Ancient microbes appear to have used molybdenum as far back as 3.7 billion years ago, despite the metal being scarce in Earth’s early oceans.

Scientists funded by NASA have found that organisms living on Earth more than 3 billion years ago were already using molybdenum, even though the metal was extremely rare in the environment at that time. The research, in Nature Communications, is the first study to show that ancient life depended on molybdenum this early in Earth’s history.

Today, molybdenum plays a key role inside cells by helping important biochemical reactions happen faster. It forms part of essential enzymes that drive several major biological processes in living organisms. These reactions matter not only for individual forms of life, but also for planet-scale biogeochemical cycles, including the nitrogen cycle. Without molybdenum, the same reactions could still occur naturally, but far too slowly to support life.