Fate of methane in canals draining tropical peatlands.

Tropical wetlands and freshwaters are major contributors to the growing atmospheric methane (CH ₄ ) burden. Extensive peatland drainage has lowered CH ₄ emissions from peat soils in Southeast Asia, but the canals draining these peatlands may be hotspots of CH ₄ emissions. Alternatively, CH ₄ oxidation (consumption) by methanotrophic microorganisms may attenuate emissions. Here, we used laboratory experiments and a synoptic survey of the isotopic composition of CH ₄ in 34 canals across West Kalimantan, Indonesia to quantify the proportion of CH ₄ that is consumed and therefore not emitted to the atmosphere. We find that CH ₄ oxidation mitigates 76.4 ± 12.0% of potential canal emissions, reducing emissions by ~70 mg CH ₄ m ^-2 d ^-1 . Methane consumption also significantly impacts the stable isotopic fingerprint of canal CH ₄ emissions. As canals drain over 65% of peatlands in Southeast Asia, our results suggest that CH ₄ oxidation significantly influences landscape-scale CH ₄ emissions from these ecosystems.
Competing Interests: Competing interests The authors declare no competing interests.
(© 2024. The Author(s).)