Quieting the Anthropocene Seas
5/28/26 – We can, and should, stop making so much noise in the ocean
Hello everyone:
(Apologies for a second email, but the first went out by mistake with an early draft. This is the full version. You can discard the previous email.)
I’m away for most of this week and the next two, and so I’ve revisited, revised, and updated my three-part series on our ocean noise. It’s from three and a half years ago, when I had a tenth of my current readership, so it should be new for most of you. I think it’s one of my more interesting and lesser-known topics; let me know what you think.
As always, please remember to scroll past the end of the essay to read some curated Anthropocene news.
Now on to this week’s writing:
Sound is Light
I did some autobiographical math some time ago and realized that, despite having traveled widely, I’ve spent nearly my entire life within a few miles of the ocean. I can scarcely think of a time when I was away from a shoreline for more than a few months. Even in Antarctica, I spent most of my time on the edge of Earth’s southernmost port.
The ocean is an odd magnet for me, though. I don’t fish or sail, and despite a childhood in coastal Maine and Cape Cod I have never liked lounging on the beach with other pale flotsam. I’m drawn more to moving along its rough edges than to exploring the sea itself. Here in Maine I canoe between islands, and I walk shorelines. I walk, poke at natural things, pick them up and put them down, collect plastic fragments to throw away elsewhere, and stare out across the water before moving along again.
There’s a quiet, happy restlessness in my best relationship with the water’s edge, as if I’m reflecting back the wave energy lapping at my feet. But there’s a calmness too, the constantly renewing gift of that open horizon. The sea “sings in its chains,” per Dylan Thomas, and even in its most destructive surges that song feels to me like a lullaby.
Most of us experience the ocean as a visual spectacle, a vast and restless body for us to gaze upon, swim in, travel across, and occasionally look longingly into its depths. But the ocean is not the shallow sunlit edges we know. It is mostly those dark depths, a deep, dense, permanent night we have scarcely visited, much less mapped.
As a marine scientist says in an excellent short film from the Economist on deep sea mining, “If you’re thinking about what have we actually looked at on the sea floor, it’s less than 0.001%.” Only the top 150 to 200 meters of the ocean receive enough light for photosynthesis, and this sunlit zone only makes up 2% to 3% of the oceans. The “midnight zone,” starting 1000 meters deep, makes up 90%.
However little we know, we know a lot more now than when Rachel Carson asked, in her 1937 essay “Undersea,” “Who has known the ocean?”
Neither you nor I, with our earth-bound senses, know the foam and surge of the tide that beats over the crab hiding under the seaweed of his tide-pool home; or the lilt of the long, slow swells of mid-ocean, where shoals of wandering fish prey and are preyed upon, and the dolphin breaks the waves to breathe the upper atmosphere.
But sinking beneath the waves and opening your eyes doesn’t get you very far. The ocean realm is, for its inhabitants, a world often experienced less by sight and more by smell and sound. Fish and sharks might, for example, see a hundred feet, and smell something thousands of feet away, but they can hear a loud noise from miles away. Everything from plankton and corals to orcas and humpback whales rely on their acoustic perception. As one researcher told the Guardian,
Sound is light in the oceans. It illuminates the ocean for many animals.
A report from the Bureau of Ocean Energy Management (BOEM) explains further:
Many fishes, and at least some invertebrates, depend on sound to communicate with one another, detect prey and predators, navigate from one place to another, avoid hazards, and generally respond to the world around them.
Polluting the Whole Spectrum
Which leads me to an anthropogenic problem that’s not often discussed: our excessive underwater noise. From the point of view of ocean life, we are an incredibly loud and obnoxious neighbor, and we are everywhere. Shipping, military activity, oil and gas drilling, seismic exploration, fishing, wind farm construction, pleasure boating, whale-watching, and much more all create an underwater cacophony. The variety of sources - like large ships emitting low frequency noise, and small ships emitting high frequency noise - means that we pollute the whole spectrum.
Our relentless contamination of the soundscape changes feeding behavior, reduces reproductive success, impairs communication, and makes some areas unlivable. Imagine living with neighbors running their leaf blowers all day and night, all year long: that’s us.
The good news is that much of this can be reduced. Unlike other ocean threats - the overharvesting of fish, destruction of seafloor habitats from bottom trawling, the threat of deep seafloor mining, chemical and nutrient pollution, and especially the “deadly trio” (climate-related warming, acidification, and deoxygenation) - our noise problem in the ocean is in some ways a quick-fix, on/off problem. Parts of the problem are among the few low-hanging fruit of the Anthropocene crisis.
Even better news: When we reduce our noise, conditions for life in the ocean immediately improves. Becoming quieter in the sea increases biodiversity and fisheries productivity in inshore waters and improves the likelihood of survival for the large and charismatic keystone species (whales, dolphins, tuna, etc.) who are essential for a healthy ocean.
Here’s a helpful illustration of the ocean soundscape in the Anthropocene:
Acoustic Daylight
The ocean is an ideal acoustic environment. Sound travels about 1500 meters per second underwater, four to five times faster and farther than in air.
To live a normal life, marine mammals, fish, and invertebrates need “acoustic daylight” – my new favorite phrase – which is simply a quiet-enough environment to clearly hear and communicate. (If you’re an introvert, I’m sure you can relate…)
Large-scale acoustic daylight is particularly necessary for whales, as an NPR article pointed out:
Humpbacks are a chatty bunch. In addition to their well-known, melodious songs, they make "whups" and other noises, either to coordinate feeding or simply to stay in touch with each other. Sound can travel for miles underwater, sometimes hundreds of miles, much farther than a whale can see. “Whales use sound in almost every aspect of their daily life," [wildlife biologist Christine Gabriele] says. "Studying the underwater sound environment is really important because it helps us see the world the way the whales actually use it.”
Humpback whales have a music culture, with new songs sweeping through different populations around the world at different times. But, as the NPR article noted, that culture is harder to maintain now:
“More needs to be done," says Jason Gedamke, who manages the ocean acoustics program at NOAA Fisheries. "When you have animals that for millions of years have been able to communicate over vast distances in the ocean, and then once we introduce noise and have increased sound levels and they can't communicate over those distances, clearly there's going to be some impact there.”
“Vast distances” is not hyperbole. Whale song can travel for thousands of miles under the right circumstances. Those circumstances are called the SOFAR channel, a horizontal layer in the oceans (defined by temperature) which acts as a guide for low frequency sounds. Sound can be transmitted like a skipping stone for thousands of miles along this natural phenomenon. The “Heard Island Experiment” in 1991 emitted a signal from the Southern Ocean through the SOFAR channel, and it was heard at sixteen listening stations around this ocean planet, including Bermuda and Monterey.
Better, Quieter Neighbors
The ocean is a vast, dark place that’s notoriously difficult to study. How do we know that our noise is impacting life in the sea? From some scientific observations of those impacts, certainly, and some common sense, but also from opportunities to observe what happens when we become better, quieter neighbors.
After the 9/11 attacks shut down shipping on the U.S. east coast, stress hormone levels in North Atlantic right whales dropped. Twenty years later, cortisol levels decreased significantly for humpbacks in Antarctic waters when the pandemic kept the annual mob of 73,000 whale-watchers at home. At the same time, pregnant loggerhead turtles in Greek waters could enjoy the warmer shallows because they were no longer driven away by swimmers. Likewise, water quality, fish populations, and biodiversity all increased when Hawaii’s Hanauma Bay Nature Preserve kept the snorkelers away for nine months. And an early observation in the Port of Vancouver as the pandemic shutdown began found that noise levels were cut in half, making it easier for local orca pods to echolocate their prey.
The pandemic was an unprecedented opportunity to collect data in a quiet ocean and, in retrospect, to empathize with life in the sea. Having experienced the shutdowns ourselves, we can imagine the subsurface shift toward silence. We heard the decrease in traffic and the increase in birdsong, so we can understand how fish, mammals, and invertebrates would thrive in decreased cacophony.
The pandemic experiment in calming the oceans may not be repeated soon, but we shouldn’t ignore the truth about its benefits, or about our ability to make them permanent. As one conservation biologist told the Times, “No one can say anymore that we can’t change the whole world in a year, because we can. We did.”
An Ecocidal War
As global civilization surged back into motion, our noisy activity reestablished the underwater version of what ecologists call a “landscape of fear.” The term generally describes the impact of predators on prey behavior, but it also describes how so many species have to cope with or avoid our overwhelming noisy presence. On land, this is especially true around roads and highways. At sea, it’s everywhere.
The worst kind of acute ocean impacts have occurred in the Black Sea because of Russia’s war on Ukraine. A truly disturbing article from Mongabay about the ecocidal impact of the war explains that an armada of Russian ships and submarines with powerful sonar, not to mention incredibly loud explosions from the bombing of ships and ports, killed thousands, perhaps tens of thousands, of dolphins and other cetaceans. They began washing up in unprecedented numbers immediately after the war began.
There was simply no escape for the dolphins, with their incredibly sensitive hearing, in a war zone full of fast-moving, deep, low, violent explosions. I imagine what the dolphins experienced was like holding a stethoscope up to a jackhammer. Such violent noise causes physical damage, often fatal, to marine animals’ bodies, especially their ears.
No one knows what the final ecological toll will be, but the war is certainly removing far too many keystone species and likely destabilizing the Black Sea ecosystem, already at-risk, for generations to come.
Marine Traffic
What’s happening in waters off Ukraine is particularly ugly, but it’s only an extreme version of our Anthropocene soundscape.
How bad is the problem globally? It’s hard to say with precision, because the ocean is vast and the research is underfunded, but we know enough to know we should be changing our behavior. And we’ve known it for a while. As a 2021 Guardian article noted:
The damage caused by noise is as harmful as overfishing, pollution and the climate crisis, the scientists said, but is being dangerously overlooked. The good news, they said, is that noise can be stopped instantly and does not have lingering effects, as the other problems do.
That article was based on an analysis, “The soundscape of the Anthropocene ocean,” which analyzed over 500 studies on the impact of human noise on ocean life. Around 90% of the studies measured significant harm to marine mammals like whales, seals and dolphins. 80% of the studies noted impacts on invertebrates and fish. The Guardian cited some details:
The most obvious impact is the link between military sonar and seismic survey detonations and deafness, mass strandings, and deaths of marine mammals. But many uses of sound can be harmed, such as the hums that male toadfish use to attract females and the honks that cod use to coordinate spawning.
Baleen whales produce calls to help group cohesion and reproduction that can travel across ocean basins, and humpback whales sing complex mating songs that have regional dialects. Sperm whales and various dolphins and porpoises use sonar to echolocate prey. Other animals use sound to feed: some shrimps produce a “snap” sound to stun prey.
Over the past half century, the steady increase in shipping has made the amount of low-frequency noise on major cargo routes more than 30 times worse. It’s doubled every decade since the 1960s.
There are at least 60,000 commercial vessels at sea as you read this. That’s a mind-boggling number, but it’s only a partial accounting, since it doesn’t include some of the loudest offenders, like military ships and oil rigs, nor the vast numbers of local fishing and pleasure craft. For an astonishing real-time glimpse of just those commercial vessels, though, you can monitor them at Marine Traffic. Zoom in on any place on Earth where ships are sailing, and click on the icons for each vessel to learn more about it. The image above is a snapshot.
In contrast to the cheerful notion of “acoustic daylight,” the noise created by the legions of ships has been described as an “oceanic smog.” Coastal waters and oil/gas exploration zones are generally the noisiest areas, often dominating the natural ambient soundscape. The low-frequency wall of sound from shipping comes from the engines, the rippling of water around the hull, and especially from propellers. Scientists working around the Great Barrier Reef in Australia, for example, have learned that consistent motorboat noise can double the mortality for fish unable to hear predators.
Airguns and Sonar
Seismic airguns are used by the oil and gas industry (and by research vessels) to map the sea floor and the geology deep beneath it. Long rows of airguns are towed behind a vessel, releasing explosions of compressed air that are as loud as a jet at takeoff. These explosions are emitted every ten seconds, 24 hours a day, sometimes for weeks at a time. This work has been going on for decades, with each blast audible up to 2500 miles away.
One decade-long study found these sounds could be heard throughout much of the Atlantic Ocean up to 80% of the time over the course of a year. The disruption for whales is obvious, but the impacts reach the bottom of the sea and the foundation of the food chain, with one study finding huge impacts on zooplankton (e.g., krill larvae and copepods), which are the foundation of the ocean food web:
The team found that zooplankton abundance dropped by 64% within one hour of the blasts. And the proportion of dead zooplankton increased by 200–300% as far away as 1.2 kilometres — the maximum distance the researchers sampled. This suggests that the impact of the blasts could extend well beyond such distances…
Sonar, meanwhile, is ubiquitous. It’s used on military, research, and cargo vessels, on trawlers and lobster boats, and maybe even on your little fishing boat. Fish-finders, echo sounders, fishing net control sonars, side-scan sonars, multi-beam sonars, and other sonars for mapping the seabed topography are constantly searching the ocean, and while the high-frequency sounds don’t travel as far as low-frequency airgun explosions, and are above the hearing range of most fishes and invertebrates, there are innumerable sonar devices in service, and they are a disturbance to some fish, like shad and menhaden.
We’re Being Noisy Underwater
If I’ve given the impression that the ocean noise problem is limited to the particular sensitivities of sea life, it’s worth remembering that humans can be killed by noise as well. The shock waves from explosions, for example, wreak havoc with our bodies. It’s happening in Ukraine right now. Humans, dolphins, fish, and zooplankton are all soft-bodied creatures in a hard world.
It’s easy to feel that Anthropocene noise is happening in the deep ocean, at some distance from our daily lives, but it’s not that simple. Every time we board a ship, drive a car over a coastal bridge, or sit in a plane taking off over the water from a coastal airport, we’re being noisy underwater. When we purchase items shipped across the ocean, we’re being noisy underwater. When we use energy from offshore oil and gas, or offshore wind farms, we’re being noisy underwater. And when we eat fish caught by bottom trawlers, or any fishing boat, that’s us too. I don’t mean to make us all feel guilty. Rather, I mean to explain that, as with so much in the Anthropocene, we’ve been trapped by the choices offered by an ill-conceived civilization.
But as I’ve mentioned, there are some easy ways to reduce the noise and its impacts. And there’s some good news on the regulatory and technological fronts too. Most importantly, there’s ample evidence that ecosystems bounce back immediately once we become quieter neighbors. We have some solutions for this problem. And that’s what I’ll talk about for the next two weeks.
For now, I highly recommend you watch this excellent, thoughtful video from Vox. It will tie together everything I’ve just told you.
Thanks for sticking with me.
In other Anthropocene news:
From Bill Davison and Easy by Nature, “On the Boardwalk at Magee Marsh,” a beautiful depiction of a day spent in a crowded but amazing birding hotspot near Lake Erie. As always, Bill provides stunning bird photos to accompany his thoughtful prose that explores both the wildlife and the importance of the choices we make in their presence.
Likewise, from Bryan Pfeiffer and Chasing Nature, “Virtue in a Droplet,” another excellent account of Bryan doing remarkable fieldwork in service of seeing, and paying respect to, the details of nature that so few of us have the patience to discover or even pay attention to. Bryan’s field notes from his exploration of the real world - in this case tiny secretions from a parasitic plant in a Vermont bog - are always beautifully photographed and full of good-natured wisdom:
Purpose and grace may wait as well in the backyard, by the roadside, or in a crack in the pavement. It need not be rare or even beautiful — as long as it means something to you. So seek your orchid, your warbler, your butterfly.
From Michelle Nijhuis and Conservation Works, “Ecology in the Deepest Sense,” an excellent short editorial on the kind of guardrails we should be putting up around AI. She’s focused on conservation and journalism, but her central idea that these professions require humans to make human connections to best serve their audiences rings true for much of our lives. To this end, she cites Pope Leo’s recent encyclical on AI, Magnifica Humanitas:
Our task today is not only ethical or technical. It is ecological in the deepest sense, for it concerns a new dimension of our common home. AI is already an environment in which we are immersed, as well as a force with which we must engage. For this reason, merely regulating it is insufficient; it must be disarmed, welcoming and accessible.
From Bill McKibben and The Crucial Years, “Just my imagination,” another of his fine personal letters on this era’s crucible in energy and politics. This one digs into the role of the imagination in the climate fight, whether in opening up the minds of those still on the sidelines, waking up politicians to the role they need to play, or just having some fun along the way. McKibben, as always, has a gift for talking open-heartedly about the work ahead:
I confess that I, like the Pope (and that’s a fun phrase to write) have great faith in the powers of the particularly human imagination. Climate change, to me, has always seemed like a test of whether or not the big brain was a sound adaptation: obviously it can get us in a lot of trouble, but can it get us out of that trouble? The longer I live, the more I’m convinced that the answer to that question has mostly to do with the size of the heart that brain is attached to. In the end, “imagination” is about enlarging that heart.
Both McKibben and Anthropocene magazine report on a new study that finds burning coal around the globe not only contributes substantially to the ugly mess that is our warming atmosphere, but also emits enough sulfur particles to weaken solar rays enough to reduce the effectiveness of solar panels by about 6%.
From Nautilus, a short cute good-news story about native species rebounding beautifully on Lord Howe Island in Australia after a successful rat and mouse eradication project. The rodents had been there for a century, and while full recovery will be long and some plant or animal populations may never resemble what they were before the rats arrived, already invertebrate numbers have increased by 50%.
From Vox, an update on the Ocean Census project, which has accelerated the search in the deep oceans for all the life we’ve never seen, but which is threatened by the prospect of deep ocean mining. Take a few minutes to examine the “alien” species of the deep ocean, which remind us how little we know about the Earth amidst our zealous transformation of it. Here, for example, is a likely new species of ping pong ball sponge:
Hi everyone, sorry for the mix-up with this week's post. Substack does this odd thing of reverting back to an earlier draft if you're working on two different computers. I usually catch it, but for the first time in more than five years of writing the Field Guide I've had to send out a corrected post (on my phone while traveling). Thanks for your understanding. - Jason
Thanks for this essay. I learned a lot that I didn't know about ocean noise-pollution. Enjoy your holiday!