Aquatic Physics Group, Department F.-A. Forel for Environmental and Aquatic Sciences (DEFSE), Faculty of Science, University of Geneva, Uni Carl Vogt, 66 Boulevard Carl-Vogt, 1211, Geneva, Switzerland.
Now at Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, Canada.
Nat Commun. 2023 Apr 15;14(1):2165. doi: 10.1038/s41467-023-37861-7.
Contrasting the paradigm that methane is only produced in anoxic conditions, recent discoveries show that oxic methane production (OMP, aka the methane paradox) occurs in oxygenated surface waters worldwide. OMP drivers and their contribution to global methane emissions, however, are not well constrained. In four adjacent pre-alpine lakes, we determine the net methane production rates in oxic surface waters using two mass balance approaches, accounting for methane sources and sinks. We find that OMP occurs in three out of four studied lakes, often as the dominant source of diffusive methane emissions. Correlations of net methane production versus chlorophyll-a, Secchi and surface mixed layer depths suggest a link with photosynthesis and provides an empirical upscaling approach. As OMP is a methane source in direct contact with the atmosphere, a better understanding of its extent and drivers is necessary to constrain the atmospheric methane contribution by inland waters.
与甲烷仅在缺氧条件下产生的范式相反，最近的发现表明，在全球富氧地表水层中存在好氧产甲烷作用（OMP，又名甲烷悖论）。然而，OMP 的驱动因素及其对全球甲烷排放的贡献尚不清楚。在四个相邻的山前湖泊中，我们使用两种质量平衡方法来确定好氧地表水层中的净甲烷产生速率，同时考虑甲烷的源和汇。我们发现，OMP 存在于四个研究湖泊中的三个湖泊中，通常是扩散甲烷排放的主要来源。净甲烷产生与叶绿素 a、塞奇深度和表层混合层深度的相关性表明其与光合作用有关，并提供了一种经验性的扩展方法。由于 OMP 是与大气直接接触的甲烷源，因此需要更好地了解其范围和驱动因素，以约束内陆水域对大气甲烷的贡献。
