Investigating biogeochemical controlled redox gradients in terrestrial and aquatic ecosystems

生物地球化学梯度的发展通常取决于微生物物理改变其化学环境并与其相互作用的能力。在许多情况下，微生物的活动将直接影响地表和地下水环境中的化学条件，控制营养物和污染物的命运。然而，我们面临着一些艰巨的挑战时，确定生物修复策略的选择。应用往往不是直截了当的，因为在许多情况下，人为干扰改变了当地景观，在确定补救最终目标时造成了问题。由此产生的问题是，什么样的基线或参考系统可以用来支持所选择的补救行动，并有望加以应用。哪些指标可用于研究有毒金属和有机污染物的流动性、循环性和生物有效性的长期和短期控制？例如，我们实验室的研究表明，在细菌存在下的矿物质溶解可以导致金属释放的特定途径，并将控制这些元素的命运，这取决于金属的溶解度以及细菌在其代谢过程中如何利用这一方面。我们的研究在实验室和应用工业应用中都观察到了这一点。该研究计划将继续专注于矿物系统/沉积物和细菌之间的相互作用，重点是阐明沉积物-水界面处细菌的还原和氧化形式所使用的机械化学途径。这项研究将是假设驱动的，并在实验室和实地项目中使用新的微生物和分析技术来解决这些研究问题。这些信息将用于支持自然和人为压力环境生态系统中生物地球化学循环的综合模型。此外，该计划内的研究将支持开发新的环境示踪剂。保持可持续的淡水资源直接关系到加拿大持续的社会经济成功（即农业，工业，人民和旅游业）。这项研究计划将提高我们对细菌如何控制自然生态系统中的金属释放以及受采矿业和人为投入影响的生态系统的理解。

The development of biogeochemical gradients is often dependent on a microorganism's ability to physically alter and interact with its chemical surroundings. In many cases the activity of microorganism will directly impact the chemical conditions in both surface and subsurface water environments controlling the fate of nutrients and contaminants alike. However we face several daunting challenges when defining the bioremediation strategy of choice. Often the application is not straightforward since in many cases the anthropogenic disturbance has altered the local landscape creating problems when defining the remedial end goal. Questions arise such as what are the baselines or reference systems that can be used and hopefully applied to support a remedial action of choice. What indices can be used to study the long term and short-term controls on the mobility, cycling, and bioavailability of toxic metals and organic contaminants? For example, studies in our lab have shown that mineral dissolution in the presence of bacteria can lead to specific pathways of metal release and will control the fate of these elements dependent on the metals solubility and how the bacteria utilize this aspect during its metabolism. Our research has observed this in both laboratory and applied industrial applications. This research program will continue to focus on the interactions between mineral systems/sediments and bacteria with an emphasis on elucidating mechanistic chemical pathways used by reducing and oxidizing forms of bacteria at the sediment water interface. This research will be hypothesis driven and use novel microbial and analytical techniques in both laboratory and field based programs to address these research questions. The information will be applied to support comprehensive models for biogeochemical cycling in natural and anthropogenic stressed environmental ecosystems. In addition research within this program will support the development new environmental tracers to track. Maintaining sustainable freshwater resources are directly tied to Canada's continued socio-economic success (i.e. agriculture, industry, people, and tourism). This research program will enhance our understanding of how bacteria control metal release in natural ecosystems as well as those impacted by mining sector and anthropogenic inputs.