Carbon dioxide and methane exchange dynamics from boreal peatland soils under controlled moisture and substrate amendments

This data were generated to investigate both the initial and longer-term effects of substrate additions on total soil respiration in Canadian peatlands and to evaluate how moisture conditions and peatland type (bog or fen) interact with these substrates to influence carbon dioxide and methane exchange. The dataset comprises carbon dioxide and methane flux measurements from 96 laboratory incubation jars monitored over a 511-day experimental period. Peat samples were collected from four Canadian peatland sites (Hudson Bay Lowland, Seba Beach, Brazeau, and Spongy Lake) between September 2022 and February 2024. The experiment was conducted under controlled room-temperature conditions, where peat vertical structure was standardized and samples were isolated from live plant communities and natural environmental variability. Gas concentrations were measured using a LI-COR LI-7810 carbon dioxide and methane trace gas analyzer. During each measurement event carbon dioxide and methane concentrations were recorded over a three-minute interval. Fluxes were calculated using the ideal gas law, accounting for chamber headspace volume, atmospheric pressure, and temperature, and were normalized to the initial carbon content of the peat to enable comparison across treatments. In addition to flux values, the dataset includes raw concentration slopes, model fit statistics, environmental conditions (temperature and relative humidity), jar configuration details, substrate treatments, moisture treatments, site codes, peatland classification (bog or fen), and replicate identifiers. This dataset is associated with the publication “Substrate addition alters carbon dioxide and methane exchanges in incubation experiments of Canadian peatland soils” (Davies et al., 2026; doi: 10.1029/2025GB008896) and supports research on peatland carbon cycling, greenhouse gas emissions, priming mechanisms, and the biogeochemical consequences of infrastructure development and organic matter additions in boreal and subarctic ecosystems.