To investigate how added nutrient nitrogen (N) and phosphorus (P) affect subarctic peatlands, we sampled peat soils from bog and fen type peatlands in the Northwest Territories, Canada, and measured CO₂ and CH₄ production rates by means of laboratory incubations. Our short-term experiments show that changes in nutrient concentrations in soil water can significantly affect microbial carbon cycling, suggesting the necessity of additional considerations of wildfire and permafrost thaw impacts on peatland carbon storage.