Are bog plant/lichen tissue concentrations of Ca, Mg, K, and P affected by fugitive dust released from oil sands development in the Fort McMurray region of Alberta?

Abstract

Bogs are ombrotrophic, relying solely on atmospheric deposition for new inputs of elements. Increased element deposition through anthropogenic activities has the potential to alter nutrient availability, and hence ecosystem function, in bogs. Further, because of efficient element retention, bogs may function as effective monitors of element deposition. To assess the potential effects of particulate fugitive dust from oil sands development in Alberta, Canada, we quantified plant/lichen tissue Ca, Mg, K, and P concentrations in 6 bogs ranging from 12 to 77 km from the oil sands industrial center. Deposition of Ca and Mg, but not K or P, quantified using ion exchange resin collectors, to bogs decreased with distance from the oil sands industrial center. Concentrations of Ca and Mg, but not K or P, in tissues of lichens (Cladonia mitis, Evernia mesomorpha) and Sphagnum (S. capillifolium, S. fuscum) decreased with distance from the oil sands industrial center. Tissue Ca concentrations were positively correlated with growing season Ca and Mg deposition in all species except Vaccinium oxycoccos, Rhododendron groenlandicum, and Picea mariana; leaf Mg concentrations were positively correlated with growing season Mg deposition for all species except P. mariana. Tissue concentrations of K and P were not correlated with growing season K and P deposition. For each species, receptor modeling identified two distinct sources, one dominated by Ca and Mg, presumed to represent particulate fugitive dust from oil sands activities, and a second dominated by K and P, which may reflect tight internal cycling and upward translocation of K and P in peat and/or K and P deposition as particulates generated in wildfires. Increasing Ca2+ and Mg2+ deposition may acidify bog porewaters through cation exchange in peat.