Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 14841-14851, 2017
https://doi.org/10.5194/acp-17-14841-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
14 Dec 2017
H2O2 modulates the energetic metabolism of the cloud microbiome
Nolwenn Wirgot1, Virginie Vinatier1, Laurent Deguillaume2, Martine Sancelme1, and Anne-Marie Delort1 1Université Clermont Auvergne, CNRS, Sigma-Clermont, Institut de Chimie de Clermont-Ferrand, 63000 Clermont-Ferrand, France
2Université Clermont Auvergne, CNRS, Laboratoire de Météorologie Physique, 63000 Clermont-Ferrand, France
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. 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 a 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 the 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 cloud samples collected at the PUY station (1465 m a.s.l., France). The results support a strong correlation between ATP and H2O2 concentrations and confirm 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.


Citation: Wirgot, N., Vinatier, V., Deguillaume, L., Sancelme, M., and Delort, A.-M.: H2O2 modulates the energetic metabolism of the cloud microbiome, Atmos. Chem. Phys., 17, 14841-14851, https://doi.org/10.5194/acp-17-14841-2017, 2017.
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Short summary
This article highlights the interactions between H2O2 and microorganisms within the cloud system. Experiments performed in microcosms with bacterial strains isolated from clouds showed that H2O2 strongly impacted the microbial energetic state. The ATP depletion measured in the presence of H2O2 was not due to the loss of cell viability. The strong correlation between ATP and H2O2 based on the analysis of 37 real cloud samples confirmed that H2O2 modulates the metabolism of cloud microorganisms.
This article highlights the interactions between H2O2 and microorganisms within the cloud...
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