How Sound Is Helping Bring Coral Reefs Back to Life
When most people think of coral reefs, color comes to mind. But new research is showing that sound might be just as critical to their survival.
A study published in Royal Society Open Science has revealed that underwater speakers playing the natural soundscape of a healthy reef—think fish calls, snapping shrimp, and low-frequency ambient noise—can significantly improve coral larvae settlement rates on degraded reefs. Some sites saw up to a sevenfold increase in settlement when these healthy reef sounds were introduced.
What Makes a Reef “Sound” Healthy?
Researchers from Woods Hole Oceanographic Institution spent years recording the subtle acoustic ecosystems of coral reefs across the Caribbean. They found that vibrant, biologically rich reefs had distinctly complex sound signatures. Fish create rhythmic pops and pulses by manipulating their swim bladders, while the ever-present crackling of snapping shrimp adds texture to the underwater audio environment.
These sonic cues act as natural lighthouses for coral larvae drifting in ocean currents, helping them decide where to anchor and grow into reef-building adults. And for corals—creatures that stay in one place for life once settled—choosing the right home is everything.
Restoring the Reef, One Soundwave at a Time
In the experiment, scientists placed coral larvae on test platforms across three different reef sites near St. John in the U.S. Virgin Islands—one healthy and two degraded. Near each site, solar-powered underwater speakers played back recordings of reef soundscapes collected nearly a decade earlier.
The results were striking. Coral larvae near the speakers settled at nearly twice the rate of those farther away. And the effect declined with distance, confirming that proximity to the sound was key. Even more interesting, the research team suspects the larvae might be sensing the sound waves through their outer layers, although the exact mechanism isn’t yet understood.
What This Tells Us About Sound and Environment
This isn’t just a marine biology story—it’s a reminder of how sound environments influence behavior, migration, and survival across species. The idea that a reef can lose its voice as it degrades, and that we can potentially bring it back using carefully curated audio, is powerful.
For those of us working in sound, it’s a compelling example of how sonic design extends far beyond storytelling or media. In this case, sound becomes a functional tool—a guide for life beneath the surface.
Photo Credit: Dan Mele, Woods Hole Oceanographic Institution
Looking Ahead
As coral reefs continue to face stress from rising ocean temperatures and other environmental pressures, methods like acoustic enrichment could play a role in helping them recover. The technology is scalable, and underwater speakers can cover large areas, making this a promising complement to other restoration efforts.
While this approach is still in its early stages, it adds another dimension to the role of sound in shaping natural systems. Whether in a reef, a forest, or a film, sound shapes how we—and other species—experience the world.
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