瑞典于默奥大学 Rocher-Ros, Gerard 的团队在研究全球河流和溪流的甲烷排放中取得新进展。2023年8月16日，国际知名学术期刊《自然》发表了这一成果。

研究团队报告了一个来自流动水域的 CH₄ 排放的空间显式的全球估计值，占每年(16.7–39.7)Tg CH₄ 的27.9，在数量级上与其他淡水系统大致相等。与湖泊和湿地的平均活化能(E_M = 0.96 eV)相比，河流 CH₄ 排放并不强烈依赖于温度，其平均活化能(E_M = 0.14 eV)较低。相比之下，全球排放模式的特点是在高纬度和低纬度环境以及人类主导的环境中通量较大。这些模式可以用土壤和气候特征来解释，这些特征与河流生境及其附近的缺氧有关，包括水文相关土壤中有机质的大量供应和水饱和。

研究结果强调了陆水连接在调节 CH₄ 向流水供应中的重要性，流水不仅易受人类直接改变的影响，也易受陆地上几种气候变化反应的影响。

研究人员表示，甲烷(CH₄)是一种强有力的温室气体，自工业革命以来，其在大气中的浓度增加了两倍。有证据表明，全球变暖增加了淡水生态系统的 CH₄ 排放，为全球气候提供了积极的反馈。然而，对于河流和溪流来说，甲烷排放的控制和数量仍然非常不确定。

附：英文原文

Title: Global methane emissions from rivers and streams

Author: Rocher-Ros, Gerard, Stanley, Emily H., Loken, Luke C., Casson, Nora J., Raymond, Peter A., Liu, Shaoda, Amatulli, Giuseppe, Sponseller, Ryan A.

Issue&Volume: 2023-08-16

Abstract: Methane ( CH₄) is a potent greenhouse gas and its concentrations have tripled in the atmosphere since the industrial revolution. There is evidence that global warming has increased CH₄ emissions from freshwater ecosystems, providing positive feedback to the global climate. Yet for rivers and streams, the controls and the magnitude of CH₄emissions remain highly uncertain. Here we report a spatially explicit global estimate of CH₄emissions from running waters, accounting for 27.9 (16.7–39.7) Tg CH₄per year and roughly equal in magnitude to those of other freshwater systems. Riverine CH₄emissions are not strongly temperature dependent, with low average activation energy (E_M=0.14eV) compared with that of lakes and wetlands (E_M=0.96eV). By contrast, global patterns of emissions are characterized by large fluxes in high- and low-latitude settings as well as in human-dominated environments. These patterns are explained by edaphic and climate features that are linked to anoxia in and near fluvial habitats, including a high supply of organic matter and water saturation in hydrologically connected soils. Our results highlight the importance of land–water connections in regulating CH₄supply to running waters, which is vulnerable not only to direct human modifications but also to several climate change responses on land.

DOI: 10.1038/s41586-023-06344-6

Source: https://www.nature.com/articles/s41586-023-06344-6