Seasonal variation of radon and CO2 in the Važecká Cave, Slovakia

The continuous monitoring of 222Rn activity concentration, CO2 concentration, and microclimatologic parameters (internal air temperature and relative humidity) in the Važecká Cave (Northern Slovakia) is being carried out at three monitoring stations, namely, Gallery, Lake Hall, and Entrance Hall. Radon activity concentration and CO2 concentration exhibited a clear annual variation. The daily average of radon concentration ranged 1300–27 700 Bq/m3 at the Lake Hall station and 3600–42 200 Bq/m3 at the Gallery station. Radon reached its maximum in the summer months, from June to September. The annual maximum of CO2 concentration is registered approximately one month later than radon maximum. The annual variation of radon and CO2 is controlled by the seasonal change of ventilation regime associated with the seasonal variation of the difference between the temperature measured inside the cave and the atmospheric temperature

Speleogenesis in a lens of metamorphosed limestone and ankerite: Ochtiná Aragonite Cave, Slovakia

The Ochtiná Aragonite Cave (Western Carpathians) represents an unique natural phenomenon. It originated under particular lithological and hydrogeological conditions of the Ochtiná Karst in which several isolated lenses of Paleozoic crystalline limestone (marbles), partly metasomatically altered to ankerite, are enclosed by phyllites. Meteoric water seepage through non-carbonate rocks dissolved limestone and caused the oxidation of ankerite to Fe oxyhydroxides. Carbon dioxide produced during ankerite oxidation enhanced limestone dissolution. The maze cave consists of parallel fault-controlled linear passages and chambers interconnected by transverse horizontal passages. Phreatic and epiphreatic solution morphologies resulted from slowly moving or standing water. These include flat ceilings (Laugdecken), facets (planes of repose, Facetten), lateral notches, convection ceiling cupola-shaped depressions, and spongework-like hollows. Flat ceilings were developed in several altitude positions, each of them probably closely below the slightly oscillated water table. Primary phreatic cupola-shaped depressions, truncated by flat ceilings, represent relics of the oldest cavities (pre-Quaternary? to Early Pleistocene). Inward-sloping smooth facets were not developed only in passages with flat ceilings, but also in the passages and halls with a vaulted ceiling. The asymmetrical shape of cusped depressions above the facets were documented in detail by a high-resolution cave topography with terrestrial laser scanning and digital photogrammetry. Middle–Late Pleistocene accumulation phases, identified by magnetostratigraphy of cave sediments and U-series dating of speleothems, are associated with phreatic and later epiphreatic development. The deposition on the bottom bedrock began before 1.8 Ma. The Brunhes/Matuyama boundary (0.773 Ma) and Jaramillo magnetozone (0.990–1.071 Ma) were recorded in the profile in the Oválna chodba Passage. Slow depositional rate (~0.09 cm/kyr) calculated from magnetostratigraphy resulted from slow water movement in confined conditions in marbles completely enclosed by phyllites and no direct relation to the surface. Only occasionally turbid water was loaded in extremely fine-grained infiltration material and autochthonous Fe oxyhydroxides. The depositional rate in Mn-rich layer was much slower (~0.03 cm/kyr). Additional U-series dating confirmed that old aragonite generations (with ages about 500–450 ka and 143–121 ka) were partly corroded by repeated floods during Late Pleistocene humid episodes. Aragonite younger than 13.5 ka is not corroded

The occurrence of coliform bacteria in the cave waters of Slovak Karst, Slovakia

The diversity and abundance of coliform bacteria (taxonomically enterobacterias), an important quality water indicator, were determined for four representative caves in Slovak Karst: Domica Cave, Gombasecká Cave, Milada Cave and Krásnohorská Cave. Three hundred and fifty-two enterobacterial isolates were successfully identified by biochemical testing (commercial ENTEROtest 24) and selected isolates confirmed by molecular techniques (PCR, 16S rDNA sequence analysis). A total of 39 enterobacterial species were isolated from cave waters, with predominance of Escherichia coli, Serratia spp. and Enterobacter spp. PCR amplification of lacZ gene is not specific enough to provide a reliable detection of coliform bacteria isolated from the environment. Sequence analysis of 16S rDNA confirmed that all of the selected isolates belong to the family Enterobacteriaceae. In general, physical and chemical parameters of cave waters in Slovak Karst corresponded to national drinking water quality standards