Diving Deep into Underwater Noise and Nature Listening Rx.
Plus some acoustic odds and ends for your enjoyment
Happy New Year! Welcome to the first substantive edition of the CLAMOR newsletter. This is a new adventure for me, so thanks for your patience as I work out the kinks in the months ahead. My focus will be on bringing you noise news from unsual places, along with some interesting listening. In this post, we’ll explore a worsening din beneath the waves, the sonic revival of coral reefs, and more evidence that protecing natural soundscapes is good for both nature and for us.
The Not-So-Silent Deep (and how a changing climate will make it even noisier)
In Jules Verne’s classic, Twenty Thousand Leagues Under the Sea, Captain Nemo takes the Nautilus deep to escape the violent seas of a hurricane.
“We had to seek repose at more than twenty-five fathoms [150 feet] submerged in the bowels of the deep,” recalled the novel’s protagonist, Professor Pierre Aronnax. “But there, what silence, what peace!”
The notion of a vast, silent peace beneath the waves is poetic, but false. Oceans are actually awash with sounds—from fish grunts to whale songs—that the inhabitants rely on to find food, avoid predators, and communicate where light to see by is often at a premium. This underwater world is also increasingly inundated with noise from a range of human sources from miltary sonar to natural resource exploration and extraction to more and more ships churning through the water with the freight and fuel of expanding global trade.
Global Seaborne Trade (Billions of Tons)
Rising Temperatures and Decibels
Meanwhile, a warming climate will make this underwater cacophony a lot worse in a couple ways highlighed by new research. First, melting polar ice will unlock some of the last vestiges of pristine, quiet ocean to vessel noise and other pollution. In 2024, the journal Nature published an analysis by Swedish and Norwegian scientists that raised an alarm about noise pollution from new luxury Arctic cruises, adding to a growing pile of studies on threats posed by newly opened shipping lanes and natural resource extraction in one of the planet’s few remaining quiet refuges. And as ship traffic grows, warmer and more acidic ocean water will propogate the resulting noise more efficiently. A 2023 study out of the Royal Netherlands Institute for Sea Research predicted that these changes could mean that by the end of this century shipping noise could be “five times as loud” as it is today in some ocean regions.
A lot of underwater noise is incredibly loud. For instance, Naval sonar can hit well over 200 decibels and has been implicated in several mass whale strandings, confirmed by the U.S. Navy itself. But loudness is only part of the problem for undersea creatures. A related, but distinct noise threat is the growing ubiquity of sonic intrusions, which drastically shrinks the sensory worlds of species that depend on listening for survival. Research on the ecological importance of underwater soundscapes and the impacts of noise have gained momentum in recent decades—boosted by lawsuit settlements between environmental groups and the Navy.
Studies show that as underwater noise rises, such as when big ships pass by or during pile driving for offshore construction, many aquatic species have trouble foraging for food, struggle to communicate (or just give up), and have surging stress hormones. None of these impacts are as directly harmful or dramatic as mass whale strandings, but they degrade the habitats of aquatic species, including many that are already struggling to survive, such as the North Atlantic right whale.
Noise = Waste
The biggest cause of shipping noise is cavitation around the propeller. While quieter propulsion systems are a big upfront investment for shipping companies, there is also an economic upside. Less cavitation means greater efficiency that will lower fuel bills and help meet other environmental targets such as reduced emissions. Many shippping companies already seek efficiency boosts by slowing down (“slow steaming”) during oceanic transits, which has a knock-on effect of less noise. In 2017, the Dutch shipping giant Maersk retrofitted cargoships to reduce fuel consumption and reduce emissions, and discovered that the upgrades also made the ships a lot quieter. A growing number of ports are experimenting with voluntary slow-zones in environmentally sensitive waters near the coast, and using monetary incentives to spur greener shipping that includes noise reduction.
A few years ago, the Natural Resources Defense Council made a short film about the worsening underwater noise problem, called The Sonic Sea (free trailer below, but it’ll cost a few dollars to watch the whole film).
Nature is Listening
Every species is affected by noise in different ways and at different times (when hunting, migrating, mating, and raising young, for instance), which means solutions can’t be one-size-fits-all and will require more research from the comparatively young field of sensory ecology.
Meanwhile, sensory ecologists have created new ways to guage the health of ecosystems by listening for things like earlier bird migrations or a sudden drop off in vocalizations from keystone species. Some scientists have started using AI to track the health of coral reefs by analyzing recordings of the teeming fish and snapping shrimp that call the reefs home and keep it thriving—or don’t when a reef is dying.
What’s more, these soundscapes actually help keep a reef healthy, because both baby reef fish and coral polyps start their lives in open ocean and find their way to a reef home partly by listening for it. In fact, a group of scientists at the Woods Hole Oceanographic Institution has had some success reviving sick reefs by playing recordings of healthy reefs to lure back the species essential to ecosystem function. Here’s a short NPR story about this work based on a 2024 study (linked above):
Nature Listening: What’s In It For Us?
Along with understanding the importance of nature’s sounds to ecosystem health, there’s mounting evidence that listening to nature benefits us humans, too. It’s well established that spending time in nature improves mental and physical health. For more than a decade, nonprofit networks of healthcare providers and park agencies have promoted “Parks Prescriptions” for a wide variety of ailments.
But, if nature is a wonder drug, what are its active ingredients? Comparatively little research has dug into the sensory components of parks prescriptions. For instance, how much of the benefit from a woodsy stroll depends on the excercise, the visual immersion, the nature listening, or the antimicrobial chemical compounds wafting from trees that we breathe in as we walk? More to the point of this newsletter, how much of the benefit might be lost if nature’s sounds were overwhelmed by noise?
One researcher trying to sort this out is Alex Smalley, and environmental psychologist with the European Centre for Environment and Human Health. While a doctoral student at the University of Exeter, Smalley led a Virtual Nature project to measure the health and wellbeing impacts of different virtual-reality nature experiences, with the goal of creating restorative environments for people who could not get themselves to real nature, such as people with disabilities or confined to hospitals.
Here is a video about the work (I had trouble embedding directly. Click the image, and the video will pop up in a new window):
Meanwhile, a handful of researchers have zeroed in on nature’s greatest acoustic hits—water and birdsong. The rush of rivers and other natural water sounds have largely been studied for their capacity to shield us from stressful sonic intrusions. Breaking waves, for instance, can transform annoying traffic noise into something people find neutral or even pleasant, according to Swedish researchers.
A 2022 study by environmental neuroscientists at the Max Planck Institute in Berlin found that listening to birds for several minutes reduced reported levels of anxiety, while listening to the same decibel levels of traffic noise led to spikes in depressive symptoms. And in a November 2024 study, researchers from the University of West England, found that people listening to a recorded “dawn chorus” of birdsong subsequently reported lower levels of stress and anxiety, whereas stress and anxiety rose in subjects who listened to the same birds overlaid with traffic noise. The stress and anxiety worsened when the noise was from faster-moving (noisier) traffic.
It’s a catch-22. The more people value time in nature, the more noise (and other pollution) they bring—from roads to snowmobiles to those bluetooth speakers blasting hikers’ playlists.
About a decade ago, the park managers of Muir Woods National Monument (a forest of towering, old-growth redwoods just north of San Francisco) wondered if noise from the growing crowds of visitors not only harmed the local birdlife (including endangered spotted owls) but also degraded the experience of these human visitors.
After some initial research indicated that visitors would welcome a more hushed experience walking among the awe-inspiring trees, park managers tested out “quiet please” signs that were made permanent when they not only reduced decibels, but consequently increased the audible birdsong, and received rave reviews in visitor exit surveys. (I snapped the photo of one such sign, which tops this section, during a visit to Muir Woods in the summer of 2024).
Wait…What?!
Acoustic Odds and Ends
A November 2024 article in National Geographic covered a “quiet counterculture” brewing among young people eager to escape their growing inundation in audible and digital noise. It highlighted trends such as distraction-free “silent walking” spread via Tik Tok, the growth of quiet-oriented meetup groups such as Peace in the Wild, “silent yoga,” and “no-talking coffee shops.”
Looking to create your own perfect soundcapes? Services such as Defonic and myNoise provide dashboards to create immersive, customizable soundtracks for your life—from the background hubub of a coffee shop to bamboo forests sounds to help you unwind after work to summer night sounds for relief from tinnitus.
KFC is jumping into the ASMR game with audio of chicken simmering in oil to mimic rainfall and help people fall asleep.
A research group out of Montreal is turning the brain signals of minimally responsive hospital patients into music in order to spot changes in patients’ consciousness after they’re engaged by “therapy clowns.” It’s really too much to explain in brief, so here’s a link to recent coverage of the research.
Finally, it’s 2025! The countdown is on to the publication of Clamor, the book, on May 20. To celebrate, there’s a Goodreads Giveaway you can enter to win a free copy until February 13. Feel free to pass it on!
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