McEwing Katherine Rose, Fisher James Paul, Zona Donatella
Department of Animal and Plant Science, University of Sheffield, Western Bank, Sheffield S10 2TN UK.
Department of Animal and Plant Science, University of Sheffield, Western Bank, Sheffield S10 2TN UK ; Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 USA.
Plant Soil. 2015;388(1-2):37-52. doi: 10.1007/s11104-014-2377-1. Epub 2015 Jan 11.
Despite multiple studies investigating the environmental controls on CH fluxes from arctic tundra ecosystems, the high spatial variability of CH emissions is not fully understood. This makes the upscaling of CH fluxes from plot to regional scale, particularly challenging. The goal of this study is to refine our knowledge of the spatial variability and controls on CH emission from tundra ecosystems.
CH fluxes were measured in four sites across a variety of wet-sedge and tussock tundra ecosystems in Alaska using chambers and a Los Gatos CO and CH gas analyser.
All sites were found to be sources of CH, with northern sites (in Barrow) showing similar CH emission rates to the southernmost site (ca. 300 km south, Ivotuk). Gross primary productivity (GPP), water level and soil temperature were the most important environmental controls on CH emission. Greater vascular plant cover was linked with higher CH emission, but this increased emission with increased vascular plant cover was much higher (86 %) in the drier sites, than the wettest sites (30 %), suggesting that transport and/or substrate availability were crucial limiting factors for CH emission in these tundra ecosystems.
Overall, this study provides an increased understanding of the fine scale spatial controls on CH flux, in particular the key role that plant cover and GPP play in enhancing CH emissions from tundra soils.
尽管有多项研究调查了北极苔原生态系统中甲烷通量的环境控制因素，但甲烷排放的高空间变异性仍未得到充分理解。这使得将甲烷通量从样地尺度扩展到区域尺度极具挑战性。本研究的目的是完善我们对苔原生态系统中甲烷排放的空间变异性及其控制因素的认识。
在阿拉斯加各种湿苔草和丘状苔原生态系统的四个地点，使用气室和洛斯加托斯一氧化碳和甲烷气体分析仪测量甲烷通量。
所有地点均为甲烷源，北部地点（巴罗）的甲烷排放率与最南端地点（向南约300公里处的伊沃图克）相似。总初级生产力（GPP）、水位和土壤温度是甲烷排放最重要的环境控制因素。维管束植物覆盖率越高，甲烷排放越高，但在较干燥的地点，随着维管束植物覆盖率增加而增加的排放量（86%）远高于最湿润的地点（30%），这表明传输和/或底物可用性是这些苔原生态系统中甲烷排放的关键限制因素。
总体而言，本研究增进了我们对甲烷通量精细尺度空间控制的理解，特别是植物覆盖和总初级生产力在增强苔原土壤甲烷排放中所起的关键作用。
