Fig 1.
A) and B) Locations of the Baradla and Béke Caves. C) Sampling site illuminated with a UV-lamp. Arrow marks the position of glass plate holder. D) Glass plate holder under dripping water. Glass plate is contoured with a black line and marked by an arrow. Photos by Ágnes Berentés.
Fig 2.
TSA contact plates inoculated with samples taken on May 29 after incubation at 20°C for 48 and 72 hours.
Red arrows point to the edge of the part of the plate pressed to the sample holder. White arrows point to the bacterial colonies, which follow this edge from the untreated habitat.
Fig 3.
Agar plates inoculated with samples taken May 29 (A) and February 20 (B, C) after incubation at 20°C, for 48, 72 hours and one week. C panel shows plates inoculated with original samples in the form of droplets. White arrows point to the bacterial colonies.
Table 1.
Stable carbon and oxygen isotope compositions (in ‰ relative to V-PDB) and clumped isotope data (CDES25°C) of the research samples in this paper.
Fig 4.
Scanning electron microscopic pictures of carbonates precipitated on glass plates.
A) Glass plate collected on January 13, 2020, control site. B) Glass plate collected on January 13, 2020, control site, calcite crystals partially covered by biofilm carbonate. C) Glass plate collected on January 13, 2020, UV-illuminated site. The white rectangle marks the area of Fig 4D. D) Glass plate collected on January 13, 2020, UV-illuminated site. Left side: resorbed calcite crystal. Right side: biofilm carbonate with bacterial forms. E) Glass plate collected on May 29, 2020, control site. F) Glass plate collected on May 29, 2020, UV-illuminated site.
Fig 5.
A) Calcite-water stable oxygen isotope fractionations of speleothems of the Baradla and Béke Caves. NU site: Nehézút, Baradla Cave, stalagmites NU-1, NU-2; VK site: Vaskapu site, Baradla Cave, stalagmites VK-1, VK-2 [16]; BNT-2: drill core of the Nagy-tufa flowstone [17]. Deposition rates are from Demény et al. [16]. B) Open circles: speleothems studied in this paper, dots: travertines [6]). Curves are from Daëron et al. [11] and Tremaine et al. [39], as in Fig 5A. Temperature uncertainties are smaller than the sample signs.
Fig 6.
Calcite-water stable oxygen isotope fractionations of farmed calcites of the Baradla Cave.
Empirical [11,39], experimental [40], and theoretical [41] curves are shown. Temperature uncertainties are smaller than the sample signs.
Fig 7.
Clumped isotope compositions as a function of precipitation temperature for farmed calcites.
Empirical and experimental „equilibrium” curves [8,9,11] are shown.
Fig 8.
Clumped isotope compositions as a function of calcite-water stable oxygen isotope fractionation values for farmed calcites and speleothems.