ANTROPOGENNÍ OVLIVNĚNÍ OXIDU UHLIČITÉHO V JESKYNI V OBDOBÍ POTLAČENÉ VENTILACE (BALCARKA, MORAVSKÝ KRAS)
An anthropogenic impact on carbon dioxide (CO2-) concentrations was studied in the Balcarka Cave (Moravian Karst). The variables such as CO2 concentrations, cave/external temperatures, and number of visitors (attendance) were monitored in the Gallery Chamber and exterior with two-minute step during two-day monitoring campaign. For interpretation of the found data, a dynamic model was proposed. Modeling showed that the CO2 levels in the chamber under given conditions were controlled by the different CO2 concentrations in adjacent cave spaces and by the cave airflows driven by difference between the temperatures in cave and exterior, ΔT. The adjacent CO2 concentrations were (3.00–3.30)·10-2 mol m-3 (DAF ventilation mode) and 2.57·10-2 mol m-3 (UAF ventilation mode). There was identified a time shift between switching both the individual ventilation modes: the UAF mode switched over to DAF mode at non-zero temperature difference, ΔT = -2 °C. The overall natural net input of CO2 into the studied chamber was 8·10-5 mol s-1. The anthropogenic CO2 appeared as the peaks superimposed onto the natural CO2 concentrations. The peaks heights correspond to (i) number of visitors and (ii) period of their staying. The overall anthropogenic CO2 flux into the studied chamber varied from 8·10-5 to 3.47·10-3 mol min-1. This flux normalized to person number was 4·10-3 mol min-1.
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