99% of ocean plastic is missing 30:54

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Eric van Sibyl is an oceanographer at Utrecht University in the Netherlands.

But that wasn't his initial plan. When I went to university, I wanted to become the weatherman on television. And then during graduate school, I had the opportunity to go to sea. He was out there on a boat in the middle of the ocean for five weeks. Every morning I woke up, I would get a coffee, I would go to the deck, and I would just look over the ocean.

A few weeks into the trip, the captain called for man overboard practice. It was in the middle of the Atlantic Ocean, right? So it was beautiful weather. It was really nice. But it was, I think, the most scary thing that I ever did in my life. I'd been on that ship for four weeks. It was my home. It was the safest thing. And then the captain asked you to jump in.

I so well remember I was standing on the side of the ship and I thought like if I now jump in there's four kilometers of water beneath me. I've absolutely no idea what lives down there. I jumped in and I looked back to the ship. It was suddenly a very tiny ship in this gigantic ocean. And I remember looking back and thinking oh my god this is the only thing that can now bring me back home. It's a bit like I guess...

Going for a spacewalk, if you're an astronaut, I think that's the closest similarity that I was doing it in my swimming trousers in the middle of the Atlantic Ocean. That was the moment Eric decided to become an oceanographer. And he was initially curious about what he actually felt in the ocean that day. How the currents moved. How water moved from the southern tip of South Africa all the way through the Atlantic Ocean to the northern tip of Greenland.

And for that, I used the trajectories of drifting buoys in the ocean. Oceanographers have placed thousands of buoys with GPS trackers in the ocean. And Eric wanted to use them to map the direction of currents. The only problem was that any analysis that I did, all these drifters constantly ended up in these bloody garbage patches.

You might have heard of these patches, or at least the Great Pacific Garbage Patch. The Great Pacific Garbage Patch is a swirling mass of marine debris. The largest accumulation of ocean plastic on the planet. And the area it occupies is twice the size of Texas. Plastic enters the ocean from rivers or from harbors or from boats.

And it often ends up in one of five garbage patches around the world, which are held together by giant whirlpools of ocean currents. The water slowly circulates around there, making these gigantic rotational flows around the oceans. A group called the Ocean Cleanup is actually working on getting plastic out of the patches. And they found all kinds of debris there.

And all this plastic has prompted a lot of outrage. Perhaps most startling are the images of birds whose stomachs are filled with our trash.

Eric was curious how much harm this plastic was doing, exactly how it was impacting marine life. So he started looking at seabirds, just as an example. We knew already that there was a lot of plastic in the stomachs of seabirds. But what we want to know is, well, where do they get that? Eric figured it was the garbage patches. So he mapped out the patches, and his collaborators added a map of where seabirds forage. And the result was a map of where that interaction happens. And it was totally surprising because...

There were no garbage patches. There was all this plastic out there somewhere, but it wasn't in garbage patches. So we wanted to know, well, where is the rest of the plastic? And how much is out there? To start, Eric used an estimate of the total amount of plastic entering the ocean every year. Trying to understand, well, how does the waste management system in a country work? And that for all countries in the world is not easy.

But the best estimate we have right now is at least 5 million tons every year. Then Eric and his collaborators looked at data from boats that trawl through sections of the ocean, picking up nets full of plastic.

They count literally how many pieces of plastic is in the net. Eric combined that data with simulated models of ocean currents. We came to about 200,000 tons of plastic that we could account for in these patches. In other words, way, way more plastic enters the ocean than what ends up in the garbage patches. I thought that the garbage patches needed...

that they were the most important things in the ocean. But the total amount of plastic that we think is going into the ocean is at least 20 times larger every single year. So this is going on year after year after year. I mean, if you do the math, I would argue that it's probably less than 1% of all the plastic that has ever gone into the ocean that's still floating on the surface of the ocean right now. In other words...

99% of all the plastic is missing, right? We have dark plastic. Dark plastic. Like the astronomers have dark matter and dark energy. We oceanographers, we don't have an idea where most of the plastic in our ocean is. We've lost it. I'm Noam Hassenfeld, and this week on Unexplainable, if all the plastic floating in the garbage patches is only 1% of the plastic in the ocean, where's all the dark plastic hiding?

And what can we do about all that plastic if we don't even know where it is? So we've got this staggering amount of missing plastic. Those garbage patches, which people tend to talk about like they're the biggest problem of ocean plastic, they're just the tip of an enormous expanding iceberg. Just 1% of the plastic that's in the ocean. So what about that missing 99%?

Eric has some hypotheses about where it could be. One place we know that plastic ends up is in the bodies of marine organisms. But there we really have no idea how much is in there. And most estimates are that it is hopefully fairly low, only a fraction of all the plastic. But Eric says there's a few other places to look. Well, I think it is partly on the ocean floor. So people that go to the ocean floor and sample sediments...

they find plastic more often than not in the sediments in the deep sea floor. Is there any particular research you're thinking of there? Yeah, yeah, yeah. So there's a group in Germany, Melanie Bergman, and she organizes and maintains an observatory on the ocean floor between Greenland and...

And part of the work that we're doing is to look at the impact of climate change in the Arctic. And they have a camera there that's just constantly recording whatever critters pass by. We use camera surveys to look at the impact on large animals like starfish and snails, sponges, these kind of creatures. And she has over the years seen more and more plastic bags.

So it's three kilometers deep.

in the Arctic, every now and then you see a plastic bag drifting by and you think, oh, where are we, right? Why is this happening? Has she quantified any of this? What are the results of her research? Yeah, so locally she's quantified it and we've indeed quantified at different spots how much plastic there is. I found, for instance, that there was a seven-fold increase in litter on the seafloor between 2004 and 2017. Wow.

And the great majority of that is plastic. But because the ocean floor is so much more heterogeneous than the ocean surface, it is even more difficult to then get a total estimate of how much plastic is on the ocean floor. But we know that it is happening. But we know it is happening and we know it's there. And it's not entirely clear how that happens, because if the plastic is buoyant, if it floats...

When it enters the ocean, how can it at some point sink? And that's probably because algae start growing on it. The debris which is floating on the ocean surface becomes colonized with barnacles, mussels, all sorts of different organisms.

And at a certain point, it then starts to sink. — Maybe it's the chemical weathering of the plastic itself, so it becomes more brittle and therefore its density changes. — That's a theory. — But that's still a bit up in the air. — So if we're looking for dark plastic, a likely spot is at the very bottom of the ocean. — And the plastic, it has to get there from the surface. So there's probably also plastic in the water column. — This is another place to look for missing plastic.

It could just be floating somewhere between the surface and the seafloor. So these are mostly the microplastics. So plastic the size of a grain of rice or something, a few millimeters in size. Plastic that's barely even noticeable. So plastic starts big. It starts with an entire bottle or an entire plastic bag, and then it fragments. And it becomes smaller and smaller and smaller. And over time...

That means that you get more plastic because one bag ends up in thousands of microplastics and then maybe millions of nanoplastics. Now we know that the smaller plastic, they've got less buoyancy so they can more easily go with the flow. And I'm part of a study where we actually found the first evidence for nanoplastic pieces at five kilometer deep in the South Atlantic.

It's just floating around there. It's just in the ocean water. Finally, Eric says there's one last major place to look for dark plastic, even if it might not sound like ocean plastic at all. A lot of it is on coastlines.

And that still counts as ocean plastic? Yeah. So it's constantly washed back between the beach and then back out and the next high tide can get it back out into the open ocean. And that's also why a beach cleanup is so effective. Because a beach cleanup is not just about taking the plastic from the beach. It's also about preventing it from being washed back into the ocean the next time.

We're still under this umbrella of like dark plastic that you said. I mean, how can plastic on coastlines be missing plastic? That feels like you're telling me where it is, like it's on the coastlines. Well, yeah, no, so that's exactly the point, right?

I, as a modeler, and my colleagues, we don't know how much is where. We don't know how much of that 99% plastic is on the seafloor, how much of it is on coastlines, let alone that we know where in the world it then is. Yeah, how do we not know how much plastic is on the coastline? I mean, can't we just sort of...

look with satellites or something? Can we go to the coastlines? Well, we could, but then we have to report. I mean, a lot of people are going to the coastline and if they're good, then they would probably take the plastic that they see and put it in a dumpster, but they don't report it. That doesn't necessarily sound like a problem to me. I mean, is that a problem? It sounds almost like a success story. It is a success story if you care about...

reducing the amount of plastic in the ocean for sure. Absolutely. Yeah. But it's a problem if you're like me and you just want to understand where the plastic is, because otherwise, how can we ever start to solve it? And it may be, I mean, I would love to be back in a few years in your show and be able to tell, well, you know, the 99% that I told you about,

It turned out it was cleaned up already. We didn't have a problem after all. That would be an absolute success story. That would be fantastic. But until we have the data, we just don't know how much is on the ocean floor. We don't know how much is in the coral reefs. We don't know how much is in the sensitive ecosystems because we don't have the data. You know, talking about the reefs and the ecosystems, I realize I haven't yet asked you why this is so important. Like,

All of the plastic in the ocean, why is it a problem? That is a great question. And in fact, I find it a really hard question to answer. Coming up after the break, if we don't know where most of the plastic is, how can we know what kind of impacts it's having? And is there anything we can do? That's next. Support for Unexplainable comes from Greenlight.

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Exactly. How do you mean? Unexplainable. We're back. We've got this enormous unknown that Eric laid out. Even though those giant, swirling garbage patches might seem like the main problem of ocean plastic, they're only 1% of all the plastic in the ocean. Scientists have some general ideas where the other 99% might be, but they're just guesses for now, which makes fixing the problem even harder.

So to start working on the most targeted solution, scientists need to start with a basic question. What exactly do we know about how it's harming marine life? Yes, so surprisingly little. That's sort of surprising to me, given... We don't know a lot about really about harm. So what we do know is that plastic is harmful to corals. Okay. We know that if there's a lot of plastic in a coral reef, then it will more quickly get diseased.

We also know that plastic is harmful to seabirds. If they get it in their stomach, then it's just dead weight. But for many other organisms, there's little scientific evidence that it is really harming them on a species level yet. That it is really pushing entire species, say, towards extinction. There is a lot of good science about that theory.

plastic can potentially be harmful to organisms, for sure. I mean, at some point, if you feed an organism enough plastic, then it will die. Because it just fills up with plastic? Yeah. So biologists, what they're really good at is taking themselves an aquarium in a lab, putting their favorite species in it, and starting to feed it plastic. And at some point, you then get to a concentration where it's actually a lethal concentration of plastic, and that organism will die. Now,

There was an interesting study out of the UK a few years ago where two ecotoxologists actually then looked at all the data about at which concentrations these organisms actually die.

And that was, say, 10,000 or so pieces of plastic per liter. But in the real world, out in the open ocean, it turned out that the concentrations were up to 100 million times lower than the lethal concentrations. So is that to say that we know that certain levels of plastic can kill organisms, but we're not necessarily seeing it play out in a way that's...

endangering whole species or not yet? Well, yeah. An argument against it would be, well, but death is a rather extreme endpoint, right? Right. There would already be effects at lower concentrations, effects to fertility, effects to energy level, effects to all these kind of things for sure. But the thing is that we don't know. We don't know at which concentrations those effects start to happen for a lot of species. And it is because it is really difficult to measure that.

We do have whales who have beached and whose stomachs have shown up full of plastic, right? Or like various marine animals, right? Yeah, sure. There are a lot of whales that beach with a stomach full of plastic. But then, of course, you have to ask yourself, well, did the whale actually die because of the plastic? Or...

Is it the other way around? And so there's a hypothesis out there by a colleague of mine, and it may actually be that whales or dolphins or whatever organisms that are sick, they don't have the energy anymore to chase fish. The only thing that they can still catch is plastic. So maybe that the whales that we see on the beach with a stomach full of plastics are the ones that have just started eating plastic because there's nothing else for them to eat.

Again, plastic is probably not good to an organism, but I would push back a little bit against the underbelly feeling that all plastic is bad to all organisms. It's more difficult than that. And I think that we should do more rigorous science and more rigorous analysis on what really happens.

and how really the interaction between oceans, plastic and organisms, how that actually impacts ecosystems. Because it is really much more complicated than what you would see by looking at a whale full of plastic. You know, I feel like a little reluctant asking this to an oceanographer, but when we think about the problems to ocean ecosystems, from the perspective of someone who

lives in Kansas or who lives in Afghanistan, you know, somewhere far away from an ocean. Why is that an important problem from their perspective?

Yeah, because the ocean is absolutely crucial to everyone's well-being. And you don't need to live near the ocean to get the services that the ocean provides. And that is partly the oxygen it provides. I mean, we think about the Amazon as the lungs of the world, but the ocean is a far bigger lung. Half of the oxygen that we breathe is produced by algae in the ocean.

And the ocean also provides a huge service in terms of drawing down carbon dioxide. If the ocean wouldn't be there, we would have a much, much bigger climate impact right now already. So we should care about the functioning of the ecosystems in the ocean, everyone. And you don't need to live next to an ocean to care about that.

And are all those ecosystems kind of intertwined in a way that we don't fully understand and could have sort of existential effects to the ocean as a whole if they're disrupted by plastic? Absolutely.

Like with any ecosystem, it's the smallest critters that are the most important ones. Those are the ones that are at the base of the food web. Those are the ones that are the most numerous. The photos are always of the whales and the large organisms, but it's the tiny organisms, it's the plankton that are really doing the hard work, that are really putting all these surfaces that we care about at the forefront. Given how much of a potential problem plastic could cause to the ocean,

What can we do about the dark plastic? Like, what can we do about the plastic we don't know about? Yeah.

So we may hope that a lot of that has been cleaned up already from beaches. So my guess is that it could easily be up to, I don't know, a third or so of all that plastic that has just been removed from beaches already. That's good. That's good news. But the other two thirds is going to be there. And a lot of marine biologists think that actually at some point or already bacteria have evolved to start eating that plastic.

We know that there are bacteria that can eat oil in the ocean. The Deepwater Horizon oil spill, a lot of the oil that came out of that well was actually eaten away by bacteria.

And from eating oil, it's not that big a step to start eating plastic. So at some point, if there's enough plastic in the ocean and it is there long enough, then I would also imagine that there would be evolutionary drive to just start utilizing that as a resource. And as a society, is there anything we can do besides hoping for bacteria to evolve? Yeah.

I don't think we can do very much. The plastic that's out there is out there. If it's on a beach, for sure, pick it up because you remove it from the ocean in a sense. But really going out there and spending all the carbon fuel and spending all the energy and all the effort and disturbing the ecosystem by trying to take out the plastic because it's not...

clean plastic, right? It's plastic that is surrounded by a layer of algae, by fish that have laid their eggs on it. I mean, the plastic has become part of the ecosystem. At some point, we can't take it out anymore because if we take out all this micro plastic, we inevitably also take out all the life that's associated with it.

Ultimately, what we have here with ocean plastic is an extremely large unknown without an easy solution. We don't know where the dark plastic is. And partially because of that, we don't know just how bad all this plastic might be. But even though the extent of that harm is unknown, the fact of the harm itself — that plastic is bad for the ocean — that's pretty clear. So for sure we need to stop putting plastic in the ocean.

I mean, it's better to have an ocean without plastic than to have an ocean with plastic. There's no question about that. And even though we can't easily just take it out of the ocean, there are still things we can do when it comes to cleaning up all the dark plastic. There are beach cleanups all over the world. There are researchers thinking through how to use plastic-eating enzymes without negative consequences to the environment. And there's even scientists thinking through how to turn floating plastic into fuel for ships.

But given how little we know about where all the dark plastic is, these efforts likely won't be able to solve the larger issue anytime soon. So we might need to start further upstream. I think we should stop it from entering the ocean. We have to stop entering it into the environment in general.

It sounds like a clear goal, but as soon as you start thinking through what it would take to stop plastic from entering the ocean, it starts getting pretty complicated. The most basic way to keep plastic out of the ocean would be to just make less of it. Yeah, so I feel that a lot of plastic that we see in our society right now is useless. But I also think that we shouldn't

go to the extreme of minimizing the amount of plastic, because I do see a lot of good uses for plastic. In places you might not expect. There was an interesting paper that found that just because of the plastic that surrounds the cucumber in the supermarket, the amount of CO2 that's emitted in the processing and in the calories of the cucumber are five times lower than

than without a shrink wrap. Essentially, shrink wrap stops cucumbers from going bad, preventing waste, which means there's more emissions per cucumber without the plastic. I think you could make the case that we can't solve the climate crisis without sometimes using more plastic. So we probably shouldn't stop making all plastic, but we can certainly make a lot less of it, especially when we can replace it with other materials.

After that, it might come down to fixing our waste management system. The fact that you and I and everyone else, if we throw a piece of plastic into the waste bin, that we are not 100% sure that that will never enter in the environment, that is the problem.

And that is also where the fix should be. Plastic often enters the ocean from rivers and harbors, and there are some systems there that try to collect the plastic before it reaches the ocean, but they're far from perfect. And the same could be said for our recycling system in general. Far too much of our plastic just

just isn't recyclable to begin with. - Well, not yet. That's the technological challenge. And I put that to the technology experts, go and make it happen. - But banking on a technological fix to save us, it's a risky proposition. That type of mindset can just lead people to keep polluting with the vague hope of a savior down the line.

So in order to avoid that outcome, we can try and we are trying all of these things together. Making less plastic, beach cleanups, technological innovation. None of this is hopeless. Yes, I do have hope because I think that we're not too late.

The amount of plastic that has entered the ocean so far is an atrocity, but it is not fatal yet. We are well before the tipping point, I think, and that means that we can still change things. That if we reduce the amount of plastic entering the ocean, well then, yeah, for sure we still have some plastic lingering for decades, but it's probably not that harmful yet. So we can still do something about it. ♪

This episode was reported and produced by Noam Hassenfeld. We had edits from Catherine Wells, Brian Resnick, and Meredith Hoddenot. Music from Noam, mixing and sound design from Christian Ayala, and fact-checking from me, Richard Sima. The rest of the Unexplainable team includes Bird Pinkerton and Manny Nguyen, and Liz Kelly Nelson is the VP of Vox Audio. Special thanks to Chelsea Rockman, Andrea Thompson, and Laura Bolt.

This episode was actually based on Laura's video for Vox. It's called Why 99% of Ocean Plastic Pollution is Missing. You can find that on Vox's YouTube channel. If you want to get in touch, please email the team at unexplainable at vox.com. And if you feel like leaving us a nice review or a rating, we'd really appreciate it. Unexplainable is part of the Vox Media Podcast Network. We'll be back next week.