Dark Oxygen Discovered in the Ocean: What Does It Mean?

Plants, whether in the ocean or on land, largely produce the oxygen essential for intelligent life as we know it through photosynthesis of carbon dioxide. However, new research suggests that depths with no light might generate oxygen without relying on living organisms.

The authors of the study, published in Nature Geoscience, collected samples of marine sediments to measure oxygen consumption at the ocean floor. They expected reactions with sediments and organisms to decrease oxygen levels, but they discovered something surprising: in some experiments, oxygen levels actually increased, prompting questions about how this oxygen was being produced.

The researchers found that this “dark” oxygen production only occurred in the presence of polymetallic nodules and metal-rich sediments, known as metalliferous deposits. They believe these nodules contain the necessary combination of metals and are dense enough to conduct an electrical current, allowing electrolysis to split hydrogen and oxygen from water molecules (H₂O).

The team also suggests that the amount of oxygen generated may vary depending on the concentration and composition of nodules on the ocean floor. This study is part of an investigation into the impact of mining metals like lithium, cobalt, and copper—resources used in rechargeable batteries and electrical wiring—in pursuit of sustainable benefits for humanity and the planet.

The research focuses on the Clarion-Clipperton Zone in the Pacific Ocean, where vast reserves of these metals lie between Hawaii and Mexico. However, scientists warn that large-scale mining in this area may cause irreversible damage to marine ecosystems, and many countries are calling for a moratorium to protect these fragile habitats.

Dark Oxygen and Life

This discovery may have implications for life elsewhere. Oxygen is crucial for complex life, and photosynthesis, which generates oxygen as a byproduct, is what enabled the biodiversity we know. However, the finding that metal-rich nodules can generate oxygen suggests an additional oxygen source for the biosphere.

To fully understand the impact of these nodules on evolution, we still need to investigate more about the origins and formation of these deposits. Research like this highlights just how much we still don’t know about the origins of life on Earth.

Read the original article on: Science Alert

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