The mysteries of the ocean floor

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Hello, delightful and curious-minded listeners.

Welcome to BBC Inside Science, the podcast, first broadcast on the 8th of May, 2025.

I'm Victoria Gill.

And today, we are diving into the unknown because scientists are calling for a new global effort to explore the deep ocean.

And it's VE Day.

As the celebrations and commemorations continue, we're taking a historical view of the unexpected relationship between science and war.

And Penny Sachet is here, managing editor of The New Scientist, podcast host, host, and astute science watcher, bringing us some of the top science stories that you might have missed.

Hello, Penny, what have you got for us?

Hi, yeah, I've got what all the cool ancient Greeks were listening to.

I'm looking forward to that.

Excellent.

So we have a little bit of a music interlude later on.

First, though, to the deep ocean.

Water covers more than 60% of our planet, and the ocean is the largest habitat on Earth, with wildly diverse environments, deep ocean trenches, undersea mountains, and deep reefs.

You might have heard that old cliché that we know more about the surface of the moon than we do about the deep sea.

But a study published just yesterday has revealed exactly how little we know about this deep, dark realm.

The research led by the rather cinematically named Ocean Discovery League worked out that 99.999% of the global deep seafloor remains unseen by human eyes.

I spoke to the lead author and deep sea explorer, Katie Bell.

I like that it's a league.

It sort of makes you sound like superheroes.

Well, that was the whole point when we came up with a name, the sort of bringing together lots of different people with different skills to be able to,

you know, figure out how we can accelerate deep sea exploration and research.

Let me get my number of zeros correct.

We have visualized 0.001%.

Is that correct?

You've got it.

Yeah, of the deep ocean.

How did you make that calculation?

Well, we did it in two different ways because when we initially did it, we didn't quite believe believe that it could be that small.

Initially, I found dive records from three different organizations in the United States that have been doing deep sea exploration and research for more than 10 years and took the average amount of time they've spent on the water, how much

we think that they would see at any one time, how fast they might travel along the seabed, and multiplied all that out and came up with an average amount of seabed seen per year.

And then said, okay, well, if there are 20 organizations around the world that operate these kinds of vehicles over the last 70 years, what would that number be?

And so we came up with about 0.001%.

And the number seemed so ridiculously small that we then decided that we needed to do a bit more research.

And we aggregated a database of over 43,000 deep-sea dives from institutions all over the world and

used

some of their actual track lines, so the actual distance traveled along the seafloor of different types of vehicles, so human-occupied vehicles and remotely operated vehicles, landers.

and tow cameras, and then applied what we knew about dives where we actually had that kind of track line data to the entire database and came up with a similar number.

So having done it, you know, in two independent ways and coming up with the same order of magnitude, we feel

pretty sure about this 0.001% being actually the sort of maximum amount that we've seen because we've accounted for the fact that we may not have gathered all of the dives and there may you know have been some observations that we don't yet have.

It is astonishingly small.

Why is it that we've seen so little of the deep sea floor?

Well, one of the primary reasons is that it's just so expensive to do deep sea exploration and research.

You know, you need millions of dollars to get a ship and

a vehicle that can do this kind of work.

And so, therefore, only the wealthiest countries have access to these kinds of tools.

We're at a really exciting place right now, I think.

So, you know, what we've documented is the history of deep sea exploration, or at least modern deep sea exploration for the past 70 or so years.

But now there are a lot of researchers and

engineers around the world who are working on lower cost, more accessible technologies so that you don't have to have these enormous research vessels to be able to get down there and look and collect samples on the deep sea floor.

So that is going to make it much easier for people, especially in countries that haven't had access to these kinds of tools, to be able to do research for themselves, which I think is very exciting.

I'm curious as well, this paper is coming out very close to David Attenborough's 99th birthday.

Yes, it was not played.

Really?

Yes, we just saw there was a premiere or something this week on his new film.

So no, it was a fortuitous accident.

Well I hope that'll shine a bit more of a light on just how much more there is to discover.

But Katie, thank you so much for joining us.

That was really interesting to talk to you.

Thank you, Victoria, for having me.

Dr.

Katie Croft Bell there, making the compelling case for exploring the deep.

And we'll come back to that very special 99th birthday as well a little bit later.

But we want to understand what we can learn from studying the environment and the life in the deep ocean.

So joining us now, we have Dr.

Anna Gabrook, who is a marine biologist who specialises in the deep sea at the University of Edinburgh.

Hi, Anna.

Hi, Vic.

Thank you very much for joining us.

It's a pleasure to have you.

And Penny Sasha is here too.

Now, Anna, when we called you, we wanted to chat about this research, and you were in your lab in the middle of scrutinising deep sea sponges.

That is correct.

That's what I've been doing this morning as well.

So, this particular data set comes from the Faroe Shetland Sponge Belt Nature Marine Protected Area.

So, that's an area of the Atlantic Ocean, sort of northwest of the Shetland Islands.

It has been designated as a marine protected area, particularly because it has those aggregations of deep-sea sponges, which are very simple organisms and vertebrates, deep-sea invertebrates, but they are very important because they provide critical habitats for other species and they also play a very important role in nutrient cycling.

And also, some of the sponge species are important for medical research.

There is a lot of kind of biomedical innovations that come from sponges.

Right.

And rather than just sort of grabbing what you can from the seafloor, why is it so important to you to see them?

For example, habitat mapping, predictive habitat mapping to understand where we can expect to see um certain species we need to have good baseline data and that's where it's really important to get some in-situ data from the seafloor and the first step is always just to map things and then when we have those baseline data we can start modeling it and do some predictions but it's really expensive it's really difficult we need you know these these incredibly engineered robots that can um that rovers and machines that can withstand these incredible pressures give me the elevator pitch for why that should be a priority and and that science and engineering should be done well i i'm sure sir david attenberg will do a better job at it than me but i think the simple message there is that you know health of the ocean is the health of the planet um the ocean is a giant melting pot which plays the absolutely crucial role in um climate regulation amongst other things and of course the deep sea habitat is the single largest continuous habitat in the ocean so it has a very important role in that in things like carbon sequestration carbon cycling biological pumps so connecting the sea floor and the pelagic ecosystems the water surface if we want to see a healthy ocean with healthy ecosystems with fish stocks we need to make sure that the deep sea ecosystems are healthy and we still know so little about them that we don't really understand how our activities impact them.

Penny.

I guess it's not that surprising that we haven't seen so much of the deep sea because it's so expensive and it's so hard.

But how is that changing with all of this commercial interest there now is in mining all of those sort of metallic nodules on the sea floor?

Is that, I mean, I guess it increases the urgency to understand this habitat.

Is it also sort of sending more funding into getting down there and seeing what's out there?

Does it sort of shape the research, send it off in a certain direction in some way?

There is certainly hope.

When there is an interest from an industry, there are often opportunities for collecting data, but then whether this data becomes accessible is another question.

And that's, I think, something that has been highlighted in the paper as well, that data management, especially for the deep sea, is a very big problem.

It's a fascinating realm, isn't it?

I get so captivated by the weirdness of life that exists in the deep.

You know, what keeps you as a biologist really fixated on the deep ocean?

What fascinates you?

I think part of it is just the, you know, the sheer excitement of the exploration and discovery element of that.

The idea that we get this unique chance to see the absolutely unexplored ecosystems, to discover new species, to discover new habitats is really, really exciting.

Do you have a favorite deep ocean creature?

Well, I am an invertebrate zoologist by training, which means that I specialize in different invertebrate organisms.

I

love the giant tube worms, which live on the hydrothermal vents.

and yeah there is one particular one that i haven't seen

but it is my big dream to visit it my dad is a marine biologist as well and he named a little part of the hydrothermal vent field um in the logachev area after measure's garden it's been described as one of the few locations of the calyptogena clumps that have bacteria living in their gills that have

ability to basically transform those toxic chemicals into energy, which is pretty exciting.

That is very exciting.

I hope you get to see it, Anna.

Thank you so much, Anna Gibrock.

Thank you for joining us.

Thank you.

It's been a pleasure.

Penny, do you have a favourite deep ocean creature?

I take a real sort of childish pleasure in the battle between the colossal squid and the sperm whales.

We know so little.

We know that they're fighting, but not much more than that.

Yeah, I have a soft spot for a few of the squids, the glass squid that live in the deep deep that are amazing, but the cockeyed squid I think is my favourite, purely because of the name, one massive eye that looks up for prey and one little eye that looks up.

Oh, wow, that sounds kind of cute.

Ugly cute.

Ugly.

Google image it.

I recommend it.

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You're listening to Inside Science with me, Victoria Gill.

Now, it is, of course, VE Day, and there's been a series of special events to commemorate the 80th anniversary of the moment the Second World War ended in Europe.

And in terms of science, we might think of war as a time of innovation when countries look to scientists and engineers to invent our way out of conflict.

So, was that the case during World War II?

David Edgerton joins me now to shed some historical light on this.

He is Hans Rousing Professor of History of Science and Technology at King's College London.

Hi, David, welcome to the programme.

Hello.

Now, how significant was the role of scientific research in bringing the Second World War to an end?

You know, that's what we're at, the end of the war in Europe is what we're celebrating today.

How much did science play a role?

Well, I don't think you could ascribe too great a role

to scientific research in ending the war.

I mean, the greatest contribution, I suppose, was that of the Red Army, of the factories in the United States, and many, many other things besides.

Now, that's not to say that the nature of war hadn't changed, that new weapons hadn't been developed, but I think it's wrong to claim that scientific research, certainly that done in the war, had a decisive impact on its outcome.

And it's maybe suggested that the urgency of technological development, the extra resources put into that, can push innovation at times of war.

Is that the case?

Well, I mean, certainly all governments engaged in the war, nearly all of them, put more money into

research and development.

But typically, they were researching and developing established things like radar or aero engines or tanks or or guns or pharmaceuticals.

But the more money you put in, I mean, the faster you can develop and the faster that you can deploy.

But what government's trying to do was to generate better weapons.

So

the idea that war stimulated invention or innovation in general, which one often hears, is not, I think, the way to think about it.

I mean, war stimulated

warlike innovation, not innovation in general.

Penny.

Yeah, I wondered about that because uh if you are sort of tailoring your research for those kind of things that you really need during warfare what happens to blue sky science or the subjects that aren't directly related to war um did we see a whole load of things just getting put on hold for for however long well exactly i mean blue sky science i mean that's a modern modern term uh it's something that mostly happens in in universities what happened say to universities in the in the uk well they were converted essentially into teaching only institutions in the united states universities started doing a lot of contract research for the military.

So yes, that blue sky research really ceases to be done.

And were there major advances during the Second World War that can be ascribed to how the priorities were being pushed into what areas?

So any particular innovations or developments that were sort of because it was a time of war?

Well, there's very fast development of radar, so lots of different kinds of radar are developed.

Very small radars that set off shells in the case of the proximity fuse.

There are new kinds of tank ammunition.

There are much more powerful aero engines that start to be used.

There's a whole lot of things that are developed at speed around the world.

Jet engines would be another example of something developed initially before the war that are deployed towards the end of the war.

And the politics and the politicians, you know, how much were their priorities shaping what research was done?

I understand Winston Churchill was quite pro science and tech that you know how much was the the priorities that were being funded at the time the drive of british politicians well i mean generally speaking it's it's the military that are driving innovation and for for for war as as as you'd expect but winston churchill is a particularly interesting case i mean a former soldier he is very interested in warlike innovation

and he has as his personal assistant and advisor on not just on science but on all sorts of things Frederick Lindemann, who's who was professor of physics in Oxford.

And Churchill himself was extraordinarily keen on particular means of war.

He promoted rockets very intensively.

They turned out to be not a good investment, but he pushed them very, very hard.

He was very interested in,

well, in fact, he invented a gigantic sort of mechanical mole that was meant to cross trenches in northern Europe in 1940.

It was rather overtaken by events.

And again, a lot of money went into that, which was essentially wasted.

And many in the academic community, including conservatives, thought that both Lindemann and Churchill were chasing after kind of silly inventions and overestimating their likely impact and didn't have perhaps a high opinion of Churchill and Lindemann as perhaps

we do today.

You say a complicated time.

The other thing people might think about in terms of science of war is science sort of being usurped for unethical means, you know, perhaps by the Nazis, some sort of horrific acts that were carried out masquerading as medical research.

You know, how much is the legacy of that

can we talk about today in terms of trust in science or in terms of its legacy for scientific research?

Yeah, I mean there was certainly a strong sense that the Nazis had taken over and damaged science.

But it's very important to remember that many scientists, especially the more politicized scientists, thought the application of science to war by everybody was a corruption of science.

And they looked back to the First World War to chemical weapons.

And in relation to the Second World War, many thought that the use of physical research to develop atomic bombs was itself unethical.

So it wasn't just the Nazis that were tarred with this brush.

There certainly was a concern amongst many people that science was now being used by states for purposes which were not necessarily good ones.

And it's

a complicated time and a complicated relationship.

How much can we quantify to what extent science was affected by war and the legacy of World War II on science today?

Well, I think it would be very difficult to quantify it, but I think the point to make is that war and indeed the military changed science and continued to be influential in it.

I mean, after the Second World War, huge investments continued in military aircraft, in atomic weapons, in military radar.

That was associated also with civilian developments in those sorts of areas, but the military remained hugely, hugely important in scientific research on a very permanent basis.

It's fascinating.

Thank you so much, David Edgerton.

My pleasure.

And David is also the author of the book Britain's War Machine.

And Penny Sasha is in the studio with me.

Penny, you have been looking through this week's science stories, haven't you?

You promised me some Greco-Roman music, but where are we starting?

Yeah, let's save the fun bit to the end.

Sounds good.

Should we start with then foresight?

I don't know if you saw this large language model that's been trained on a lot of patient data in the UK.

Yes, this was somewhat surprising to me.

I was surprised too.

What has happened here?

So the development now is that this is essentially an AI, an LLM, that now has been trained on the health data of 57 million people.

So that's essentially basically everyone in England.

And that's data things like appointments that people have had, different departments and hospitals and that's the kind of scope of the data.

Before we go into the ethics of access to that data, to what end?

So the idea is if you train an AI on it, can you then use that to make predictions?

And so there's not that much detail available yet about what they're using it for.

But so far it seems to be approved for kind of quite tightly specific COVID research.

I saw one suggestion was, say, could you look at the impact of delayed or missed appointments because of the pandemic?

What impact might that have had on like heart disease outcomes or something like that?

Who has made this large language model?

How have they got access to all of this medical data?

There are scientists at UCL involved, obviously, the NHS is involved, and there have been various reassurances.

So, this AI can only be used in what's known as a secure data environment.

It's not something that everyone's got on their laptop and taking home.

And also, they de-identified the data, which to a degree is reassuring because your name shouldn't be next to all of your health problems in this AI.

However, it has got some people worried because for data to be really informative for training in AI, it actually has to be quite rich.

There has to be lots of facets to it so that an AI can learn all about what people are actually like.

And so if it's that rich, then I don't think it's really possible to rule out that someone couldn't go in and work out who's who or who some people are anyway.

So we'll be keeping a close eye on this one because we'll probably hear more about this as they kind of...

Well, I hope so.

I'm really interested to see what they do with it and how predictive it really is because obviously there's a lot spoken about how useful ai is but it remains to be seen how useful it really can be yeah yeah um so um what next we're going back to to covert aren't we we had some more news on that this week yeah so um yesterday we had a new genomic analysis of coronaviruses in bats and other mammals so not all coronaviruses this kind of a smaller subset that includes the virus that caused covid but also a very closely related virus that caused SARS 20 years earlier.

So this is using genomics, kind of the blueprint of the virus back in a host species to figure out where it came from.

Yeah, so essentially, what they're doing is they're looking at the genetic material of this kind of small little group of viruses.

And in theory, usually with genomics, you can see how different things are and use that to build a family tree, what's related to who, and where has it gone, and how did that happen.

And for a long time, that's been really quite difficult between SARS and COVID because they're so closely related, they often swap whole bits of their genome, and it's then it sort of makes it hard to draw out that tree.

So, this analysis basically focused on bits that don't get swapped, and it paints a sort of a picture that actually isn't that surprising, but it is quite interesting.

And it's how did these viruses that were in bats end up emerging into people?

And there's a sort of geographical conundrum that's addressed there because it does look like these viruses were circulating for years in western China, both of them, SARS and COVID, before they then crossed over into people very far away.

So, it is China, but Wuhan is a long way from western China.

So, there's been this question about: okay, well, all direct evidence suggests it came from animals, but how on earth did it travel that far?

And so, this new study sort of paints the picture that although this COVID virus was circulating five to seven years before it emerged in people, that's not actually enough to travel that distance.

And so, what seems to have happened is bats gave it to some other mammals, other mammals brought it across, and that was incredibly accelerated by probably the wildlife trade.

It just wouldn't have happened on its own at that speed.

So, the kind of evolution of this genome ties in with the wildlife trades and that kind of natural emergence, but via a wildlife.

Yes, yeah.

So, it's not that the wildlife trade made the virus evolve a certain way, it's that by looking at the virus and tracing its tree, we can see that it was over there, but it got over here.

Does that give us more biological evidence for the natural emergence and zoonotic?

Yes, exactly.

And so, this study does show that's also what happened with SARS we basically already thought that SARS was 20 years ago and the sort of accepted scientific opinion was this is what happened it got transported to people because of the wildlife trade and so researchers have been warning for decades now about zoonotic spillover however there are still people who really sort of want to believe that it this lab leak hypothesis which I think it's worth saying there's still no direct evidence at all.

All the direct evidence and the weight of scientific evidence is pointing to zoonotic below it coming from animals.

But I think what makes it really topical at the moment is, of course, that a few weeks ago, the Trump administration replaced some of their key COVID websites with this sort of statement that it was actually caused by a lab leak.

So it's rumbling on.

It is indeed, but it's the scientific evidence that we're interested in in this programme.

Now, I have a clip that I've been asked to play before you give us your last nugget of science news today.

So here goes.

Sounds not dissimilar to something I hear in my yoga class, but what was that?

What are we listening to?

So, that is a synthesized

idea of what ancient Greek music sounded like.

And so, this is a really interesting paper, quite complicated.

It gets deep into maths as well as classics and music, trying to work out how did the ancients tune their instruments.

Oh, right.

And so, one of the instruments, which I think is the one we had there, that they're looking at, is the lyre.

So, that's a sort of seven-string harp.

It never occurred to me that we knew the kind of music that the ancients were listening to, but we do actually have snatches of compositions and some notation, and certain instruments that have survived.

So, this one researcher has done this big analysis trying to work out, well, how did they tune the instruments, which is a fun thing to try and get to the bottom of.

The thing that sort of stood out there, and I think you could hear, is it kind of goes a bit funny and then comes back again, it's kind of moving in and out, which is quite modern, quite interesting.

And what the researcher here is theorising is that the ancient Greeks and Romans, particularly for instruments like the lyre, where you basically just tune the strings and then you just pluck them, you don't get much variation in how you play them.

What they really valued, the Greeks and Romans, was having these perfect pure tones between each of their notes,

which you'd think we value today, but actually we fudge it today.

There's a sort of mathematical quirk to music that if you keep moving around one whole tone at a time you can end up not in the same place that you started.

Things can sort of drift a little bit in and out of tune.

So if you think about a modern piano there's actually a bit of fudging.

You don't have quite so beautiful intervals between each note to make sure that you don't drift out of key.

And so the Greeks and Romans they love symmetry so they stuck with it with the lyre and instead what this paper suggests is that people who compose music for the lyre had to sort of live with this constraint that it would sort of fall out of tune and design their music around it so that everything is sort of technically perfectly in harmony all the time, but sometimes sounds a bit weird and then comes back again.

How fascinating.

Well, Penny Sasha, thank you so much for being on the programme.

It's been lovely to have you.

Do come back.

I will, my pleasure.

Thank you.

And I should say that that music clip was generated by Professor Dan C.

Batu.

Now, though, as we mentioned earlier, the film Ocean with Sir David Attenborough is is released in cinemas across the country today to tie in with Sir David's 99th birthday.

Now I grew up watching documentaries where Sir David in his inimitable, gentle and deeply insightful style shared his fascination with the natural world.

That inspired mine and many millions of others too.

So Inside Science producer Jonathan Blackwell has this David Attenborough audio time capsule to end the programme.

Happy birthday, Sir David.

I couldn't think of anyone better to give the last word to.

Enjoy.

It looked enormous, and from its size and markings, I was quite sure that it was a python, and therefore non-poisonous, which was something of a relief.

It's important to grab his tail as soon as you grab his head, otherwise he'll wrap his great coils round you and give you a very nasty squeeze.

After an hour, I found on the forest floor the rinds and cores of durian fruit.

The way in which it had been chewed showed that it had been eaten by an orangutan.

One must have been here early this morning.

A few minutes later, we heard a crashing in the branches ahead, and there, only a few yards away, we spotted a great furdy red form swaying in the trees.

Light has once more asserted its power.

The hour of the bat, the owl, the dormouse has passed.

The time of the day animals has returned.

But half of life is darkness.

The half we seldom see.

If children don't grow up knowing about nature and appreciating it, they will not understand it.

And if they don't understand it, they won't protect it.

And if they don't protect it, who will?

We are at a unique stage in our history.

Never before have we had such an awareness of what we are doing to the planet.

And never before

have we had the power to do something about that.

You have been listening to BBC Inside Science with me, Victoria Gill.

The producers were Dan Welsh, Claire Salisbury and Jonathan Blackwell.

Technical production was by Gavin Wong and Phil Lander.

And the show was made in Cardiff by BBC Wales and West.

Until next week, thank you for listening and bye-bye.

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