Northern peatlands contain a vast pool of soil carbon that may be vulnerable to atmospheric release under changing environmental conditions, potentially causing a positive feedback to the climate system (Frolking et al., 2011;Nichols & Peteet, 2019;Yu, 2012). The magnitude of carbon emissions and their mechanistic responses to changing environments are elusive due to the complexity of hydrologic and biogeochemical processes in peatland systems (Blodau, 2002). Methane (CH 4 ) is one of the key carbon forms leaving peatlands under anaerobic conditions. Given the high radiative warming potential of CH 4 compared to CO 2 (Neubauer & Megonigal, 2015), it is critically important to accurately predict future CH 4 emissions from global peatlands. Peatlands are typically formed over millennial timescales due to organic carbon inputs, long-term water saturation and low temperatures and thus store major amounts of terrestrial carbon (Yu, 2012). It is expected that hydrological and biogeochemical dynamics play important roles affecting CH 4 fluxes from peatlands, but many of these key processes are missing in current Earth system models (Bohn et al., 2015). Therefore, to build a better predictive capacity for CH 4 dynamics in peatlands, it is necessary to fully consider the processes and environmental conditions controlling CH 4 processes, particularly the