A comprehensive framework for determining efficient bioremediation strategies for petroleum hydrocarbon-contaminated soils in cold regions**

加拿大北部地区有大量受石油烃污染的场地，生物修复被认为是清理这些场地的一种成本效益高的技术，即土壤微生物将有害的石油烃化合物转化为危害较小或无害的产品。然而，寒冷地区的低温可能会限制微生物的降解活性，因此需要在不同的温度条件下加热土壤或优化生物修复，以提高生物修复性能。通过向污染土壤中添加养分、水分和氧气的生物刺激可以增强北方地区微生物的活性。然而，目前尚不清楚生物刺激是否可以只针对碳氢化合物降解微生物群落，而不是其他可能不参与碳氢化合物生物降解的土壤微生物。本研究将系统地评估温度制度和生物刺激如何影响微生物群落组成和活性，以及添加营养物质的时机是否可以导致更有效的适应低温的生物修复操作。新的生物刺激方法的评估将根据从微观环境中收集的数据，以及使用不同场地土壤和在与场地有关的不同温度制度下运行的中试规模生物反应器。残留的、未降解的污染组分高于管制清理水平是一个共同的挑战。作为本研究的一部分，我们将评估土壤团聚体微观结构，特别是土壤微生物无法进入的土壤团聚体内部孔隙的比例，是否是生物修复终点的决定因素。这些研究将与工业伙伴魁北克水电公司密切合作进行，该公司对北部及其社区的可持续发展很感兴趣。本项目将培养本科生、博士生和博士后，研究北方地区有效生物修复的新方法

There are a significant number of petroleum hydrocarbon-contaminated sites in Canadian northern territories and bioremediation, where soil microbes transform hazardous petroleum hydrocarbon compounds to less hazardous or non-hazardous products, is considered a cost-effective technology for clean up of those sites. However, low temperatures in cold regions may limit microbial degradation activity, and thus soil heating or optimizing bioremediation for different temperature regimes is required for improving bioremediation performance. Biostimulation by addition of nutrients, moisture, and oxygen to the contaminated soils can enhance microbial activity in northern sites. However, it is unclear if biostimulation can be tailored to the hydrocarbon-degrading microbial community only, rather than other soils microbes that may not be involved in hydrocarbon biodegradation. This study will systematically assess how temperature regimes and biostimulation affect the microbial community composition and activity, and if the timing of nutrient addition could lead to more efficient bioremediation operations adapted to low temperatures. The assessment of new biostimulation approaches will be based on data collected from microcosms and as well as pilot-scale bioreactors operated using various site soils and at different temperature regimes relevant to the sites. Residual, un-degraded fractions of contamination that are above regulatory clean-up levels is a common challenge. As part of this study, we will assess if the soil aggregate micro-structure and in particular, the fraction of pores inside soil aggregates which are not accessible to soil microorganisms, is a determining factor for bioremediation endpoints. The studies will be conducted in close collaboration with the industrial partner, Hydro-Quebec, who is interested in the sustainable development of the north and its communities. Undergraduate, PhD and postdoctoral students will be trained in this project on new approaches for effective bioremediation in northern sites.**