Treffer: Investigating the Atmospheric Microbial Ecosystem Through Theory, Bioenergetics, and Numerical Modeling: A Breath of Fresh Air for Aeromicrobiology.

The atmosphere may constitute the Earth's largest microbial ecosystem, yet it remains the least understood. While microorganisms can persist and may even thrive in the polyextremes of the Earth's atmosphere, it is still unknown whether the atmosphere sustains an active microbial community. Despite growing awareness of the role of the aeromicrobiome in shaping global biogeography, epidemiology, and climate, fundamental questions about its metabolic activity and ecological significance remain unanswered. Here, we outline how theoretical approaches and numerical modeling tools provide powerful avenues to investigate the atmospheric microbial ecosystem, offering unique insights that complement experimental and observational‐based studies and can overcome many of the challenges they face. We consider frameworks that integrate (a) theoretical considerations for microbial metabolism across a range of catabolic and anabolic processes, (b) microbial physiology and metabolic states, (c) thermodynamics and bioenergetics, (d) the chemical and physical conditions of the atmosphere and bioaerosols, (e) transport and residence time of microorganisms, and (f) bottom‐up and top‐down approaches. Theory and modeling‐based investigations into the aeromicrobiome can generate and test theory and model‐informed hypotheses, formulate mechanistic explanations of biological processes and observations, and inform targeted sampling strategies and experimentation. Together, these approaches bring us closer to determining whether the Earth's atmosphere is a true ecosystem—that is, a metabolically active community of organisms interacting with each other and with the environment. Advances in aeromicrobiology research brought about by theory and modeling can reveal significant insights into global biogeography, biogeochemical cycles, climate processes, and the limits for life. Plain Language Summary: The atmosphere presents numerous challenges to microorganisms including low temperatures, aridity, UV radiation, and low nutrient availability. Despite research demonstrating that microorganisms can tolerate and even grow under these conditions, we still do not have a clear picture of whether the Earth's atmosphere constitutes an active microbial ecosystem. Here, we outline how theoretical and numerical modeling tools provide new avenues to investigate microorganisms in the atmosphere. We evaluate theoretical bases of microbial metabolism (the set of processes used by microorganisms to obtain energy from nutrients), thermodynamics, and bioenergetics (how microbes transform energy), in context with the chemical, physical, and biological composition of the atmosphere, to outline how theory and modeling‐based investigations can generate and refine hypotheses, sampling strategies, and experimentation; evaluate the capacity of the atmosphere to sustain life and support a microbial ecosystem; and assess how biological processes influence the Earth's atmosphere. Advances in aeromicrobiology research brought about by theory and modeling can reveal significant insights into global biogeography, biogeochemical cycles, climate processes, and the limits for life in planetary atmospheres. Key Points: Aerobiology research is hindered by several technical challenges facing experimental studies, sampling, and monitoring strategiesTheoretical approaches and numerical modeling tools provide powerful avenues to investigate the atmospheric microbial ecosystemAnticipated theoretical advances include evaluating the survival and growth of atmospheric microbial cohorts on different metabolites [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geophysical Research. Biogeosciences is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)