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Turning down the gas: what is the potential for microbial mitigation of methane leakage from soils

减少天然气用量：微生物缓解土壤甲烷泄漏的潜力有多大

基本信息

批准号：
2123356
负责人：
金额：
--
依托单位：
University of Nottingham
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-2123356
关键词：
Turning down gas what potential

项目摘要

The potential environmental impacts of hydraulic fracturing for shale gas extraction are a major concern for the general public, regulators and industry. One concern is the possibility of methane leakage. Methane is a greenhouse gas and a potential explosion hazard if it accumulates in enclosed spaces. Quantifying the impacts of methane leakage requires a good understanding of chemical, physical and biological processes involved in methane cycling in natural systems. The need for improved knowledge of natural biological processes in the critical zone, including soils, and their response to pollutants from industrial activities such as shale gas extraction was highlighted in NERC's recent ESIOS Science Plan. This project will use laboratory experiments, fieldwork and modelling to understand the microbial controls on source/sink behaviour of CH4 at a range of scales in the soil system. Hydrocarbon-contaminated soils will be used to establish the influence of environmental factors on CH4 transport and how biological, geochemical and physical factors affect surface emissions. The key aims are:- To assess the potential of the soil microbial community to respond to new or increased levels of methane leakage. Questions to be addressed include: How does synchronous methane production (methanogenesis) and oxidation (methanotrophy) affect transport and mean residence times of CH4 in soils? How rapid and sustained is the microbial response to increased methane concentrations? Is the response due to changes in microbial activity, number or community composition? - To identify, under laboratory conditions, the geochemical and physical conditions under which microbial activity in soils is critical for the prevention of methane escapes to the atmosphere. - To adapt and test techniques used in microbial oil and gas prospecting as potential tools for discriminating between leakages from shale gas operations, pre-existing hydrocarbon seeps and natural variations in biological methane cycling. Programme of Research:This project will use a range of microbiological, geochemical and gas transport techniques, coupled to numerical simulations of experimental and field data, in order to identify the environmental conditions that control surface methane emissions and to propose mitigation strategies. Training will be provided in molecular- and culture-based microbiology techniques, gas sampling using low-tension tube samplers (developed during recent research into the migration of 13C-labelled methane at UoN), gas chromatography, numerical modelling and model fitting methods (for gas transport and biogeochemistry).An initial period of 9-12 months will be spent mastering sampling, analytical and modelling methods and planning initial experiments and field sampling. Following this the student will begin a series of laboratory experiments to evaluate the impact of varying soil characteristics and conditions on microbial activity and in situ gas diffusion. These experiments will be carried out at UoN, with microbiological analysis being carried out at BGS. Concurrent with experimental work, field sampling will be carried out around known hydrocarbon seeps or abandoned wells to establish how variation in soil and environmental characteristics affects the transport of methane through soils and how pre-existing hydrocarbon leakage is reflected in microbial activity and community composition. BGS has access to several suitable sites and will lead the field sampling and subsequent microbiological analysis, with gas analysis carried out at UoN. Biogeochemical modelling using PHREEQC and in-house codes at BGS will be used to estimate the thermodynamic favourability of the observed changes in microbial communities; experimental and field data will be further simulated using a multiphase reactive transport modelling approach.

页岩气开采水力压裂对环境的潜在影响是公众、监管机构和行业的主要担忧。其中一个问题是甲烷泄漏的可能性。甲烷是一种温室气体，如果在封闭空间内积聚，可能会造成爆炸危险。要量化甲烷泄漏的影响，就需要很好地了解自然系统中甲烷循环所涉及的化学、物理和生物过程。NERC最近的ESIOS科学计划强调，需要更好地了解关键区的自然生物过程，包括土壤，以及它们对页岩气开采等工业活动产生的污染物的反应。该项目将利用实验室实验、实地考察和建模，了解微生物对土壤系统中各种尺度的CH 4源/汇行为的控制。将利用碳氢化合物污染的土壤来确定环境因素对甲烷迁移的影响以及生物、地球化学和物理因素如何影响地面排放。主要目标是：-评估土壤微生物群落对新的或增加的甲烷泄漏水平作出反应的潜力。要解决的问题包括：如何同步甲烷生产（甲烷）和氧化（甲烷营养）影响运输和平均停留时间的CH 4在土壤中？微生物对甲烷浓度增加的反应有多迅速和持续？这种反应是由于微生物活性、数量或群落组成的变化吗？- 在实验室条件下，确定土壤中微生物活动对防止甲烷逃逸到大气中至关重要的地球化学和物理条件。- 调整和测试用于微生物油气勘探的技术，作为区分页岩气作业泄漏、预先存在的碳氢化合物渗漏和生物甲烷循环自然变化的潜在工具。研究方案：本项目将使用一系列微生物、地球化学和气体迁移技术，并结合实验和实地数据的数值模拟，以确定控制地表甲烷排放的环境条件，并提出缓解战略。将提供基于分子和培养的微生物学技术、使用低压管采样器进行气体采样方面的培训（在最近对UoN的13 C标记甲烷迁移的研究中开发的）、气相色谱法、数值模拟和模型拟合方法（用于天然气运输和地球化学）。最初的9-12个月将用于掌握取样，分析和建模方法以及规划初步实验和实地取样。在此之后，学生将开始一系列的实验室实验，以评估不同的土壤特性和条件对微生物活性和原位气体扩散的影响。这些实验将在UoN进行，微生物分析将在BGS进行。在进行实验工作的同时，将在已知的碳氢化合物渗漏或废弃的威尔斯井周围进行实地取样，以确定土壤和环境特征的变化如何影响甲烷通过土壤的迁移，以及先前存在的碳氢化合物渗漏如何反映在微生物活动和群落组成中。BGS可以进入几个合适的地点，并将领导现场取样和随后的微生物分析，并在UoN进行气体分析。使用PHREEQC和BGS内部代码的生物地球化学建模将用于估计微生物群落中观察到的变化的热力学有利性;将使用多相反应运输建模方法进一步模拟实验和现场数据。