Nutrient cycling and nutrient status control primary productivity, decomposition, plant community composition, and microbial community composition. Ombrotrophic bogs in Canada are often N and P co-limited, but increases in N addition through atmospheric deposition may lead to P limitation in these ecosystems. To study the effects of nutrient addition and nutrient limitation on peatland soil phosphorus pools, samples were taken from the long-term fertilization experiment at Mer Bleue Bog near Ottawa, ON. Samples were taken in 2022 following nearly twenty years of fertilizer application. These samples were subjected to a Hedley sequential fractionation to extract phosphorus along a gradient of biological availability. In unfertilized peat, most phosphorus was found at the extremes of the availability spectrum in either the available or highly recalcitrant pools. This contrasts with established patterns in mineral soils. In plots which received PK and NPK fertilizers, levels of both available phosphorus and highly recalcitrant phosphorus increased. In plots receiving N fertilization alone, available P levels decreased, which may indicate increased demand for P by plants and microorganisms when N status is high. In all plots receiving fertilizer, levels of highly recalcitrant phosphorus increased, which may indicate increased decomposition of peat. In addition, fertilization led to changes aboveground. Chamaedaphne calyculata leaves in plots receiving PK and NPK were enriched in phosphorus compared to C. calyculata leaves in unfertilized plots and plots receiving N alone. Further work regarding aboveground changes to the plant community in the fertilized plots will be carried out this summer.