Peatland geoengineering: an approach to strengthen enzymic latch and impede carbon emissions in post-extracted peatlands?

Peatlands act as vast carbon (C) reservoirs by regulating decomposition over millennia. Unfortunately, drainage and peat extraction has affected functioning of peatlands by increasing organic matter decomposition. Previously, geoengineering tool as rewetting was used to reverse hydro-physical properties of peatlands that can limit C emissions. Also, another tool as phenolic addition was used on a small scale to test the enzymic latch process but ends up with contradictory results. Therefore, we aimed to combine rewetting with phenolic addition on a large scale to strengthen enzymic latch and to test how it can suppress enzyme activities, reduce peat decomposition, and limit greenhouse gas (GHG) emissions. In July 2021, an experiment was started at two post extracted peatlands that differ in age of industrial abandonment, at Rivière-du-Loup, Quebec, Canada. In both post extracted peatlands, rewetting along with three treatments (two phenolic additions — wood chip and ground roots, and one control) were applied. The current study will bring together fluxes of carbon dioxide (CO₂) and methane (CH₄) along with extracellular enzyme activities. Our preliminary results indicate that Verbois CO₂ flux was significantly lower than BDB peatland. Ecosystem respiration was not significantly different between rewetted and non-rewetted sections on both peatlands. Hydrolase enzyme activities were significantly lower at Verbois than BDB peatland. Phenolic addition resulted in significantly greater CO₂ flux than control plots on both peatlands. Initial results did not support enzymic latch strengthening by geoengineering. However, current study will be beneficial for unveiling the fate of enzymic latch mechanism in post-extracted peatland ecosystem.