The importance of episodic ebullition methane losses from three peatland microhabitats: a controlled-environment study

Ebullition and episodic ebullition in particular, may be an important pathway for methane (CH₄) losses from northern peatlands. We quantified the importance of episodic ebullition using controlled environment laboratory incubations of samples of near-surface bog peat, focusing on how ebullition can be measured effectively and assessing the variation in CH₄ losses between microhabitats and seasons. The peat samples were collected from hollow and lawn microhabitats at two raised bogs: Longbridgemuir, southwest Scotland, and Cors Fochno, west Wales. We found that CH₄ fluxes excluding episodic ebullition differed between peatland microhabitats but not between summer and early autumn conditions. Conversely, episodic ebullition did not differ between microhabitat types but virtually stopped after the onset of early autumn conditions. Most strikingly, episodic ebullition was less than 3.3% of total CH₄ fluxes, and was therefore an insignificant mechanism of CH₄ loss from our peat samples.