# Have scientists got ocean carbon all wrong?

## Метаданные

- **Канал:** Just Have a Think
- **YouTube:** https://www.youtube.com/watch?v=4377fPKhdbM

## Содержание

### [0:00](https://www.youtube.com/watch?v=4377fPKhdbM) Segment 1 (00:00 - 05:00)

In November twenty-twenty-five a research paper was published in the online journal Nature focussing on the use of a naturally occurring radioactive atom, or radionuclide, called Thorium 234 as a high-resolution geochemical tracer to identify the extent of sediment plumes kicked up by machines during a deep sea polymetallic nodule mining test carried out by a company called Nauru Ocean Resources Inc. some four kilometres below the surface of international waters in the vast Clarion Clipperton Zone between Hawaii and the coast of Mexico. The paper’s authors explained that Thorium 234 can be USED as an indicator of plume extent because it occurs naturally on the ocean floor, it has a half-life of 24. 1 days, so it’s travel can be monitored very precisely, and it has a strong tendency to stick to particles in the environment — especially sediment and organic matter. The conclusion of the research was that although levels of Thorium 234 WERE elevated after mining, they declined to background levels after plumes reached one to two kilometres from the mining site, implying that potentially damaging effects of mining operations were very locally limited, and therefore not problematic in the way that some have suggested. Nauru Ocean Resources inc. is a wholly owned subsidiary of the Metals Company, which is arguably the most visible, best-capitalised, and most advanced commercial proponent of polymetallic nodule mining and certainly one of the industry’s most outspoken advocates. On the back of the Thorium 234 research findings, the Mining Company published its own interpretation which stated “The sheer scale of the ocean means sediment concentrations in commercial-scale midwater plumes dilute rapidly within a few kilometers. By coincidence, in December twenty-twenty-five a completely separate piece of research was published by a team at the University of California Santa Barbara showing how organisms on the deep ocean floor were capturing and storing carbon in ways that were previously not understood and which could have profound implications for the entire marine food chain and the capacity for our oceans to continue absorbing carbon dioxide from our atmosphere. So, I wondered if it might be worth having a think about how those two bits of research tally up. Hello and welcome to Just Have a Think If you’re a regular viewer of the channel you will know that I’ve made a couple of videos about Deep Sea Mining in previous years. The potted summary is this. Across the deep ocean floor, especially in the Pacific Ocean, there exist billions of nodules ranging from about the size of a golf ball to as large as a tennis ball. They are polymetallic. They typically contain cobalt, nickel, and manganese – all materials that now play a crucial role in our modern world. Developers like The Metals Company argue that sending machines down to the deep ocean seabed to scoop these nodules up would be far less environmentally damaging than the existing terrestrial mining operations that currently liberate these materials. Opponents point out that more than ninety-nine-point-nine-nine-percent of the biology of the deep ocean floor is as yet undiscovered and that far more research is required before deep sea mining should be allowed to go ahead. There was fierce debate on the subject at the most recent annual meeting of the International Seabed Authority, or ISA, which regulates what can be done in International Waters. Many countries — including France, Germany, Canada, Brazil, and others — have publicly supported a call for a moratorium or precautionary pause on deep-sea mining until sufficient scientific understanding and strong regulations are in place. To date, the ISA has not issued any licences to exploit deep sea polymetallic nodule fields while it continues to negotiate and finalise the legal and regulatory framework. I’ll come back to that debate a bit later on, but before we do that, let’s have a look at this December research paper from the team at the University of California Santa Barbara looking at the causes of dissolved inorganic carbon fixation, which arguably has one of the most unfortunate abbreviations in the scientific world. Anyway, the researchers appear to have found evidence that challenges existing thinking on HOW our oceans are able to store so much carbon dioxide – including, by the way, roughly a third of all the additional CO2 we humans have been spewing out into the atmosphere since the industrial revolution, which is a major reason why our global warming emergency isn’t even more catastrophic than we’re already witnessing. The existing scientific knowledge goes a bit like this – at the ocean’s surface, carbon dioxide gets pulled out of the atmosphere by tiny single-celled organisms like phytoplankton. They photosynthesize, just like plants on land, and convert INORGANIC CARBON into ORGANIC matter —essentially creating food for all the marine life higher up the chain. Below that sunlit layer, in what scientists call the dark ocean, the story has always been a bit less clear. After a few hundred metres there is no sunlight available, so there’s no photosynthesis. The accepted theory for carbon capture at those

### [5:00](https://www.youtube.com/watch?v=4377fPKhdbM&t=300s) Segment 2 (05:00 - 10:00)

depths has been that microbes called archaea, which get energy by oxidizing AMMONIA instead of photosynthesizing from sunlight, were the main drivers of inorganic carbon fixation down there. It’s a process the science bods refer to as chemoautotrophy. The trouble with that theory though, is that the numbers don’t stack up. Specifically, nitrogen availability doesn’t match up with expected rates of carbon fixation. And that requires a bit of explanation doesn’t it, so here’s my layman’s interpretation of the science. Very roughly speaking, while CARBON is a building material for stuff like sugars, fats and cell structures, NITROGEN is essential for proteins, enzymes and DNA. So, in biology, Carbon and Nitrogen cycles are tightly linked. In other words, if an organism is fixing a lot of carbon, then you would expect to see a corresponding uptake of nitrogen. And that is NOT what scientists see in deep ocean research. There’s just NOT ENOUGH nitrogen available to support the amount of carbon fixation being measured. So, the team at Santa Barbara, led by microbial oceanographer Alyson Santoro, set out to establish what was causing that discrepancy. And they used quite a clever method to do so. Instead of just observing carbon fixation rates, they went in and deliberately inhibited the ammonia oxidizers of the archaea without affecting other microbes. They achieved that with a chemical called phenylacetylene which selectively stops the enzyme that ammonia oxidizers use to kickstart their metabolism. The idea was that if the archaea WERE responsible for most of the dark ocean’s carbon fixation, then blowing up their metabolism should cause a big drop in carbon fixation rates. But when they ran the experiment, carbon fixation rates hardly dropped at all. What that suggested was that ammonia-oxidizing archaea may only be responsible for a small fraction of the total inorganic carbon fixed in the deep ocean —somewhere between four and twenty-five percent in the regions sampled. So, if ammonia oxidizers aren’t the main players, then what are? Well, the evidence from this research points to another family of microbes called heterotrophs. The weird part about that is that heterotrophs are normally considered to be CONSUMERS of ORGANIC carbon like the bits of decomposing plankton that I mentioned earlier. They were NOT thought to be significant FIXERS of INORGANIC carbon. And yet it now appears they’re incorporating dissolved inorganic carbon into their biomass to a much greater extent than anyone expected. That’s not to say they’re photosynthesizing that inorganic carbon in the way that surface plankton can. They don’t have any chlorophyll for start, and of course they can’t use sunlight, because there isn’t any down at those depths. They do have biochemical pathways though, 8:00 which allow small amounts of inorganic carbon to be incorporated into their cells during other metabolic processes. That WAS known about previously, but it was always thought to play only a very minor, and more or less insignificant role. Now, that established wisdom appears to have been turned on its head. Now, you might be thinking, so what? Who cares what’s doing the carbon capture four or more kilometres below the ocean surface, or how it’s being done? Which is a fair question. The answer, according to these folks, is that findings like these fundamentally change our understanding of the carbon BUDGET and tell us that the deep ocean ecosystems are even more complex than we already thought. The base of the food web — in other words what feeds everything else — might not just be sinking phytoplankton and deep-sea archaea. These heterotrophic microbes seem to be pulling more weight than expected. That reshapes the scientific view of energy flow and nutrient cycling in the deep sea, and it opens new questions about interactions between carbon and nitrogen cycles. Questions like How exactly are these heterotrophs fixing greater amounts of inorganic carbon, and what happens after that carbon is fixed. Do they release ORGANIC compounds that feed larger organisms in the marine food chain? And if so, how does that cascade up the food web? Does more carbon being fixed at depth mean more long-term storage of carbon? And would trampling over the deep-sea floor with industrial sized vacuum cleaners sucking up everything they run over have any material impact on the efficacy and productivity of a carbon fixation cycle that has likely existed down there for millions of years? I mean it’s just so hard to say, isn’t it? So, lets quickly pop back to our deep-sea mining debate then. A recent paper published in the Journal of Marine Science and Engineering provided independent experimental and Computational Fluid Dynamics modelling of deep-sea mining plumes showing that plume dispersion depends on current speed, particle size, discharge height, and other factors. The findings of this paper were that while INDIVIDUAL release events might be short and localised, SUSTAINED operations in multiple locations could produce persistent dispersion and deposits across broader areas

### [10:00](https://www.youtube.com/watch?v=4377fPKhdbM&t=600s) Segment 3 (10:00 - 13:00)

especially for fine particles. That modelling appears to be backed up by seabed disturbance tests from nearly three decades ago in deep sea regions that were recently revisited, showing long-lived microbial disruption even after twenty-six years. The authors of that research paper explain that “microbially mediated biogeochemical functions need over FIFTY years to return to undisturbed levels. ” That is not a quick bounce-back timeline. A separate 2025 Nature paper on mining tracks and recovery states explicitly that impacts extend beyond the immediate scrape zone: “Sediment plumes” say the authors “can redeposit beyond mined areas causing biogeochemical alterations of the sediment” So even if the deep-sea collection machine is “precise”, the ocean isn’t obliged to keep the mess neatly inside the lines. Another twenty-twenty-five INTEGRATED assessment summarises evidence from prototype trials showing that “collector plumes… can be passively transported hundreds of metres to several kilometres” The paper explains that this movement is highly consequential because microbial processes are spatially structured. In other words, what lives where, on what substrate and under which chemical conditions are all crucial factors that can make or break an ecosystem. Spread the plume, and you spread the disturbance footprint. Even the International Seabed Authority acknowledges that “deep-sea mining activities could, at a local scale, impair the carbon cycling ecosystem function by bacteria” “The restoration of these natural processes” says the ISA “is not fully understood. ” So, should we really be rushing down to the deep ocean floor to scoop up what could very well be a multi-billion-dollar bonanza for deep-sea mining companies? I know my view, and I suspect you’ve guessed what it is. But I’d be interested in your opinion as well. So as always, the place to leave your thoughts is in the comments section below. That’s it for this week though. We’re still marching towards 700,000 subscribers thanks to the thousands of you good folks who’ve been clicking that little button in recent weeks. I’ll be giving away ten of these hoodies when we reach that milestone. They’re not available for sale because I will never sell merchandise on this channel, but if you want a chance to win one, all you need to do is leave a suggestion for a video topic down there in the comments section. So, if you haven’t already subscribed and you feel I’ve earned it then that little click will really help us get to our target as quickly as possible so you can find out if you’re one of the lucky ten. You can also get early access to all my videos, cast your vote in monthly content polls and get direct access to me via chat forums by joining the amazing group of people over at Patreon dot com forward slash just have a think who directly support me in making my weekly videos without having to resort to ads and sponsorship messages. And I must just give a quick shout out to some folks who joined recently with pledges of ten dollars or more a month. They are Bea Rector, Penguin, Hugh Ayerst, Tom Feeney, Charlotte Indigo, Thomas Trostel and David Chilvers. And of course, a massive thank you to everyone who’s joined since last time too. Most important of all though, thanks very much for watching. Have a great week. And remember to just have a think. See you next week.

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*Источник: https://ekstraktznaniy.ru/video/36974*