The ‘Dark Oxygen’ mission aims at other worlds

Scientists who recently discovered that iron lumps in the Black Sea produce oxygen have announced plans to study the Earth’s deep oceans to understand the surprising phenomenon.

Their mission “could change the way we look at the possibility of life on other planets,” the researchers said.

The first discovery puzzled marine scientists. Previously, it was accepted that oxygen can only be produced by plants in sunlight – in a process called photosynthesis.

If oxygen – a vital component of life – is processed by iron oxides in the dark, the researchers believe that the process could occur on other planets, which would create oxygen-rich environments where life could develop.

Lead researcher Professor Andrew Sweetman explained: “We are talking to experts at NASA who believe that dark oxygen could change our understanding of how life would survive on other planets without direct sunlight.

“We want to get out there and find out exactly what’s going on.”

The first discovery caused a global scientific row – it was Criticism of the findings From some scientists and deep sea drilling companies who plan to collect precious minerals from the sea.

At these extreme depths, in total darkness, if oxygen is produced, it questions what life can survive and thrive on the sea floor, and what impact mining operations have on marine life.

That means offshore mining companies and environmental groups — some of whose findings have offered evidence that seafloor mining plans should be halted — will be watching this new investigation closely.

The plan is to operate at a depth of more than 10 km (6.2 mi) below the sea floor using remotely operated underwater instruments.

“We have instruments that go into the deepest parts of the ocean,” explains Professor Sweetman. “We’re sure we’ll find it somewhere else, so we’ll start investigating the cause.”

Some of these experiments, in collaboration with scientists at NASA, will aim to find out whether a similar process could support microscopic life in the oceans of other planets and moons.

“If there is oxygen, there can be microbial life that takes advantage of that,” Professor Sweetman said.

The first, biologically puzzling findings were published last year In Journal of Nature Geoscience. After several expeditions to the deep sea area between Hawaii and Mexico, Professor Sweetman and his colleagues sent sensors to the sea floor – at a depth of 5 km (3.1 miles).

That area is part of a vast sea floor covered in naturally occurring iron boils, which occur when metals dissolved in seawater collect on fragments of shells — or other debris. It is a process that takes millions of years.

The team repeatedly deployed sensors that showed rising oxygen levels.

Professor Sweetman told BBC News at the time, “I ignored it, because I was taught that you only get oxygen through photosynthesis.”

Eventually, he and his colleagues stopped ignoring their readings and set out to understand what had happened. Experiments in their lab – where the team collected lumps submerged in seawater – led the scientists to the conclusion that the metal lumps could produce oxygen from the seawater. The nodules produced electrical currents that could split seawater molecules into hydrogen and oxygen.

Then came the response in the form of rebuttals – posted online – from scientists and seabed mining companies.

Among the critics, Michael Clarke from the Metals Company, a Canadian deep-sea mining company, told the BBC that the criticism focused on “a lack of scientific rigor in the design of the experiment and the collection of data”. Essentially, he and other critics argued that there was no oxygen production at all—only bubbles produced by the device during sample collection.

“We’ve ruled that out,” replied Professor Sweetman. “But these[new]tests provide the proof.”

This may sound like a fine, technical argument, but several billion-pound mining companies are already exploring the possibility of harvesting these metals from the seabed.

The natural reserves they are targeting contain metals that are essential for making batteries, and the demand for those metals is increasing rapidly as many economies move away from fossil fuels to, for example, electric vehicles.

The race to extract those resources has raised concerns among environmental groups and researchers. There are more than 900 marine scientists from 44 countries They signed a petition They emphasized the environmental concerns and called for a pause in mining operations.

Speaking at a press conference on Friday about his team’s latest research mission, Professor Sweetman said: “Before we do anything, we need to understand the[deep sea]ecosystem as much as possible.”

“I think the right decision is to stop before we decide that this is the right thing to do as a global community.”