Neutrino fishermen catch whales, too
|Photo courtesy of G.Pavan/CIBRA
Biologist Gianni Pavan joined the Ocean Noise Detection Experiment in 2000 to help physicist Giorgio Riccobene distinguish various marine background noises from the sounds neutrinos make when they interact with ocean water. But his focus abruptly switched from signal to background when he realized they were hearing far more marine life than anticipated.
“There was such a quantity of so many different sounds, it was like a party,” Riccobene says. “Gianni was listening and kept saying, ‘This is a dolphin! This is a sperm whale!'”
The pair picked up the signals by lowering hydrophones from docks on the coast of Catania, Italy, to depths of 2000 meters. This is significantly deeper than biologists traditionally listen.
The sperm whales were an especially exciting find. Though biologists knew that whales travelled through the Mediterranean, the team's recordings revealed record numbers of whales. This provided new data about sperm whale migration, group behavior, and seasonal activity.
A refurbished version of the experiment, known as LIDO for Listening to the Deep-Ocean Environment, will expand physicists' understanding of marine background noise while monitoring the impact of human noise on marine life in the Mediterranean. Pavan and Riccobene also propose to install acoustic sensors in the future deep-sea Mediterranean observatory KM3Net, which will bring together particle physicists, geophysicists, seismologists, and marine biologists.
“Our research is a never-ending story,” Pavan says. “We continue to improve our detection instruments, and every time we go out to sea we discover something new about where these animals are, how they move, and why.”
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