Originally, this tale showed up on WIRED Italia and has been transformed from Italian.
For over a decade, Andrew Sweetman and his team have been exploring the seabed and its ecosystems, particularly in the Clarion-Clipperton Zone of the Pacific Ocean, an area scattered with poly metallic nodules. These rocks, as huge as potatoes, contain valuable metals—lithium, copper, cobalt, manganese, and nickel—that are utilized in battery production. These nodules present a tantalizing opportunity for deep-sea mining enterprises, which are devising methods to bring them up to the surface.
The nodules might serve as a possible reservoir of battery components, but Sweetman speculates they might already be generating something quite different: oxygen. Customarily, this element is produced through photosynthesis by organisms, but at a depth of 4,000 meters below the ocean’s surface, light does not penetrate. As proposed by Sweetman and his colleagues from the Scottish Association for Marine Science in a recent publication, the nodules could be instigating a reaction that generates this “cryptic” oxygen from seawater.
In 2013, Sweetman first observed something peculiar. While measuring oxygen movement in confined zones within nodule-rich regions of the seabed with his team, they noticed an increase in oxygen flow at the seabed despite the absence of nearby photosynthesizing organisms, to the extent that they initially thought it was an instrumental oddity.
This same discovery was replicated in 2021, albeit using a different approach to measurement. The researchers were gauging alterations in oxygen concentrations inside a benthic chamber, a device that gathers sediment and seawater to create enclosed samples of the seabed environment. This device enabled them to scrutinize, among other things, how microorganisms within the sample environment were utilizing oxygen. The oxygen encapsulated in the chamber should have diminished over time as the organisms in the water and sediment consumed it, but contrarily, under the lightless conditions inhibiting photosynthetic reactions, oxygen levels within the benthic chamber rose.
The anomaly required further examination. Initially confirming the absence of any oxygen-producing microorganisms, the team then hypothesized the involvement of poly metallic nodules captured in the benthic chamber. Post numerous laboratory experiments, Sweetman mentioned that the nodules behave akin to a geological battery: they create a weak electric current (approximately 1 volt each) that disintegrates water molecules into their constituents, hydrogen and oxygen, through electrolysis.
Nevertheless, the process by which the nodules generate oxygen remains shrouded in mystery: The origin of the electric current, the continuity of the reaction, and most crucially, the sustainability of an ecosystem from this oxygen production remain unknown.
Another critical query arises: What if the electrolysis incited by the poly metallic nodules was the genesis of life on Earth? Sweetman heralds this as a captivating hypothesis warranting further exploration. It might even be plausible for this phenomenon to occur on other celestial bodies, birthing potential extraterrestrial life forms.
These ideas bolster the case that the deep seabed is a vulnerable habitat requiring safeguarding against industrial exploitation. (A petition already exists, endorsed by over 800 marine scientists across 44 nations, shedding light on the broader environmental perils of deep-sea mining and advocating a cessation of its expansion.)
Yet, with myriad unanswered questions, some skeptics are questioning the veracity of the findings. The most notable criticisms have emerged from the realm of seabed mining: Patrick Downes from the Metals Company, a deep-sea mining enterprise operating in the same waters investigated by Sweetman and partially funding Sweetman’s research, disputes the results, alleging oxygen contamination from external sources and suggesting their company will soon release a counter paper refuting Sweetman’s group’s thesis.
