CAREER: Electrical Signals in Soils across Terrestrial and Aquatic Interfaces

陆地和海洋交界的沿海土壤在捕获、储存、转化和释放碳、氮、沉积物、水和能量方面发挥着重要作用。这些界面上物质的转化和交换取决于极端的水文扰动，如洪水、海平面上升和洪水。随着气候变暖，极端水文事件的强度增加，有必要了解这些过程沿沿海界面发生的速度。然而，科学家们经常依靠使用土壤岩心和传感器的直接离散测量来估计这些速率，这无法捕捉空间变化，因此很难使用模型来预测这些地区将如何受到气候变化的影响。因此，需要更好的方法来测量这些过程，并且需要更多来自不同学科的科学家一起工作来利用他们不同的方法。该项目将推进地球物理成像技术的使用，包括自然电势、诱导极化和电导率，以更好地了解沿海界面土壤条件的变化。该项目还将指导环境科学和生态学专业的学生如何使用这些地球物理方法来扩展环境测量的空间分辨率。本项目拟开展的研究将[1]评估自然电位和氧化还原电位的分布关系及其随土壤水分和有机质含量的变化；[2]研究有机质和土壤水分含量如何影响电流的迁移和储存；[3]评估渗透率变化如何影响沿海界面土壤中电荷的储存。这项研究将包括使用来自实验室实验的地球物理数据，以及对切萨皮克湾和伊利湖地区土壤进行长期、重复的自动化实地测量。这些强大的数据集将与土壤氧化还原电位、水分含量、基质电位、盐度和土壤呼吸的直接测量相结合，研究沿海土壤过程的空间变化。本研究将地球物理学与生态学研究相结合的多学科方法，用于培养高年级本科生和研究生。还将采用个案研究方法，将地球物理学纳入托莱多大学的环境科学和生态学课程，并向公众提供。这将使未来的环境科学家能够使用和思考超越地球物理学的方法，以扩大实验室和环境调查中通常使用的直接测量。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Soils along coastal interfaces where the land and ocean meet play important roles in capturing, storing, transforming, and releasing carbon, nitrogen, sediments, water, and energy. The transformation and exchange of materials at these interfaces depend on extreme hydrological disturbances such as flooding, sea level rise, and seiches. As the intensity of extreme hydrological events increases with a warming climate, there is a need to know the rate at which these processes take place along coastal interfaces. However, scientists often rely on direct discrete measurements using soil cores and sensors to estimate these rates, which are incapable of capturing spatial changes, making it hard to use models to predict how these areas will be affected by changes in climate. Hence, better ways to measure these processes are needed, and more scientists from different disciplines need to work together to leverage their different approaches. This project will advance the use of geophysical imaging techniques, including natural electrical potential, induced polarization, and electrical conductivity, to better understand changes in soil conditions along coastal interfaces. This project will also mentor environmental science and ecology students on how to use these geophysical methods to expand the spatial resolution of environmental measurements. The proposed research in this project will [1] assess the relationship between the distribution of natural electric potential and redox potential and how both change with different soil moisture and organic matter contents, [2] investigate how organic matter and soil moisture contents affect the migration and storage of electric current, and [3] assess how changes in permeability affect the storage of electrical charges within soils along coastal interfaces. This study will involve using geophysical data from laboratory experiments and automated long-term, repeated field measurements on soils at both the Chesapeake Bay and Lake Erie regions. These robust datasets will be combined with direct measurements of soil redox potential, moisture content, matric potential, salinity, and soil respiration to study how processes along coastal soils change spatially. The multidisciplinary approach of integrating geophysics with ecological studies developed in this research will be used to train upper-level undergraduate and graduate students. A case-study approach will also be used to include geophysics in the environmental science and ecology curriculum at the University of Toledo and made publicly available. This would equip future environmental scientists to use and think of methods beyond geophysics for scaling laboratory and direct measurements typically used in environmental investigations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.