RAPID: The fate of methane during the Southern California Gas leak: Characterization of microbial consumption in soil, atmospheric transport, and ecosystem-level impacts.

美国国家科学基金会提供快速资金，用于研究2015-2016年南加州天然气泄漏期间和之后土壤中甲烷的微生物消耗。此次煤气泄漏是美国历史上规模最大的此类事件。甲烷是易燃气体。大气中甲烷浓度的增加可能会产生强有力的“温室效应”。该NSF快速奖将支持土壤中甲烷消耗微生物的特征、身份和活动，以应对气体泄漏，以更好地了解这场灾难对生态系统的影响。大气中甲烷泄漏的测量将与气体泄漏地点附近土壤微生物的测量进行比较，并追踪甲烷衍生碳随着时间的推移在土壤生态系统中的流动情况。这项时间进程研究中收集的数据将有助于未来对土壤相关微生物对全球甲烷循环的贡献进行建模。了解这一极端事件释放出的甲烷的命运对科学研究界和公共安全都有好处。甲烷中提取的土壤碳被认为会因为气体泄漏而显著增加。已知的以甲烷为能源和碳的微生物存在于不同的系统发育谱系中，土壤微生物群落(以及总体碳流)预计将因此次泄漏而发生可测量的变化。衡量这种变化的研究的具体组成部分包括：(1)详细监测甲烷和乙烷排放，包括泄漏期间和泄漏后的空气和土壤浓度。用于监测甲烷水平的方法将包括地面仪器、与NASA喷气推进实验室和加州理工学院教员合作从空气中进行的光谱测量、卫星观测和现场测量。(2)在天然气排放活跃期间和之后，定期和频繁地对土壤进行定向采样。(3)土壤微生物对甲烷富集的响应鉴定与表征。(4)评价与甲烷碳输入相关的土壤微生物群落和微真核生物的变化。这些后一组分的实验室方法包括高通量测序的微生物群落概况，基于RNA的活性分析；基于DNA的稳定同位素探查，用13CH4追踪甲烷衍生的碳进入当地微生物群落，以及在实验室收集的土壤的室内培养中测量甲烷代谢的速率。将定期对泄漏事件周围的地点和背景区域进行采样，以跟踪气体泄漏期间和之后的人口动态。结果将在合作的科学家之间分享，并通过预定的公开演讲、会议记录和出版物迅速传播。除了研究目标，该项目还将包括为一名本科生和一名研究生提供培训机会。

NSF RAPID funding is provided to study the microbial consumption of methane in soil during and following the 2015-2016 Southern California Natural Gas Leak. The gas leak was the largest such event in US history. Methane is flammable gas. Increasing concentrations of methane in the atmosphere can have a potent "greenhouse" effect. This NSF RAPID award will support the characterization, identity and activity of methane-consuming microorganisms in the soil in response to the gas leak, to better understand ecosystem-level impacts of the disaster. Atmospheric measurements of leaking methane will be compared to measurements of soil microorganisms near the site of the gas leak, as well as tracing the flow of methane-derived carbon through the soil ecosystem over time. The data collected in this time course study will assist with future modeling of the contribution of soil-associated microorganisms to global methane cycling. Understanding the fate of methane released from this extreme event has benefits to both the scientific research community and to public safety.Soil carbon derived from methane is hypothesized to measurably increase as a result of the gas leak. The known microorganisms that consume methane for energy and carbon occur within distinct phylogenetic lineages, and the soil microbial community (as well as overall carbon flow) is expected to measurably shift as a result of this leak. Specific components of the research to measure such changes include: (1) Detailed monitoring of methane and ethane emissions including air and soil concentrations, during and following the leak. Methods employed to monitor methane levels will include surface instrumentation, spectrometry measurements from air in collaboration with the NASA Jet Propulsion Laboratory and California Institute of Technology faculty, satellite observations, and field measurements. (2) Regular and frequent targeted sampling of soils during and following the period of active natural gas emission. (3) Identification and characterization of the soil microbial response to methane enrichment. (4) Assessment of changes in the soil microbial community and microeukaryotes associated with input of methane-derived carbon. Laboratory methods for these latter components include microbial community profiling with high throughput sequencing, RNA-based activity assays; DNA-based stable isotope probing with 13CH4 to trace methane derived carbon into the local microbial community, and rate measurements of methane metabolism in laboratory-based chamber incubations of collected soils. Sites surrounding the leak event and background areas will be sampled over a regular time course to track population dynamics during and following the gas leak. Results will be shared among collaborating scientists and rapidly disseminated through scheduled public talks, conference proceedings, and publications. In addition to the research goals, the project will include training opportunities for an undergraduate and a graduate student.