来源的9% 。大气中CO 2升高可能会增加稻田中CH 4 的产量,从而可能加剧大气中CH 4的增加。然而,尚不清楚 CO 2升高是否以及如何影响 CH 4稻田缺氧土壤条件下的消耗,因为CH 4的净排放是产甲烷作用和甲烷氧化作用的平衡。在本研究中,我们采用长期自由空气CO 2富集实验来研究CO 2升高对水稻农业生态系统中CH 4转化的影响。我们证明,升高的CO 2显着增加了甲烷的厌氧氧化(AOM),同时钙质稻田土壤中锰和/或铁的氧化物减少了。我们进一步表明,升高的 CO 2可能会刺激Candidatus Methanoperedens nitroreducens的生长和代谢,当与金属还原结合时,它积极参与催化 AOM,主要是通过提高土壤 CH 4的可用性。这些发现表明,对气候-碳循环反馈的全面评估可能需要考虑未来气候变化情景下自然和农业湿地中甲烷和金属循环的耦合。
更新日期:2023-05-23
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