CO2 dynamics and heterogeneity in a cave atmosphere: role of ventilation patterns and airflow pathways

Abstract Understanding the dynamics and distribution of CO 2 in subsurface atmosphere carbonate karst massifs provides important insights into dissolution precipitation processes, role systems global carbon cycle, use speleothems for paleoclimate reconstructions. We discuss long-term microclimatic observations a passage Postojna Cave, Slovenia, focusing on high spatial temporal variations p . show (1) that airflow through massif is determined by combined action chimney effect external winds (2) relationship between direction airflow, geometry pathways, position observation point explains observed Namely, terminal chamber passage, low uniform during updraft, when outside air flows to site system large open galleries. When reverses downdraft, fed inlets with diverse flow rates , which enter via small conduits fractures embedded -rich vadose zone. If outlets produces minimal mixing inflows, persistent gradients are formed. Such case chamber, where vertical up 1000 ppm/m downdraft. The results presented this work provide new composition demonstrate importance spatially distributed observations.