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Sediment Properties Drive Spatial Variability of Potential Methane Production and Oxidation in Small Streams
Author(s) -
Bodmer P.,
Wilkinson J.,
Lorke A.
Publication year - 2020
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2019jg005213
Subject(s) - sediment , methane , environmental science , streams , total organic carbon , spatial variability , greenhouse gas , dissolved organic carbon , organic matter , environmental chemistry , hydrology (agriculture) , deposition (geology) , carbon fibers , spatial ecology , chemistry , ecology , geology , oceanography , materials science , geomorphology , computer network , statistics , mathematics , geotechnical engineering , organic chemistry , computer science , biology , composite number , composite material
Emissions of the potent greenhouse gas methane (CH 4 ) from streams and rivers are a significant component of global freshwater methane emissions. The distribution of CH 4 production and oxidation within stream sections and in vertical sediment profiles is not well understood, and the environmental controls on CH 4 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 × 10 −4 to 28.58 μg CH 4 gDW −1 d −1 and PMO ranged from 0.43 μg CH 4 gDW −1 d −1 to 14.41 μg CH 4 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 CH 4 production and oxidation. These findings enhance our understanding of CH 4 dynamics, improve the potential for identifying CH 4 production hotspots in small streams, and provide a potential means for upscaling emission rates in larger‐scale assessments.