Why Scientists Are Bugging the Rainforest
October 18th, 2023
Via Wired, an article on how some scientists are using microphones and AI to automatically detect species by their chirps and croaks. This bioacoustics research could be critical for protecting ecosystems on a warming planet.
THERE’S MUCH, MUCH more to the rainforest than meets the eye. Even a highly trained observer can struggle to pick out individual animals in the tangle of plant life—animals that are often specifically adapted to hide from their enemies. Listen to the music of the forest, though, and you can get a decent idea of the species by their chirps, croaks, and grunts.
This is why scientists are increasingly bugging rainforests with microphones—a burgeoning field known as bioacoustics—and using AI to automatically parse sounds to identify species. Writing today in the journal Nature Communications, researchers describe a proof-of-concept project in the lowland Chocó region of Ecuador that shows the potential power of bioacoustics in conserving forests.
“Biodiversity monitoring has always been an expensive and difficult endeavor,” says entomologist and ecologist David Donoso of Ecuador’s National Polytechnic School, a coauthor of the paper. “The problem only worsens when you consider that good monitoring programs require many years of data to fully understand the dynamics of the system, and how specific problems affect these dynamics.”
The researchers picked over 40 sites across different landscape types, including active agricultural lands, plantations that had been abandoned for decades (and are recovering ecologically), and intact, old-growth forest. Below, you can see the instruments they deployed. At left is a microphone that recorded sound for two minutes every 15 minutes, so it didn’t drain its battery as quickly as recording 24/7. At right is a light trap for catching insects.
Once the team had these recordings, they tapped experts to identify birds and amphibians by their vocalizations, and used DNA from the light traps to identify nocturnal insects. They also used AI to identify the bird species by sound.
“We can say the scientific part is basically solved, so the AI models work,” says conservation ecologist Jörg Müller of the University of Würzburg in Germany, lead author of the paper. “It’s fine-scale, high-quality. And the nice thing is that you can store the data.” Several years of recordings will track how the forest ecosystem evolves over time, with species populations waxing or waning as new arrivals colonize the terrain, or as climate change affects which struggle or thrive in hotter, drier conditions.
In particular, scientists and conservationists are interested in learning about the composition of species that return to disturbed environments. In Ecuador, the agricultural land tends to attract birds from southern parts of South America with their natural open areas, which are similar to the Pampas grasslands. “So it could be that you have the same number of species in agriculture and all those forests, but totally different ones,” says Müller. “These habitats are not empty—they are full of birds—but not the original fauna from primeval forests.”
Researchers are also trying to track animals that are responding to a complex set of overlapping environmental stressors. Forest health used to primarily be a problem of deforestation. Now it is a far more complicated set of problems stemming from global climate change and land use. The Amazon, for instance, is threatened by both loggers and severe droughts.
One of the challenges of field observation is that it requires humans, who are very big mammals, to go traipsing through the forest, altering its normal bustle. But a microphone simply listens, a camera trap quietly watches for movement and snaps a picture, and a light trap silently attracts insects.
The study’s recordings picked up the ??purple-chested hummingbird, shown at top, and the extremely rare banded ground cuckoo, shown below. “This is the holy grail for ornithologists. Some ornithologists go to Ecuador for 30 years to see the bird and never see them,” says Müller. “And we report it with sound recorders and with camera traps. So it shows another advantage from these recorders: They do not disturb.”
Bioacoustics can’t fully replace ecology fieldwork, but can provide reams of data that would be extremely expensive to collect by merely sending scientists to remote areas for long stretches of time. With bioacoustic instruments, researchers must return to collect the data and swap batteries, but otherwise the technology can work uninterrupted for years. “Scaling sampling from 10, 100, [or] 1,000 sound recorders is much easier than training 10, 100, 1,000 people to go to a forest at the same time,” says Donoso.
“The need for this kind of rigorous assessment is enormous. It will never be cost-effective to have a kind of boots-on-the-ground approach,” agrees Eddie Game, the Nature Conservancy’s lead scientist and director of conservation for the Asia Pacific region, who wasn’t involved in the new research. “Even in relatively well-studied places it would be difficult, but certainly, in a tropical forest environment where that diversity of species is so extraordinary, it’s really difficult.”
A limitation, of course, is that while birds, insects, and frogs make a whole lot of noise, many species do not vocalize. A microphone would struggle to pick up the presence of a butterfly or a snake.
But no one’s suggesting that bioacoustics alone can quantify the biodiversity of a forest. As with the current experiment, bioacoustics work will be combined with the use of cameras, field researchers, and DNA collection. While this team harvested DNA directly from insects caught in light traps, others may collect environmental DNA, or eDNA, that animals leave behind in soil, air, and water. In June, for instance, a separate team showed how they used the filters at air quality stations to identify DNA that had been carried by the wind. In the future, ecologists might be able to sample forest soils to get an idea of what animals moved through the area. But while bioacoustics can continuously monitor for species, and eDNA can record clues about which ones crossed certain turf, only an ecologist can observe how those species might be interacting—who’s hunting who, for instance, or what kind of bird might be outcompeting another.
The bioacoustics data from the new study suggests that Ecuador’s forests can recover beautifully after small-scale pastures and cacao plantations are abandoned. For instance, the researchers found the banded ground cuckoo already in 30-year-old recovery forests. “Even our professional collaborators were surprised at how well the recovery forests were colonized by so-called old-growth species,” says Müller. “In comparison to Europe, they do it very quickly. So after, let’s say, 40, 50 years, it’s not fully an old-growth forest. But most of these very rare species can make use of this as a habitat, and thereby expand their population.”
This technology will also be helpful for monitoring forest recovery—to confirm, for example, that governments are actually restoring the areas they say they are. Satellite images can show that new trees have been planted, but they’re not proof of a healthy ecosystem or of biodiversity. “I think any ecologist would tell you that trees don’t make a forest ecosystem,” says Game. The cacophony of birds and insects and frogs—a thriving, complex mix of rainforest species—do.
“I think we’re just going to keep on learning so much more about what sound can tell us about the environment,” says Game, who compares bioacoustics to NASA’s Landsat program, which opened up satellite imagery to the scientific community and led to key research on climate change and wildfire damage. “It was radically transformational in the way we looked at the Earth. Sound has some similar potential to that,” he says.
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Read More »A Listening Network To Detect Nuclear Bomb Tests Found Blue Whales Instead
October 3rd, 2023
Via BBC, an article on how a listening built to detect nuclear bomb tests found blue whales instead:
Since the 1990s, a global network of sensors has listened for unauthorised nuclear detonations. But as Richard Fisher discovers, its creation has led to unanticipated upsides for science – such as identifying a previously unknown pod of pygmy blue whales.
For generations, the creatures swam through the ocean without crossing paths with any human beings. Some of them grew to 24m (80ft) long and weighed 90 tonnes. But if these enormous animals did encounter any boats, those meetings went unrecorded. Until recently, we didn’t even know they were there: a pod of pygmy blue whales in the Indian Ocean.
Their discovery in 2021 was all the more striking because of how they were found. We wouldn’t have come across them if it wasn’t for nuclear weapons.
What have atomic bombs got to do with a pod of whales? The answer lies in a global network of sensors, placed in some of the world’s most remote locations. Since the 1990s, its operators in a control room in Vienna, Austria have been listening for rogue nuclear tests. But as the years have passed, their network has also picked up many other sounds and rumblings throughout the ocean, ground and atmosphere – and that’s now proving a surprising boon to science.
The story of how the blue whales were found can be traced all the way back to the 1940s, when human beings discovered they could unlock the terrible power of the atom. After the US Trinity test and the bombing of Japan, decades of instability and fear followed, as nations raced to build their own arsenals and test ever-more powerful weapons.
After 50 years, many governments accepted that transparency was needed. If nuclear escalation was to be avoided, the world needed a way to know if any rogue nation or actor was conducting unauthorised tests. Only then could they trust one another.
So, in the 1990s, a number of nations signed and ratified the Comprehensive Nuclear-Test-Ban Treaty (CTBT), including the UK and many Western European nuclear powers. A few did not, including China, India and the US. While these hold-outs meant the treaty failed to come into force, the process did create a global norm against testing. And crucially, it also led to the establishment of a network capable of hearing, sniffing or sensing a nuclear detonation anywhere on Earth.
With sensors all over the world, the International Monitoring System – run by the CTBT Organisation in Vienna – has been operating ever since, growing to more than 300 facilities worldwide that can detect the sound, shockwaves and radioactive materials of nuclear explosions. This includes more than 120 seismic stations, 11 hydro-acoustic microphones in the oceans, 60 “infrasound” stations that pick up very low-frequency inaudible noise, and 80 detectors of radioactive particles or gases.
Many facilities can be found in quiet, relatively undisturbed locations. The US, for example, operates a station on Wake Island in the Pacific, one of the world’s most isolated atolls. Others can be found in Antarctica. However, a few are a little closer to civilisation, such as the seismic array in the village of Lajitas in Texas – 650km (400 miles) west of San Antonio – or the radionuclide station in Sacramento, California. (Here’s a map of all of them.)
Their widespread distribution means that if there’s a nuclear detonation somewhere on Earth, the operators of the Vienna control room will know, says Xyoli Perez Campos, director of the International Monitoring System division [IMS] of the CTBTO in Austria. “Wherever it happens, we have the technologies to cover it,” she says. “If there is an underground nuclear test, then we have the seismic technology to catch it. If the nuclear testing is underwater, then we have the hydro-acoustic stations. If testing happens in the atmosphere, then we have the infrasound. And the radionuclide stations allow us to distinguish if there was a nuclear component; that’s the smoking gun.”
Indeed, when North Korea conducted nuclear weapons tests in the 2000s and 2010s, various seismic sensors in the IMS picked up the waves from the blasts, and analysis of radioactive isotopes in the atmosphere confirmed it. The network has also sensed large non-nuclear blasts, like the enormous explosion in the port of Beirut in 2020, or the Hunga Tonga-Hunga Ha’apai volcanic eruption in January 2022.
The non-nuclear explosion in the port of Beirut in 2020 produced infrasound and seismic waves that could be detected from far away (Credit: Getty Images)
The non-nuclear explosion in the port of Beirut in 2020 produced infrasound and seismic waves that could be detected from far away (Credit: Getty Images)Recently, however, the IMS nuclear network has uncovered much more than big bangs. Over the past decade or so, as scientific access to the data has opened up, researchers have turned to the IMS to sense events that might otherwise go unnoticed. That includes the songs of whales, but also much more.
In June, hundreds of these scientists met at a conference in Vienna to share their findings. Researchers from Germany showed how the network’s hydro-acoustic sensors can monitor noise caused by shipping, a team from Japan presented findings about how they’d used the IMS to study submarine volcanic activity, and a Brazilian researcher spoke about the infrasound generated by the aurora borealis and aurora australis.
Others described efforts to detect the crash of avalanching glaciers from afar – building on previous research that deployed the network to keep tabs on calving icebergs in Antarctica.
The physicist Elizabeth Silber of Sandia National Laboratories in Albuquerque, New Mexico even demonstrated how the IMS’s detectors had picked up an “Earth-grazing fireball” – a meteoroid larger than 10cm (4in) that generated shockwaves as it struck the atmosphere on 22 September 2020.
As for the pygmy blue whales – a tropical subspecies of blue whale – they were discovered when researchers in Australia decided to listen a little closer to ocean sounds using the IMS’s hydro-acoustic network.
In 2021, bioacoustician Emmanuelle Leroy at the University of New South Wales, in Sydney, and colleagues analysed the songs of various whale populations in the central Indian ocean. A few years prior, a new song had been noticed, known as the “Chagos song”, or “Diego Garcia Downsweep”, named after the place it was detected: the Diego Garcia atoll in the Chagos archipelago.
At the time, five blue whale pods were known in the Indian Ocean, along with populations of Omura’s whales. But it wasn’t clear which group the Chagos song belonged to. Scientists know that each pod has strongly personalised calls, which means they can be sorted into “acoustic populations”, and this one did not match.
Leroy and colleagues realised that the IMS network would allow them to study the Chagos song over almost two decades, at various locations in the ocean, ranging from Sri Lanka to Western Australia. Their analysis concluded that the Chagos song must belong to an entirely new population of pygmy blue whales.
Finding this new pod was a significant piece of good news, not least because pygmy blue whales are so rare. In the 20th Century, blue whales were hunted close to extinction, from an estimated 239,000 in the 1920s to a low of around 360 in 1973.
When the architects of the IMS built their detection network, they did so hoping that the world would be a little safer. “What is really amazing for me is that these smart people decided that nuclear testing is a hazard for humanity, and not only did they write a treaty saying let’s stop it, but they came up with the technologies to monitor it. That is putting science and technology into good use for humanity,” says Perez Campos.
But even with that foresight, the network’s founders probably did not anticipate all of the IMS’s uses today. Its 300-plus stations have evolved into the ultimate planetary listening network. Right now, at remote locations all over the world, sensors are monitoring humanity and nature for sounds and rumbles that might otherwise go unnoticed – and that includes a family of whales singing a unique song. We might not be able to see this elusive pod, but they can nonetheless be heard.
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Read More »Can a Map of the Ocean Floor Be Crowdsourced?
October 3rd, 2023
Via BBC, an article on the potential for crowdsourcing to help map the ocean floor:
Tucked inside a federal government building in the American Rockies is the world’s best collection of seafloor maps. Occasionally a hard drive arrives in the mail, filled with new bathymetric – or seafloor – charts collected by survey vessels and research ships cruising the seas. The world’s largest public map of Earth’s oceans grows just a little bit more.
Cloaked in ocean, the seafloor has resisted human exploration for centuries. Folklore and myths told of it as the domain of terrifying sea monsters, gods, goddesses and lost underwater cities. Victorian-era sailors believed that there was no ocean floor at all, just an infinite abyss where the bodies of drowned sailors came to rest in watery purgatory.
Throughout the last century, modern scientific techniques and sonar have dispelled the stories and revealed a little understood seascape of crusted brine lakes, steaming volcanoes, and vast undulating underwater plains. We have only just begun to map, much less explore, this enormous subsea world.
One organisation wants to change this – and quickly. In 2023, Seabed 2030 announced that its latest map of the entire seafloor is nearly 25% complete. The data to make the world’s first publicly available map is stored at the International Hydrography Organization (IHO)’s Data Centre for Digital Bathymetry (DCDB) in a government building in Boulder, Colorado.
So far, the DCDB holds over 40 compressed terabytes of seafloor data. The biggest contributor is the US academic fleet: 17 research vessels owned by American universities which constantly circle the globe studying the deep ocean. Other contributors include the National Oceanic and Atmospheric Administration (NOAA) fleet, the Geological Survey of Ireland, and Germany’s Federal Maritime and Hydrographic Agency. The biggest users are scientists all over the world who rely on the data to conduct research.
Seabed 2030 has made extraordinary progress by asking countries and corporations to share maps with the DCDB. But unfortunately, the map is not growing quickly enough. Between 2016 and 2021, the map leapfrogged from 6% to 20%. Since then, the pace has slowed. In 2022, it reached just 23.3% complete; in 2023, 24.9%. The ocean mappers came up with a new plan: crowdsourcing.
By attaching a data logger to a boat’s echosounder, any vessel can build a simple map of the seafloor
“Crowdsourced bathymetry came about a few years ago when the IHO was saying: ‘At this rate, we’re never going to map the whole darn ocean; we need to start looking outside the box,'” says Jennifer Jencks, the director of the DCDB and the chair of a crowdsourced working group at the IHO.By attaching a data logger to a boat’s echosounder, any vessel can build a simple map of the seafloor. This is crucial in developing coastal and island nations. Tion Uriam, the head of the Hydrographic Unit at the Republic of Kiribati’s Ministry of Communications, Transport and Tourism Development, recently received two data loggers that he’s planning to install on local ferries. “It’s a win to be part of that initiative,” he says. “Just to put us on the map and raise our hands [to say] we want to be part of a global effort. Our contribution might be small – but it’s a contribution.”
Kiribati is a Pacific island nation of about 130,000 people spread across 33 coral atolls, only 20 of which are inhabited. British charts published in the 1950s and 1960s have been the most accurate maps to date; the United Kingdom and United States claimed various islands as protectorates or territories, mining them for phosphate or using them as whaling stations. Other British maps used are old and inaccurate; some date back to the late Victorian age or list depth measurements in fathoms, which most countries moved on from years go (the US only retired it in 2022).
That isn’t so unusual in the Pacific, according to marine geologist Kevin Mackay, who oversees Seabed 2030’s South and West Pacific Regional Centre at New Zealand’s National Institute of Water and Atmospheric Research (Niwa) in the capital Wellington. “The big problem in the Pacific is the relic of the colonial system. So, in the Pacific, who looks after the mapping? It’s the Americans through their territories, or the UK through their territories, or the French and their islands, even though they’re now officially independent.” Kiribati gained independence in 1979, but there’s been little progress on surveying since then. In 2020, the World Bank funded a $42m (£34.1m) project to improve maritime infrastructure in the outer islands. A portion of that will go toward seabed mapping.
As one of the least developed countries in the world, most i-Kiribati (the name for Kiribati’s inhabitants) live in the capital of South Tawara: a 17 sq km (6.5 sq mile) crescent-shaped atoll with a population density equal to Tokyo. More people are crowding into the capital in search of a modern life, while the rest live on remote islands where poverty and unemployment is high, amenities are poor and the long-term future uncertain because of rising sea levels and severe tropical storms.
The military or commercial value of nautical charts will always be a barrier to achieving complete coverage of the world map
Improved charts could boost trade, transit and tourism on the outer islands. They could help communities plan for tsunamis, storm surges and rising shorelines. Many islands lack basic tide gauges, and so visiting ships time their arrival for high tide. In his meetings with government ministers, Uriam tries to stress the economic benefits of improving nautical charts in Kiribati.However, there’s a roadblock when it comes to sharing maps with the DCDB archive back in Boulder. Around a third of the IHO’s 98 member states allow crowdsourcing inside territorial waters. However, the Pacific island nations of Kiribati, the Independent State of Samoa and the Cook Islands, which all recently received data loggers from Seabed 2030, are not among them. Until the governments give their blessing, the new crowdsourced maps will remain under wraps.
Despite Seabed 2030’s publicly stated scientific goal, the military or commercial value of nautical charts will always be a barrier to achieving complete coverage of the world map. “Sea charts, by their very nature, were destined to be removed from the academic realm and from general circulation,” wrote the map historian Lloyd Brown in his book The Story of Maps. “They were much more than an aid to navigation; they were in effect, the key to empire, the way to wealth.”
In a world where only a quarter of the seafloor is charted, there’s still an advantage in knowing more than your rivals. Niwa’s Mackay experienced this himself on a scientific-mapping expedition. He received a call from a military he chooses not to name and “they said ‘you need to destroy that data because there was military value in what you’re mapping, because it’s a place where submarines like to hide’,” he recalls. “Obviously, we ignore them because we’re [mapping] for science, we don’t care. But the military, they find lots of value in bathymetry that, as a scientist, we don’t even think about.”
For some nations, it’s also suspicious that the DCDB is based in the United States, which has the world’s most powerful military. “We have seen concerns as well, that the DCDB is hosted by the United States. Not everyone loves that,” says Jencks. She tries to assuage these concerns by stressing that the DCDB was endorsed by all IHO member states back when it was created in 1990.
In Kiribati, the challenges are less political, more practical, according to Uriam. His position as the head of the Hydrographic Unit only became permanent about a year ago. He used to work in the fisheries department and he knows just how hard is to share data across departments, let alone with outsiders. There’s also hurdles around storing data and hiring people with the right expertise to manage them. Another concern: foreign research vessels have mapped some of Kiribati’s territorial waters before and neglected to share data with the country’s government.
With just over six years left until the deadline, Seabed 2030 faces serious challenges in finishing the first public map of the seafloor. The staggering size of the ocean, the depths, the hostile offshore working environment where ocean mappers are constantly contending with wind, waves, and the corrosive effects of salt water. Then there’s the cost of mapping remote international waters where no country has a responsibility to map.
However, all these challenges seem small compared to the work of uniting countries behind a collective goal, particularly ones as diverse as the US and the Republic of Kiribati. The differences help explain why the goal of finishing a complete map of the seafloor may remain out of reach for many decades to come.
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