Article Dans Une Revue Geoscientific Instrumentation, Methods and Data Systems Année : 2025

A multiplexing system for quantifying oxygen fractionation factors in closed chambers

Clément Piel
Alexandru Milcu

Résumé

The study of isotopic ratios of atmospheric oxygen in fossilized air trapped in ice core bubbles provides information on variations in the hydrological cycle at low latitudes and productivity in the past. However, to refine these interpretations, it is necessary to better quantify the fractionation of oxygen in biological processes such as photosynthesis and respiration. We set up a system of closed biological chambers in which we studied the evolution of the elemental and isotopic composition of O 2 due to biological processes. To easily replicate experiments, we developed a multiplexing system which we describe here. We compared measurements of the elemental and isotopic composition of O 2 using two different measurement techniques: optical spectrometry (optical-feedback cavity-enhanced absorption spectroscopy, i.e., OF-CEAS technique), which enables higher temporal resolution and continuous data collection, and isotopic ratio mass spectrometry (IRMS) with a flanged air recovery system, thus validating the data analysis conducted through the OF-CEAS technique. As a first application, we investigated isotopic discrimination during respiration and photosynthesis. We conducted a 5 d experiment using maize (Zea mays L.) as the model species. The 18 O discrimination value for maize during dark plant respiration was determined as -17.8 ± 0.9 ‰ by IRMS and -16.1 ± 1.1 ‰ by optical spectrometer. We also found a value attributed to the isotopic discrimination of terrestrial photosynthesis equal to +3.2 ± 2.6 ‰ and by IRMS and +6.7 ± 3.8 ‰ by optical spectrometry. These findings were consistent with a previous study by Paul et al. (2023).

Mots clés

Fichier principal
Vignette du fichier
gi-14-91-2025.pdf (4.17 Mo) Télécharger le fichier
Origine Fichiers éditeurs autorisés sur une archive ouverte
Licence

Dates et versions

hal-05064904 , version 1 (13-05-2025)

Licence

Identifiants

Citer

Clémence Paul, Clément Piel, Joana Sauze, Olivier Jossoud, Arnaud Dapoigny, et al.. A multiplexing system for quantifying oxygen fractionation factors in closed chambers. Geoscientific Instrumentation, Methods and Data Systems, 2025, 14 (1), pp.91 - 101. ⟨10.5194/gi-14-91-2025⟩. ⟨hal-05064904⟩
90 Consultations
116 Téléchargements

Altmetric

Partager

  • More