Geologic exploration activities increase methane emissions from boreal peatlands.

In recent years the preservation and restoration of peatlands has been pushed to the forefront of climate change mitigation plans. Unfortunately, boreal peatlands in Canada are threatened by extensive industrial exploration and extraction of natural resources. Many of these anthropogenic disturbances include linear pathways for geologic exploration of petroleum and mineral resources, also known as seismic lines. Apart from reported changes in peatland micro-topography and the lack of tree re-establishment, seismic lines crossing peatlands impact ecohydrological conditions leading to alterations in carbon (C) cycling. However, few studies have quantified the extent of these changes, resulting in a lack of reporting of these impacts in estimates of anthropogenic greenhouse gas emissions.

 

This study took place in northern Alberta (Canada), across wooded bogs and a wooded fen. The primary objective was to evaluate the impact of seismic lines on CH₄ and CO₂ fluxes in the field and under laboratory conditions. CH₄ fluxes and the net ecosystem exchange of CO₂ (NEE) was measured over two growing seasons from 48 paired plots across the bogs and fen using the closed chamber technique, while 144 incubation jars with replicate samples were deployed in the lab. Corresponding data on environmental variables including peat temperature, vegetation cover, biomass and water table depth were recorded as well.

 

Seismic lines crossing peatlands significantly increased CH₄ emissions, almost doubling in fens (176%) and tripling in bogs (261–308%) compared to their surrounding peatland areas. This was driven by warmer and wetter conditions on the line as well as a vegetation shift to more productive species. These results are essential for accurate greenhouse gas reporting as well as restoration planning and design.