Researchers Have Uncovered a Missing Piece in Life’s Origin Story

Deep beneath the ocean, mineral-rich hydrothermal vents may have held a key chemical reaction. This reaction could have helped start life on Earth.

Researchers at the University of Alberta believe they found a missing piece in the puzzle of how life began.

How Life Might Have Started

Many scientists think life began on the ocean floor. This was near hydrothermal vents that release heat and minerals from under the Earth's crust. These vents could have provided energy and materials for early chemistry. But a big question remained: how did essential nutrients, like carbon and nitrogen, become available without sunlight? These nutrients were needed in large enough amounts to support the first living things.

To find answers, Long Li and his team looked at rock cores. These cores were drilled about 200 meters into the oceanic crust in the South China Sea. They found signs of something called abiotic nitrogen reduction (ANR). In this process, minerals act like catalysts, changing nitrogen into forms that life can use. The team thinks this reaction likely created the nutrients needed for life to appear.

One important result of this process is ammonium. Li explained that ammonium is crucial for making organic compounds. These compounds are the basic building blocks for the earliest forms of life.

The study was done with researchers from the South China Institute of Oceanography. It was published in Nature Communications.

Evidence from the Ocean Floor

Li said this discovery "fills in the gap for the first-step reaction in the origin of life." He added that people have looked for this reaction for a long time. This is the first time there is strong proof it happens on Earth, and likely happened on early Earth too.

Scientists have created ANR in labs. But finding it in natural ocean settings has been hard.

The authors noted that modern biological activity changes nitrogen in seawater and sediments. This makes it tough to tell natural signals from those made by living things. By studying deeply buried rock samples, the team found chemical evidence that matched a non-biological nitrogen reduction process.

Solving the Faint Young Sun Paradox

These findings might also help explain the "faint young sun paradox." This puzzle asks how liquid water could have been on early Earth when the young Sun gave off less energy. Climate models suggest surface temperatures should have been well below freezing.

However, geological records show liquid water was present at least 4.4 billion years ago. Li believes this contradiction can be explained by greenhouse gases like carbon dioxide, methane, and ammonia. These gases would have trapped heat in the atmosphere. Hydrothermal vents on the seafloor might have helped create these gases. This would have contributed to a warmer climate and the chemistry needed for life.

Li also said the strong evidence from the South China Sea suggests this reaction was not just in one place.

"We definitely need more evidence to show that," he said. "But since the conditions for ANR are common in both modern and ancient oceans, we reasonably speculate that this could happen globally over Earth’s history.”

Deep Dive & References

Abiotic N2 reduction in submarine hydrothermal systems could quickly fertilize prebiotic oceans - Nature Communications, 2025