Electron accepting capacity of dissolved and particulate organic matter control CO2 and CH4 formation in peat soils
Electron accepting capacity of dissolved and particulate organic matter control CO2 and CH4 formation in peat soils
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DOI：
10.1016/j.gca.2018.11.004
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发表时间：
2019-01-15
影响因子：
5
通讯作者：
Knorr, Klaus-Holger
中科院分区：
文献类型：
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作者：
Gao, Chuanyu;Sander, Michael;Knorr, Klaus-Holger
泥炭地是大气CH4的主要来源。末端电子受体的可用性在很大程度上影响了这些系统中淹水缺氧条件下CO2与CH（4）形成的比率。虽然泥炭有机物作为电子受体的重要性越来越被认识到，溶解和颗粒有机物的电子接受能力的实际预算仍然很差的特点。为了解决这一研究需求，我们培养了三种不同的泥炭材料，并将泥炭有机物（OM）（包括溶解和颗粒有机物）的电子接受能力（EAC）的变化与所观察到的CO2和CH4形成联系起来。在厌氧条件下，EAC（OM）的减少与非产甲烷CO2的形成相反。只有在可利用的EAC（OM）耗尽后，严格的产甲烷条件才以等摩尔的CH4和CO2形成速率发展，正如理论上预期的那样。OM的减少和由此产生的EAC（OM）的减少解释了26%至56%的非产甲烷CO2，占总CO2的5%至39%。与EAC（POM）相比，EAC（DOM）保持不变，可能是电子转移到POM的介体。综上所述，本研究定量地证明了泥炭有机质作为厌氧呼吸的末端电子受体在有机质土壤中的重要作用。(C)2018爱思唯尔有限公司版权所有。
Peatlands are a major source of atmospheric CH4. The availability of terminal electron acceptors largely affects the ratio of CO2 to CH(4 )formation under water-logged anoxic conditions in these systems. Although the importance of peat organic matter as an electron acceptor is increasingly recognized, the actual budgets of electron accepting capacities of dissolved and particulate organic matter remain poorly characterized. To address this research need, we incubated three different peat materials and linked changes in the electron accepting capacities (EAC) of peat organic matter (OM), including dissolved and particulate organic matter, to the observed CO2 and CH4 formation. Under anaerobic conditions, EAC(OM) decreased inverse to non-methanogenic CO2 formation. Only after utilizable EAC(OM) was depleted did strictly methanogenic conditions evolve with equimolar CH4 and CO2 formation rates, as theoretically expected. The reduction of OM and the resultant decrease in EAC(OM )explained between 26 and 56% of the non-methanogenic CO2, which was between 5 and 39% of total CO2 produced. Compared to EAC(POM), EAC(DOM )remained constant and may have served as a mediator in electron transfer to the POM. In summary, our study quantitatively demonstrated the important role of peat OM as terminal electron acceptor for anaerobic respiration in organic soils. (C) 2018 Elsevier Ltd. All rights reserved.