AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Microbes Thrive in Clouds and Interact with Physico-chemical Processes: From Field Observations to Atmospheric Models
PIERRE AMATO, Barbara Ervens, Raphaelle Peguilhan, Laurent Deguillaume, Anne-Marie Delort, ICCF, CNRS, Clermont Auvergne Université
Abstract Number: 178 Working Group: Bioaerosols
Abstract Cloud droplets offer aqueous environments to living airborne microorganisms in the atmosphere (~104 cells/mL of condensed water), where they maintain metabolic activity. Using next generation sequencing approaches (16S and 18S rRNA genes sequencing, whole metagenomes and metatranscriptomes), we specified microbial biological functioning in cloud water samples collected from puy de Dôme summit’s Atmospheric Observatory (1465 m asl; France). The results demonstrated a high taxonomic diversity in both prokaryotes and eukaryotes; the surviving organisms largely related to some abundant groups of bacteria affiliated with Alpha-, Beta- and Gamma-Proteobacteria, probably for a large fraction originating from vegetation. Metatranscriptomics specified their functioning and revealed intense interactions between cells and their direct environment in cloud water, with potential consequences for cloud chemical reactivity, including notably defense mechanisms against oxidants, cold and osmotic shocks, ions transport and binding, carbon and nitrogen compounds utilization (1). These, along with additional direct quantifications of biological aerosol mass, biological activity, biomarkers (ATP) and ice nucleation by biological particles in clouds and precipitation suggest a close interplay of biological, chemical, and microphysical processes. In order to estimate the amount of secondary biological mass that is formed by microbial processes in clouds, we combined the scarce data sets available for bacteria types and their activity in various ecosystems. We suggest that these processes might double primarily emitted bacteria in the atmosphere. In addition, we show that organic carbon processing by living microorganisms in clouds is probably negligible in terms of organic aerosol mass at the global scale. However, these processes might be important for the fate of specific chemical compounds. This research highlights the crucial need for experimental data for microbial aerosols, their diversity, dynamics and activity, and specifies directions for future investigations.
This research is currently funded by French Program ANR “Make Our Planet Great Again” MOBIDIC attributed to BE.
Reference: [1] Amato P, Besaury L, Joly M, Penaud B, Deguillaume L, Delort A-M. 2019. Metatranscriptomic exploration of microbial functioning in clouds. Sci Rep 9:4383.