Foredragsholder: Dr. Freyria, McGill University
Natural attenuation involves a number of processes that impact the fate of oil spilled into the environment. It includes processes such as evaporation, dissolution, dispersion, photodegradation and biodegradation. Biodegradation is a particularly important process because it results in the permanent removal of the oil components through the action of microorganisms, mainly bacteria, that are able to use many of the compounds present in oil as a food source. Understanding the advantages and limitations of oil biodegradation in the natural environment can enable us to exploit this process in the clean-up of oil spills. Our knowledge of the natural attenuation potential of hydrocarbons in marine beach sediments in Arctic environments is currently severely lacking at an international level and especially in the Canadian context. While our work during the previous DFO funded Oceans Protection Plan Multi-Partner Research Initiative (DFO-MPRI) allowed us to determine that some hydrocarbon biodegradative microbial populations exist in typical Northwest Passage beach sediments, our understanding of how they will respond to an oil spill is still unclear and our initial attempts to develop bioremediation strategies using biostimulation with N and P did not considerably enhance rates of hydrocarbon biodegradation. Hydrocarbon biodegradative activities were relatively slow given the very harsh Arctic in situ conditions, especially the cold ambient temperatures. There is also considerable interest in characterizing in more detail the role of natural attenuation of oil in these ecosystems. Natural attenuation includes a variety of chemical, physical and biological processes that act to reduce the concentration of oil products once spilled in the environment. In the Canadian context, there are large areas of land that are remote and not very accessible, should an oil spill occur. This includes most of the Canadian Arctic, mainly marine and coastline, as well as much of our more northern land areas where rail lines and pipelines may be present. Continued work is required to extend the surveying of these at-risk environments to determine whether there are indigenous oil degrading microbes and whether the local conditions are suitable for supporting their activity. In addition, identifying factors that could enhance degradation activity would be beneficial and facilitate any clean-up operations following a spill. Isolating, characterizing, and identifying key hydrocarbon degrader organisms in Arctic beach sediment environments may also shed light on the specific conditions and bioremediation treatments that could enhance their biodegradative activities and could potentially be used for bioaugmentation of contaminated beaches. Determination of in situ oil biodegradation capacity of spilled oil washing up on beaches in Canada is a key aspect of developing relevant oil spill remediation approaches for the different oceans surrounding Canada. This is especially true for the Canadian Arctic Ocean where global warming is resulting in the opening of the Northwest Passage to a broad and sustained increase in anthropogenic activities (i.e., shipping both Canadian and international) and the exploitation and transportation of offshore Arctic oil reserves in the Canadian high Arctic. All these elements are putting the marine areas in and around the Northwest Passage at an elevated risk for an oil spill which would have a serious impact on sustenance in local communities. Inevitably, some of these oils will wash up on Arctic beaches significantly increasing ecosystem risks to both marine and terrestrial systems. The proposed in situ beach microcosms will determine the hydrocarbon bioremediation potential on a representative Arctic beach under actual Arctic environmental conditions (biological, physical and chemical) and the effectiveness of proposed treatments on degrading the oil. This project will potentially provide data leading to optimal bioremediation treatments for hydrocarbon contaminated Arctic beaches in the future and provide a policy framework for implementing remediation of such sites.