Effects of Redox Oscillations on Soil Clay Mineralogy and Colloid Dynamics

氧化还原振荡对土壤粘土矿物学和胶体动力学的影响

• 批准号: 418449917
• 负责人: Dr. Reiner Dohrmann
• 金额: --
• 依托单位: Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/418449917?language=en
• 关键词: Effects; Redox; Oscillations; Soil; Clay

Dynamic redox conditions are a major determinant of microbial activity and mineral reactivity in soils, but are poorly described by biogeochemical models of contaminant, nutrient, and carbon dynamics. In wetland and upland systems, redox conditions may change rapidly on a daily, weekly or seasonal basis due to changing moisture contents and water-table levels and associated biological oxygen production and demand; frequently resulting in distinct redox disequilibria. The temporal dynamics of hydrologic flow conditions can create pronounced soil redox gradients influencing mineral (trans)formation and reactivity and thus major and trace element cycling. However, the effect of alternating redox conditions on mineralogical changes and the dynamics of colloidal matter acting as "element shuttle" in soil are still poorly understood. Therefore, the aim of this research proposal is to assess (1) mineralogical responses to fluctuating redox conditions in soils, focusing on Fe(III)-oxide and phyllosilicate mineralogy, and (2) the dynamics of colloid formation and composition during multiple redox oscillations. The panned research will improve our knowledge on basic soil-forming processes linked to redox-induced mineral formation, transformation, and dissolution reactions, as well as processes controlling the soil-groundwater transfer of major and trace elements during recurring periods of soil saturation. It will thus contribute to a better understanding of soil responses to more distinct periods of soil wetting and drying expected in several Central European regions as a consequence of climate change.

动态氧化还原条件是土壤中微生物活性和矿物活性的主要决定因素，但污染物，养分和碳动力学的生态地球化学模型描述得很差。在湿地和高地系统中，由于水分含量和地下水位以及相关的生物氧气生产和需求的变化，氧化还原条件可能每天、每周或季节性地迅速变化;经常导致明显的氧化还原不平衡。水文流动条件的时间动态可以产生明显的土壤氧化还原梯度，影响矿物（反）形成和反应，从而主要和微量元素循环。然而，交替氧化还原条件对矿物学变化的影响和胶体物质在土壤中充当“元素穿梭”的动力学仍然知之甚少。因此，本研究建议的目的是评估（1）矿物学对土壤中氧化还原条件波动的响应，重点是Fe（III）-氧化物和页硅酸盐矿物学，以及（2）胶体形成和组合物在多次氧化还原振荡过程中的动态。这项研究将提高我们对与氧化还原诱导的矿物形成、转化和溶解反应有关的基本土壤形成过程的认识，以及在土壤饱和的反复出现期间控制主要和微量元素的土壤-地下水转移的过程。因此，它将有助于更好地了解土壤对气候变化造成的中欧几个区域预期出现的更明显的土壤湿润和干燥时期的反应。