Teasing sounds apart in an underwater habitat is like trying to listen for the crackle of a single street light in the middle of Times Square. So when scientists thought they heard the sound of algae on a coral reef, their hunch was met with some skepticism. How could something seemingly so sedentary ring out over some of the ocean’s chattiest (and most flatulent) inhabitants, sloshing waves, and noisy humans? With bubbles, it turns out.
Like the plants that help us breathe, algae also photosynthesize. Underwater, that process of converting sunlight and carbon dioxide into energy and oxygen sends tiny bubbles spiraling toward the surface. And according to new research, when each bubble detaches from the seaweed, it goes ping. The scientists behind the discovery suggest that, like a heartbeat heard through a stethoscope, measuring that unique sound could be a new way to monitor the health of a coral reef.

(Hakai)