Strock Kristin E, Krewson Rachel B, Hayes Nicole M, Deemer Bridget R
Environmental Science Department, Dickinson College, Carlisle, PA, 17013, USA.
Biology Department, University of Wisconsin Stout, Menomonie, WI, 54751, USA.
Sci Rep. 2024 Oct 8;14(1):23389. doi: 10.1038/s41598-024-73041-3.
Globally, aquatic ecosystems are one of the largest but most uncertain sources of methane, a potent greenhouse gas. It is unclear how climate change will affect methane emissions, but recent work suggests that glacial systems, which are melting faster with climate change, may be an important source of methane to the atmosphere. Currently, studies quantifying glacial emissions are limited in number, and the role of methanotrophy, or microbial methane oxidizers, in reducing atmospheric emissions from source and receiving waters is not well known. Here we discuss three potential sites for methane oxidation that could mitigate emissions from glaciers into the atmosphere: under ice oxidation, oxidation within proglacial lakes, and oxidation within melt rivers. The research presented here increases the number of glacial sites with methane concentration data and is one of only a few studies to quantify the net microbial activity of methane production and oxidation in two types of land-terminating glacial runoff (lake and river). We find that oxidation in a glacial river may reduce atmospheric methane emissions from glacial melt by as much as 53%. Incorporating methane oxidation in estimates of glacial methane emissions may significantly reduce the estimated magnitude of this source in budgeting exercises.
在全球范围内，水生生态系统是甲烷这一强效温室气体最大但最不确定的来源之一。目前尚不清楚气候变化将如何影响甲烷排放，但近期研究表明，随着气候变化而加速融化的冰川系统可能是大气中甲烷的一个重要来源。目前，量化冰川排放的研究数量有限，且甲烷氧化作用（即微生物甲烷氧化菌）在减少源头水和受纳水体向大气排放甲烷方面所起的作用尚不明确。在此，我们讨论了三个可能减轻冰川向大气排放甲烷的甲烷氧化潜在场所：冰下氧化、冰前湖内氧化以及融水河内氧化。本文所呈现的研究增加了有甲烷浓度数据的冰川场所数量，并且是为数不多的量化两种陆地终端冰川径流（湖泊和河流）中甲烷产生和氧化的净微生物活性的研究之一。我们发现，冰川河流中的氧化作用可能使冰川融水向大气排放的甲烷减少多达53%。在估算冰川甲烷排放时纳入甲烷氧化作用，可能会在预算编制过程中显著降低该来源的估算量。
