Scientists have uncovered a surprising process occurring deep within Earth’s oceans. Metallic minerals at the bottom of the sea are triggering chemical reactions that produce an enigmatic substance known as “dark oxygen,” leaving researchers both puzzled and fascinated.
Unseen Oxygen Makers of the Deep Sea”
In the ocean’s darkest depths, far from the sun’s reach, curious metallic clusters scattered on the seabed have stunned researchers with their ability to produce a unique type of oxygen, aptly named “dark oxygen.” Thought to be unavailable at such black abyssal reaches, this discovery contrasts with our prior understanding that half of our planet’s oxygen originated from sunlight-fueled photosynthesis by ocean plants.
These metal-rich “nodules” deep on the ocean floor, some five kilometers below, have been found to engage in a perplexing reaction, chemically cleaving the elements of seawater into separate entities of hydrogen and oxygen.
This process has now come under threat; numerous mining operations eye these valuable seabed nodules with intent to harvest. Marine scientists are raising the alarm that such activities could put an end to this intricate production of oxygen, endangering deep-sea life reliant on this cryptic ecosystem service.
Seafloor Oxygen Challenges Old Beliefs
In 2013, Professor Andrew Sweetman from the Scottish Association for Marine Science made an accidental but potentially ground-breaking discovery. Deep in the ocean’s abyss, where sunlight fails to penetrate, he observed a significant production of oxygen on the seafloor. Initially, Sweetman disregarded this phenomenon, conditioned to believe oxygen could only be produced through photosynthesis. Over time, however, the realization dawned on him that he might have overlooked an important scientific finding that challenged traditional understandings of oxygen production.
Sweetman and his team’s research took place in the deep expanse of ocean lying between Hawaii and Mexico, a region blanketed with metallic nodules. These nodules, resulting from the accumulation of dissolved metals on shell fragments or similar debris, evolve over millions of years. Rich in valuable metals such as lithium, cobalt, and copper—essential for battery production—these nodules have attracted the attention of mining companies looking to tap into these underwater treasures.
However, besides their economic value, Sweetman uncovered that these nodules play a crucial role in generating “dark oxygen,” a process that could support unknown ecosystems residing on the ocean floor. Published in the journal Nature Geoscience, his findings introduce fresh concerns about the environmental impact of deep-sea mining, highlighting a delicate balance between technological advancement and the preservation of unseen marine life.
Metal Nodules as Underwater Oxygen Sources”
Professor Andrew Sweetman and his team have unveiled a fascinating discovery beneath the waves, where metal nodules on the seafloor mimic batteries, churning out oxygen without sunlight or biological interventions. By catalyzing a reaction with seawater similar to how batteries release gas when submerged, these nodules might be splitting water into oxygen and hydrogen, akin to natural electrolysis. Lab tests reinforce this theory, showing nodules can generate significant electrical currents, hinting at a potential for these processes on distant moons and planets too.
This insight, however, is shadowed by the environmental threats posed by the looming industry of seabed mining, particularly in the biodiverse Clarion-Clipperton Zone. The extraction could devastate the deep-sea life and habitats that we’re only beginning to understand. Over 800 marine scientists worldwide urge for a halt in mining operations to protect these mysterious ecosystems, suggesting that besides their mineral wealth, the nodules are invaluable for the oxygen they supply to deep ocean life. While not a call to cease mining entirely, Sweetman emphasizes the necessity of informed, eco-conscious exploration of these underwater treasures.
