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.

石油溢油和/或原油管道破裂导致的碳氢化合物源区，导致持续的，长期的污染物污染含有可饮用地下水的含水层。该项目通过促进了解地球中碳氢化合物污染物的长期命运所需的科学来促进国家利益。传统上实施以定位煤油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污染物转化的进度的诊断信息，这些信息主要由地球上的微生物驱动。对随着时间的推移，在被石油污染的地点随着时间的推移，生物地球化学过程与地球物理信号之间的联系的这种探索可能会提供可靠地部署相对简单的地球物理测量系统所需的知识，以监测溢油的长期命运。就像医学成像使用人体非侵入性传感一样，污染物羽毛的非侵入性地球物理感觉最终可能用于理解地下地下无需钻入地下。一种无创的方法来监测人类影响的地下地球的健康，将限制人类和动物暴露于污染物中，并消除沿着侵入性钻探方法引起的途径的不必要的污染物运输。这项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基于现场的研究。该项目将吸引来自新泽西州北部城市，经济弱势社区的少数群体的地球科学学生。该研究的结果将与其他科学家和学生共享，通过举办与污染物羽毛相关的地球物理信号研讨会。过渡环境（例如低血和地下水位波动区（WTFZ））是生物地球化学热点，其中由补给事件驱动的水文过程会导致电子供体/受体混合物增强微生物代谢。由于这些系统的时空性和动态性质，使用水文，微生物和地球化学代理研究过渡环境中的水力地球化学过程具有挑战性。 WTFZ内发生的地球化学和微生物过程/转化在有机富含有机污染的位点会产生磁化率（MS）和自势（SP）电信号，这些信号显示出表明受充电事件和水位变化调节的证据。根据需要应用这些技术来研究现场位点上的水力地球化学过程的需要，了解导致测量的地球物理反应的生物地球化学因子的理解仍然不完整。该项目将在一个高度特征的地点进行跨学科研究，在该站点上，可以使用数十年的水文，地球化学和微生物数据来解释导致地球物理特征的驾驶机制。它将将本科教育与基础研究相结合，以提高人们对这种生物地球物理签名的起源的了解，以及如何通过可变的水文条件来调节它们。将进行支持实验室研究，以限制WTFZ内铁循环与生物地球物理特征之间的联系。将获取数据集以解决以下假设：[1]源区域中的水平驱动的铁循环引起的瞬时磁化率曲线； [2]烃源区域的磁化率变化是由于最初存在于沉积物上的铁氧氧化物的消耗而导致的。 [3]瞬态自势签名与溶解或气相电子受体的充值驱动的修改有关； [4]微生物介导的Fe（II）/Fe（III）氧化还原夫妇驱动生物地对肌，从而通过源区域的WTFZ引起异常的自我潜在特征。 假设将通过现场地球物理测量的结合来探索假设，这是悬挂在WTFZ区域中的钻孔和实验室模拟的沉积物数据包上的地球化学测量值。该奖项反映了NSF的法定任务，并通过使用基金会的知识优点和广泛的影响来评估NSF的法定任务。

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