Assessing the effects of the Oil Sands mining industry on wetlands plant physiology performance

FEDERICO MOLLARD; MARIE-CLAUDE ROY; A. LEE FOOTE

Toronto

Workshop; 37th Annual Aquatic Toxicology Workshop; 2010

Previous works in Oil Sands affected wetlands have found that some plants could withstand the salinity and toxicity of the processed waters and sediments. So it is critical to study the causes of such a tolerance in order to address the mechanisms involved. We propose that plants growing in affected wetlands can show measurable symptoms but an unaffected physiological performance compared to plants growing in reference wetlands. To test this hypothesis we choose Carex aquatilis as a wetland model plant for the Fort McMurray Region. A total of 5 natural, 5 directly affected by processed substrates or OSPW and 5 indirectly affected wetlands situated inside the Syncrude Canada and Suncor Energy Ltd. leases were selected. Plant photosynthesis, transpiration rates, stomatal conductance, and leaf fluorescence were measured. Our results show that critical physiological processes such as carbon assimilation and water economy were not reduced in plants from the affected wetlands when compared with reference plants. Moreover, processes related to leaf radiation use efficiency (Fv/Fm, Performance Index) were significantly increased in the affected wetlands. Results suggest that affected waters and substrates can positively affect some photosynthetic stages but they are fully compensated and have a non-significant impact in the entire carbon assimilation process. Results are in line with previous works in the Oil Sands industry where slightly positive effects of processed waters on Typha latifolia performance were found.