Changes and controlling factors on atmospheric concentrations of carbon dioxide of Baeg-nyong Cave (Natural Monument No. 260), Pyeongchang-gun, South Korea, during a single autumn season

초록

The concentration of the atmospheric carbon dioxide (CO2) in the limestone cave has been studied in many foreign countries due to the importance of scientific aspects as well as sociocultural perspectives. However, despite the fact that there are large numbers of tourist caves in South Korea, the researches on the atmospheric CO2 in limestone caves are still insufficient. Here we report cave monitoring results on the concentrations of atmospheric CO2 from Baeg-nyong Cave (Natural Monuments of South Korea, No. 260), Pyeongchang-gun, South Korea, during a single autumn season. The monitoring program was established to investigate variations in multi-parameters of atmospheric environments for both of the inside (temperature, relative humidity, atmospheric CO2) and the outside (temperature, barometric pressure, rainfall amount and so on) of Baeg-nyong Cave from October 11th to November 16th, 2019. Total ranges of atmospheric CO2 concentrations in Baeg-nyong Cave fell into those of natural limestone caves for non-tourists in South Korea. It can be readily distinguished as the first and second half of the monitoring period based on their large (380 similar to 970 ppmv) and small (330 similar to 540 ppmv) variabilities, respectively. According to the weak correlations between CO2 concentrations and most of the potential sources of CO2, we speculated that the cave air CO2 has been originated constantly from soil zone through the diffusive air and drip water. Regardless of the sources, the high correlation coefficient (r=0.78) between CO2 concentrations and outside temperature strongly suggests that air density flows and cave ventilation processes are major controls on the variations in atmospheric CO2 concentrations of Baeg-nyong Cave. This result provides valuable information for the management and preservation of limestone caves in the temperate region although it is needed to carry out further researches.

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