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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=753831
• 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.

地下水资源的保护和温室气体的释放是加拿大和全世界的关键环境问题。土壤在这些挑战中发挥着核心作用。我的氧化还原生物地球化学研究项目的主要目标是了解地下水污染威胁，并形成对土壤中碳封存矿物控制的机制理解——土壤是生物圈中最大的动态陆地碳库。通过使用多学科方法，拟议的研究计划解决了两个基本问题：（i）矿物质（例如氧化锰）、微生物和有机物之间的相互作用如何控制威胁地下水质量的氧化还原活性地质污染物？ (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反应性最强的矿物相之一，几乎影响每个元素循环。锰不仅被认为是水生和土壤系统中污染物和碳动态的重要控制剂，而且越来越被认为是饮用水中新出现的污染物。该研究计划的目的是更好地了解土壤中锰的动态循环，以提供安全的饮用水并优化土壤中的碳封存。拟议的研究涉及以下三个轴：（1）确定对地下水中锰释放的物理和生物地球化学控制； (2) 评价Mn和C对控制地源As动员的地球化学过程的竞争作用； (3) 量化锰氧化物对复杂有机碳化合物的非生物转化。 研究结果将为改善面临地质污染风险的地下水资源管理提供有价值的信息。调查重要地下水资源中的原生污染物对于减少公众暴露和确定脆弱区域进行监测和管理至关重要，以防止代价高昂的污染物流动。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，以最大限度地减少未来来自自然资源的地下水污染。这些结果将为水资源管理者提供宝贵的信息，说明含水层地质学或土壤成土和生物地球化学过程是否可以更好地预测地下水污染。最后，研究锰氧化物促进碳矿化的程度将提高预测环境变化和土地管理转变如何影响二氧化碳排放的准确性。加深对土壤循环中矿物质控制的了解对于确保加拿大实现《巴黎协定》中承诺的 2030 年减排目标至关重要，特别是考虑到魁北克最近的立法要求到 2020 年全面禁止垃圾填埋场中的有机物。