An underground oasis for microbial life at the interface of Earth’s atmosphere and terrestrial subsurface

Karstic caves represent unique underground environments under constant stygian darkness and devoid of nutrients, while in constant interaction with Earth’s atmosphere. Moonmilk is a secondary cave formation made up of a tight mesh of calcium carbonate spicules in an aqueous medium resulting in a soft, ‘cream-cheese’-like texture. In this talk, I leverage metagenomics and correlative light and electron microscopy (CLEM) data generated from three caves in the German Swabian Alps to illuminate the ecology and encoded function of moonmilk microbiomes. Hundreds of metagenome-assembled genomes with numerous carbon fixation, sulfur and nitrogen cycling pathways were recovered that spanned multiple bacterial and archaeal phyla. Phenotypes of prokaryotes inhabiting this environment were observed via CLEM, paving the way to high-resolution, taxonomy-aware microscopic detection of symbioses, viral infections and syntrophies. Despite their remoteness and adverse conditions presented, microbial life in karstic caves has the potential to meaningfully affect global biogeochemical cycling.

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* To access the meeting in the app without using the link, use the meeting 386 785 174 409 281 and access code 6vG6Jh3C