If you’ve ever explored meditation or been coached on how to ease anxiety, you’ve probably been told to picture a calm ocean view, or maybe even what it’s like to be under the water. You can buy recordings of gentle surf or underwater sounds to help you sleep. We tend to think of the ocean as a quiet place, and it must be especially quiet at the bottom of all that water, right?
Not so. Last July scientists from the National Oceanic and Atmospheric Administration in the US, Oregon State University, and the U.S. Coast Guard used a titanium-shielded microphone to record sound at the bottom of the Challenger Deep, the deepest point of the world’s oceans, eleven kilometres below the surface. The equipment picked up noise from faraway earthquakes, a typhoon that passed overhead, and even the propellers of a passing cargo ship—from eleven kilometres below! Of course, we already knew that whale song can travel vast distances across the oceans, too. Salt water is just a terrific medium for sound waves to travel through, which is probably why whales, dolphins, and a number of other creatures use sound to navigate the sea as well as bringing and keeping their social groups together.
The thing is, we humans aren’t the shy and retiring type. To be honest, we can be pretty loud. And that goes for the things we do in the world’s oceans, especially activities like deep drilling for oil and, soon, even louder seismological exploration to find deposits of oil. It doesn’t take a marine biologist to figure out that the noises we make will be disruptive to marine life over a huge area. Not just the dolphins and whales that use echolocation, but even the small creatures of the sea bed that are responsible for stirring up nutrients from the sea floor that other species need, and even provide dinner themselves for larger predators. Some marine researchers from the UK studied how loud human noises affected Manila clams, brittle stars, and small lobsters called langoustines. The noises made the lobsters stop making their burrows and the clams to shut themselves up tight as a…well, clam. You’ll know how they felt if you’ve ever had a construction company doing roadwork in your neighbourhood, or suffered through a blasting crew using dynamite to get rid of some inconvenient rock. The difference is that we expect to get some benefit from noisy projects like that—lobsters and clams don’t. Worse, we don’t yet know whether sea creatures recover from such disruptions or if there might be serious long-term damage to some species.
Something else could also be compounding the process. The huge amounts of carbon we keep throwing into the atmosphere isn’t just affecting climate, it’s also making the oceans more acidic. There have been concerns that more acidic seawater not only affects creatures that use sound for their survival (like the so-called “snapping shrimp”) but might actually pass sound waves even better, creating a louder ocean. That opinion isn’t held by everyone (see this study from the Woods Hole Oceanographic Institution) but the possibility means a lot more study should be done before we do damage we can’t undo.
What’s the science fiction angle on this? Well, living and working in undersea cities and factory installations has been an SF trope for years, and though we’ve only taken baby steps along that path so far, the depletion of land resources means there’s a good chance we’ll turn to the sea for a lot more than just oil in the coming centuries. Farther down the road, it’s even possible that we’ll make a presence for ourselves on celestial bodies like Jupiter’s moons Europa and Ganymede, or the Saturnian moon Enceladus., which are thought to have oceans of their own, maybe including forms of life. So while we’re learning ways to cut back on our other forms of pollution, let’s make sure we don’t ignore the sound pollution that could be just as damaging in its way. That’s just being good citizens of our planet and our solar system.
You know those neighbours who drive down the street blaring a hip hop bass line that vibrates your windows, and throw loud pool parties until 3:00 in the morning every summer weekend? We don’t want to be them.