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TRANSCRIPT
Michel André: The perception of sound is the only one that we share, all living creatures on Earth – plant, animal, aquatic, or terrestrial.
Michel André has spent decades listening intently to the cryptic sounds coming from the world around us.
He works in bioacoustics – or what he calls "the science of the sound of life," using special microphones to capture the haunting calls of humpback whales swimming through the frigid waters off Antarctica...
And the eerie trills of leopard seals as they glide by...
Michel André: If we study this sound we have a unique way to understand the status of health of the planet.
Human activity has seriously altered life on Earth, impacting an estimated two-thirds of marine environments and around 75 percent of land ecosystems.
If we want to curb this loss, Michel and other researchers say it’s crucial that we use our sense of sound to understand what’s really going on.
Michel André: And this is what drives bioacoustics. It's really to understand everything that is behind sounds. And for us, it is maybe difficult to understand because we lost, maybe not interest, but at least the capacity that we had in the past to listen to the living world.
The one downside of bioacoustics, though, is that it’s a slow process. Michel, who heads the Laboratory of Applied Bioacoustics at the Technical University of Barcelona, can attest to the painstaking labor involved.
But consider this – a few years ago, Michel and his team were given access to a huge databank of underwater audio recordings for their whale research.
The recordings were from stations that monitor nuclear activity around the world and they run 24/7. And even though they were handed 10 years’ worth of data, it only took them…
Michel André: … 22 days. So, we analyzed the six centuries of continuous data in 22 days.
And that’s because they were using artificial intelligence. Which allowed them to go through what Michel said amounted to six hundred years’ worth of data, or in easier terms you could say, 5.2 million hours of audio recordings. In less than a month.
In this episode, we’re going to take a closer look at how bioacoustics could curb biodiversity loss and why Michel André says turbocharging it with the help of artificial intelligence could be "fundamental for the survival of all creatures on Earth."
We’re also going to include a behind the scenes chat about the research that went into this episode, so be sure to listen to the end.
This is Living Planet. I’m Kathleen Schuster.
The all but untouched environment of Antarctica has been compared to a natural laboratory with rich biodiversity that has evolved and adapted to extreme conditions. This makes it a prime spot for bioacoustics research, too.
Especially considering warmer currents and air are melting the ice at a rate of 135 billion tons a year.
Michel André’s research has expanded significantly over the past decade or so from his lab in Barcelona, to building a foundation in 2014 called the Sense of Silence.
It’s thanks to that foundation that he now has 12 yellow buoys bobbing off the shores of Antarctica. He’s hoping to capture a soundscape that has been inaccessible … up until now.
Michel André: During wintertime, of course, there is no boat, no one going there. So, we don't have any data or what is going on underneath the ice.
And this is something that is vital for the future, because once the ice melts, then we will have to have access to this data to be able to set this ecological corridor to protect biodiversity.
There’s a small box that dangles from the bottom of each buoy. The box is not much bigger than the length of a smartphone.
As it floats below the surface of the water, its thumb-sized hydrophone (a microphone adapted to water) records the mysterious soundscape within a 100-square-kilometer radius, or about 40 square miles.
And Michel’s listening for a number of things – like what does a healthy ecosystem sound like? Or whether he can hear intruders?
Michel André: Now that these temperatures are getting warmer, some species who could not access this water because they were too cold, they are slowly going there because they want to feed there and so they are entering in competition with the species, and then through the soundscape, we can analyze different soundscape and detect the species…
The microphones also capture the sounds of ice packs as they slide over each other…
This research is still in the early stages, and what Michel’s team needs are large volumes of data to train AI models with so they can get a full picture of Antarctica’s marine ecosystem. Luckily, they’re building on a foundation of about 10 years’ worth of sporadic data recorded during various expeditions as weather allowed.
But now the clock is ticking to monitor for longer stretches of time… and not just because of a warming climate. Humans are encroaching more and more on Antarctica’s fragile ecosystem.
"Sustainable cruises," for example, are noisy even when their engines are turned off…
Michel André: When you are on board of one of these cruise ships and they take you to this wonderful place, you are in this area where you are alone in the world and they tell you that you cannot stay for too long because you don't want to interrupt and you don't want to be too invasive.
So, you only stay for a few hours. And when you leave you really think that you have not made too much of an impact in the area.
But unfortunately, if you go on the deck and you look at the plotter, which is the map where all the different activities are around, you can see that there are 100, and I counted them, of this cruise ship waiting online to do exactly what you are doing.
More than 100,000 tourists have been visiting Antarctica each year post-pandemic.
That’s more than double the rate in the years leading up to 2020.
But why invest all of these resources just to hear odd noises, and maybe, noise pollution?
Can these sounds really tell researchers something new that would lead to better protection of biodiversity?
The short answer is yes, and early in his career, Michel found out just how powerful a tool bioacoustics can be when it comes to helping humans and other species coexist better.
In the early 90s, when Michel was working on his PhD in bioacoustics, there had been a series of collisions between sperm whales and high-speed ferries in the Canary Islands, in one case killing a passenger and a whale. So, a local company put some money into finding out why this was happening.
Michel André: And we then needed to understand better the distribution behavior of this population of sperm whales. And for some reason, that we understood a little bit later, they were right in the middle of the heaviest shipping route because this is where they were finding the food.
As it turns out, the shipping route was teeming with squid. And sperm whales eat one ton of squid per day.
So, it was no wonder that the 350 sperm whales living there had an interest in staying put.
The research got going, and what was puzzling was why the sperm whales weren’t moving out of the way of the boats.
Michel André: So the sperm is the largest of the tooth whales. He's also the most ancient whale on Earth. He's been on this planet for 35 millions of years.
And he has developed his brain, which is the largest brain that the Earth has ever seen.
It has developed it around sound production and sound analysis.
A little refresher on whales.
Whales are divided between what are known as baleen whales – like humpback whales and blue whales – and "toothed whales," for example the sperm whale.
What makes toothed whales unique is, of course, their conical teeth they use to snag their prey. But also, and crucially, the fact that they "see" with sound. This is called echolocation. Or biosonar.
And sperm whales use echolocation to find their food.
This is what the sound they make to do that …
Michel André: And with this sound, they are able to detect a squid at 3 kilometer distance, a squid of 25 centimeter long.
They can communicate over 15 kilometers constantly. They can detect the prey, they breed, and they tell whatever story they want to tell. And this is not something that we have access to yet.
So, sperm whales are making these click sounds as they dive and swim in groups of 15, hunting for food.
Michel André: So, this sound that we hear is really the essence of a 35 million year of evolution around the perception of the environment in the ocean.
So, with one of these click, and the series of click (starts snapping his fingers) when we hear one whale that does this, is one. If we have two, we would have this. And then we heard this series of maybe 15 members of the same pod.
So, these clicks, these sounds, is really the history of these most ancient whales on Earth.
So why were these highly communicative whales having so much trouble avoiding the shipping traffic? If they could hear each other, surely they could hear a boat?
Michel says the noise pollution caused by the ferries and other shipping traffic created a kind of “acoustic smog” that desensitized the whales to noise, making them less perceptive to oncoming danger. Two of the dead whales he examined even had severe damage to the inner ear.
So instead of trying to shoo the whales away with more noise, Michel’s team developed a system to help warn boat captains with passive acoustics, which means
Michel André: …that we listen and through the sound that we receive, we're able to triangulate and to detect the source and then to transmit this information to the captain. So he has information where the whales are on the route.
But a key piece of information was still missing in Michel’s research. What did all of those click patterns actually mean? Michel worked through months of data trying to figure out if it was just chaos or if the whales were communicating something else.
And then one day, as luck would have it, a cassette tape arrived in the mail.
It was from the wedding of a friend who had recently gotten married in Senegal.
The music on the cassette was of traditional Senegalese drumming.
And as he listened, an idea started to percolate – what if these drumming patterns were a clue?
Michel André: So I contacted my friend and I said, I would like to talk to these people. And after a few months, I managed to speak to one of these drum masters. And I came with my own cassette, but with sperm whale recordings.
And I asked him, "Well, listen, I have been able to extract these sequences, and I think there is some rhythmic component in these sequences. But you are an expert. And I said, please, can you listen to this cassette?"
It was only because Michel had been analyzing the data for months that he could identify the number of whales in the recording.
But he had a hunch the drum master would have a better trained ear, since he was accustomed to leading up to 40 drummers at once. And within seconds, he says the drum master knew how exactly many whales he was listening to…
Michel André: And then he pointed out something that I didn't know. He said, "Well, and this is the master." And I didn't know what he meant. And he explained what for him the master was. And in these tribes where you play drums…
The drum master was referring to the concept of having a lead drummer with his own special drumming pattern, and then each new drummer adds a distinct rhythm and pattern to the chorus of drums. Michel says it’s like a "rhythmic wheel."
And then suddenly it "clicked." Michel says, just like drumming, these sperm whale clicks had what he calls a "mathematical coherence"
– the beats and the interval of time separating them were key to communication.
Michel André: So this was sort of a confirmation that we could maybe unravel some communication patterns in underwater species if we would find some help with people who occasionally use a similar approach on land.
So it wasn’t just a problem that the whales had become desensitized to the noise. The fact that the noise was filling key intervals of silence in between their clicks was effectively severing their communication.
That sperm whale project resulted in what was hailed as the world’s first whale anti-collision system. It also opened Michel’s eyes, or rather ears, to the potential of using sound to unlock key information that could protect biodiversity. For example in Antarctica.
Fast forward to present day and Michel and his team have set up a worldwide network of 150 acoustic observatories that span several continents in collaboration with other researchers. Including in the Amazon.
This is another critical ecosystem for the health of the planet, which scientists warn is reaching a tipping point due to warming temperatures, drought, and an increase in logging and other human activities.
Michel André: In the Amazon, there is a constant mix of sound. There is not a single moment of the day where it is silence.
Which is equally alive during the day as at night…
Michel André: And during the night, you have all these different species, the frogs, the other birds, bats that they hunt and they look for their prey. And at the end of the night, when these night creatures go to sleep and the day species wake up and they are alive, I think that they know that they are alive because they start producing a lot of sounds as they tell, well, we made it again. We made it again. We are again alive one more day.
And thanks to their ability to use microphones both on land and in water, they’ve been able to help explain more about a complex food web in the Mamirauá Reserve.
What’s important to note is that the reserve lies between the Solimoes River and the Japura River, which are major tributary systems that feed into the Amazon. They’re also the driver behind crucial seasonal flooding that makes this reserve an important wetland.
It’s a region that’s suffered intense drought in recent years.
These forests need seeds from local fruit trees in order to regenerate. Michel’s team also has figured out something new related to the complex food web that’s key to this regeneration which starts with flooding.
Michel André: It could be flooded by 10 to 12 meters of water. And you have these trees that are submerged, but they are producing this fruit. All the animals have learned how to survive on these branches. So, they go up and they live for four months on branches...
So different species help distribute these seeds, including…
Fish and dolphins. Yes, those are underwater recordings of fish and dolphins…
And this phenomenon was already known. That is to say, local indigenous groups already knew the fruit attracted the fish. But by adding hydrophonic recordings, Michel’s team was able to capture previously inaccessible data.
This added to the evidence of how inextricably linked the health of the flood basin and the health of the fruit-eating fish are.
Maintaining a worldwide network is not a cheap undertaking, of course – and this too will play into other international endeavors to monitor the health of the planet.
Unlike a lot of research relying on government funding, or transnational funding, like in the EU, Michel’s foundation has been able to secure private funding to the tune of several million euros per project.
Michel André: This network of that allows us to be ubiquitous. And so we have for the first time these other sense we can hear underwater and we have the sense that allows to be ubiquitous.
And so, again, this is capacity that this technology has given us, but this is also a big responsibility because now that we have access to all this data, we need to do something with this and not just being a witness of what is going on.