Collaborative Research: Investigating how transient electrical and magnetic signals relate to changes in recharge-driven redox state and iron mineral transformations

合作研究：研究瞬态电信号和磁信号如何与充电驱动的氧化还原状态和铁矿物转变的变化相关

• 批准号: 2212998
• 负责人: Estella Atekwana
• 金额: $ 11.64万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-10-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2212998&HistoricalAwards=false
• 关键词: Collaborative; Research; Investigating; how; transient

Hydrocarbon source zones resulting from oil spills and/or crude oil pipeline ruptures result in persistent, long-term source of contamination of the aquifers that store potable groundwater in the Earth. This project serves the national interest by advancing the science needed to understand the long-term fate of hydrocarbon contaminants in the Earth. Geophysical tools that have been traditionally implemented to locate oil reservoirs and mineral deposits will be used to explore how geophysical signals provide diagnostic information on the progress of contaminant transformations that are largely driven by microbes in the Earth. This exploration of the linkages between biogeochemical processes and geophysical signals over time at an oil contaminated site may provide the knowledge needed to reliably deploy relatively simple geophysical measurement systems to monitor the long-term fate of oil spills. In the same way that medical imaging uses non-invasive sensing of the human body, non-invasive geophysical sensing of contaminant plumes might ultimately be used to understand the subsurface Earth without the need to drill into it. A non-invasive approach to monitoring the health of the human-impacted subsurface Earth would limit exposure of humans and animals to contaminants and negate unwanted transport of contaminants along pathways caused by invasive drilling methods. The research will be performed by undergraduate students performing field-based research in collaboration with government scientists from the United States Geological Survey (USGS). The project will engage minority undergraduate geoscience students from urban, economically disadvantaged neighborhoods in northern New Jersey. Results of the research will be shared with other scientists and students by running a workshop on geophysical signals associated with contaminant plumes. Transitional environments such as hyporheic and water table fluctuation zones (WTFZ) are biogeochemical hotspots where hydrologic processes driven by recharge events cause electron donor/acceptor mixtures that enhance microbial metabolism. Hydro-biogeochemical processes in transitional environments are challenging to study using hydrological, microbial and geochemical proxies due to the spatio-temporal and dynamic nature of these systems. Geochemical and microbial processes/transformations occurring within the WTFZ at organic-rich contaminated sites give rise to magnetic susceptibility (MS) and self potential (SP) electrical signals that show evidence of being regulated by recharge events and changes in water level. Understanding of the biogeochemical factors resulting in the measured geophysical responses, as needed to apply these techniques to investigate hydro-biogeochemical processes at field sites, remains incomplete. This project will pursue interdisciplinary research at a highly characterized site where decades of hydrological, geochemical and microbiological data are available to interpret the driving mechanisms causing geophysical signatures. It will integrate undergraduate education with basic research to advance understanding of the origins of such biogeophysical signatures and how they are regulated by variable hydrologic conditions. Supporting laboratory studies will be performed to constrain the linkages between iron cycling and biogeophysical signatures within the WTFZ. Datasets will be acquired to address the following hypotheses: [1] Transient magnetic susceptibility profiles result from hydrologically-driven iron cycling in the source zone; [2] Magnetic susceptibility changes in hydrocarbon source zones result from the consumption of iron-oxyhydroxides initially present on the sediments; [3] Transient self potential signatures are associated with recharge-driven modifications of dissolved or gas phase electron acceptors; [4] A microbial-mediated Fe(II)/Fe(III) redox couple drives a biogeobattery causing an anomalous self potential profile through the WTFZ in the source zone. Hypotheses will be explored by a combination of field geophysical measurements, in situ geochemical measurements on sediment packets suspended in boreholes and laboratory simulations of the WTFZ zone.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.

石油泄漏和/或原油管道破裂造成的碳氢化合物源区导致地球上储存饮用水地下水的含水层受到持续、长期的污染。该项目通过推进了解地球碳氢化合物污染物的长期命运所需的科学来服务于国家利益。传统上用于定位油藏和矿藏的地球物理工具将用于探索地球物理信号如何提供有关主要由地球微生物驱动的污染物转化进展的诊断信息。随着时间的推移，对石油污染地点生物地球化学过程和地球物理信号之间联系的探索可能会提供可靠部署相对简单的地球物理测量系统以监测石油泄漏的长期命运所需的知识。就像医学成像使用人体的非侵入式传感一样，污染物羽流的非侵入式地球物理传感最终可能用于了解地下地球，而无需钻入地下。监测受人类影响的地下地球健康状况的非侵入性方法将限制人类和动物对污染物的暴露，并消除侵入性钻探方法引起的污染物沿着路径的不必要的运输。该研究将由本科生与美国地质调查局 (USGS) 的政府科学家合作进行实地研究。该项目将吸引来自新泽西州北部城市、经济贫困社区的少数族裔地球科学本科生。研究结果将通过举办与污染物羽流相关的地球物理信号研讨会与其他科学家和学生分享。过渡环境，如低流区和地下水位波动区 (WTFZ) 是生物地球化学热点，其中由补给事件驱动的水文过程导致电子供体/受体混合物增强微生物代谢。由于这些系统的时空和动态性质，使用水文、微生物和地球化学代理来研究过渡环境中的水文生物地球化学过程具有挑战性。 WTFZ 内富含有机物污染场地发生的地球化学和微生物过程/转化会产生磁化率 (MS) 和自电位 (SP) 电信号，这些信号显示出受补给事件和水位变化调节的证据。对于应用这些技术来研究现场水文生物地球化学过程所需的导致测量的地球物理响应的生物地球化学因素的理解仍然不完整。该项目将在一个高度特征化的地点进行跨学科研究，那里有数十年的水文、地球化学和微生物数据，可以解释引起地球物理特征的驱动机制。它将本科教育与基础研究结合起来，以增进对此类生物地球物理特征的起源以及它们如何受到可变水文条件的调节的理解。将进行支持性实验室研究，以限制 WTFZ 内铁循环与生物地球物理特征之间的联系。将获取数据集来解决以下假设：[1] 瞬态磁化率剖面是由源区水文驱动的铁循环产生的； [2] 烃源区磁化率的变化是由于沉积物中最初存在的羟基氧化铁的消耗所致； [3] 瞬态自电位特征与溶解或气相电子受体的再充电驱动的修饰有关； [4] 微生物介导的 Fe(II)/Fe(III) 氧化还原对驱动生物电池，在源区的 WTFZ 中产生异常的自电位分布。 将通过结合现场地球物理测量、对钻孔中悬浮沉积物包的原位地球化学测量以及 WTFZ 区域的实验室模拟来探索假设。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优势进行评估，被认为值得支持以及更广泛的影响审查标准。

项目成果

Microbially Induced Anaerobic Oxidation of Magnetite to Maghemite in a Hydrocarbon‐Contaminated Aquifer

• DOI: 10.1029/2021jg006560
• 发表时间: 2022-04
• 期刊: Journal of Geophysical Research: Biogeosciences
• 作者: L. Ohenhen;J. Feinberg;L. Slater;D. Ntarlagiannis;I. Cozzarelli;M. Rios-Sanchez;C. Isaacson;Alexis Stricker;E. Atekwana