Collaborative Research: Biomass burning smoke as a driver of multi-scale microbial teleconnections

微生物存在于所有环境中，并在营养循环、气体交换以及与动植物的联系中发挥重要作用。然而，微生物从一个环境转移到另一个环境的方式还没有被很好地理解。每年，野地大火都会向大气中排放数百万吨的烟雾颗粒，这些颗粒可能会携带微生物。传统上，人们从对陆地生物群的直接影响和对大气的化学和物理影响的角度来研究野火，但烟雾作为生物扩散媒介的作用尚未被探索。草原是分布最广、燃烧最频繁的生态系统之一，因此这项研究将通过无人机飞入烟柱、燃烧实验和模拟自然条件的土壤培养来研究烟雾驱动的微生物在美国中部高草草原上扩散的影响。该项目使用一种综合的方法，以更好地了解烟雾对发生野火的所有环境中的人类、植物和动物健康的影响。全球野火的规模和严重程度不断增加，导致生物质燃烧烟雾与人类种群之间的相互作用增加，这使得这项研究与广泛的利益攸关方有关，包括那些对病原微生物的潜在运输感兴趣的人。除了指导三名博士后学者、一名研究生和本科生暑期实习生外，成果还将通过Konza Prairie LTER和Non地点的现有K-12和非正式学习计划传播给当地社区。生物质燃烧产生的烟雾中的微生物排放在数量和质量上都不同于从风力排放中观察到的生物气溶胶，这意味着野火可能是生态系统之间微生物遥控联系的一种全球相关但尚未量化的机制。为了测试烟雾如何驱动微生物群落生态，该项目将使用一种综合方法，在野外和实验室实验中比较烟源和烟汇微生物组合的组成和生存能力。在两年的时间里，将对草原反复规定的火灾期间的烟雾和颗粒沉积进行采样，以表征火灾行为、气象条件和烟雾中运输的微生物生存之间的关系。来自相似未焚烧地点的灭菌和未经处理的土壤将暴露在与已知微生物含量不同的烟雾剂量中，以比较选择、扩散和漂移对土壤微生物群落组成的相对影响。这些数据将被用来建立新的能力，通过对大气、化学传输和火灾-大气耦合模式中的微生物排放通量和微生物扩散进行参数化，来模拟烟雾微生物在尺度上的扩散。结果将深入了解随机过程与确定性过程在推动火灾干扰频繁的系统中微生物群落生态方面的相对重要性，而建模将能够预测与烟雾相关的微生物扩散的规模和影响。这项研究将为有关微生物基因流动、微生物病原体流行病学、植物病原体和气象过程的问题提供信息，并将扩大对火灾生态意义的基本理解。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和更广泛的影响审查标准进行评估，被认为值得支持。

Microbes are found in all environments and play essential roles in nutrient cycling, gas exchange, and through associations with plants and animals. However, the ways that microbes are transported from one environment to another are not well understood. Each year, wildland fires emit millions of tons of smoke particles into the atmosphere and these particles likely carry microbes with them. Traditionally, wildfires have been studied in terms of direct impacts to terrestrial biota and the chemistry and physics of the atmosphere, but the role of smoke as an agent of biological dispersal has yet to be explored. Grasslands are one of the most widespread and frequently burned ecosystems, so this research will examine the impacts of smoke-driven microbial dispersal in tallgrass prairies of the central United States using unmanned aerial vehicles flying into smoke plumes, combustion experiments and soil incubations that mimic conditions in nature. This project uses an integrated approach to better understand the consequences of smoke to human, plant, and animal health across all environments where wildland fire occurs. The increasing size and severity of global wildfires, leading to increased interaction between biomass burning smoke and human populations, make this research relevant to a wide range of stakeholders including those interested in the potential transport of pathogenic microbes. In addition to mentoring three post-doctoral scholars, a graduate student, and undergraduate summer interns, the results will be disseminated to local communities through existing K-12 and informal learning programs at the Konza Prairie LTER and NEON sites. Microbial emissions in smoke from biomass burning are both quantitatively and qualitatively different from the bioaerosols observed from wind-driven emissions, implying that wildland fire may be a globally relevant and yet-unquantified mechanism for microbial teleconnections among ecosystems. To test how smoke drives microbial metacommunity ecology, this project will use an integrated approach that compares the composition and viability of smoke source and sink microbial assemblages in field- and laboratory-based experiments. Smoke and particulate deposition during repeated prescribed fires in grasslands will be sampled over two years to characterize the relationships among fire behavior, meteorological conditions, and survival of microbes transported in smoke. Sterilized and untreated soils from similar, unburned sites will be exposed to contrasting dosages of smoke with known microbial content to compare the relative influence of selection, dispersal, and drift on soil microbial community assembly. These data will be used to build new capacity for simulating smoke microbial dispersal across scales by parameterizing microbial emission fluxes and microbial dispersion in atmospheric, chemical transport, and coupled fire-atmosphere models. Results will lend insight into the relative importance of stochastic vs. deterministic processes in driving microbial community ecology in systems where fire disturbances are frequent, while modeling will enable predictions of the scale and impact of smoke-related microbial dispersal. This research will inform questions about microbial gene flow, microbial pathogen epidemiology, phytopathogens, and meteorological processes, and will expand fundamental understanding of fire’s ecological significance.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.