Researchers have found potato-sized metallic nodules on the Pacific Ocean floor that create oxygen in total darkness. This process does not involve any living organisms.
The discovery of “dark oxygen” is the first time scientists have witnessed oxygen being produced without life forms. This finding challenges our current understanding of how life began on Earth, according to researchers.
Initial doubts about dark oxygen turned into a groundbreaking discovery
Andrew Sweetman, a professor at the Scottish Association for Marine Science, initially doubted the findings. “When we first got this data, we thought the sensors were faulty because every study ever done in the deep sea has only seen oxygen being consumed rather than produced,” he said.
However, when the instruments continued to show the same results, Sweetman and his team realized they had discovered something groundbreaking and previously unimaginable.
The study shows that small metallic nodules in the North Pacific’s Clarion-Clipperton Zone make oxygen through seawater electrolysis. This means seawater splits into oxygen and hydrogen when an electric charge is present.
This charge likely comes from differences in metal ions within the nodules, moving electrons around.
What are polymetallic nodules?
Polymetallic nodules are found on the ocean’s abyssal plains, which are flat areas of the seafloor. They are located between 10,000 and 20,000 feet (3,000 to 6,000 meters) below the surface. These nodules mainly contain oxides of iron and manganese.
They also have metals like cobalt, nickel, and lithium, along with rare earth elements such as cerium. These elements are important for making electronics and low-carbon technologies.
Sweetman and his team initially aimed to study how mining polymetallic nodules could affect the seafloor ecosystem in the Clarion-Clipperton Zone (CCZ). This vast abyssal plain covers 1.7 million square miles (4.5 million square kilometers) between Hawaii and Mexico.
As part of their research, they measured oxygen levels at various locations using special experimental chambers.
Unexpected oxygen emissions from the seabed challenge beliefs on life origins
Typically, oxygen levels decrease as you go deeper in the ocean because there is less light, leading to fewer photosynthetic organisms and lower oxygen production. However, instead of the expected decline, their data showed consistent oxygen emissions from the seabed.
The discovery of dark oxygen at 13,000 feet (4,000 meters) below the surface, where no light can reach, challenges the belief that Earth’s oxygen is only produced through photosynthesis.
In the dark depths of the ocean, untouched by sunlight, oxygen is being produced.
Photosynthesis is impossible in such darkness, scientists are working to find a source.
Findings suggest the electric charge from polymetalic nodules may separate hydrogen from oxygen in water.
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Usually, small amounts of oxygen are also produced by oxidizing ammonia, but these are quickly consumed. This finding raises new questions about the origins of life on Earth, which began around 3.7 billion years ago, said Sweetman.
The findings also bring up concerns about mining polymetallic nodules, which might be a crucial oxygen source for deep-sea ecosystems.
