CAREER: Electrical Signals in Soils across Terrestrial and Aquatic Interfaces

陆地和海洋交界处的沿海土壤在捕获、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依赖于极端的水文扰动，如洪水、海平面上升和潮汐。由于极端水文事件的强度随着气候变暖而增加，有必要知道这些过程在沿海界面上发生的速度。然而，科学家经常依赖使用土壤岩心和传感器的直接离散测量来估计这些速率，这些测量无法捕捉空间变化，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，需要更好的方法来衡量这些过程，来自不同学科的更多科学家需要共同努力，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、激发极化和电导率，以更好地了解沿海界面上土壤条件的变化。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大环境测量的空间分辨率。该项目中拟议的研究将[1]评估自然电位和氧化还原电位的分布之间的关系以及两者如何随不同的土壤水分和有机质含量而变化，[2]研究有机质和土壤水分含量如何影响电流的迁移和存储，以及[3]评估渗透性的变化如何影响沿海界面土壤中电荷的存储。这项研究将涉及使用切萨皮克湾和伊利湖地区土壤的实验室实验和自动化长期重复实地测量的地球物理数据。这些稳健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，以研究沿海土壤的过程如何在空间上发生变化。本研究开发的将地球物理与生态研究相结合的多学科方法将用于培养高水平的本科生和研究生。还将采用案例研究方法，将地球物理学纳入托莱多大学的环境科学和生态学课程，并向公众公布。这将使未来的环境科学家能够使用和思考地球物理学以外的方法来扩大实验室和环境调查中通常使用的直接测量。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.