A synthesis of methane emissions from 71 northern, temperate, and subtropical wetlands
A synthesis of methane emissions from 71 northern, temperate, and subtropical wetlands
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DOI：
10.1111/gcb.12580
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发表时间：
2014-07
影响因子：
11.6
通讯作者：
M. Turetsky;A. Kotowska;J. Bubier;N. Dise;P. Crill;E. Hornibrook;K. Minkkinen;T. Moore;I. Myers-Smith
中科院分区：
文献类型：
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作者：
M. Turetsky;A. Kotowska;J. Bubier;N. Dise;P. Crill;E. Hornibrook;K. Minkkinen;T. Moore;I. Myers-Smith
湿地是大气甲烷的最大天然来源。在这里，我们评估控制甲烷通量使用的数据库约19000瞬时测量71个湿地位于亚热带，温带和北方高纬度地区。我们的分析证实了一般控制湿地甲烷排放的土壤温度，地下水位，植被，但也表明，这些关系的修改取决于湿地类型（沼泽，沼泽，沼泽），区域（亚北极温带），和干扰。沼泽甲烷通量对植被的敏感性高于沼泽和沼泽，对温度的敏感性低于沼泽和沼泽。甲烷通量的最佳水位始终低于泥炭表面的沼泽，接近泥炭表面的穷人沼泽，并在泥炭表面上丰富的沼泽。然而，最大的通量在沼泽发生时，干燥的30天平均前期条件其次是潮湿的条件，而在沼泽和沼泽，最大的通量发生时，30天平均前期和当前条件都是潮湿的。排水湿地表现出独特的特点，例如，没有大通量以下的潮湿和温暖的条件下，这表明甲烷通量和环境条件之间的相同的功能关系不能用于整个原始和扰动湿地。总之，我们的研究结果表明，地下水位和温度是占主导地位的控制甲烷通量在原始沼泽和沼泽，而其他过程，如血管运输在原始沼泽，有可能部分推翻这些控制在其他湿地类型的影响。由于湿地类型的甲烷排放量各不相同，并有不同的控制，这些生态系统需要单独考虑，以产生可靠的估计全球湿地甲烷释放。
Wetlands are the largest natural source of atmospheric methane. Here, we assess controls on methane flux using a database of approximately 19 000 instantaneous measurements from 71 wetland sites located across subtropical, temperate, and northern high latitude regions. Our analyses confirm general controls on wetland methane emissions from soil temperature, water table, and vegetation, but also show that these relationships are modified depending on wetland type (bog, fen, or swamp), region (subarctic to temperate), and disturbance. Fen methane flux was more sensitive to vegetation and less sensitive to temperature than bog or swamp fluxes. The optimal water table for methane flux was consistently below the peat surface in bogs, close to the peat surface in poor fens, and above the peat surface in rich fens. However, the largest flux in bogs occurred when dry 30‐day averaged antecedent conditions were followed by wet conditions, while in fens and swamps, the largest flux occurred when both 30‐day averaged antecedent and current conditions were wet. Drained wetlands exhibited distinct characteristics, e.g. the absence of large flux following wet and warm conditions, suggesting that the same functional relationships between methane flux and environmental conditions cannot be used across pristine and disturbed wetlands. Together, our results suggest that water table and temperature are dominant controls on methane flux in pristine bogs and swamps, while other processes, such as vascular transport in pristine fens, have the potential to partially override the effect of these controls in other wetland types. Because wetland types vary in methane emissions and have distinct controls, these ecosystems need to be considered separately to yield reliable estimates of global wetland methane release.