Soil incubations reproduce field methane dynamics in a subarctic wetland
Soil incubations reproduce field methane dynamics in a subarctic wetland
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DOI：
10.1007/s10533-015-0142-z
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发表时间：
2015-11-01
期刊：
影响因子：
4
通讯作者：
Cooper, William T.
中科院分区：
文献类型：
--
作者：
Hodgkins, Suzanne B.;Chanton, Jeffrey P.;Cooper, William T.
泥炭地碳循环建模的一个主要挑战是估计地下甲烷（CH 4）和二氧化碳（CO2）的生产和消费速率和途径。模拟这些过程的最常见的方法是土壤培养和稳定同位素模拟，这两种方法都可能涉及偏离现场条件。为了探索这些偏离的影响，我们测量了CH 4/CO2的浓度比和C-13分馏因子（α（C），表明CH 4生产途径）从解冻的亚北极泥炭地领域孔隙水，并比较这些值的孵化相应的泥炭样品中观察到的。孵育CH 4/CO2生产率显着和正相关，与观察到的字段CH 4/CO2浓度比，虽然观察到的字段比相似的20%，在孵育由于CH 4在孔隙水中的溶解度较低。在用同位素质量平衡模型校正CH 4损失的场比后，孵育CH 4/CO2比和α（C）均与场比和α（C）（分别）显著正相关，两者的斜率与1不可区分。虽然CH 4/CO2比和α（C）在孵育中略高，但这些变化沿着解冻进程是一致的，表明非原位孵育可以复制原位CH 4产生的趋势。
A major challenge in peatland carbon cycle modeling is the estimation of subsurface methane (CH4) and carbon dioxide (CO2) production and consumption rates and pathways. The most common methods for modeling these processes are soil incubations and stable isotope modeling, both of which may involve departures from field conditions. To explore the impacts of these departures, we measured CH4/CO2 concentration ratios and C-13 fractionation factors (alpha(C), indicating CH4 production pathways) in field pore water from a thawing subarctic peatland, and compared these values to those observed in incubations of corresponding peat samples. Incubation CH4/CO2 production ratios were significantly and positively correlated with observed field CH4/CO2 concentration ratios, though observed field ratios were similar to 20 % of those in incubations due to CH4's lower solubility in pore water. After correcting the field ratios for CH4 loss with an isotope mass balance model, the incubation CH4/CO2 ratios and alpha(C) were both significantly positively correlated with field ratios and alpha(C) (respectively), both with slopes indistinguishable from 1. Although CH4/CO2 ratios and alpha(C) were slightly higher in the incubations, these shifts were consistent along the thaw progression, indicating that ex situ incubations can replicate trends in in situ CH4 production.