The voice of eelgrass

Eelgrass in Puget Sound makes a noticeable bubbling sound as it expires oxygen on sunny days during the spring and summer.

A hydrophone captures the sound of eelgrass. Photo by Jeff Rice.
A hydrophone captures the sound of eelgrass. Photo by Jeff Rice.

Wade out into the shallows of Puget Sound on a warm, sunny day and put your ear close to the water. You might catch the faint, champagne-like bubbling of eelgrass. Take a listen to an underwater recording made at the Padilla Bay National Estuarine Research Reserve. A hydrophone captures the sound of oxygen bubbling from eelgrass leaves as the plant absorbs and photosynthesizes the sun's rays.

Eelgrass is one of the linchpins of the Puget Sound ecosystem, providing key habitat for species like shellfish and juvenile salmon. Scientists compare its importance to that of old-growth or tropical forests because of the variety and number of species that depend on it, and the plant is so vibrant that you can actually hear it "breathing." This respiration also makes eelgrass and other seagrasses exceptional "carbon sinks" for greenhouse gasses. A study published in 2012 in the journal Nature shows that seagrass meadows absorb massive amounts of carbon from the atmosphere—even more than terrestrial forests. 

Update: Read about my eelgrass presentation at the Acoustical Society of America Conference in 2016. 

Recorded by Jeff Rice with support from the Acoustic Atlas at Montana State University. Special thanks to Si Simenstad, Ron Thom, Katie Harrington and the staff of the Padilla Bay National Estuarine Research Reserve for their advice on this recording.   

Read more about eelgrass.

About the Author: 
Jeff Rice is the managing editor of the Encyclopedia of Puget Sound.