A diver works on a hydrophone device on the seafloor
The seafloor is alive with sound, and divers attach hydrophones to the seafloor in Florida Keys National Marine Sanctuary to listen in. Photo: Kayelyn Simmons under FKNMS permit #2016-111A1

A coral reef is a bustling community with snaps from shrimp, grunts from fish, and even the occasional click of a dolphin. Understanding the sounds on the coral reefs can help scientists look at diversity and the population of animals on the coral reef. They can also shed some light on how humans use the reef, such as listening to the hum of a boat engine going by.

Scientists put underwater microphones, called "hydrophones," underwater to record the soundscape or sounds of a particular location. This project was started in 2018, and scientists have been examining the sound information to translate sound into real information about the health of this ecosystem.

Researchers can also listen for how the sounds around coral reefs change as the reefs and ocean changes. If a coral reef gets quieter, there might be less animals that are calling it home. If coral restoration is successful in a location there might be more diverse sounds recorded by the equipment.

a redgrouper fish underwater

Hum, Crackle, Knock: Monitoring Reef Habitats in Florida Keys National Marine Sanctuary

Learn more about the Soundscape research in Florida Keys National Marine Sanctuary.

black and white fish swim around a science instrument on the seafloor

Sanctuary Soundscape Monitoring Project (SanctSound)

Learn how NOAA and the U.S. Navy are working to better understand underwater sound within the National Marine Sanctuary System.

A scuba diver holding a cylindrical piece of scientific equipment and attaching it to a structure affixed to the seafloor

Can Scientists Train Machines to Listen for Marine Ecosystem Health?

Researchers are testing the use of artificial intelligence and machine learning technologies to detect changes in ecosystem health.