He oxygen It is usually associated with life. In the popular imagination we usually conceive of it as an essential gas that living beings need to live. Also as a fundamental product in photosynthesis, but the idea of finding oxygen in abyssal waters, 4,000 meters deep.
Detect oxygen in a place without light seemed impossible, until May 2024, when a international team of ecologists reported the discovery of what is known as «dark oxygen«.
He discovery It occurred aboard the research vessel Nautilus, beneath the surface of the Pacific Ocean in the Clarion-Clipperton Zone (ZCC). It is an immense abyssal plain located between Hawaii and Mexico, rich in polymetallic nodules of nickel, copper, cobalt, manganese.
The region is administered by the International Seabed Authority (ISA) for its high biodiversitywith thousands of species discovered. At the same time, it is a key point of mining interestand the potential consequences of this discovery caused a stir when they were highlighted by the magazine Nature Geoscience.
A year and nine months passed since that report, and during all this time the same group of researchers prepared for a new odyssey towards the abyssal zone, with new instruments to determine the possible cause of the phenomenon.
Underwater robots to discover the source of «dark oxygen»
The prestigious academic dissemination magazine Naturereports that the team leader, Andrew Sweetmanfrom the Scottish Association of Marine Sciences (SAMS) in Oban, United Kingdom, held a press conference in London to anticipate what this odyssey in the depths will consist of.
The researchers presented a set of instruments designed specifically to analyze oxygen productioneither on the seabed or in laboratory experiments that reproduce deep sea conditions.
Organization and logistics involve high costs due to the inaccessibility of this territory. The Nippon Foundationa Tokyo-based charity, funded the follow-up studies with a grant from 5.2 million dollars.
In his speech at the event Sweetman described of probeseach with different capacities, designed to perch on the seabed, take measurements and samples.
«We will carry landers specifically designed to observe the production of dark oxygen«, he stated. The probes will have pH sensors to measure the concentration of protons in seawater.
The landers that made the original discovery could not measure pH because they were not designed to detect or study oxygen production.
These data are essential, since high levels of these protons would suggest that water molecules are breaking down and that molecular oxygen is forming in the abyssal zone.
The original study found dark oxygen in a region containing polymetallic nodules, ancient nuggets of valuable metals such as manganese and cobalt that form on the ocean floors over millions of years.
This led the team to speculate that these nodules, which look like large black trufflescould be catalysts for the breakdown of water, but this is not the only way oxygen could be produced deep below the surface.
The chemist Franz Geigerof Northwestern University in Evanston, Illinois, explained that he will conduct experiments in pressure chambers with polymetallic nodules recovered from the seafloor to investigate the electrochemistry of the rocks and examine their surfaces using special transmission electron microscopes that operate in liquid cells.
This tool will allow them to map the chemical states of metals on the surface in the presence of salt water.
The explanation of the controversy around «dark oxygen»
Sweetman’s team discovered oxygen while conducting studies to The Metals Company, a seabed mining company in Vancouver, Canada, to help measure how the mining of polymetallic nodules could affect the biological ecosystems in the abyss.
«It is important to understand the role of dark oxygen in marine ecosystems so that, If mining goes ahead, we can suggest mining practices that limit the damage as much as possible«Declared Sweetman.
The production of «dark oxygen» on the seafloor involves large amounts of gas, and what they need to know is what is generating oxygen, whether a natural chemical process capable of producing it, an unknown biological pathway, or even a mixture of both.
The objective of the mission became much more than evaluate environmental impacts linked to possible underwater mining.
The Clarion-Clipperton area is valued by companies, countries, organizations and scientists who must determine whether to extract these nodules and under what rules.
The new operation will be on the Nautilus research vessel to reach the study area in the Pacific and deploy landers, robotic platforms that descend to the bottom and act as stationary laboratories.
The critical phase will be when they return with the samples and contrast them with the results obtained in the mirror laboratory, a designed environment that will allow factors to be isolated and to verify whether the phenomenon appears with and without microbes, with different salinities and altered surfaces.
