title: High-resolution isotopic monitoring of cave air CO2.
abstract: BACKGROUND
  CO2is the main driver of many chemical processes in cave environments. Understanding CO2fluxes in a given cave system through monitoring campaigns has become a standard procedure in a wide variety of fields such as paleoclimatology or show cave management. However, conventional methods lack the resolution of isotopic data to capture many transient processes occurring in caves.
  
  
  METHODS
  A novel approach using isotope ratio infrared spectrometry (IRIS) to monitor cave air pCO2, δ13C and δ18O values in situ was tested and compared with conventional monitoring methods (handheld pCO2meter and discrete cave air samples for conventional isotope ratio mass spectrometry). This also involved the development of a field-deployable experimental setup to operate the equipment in rough cave environments.
  
  
  RESULTS
  Comparison between data obtained by means of a Thermo Fisher Scientific Delta Ray IRIS instrument shows overall good agreement with conventional monitoring methods in terms of pCO2and δ13C values. In addition, IRIS allows the δ18O values of cave air CO2to be measured.
  
  
  CONCLUSIONS
  IRIS allows identification and tracking of processes at various timescales ranging from transient visitor impact on the cave atmosphere to seasonal trends in cave ventilation. However, the need for an uninterrupted power supply (110/220 V AC) and the relatively large dimensions of the equipment (698 × 1092 × 704 mm, 80 kg) limit the number of caves where deployment of the instrument is feasible. Copyright © 2017 John Wiley & Sons, Ltd.
authors.affiliation: Institute of Geology, University of Innsbruck, Austria.
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0003-1738-5771
authors.initials: P
authors.lastname: Töchterle
authors.affiliation: Institute of Geology, University of Innsbruck, Austria.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Dublyansky
authors.affiliation: Thermo Fisher Scientific, Bremen, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: Stöbener
authors.affiliation: Thermo Fisher Scientific, Bremen, Germany.
authors.forename: Magda
authors.initials: M
authors.lastname: Mandić
authors.affiliation: Institute of Geology, University of Innsbruck, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Spötl