Quieting the Anthropocene Seas – Part 2

6/4/26 – The necessary quest to be quieter in and on the oceans

sleeping Weddell seal, McMurdo Sound, Antarctica / author photo

Hello everyone:

Given my topic these few weeks, I thought I’d note that World Oceans Day is this Monday, June 8th. Find an event near you, and check out the U.N.’s beautiful video announcement about why celebrating the ocean matters.

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:

The Crowded Radio Dial

Oddly enough, I first learned about bioacoustics in the quietest place on Earth: Antarctica. In the late 1990s, a researcher/composer/sound artist named Douglas Quin visited McMurdo Station to do some pioneering studies on the underwater soundscape in McMurdo Sound. At that point, I’d never thought about sound as a structural component of ecological communities, but Quin explained that animal species who rely on sound create their own space on the audio spectrum. To thrive, they need to hear and be heard. This is particularly true in dense habitats, like a rainforest, where the cacophony of animal noise is like a crowded radio dial. Each sound-dependent bird, animal, or insect species evolves their own radio station.

In Antarctic waters, though, there are very few species. The opportunity for those species to broadcast is extraordinary. And no animal takes more advantage of this than the Weddell seal. They can be heard making the most otherworldly sounds all across the dial (and beyond – some of their sounds are ultrasonic).

Take a listen to a quick clip here:

For the full experience, though, try a full two-hour immersion in Weddell seal singing, complete with video spectrogram. I very highly recommend giving it a listen. It’s beautiful and bewildering. As a reminder of how well sound travels underwater, most of the seals in this long recording were a half-mile away from the hydrophone.

If you can, consider listening to this recording as you read the rest of this essay. Keep the volume low, though; there are some loud surprises.

Haunted by Leaf Blowers

The natural acoustic environment of today’s oceans has evolved over at least 40 to 50 million years. The animals of the ocean, whether whale or coral polyp, sole or grouper, alewife or anchovy, have likewise had millions of years to evolve within that environment. Humans aren’t very good at contemplating millions of years, but take a moment to consider how incredibly small a single century is amid those millions. (A hundred years is .0022% of 45 million years.)

That century is all it has taken modern culture to drown out much of the ocean chorus.

It's as if the crowded oceanic radio dial with its marvelous diversity of music has been overpowered by a single station broadcasting engine noise and explosions for an audience that isn’t listening. Because we’re not underwater, we don’t hear the problem we’re making.

And as I noted last week, we forget that sound is an essential part of living for other species. To hear one very common example of the problem, listen to this 25-second clip from the Port of Vancouver, documenting orcas trying to communicate as a ship passes. (Check your volume before you click: the audio is loud.)

To empathize, simply imagine the most annoying or disruptive environmental noises in our lives: construction areas, chain saws and motorcycles, heavy traffic, trains rattling by and planes taking off. We all deal with noise, but not the way it’s experienced underwater in the noisiest places (day and night in shipping lanes and ports), where it has been pervasive, dominant, and increasing over the last several decades.

Because we’re not there listening, and because we’re sight-dependent apes who don’t really know what it means to be a sound-dependent fish, mammals, or invertebrates, we also don’t understand that in some cases our noise pollution can have population-scale impacts. Our noise not only impacts individuals, but also threatens entire species, habitats, and ecosystems. Imagine an army of leaf-blowers haunting your neighborhood day and night, all year long, for your entire life, making it hard to feed, mate, and raise your young.

Here’s a helpful infographic with four comparative ocean soundscapes: the natural, the noisy, and two imagined futures:

from The Soundscape of the Anthropocene Ocean

Worse Than You Think

A tugboat in motion is loud, producing about 170 decibels (dB). An oil tanker is even louder, at about 200 dB. But nothing comes close to a seismic airgun at 250 dB, which can be heard underwater over an area of 115,000 square miles.

For a landlubber reference, a gas-powered leaf blower is about 75 dB from fifty feet away, 100 dB if you’re running it. Thunderclaps and running chainsaws hit our ears at about 110-120 dB. If you were 25 meters away from a jet on take-off, your eardrums might be ruptured by the 150 dB it produces.

Anything below 70 dB is considered safe (if still annoying) for human ears, but remember that sound travels four to five times faster and farther underwater, and that a lot of marine life has more sensitive hearing than we do. (Adding insult to injury, a warming ocean transmits sound even faster.)

But the final kicker in this decibel data I’m throwing at you is that decibels are measured on a logarithmic scale, which means that the numbers I listed above are far worse than you thought. Loudness doubles for every extra 10 decibels. Thus, a sound 20 dB higher than another is four times louder, and a sound 30 dB greater is eight times louder. A seismic airgun at 250 dB is 100 dB greater than a jet at take-off and thus about a thousand times louder.

There are three problems with human noise underwater. The primary one is that, in much of the ocean, our noise is everywhere and all the time. The second problem is that much of our noise occurs on the same frequencies needed by the broad and beautiful variety of ocean life. And third is the incredible loudness of our worst noise, particularly sonar and airguns. (Loudness is not inherently unnatural. Those of you listening to the Weddell seals won’t be surprised to know that some of their noises rival the dB of a jet engine.)

Here’s some NOAA audio of seismic airguns. Incredibly, what you’ll hear is being emitted about 1500 miles from the recording microphone. (For some reason, the recording has been sped up 10x. Airgun blasts are typically spaced about 10-15 seconds apart):

But for the full effect, listen to this 16-second clip of a single blast, up close, followed by the clicks of echosounders:

Some Solutions

So what can we do about our noise in the oceans? Solutions, such as they are, come in three categories: noise avoidance (stopping the noise), noise reduction (improving technology so less noise is created), and noise-quieting (making the sound harder to hear).

Let’s take the offenders one at a time, starting with the loudest.

seismic airguns in action / credit: Australian Institute of Marine Science

SEISMIC AIRGUNS

The noise from seismic airguns dominates the ocean soundscape. It is essentially an echolocating technology, borrowed from marine mammals and now heedlessly weaponized against them, every ten seconds for weeks or months at a time for any given survey, with a hundred or more ships doing these surveys around the globe each year.

Just this week, an excellent interactive Times article explains in a series of illustrations how seismic surveys in the Gulf of Mexico fill the region with noise and impact the tiny remaining population of endangered Rice’s whales. The article allows you to hear the noise of seismic surveys overlapping with the calls of Rice’s whales, and visualizes the distance that noise travels and where the whales have gone to hide from it.

As we all know, the future of life on Earth will be shaped by whether we stop searching for fossil fuels and leave most of those carbon-rich substances in the ground. One benefit of that is never discussed: The faster we wean ourselves off fossil fuels, the faster the primary use of seismic airguns will become obsolete.

To get there, we need to continue making policy that 1) accelerates the energy transition, 2) reduces energy consumption and plastic production, and 3) makes the offshore search for fossil fuels harder to permit. These are beyond the scope of this essay, but I can at least point to the now incredibly rapid rise of renewables - solar, wind, batteries in particular - across the globe. (We are much better, though, at reimagining consumption than reducing it.)

I’d like to say that there has never been a better time to push for strict regulation of airgun use. But there are two realities getting in the way. First, here in the U.S. the Trump administration is burning hundreds of billions in a desperate attempt to bolster an industry that knows its time is limited. That effort will fail eventually - though not soon enough - because the economics of energy now favor renewables. And that’s the second reality: It’s quite likely that a decline in investment by banks for oil and gas exploration will succeed where policy has not. Since seismic airguns exist mostly to search out new fossil fuel deposits below the sea floor, their usage will diminish as investments shrink.

To the extent that fossil fuel prospecting and other research continue, though, a better technology is required. The answer there may be marine vibroseis, which uses a vibrating diaphragm-like device to send a similar but milder dose of energy into the sea floor. The sound is spread over a longer wavelength with a deep hum rather than a loud bang. These machines “gently” vibrate the seabed rather than violently disturbing the entire water column. Testing has begun, but the technology is still unproven, in part because it has been underfunded and understudied. An old article in Hakai explains how the inventor of seismic airguns developed marine vibroseis as a solution to the problem he created.

shock-test for the USS Ford with a 40,000 lb bomb, 100 miles off the Florida coast / credit: US Navy/MCS3 Riley B. McDowell

MILITARY EXPLOSIONS

Only military explosions, mainly from training and testing exercises, shake up the ocean soundscape more than seismic airguns. To give one example, a 2018 press release from the Center for Biological Diversity noted that permits issued to the Navy for a five-year period would “harm marine mammals 12.5 million times” in waters off California and Hawaii. This includes damage from sonar and ship strikes too.

Occasionally the Navy uses major explosions to shock-test ships. These will kill or damage fish, invertebrates, and marine mammals that are miles away. And as I detailed last week, Russia’s unprovoked war in Ukraine – with extreme noise levels from explosions and sonar – has been absolutely devastating for dolphins and other marine animals.

Because of the scale and institutional nature of the powers at work here, again we’re dependent on good policy to put protections in place. The good news is that constant vigilance (and lawsuits) from environmentalists and conservation-minded politicians has prompted the Navy to include marine mammal safety in their planning. The shock-test I mentioned above, for example, included extensive planning and surveying (before, during, and after) by a team of observers, researchers, and veterinarians. And a recent permit from the National Marine Fisheries Service for the Navy in the waters off the U.S. northwest requires some additional protective measures.

That said, these measures are merely softening the brutal status quo rather than reducing the large-scale harm. Those observers are watching for whales and dolphins within a kilometer or so of the ship, though the explosion was audible for thousands of miles.

Short of reducing naval activity or convincing the Navy to do their training and testing via computer simulation, there’s not much else to be done other than continuing to push for greater restrictions on where, when, and how the explosions are done.

Weddell seals below the ice / credit: changehali, Flikr via Wikimedia Commons

That’s it for now. Next week I’ll explore the harms and solutions related to sonar, shipping noise (propellers especially), wind farms, private boats, and more. Stay tuned to this topic, especially if you own a boat. I’ll dig into options for quieting your own presence on the water.

For now, remember that like the songs of Weddell seals, our presence on the planet can be strange – even bizarre – without being so harmful.

Thanks for sticking with me.

In other Anthropocene news:

As always, there is the astonishing Chloe Hope and Death & Birds, and this week it is “Sometimes… I am the sea,” a gorgeous short ode to the importance of paying attention to real life. Chloe sings in her chains like the sea (as Dylan Thomas advised), and brings us sentences to swim toward amid the chop and swell of this life:

When we do not share a language with the beings we love most in the world, they themselves become a language we must learn. What cannot be spoken must be sensed; listened for through eyes, skin and the vast catalogue our bodies keep of the many thousands of tiny observations that love sees us make.

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From rebecca hooper and between two seas, “learning to save a whale,” another beautiful post from the Orkneys, this one detailing a day spent being trained to respond to strandings of marine mammals. Rebecca articulates both the work and its meaning beautifully:

I will carry this story around with me like a talisman, a guard against the pervasive sense that the world is becoming less kind, that people are becoming less kind, because if ordinary folk will put themselves through this, through three hours rocking waist-deep in a dark and stormy ocean, for the chance that they might give a porpoise a second chance at life (the porpoise did re-find his balance and swim back to the deep)—well, then there is light.

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From the Times, a lovely little story about a pair of endangered New Zealand parakeets - kākāriki karaka, to be precise - who have been so busy mating and successfully raising chicks (55 in the last two years) that they’ve increased the population of their species by more than 10%.

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From Inside Climate News, a good-news account of how the vast, beautiful Okefenokee swamp on the Georgia/Florida border is close to being given UNESCO World Heritage Site status. The Okefenokee is the largest blackwater swamp in North America, five times the size of Atlanta, inhabited by 250 bird species and 64 reptile species, including an estimated 15,000 alligators. It’s built on thousands of years of slowly accumulated peat, a rarity in the subtropics.

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From bioGraphic, a timely article on how the Trump administration’s tariffs are motivating Canada to seek other trade partners, which means increased shipping in the St. Lawrence Seaway, which in turn means far more noise and other threats to marine life. As always, bioGraphic does a great job of writing well about the natural world and our threats to it, and in this case that means noting how much impact ocean noise can have:

Though charismatic creatures like whales are the poster children for the issue, sonic pollution impacts everything along the food chain. “All animals, from mussel larvae to whales, are potentially affected by noise,” Cauchy says.

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From Anthropocene, “Does Energy Efficiency Reduce Carbon Emissions?,” a fascinating discussion of how major gains in efficiency may or may not be leading toward a low-carbon future. One of the principles in question here is whether or not the Jevons Paradox - a 19th century observation of how efficiency often leads to increased consumption - will apply to an electrified world powered by renewables.