Is bog water chemistry affected by increasing N and S deposition from oil sands development in Northern Alberta, Canada?

Nitrogen and sulfur emissions from oil sands operations in northern Alberta, Canada have resulted in increasing deposition of N and S to the region’s ecosystems. To assess whether a changing N and S deposition regime affects bog porewater chemistry, we sampled bog porewater at sites at different distances from the oil sands industrial center from 2009 to 2012 (10-cm intervals to a depth of 1 m) and from 2009 to 2019 (top of the bog water table only). We hypothesized that: (1) as atmospheric N and S deposition increases with increasing proximity to the oil sands industrial center, surface porewater concentrations of NH(4)(+), NO(3)(−), DON, and SO(4)(2−) would increase and (2) with increasing N and S deposition, elevated porewater concentrations of NH(4)(+), NO(3)(−), DON, and SO(4)(2−) would be manifested increasingly deeper into the peat profile. We found weak evidence that oil sands N and S emissions affect bog porewater NH(4)(+)-N, NO(3)(−)-N, or DON concentrations. We found mixed evidence that increasing SO(4)(2−) deposition results in increasing porewater SO(4)(2−) concentrations. Current SO(4)(2−) deposition, especially at bogs closest to the oil sands industrial center, likely exceeds the ability of the Sphagnum moss layer to retain S through net primary production, such that atmospherically deposited SO(4)(2−) infiltrates downward into the peat column. Increasing porewater SO(4)(2−) availability may stimulate dissimilatory sulfate reduction and/or inhibit CH(4) production, potentially affecting carbon cycling and gaseous fluxes in these bogs. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10661-021-09555-4.