Note: Single-source report; awaiting corroboration.
NASA-funded researchers have discovered that life on Earth more than 3 billion years ago depended on the metal molybdenum, which was extremely rare in the environment at that time. As reported in Nature Communications, this is the first finding to demonstrate molybdenum use by such ancient life forms. Today, molybdenum is vital for key biochemical processes, serving as a component of enzymes fundamental to major biological reactions. These enzymes are essential for both individual organisms and global biogeochemical cycles, including the nitrogen cycle. Without molybdenum, these reactions would proceed too slowly to sustain life.
Betül Kaçar, head of the Kaçar Lab and senior author of the study, highlighted molybdenum's catalytic role in enzymes that oversee essential carbon, nitrogen, and sulfur reactions. Identifying when life began utilizing molybdenum helps pinpoint the emergence of critical metabolic strategies.
Although molybdenum is relatively abundant today, geological data show that Earth's ancient oceans contained only trace amounts billions of years ago. Molybdenum levels rose around the time microorganisms adopted photosynthesis, leading up to the Great Oxidation Event about 2.45 billion years ago, which significantly shaped life’s evolution. Prior NASA research suggested that this rise in molybdenum may have been necessary for complex life to develop.
Scientists previously speculated that early life might have relied on other metals like tungsten, which behaves similarly in cells and is used by some modern organisms in extreme environments. The new research analyzed molybdenum prevalence over time and traced its use across the tree of life, finding that, despite its scarcity, ancient microbes still utilized molybdenum. The study also notes tungsten's usage but indicates molybdenum was employed early on.