A recent study has uncovered a surprising source of oxygen in the deep Atlantic Ocean, challenging long-held beliefs about how life thrives in the abyssal plains. The research, published in the journal Nature on July 22, 2026, found that oxygen in the deep Atlantic is not only supplied by sinking surface waters but also generated in situ by a previously unknown process.
Scientists from the Scottish Association for Marine Science (SAMS) discovered that metallic nodules on the ocean floor, rich in manganese and other metals, can produce oxygen through a process called seawater electrolysis. This occurs when the natural electric potential of these nodules splits water molecules, releasing oxygen. This phenomenon, dubbed "dark oxygen," was first observed in the Pacific Ocean in 2024, but this is the first time it has been confirmed in the Atlantic.
The study, led by Dr. Andrew Sweetman, involved deploying sensors and sediment samples at depths of over 4,000 meters in the Atlantic. The team measured oxygen levels that increased over time in sealed chambers, indicating a local source of oxygen production. This finding has significant implications for deep-sea ecosystems, which rely on oxygen for respiration and nutrient cycling.
The discovery also raises questions about the potential impact of deep-sea mining, which targets these metallic nodules. If these nodules are essential for oxygen production, their removal could disrupt the delicate balance of deep-sea life. The researchers emphasize the need for further study and careful consideration of mining regulations to protect these unique habitats.
