Concentration and stable carbon isotopic composition of CO2 in cave air of Postojnska jama, Slovenia

Mandić, Magda; Mihevc, Andrej; Leis, Albrecht; Krajcar Bronić, Ines (2013) Concentration and stable carbon isotopic composition of CO2 in cave air of Postojnska jama, Slovenia. International Journal of Speleology, 42 (3). pp. 279-289. ISSN 0392-6672

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Abstract

Partial pressure of CO2 (pCO2) and its isotopic composition (δ13CairCO2) were measured in Postojnska jama, Slovenia, at 10 locations inside the cave and outside the cave during a one-year period. At all interior locations the pCO2 was higher and δ13CairCO2 lower than in the outside atmosphere. Strong seasonal fluctuations in both parameters were observed at locations deeper in the cave, which are isolated from the cave air circulation. By using a binary mixing model of two sources of CO2, one of them being the atmospheric CO2, we show that the excess of CO2 in the cave air has a δ13C value of -23.3 ± 0.7 ‰, in reasonable agreement with the previously measured soil-CO2 δ13C values. The stable isotope data suggest that soil CO2 is brought to the cave by drip water.

Item Type:	Article
Uncontrolled Keywords:	karst; cave; CO2 concentration; 13C of cave-air CO2; Postojnska jama
Subjects:	NATURAL SCIENCES > Geology
Divisions:	Division of Experimental Physics
Projects:	Project title Project leader Project code Project type Prirodni radioizotopi u istraživanju krških ekosustava i datiranju- Nada Horvatinčić 098-0982709-2741 MZOS
Depositing User:	Ines Krajcar Bronić
Date Deposited:	12 Oct 2016 10:58
URI:	http://fulir.irb.hr/id/eprint/3048
DOI:	10.5038/1827-806X.42.3.11

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