The biogeochemical role of Actinobacteria in Altamira Cave, Spain

A previously unrecognized species of Actinobacteria plays a significant biogeochemical role in the formation of grey spots on the walls and ceiling of Altamira Cave, Spain. These spots, composed of bacteria and bioinduced CaCO3 crystals, exhibit a distinct radial and dendritic structure. Molecular analysis identified Actinobacteria as the primary component, while CO2 efflux measurements confirmed that these microorganisms promote CO2 uptake from the cave atmosphere, dissolving the rock and generating CaCO3 crystals during periods of lower humidity or CO2 levels. The study combines electron microscopy techniques with geochemical data to propose a model for spot formation, shedding light on microbial contributions to cave mineralization processes.

Cuezva, S., Fernandez-Cortes, A., Porca, E., Pašić, L., Jurado, V., Hernandez-Marine, M., Serrano-Ortiz, P., Hermosin, B., Cañaveras, J. C., Sanchez-Moral, S., & Saiz-Jimenez, C. (2012). The biogeochemical role of Actinobacteria in Altamira Cave, Spain. FEMS Microbiology Ecology, 81(1), 281–290. https://doi.org/10.1111/j.1574-6941.2012.01391.x