For decades, dark matter has intrigued scientists for its role in holding galaxies together, but now a new mystery has emerged from the depths of the ocean: "dark oxygen." Researchers have uncovered this enigmatic form of oxygen at the ocean’s floor, raising intriguing questions about the origins of life on Earth.
A groundbreaking study published in ‘Nature Geoscience’ reveals that oxygen is being emitted from mineral deposits found 4,000 meters (approximately 13,000 feet) beneath the Pacific Ocean’s Clarion-Clipperton Zone (CCZ)—a depth nearly half the height of Mount Everest.
The research, led by Andrew Sweetman, a professor at the Scottish Association for Marine Science (SAMS), suggests that this dark oxygen source might alter our understanding of Earth's oxygen cycle. Traditionally, scientists believed that the planet’s only oxygen came from photosynthesis performed by plants and algae.
What is Dark Oxygen?
In the CCZ, which covers 4.5 million square kilometers (1.7 million square miles), scientists have discovered that coal-like mineral rocks known as polymetallic nodules, rich in manganese and iron, release oxygen without the need for sunlight. This unexpected discovery challenges the prevailing view of how oxygen—and potentially life—originated on Earth.
“The revelation of an alternative oxygen source could indicate that aerobic life existed before the advent of photosynthesis,” Sweetman noted. “And if such processes occur here, they might also be happening on other planets.”
How Was Dark Oxygen Discovered?
This discovery builds on research that began over a decade ago. In 2013, scientists aimed to measure oxygen consumption by seafloor organisms. Submersible landers, which descended to the ocean floor, detected surprising results in oxygen levels. Sweetman’s team recalibrated their equipment multiple times and repeated experiments, eventually identifying manganese nodules as the oxygen source. Lab tests confirmed that these nodules can generate oxygen through a process similar to seawater electrolysis.
Why Does It Matter?
While the findings await further verification, the implications are profound. The discovery of another source of oxygen could reshape our understanding of Earth's early atmosphere and how life might have thrived before photosynthesis became prevalent. It also underscores the need to consider environmental impacts when contemplating deep-sea mining, which could affect these self-sustaining ecosystems.
“This new source of oxygen has significant implications for both our understanding of life’s origins and the protection of these deep-sea environments,” said Nick Owens, SAMS director.
“We must carefully weigh the effects of potential deep ocean mining on these crucial ecosystems.”
As scientists continue to unravel the mysteries of dark oxygen, this discovery opens new avenues for exploring the origins of life and the dynamic processes of our planet.
