The research paper by, Ms Athena Pookkattu, Dr Latika Patel, Dr Sarath Chandra Gowd Kesani along with Research Scholar Ms Rashmi Singh from the Department of Environmental Science and Engineering, titled Temperature Dependence of Methane Oxidation in Lakes: Global Trends and High-Temperature Inhibition in the Tropics, presents groundbreaking findings that reveal how rising temperatures influence MOX rates. The findings underscore the importance of understanding MOX in the context of climate change, especially as it pertains to mitigating the greenhouse gas emissions from freshwater ecosystems. Explore the critical insights that can shape the future environmental policies and conservation efforts as mentioned by our student and alumni.
Brief Abstract:
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.
Explanation in Layperson’s Terms:
The study examines how aerobic methane (CH₄) oxidation—an important natural sink for a potent greenhouse gas—responds to temperature variations across global lakes. By integrating new data from tropical lakes with published global datasets, the study reveals a strong temperature dependence of methane oxidation. Notably, it identifies high-temperature inhibition of methane oxidation in tropical lakes, suggesting a potential increase in methane emissions under future warming scenarios
Collaborations:
Shoji D. Thottathil − Department of Environmental Science and Engineering, SRM University-AP, Amaravati 522 240 Andhra Pradesh, India.
Athena Pookkattu − Department of Environmental Science and Engineering, SRM University-AP, Amaravati 522 240 Andhra Pradesh, India.
Latika Patel − Department of Environmental Science and Engineering, SRM University-AP, Amaravati 522 240 Andhra Pradesh, India; Geosciences Division, Physical Research Laboratory, Ahmedabad 380 009 Gujarat, India.
Rashmi Singh − Department of Environmental Science and Engineering, SRM University-AP, Amaravati 522 240 Andhra Pradesh, India.
Sarath C. Gowd − Department of Environmental Science and Engineering, SRM University-AP, Amaravati 522 240 Andhra Pradesh, India; Swedish Centre for Resource Recovery, University of Borås, Borås 503 32, Sweden