CAREER: Developing a Fire Ecology Framework for Soil Bacteria

职业：开发土壤细菌火灾生态框架

• 批准号: 2045864
• 负责人: Thea Whitman
• 金额: $ 99.31万
• 依托单位: University of Wisconsin-Madison
• 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: 2021-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2045864&HistoricalAwards=false
• 关键词: CAREER; Developing; Fire; Ecology; Framework

Wildfires cause major ecological as well as economic disturbances. They are increasing in frequency and severity in many regions of the world and burn hundreds of millions of hectares of land every year. The burned landscape results in large losses of carbon and nitrogen from ecosystems. Microorganisms in the soil play a critical role in the recovery of wildfire-affected ecosystems through their roles in cycling nutrients and their interactions with plants. The ecological impacts of wildfires on plant life are somewhat understood. This is not the case for soil microbes. The goal of this NSF CAREER project is to develop a fire ecology framework for bacteria, to improve understanding of why certain bacteria are “pyrophilous” – i.e., why they thrive following exposure to fire. The approach will draw on field research on northern forest wildfires and controlled prairie burns, laboratory experiments, and genetic sequencing. At its core, improving our understanding of bacterial response to fires will help underpin our understanding of how fires and changing fire regimes will affect the climate, an issue of great societal importance. This project will realize a myriad of broader impacts through its education goals, which are tightly integrated with each research goal. Undergraduates will be trained in the lab throughout the grant, working with the University of Wisconsin-Madison Undergraduate Research Scholars program, which will help support full participation of women and members of underrepresented groups in STEM fields. A podcast about fire ecology, developed in collaboration with undergraduates in the Life Sciences Communication program, and a new public outreach booth, “What happens belowground during a fire?”, will both help increase public scientific literacy and engagement with science and fire ecology.The proposed research will build on the PI’s prior results to strengthen and integrate a trait-based understanding of bacterial responses to fire. The overarching hypothesis is that fire survival will be most relevant shortly after wildfires (~1 year), fast growth will be relevant over longer timescales (~5 years), and pyrogenic organic matter degradation will be relevant over longer periods of time (~10 years). The first theme will address the patterns and traits of pyrophilous soil bacteria. In seeking to determine which bacteria and genetic characteristics are associated with burned soils, the research team will add a ten-year timepoint to a current one- and five-year timepoints in a 40-site wildfire field experiment, building toward what will ultimately become a long-term field study of boreal forest wildfires. In addition, the research team will apply an untargeted metagenomics-based approach at multiple time points to characterizing post-fire functional potential. Part of the proposed approach to strengthening a fire ecology framework for bacteria lies in experimentally investigating bacterial fire response through its separate components, such as heat tolerance. The second theme focuses on the interactive effects of temperature and drought on bacterial survival and post-fire carbon (C) mineralization. The approach will use laboratory experiments with bacterial isolates, intact soil cores, and gas flux tracing to determine the temperature ranges that pyrophilous bacteria can survive and whether prior drought stress affects bacterial survival of high temperatures and influences post-fire C mineralization rates. The third theme will aim to develop an integrative understanding of fire ecology for soil bacteria. Here, the research team will draw on current and emerging datasets and cross-domain collaborations to determine the relative importance of different traits in determining post-fire success of pyrophilous bacteria over time and across burn severities. Studies will compare how the traits that make bacteria successful fire-responders correspond to (or contrast with) equivalent strategies in other organisms. Overall, the project will advance our understanding of fundamental questions about the effects of fire on bacteria – critical players in post-fire ecosystem recovery. Undergraduate training will be coupled with mentorship training for a PhD student and a research technician, helping them become better future educators, themselves. To help support a globally competitive STEM workforce, the PI will develop new metagenomics tutorials for soil microbiology courses, which will provide cutting-edge bioinformatics skills to students. These tutorials will be developed with a postdoctoral researcher, who will also participate in UW-Madison teaching workshops, further helping to improve both STEM education and educator development.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.

野火造成重大的生态和经济干扰。在世界许多地区，森林火灾的频率和严重程度都在增加，每年烧毁数亿公顷的土地。被烧毁的景观导致生态系统中大量的碳和氮损失。土壤中的微生物通过其在养分循环中的作用及其与植物的相互作用，在受野火影响的生态系统的恢复中发挥着关键作用。野火对植物生命的生态影响已得到一定程度的了解。土壤微生物的情况并非如此。这个NSF CAREER项目的目标是为细菌开发一个火生态学框架，以提高对为什么某些细菌是“嗜火”的理解-即，为什么它们在暴露于火后会茁壮成长该方法将借鉴对北方森林野火和受控草原燃烧的实地研究、实验室实验和基因测序。其核心是，提高我们对细菌对火灾反应的理解将有助于巩固我们对火灾和火灾制度变化如何影响气候的理解，这是一个具有重大社会意义的问题。该项目将通过与每个研究目标紧密结合的教育目标实现无数更广泛的影响。本科生将在整个拨款期间在实验室接受培训，与威斯康星大学麦迪逊分校本科研究学者计划合作，这将有助于支持妇女和代表性不足的群体成员充分参与STEM领域。一个关于火灾生态学的播客，与生命科学交流项目的本科生合作开发，以及一个新的公共外展摊位，“火灾发生时地下会发生什么？"，都将有助于提高公众的科学素养和参与科学和火灾生态学。拟议的研究将建立在PI的先前结果，以加强和整合基于特征的细菌对火灾的反应的理解。总体假设是，火灾后不久（约1年），火灾生存将是最相关的，快速增长将是相关的较长的时间尺度（约5年），和热解有机物降解将是相关的较长的时间段（约10年）。第一个主题将解决的模式和特点的嗜热土壤细菌。为了确定哪些细菌和遗传特征与燃烧的土壤有关，研究小组将在40个地点的野火现场实验中，在目前的一年和五年时间点上增加十年时间点，最终将成为北方森林野火的长期实地研究。此外，研究小组将在多个时间点应用基于非靶向宏基因组学的方法来表征火灾后的功能潜力。提出的加强细菌火灾生态学框架的方法的一部分在于通过其单独的组成部分，如耐热性，实验研究细菌火灾反应。第二个主题的重点是温度和干旱对细菌生存和火灾后碳（C）矿化的相互作用。该方法将使用细菌分离株，完整的土壤芯和气体通量示踪的实验室实验，以确定嗜热细菌可以生存的温度范围，以及先前的干旱胁迫是否会影响高温下的细菌存活并影响火灾后的C矿化率。第三个主题旨在对土壤细菌的火生态学有一个全面的了解。在这里，研究小组将利用当前和新兴的数据集和跨领域合作来确定不同性状在确定嗜热细菌随时间和烧伤严重程度的火灾后成功方面的相对重要性。研究将比较使细菌成功应对火灾的特征如何与其他生物体的等效策略相对应（或形成对比）。总的来说，该项目将促进我们对火灾对细菌影响的基本问题的理解-火灾后生态系统恢复的关键参与者。本科生培训将与一名博士生和一名研究技术人员的导师培训相结合，帮助他们成为更好的未来教育者。为了帮助支持具有全球竞争力的STEM劳动力，PI将为土壤微生物学课程开发新的宏基因组学教程，为学生提供尖端的生物信息学技能。这些教程将与博士后研究人员一起开发，他们还将参加威斯康星大学麦迪逊分校的教学研讨会，进一步帮助改善STEM教育和教育工作者的发展。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。