Wetland CH4 Flux Temperature Hysteresis Explained by Substrate Availability and Microbial Activity

Wetland CH4 Flux Temperature Hysteresis Explained by Substrate Availability and Microbial Activity

February 23rd, 2021
Using a mechanistic ecosystem model, ecosys, to demonstrate that static temperature relations cannot accurately predict wetland CH4 production and emission rates due to substrate-mediated microbial and abiotic interactions.
The Objective: 

To demonstrate that static temperature relations cannot accurately predict wetland CH4 production and emission rates due to substrate-mediated microbial and abiotic interactions.

New Science: 

This study ran the ecosys model across Alaskan and Swedish sites to examine mechanisms leading to the observed apparent CH4 emission hysteresis to temperature.

The Impact: 

Substantial intra-seasonal variations in apparent CH4 emission temperature dependence are observed and modeled in Alaskan (Utqiaġvik) and Swedish tundra, challenging the fixed temperature relations prescribed in most terrestrial BGC models. The findings demonstrate the uncertainty of inferring CH4 emission or production rates from temperature alone and highlight the need to represent microbial and abiotic interactions in wetland biogeochemical models.

Observed CH4 flux temperature hysteresis at Stordalen and Utqiaġvik (top panels) is explained by substrate availability and methanogen activity (bottom panel).