In the deep-sea habitat of the Pacific Ocean, 4,000 metres below the surface, where sunlight never reaches, researchers have discovered an unexpected supply of oxygen. This phenomenon, which has been dubbed "dark oxygen," is the first time that oxygen creation of this kind has been seen in the absence of living things.
Traditionally, photosynthetic organisms-such as plants and algae-have been blamed for producing oxygen.
But according to research that was just published in Nature Geoscience, oxygen may also develop in total darkness. This finding, achieved by a group under the direction of Professor Andrew Sweetman from the Scottish Association for Marine Science (SAMS), has the potential to fundamentally alter our knowledge of how oxygen is produced and how life first began.
"For aerobic life to begin on the planet, there had to be oxygen, and our understanding has been that Earth's oxygen supply began with photosynthetic organisms. But we now know that there is oxygen produced in the deep sea, where there is no light. I think we therefore need to revisit questions like, Where could aerobic life have begun?" the professor said in a statement.
As per the statement, the discovery was made while sampling the seabed of the Clarion-Clipperton Zone to assess the possible impacts of deep-sea mining. This process would extract polymetallic nodules that contain metals such as manganese, nickel, and cobalt, which are required to produce lithium-ion batteries for electric vehicles and mobile phones.
In the experiments, Professor Sweetman and colleagues found nodules to be carrying a very high electric charge, which could lead to the splitting of seawater into hydrogen and oxygen in a process called seawater electrolysis. Only a voltage of 1.5 V is needed for seawater electrolysis to occur-the same voltage as a typical AA battery. The team analysed multiple nodules and recorded readings of up to 0.95 volts on the surfaces of some, meaning that significant voltages can occur when the nodules are clustered together.
Professor Sweetman now says that more investigation into 'dark oxygen' production is required during deep-sea mineral extraction baseline investigations as well as an assessment of how sediment smothering during mining may alter the process.
