Image: © Richard Carey/Stock.adobe.com
A new form of oxygen production has been detected on the ocean floor, raising concerns about the impact of deep-sea mining to this vital ecosystem.
Researchers have discovered large amounts of oxygen being produced deep in the Pacific Ocean – and the source appears to be lumps of metal.
The researchers made the discovery in a region of the ocean 4,000 metres down, where a large amount of “polymetallic nodules” cover the ocean floor. The scientists believe that these nodules are producing this “dark oxygen”.
The team said the discovery is fascinating, as it suggests there is another source of oxygen production other than photosynthesis. It is believed that these metal nodules are acting as “geo-batteries”.
These nodules are believed to play a role in the dark oxygen production (DOP) by catalysing the splitting of water molecules. The researchers say further investigation needs to be done after this discovery to see how this process could be impacted by deep-sea mining.
“Whereas this process requires further investigation, if true, DOP activity may fluctuate with sediment coverage on the nodules inviting the urgent question of how sediment remobilisation and distribution over large areas during deep-sea mining may influence DOP,” the researchers said in the study.
As part of the study, the researchers released a module that sinks to the sea floor to perform automated experiments. This module then confined a small area of the ocean floor to measure how the concentration of oxygen changed over a few days.
Rather than going down from organisms consuming oxygen, the experiments found that the level of oxygen went up in these experiments.
Study co-author Prof Andrew Sweetman said he initially attributed these results to a sensor malfunction, but noticed that the phenomenon kept occurring in subsequent experiments.
“I suddenly realised that for eight years I’d been ignoring this potentially amazing new process, 4,000 metres down on the ocean floor,” Sweetman said in a Nature article.
Sweetman said that researchers should map the areas where oxygen production is occurring before deep-sea mining occurs, due to the potential impact it could have on ecosystems.
“If there’s oxygen being produced in large amounts, it’s possibly going to be important for the animals that are living there,” he said.
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