Bacterial and abiogenic carbonates formed in caves–no vital effect on clumped isotope compositions

Speleothems (dominated by cave-hosted carbonate deposits) are valuable archives of paleoclimate conditions. As such, they potential targets clumped isotope analyses that may yield quantified data about past temperature variations. Clumped stalagmites, however, seldom provide useful values due to various fractionation processes. This study focuses on the determination microbially induced vital effect, i.e., processes related bacterial production. A cave site with biologically mediated amorphous calcium precitation was selected as a natural laboratory. Calcite deposits were farmed under UV lamp prevent activity, well control Microbiological and morphological investigations using scanning electron microscopy showed treatment effectively reduced number cells, production strongly influenced carbonate’s morphology. Stable oxygen calcite drip waters, measurements revealed that, although most studied carbonates formed close equilibrium, ? 47 varied widely from equilibrium fractionated data. Site-specific kinetic fractionations played dominant role in distribution values, whereas did not result detectable effect.