The terrestrial subsurface houses about one third of Earth’s bacteria
and archaea, yet little is known about ecosystem structure and interaction
of microorganisms in the deep biosphere. In recent studies we
tackled this knowledge gap by using cold-water geysers as model systems
with high microbial activity. Scavenging biomolecules by symbiotic
Archaea and Bacteria functions as a carbon sink in these ecosystems
and creates complex nutrient networks that we are only at the
beginning of understanding.