Baltic Sea

Music from their ears



An ESF fisheries ecologist and a musician colleague have developed a new way of telling the story of how the lack of oxygen in the world’s oceans stifles the growth of economically valuable cod – they set the story of the fish to music and make them “singâ€. ”

Dr. Karin Limburg of the ESF’s Department of Environmental Biology and Elizabeth LoGiudice, an environmental educator and musician from New York’s Hudson Valley, use data sonification to create messages about hypoxia and the state of the oceans. They went public with their story and posted a “Cod Songs” feature on the website for Project Breathless, funded by the National Science Foundation, to help understand the effects of low oxygen dead zones in lakes, estuaries and oceans to improve.

Limburg leads the interdisciplinary project breathless team. Her research has long focused on how fish ear stones, called otoliths, grow and contain traces of elements that reflect the chemistry of the water in which the fish lived. So far, scientists have used X-ray fluorescence and mass spectrometry analysis to extract the history of fish growth and movements in different environments. Limburg has teamed up with LoGiudice to set these stories to music.

“For cod we can ask questions – where did he go, what did he see, was he ‘happy’? – and get answers through trace element chemistry, â€said Limburg. “And we wondered if by sonifying our data we could create effective messages about hypoxia and the state of the oceans.”

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

“Listening to data from fish’s ears is fascinating and a very interesting way to educate people about fish’s problems,” said LoGiudice.

The couple hosted a webinar for the Global Ocean Oxygen Network (GO2NE) earlier this year, which drew 285 attendees. Last spring they repeated the presentation of Dr. Andrea Feldpausch-Parker at the ESF. Feldpausch-Parker commissioned their 38 students to develop an experimental design to test the use of cod songs as an alternative communication strategy.

Limburg and LoGiudice produced the unique melodies from the chemical records of the otolith, one of which dates back around 5,000 years to the late Neolithic. Limburg received it from a former student who is now an osteoarchaeologist in Sweden. Trumpet tones rise when the fish ripens and swims from the coastal waters of its youth into the less salty, open waters of the then healthy Baltic Sea. Barium, which is more common near the coast, was represented by organ music, which swelled when the fish returned to near-shore waters where it was apparently caught.

A cod caught in 1939 sings a happy tune. Trumpet tones and a lively marimba beat tell the story of his physical growth, which follows the rhythm of the seasons until it stops abruptly when the fish is caught.

However, the song of a 21st century cod sounds like the soundtrack to a lonely person’s nightmare. Caught in deoxygenated waters, the fish’s otolith contains manganese, which shows exposure to hypoxia and magnesium, which reflects the fish’s slowed growth rate. The trace chemicals combine to form deep, pounding piano notes and high-pitched, swirling violin sounds that sound like they come straight from a frightening scene in a thriller.

According to Limburg, sonification is becoming a popular form of data interpretation. Not only does it serve as a tool for communicating with non-scientific audiences, but it can also be used to recognize patterns and serve as a supplement or alternative to data visualization. Her work with LoGiudice is part of the NSF research project that focuses on studying the effects of marine hypoxia on fish species around the world.

By Claire B. Dunn – ESF researcher