| Summary: | Boreal peatlands serve as long-term carbon (C) sinks as well as a significant source of methane (CH4) to the atmosphere. However, peatlands are threatened by both natural and anthropogenic disturbances resulting in potential release of large amounts of C to the atmosphere. Linear disturbances such as seismic lines for oil and gas exploration constitute the largest area of disturbance in boreal Canada. The impact of seismic lines on peatland function, such as C cycling and hydrology, is not very well understood, although physical changes in topography and lack of tree re-establishment are well documented. This study used the closed chamber technique to measure growing season understory CH4 fluxes on the footprint of the seismic line disturbance and in adjacent intact peatlands and assessed environmental controls on CH4 dynamics across a poor fen and two wooded bogs near Peace River, AB. Seismic lines were significantly warmer and wetter providing ideal conditions for increased CH4 emissions at all sites. Methane emissions relative to natural plots were almost tripled in the bogs (261- 308 %) and close to double in fens (176 %). The persistence of the seismic lines and the elevated CH4 emissions is a cause for concern due to CH4 having a higher global warming potential compared to CO2. Results from this study will contribute to accurate greenhouse gas (GHG) reporting for anthropogenic disturbances in boreal peatlands, currently lacking for many disturbance types, as well as provide a scientific foundation for integrated land management practices and policies related to peatland restoration.
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