Wetlands are found extensively throughout the Western Boreal Plain, a region under pressure because of disturbance by the oil and gas industries. To understand how wetland systems may respond to disturbance and set targets for reclamation efforts, it is necessary to understand natural variability in nutrient dynamics in the landscape. The purpose of this study was to characterize spatial variability in peatland nutrient (nitrogen, N, and phosphorus, P) dynamics in the Athabasca Oil Sands (AOS) region. N and P availability and net mineralization rates in the upper 10 cm layer of peat were examined during the peak growing season in five peatlands that fell along an apparent moisture gradient. N and P dynamics within and among the sites were related to water table position, peat moisture content and temperature. Phosphorus supply rates and total inorganic N pools and supply rates were generally elevated under wetter conditions, whereas nitrate (NO 3 À ) pools and supply rates and P pools did not vary along a moisture gradient. In general, net immobilization was observed at the wetter sites where nutrient pools were elevated and net mineralization was observed at drier sites where nutrient pools were lower. Nutrient transformation rates were most strongly driven by warmer temperatures. Nutrient availability and immobilization rates were anomalously high at one peatland (a disturbed fen with a semi-permanent road and decommissioned well pads). We suggest that reclamation and management practices should focus on regulating peatland hydrologic conditions, optimizing these for the most desirable nutrient levels for vegetation growth.

Peatlands of the Western Boreal Plains are under stress from oil and gas development and associated infrastructure such as road construction and removal. An improved understanding of nutrient cycling and atmospheric carbon dioxide (CO 2 ) exchange interactions in peatlands can assist in recommending best management practices to industry to minimize the ecohydrological disturbance footprint of road features. Peat nutrient (nitrogen, N, and phosphorus, P) supply, net mineralization, groundwater concentrations, and peatland-atmosphere CO 2 exchange rates were quantified within a poor fen bisected by a semi-permanent road located in the Athabasca Oil Sands region of Alberta, Canada, over one growing season. Results demonstrate that the road impeded groundwater movement across the site; however, water table and moisture differences were minimal, likely due to the unusually wet season. No clear impacts of the road on nutrient dynamics were observed, but subtle differences in productivity and respiration resulted in significantly lower net CO 2 sequestration (net ecosystem exchange) on the down-flow side of the road.Differences in vegetation composition between sides of the road were apparent and likely indicate longer-term moisture differences at the site. Elevated rates of productivity and respiration coincided with a seasonal change in the relative supplies of N and P (increased N : P ratios), suggesting that the relative availability of N versus P may be important to CO 2 fluxes in Western Boreal Plains peatlands. Collectively, these findings demonstrate the need to capture interactions between hydrology, ecology and nutrient biogeochemistry when evaluating peatland carbon cycling response to road disturbances across this region.