00:00When we venture into the glacial depths of the Pacific at 4,000 meters below the surface, a strange phenomenon occurs.
00:08Oxygen levels rise abruptly.
00:10This makes no sense because we are then plunged into a terrifying darkness.
00:15It was then that the researchers realized that they were confronted with a totally unprecedented discovery, dark oxygen.
00:22This particular type of oxygen, which forms in the cold abysses of the ocean,
00:27could shake our understanding of the origins of life on Earth.
00:30It could even bring us closer to the possibility of discovering life on distant planets.
00:35And this discovery was made by sheer chance.
00:38Our exploration begins in the Clarion-Clipperton area,
00:42a vast region of the Pacific that extends over a surface larger than that of Mexico.
00:46Reaching the depths of this place, we come across strange piles of the size of potatoes, scattered on the seabed.
00:54These formations are officially designated as polymetallic nodules.
00:58Although they may seem insignificant at first glance, these small structures actually contain hidden treasures.
01:06Over millions of years, metals dissolved in seawater slowly accumulate around tiny fragments of shells or debris,
01:13giving birth to these nodules.
01:14Inside, we find precious metals such as manganese, nickel, copper and cobalt,
01:21essential for the manufacture of the batteries of our mobile phones and electric vehicles.
01:26This is why the Clipperton fracture zone has become a high point of underwater mining.
01:32To date, 16 companies specializing in the exploitation of large funds
01:36have obtained permission to explore about 20% of its underwater surface.
01:41This rumble towards the depths aroused the curiosity of the researchers,
01:45eager to unravel the mysteries of the abyss.
01:48They therefore deployed the means to collect samples of sediment.
01:52And it was at this moment that things took a strange turn.
01:55The instruments began to reveal something unimaginable.
01:58Significant amounts of oxygen produced on the seabed, in total and absolute darkness.
02:04Wait a minute, this shouldn't happen.
02:08The more we go down into the ocean, the less oxygen we find in the water.
02:11At about 900 meters deep, there is almost no oxygen left,
02:15because the water is too far from the surface to allow any exchange with the atmosphere.
02:19To complicate things, oxygen is continuously consumed by living organisms in the deep,
02:25as well as by bacteria that decompose organic matter.
02:28Thus, the production of oxygen at this depth is supposed to be impossible.
02:33At first, the researchers did not believe it.
02:36They assumed that the sensors were defective.
02:39Because all the studies carried out in the marine depths
02:42had shown that oxygen consumption was never its production.
02:46However, the same results kept coming back.
02:49For 10 years, this mysterious oxygen continued to appear.
02:53They eventually came to the conclusion that their data could be correct.
02:58It turns out that these metallic nodules could actually generate oxygen by acting like batteries.
03:03When you immerse a battery in seawater,
03:06you can observe bubbles and hear a crackling,
03:09because the electric current decomposes seawater into oxygen and hydrogen,
03:13in a process called electrolysis.
03:16Thus, the theory advanced by the researchers suggested that these nodules
03:20performed the same function, but in the natural state.
03:23And they were right.
03:25The nodules were indeed charged electrically,
03:28with a voltage of about 0.95 volts.
03:31This level of energy is insufficient to dissociate seawater into hydrogen and oxygen.
03:36It would take about 1.5 volts,
03:39or the power of a AA battery.
03:41However, when these nodules regroup,
03:44much higher tensions can be observed,
03:47enough to trigger the reaction and produce oxygen.
03:50Thus, these nodules were able to generate electric currents
03:55powerful enough to decompose seawater molecules
03:58and produce oxygen,
04:00even in the total absence of light.
04:02This discovery is fascinating,
04:04because it questions our understanding of the production of oxygen.
04:08Until now, we had always believed that oxygen was generated by photosynthesis,
04:13this process by which plants and algae transform sunlight into energy
04:18and release oxygen.
04:20But in this totally dark marine environment,
04:23oxygen was produced only by electrolysis.
04:26No sunlight was necessary.
04:28This is why we began to call it dark oxygen.
04:32This discovery encourages us to reconsider how life could have emerged on Earth
04:37more than 3 billion years ago.
04:39Think about it.
04:40Plants need oxygen to live,
04:43but they are also the producers of it.
04:45So where did the first oxygen come from?
04:49This complex dilemma is like the puzzle of the hen and the egg.
04:53But it could be that there is now an answer,
04:56knowing that oxygen can be produced without using sunlight or photosynthesis.
05:02It is conceivable that a mysterious source of oxygen existed at that time,
05:06thus allowing breathing life forms to evolve
05:10even before photosynthesis was established.
05:13Dark oxygen does not only modify our understanding of the terrestrial past,
05:17but it also opens up new perspectives on life elsewhere in the universe.
05:22If this phenomenon occurs on our planet,
05:24it is plausible that it also occurs on other celestial bodies.
05:28Let's take as an example the moon Enceladus of Saturn
05:31and the moon Europe of Jupiter.
05:34Both seem to shelter liquid and saline oceans,
05:37concealed under thick layers of ice.
05:40Could dark oxygen also generate environments rich in oxygen in these oceans?
05:45The repercussions of this discovery go far beyond our solar system.
05:50It pushes us to reconsider the way we define habitats suitable for life.
05:55In our explorations of exoplanets orbiting distant stars,
05:59understanding the production of oxygen in the dark
06:02could help us locate places where life could exist
06:05in very different conditions from those on Earth.
06:08Instead of limiting ourselves to the search for planets bathed in sunlight,
06:12scientists could have to explore signs of chemical reactions
06:16likely to promote life even in total darkness.
06:20These news are exciting,
06:22but let's not forget the starting point of our story.
06:25High-sea mining.
06:28This is how this process usually takes place.
06:31Companies deploy a remote-controlled submarine vehicle,
06:35similar to a tractor, to move along the ocean floor.
06:39This vehicle collects the metallic nodules and sediments,
06:43then sucks them through a pipe to a surface vessel.
06:47Once the nodules are collected,
06:49the crew sends the residual sediment into the ocean at an intermediate depth,
06:53where it ends up being deposited again on the seabed.
06:56So, is mining in deep water beneficial or harmful?
07:01It's hard to tell.
07:03On the one hand, we have discovered a massive and promising metal deposit
07:07essential to the manufacture of new ecological technologies
07:11such as solar panels and electric vehicles.
07:14With a demand for these critical materials,
07:16which could rise to 600% in the next decades,
07:20mining in the high seas could prove to be decisive.
07:24Some research even suggests that this activity could be less harmful
07:29than conventional mining.
07:31As it takes place far from the coast,
07:34it could help preserve forests and avoid pollution from fresh water sources.
07:39In addition, the fact that these minerals are difficult to access
07:42could facilitate the monitoring of this activity,
07:45thus allowing to maintain control and regulate the process.
07:49However, there is also a growing concern
07:52that the search for precious minerals in the ocean
07:56could disrupt the production process of this dark oxygen.
07:59These metal-rich nodules are not just inactive,
08:03they play a role in the chemical processes that influence our planet.
08:07Indeed, they could be essential to many things,
08:10from nutrient cycles to the emergence of new forms of life.
08:13Scientists therefore fear that mining
08:16will damage marine life and habitats that depend on dark oxygen.
08:21Despite its isolated location and its extreme conditions,
08:24the Clareon-Clipperton area houses an amazingly varied and mysterious range
08:29of large-bottom creatures,
08:31ranging from sea anemones to spectral whites,
08:33and sea cucumbers from a deep violet to small marine isopods,
08:37cousins far from the Cloportes.
08:40However, our knowledge of these inhabitants of the depths remains limited.
08:44It is estimated that 90% of the species living in the deep waters of this area
08:49are still unknown to science.
08:51We know that they exist, but they have not yet received official names,
08:55and their classification remains impossible.
08:58Like these strange creatures, evolving in total darkness,
09:02remaining largely unknown,
09:04it is difficult to determine whether they or their habitats would really be threatened
09:08if mining in the high seas continued without a break.
09:12What specialists find is the need to study more,
09:17to collect more data, and to acquire a deeper understanding.
Comments