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Music from Their Ears

ESF scientist, colleague make songs from the life stories of Baltic cod

Dr. Karin Limburg (left) and her colleague, Elizabeth LoGiudice, in the field. The pair collaborated on using data from fishes’ ears to make music and create a message about hypoxia and the condition of the oceans.

An ESF fisheries ecologist and a colleague with expertise in music have developed a new way to tell the story of how oxygen depletion in the world's oceans stunts the growth of economically valuable cod — they put the fishes' history to music and let them "sing."

Dr. Karin Limburg of ESF's Department of Environmental Biology and Elizabeth LoGiudice, an environmental educator and musician from New York's Hudson Valley, are using data sonification to create messages about hypoxia and the condition of the oceans. They have gone public with their story, launching a "Cod Songs" feature on the website for Project Breathless, which is funded by the National Science Foundation to increase understanding of the impact of low oxygen dead zones in lakes, estuaries and oceans.

Limburg leads the interdisciplinary Project Breathless team. Her research has long focused on how fishes' earstones, called otoliths, grow and incorporate traces of elements that reflect the chemistry of the water in which the fish lived. Until now, scientists have used X-ray fluorescence and mass spectrometry analysis to extract the story of the fish's growth and movements among different environments. Limburg partnered with LoGiudice to put those stories to music.

"For cod, we can ask questions — where did it go, what did it see, was it 'happy'? — and get answers through trace element chemistry," Limburg said. "And we wondered if we could, by sonifying our data, create effective messages about hypoxia and the condition of the oceans."

Limburg had the data. LoGiudice had the musical know-how to run the data from a spreadsheet through an app that set the numbers to music; then she manipulated it further through music-editing software.

"Listening to data that come from fishes' ears is intriguing and a very interesting way to inform people about the issues fish are facing," said LoGiudice.

The pair delivered a webinar earlier this year for the Global Ocean Oxygen Network (GO2NE) that drew 285 attendees. This past spring, they reprised the presentation for Dr. Andrea Feldpausch-Parker's environmental communications class at ESF. Feldpausch-Parker tasked her 38 students with developing an experimental design to test the use of cod songs as an alternative communication strategy.

Limburg and LoGiudice produced the unique tunes from the otolith's chemical records, one of which dates back some 5,000 years to the late Neolithic. Limburg obtained it from a former student who is now an osteoarchaeologist in Sweden. Trumpet notes soar as the fish matures and swims from the near-shore waters of its youth into the less salty, open waters of then-healthy Baltic Sea. Barium, more plentiful close to shore, was represented by organ music that swelled when the fish returned to near-shore waters, where it was apparently caught.

A cod caught in 1939 sings a happy tune. Trumpet notes and a peppy marimba beat tell the story of its physical growth, which follows the rhythm of the seasons until it stops abruptly when the fish was caught.

The song of a 21st-century cod, however, sounds like the soundtrack to a lonely person's nightmare. Caught in low-oxygen waters, the fish's otolith contains manganese that reveals exposure to hypoxia and magnesium that reflects the fish's slowing growth rate. The trace chemicals combine into low, pounding piano notes and shrill, swirling violin tones that sound like they came straight out of a scary scene in a thriller.

Limburg said sonification is becoming a popular form of data interpretation. In addition to serving as a tool to communicate with non-scientific audiences, it can be used to detect patterns and serves as a complement or alternative to data visualization. Her work with LoGiudice is part of the NSF research project focused on studying the effects of marine hypoxia on fish species around the world.

By Claire B. Dunn - ESF Science Writer