Elucidating the biogeochemical processes controlling natural source zone depletion (NSZD) of petroleum hydrocarbons in contaminated soils under dynamic redox conditions

微生物是所有生态系统的基础；它们调节碳、磷、氮和硫等营养物质以及许多微量元素的生物地球化学循环，对全球产生深远影响。它们是生物技术领域的关键参与者，也是二氧化碳、甲烷和一氧化二氮等温室气体的主要生产者之一。此外，土壤微生物群落可以帮助清理环境，例如通过降解原油泄漏释放的石油碳氢化合物(PH)污染物。鉴于据报道，加拿大60%的受污染场地受到PHS污染，模拟土壤中PH值生物降解的模型可以为对环境负责的能源部门提供必要的服务。因此，帝国石油公司的环境服务部门在埃克森美孚的全球支持下，与滑铁卢大学的生态水文学研究小组正在联手建立一个长期研究合作，重点是环境条件和过程的预测模型，控制受污染土壤中PHS的微生物降解。通过实验室实验和模型的结合，拟议的研究将侧重于确定不同的水文和气候驱动因素，特别是土壤冻结和融化以及地下水位波动，如何调节导致PH值自然降解的微生物反应途径。我们将开发一个全新的理论框架，将微生物群落内能量的生产和分配与土壤微生物在与环境相关但可变的条件下进行有助于PH值降解的化学转化的速率联系起来。由于重点是寒冷的气候条件，拟议的项目将增强加拿大能源行业缓解PH值污染对环境影响的能力。

Microorganism are the foundation of all ecosystems; they regulate the biogeochemical cycling of carbon, nutrients, such as phosphorus, nitrogen and sulfur, and many trace elements, with far-reaching global consequences. They are key players in the biotechnology sector and are among the main producers of greenhouse gases, including carbon dioxide, methane and nitrous oxide. In addition, soil microbial communities can help cleaning up the environment, for example by degrading petroleum hydrocarbon (PH) contaminants released by crude oil spills. Given that 60% of all contaminated sites in Canada are reportedly polluted with PHs, models that simulate PH biodegradation in soils can provide an essential service to an environmentally responsible energy sector. The Environmental Services units of Imperial Oil, with global support from ExxonMobil, and the Ecohydrology Research Group at the University of Waterloo are therefore joining forces to build a long-term research collaboration focused on the predictive modelling of the environmental conditions and processes controlling the microbial degradation of PHs in contaminated soils. Through a combination of laboratory experiments and modelling, the proposed research will focus on determining how variable hydrological and climatic drivers, specifically soil freezing and thawing and groundwater table fluctuations, modulate the microbial reaction pathways that are responsible for the natural degradation of PH. We will develop an entirely new theoretical framework that links the production and allocation of energy within microbial communities to the rates at which soil microorganisms carry out the chemical transformations that contribute to PH degradation, under environmentally relevant, but variable, conditions. With its emphasis on cold climate conditions, the proposed project will enhance the capacity of Canada's energy industry to mitigate the environmental impacts of PH pollution.