Microbe-Mineral Interactions in Caves

Microorganisms are crucial catalysts for elemental cycling in most of Earth's environments, and caves are no exception.Because photosynthesis is limited to the entrance and twilight zones, cave ecosystems either depend on allochthonous inputs of surface organics, or primary production by chemosynthetic microorganisms that can take advantage of in situ mineral resources or other energy-rich inorganic compounds.These microorganisms are geological agents that can contribute to cave formation by producing acids and corroding bedrock.In other cases, microorganisms form secondary mineral deposits by catalyzing metal oxidation, creating sulfate precipitates, and inducing carbonate precipitation.Further complicating analysis, mineral precipitation can also be nucleated passively on microbial communities, even sometimes forming on dead organisms.In this presentation, we will review energy resources for cave life, highlight the diversity of microbial habitats within caves, and describe case studies in which microorganisms play direct roles in limestone corrosion and speleothem formation in order to provide context for the microbial interactions with sulfur, iron, and manganese minerals that occur in Fort Stanton Cave.Caves are windows through which we can study the ubiquitous and globally distributed subterranean microbiota that not only play an active role in the evolution of karst, but in subsurface environments across the globe.