Hydrogeological control on carbon dioxide input into the atmosphere of the Chauvet-Pont d'Arc cave

A 23-year monitoring of CO₂ concentration (CDC) in the Chauvet-Pont d’Arc cave reveals that hydrogeological factors—specifically water infiltration and vegetation density—primarily control atmospheric CO₂ levels. The study found two distinct cave compartments with varying CDC values, showing seasonal and long-term fluctuations linked to water excess and surface conditions. While seasonal ventilation was ruled out, transient water infiltration correlated with reduced CO₂ flux in the larger compartment (A), whereas a more constant flux persisted in the smaller compartment (B). Carbon isotopic analysis supported the relationship between water input and CO₂ dynamics. The findings highlight concerns for the preservation of cave paintings due to increased CDC variability, driven by both hydrogeological changes and vegetation growth above the cave.

Bourges, F., Genty, D., Perrier, F., Lartiges, B., Régnier, É., François, A., Leplat, J., Touron, S., Bousta, F., Massault, M., Delmotte, M., Dumoulin, J.-P., Girault, F., Ramonet, M., Chauveau, C., & Rodrigues, P. (2020). Hydrogeological control on carbon dioxide input into the atmosphere of the Chauvet-Pont d’Arc cave. Science of the Total Environment, 716, 136844. https://doi.org/10.1016/j.scitotenv.2020.136844