Discovery of “Dark Oxygen” Produced at the Sea Floor Where No Light Can Reach! GEO GIRL

A recent (2024) study has found molecular oxygen (O2) being produced at the seafloor! They are calling it 'dark' oxygen because, up to this point, we understood oxygen to form only by photosynthesis (aka: at Earth's surface, where light can reach). However, this dark oxygen was produced ~4000 m below the surface, where no light can reach! This discovery reshapes our fundamental understanding of how oxygen and carbon are cycled through Earth's systems. No longer is O2 production bound to Earth's surface. This has major implications for how we view Earth's chemical cycles and biosphere moving forward. In this video, I talk about the discover of dark O2 and the potential significances of this! Hope you enjoy ;D

0:00 Evolution of Oxygen on Earth
1:48 The Oxygen Cycle (as we knew it…)
3:20 Why O2 ‘shouldn’t’ be produced on the seafloor
4:10 Discovery of ‘Dark’ Oxygen
4:49 Where Dark O2 has been detected
5:16 How Dark Oxygen Forms
7:46 Significance of Dark Oxygen
10:06 Significance for the Origin of Life
12:39 Significance for Mining

References:

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[GEOGIRL]

UPDATE: Hi all, I want to thank you for all the engagement in the comments, it has been incredible to see so many ideas and questions inspired by this video! It has inspired me to make a follow up video answering the questions of "how these nodules form, how they are continually 'recharged', how much oxygen they produce relative to surface processes, and why they likely weren't abundant before the GOE".

There are a few ways they can form, but I need to look into what types of nodules this study focused on because of the multiple types (e.g., hydrogenetic, diagenetic, hydrothermal, etc.), and there are also different estimates in regards to their relative contirbution to total marine oxygen and if that oxygen even reaches the atmosphere or if it all gets consumed at depth. They have also drastically changed in abundance over geologic time, and were likely at low abundance on the seafloor before the GOE (great oxidation event, when oxygen first rose to appreciable levels in the oceans/atmosphere) because (1) oxygen in the atmosphere was necessary to induce enough continental weathering to transport the metals and ions to the ocean that eventually formed these nodules and (2) oxygen, or at least oxidized reactants, are necessary for these nodules to form in the first place because they are oxide minerals. In fact we use Mn oxide nodules as a proxy for oxic conditions (aquatic environments contianing dissolved O2), and thus, they likely didn't actually begin producing oxygen until post-GOE (aka: post-photosynthesis evolution/proliferation)- at least this is my understanding currently. I am going to look into all of this and make a much more comprehensive video trying to answer all these questions for you guys! And I will try to have it out by next week :) Thanks again for your support and patience!

[jonofthehill]

With all the A.I. content it is hard to find good new science channels on. Keep up the good work.

[tonydagostino]

I participated in Leg 86 of the Deep Sea Drilling Project in the far northwest Pacific. We found what we called "manganese nodules" in the core catchers of the first core barrel of every hole we drilled. Who knew? Some of these deposits form extensive blankets, possibly acres, of nodules in contact with each other. Good point about anaerobic early life but perhaps the earliest oxygen-users evolved in some of these chemical enriched O2-rich zones, next door to their anaerobic ancestors, and then they migrated to shallower environments.

[rassicr]

Don't tell your astronomer friends. Now if we find an extrasolar planet with oxygen we can't definitively say there's life because rocks are just too cool.

[frankheilingbrunner]

My question is: What keeps the process going? It's easy enough to create a chemical battery. The first "voltaic piles" were literally piles of metal disks interleaved with paper soaked in sulfuric acid. The battery produces voltage until it has consumed the chemical energy inside it, and then it stops. The fact that the nodules are still electrolyzing water after all this time indicates that either (a) something is applying voltage to the nodules to recharge them, or (b) metals are accreting onto the nodules fast enough to maintain the supply of electrochemical energy.

[jourdansarpy]

The more we learn about geobatteries, the more we learn that we definitely should NOT be mining the sea floor.

[wadeodonoghue]

These rocks may be our planet's defibrillator.

[Siletzia]

Geo Girl is one of my all-time favorite YouTube hosts. Always interesting and informative, and I always learn something new!

[rebdomine]

We are only just beginning to learn about this biome, it would be a shame to lose it for the sake of making some cars. Thank you for being upfront and saying it will likely be mined, you are just being realistic about the situation and I like to see it

[tomasjefferson]

Just found this channel because of this video and I already love the way you do the little presentation about the topic. Feels like I’m getting taught by a young teacher lol. Will definitely watch more!

[wasbedeutet]

I love that you record with zoom! It's like a recorded conference presentation!

[sparklytreesarecool]

Thank you, Dr. Rachel!! You are a great teacher.

[lethargogpeterson]

I'd be interested to know (only after a lot more research, I assume) how much of Earth's oxygen is made this way, like what proportion of yearly oxygen production this contributes. Great topic and video.

[Bushidounohana]

Very cool! So grateful to have stumbled upon your content—a glistening example of why social media ain’t all bad. Instant sub—thank you for your work!

[sethorlando]

Thank you Geo Girl for the informative video!

[terenceokane]

This is so cool! I've been hearing about it all week. Science never stops surprising us!

[matsciguy-lh]

Extremely interesting, it adds another consideration for OoL researchers. I'll be looking forward to any updated content you might create.

[alphacentauri]

Wonderful. I got exhausted by the brilliant integrated graphics. WTF. You are not being paid enough for that quality !? Your personal presentation is even better. Can't see how something so recent could have been part of your PhD work. ?. I loved it all. Thank you for all the 'you do give a damn' material.😶

[The_Tauri]

Yes! Been waiting for this explainer ever since the news dropped! Thanks for the clear explanation.

[nigtendos]

You're totally going to blow up as a channel and I'm all there for it :) nice vid