Researchers have discovered bundles of “dark oxygen” forming on the ocean floor.
In a new study, over a dozen scientists from Europe and the United States examined “polymetallic nodules,” chunks of metal that cover large areas of the sea floor. These nodules, along with other items found on the ocean floor in the deep sea between Hawaii and Mexico, were subjected to various experiments, including injections with other chemicals or cold seawater.
The experiments revealed that the nodules were creating more oxygen than they were consuming. Scientists have termed this output “dark oxygen.”
Approximately half of the world’s oxygen comes from the ocean, previously believed to be entirely produced by marine plants through photosynthesis. Similar to land plants, these marine plants use sunlight to absorb carbon dioxide and produce oxygen. However, in this study, scientists examined nodules located about three miles underwater, where sunlight cannot penetrate.
This isn’t the first time nodules have drawn attention. Made of minerals like cobalt, nickel, manganese, and copper, these metal chunks are essential for making batteries. These materials may be responsible for the production of dark oxygen.
“If you put a battery into seawater, it starts fizzing,” lead researcher Andrew Sweetman, a professor from the Scottish Association for Marine Science, told CBS News partner BBC News. “That’s because the electric current is actually splitting seawater into oxygen and hydrogen [which are the bubbles]. We think that’s happening with these nodules in their natural state.”
The metals on these nodules are valued in the trillions of dollars, sparking a race to extract them from the ocean’s depths through a process known as deep-sea or seabed mining. Environmental activists have condemned this practice.
Sweetman and other marine scientists are concerned that deep-sea mining could disrupt the production of dark oxygen and threaten marine life that may depend on it.
“I don’t see this study as something that will put an end to mining,” Sweetman told the BBC. “[But] we need to explore it in greater detail and we need to use this information and the data we gather in future if we are going to go into the deep ocean and mine it in the most environmentally friendly way possible.”
