METACLOUD is a scientific project launched in October 2021 aiming at quantifying and modeling the utilization of C1 compounds (formaldehyde) by microorganisms in clouds, funded by the French National Research Agency (ANR). This is led by the BIOMETA research group at ICCF (Institut de Chimie de Clermont-Ferrand, UMR6296 CNRS-UCA, France), in close collaboration with LaMP/OPGC (Laboratoire de Météorologie Physique/Observatoire de Physique du Globe de Clermont-Fd, France).
Omics methods (metabolomics, fluxomics, transcriptomics) are used for quantifying metabolic fluxes in cloud water and evaluating their impacts on formaldehyde’s fate. Atmospheric chemistry models are developed while microbial functioning in these unexplored environments is specified.
Scientific hypotheses and objectives
METACLOUD focuses on characterizing the ability of the cloud microbiota to metabolize C1 compounds (Figure 1). This is motivated by the following considerations:
(a) Radical chemistry causes successive oxidation of organic matter into C1 compounds, which are thus found in cloud water at high concentrations (tens of µM) (Deguillaume et al., 2014);
(b) Methylotrophic microorganisms (capable of utilizing C1 compounds) are present and active in clouds (Vaïtilingom et al., 2013; 2011; Husárová et al., 2011; Šantl-Temkiv et al., 2013; Amato et al., 2017; Amato et al., 2019);
(c) Key C1 metabolic routes can be specifically studied in details using commercially available 13C-formaldehyde, which is a central intermediate of C1 metabolism (Chistoserdova and Kalyuzhnaya, 2018).
The scientific hypotheses of METACLOUD are based on previous observations:
(a) the metabolic pathways expressed by cloud microorganisms are likely to be modulated by H2O2 exposure and the presence/absence of UV light (Wirgot et al., 2017) so that different biochemical reactions are expected to occur during the day compared to at night; (b) Formaldehyde is a key intermediate both in cloud radical chemistry and in many C1 biological pathways (Figure 1). Hence, these metabolic routes and their modulations are expected to impact overall chemical reactivity in clouds.
The outcome of C1 metabolism depends on the metabolic abilities of microbial strains, which can be impacted by environmental conditions. Microorganisms can degrade C1 compounds to produce energy (dissimilation routes) and/or to build up biomass (assimilation pathways).
The main objective of METACLOUD is to improve our fundamental understanding of the processes occurring in clouds, its chemistry and biodiversity, with a focus on defining the role of microbial metabolism in C1-driven cloud chemistry. To achieve this goal, newly acquired data on cloud microbiome metabolic networks under two contrasted atmospheric scenarios (day versus night), with the dynamics of the system revealed by the “meta-fluxome” maps, will be obtained through 13C tracking investigations. Then, these newly considered processes of cloud biogeochemistry, in particular C1 compound biodegradation rates, will first be integrated into a numerical tool to generate a novel, holistic model of cloud chemistry.
Working program
The 3-year work program is organized in 5 experimental tasks, coordinated by A.-M. Delort (ICCF).
References cited:
Amato, P., Joly, M., Besaury, L., Oudart, A., Taib, N., Moné, A. I., Deguillaume, L., Delort, A.-M., and Debroas, D.: Active microorganisms thrive among extremely diverse communities in cloud water, PLOS ONE, 12, e0182869, https://doi.org/10.1371/journal.pone.0182869, 2017.
Amato, P., Besaury, L., Joly, M., Penaud, B., Deguillaume, L., and Delort, A.-M.: Metatranscriptomic exploration of microbial functioning in clouds, 9, 4383, https://doi.org/10.1038/s41598-019-41032-4, 2019.
Chistoserdova, L.: Modularity of methylotrophy, revisited, 13, 2603–2622, https://doi.org/10.1111/j.1462-2920.2011.02464.x, 2011.
Deguillaume, L., Charbouillot, T., Joly, M., Vaïtilingom, M., Parazols, M., Marinoni, A., Amato, P., Delort, A.-M., Vinatier, V., Flossmann, A., Chaumerliac, N., Pichon, J. M., Houdier, S., Laj, P., Sellegri, K., Colomb, A., Brigante, M., and Mailhot, G.: Classification of clouds sampled at the puy de Dôme (France) based on 10 yr of monitoring of their physicochemical properties, Atmos. Chem. Phys., 14, 1485–1506, https://doi.org/10.5194/acp-14-1485-2014, 2014.
Husárová, S., Vaïtilingom, M., Deguillaume, L., Traikia, M., Vinatier, V., Sancelme, M., Amato, P., Matulová, M., and Delort, A.-M.: Biotransformation of methanol and formaldehyde by bacteria isolated from clouds. Comparison with radical chemistry, Atmospheric Environment, 45, 6093–6102, https://doi.org/10.1016/j.atmosenv.2011.06.035, 2011.
Šantl-Temkiv, T., Finster, K., Hansen, B. M., Pasic, L., and Karlson, U. G.: Atmospheric methane oxidation by airborne methanotrophic bacteria at cloudlike conditions, 00000, 2013.
Vaïtilingom, M., Deguillaume, L., Vinatier, V., Sancelme, M., Amato, P., Chaumerliac, N., and Delort, A.-M.: Potential impact of microbial activity on the oxidant capacity and organic carbon budget in clouds, PNAS, 110, 559–564, https://doi.org/10.1073/pnas.1205743110, 2013.
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.