A groundbreaking study reveals that approximately 3.4 billion years ago, during the Archean Era, ancient microbes were not only reliant on molybdenum—a rare metal at the time—but also explored the use of tungsten. This discovery has the potential to transform how astrobiologists search for extraterrestrial life.
Early Earth. Image credit: Peter Sawyer/Smithsonian Institution.
Geochemical evidence indicates that the concentration of molybdenum in early Earth’s anoxic oceans was extremely limited; however, modern organisms are largely dependent on this essential element.
Previous theories proposed that life initially utilized tungsten before transitioning to molybdenum as it became more abundant.
Professor Betül Kaçar from the University of Wisconsin-Madison and her research team aimed to test this hypothesis.
“The transition metal molybdenum presents a puzzling evolutionary narrative in relation to biological systems,” the researchers stated.
“Molybdenum plays a significant role in vital biogeochemical processes involving carbon, nitrogen, and sulfur, which previous studies suggest have deep-rooted evolutionary histories.”
In their research, the authors analyzed genome databases to pinpoint species with genes responsible for molybdenum transport, storage, and enzymatic functions.
They applied a technique known as phylogenetic matching to trace the evolutionary lineage of molybdenum- and tungsten-utilizing proteins within the current tree of life.
Moreover, they investigated the mechanisms of molybdenum movement and utilization within living cells, focusing on intracellular transport from uptake to catalysis.
Simultaneously, they explored the historical context of biological tungsten use for similar functions.
The researchers compiled existing data regarding molybdenum’s prevalence over time and found that, despite its scarcity, ancient microorganisms on Earth found ways to utilize it, dating back to between 3.3 and 3.7 billion years ago.
“Counterintuitively, geochemical records suggest that the abundance of molybdenum on early Earth was significantly lower billions of years ago, particularly prior to the emergence of oxygenic photosynthesis,” noted Dr. Aya Cross, a student at the University of Wisconsin-Madison.
“Yet, life persisted in evolving biochemical pathways that depended on molybdenum, despite its limited availability.”
“These processes have been passed down to modern organisms.”
“Understanding the elemental dependencies of early life could aid astrobiologists in identifying other planets capable of supporting life,” Professor Kaçar remarked.
“This study illustrates that a lack of an element in the environment doesn’t negate the potential for life to adapt and exploit it in innovative ways.”
“Life exhibits remarkable adaptability, and insights like these remind us that the quest for extraterrestrial life may necessitate considering possibilities previously unimagined.”
A research paper detailing these findings was published in the latest edition of Nature Communications.
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AS Cross et al. 2026. The biological utilization of molybdenum and tungsten dates back 3.4 billion years. Nat Commun 17, 3943; doi: 10.1038/s41467-026-72133-0
Source: www.sci.news
