Sediment Properties Drive Spatial Variability of Potential Methane Production and Oxidation in Small Streams
Sediment Properties Drive Spatial Variability of Potential Methane Production and Oxidation in Small Streams
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DOI：
10.1029/2019jg005213
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发表时间：
2020-01-01
影响因子：
3.7
通讯作者：
Lorke, A.
中科院分区：
文献类型：
--
作者：
Bodmer, P.;Wilkinson, J.;Lorke, A.
来自溪流和河流的强效温室气体甲烷（CH 4）排放是全球淡水甲烷排放的重要组成部分。对CH 4产生和氧化在河流断面和沉积物垂直剖面中的分布还没有很好的了解，在这种系统中对CH 4产生和排放的环境控制对评估更大规模的动态构成了重大挑战。在这里，我们调查的驱动因素的空间变异性的沉积物潜在的甲烷生产（PMP）和潜在的甲烷氧化（PMO）在温带河流网络在德国。PMP变化很大，范围为5 x 10（-4）至28.58 μ g CH 4 gDW（-1）d（-1），PMO范围为0.43 μ g CH 4 gDW（-1）d（-1）至14.41 μ g CH 4 gDW（-1）d（-1）。河流主茎沉积物中PMP和PMO空间变异的重要驱动因素与细颗粒物组分和有机碳含量有关。在较小的空间尺度上，也就是说，在一个子集水区流段，驱动程序更为复杂，包括沉积物氮和有机碳含量，以及孔隙水溶解有机碳，溶解有机质的质量，和金属浓度。与水库和蓄水河流一样，细泥沙沉积和有机碳含量被认为是控制CH 4生产和氧化空间变异的关键因素。这些发现增强了我们对CH 4动力学的理解，提高了在小溪流中确定CH 4生产热点的潜力，并为在大规模评估中提高排放率提供了一种潜在的手段。
Emissions of the potent greenhouse gas methane (CH4) from streams and rivers are a significant component of global freshwater methane emissions. The distribution of CH4 production and oxidation within stream sections and in vertical sediment profiles is not well understood, and the environmental controls on CH4 production and emission in such systems create a significant challenge for assessing larger-scale dynamics. Here we investigate factors driving the spatial variability of sediment potential methane production (PMP) and potential methane oxidation (PMO) in a temperate stream network in Germany. PMP was highly variable, ranging from 5 x 10(-4) to 28.58 mu g CH4 gDW(-1) d(-1) and PMO ranged from 0.43 mu g CH4 gDW(-1) d(-1) to 14.41 mu g CH4 gDW(-1) d(-1). Important drivers of spatial variability of PMP and PMO in the sediments of the stream main-stem were related to fine sediment fraction and organic carbon content. At smaller spatial scale, that is, in a sub-catchment stream section, the drivers were more complex and included sediment nitrogen and organic carbon content, as well as porewater dissolved organic carbon, dissolved organic matter quality, and metal concentrations. As with reservoirs and impounded rivers, fine sediment deposition and organic carbon content were found to be key controls on the spatial variability of CH4 production and oxidation. These findings enhance our understanding of CH4 dynamics, improve the potential for identifying CH4 production hotspots in small streams, and provide a potential means for upscaling emission rates in larger-scale assessments.