Microbially-mediated carbonate dissolution and precipitation; towards a protocol for ex-situ, cave-analogue cultivation experiments

Subterranean calcite dissolution and precipitation are often considered as strictly geochemical processes. The active involvement of microbes in these processes is commonly underestimated the literature due to general oligotrophic conditions caves, except particular cave conditions, such sulfidic caves moonmilk deposits, where presence likely plays a key role mineral deposition. Here, we study possible from Postojna Cave, Slovenia, carbonate (litholysis) (lithogenesis). Microbes were sampled small pools below hydrologically diverse drip sites incubated on polished limestone tablets at 10 20°C for 2 14 weeks under cave-analogue conditions. then observed scanning electron microscope investigate microbe–rock interactions. Our experiments showed various microbial morphotypes, associated with extracellular polymeric substances, firmly attached surfaces. Unfortunately, our surface sterilization method using 96% 70% ethanol could not establish complete aseptic deep natural cracks experimental tablets. Nonetheless, results emulate interaction environmental rock. Conspicuous association microbes. Furthermore, show evidence entombment Si-rich precipitate during nutrient-depleted growth suggest that silica mobilization ambient may be widespread overlooked phenomenon. findings have important implications microbial-mediation precipitation, including preservation past climate proxy signals speleothems prehistoric art. Improvements methodology further work suggested enable more robust ex-situ cultivation future, facilitating better detailed research into this topic.