Soil Nutrient Supply Rates in Natural and Reconstructed Wetlands of the Oil Sands Region.

The total mineable area of oil sands in western Canada is approximately 4800 km², of which about one third will need to be returned to functional wetlands.  The monitoring of these efforts will in itself be an enormous task.  Measurements of nutrient supply rate to PRS^TM probes (ion exchange membranes in a plastic support) were evaluated as a monitoring tool at natural and reconstructed sites in the oil sands region.   At non-disturbed sites, supply rates were consistently low for N, but varied widely for other nutrients.  Calcium and sulfur supply rates varied at both macro- and micro-scales, primarily reflecting hydrology.   Phosphorus and potassium supply rates varied among sites and due to fire events.  Iron and manganese supply rates were potential indicators of redox, provided sources of these elements were present.  At a recently reconstructed wetland site, nutrient supply rates were still dominated by salts transported from surrounding uplands.  Measurements of nutrient supply rate were sensitive to many factors influencing wetland function, but need to be integrated with other knowledge for monitoring purposes.