We were told the sound was from snapping shrimp, end of story

Monday, December 31st, 2018

Lauren and Simon Freeman, oceanographers with the US Naval Undersea Warfare Center in Rhode Island, noticed strange pings in the Hawaiian Islands:

They perceived that the soundscape of healthy, protected reefs was dominated by low-frequency sounds (the kind typically made by fish and other large animals), while degraded reefs were noticeably higher pitched.

“We were told the sound was from snapping shrimp, end of story,” says Simon. “[But] there seemed to be a correlation between the sound and the proportion of algae covering the seafloor.”

Determined to dig deeper, the Freemans and their colleagues housed red algae in tanks devoid of clamorous crustaceans or other animals. The sounds they picked up matched the high-frequency sounds of struggling reefs.


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.


  1. Graham says:

    Just send back a message – “One ping only, please. We’re trying to hear the whales.”

Leave a Reply