In Our Time - The Mariana Trench

Episode Date: February 19, 2026

Misha Glenny and guests discuss one of the wonders of the natural world. In 1875 in the western Pacific, the crew of HMS Challenger discovered the Mariana Trench which turned out to be deeper than Everest is high, by two kilometres. Trenches like Mariana form when one tectonic plate slips under another and heads down and there are around fifty of them globally. While at one time some thought it was too dark and deep for life there and others wildly imagined monsters, the truth has turned out to be much more surprising. With Heather Stewart, Director of Kelpie Geoscience and Associate Professor at the University of Western AustraliaJon Copley Professor of Ocean Exploration and Science Communication at the University of SouthamptonAnd Alan Jamieson Director of the Deep Sea Research Centre at the University of Western AustraliaProducer: Simon TillotsonReading list:Susan Casey, The Underworld: Journeys to the Depths of the Ocean (Doubleday, 2023) Jon Copley, Deep Sea: 10 Things You Should Know (Orion Books, 2023)Hali Felt, Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor (Henry Holt & Co, 2012)M.E. Gerringer, ‘Pseudoliparis swirei: A newly-discovered hadal liparid (Scorpaeniformes: Liparidae) from the Mariana Trench’ (Zootaxa 4358 (1), 161-177, 2017)A.J. Jamieson, The Hadal Zone: Life in the Deepest Oceans (Cambridge University Press, 2015)A.J. Jamieson et al., ‘A global assessment of fishes at lower abyssal and upper hadal depths (5000 to 8000 m)’ (Deep-Sea Research Part 1. 178: 103642, 2021)A.J. Jamieson et al., ‘Fear and loathing of the deep ocean: Why don’t people care about the deep sea?’ (ICES Journal of Marine Science. 78: 797-809, 2020)A.J. Jamieson et al., ‘Microplastic and synthetic fibers ingested by deep-sea amphipods in six of the deepest marine environments on Earth’ (Royal Society Open Science, 6, 180667, 2019)A.J. Jamieson et al., ‘Bioaccumulation of persistent organic pollutants in the deepest ocean fauna’ (Nature Ecology and Evolution. 1, 0051, 2017)V.L. Vescovo et al., ‘Safety and conservation at the deepest place on Earth: A call for prohibiting the deliberate discarding of nondegradable umbilicals from deep-sea exploration vehicles’ (Marine Policy. 128, 104463, 2021)J.N.J. Weston et al., ‘New species of Eurythenes from hadal depths of the Mariana Trench, Pacific Ocean (Crustacea: Amphipoda)’ (Zootaxa. 4748(1): 163-181, 2020)In Our Time is a BBC Studios ProductionSpanning history, religion, culture, science and philosophy, In Our Time from BBC Radio 4 is essential listening for the intellectually curious. In each episode, host Misha Glenny and expert guests explore the characters, events and discoveries that have shaped our world.

This is In Our Time from BBC Radio 4, and this is one of more than a thousand episodes you can find in the In Our Time archive. A reading list for this edition can be found in the episode description wherever you're listening. I hope you enjoy the programme. Hello, in 1875 in the Western Pacific, the crew of HMS Challenger discovered the Mariana Trench, which turned out to be deeper than Everest in the Western Pacific. is high by some two kilometres. Now, trenches like Mariana form when one tectonic plate slips under another and heads downwards towards the earth's mantle,

and there are around 50 of them globally. Now, some people used to think that it was too dark and deep for life to exist there. Others imagined monsters lurking at the bottom of the ocean. The truth has proved to be more intriguing than either of those. with me to discuss the Mariana Trench are three people who were all veterans of this kind of environment. Alan Jameson, Director of the Deep Sea Research Centre at the University of Western Australia. John Copley, Professor of Ocean Exploration and Science Communication at the University of Southampton. And Heather Stewart, Director of Kelpie Geoscience and Associate Professor at the University of Western Australia.

Heather, I'd like to come to you first. Can you just describe the Mariana Trench to us? How big is it? Where is it? And if we could see it, what would it look like? Yeah, fantastic. The Mariana Trench is what's called a subduction trench. And what it looks like is this long, curved, deep within the Western Pacific. And that's formed as you introduced through a process of plate tectonics.

So we have denser oceanic lithosphere, so the Pacific Plate. That plate encompasses the entire Pacific Ocean. And that is being thrust and pulled underneath the adjoining continental plates. So this process of plate tectonics by which these oceanic plates are getting taken down into the mantle and recycled, that downward flexure causes these ultra-deep parts of our world. Most famously, the Mariana Trench and the other. trenches that surround the Pacific, the so-called Pacific Ring of Fire. And that's how these ultra-deep places are formed.

And the maximum depth of the Mariana Trench is 10,925 metres. And that's about 98 times the height of St Paul's Cathedral, which is just, it's a really hard number to sort of visualize in your head when you start to think about these sort of deep water environments. And how long is it exactly? It's about 2,550 kilometres long and it sort of arcs around the Mariana Isles in the Western Pacific there. Now, you're all experienced divers in these terrains. Heather, what's it like to go down a trench? It's absolutely incredible. I mean, all three of us around the table here have been in submersibles.

But from my personal point of view, there's the moment when you're sitting on the sea surface and you get the, the clear-to-dive call. And that colour change as you start to fall through the water column and the change from the sort of clear waters on the sea surface through the brightest shades of blue down to absolute pitch blackness. But then, of course, all of that, you're sitting in silence. And that is so humbling as well as very, very exciting. Because, of course, after a few hours, you start to come to the seafloor

in these sort of deep subduction trenches. And I've been lucky enough to dive to the bottom of the Tonga Trenches. But that moment when you turn on the lights of the submersible and you start to see the seafloor coming up underneath you is absolutely fantastic. And as a geologist, knowing that you're the first person to set eyes on this seascape, if you will, but also starting to look and your brain is already starting to process what you're seeing out of the viewports and trying to put that into some sort of geological context. Are we landing on sort of soft sediment seafloor or are we coming down on rocks?

what type of rocks are there? Are there any structure in those rocks? Are we seeing faults? What life is encrusting and are being associated with that habitat down there? So you're constantly taking this information in and trying to form a sort of hypothesis and that you're testing during the submersible dive itself.

But I mean, it's absolutely, you know, the very first dive I did, the pilot sort of joked that, you know, you had to turn up the oxygen because I was getting very excited. So I was using up more oxygen in the environment inside the sub. but it's truly, you know, the being there and sort of seeing it yourself is something that can't be replicated through other means. Fascinating. And Alan, I believe that you have gone amongst our guests the furthest down the Marianna Trench. Can you tell us about that experience?

Yeah, it was a good few years ago now, but it was a mistake. I was not really supposed to do it. How can you go down the Marianna Trench? by a mistake. You woke up one morning. It wasn't planned. We went there to do, I think it was four or five dives on the deepest place on earth.

I think the first one was the third time has ever been done and no one thought we'd ever do it. We'd probably get one in, maybe two, before the sub breaks or we run at a time or there's weather or whatever. And for some reason we just did one every two days for a week and we ticked all the boxes because some of the dives are to do with the classification

of the sub. Some of them because of the owner wants to do it at the time. Other ones were to do with the manufacturer. and we did four and nobody expected us to do that and so interesting the guy called Don Walsh who was the guy who did the first dive ever

in 1960 he was with us and he came in one day and said there's another one there's another one do you want to do it and it's like yeah sure yeah and they said well where do you want to dive and I said well I don't really want to dive challenge of deep because we've just done it four times

and there's actually nothing much there that's the deepest bit of the the merriam challenge deep yeah we've done it 22 times now so I was right there isn't much there but I said I want to go next door. There's a place next door called Serenity, which is like 10,700, and there was reasons to believe it would be slightly more interesting.

So, yeah, and before or not next morning we were down at 10,700 and something metres, and we found these big sulphur mounds and all sorts of interesting stuff. It was brilliant. So it wasn't planned. It wasn't really supposed to happen. What are the challenges for the submersibles themselves? I mean, because they must be operating under immense pressure, and yet they've got to sustain an environment in which you,

humans can live or exist for four or five hours or whatever. Yeah, there's two parts to it. So we've gone down to environments which are pressure-wise are about one ton per square centimetre, if not a bit more. So the engineering for that is actually relatively easy because it's linear. So you just make things thicker and thicker. We use titanium inside the sphere

and we use all sorts of materials that can get us back to the surface and so on. But the other problem we have is not just the pressure at depth is actually the distance from the surface. So communication with the surface is very difficult. For all sorts of safety reasons, we have protocols in place where we have to contact the surface every 15 minutes. Every half hour it has to be a voice one.

So we have an underwater telephone where we can talk to the surface. That's the biggest problem is trying to punch an acoustic signal through seven miles of water and then trying to listen for them coming back. And we've kind of nailed it now. But some of the other problems we have is tracking. It's quite often, well, up until recently, there hasn't been any products on the market that we can use to track where the sub is. So for the last five, six, seven years, we've been doing it with no tracking at all.

so we've got very rudimentary tracking but not like you would in shallow water so there's a certain degree of challenges to do with just being very very far away from the ship as well as the pressure at the bottom How does the sound travel back and forth between the ship and the submersible? We have a thing called an underwater modem

and it's an old Australian military device that we push a button and say hello and then you release the button and it scrambles it into the acoustic signal goes up and you can kind of tell it's weird it scrambles it into acoustic signal but you can tell who's talking It's really bizarre.

You can almost hear the accent in it. And then they hear it and then they talk back. We've got text message now as well, which is quite nice. John, these depths are often called Hidal Zones. What does that mean? What is a Hidal Zones? It's from the Greek for Hades. So the idea is this is the greatest depths of the ocean.

So there are these popular schemes for dividing the ocean up into different depth zones and giving them names. but environmentally ecologically, most of them don't make sense. The Hadle zone is one that in a way does make sense if we just say, well, that's ocean trenches. Ocean trenches tend to start at about 6,000 metres. But that said, there are some environments in the deep ocean that aren't ocean trench, which are at more than 6,000 metres, which is where the zones kind of break down. But in a way, you can think of it as a shorthand for being ocean trenches.

Right. That's nice and simple. How was it discovered? The Mariana trench. in particular. So you mentioned in your introduction HMS Challenger. So this is a global voyage of discovery in the early 1870s. And it has two main goals. One is scientific to map the ocean floor,

understand its undulations and the extent of life in the deep ocean, and also a strategic goal as well. And that's to scout the routes for submarine telegraph cables, which are such a huge technological revolution of that time. I mean, I think right up there with the invention of the printing press and the impact they had on the world. So we had telegraph cables across the Atlantic in the 1860s. The last thing was even more challenging.

Exactly. And people wanted to wire up the British Empire. So one of the goals of HMS Challenger, and the reason that it got funded was this strategic goal. Anyway, 23rd of March 1875, HMS Challenger has been, it's in the Pacific, and it has been pushed off course by baffling winds, as they record in their log.

And they decide to make a depth measurement where they've ended up. So they lower a weighted line. and they record a depth of 4,475 fathoms, which is 8,184 meters, I think. So that was the deepest place that they measured on their voyage. It's not actually the deepest point in the ocean, and it's not even the deepest place that had been measured at that time. So where they made that measurement, they were actually about 25 kilometres

from what we now recognize as the deepest part. of the Mariana trench, the Challenger Deep, and about 2,700 metres short of that. And it wasn't then thought to be the deepest part of the world's oceans, because a year earlier, a ship called the USS Tuscarora, which was also scouting submarine telegraph cable routes in the Pacific for the United States, had measured 8,513 metres for much further north than the Pacific in what we now recognise as the Kural Kamchaka trench. So HMS Challenger found this deep depression, literally by accident,

near the Mariana Islands. And there were no other depth measurements in that area for another 24 years. So they found a deep spot. They didn't know it was part of a trench. It wasn't called the Mariana Trench at all at that time. And it wasn't even the deepest known point at that time. So if we jump forward a little bit, 1894, HMS Penguin measures just over 9,100 meters in the Southwest Pacific in what we now recognize as the Kermodeck Trench.

So that then becomes the deepest known. place on earth. But not for very long, 1899, a ship called USS Nero, again scouting submarine cable routes near the Philippines, measures 9,636 metres. That becomes the deepest known place on earth, what we now recognise as the Philippine trench. And that stayed as what people thought was the deepest place on earth until 1951. And these were individual depth measurements, and people didn't realise they were part of these trenches and these features that Heather's described. That came also, though, at the end of the 19th century. So there was a map published of the depths of the world's oceans by a cartographer called Alexander Supan.

And he showed that some of these places where there have been these big depth measurements were trench-like features. Not actually the Mariana one on his map, but he identified the illusion trench. And he also proposed that these things should be named after the geographic features that they're near to, so that people don't get confused. So that's why Mariana turns out to be Mariana, because it's, near the Mariana Islands. Indeed. And Challenger Deep, which is what it was called before on an earlier map in 1877, that becomes eventually the deepest known bit of the Mariana Trench. Heather, what do we see when we get down to the bottom of the trench on the beds of the trenches

in geological terms? Is this like a sort of conveyor belt of rock? Yes, indeed. In that sort of really large-scale, big geological processes, frame, then we're looking at a conveyor belt of oceanic plate coming into the trench being bent and thrust down underneath that overriding plate. So that's where we get that conveyor belt. But in terms of when we're actually looking at the seascape, you know, it can vary quite a lot. So we have what are called hemipelagic and clay-rich sediments that drape that seascape, that topography of rock. But once we're actually in the trench, you know, we don't only have that oceanic plate which are composed of volcanic rocks like basalts and things.

We actually have the fore arcs. So all these rocks and sediments are also getting scraped off onto the overriding plate as it's being subducted in. So we get this melange of sediments and rocks, but we can also see bits of exposed mantle in these trench environments as well. So these are sort of gabros. What does mantle look like? It's actually really cool. And we've got some amazing footage of that. And it's these massive dark rocks but they've got really big major faults and joints in them. So I mean it's very characteristic and it's got a lovely sheen to them as well. So in terms of what you're looking at

out of the viewports and what you're looking back on the video that's recorded, it's a very striking environment. But what's also really cool is that when the process of subduction is happening, it almost starts this catalyst of other things that are happening. So we see mudduring. volcanoes and we see vent systems. You know, there's a, the Shinkai vent system is on that fore arc of the Mariana Trench. And it's not like what we might think in terms of black smokers and, you know, those amazing documentaries that we see where you've got that sort of pump of black material kind of coming out of the seafloor and those very dark brown big edifices and stuff. These vent systems in the Mariana, the Shinkai vent system, for example, are made out of carbonates.

So they're white, pristine white chimneys that are preserved on the seafloor. And the fluids that are erupting from these systems are being sampled and tested for the chemistry. So we're looking at what minerals are being dissolved by the water that has been taken down by this process of subduction and is percolating through the rock mass. And it's dissolving out all of these minerals and then it's re-precipitating them. And that's when Alan was talking about the sulphur mounds in the serenna deep. you know, the sort of bright yellows. I mean, the colours that you can see on the seafloor can take your breath away.

Some of the other footage that we have from the Java trench, for example. I mean, Alan, we've got yellows and blues and all of these hemisynthetic bacteria that are living off the mineral content coming out of these vents and the cracks and fissures on the seafloor. And just explain to us quickly what turbidity currents are. So turbidity currents, you might like to think about them, as underwater waterfalls, where we've had something, whether it's through gravity, so it's just, you know, you've got a slope that is being loaded with sediment,

much like whenever you're driving through the highlands and you look, especially after heavy rainfall, you might see the sides of the glen that you're driving through. You know, you can see the material is sort of slipping downslope. So we can get the same comparable processes underwater in these trench systems as well. But then, of course, we've got the more dramatic, perhaps the more sort of well-known events that are triggered by earthquakes or volcanic eruptions, for example. But basically these trigger movement of vast quantities of material downslope, huge speeds as well.

And it is a really great mechanism for transporting not just sediment from higher slopes down into these trench basins, but also it's transporting food and nutrients for the communities that live down there. Well, let's go on to those communities. And Alan, let me ask you, what kinds of life are we seeing at these depths? There's all sorts. So you can kind of categorise all deep sea animals

in the two different categories. There's those that go down to about 8,000 and there's those that go beyond that. So when you look at things like fish, prongs, urchins, brittle stars, sea stars, squid, octopus, you find all them deeper than 6,000 metres, but they rarely ever go beyond eight. So obviously there's a barrier there,

which is quite difficult. If the species is adapted to high pressure and go beyond that, all the way and they don't seem to care about pressure at all. So there you've got things like little tiny hoppers called amphipods. There are things called isopods and polychaets which are pill bugs and scale worms

and there's normal looking jellyfish. There's anemones down there. But once an animal seems to have evolved to break the 8,000 metre barrier, it almost adopts this complete resilience to pressure. And sometimes their depth range can be 5,000 metres, which is incredible. So at the very, very bottom, there's one animal

which I think has become kind of really important to us, because we're finding it at the bottom of every single deep trench we go to. And you have to be deeper than about 8.5 to 9,000 meters to see it. And it's just an anemone. It's called a Galathianthemum. And they live in a little tube. And they look like a little white flower. Really quite beautiful looking thing.

But we can't find them anywhere else except at the very deepest points of the really deepest trenches. So there's that. Everything else tend to be quite small at the deepest points. But as I say, when you get to 8,000, there's quite a lot of large animals still kicking around, which is people find quite surprising. And they don't look weird. if anything kind of goofy And you

I believe you discovered or named one called the snail fish Oh the snailfish is a known family We discovered the mariana snailfish We discover heaps of fish We just don't name them anymore Because it's too difficult But yeah we find snailfish all the time So we named the mariana one

Because it was quite prestigious So for quite a few years It was the deepest fish in the world Unfortunately it's not anymore There's one further north of Japan Which is slightly deeper But they're all kind of the same They all look goofy and weird

and that's sort of flaccid-looking little things. But they are the deepest in the world. And weirdly, the family of fish of snailfish are not actually deep sea fish. They're shallow water fish. They've completely taken over. So there's 300 species. You find them up estuaries and stuff.

And snailfish are now 1,000 metres deeper than actual proper, well, I like to consider proper deep sea fish. John, how do these animals and the anemones and so on, how do they withstand pressure at 10,000 metres below? How does it happen? Well, the challenge of pressure. pressure for animals in the deep sea is really often not what we perhaps imagine it is. So, I mean, to illustrate that, the last expedition I was on in the Arctic, we took an ordinary

uncooked chicken egg and we sent it down to three and a half thousand meters on the outside of one of our deep diving vehicles. That's about the average depth of the world's ocean. And it came back without a crack on it. And that's not because it's somehow stronger than our submersibles. You know, we then cracked it open in the galley to show that it was an ordinary egg. That's because, think about that chicken egg, what's it made of? It's made of solid matter for its shell and it's filled with liquid. And those are pretty much incompressible forms of matter. You know, if you imagine dropping a stone into the Mariana trench,

it sinks down to the ocean, it doesn't at some point suddenly implode because there's no gas-filled space inside it for it to get squashed down into by the pressure. Similarly, with liquids, if you get a syringe of water, you know, stick your thumb over the end and try and push down that plunger. you won't budget compared to a syringe of air, the same kind of thing. So for deep sea animals whose bodies are made of solid matter in their tissues, liquid body fluids, in a sense they're not mechanically withstanding pressure, a difference in pressure between their insides and their outsides,

in the same way that our deep diving vehicles do. Our vehicles have to maintain, you know, a gas-filled space inside them at normal atmospheric pressure, either to keep us alive as occupants or to keep electronics dry if it's an uncrewed vehicle. But it's not like that for deep-sea life. there is a challenge but it's about what happens with molecules in cells but it's not about mechanically with with standing pressure can you just go into that a bit about the molecules in the in the cells because they act in a rather different way than the molecules in our cells do

so some of the problems with pressure for example involve protein molecules folding up into the right three-dimensional shape that they need to be to work as enzymes and you know we need the enzymes and they're carrying out all the living processes in cells. And that's a big problem because high pressure traps water molecules on the unfolded protein as it's been kind of put together inside the cell and prevent it from folding up into the right shape to do its job. So that's one challenge of pressure. And so a lot of deep sea animals have these small molecules that we call chaperones that help to pull the water molecules off the unfolded proteins. So they fold up into the right shape. Sometimes the

animals have a different kind of protein structure. Their protein is made of a different sequence of these little bead-like amino acids, which again helps them form the right structure under pressure. And it's also the cell membranes, the things that enclose the cells. Now, that's normally a very fluid, bilayer of lipid molecules, fat-like molecules. Under high pressure, that can become very rigid, and that can stop, you know, messages getting in and out of the cell and so on. So again, a lot of deepsy animals have different composition of lipid molecules in their membranes to overcome that. So a fundamentally different, even if you're path from, say, humans?

Well, adaptations. Adaptations to their environment, just tweaks, if you like, as to, you know, nature coming up with a solution to these challenges. Heather, back to what we were talking about, you mentioned the landfalls and earthquakes and volcanoes. How stable is that? And does that impact on the animals living at the bottom or in the trench? In terms of stability, I mean, it is a very dynamic. environment, you know, being part of the ring of fire, the Pacific ring of fire, of course, you know, we've got volcanic eruptions, we've got volcanics going on, we've got the earthquakes

and everything. It is quite what we might call a sort of slippy boundary at the Mariana. So we don't, we see a lot of earthquakes. I mean, it is an active subducting margin, but it's not stuck. There are other margins that are sort of become stuck. And then we've got a huge buildup of geological forces that are trying to sort of unstick that margin. That's where we can. get these huge earthquakes that cause such devastation in places. So in terms of the mariana... So those earthquakes trigger tsunamis and things like that? And they can trigger tsunamis, for example, yeah.

So as I was saying earlier, in terms of keeping the movement of nutrients and sediments from the shallower fore arc down into the trench basin, so that's a constant evolving and occurring process. So it is constantly changing. And we've got some amazing footage from up and round the corner a little bit, the Japan Trench, where you can see rock failures and the block failures. So going back to the basics of sort of geotechnical elements, we can see that happening, not just in this rock mass,

but also with this semi-consolidated. So the sediments that are a bit stuck together and are starting to behave more like a coherent rock than a soft, squishy substrate. And we can see those failure planes and mechanisms happening as we traverse in the submersibles and the remotely operated vehicles that we're using. Alan, what happens when you go down there? What do you see?

Is it a pristine environment? No. Sometimes there are places that look very pristine, but I mean, I've probably done about, probably over 30 dives now, and I don't necessarily recall any dive that haven't seen something man-made. Probably everyone.

Maybe there's one or two that haven't. Some of them are really bad. So I remember doing a 10,000-meter dive on the Philippine trench, which was the spot where the Galathea expedition in the 50s had found a rock, which was a Galathean, Galatian, by the way, the one I was mentioning earlier. So we dove on that spot and we filmed them alive and thought that's great. But we also saw something like 19 plastic bags on the same dive. Just floating around, you could read the logos off them.

There was an eco-friendly plastic bag came past. You're like, really, how eco-friendly is that? How eco-friendly is that? And then there are other dives where it's more serious So going back to Marianna Trench Dive in the Challenger Deep, the whole western side of Challenger Deep which is where Donan, a guy called Picard Dover in 1960s, is now a no-go-zone because that whole area is just covered

in discarding fiber optic cable. And so someone in the last 10, 20 years, maybe it's got something to do with listening to the naval base on Guam or maybe it's in guys in the military, I don't know, but people have been doing a lot of experiments at the deepest point. and now we have hours and hours of footage of fibroptly cable either just discarded or actually tot and tight across and if you're in a self-propelled vehicle like a sub

you do not want to be anywhere near fibro optic cable very very dangerous and it's everywhere now but it's only on Challenger Deep but it's not anywhere else in the Mariana and it's not seen anywhere else in any other trench so there are things like that where that's kind of almost deliberate someone's been doing something there

but one of the weirdest ones I think was last year we were down 5,000 metres somewhere just on the equator and four days north of Samoa and we were driving along and doing the usual thing I was telling the pilot they'd go and have a look at this

going to have a look at this, go and have a look at this, and we saw this red thing and thought that's weird, I wonder what that is and it's going to have a look and pulled up alongside it and it was just a packet of Chinese cigarettes just lying there thousands of miles away from anywhere as if someone had just dropped them out of their pocket

and you know it's bizarre it's really quite bizarre It can really throw you as well when you're sort of going to like because you're so focused on trying to record as much scientific data and information and the commentary that as you're going along

on the seafloor and then out of the gloom you sort of see something and I think, you know on the Nova Canton Trough as well I had a dive at six and a half thousand metres and I sort of said to the pile I was like oh God there's something over

like that's going to be and it was a cardboard box it's just you know you're like oh oh sugar I've just like deviated from the plan because I thought that was going to be something you know geologically or ecologically monument and it's like oh okay yeah

The Porto Rico Trench was probably bad. Oh yeah, that was terrible. Had gates and magazines and plates and coat cans and beer bottles. But I mean, it's sitting in Hurricane Alley. So I think when these hurricanes, it's not necessarily a story of human folly. I think when you have tsunamis and hurricanes, a lot of material just goes offshore. And if you happen to be next to a trench, it's going to end up there.

And it's quite depressing to see it. Although the point you make about fibre optic cables on Challenger D seems to me to be quite interesting. The coolest thing about Marianan, in terms of man-made naughtiness is there's an SR71 blackbird you know the old aircraft from the 1960's a big black really cool looking thing and one of them crashed

they didn't want the Chinese to get it so they took it out of Guam out to the Mariana and threw it off the back you can see pictures of it online so somewhere in the mariana there's a blackbird which would be the coolest I've ever I beg to differ you know I'm sure they haven't released the coordinates for exactly where it is I bet the Chinese have found it

just not telling anyone John, I want to come back to the animals down there. How do they feed? What are they feeding on, apart from human junk? Most of the time, they're feeding on what rains down into the trench. And trenches are interesting because they act a little bit like a funnel. In that there's this stuff that has the poetic name Marine Snow. But basically, it is poo of all the animals that living in the ocean,

and it is dead bodies of all things living in the ocean. And this marine snow sinks down. It does get concentrated in the trenches through this sort of funnel effect. And so the bottom of your trench, I mean, it's a combination of both a toilet and a mortuary, but that's what things will make a meal of. And they'll make a meal of anything that they can.

So, oddly enough, some of the animals that live at the bottom of the trenches are able to digest things like wood, which a lot of animals in the ocean don't bother with. It's quite hard to kind of crack the molecules in wood. to make a meal of it. But if that sinks and nothing has eaten it on the way down, and that's what you get at the bottom of the trench, then there's a strong driver for any organism that can make a meal of it.

Now, there are some places in trenches, though, that are really exciting where there are chemical-fueled islands of life that break all the rules. So what we call cold seeps. As Heather mentioned, where you've got these plates subducting, you get the sediment being scraped and squeezed on the subducting plate, and that squeezes whatever's in that sediment, out of it. And so if that's had rotting organic matter in it over, you know, many, many

millennia, that's broken down into methane. Methane gets pushed out of the seabed. You get these what we call cold seep communities. And that's where life is incredibly abundant. Now, they haven't been seen yet in terms of animal colonies in cold seeps in the marianas, but they have been seen in the Kurokamchaka and the Aleutian trenches, more than 9,000 metres deep, which are the deepest known islands of this chemically powered life, which we have on Earth, which are hugely exciting. Alan, from a scientific perspective, Mariana must be an achievement to go down there.

But is it the most interesting scientifically, or is it just the feather in your cap of having been deeper than anywhere else? It's a bit of both. It's certainly not the most interesting. I think it's most prestigious. And it's sometimes when you have something with a prestigious name to it,

it does kind of cloud the reputation it's got and stuff. From a purely scientific point, I think we've spent a lot of time going to other trenches. We've done Marianna about six times, but for various different reasons and different boats and different nationalities or whatever. There's been reasons for doing it, but no one trench represents all other trenches. And so it's the deepest one, therefore it's an outlier. It's not the same as the rest of them because it's deep within them. The biggest problem in Mariana we've got is that one of the only big trenches in the world that does not lie along a coastline. So all that organic matter that comes into the surface that rains down is food, it's the only one that doesn't have it.

The rest of them are somehow attached or associated with the continental landmass. It's also quite low to the equator. And so there's not a lot of food on the surface there anyway. So it is what we call oligotrophic, which means it's in an area of the ocean that doesn't have a lot of energy. And it doesn't have any seasonality. And so there's lots of reasons why Mariana doesn't represent anything other than the fact it's super deep. So if the question you're trying to ask is what happens at mega deep depth, I guess it's your one.

But if it's the question is what happens in trenches or what happens across a massive depth range, there are many other places you need to go to as well. The analogy I always use is like if you're trying to understand high altitude biology or high altitude flora and fauna, how much would Mount Everest tell you about every other mountain in the world? Not very much. You'll tell you a little bit about biology,

but I wouldn't tell you anything about a mountain goat in Kilimanjaroat, right? So do I get, John, in that case, it's the implication of what Alan's saying that the environment in Mariana is actually very static and constant compared to others. It depends on what time scale we're talking

here. Now, everywhere in the deep ocean is changing as a result of impacts of human activity. So climate change affects all of the ocean, including the deepest depths in the ocean. And it affects it in several different ways. I mean, we are getting warming of waters

and that is getting deeper. and so on. But fundamentally for deep ocean, what's changing is the flow of oxygen that reaches the deepest parts of the ocean. So all the animals that we've been talking about, they're animals. They need oxygen. The oxygen's dissolved in seawater. Where does that oxygen come from? Well, it dissolves from the atmosphere into the ocean in the polar regions, the surface, where dense, deep currents form and sink, and then they spill out across the ocean basins. So life at somewhere like the bottom of the Mariamer trench, the oxygen that those animals, are consuming began its journey into the deep actually in the Antarctic and it takes several hundred

years for it to kind of flow and get there. And that flow is getting weaker as a result of climate change. Yes, although does that mean that climate change is going to affect them in 300 years' time? It does. Yes, indeed. And that change is already on its way from changes that we've made in the atmosphere. So we already know that overall globally, the deep ocean will end up with about 10% less oxygen than it had in pre-industrial times. Now, it's very patchy in different bits will be affected more than some others, but overall globally, it's on track for 10% less than it had already. It's going to change the distributions of species around the world. Some can tolerate that, some can't. Their distributions are going to shift. And that's a change that's already

baked in. That's already happened. It's on its way to the deep ocean. It just hasn't reached the deepest places yet. Heather, it strikes me that when you're looking at something like the trenches, it involves a lot of different skills. It involves geologists, it involves engineers, it involves biologists, all sorts of people. How do they work together? Do they understand what the other is doing? Very much so. I think I can speak on all of us, you know, like I think the most rewarding expeditions have been the cross, multidisciplinary ones. And each discipline, you know, thinks a little bit differently, you know, the engineers to the geologists, to the physical oceanographers, to the biogeochemists. And I think that fusion and that sort of spark between the different

disciplines and making, you know, hearing about their research questions and their concerns or their technological challenges or what aspects they're trying to overcome. And then you can sort of, oh, well, actually, you know, we do it this way. Or, you know, you can take and learn from each other. But I mean, you know, I've worked, you know, over 20 years now with all these different disciplines and learn so much. And I think in order to undertake successful research, you need to be able to work together with everyone in these environments. And it certainly I've learned a lot in terms of, you know, I'm a geologist, not an engineer, in terms of the challenges in terms of how you build vehicles to put down to these sort of depths and things, you know, working with Alan, for example, as an engineer. You know, it's fascinating and it's allowed me to think better and more strategically and more creatively about how to sort of address geological questions, you know, like how can we get physical samples and cores from these deep areas

without using a big drill ship like the Japanese vehicle, Chikyu, you know, trying to think a little bit more out of the box. But I think also in terms of the big discoveries, I think if you look back at how those expeditions and how the people are, on board of work together, that's helped contribute to some of these big discoveries that we're making in the deep sea now as well. It struck me in this discussion how remarkable the research into biology has been. John, I've got a question for you. How do you study these animals when presumably, if you bring them up to the surface, they're not going to survive, are they? They don't survive, no. They don't explode, okay, because of the precious thing that we talked about in,

in reverse, okay? There's nothing in them to expand as they come up, if it's solid tissue and liquid body fluids. But we can learn a lot from the specimens that we do get, of course. We can look at the adaptations they've got. We can look at what molecules are in their cells and so on. These days, though, we're also able to preserve animals actually at the seafloor, which is really useful. So, for example, you can collect a specimen and you can process it in a way that its tissues are preserved in something that allows you to see

what genes are actually switched on at the moment that you encountered it. So that, you know, otherwise, we can do that with specimens we bring up, but of course they'll have gone through a lot of changes on the way up. But actually being able to preserve things in situ is giving us really big insights in what we call genomics

and transcriptomics, seeing what genes are actually being switched on in that organism in its environment to understand how it's adapted to the conditions down there. Historically, Alan, people have believed that this is an area of giant monsters and all sorts of mysterious creatures.

Do you encounter that sort of attitude today despite the fact that we now have a much better idea of what's down there and they're not giant monsters? Yes, all the time. It's one of the most common questions you get is about questions about Megalodon and stuff like that And, you know, I think when you start looking into the energy in these systems, it could never, ever support a large animal, especially not at that kind of size.

But even bigger than a shoe is quite difficult to maintain of those kind of depth. So it's just all to do with education, I think, in the way in which Deep Sea's portrayed in the media and things like that. I think we can probably do it a bit more responsibly and stop referring to monsters and creatures and stop making movies about it. But then, you know, little snailfish aren't going to make a Hollywood movie, right? So, you know, they don't even have any teeth. Well, they did make a Disney movie about a clownfish, so maybe the snailfish could come next. Yeah. Who knows?

I'm very interested in deep-sea vents and deep-sea mining. Is that something that you have to engage with, that debate about whether the minerals should be exploited in this way? I mean, I work primarily on deep-sea vents, which we don't get in subduction trenches in the same. the same way, these black smoker systems and so on. Yes, deep sea, that is one of the environments that's being targeted for a form of deep sea mining. There are others as well. People get very excited these days about the manganese nodules. That's a totally different environment, totally different set of ecological kind of challenges involved there. For deep sea vents, the active ones, which have these incredible colonies of species living around them,

we don't actually need to do any more research to say that mining active deep sea vents would risk extinction of species. And we've been very clear to that to the international regulators. And I hope when they do draw up some kind of code for this activity in the future, that'll be the top line for this environment is that active deep sea vents must be protected. And one final question. Is the Mariana trench less interesting now because it's pretty well known what's down there and it's not as active as the other trenches? Or will people still want to go down? Heather? I think as Alan hinted at, you know, just because it is the deepest, of course, you know,

there's still going to be a lot of interest and activity down there. But, I mean, for me, you know, the South Sandwich trench, the Tonga Trench, the Kermodeck trench, are much more interesting from a geological perspective in terms of the activity going on there. We're managing to document sort of volcanic, pyroclastic density currents at, you know, and the rocks that have been deposited by those features at 8,000 metres wash depth, which has never been done before. So we're starting to look at new processes.

We're getting little glimpsies as to volcanic processes at depth in these environments now that hadn't been noticed before. So there's still a lot to be learned from these environments. But I think certainly sort of widening and working elsewhere and engaging with other researchers as well. There's also another way to look at it, because the mariana's massive, right?

if the volume in the Mariana is about the same as the volume of the Himalaya, and the size of a submersible might, let's say, it's the size of a Land Rover. Yeah. So if you put a land rover on the Himalaya and said, look, how long is it going to take for you, to document everything on this thing? It's going to take you a while.

Right. So you could theoretically spend your entire life, just working on that thing. But again, within the bookends of it being, this is what happens in the Malianan trench. You can't necessarily make bigger statements about this is what happens in every trench. But it's still valid.

And the Mania Trench really is actually five different areas. there are subducting seamage which partition it. So from an animal that challenge of deep, for example, could not get to the top of Marianna Trench without having to decompress by thousands and thousands of metres. So technically it's five bins of really deep ones. So yeah, there's all sorts of interesting things to do. My thanks to John Copley, Heather Stewart and Alan Jameson.

And next week, it's the Roman arena and the role of gladiator fights in imperial politics. Thank you for listening. And the In Our Time podcast gets some extra time. time now with a few minutes of bonus material from Misha and his guests. So tell me, what did we miss out, John? I personally, I'm really fascinated in kind of like the inner space race that took people to the bottom Marianna Trench for the first time and the context for that.

There were various private individuals who were designing these vehicles and engaged in this work and innovating and so on and then the French Navy wanted to get involved and then they had a bit of a bust up and eventually the US Navy got involved and bought up the technology. At a time when they were during the Cold War, this is around about 1960, when they were really flexing their muscles publicly in terms of capability in the ocean, they sent a submarine underneath the North Pole for the first time. They surfaced one at the North Pole. They had the first circumnavigation submerged by a nuclear submarine and they wanted to be the

people to get to the deepest point for the first time. So that whole story I think is a very interesting way. mirroring the space story. To some extent, the Russia, the Soviet Union really weren't involved in sending people. I mean, they were sampling deep trenches in the late 1950s and looking at life down there, but they weren't looking at these kinds of demonstrations of capability in the same way. What did we miss out? I think the evolution of the Pacific Ocean as a whole is really interesting.

So if we go back 200, 300 million years, We had a supercontinent called Pangaea, and it was surrounded by a super ocean called Pantalassa. And basically Pacific is the last remnant of that ancient ocean. And that's why it's so much older than the Indian and Atlantic. So they opened 200 million years ago as this supercontinent Pangaea started to break apart. That's when the Atlantic and the Indian Ocean is starting to open. But what's really cool is that in the Northwest Pacific,

actually just near the Mariana is where they sampled the oldest oceanic crust in 1989 and it was drilled by a big international collaboration called the Ocean Drilling Program and that was 100, it proved rocks that are Jurassic and age 170 million years old and that is just fantastic

and I love the fact that the Pacific Ocean is this old ocean made of old geological rocks the oldest oceanic rocks that we have on our planet. And that's why the Pacific Ocean technically is contracting as it's getting consumed rather than the Atlantic and Indian that are still opening and widening at this time. So that's still the breakup of Pangaea? Yes, yeah.

And I love that. I love that the geological timescale is still sort of trundling on and it's just this conveyor belt of motion. So if we think about plate tectonics and the earth being made up with these jigsaw pieces, he's all sort of moving relative to each other and some are sliding past one another. That's a strike slip, sort of margin

or one's being consumed by another. That's your convergent. That's your subduction areas. And other ones are sort of where we get new crust being formed. And I just love that conveyor belt of evolution. John. The thing that surprises me as a biologist, though, when I hear about this geological history,

is that nevertheless, even though the Pacific is the oldest bit of ocean crust we've got, it's still really, to me, very young. you know, compared to three and a half billion-year rocks on land in some places. Yeah, well, 4.6 billion year. Central Canada, and even the northwest of Scotland, that's some of the oldest rocks on our planet is 4.3 million billion. But I think it shows how dynamic the ocean is.

Yes. You know, that's the thing. It's much more dynamic than the land. Yeah. But, Alan, anything you feel we've missed out? I've got a funny story about a party. Go on then. So, yeah, so the challenge of deep was not discreet.

discovered in 1875. It was discovered in 1952, right? By Challenger 2, right? So I read this book once. It was called a hydrographer's tale, and it's by a guy called Steve Ritchie, who ended up rear Admiral Steve Ritchie. He was the highest rank in hydrographer on the Royal Navy. And he had done the soundings for the D-Day landings. He ended up

on Challenger 2, and he sounded what is now Challenger Deep, the 10,000. And I remember talking to my boss, I used to work in Aberdeen for many years. I said to my boss, like, this guy, this is the guy discovered Challenger Deep. My boss said, yeah, he lives just up the road. I was like, you're kidding me. So I ended up at his 93rd birthday party.

And he lived in a town called Coliston and his family had been there for 200 years. And we turned up thinking there's going to be this frail old man in this cottage. I really hope there's rum at that party. Admiral's story. It was wearing some like African poncho in his house is all like oil on canvas drawings

of some harbour in Borneo somewhere. It was brilliant. Unfortunately he died a couple of years later but it was great to just, you know, it's like I've actually met and went to the birthday party of the guy. Discovered John's Day. Let me get this straight. That Challenger Deep was only really identified by his It's murky because someone gets a deep siding

which says there's something big there but then refining just exactly where the deepest point is takes a little time. So Challenger Jeep is a feature on a map turns up in 1877 but it's not, you know, that's before there was a marionna trench or whatever and it's just, and that's one measurement

and they've just drawn a kind of a circle around by the way, did the challenger, the original challenger, did they have to have rope going down five kilometres or something? They did, I wrote it down actually Hang on. The piano wire. Yeah.

It was a phenomenal. They covered 70,000 nautical miles, but they had 144 miles of Italian hemp for the soundings that they were doing. And quite often they had a bucket on the end of that rope so they could take like a little sample and that's of the sediment that was down there. But I mean, imagine having track of all of that wire.

And it wasn't actually the absolute cutting edge technology at the time. So Lord Kelvin, the absolute polymath genius, 1872, he'd invented a wire sounding machine using piano wire to measure the depth. So what they do is they lower a weighted line and they kind of look at the rate at which the line is paying out. And when it slows down, they assume the bottom of it is now touching the seabed. And it's, you know... In really deep water. In really deep water, yeah. Ocean currents can take it.

And so anyway, that's why a lot of the early measurements are way off. for things. Lord Kelvin's piano wire machine is much more reliable. Now he sent one to the HMS Challenger but they couldn't get it to work properly it was still a prototype and so they just shelved it and they went with tried and tested hemp. They still had, was it, 12 and a half miles

of piano wire with them as well? You know, it's just... And actually that's something that, because of the popularity of upright pianos amongst the middle classes of the 19th century led to mass production of piano wire which meant it was available in these huge lengths for ocean soundings.

Yeah. What do we use for ocean sounding today? Acoustics. Sound. Yeah. But very, very accurate, right? Yeah. Yeah.

So, I mean, yeah, we know that, you know, Challenger deep, for example, is 10,925 meters. Plus or minus six. Yeah, plus or minus six. Error margin, you know. And it's, you know, that's using sort of a sound to sort of, it goes from the ship down to the seafloor, bounces off the seafloor and comes back up.

What's interesting, it was the meteor, um, the meteor, T.R in 1926 used sound to measure water depth for scientific purposes. It had been used by the military pre-1926, but the first use for scientific purposes was actually in the South Atlantic, in the South Sandwich Trench. And it was an expedition and they measured, we went back and surveyed it in 2019, well, yeah. And we were within one metre of what they recorded in 1926. It was Germans that had been out on RV Meteor and it was you know that way that's just

it was almost 100 years later. There is a stopgrap in here. So it's meteor deep. In between the ropes and the acoustics there was a thing called bomb sounding which was brilliant. So you'd stand on the back of the boat you like a stick of dynamite. You throw it off so it blows up on the surface and there's a kid in the hull who pushes a stopwatch when the

band goes off and then pushes the stock watch when you hear the echo. They're also trimming the length of the stock on the dynamite as well. The echo coming back from... You basically listen to the bang. So you come back, you know that speed goes around 1,500 metres per second. So you divide the time it takes between the bang and the echo by 1500 meters per second.

That gives you the depth. And so some of the... There's a guy called Bob Fisher and Kuhlenberg and these guys. They would sort of draw it based on these things. And there's hand drawn on a Philippine trench. I think we went there and tell you what, it's not bad. It's not bad, given they're just lobbing dynamite off the back of the boat. There's a scientific paper with Bob Fisher stood on the back deck with a...

basically, a case of TNT. Just like lighting it off a cigar and just lobbing it into the ocean. I hate to be writing the risk assessment for that trip. And then eventually when we get echo sounding, after bomb sounding, that was in part because of the Titanic. So there was a German inventor who, after Titanic, came up with a way, well, can we detect potential collision obstacles using sound looking ahead? And then people said, well, if we turn that vertically,

we can use that to measure ocean depth. Got it. That's safer. I bet it is. Well, just a little bit. Yeah. I was also very interested, by the way, in the fact that the fibre optic cables are only at Challenger Deep. And I can just imagine the type of the endless covert activity that is going on in places like this. And it's not a little bit. It's everywhere. It's everywhere. And you don't want to get tangled up in it because you have no idea if it's a thousand meters long or 10,000 meters. But it's everywhere. We don't know if there's something on the end of it. So whenever you're going along there, you've got to keep your eye out. And as soon as it's cut the dive, just move.

We actually drew a map of it and tried to recommend an area to not take a tethered or an untethered vehicle because it's pretty bad. Why do you want to get rid of the fibre optic cable? Because presumably you can reuse it. Oh, there's lots of different reasons.

Some of it's obviously... I'm not sure I'm talking to who we think's doing it. Some of it's underwater cable, which is... Yeah, it's about getting live communication back to the surface. So there's ways in which you can do that by having a surface boy that gets winched below the surface so no one can see it. So you can, if you imagine you had a flotation device

with a beacon on it 100 metres under the surface and it's connected all the way at the bottom. Now you can listen to submarines coming out of Guam, which is, let's be honest, this is what's got something to do with that. But you don't want someone being able to steal your listening device. So you have a little winch that then comes up for an hour, beams all your information about it,

and then pulls it back down again. And so there are those in the area, we think. But to get that technology right and to get stuff down there, fibre optic is the way to go. And the vehicle John talked about, the fibro optic ROV, we had that out and it was terrible.

We happened to be there when it imploded. The whole thing imploded. It was just very experimental, but it was just a complete disaster. But all that fibre optic is gone there. It's all lying in the bottom of the sea again. So it's messy. It's really messy.

It's just like today, you know, we don't have anything apart from submersibles that go that depth. Technology is moving forward. and I think we need to move away from those sort of... Yeah, there was two solutions to it. One was super fine fibre optic, none of them was super heavy. Japanese went real big, heavy stuff,

and then the Americans went super thin, and both turned out to be the wrong. And then someone recently did a completely untethered one, and that got lost as well. So it's not easy, so we've gone somewhere in between, feels like the right thing to do. If it was easy, other people would... Yeah.

We wouldn't be doing it as a group, yeah. Yeah, yeah. I've come across quite a lot of fibre stuff in terms of drones as well now. Yes. that's the same stuff that was in that American it was torpedo wire and so it just falls out

so the faster you go the better it works if you stop and try to do anything it breaks which of course from a research perspective we're wanting to stop to pick up the samples of the communities and the rocks and things that are down there is it something that occurred to me is when you were talking about the life down there

and I think it's one of the sort of funnier thing is the snail fish eating the amphipods but of course amphipods eat soft things that have fallen down and are decaying So what do the snailfish do to stop the amphipods eating them from the inside out? They have an internal jaw. So they have two mouths. They have the big mouth at the front that is suck an animal in.

But if they just swallow it, the animal then just bore itself out of its stomach. So it has a second jaw inside its head that when it swallows, it just grinds the animal to make sure it's dead. Oh, my God. But what is really from a non-biologist sort of, you know, and that's what I was talking about when you know, you pick up things from lots of different disciplines so that, you know, if you come across. across something unusual or noteworthy that isn't from your own discipline, you know that it's important. But when I'm looking back at some of the video and watching the snailfish, so you see them sort of suck up the amphipod, but then as it's the second internal jaw is working, they sort of collapse and they have a little food coma on the sea floor as this is working, don't they? And you just see

them. Yeah, they're just sort of sat, sort of, you know, doing a beach, well, what my family call a beached whale impression after you've had too big a meal. They're just all sort of sat on the sea floor, we're going, oh, crikey. But really, at least it means I'm not going to get consumed by my dinner from the inside out. You know, it's just sort of funny things like that that keep you going. But I mean, I think as we're sort of exploring more and more of these environments and stuff, you know, the discoveries that we're making makes it all worthwhile. It makes the sort of trips away from family and friends.

But also the other thing that I failed to ask you about, which I should have done, was about what the implications of the research are for human health. because that was a fascinating aspect of it in terms of, I think it's to do with the enzymes and the protein folding. Is that right, John? Well, there are a lot of insights we can get from deep sea animals. I mean, I'm not so familiar with actual trench organisms, but it's something I keep an eye on.

And, you know, deep sea life can inspire us in two different ways, actually for material science. So I was co-author and description of a species called the Scalyfoot snail, and it's teaching us how to make better solar panels because it can create tiny crystals of a metal mineral at room temperature and this is what people want to be able to do for solar panels and now people have been able to recreate this process in the lab with kind of off-the-shelf ingredients.

I also was involved in describing a species of deep-shree shrimp which has got tiny little bristles on it which have inspired a new nanomaterial that's fantastic for heat and sound insulation. So there's those sorts of things and then there's a lot on the biomedical side. one of the chaperone molecules that you get in a lot of deep sea life in laboratory studies

can help to rescue human proteins that get bent out shape which is involved in quite a few human diseases well look thank you all very much this has been absolutely fascinating really appreciate it ah Simon does anyone want tea or coffee or rum or something no I thank you the chances of finding a glass of rum in the BBC are actually less than zero Thank you very much.

Thank you. Brilliant, thank you. Thank you. In our time with Misha Gleney is produced by Simon Tillotson and it's a BBC Studios production. I'm Paul Kenyon and for Radio 4 and the History Podcast this is two Nottingham lads. When the invasion happened, it was completely hell on earth with the sounds.

The sad thing about war is people lose their empathy and their humanity. I want to know how two men from Nottingham ended up on opposite sides in the war in Ukraine, and what became of them after a chilling encounter in a prison in Danyetsk. Out of all the places in the world where I meet someone from Nottingham, it's in captivity on two sides of the conflict. It's a story about how and why you pick a side in a war that's not your own. You can listen to two Nottingham lads first on BBC Sounds.