‘Sonic kayaks’ monitor life underwater

An interdisciplinary team in the United Kingdom has designed a “sonic kayak” that researchers and citizen scientists can use to eavesdrop on the ecosystem below and obtain underwater sound and temperature data.

The system is designed to be cheaper and more versatile than conventional techniques used to monitor underwater sound.

“Anyone willing to get in a kayak and paddle around can use it,” said Joanne Garrett, a postdoctoral research associate at the University of Exeter and co-author on the paper published in PLOS Biology. “You just need to press go. It would record and the data could be analyzed by a researcher later.”

Garrett and her collaborators outfitted a kayak with a system that consists of a battery, computer, GPS, memory stick, temperature sensors, hydrophones and speakers. As kayakers paddle, they can hear and record sounds picked up by the hydrophones in the water, allowing them to listen in on animals, from snapping shrimp to dolphins, and monitor the effects of passing ships and other manmade sounds.

“It could help in monitoring ecosystem health,” Garrett said. “If it’s getting quieter or there are fewer sounds from animals, you might think that ecosystem health is deteriorating.”

The system also emits a sound that rises and falls to indicate temperature changes. Its temperature recordings could help researchers conduct fine-scale temperature mapping to monitor climate change and harmful algal blooms, she said.

Current underwater acoustic recording technologies are limited, Garrett said. Fixed systems moored to the seabed don’t cover much area, drifting devices don’t always go where researchers want them and manually-operated hydrophones require someone to hold them beneath the surface.

The sonic kayak records “while you’re going along,” she said. “I hope people use it to engage with life underwater and understand what’s going on down there.”