Trees are major conduits for methane egress from tropical forested wetlands
Trees are major conduits for methane egress from tropical forested wetlands
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DOI：
10.1111/nph.12031
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发表时间：
2013-01-01
期刊：
影响因子：
9.4
通讯作者：
Gauci, Vincent
中科院分区：
文献类型：
--
作者：
Pangala, Sunitha R.;Moore, Sam;Gauci, Vincent
湿地是大气中甲烷的最大来源，热带湿地是全球最重要的湿地来源。一些适应湿地的树种的树干可以促进甲烷从缺氧土壤中排出，但是目前用于确定森林湿地甲烷存量的地面通量室方法忽略了这一排放途径，因此，树木介导的排放对生态系统总甲烷通量的贡献仍然未知。泥炭地表面（积水坑和丘）和根通气pneumatophores在热带森林泥炭地在东南亚。我们表明，树干排放的甲烷比泥炭表面，占62-87%的总生态系统甲烷通量。树干通量强度受树干直径、木材比密度和孔隙水中溶解的甲烷量的控制，我们的研究结果强调，如果湿地甲烷通量要准确地表征全球甲烷预算，基于实地的通量清单与对热带地区甲烷排放量自上而下的估计之间存在的差异有待调和。
Wetlands are the largest source of methane to the atmosphere, with tropical wetlands comprising the most significant global wetland source component. The stems of some wetland-adapted tree species are known to facilitate egress of methane from anoxic soil, but current ground-based flux chamber methods for determining methane inventories in forested wetlands neglect this emission pathway, and consequently, the contribution of tree-mediated emissions to total ecosystem methane flux remains unknown.In this study, we quantify in situ methane emissions from tree stems, peatland surfaces (ponded hollows and hummocks) and root-aerating pneumatophores in a tropical forested peatland in Southeast Asia.We show that tree stems emit substantially more methane than peat surfaces, accounting for 62-87% of total ecosystem methane flux. Tree stem flux strength was controlled by the stem diameter, wood specific density and the amount of methane dissolved in pore water.Our findings highlight the need to integrate this emission pathway in both field studies and models if wetland methane fluxes are to be characterized accurately in global methane budgets, and the discrepancies that exist between field-based flux inventories and top-down estimates of methane emissions from tropical areas are to be reconciled.