The discovery is groundbreaking: Previously unknown viruses live in the subsurface of our planet; they infect unicellular microorganisms, the so-called Altiarchaea. The remarkable thing: They start the food chain in an ecosystem that is actually hidden from our eyes. An international team led by Professor Dr. Alexander J. Probst from the University of Duisburg-Essen (UDE) made the respective discovery. The results were published in the scientific journal „Nature Communications“ *.