Temperature Dependence of Methane Oxidation in Lakes: Global Trends and High-Temperature Inhibition in the Tropics

Lakes are important natural sources of atmospheric methane (CH4). However, only a small fraction of the CH4 produced in lakes reaches the atmosphere because of the high potential of aerobic CH4 oxidation (MOX). Although both CH4 production and oxidation are highly temperature dependent, the effect of temperature on MOX has received relatively less attention than that on CH4 production. Here, we combined MOX rate measurements from tropical lakes with published data from different climatic zones to assess the temperature dependence of MOX. We show a strong temperature dependence of MOX rates (activation energy ≈ 0.84 eV; Q10 ≈ 3.1). Notably, the activation energy and Q10 estimated for MOX are higher than those reported for northern aquatic systems but lower than those reported for methanogenesis in global lake sediments (0.96 eV and ∼4.0, respectively). This suggests that MOX has the potential to mitigate a substantial portion of warming-induced CH4 production in lakes. However, this pattern diverges in low-latitude lakes, where the MOX rates exhibit a negative correlation with temperature. Above a threshold of 28.0 °C, elevated temperatures inhibit MOX. Such inhibition of this biological CH4 sink in warm regions could generate previously unrecognized positive feedback between climate warming and CH4 emissions.