Impact of manganese-driven redox processes on groundwater quality and soil carbon cycling

锰驱动的氧化还原过程对地下水质量和土壤碳循环的影响

• 批准号: RGPIN-2020-05782
• 负责人: Hausladen, Debra
• 金额: $ 2.26万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740824
• 关键词: Impact; manganese; driven; redox; processes

The preservation of groundwater resources and the release of greenhouse gases represent critical environmental issues in Canada and worldwide. Soils play a central role in these challenges. The main goals of my research program in redox biogeochemistry are to understand groundwater contamination threats and to generate mechanistic understanding of mineral control on carbon sequestration in soils - the largest dynamic terrestrial carbon reservoir in the biosphere. By using a multidisciplinary approach, the proposed research program addresses two essential questions: (i) How do interactions among minerals (e.g., manganese oxides), microorganisms, and organic matter control redox-active geogenic contaminants which threaten groundwater quality? and (ii) What is the role of manganese oxides in soil carbon cycling? Manganese oxides are among the most reactive mineral phases in environmental systems and influence nearly every elemental cycle. Not only is Mn gaining recognition as an important control on both contaminant and carbon dynamics in aquatic and soil systems, but it is increasingly recognized as a contaminant of emerging concern in drinking water. The objective of this research program is to develop a better understanding of the dynamic cycling of Mn in soils, in order to provide safe drinking water and optimize carbon sequestration in soils. The proposed research addresses the following three axes: (1) Identifying physical and biogeochemical controls on Mn release in groundwater; (2) Evaluating competitive effect of Mn and C on geochemical processes controlling mobilization of geogenic As; and (3) Quantifying the abiotic transformation of complex organic C compounds by Mn oxides. The results will provide valuable information for the improved management of groundwater resources that are at risk of geogenic contamination. Surveying vital groundwater resources for native contaminants is critical to reduce public exposure and identify vulnerable areas for monitoring and management in order to prevent costly contaminant mobilization. In addition to helping allocate management resources more efficiently, the proposed research will provide valuable insight into controlling subsurface processes in order to minimize future groundwater contamination from natural sources. These results will provide water managers valuable information on whether aquifer geology or pedogenic and biogeochemical processes serve as better predictors of groundwater contamination. Finally, investigating the extent to which Mn oxides promote C mineralization will improve the accuracy of predicting how environmental changes and shifts in land-management may impact CO2 release. This improved understanding of mineral control on soil  cycling will be critical to ensure Canada reaches its 2030 emission reduction targets as committed to in the Paris agreement, especially in light of recent Québec legislation that calls for a complete ban of organic matter from landfills by 2020.

地下水资源的保存和温室气体的释放代表了加拿大和全球的关键环境问题。土壤在这些挑战中起着核心作用。我在氧化还原生物地球化学方面的研究计划的主要目标是了解地下水污染威胁，并对土壤中碳固存的矿物质控制产生机械理解，这是生物圈中最大的动态陆生碳储层。通过使用多学科的方法，拟议的研究计划解决了两个基本问题：（i）矿物质（例如锰氧化物），微生物和有机物控制氧化还原活性的地质污染物之间的相互作用如何威胁地下水质量？ （ii）锰氧化物在土壤碳循环中的作用是什么？锰氧化物是环境系统中最具反应性的矿物阶段之一，几乎影响每个元素周期。 MN不仅获得了水生和土壤系统中污染物和碳动力学的重要控制，而且越来越多地被认为是饮用水中新兴关注的污染物。该研究计划的目的是更好地了解土壤中MN的动态循环，以提供安全的饮用水并优化土壤中的碳固醇。拟议的研究涉及以下三个轴：（1）在地下水中MN释放时识别物理和生物地球化学控制； （2）评估MN和C对控制地球动员的地球化学过程的竞争作用； （3）量化Mn氧化物对复杂有机C化合物的非生物转化。结果将为有价值的信息提供有价值的信息，以改善有可能受到地球污染的风险的地下水资源的管理。对本地污染物的重要地下水资源进行调查对于减少公共暴露并确定弱势监测和管理区域至关重要，以防止昂贵的污染物动员。除了帮助更有效地分配管理资源外，拟议的研究还将为控制地下过程提供宝贵的见解，以最大程度地减少自然来源的未来地下水污染。这些结果将为水管理人员提供有关含水层地质或花梗的有价值信息，并且生物地球化学过程是更好地预测地下水污染的因素。最后，研究MN氧化物促进C矿化的程度将提高预测环境变化和土地管理的变化的准确性，这可能会影响CO2的释放。对矿产对土壤自行车的控制的了解将至关重要，对于确保加拿大在《巴黎协定》中承诺的降低目标达到其2030年的减少目标，尤其是鉴于最近的魁北克立法，该立法要求到2020年完全禁止垃圾填埋场。