Natural organic matter (NOM) consists of a complex and heterogeneous mixture of naturally occurring compounds that are involved in many important biogeochemical processes such as metal complexation, pollutant fate and transport, nutrient cycling, redox reactions and also acts as a source of energy for the microbial community. The observed structural heterogeneity of NOM, in terms of molecular formulae, encodes (i) source materials, (ii) transforming processes and (iii) their controlling environmental and biological factors. It is therefore necessary to better understand and identify the underlying processes that control organic matter dynamics.
Biogeochemical studies conducted at the molecular-level have significantly improved our understanding of carbon dynamics and highlighted the importance of high resolution analytical techniques in biogeochemical sciences. High (or Ultrahigh) resolution mass spectrometry (MS) techniques (like Fourier-transform Orbitrap MS or Fourier-transform ion cyclotron resonance MS) coupled to soft ionization techniques now allow the identification of thousands of intact individual molecular formulae from complex mixtures like dissolved organic matter (DOM).
This seminar will present two recent applications of high resolution mass spectrometry applied to biogeochemical studies.
 Maria, E.; Crançon, P.; Lespes, G.; Bridoux, M. 2019. Spatial Variation in the Molecular Composition of Dissolved Organic Matter from the Podzol Soils of a Temperate Pine Forest. ACS Earth and Space Chemistry, 3, 8, 1685-1696.
 Bianco, A.; Deguillaume, L.; Vaîtilingom, M.; Nicol, E.; Baray, J-L.; Chaumerliac, N.; Bridoux, M. Molecular characterization of cloud water samples collected at the Puy de Dôme (France) by Fourier transform ion cyclotron resonance mass spectrometry. Environ. Sci. Technol.
 Bianco, A.; Deguillaume, L.; Chaumerliac, N.; Vaîtilingom, M. ; Wang, M. ; Delort, A-M. ; Bridoux, M. 2019. Effect of endogenous microbiota on the molecular composition of cloud water: a study by Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Scientific Report, 9, 10, 7663.
 Bianco, A.; Riva, M.; Baray, J-L.; Ribeiro, M.; Chaumerliac, N.; George, C.; Bridoux, M.; Deguillaume, L. 2019. Chemical Characterization of Cloudwater Collected at Puy de Dôme by FT-ICR MS Reveals the Presence of SOA Components. ACS Earth and Space Chemistry, 3, 10, 2076-2087.