10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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H2O2 Modulates the Energetic Metabolism of the Cloud Microbiome
ANNE MARIE DELORT, Nolwenn Wirgot, Virginie Vinatier, Martine Sancelme, Laurent Deguillaume, Université Clermont Auvergne
Abstract Number: 711 Working Group: Bioaerosols
Abstract Chemical reactions in clouds lead to oxidation processes driven by radicals (mainly HO●, NO3● or HO2●) or strong oxidants such as H2O2, O3, nitrate and nitrite. Among those species, hydrogen peroxide plays a central role in the cloud chemistry by driving its oxidant capacity. In cloud droplets, H2O2 is transformed by microorganisms which are metabolically active [1]. Biological activity can therefore impact the cloud oxidant capacity. The present article aims at highlighting the interactions between H2O2 and microorganisms within the cloud system.
First, experiments were performed with selected strains studied as reference isolated from clouds in microcosms designed to mimic the cloud chemical composition, including the presence of light and iron. Biotic and abiotic degradation rates of H2O2 were measured and results showed that biodegradation was the most efficient process together with photo-Fenton process. H2O2 strongly impacted the microbial energetic state as shown by adenosine triphosphate (ATP) measurements in the presence and absence of H2O2. This ATP depletion was not due to the loss of cell viability.
Secondly, correlation studies were performed based on real cloud measurements from 37 clouds samples collected at the puy de Dôme station (1465 m a.s.l., France). The results supported a strong correlation between ATP and H2O2 concentrations and confirmed that H2O2 modulates the energetic metabolism of the cloud microbiome. The modulation of microbial metabolism by H2O2 concentration could thus impact cloud chemistry, in particular the biotransformation rates of carbon compounds and consequently can perturb the way the cloud system is modifying the global atmospheric chemistry [2].
References: [1] M. Vaïtilingom, L. Deguillaume, V. Vinatier, M. Sancelme, P. Amato, N. Chaumerliac, A.-M Delort, Proceeding of National Academy of Science USA, 110, (2013), 559. [2] N. Wirgot, V. Vinatier, L. Deguillaume, M. Sancelme, A.-M. Delort, Atmospheric Chemistry and Physics, 17, (2017), 14841. https://doi.org/10.5194/acp-17-14841-2017.