Oxygen: You love it. It's great. You love to breathe it.
You may have thought that oxygen was the only breathable O2 there was. But it turns out there's another, uh, darker form of the stuff out there!
Most oxygen on Earth is produced by photosynthesis, as plants and plankton gobble sunlight for food and produce that oh-so-wonderful, life-giving O2. However, that's not the only way oxygen can be produced. Enter "dark oxygen," a process that isn't as nefarious as it sounds. Simply put, it refers to oxygen produced without sunlight.
There is apparently some dispute about whether or not this stuff exists, or to what extent. Scientists in 2024 argued that "polymetallic nodules" at the bottom of the ocean were generating oxygen. The jargon-heavy explanation goes:
As millions of years of metallic layers built up in the nodules — similar to a voltaic pile — the differing electric potential could theoretically produce enough energy to split water into oxygen and hydrogen.
Millions of years, huh?
Biogeochemist Andrew Sweetman stood by that hypothesis last year even amid major criticism of his findings. And now he's headed back to the briny deep to try and prove his critics wrong:
According to New Scientist, the team will use custom-built landers that can descend up to 12,000 meters below sea level, which is twice the required depth needed to study the nodules. The researchers will also search for the presence of hydrogen, which was not specifically tested in previous research, to further confirm that electrolysis is taking place.
As the BBC notes, the confirmation of dark oxygen at the ocean's depths could point the way toward more significant discoveries elsewhere: "If oxygen - a vital component of life - is made in the dark by metal lumps, the researchers believe that process could be happening on other planets, creating oxygen-rich environments where life could thrive."
Be quite a laugh if we discovered proof of life on Neptune at the bottom of the Pacific!
P.S. Now check out our latest video 👇
