What's that mysterious underwater hum? It might be fish gas.

What the sounds of the deep sea tell us about the lives of marine creatures.

|
Dave Ellifrit/ The Center for Whale Research/AP
TA new baby orca whale is seen swimming alongside an adult whale in the Haro Strait between San Juan Islands, Wash., and Vancouver Island, Dec. 16. Ecologists are sounding the alarm that orca populations living off the coast of Europe could face extinction as a result of banned chemicals leaching from aging construction materials.

Using underwater microphones, called hydrophones, marine scientists several years ago picked up a puzzling, faint humming sound a thousand feet deep in the Pacific Ocean.

For years, no one could explain it. It didn't match the typical mating call of male humpback whales, nor the clicking of dolphins and other underwater creatures. And it appeared on a predictable schedule: for a couple of hours after sunset, and then for a couple more at dawn.

It was “more as if you're sitting on an airplane and it's humming, buzzing,” Simone Baumann-Pickering, a marine biologist at the Scripps Institution of Oceanography at the University of California in San Diego described to National Public Radio (NPR).

This week Dr. Baumann-Pickering and her team announced that they have linked the strange sound with the migration of billions of fish, crustaceans and squid from the dark depths of the Pacific – where they spend their days eluding predators – to the surface at night to feed. Baumann-Pickering estimates that the combined weight of the migrating fish adds up to 10 billion tons, possibly the largest migration of vertebrate animals on the planet, as NPR reports.

What actually produces the sound is not yet clear, though Baumann-Pickering suspects that it could be that the fish are humming or buzzing to communicate travel plans. Or maybe, she says, they are just passing gas.

"It's known that some fish are considered to be farting," Baumann-Pickering told NPR, "that they emit gas as they change depths in the water column." Fish have gas in their bladders to control their buoyancy.

Baumann-Pickering and other researchers will continue to study the largely unexplored cacophony of sounds resonating through our oceans to better understand how deep-sea creatures live and communicate.

"It’s a part of the world we know little about," David Gallo, an oceanographer at Woods Hole Oceanographic Institution in Massachusetts told Weather.com. He said Baumann-Pickering’s latest findings are among "the most fascinating research to come along in some time." 

Underwater sounds are a particularly important area of study, as scientists have learned in recent years that too much man-made noise in the ocean – from ship traffic, oil and gas exploration, scientific research, and military sonar – can have harmful effects on its inhabitants.

Science has already shown that loud human activity in the ocean damages the hearing of whales, sometimes with fatal consequences. It interferes with their survival tactics.

The cries and clicks of whales are critical to their survival. They use these sounds to communicate with each other when looking for food, or trying to travel safely along uneven coastlines, or to and from breeding grounds. Some make loud noises to drive away prey.

"We are now starting to recognize chronic ocean noise as a ubiquitous habitat-level stressor,” Rob Williams, a marine conservation biologist for Seattle-based Oceans Initiative told Weather.com.

“If human-generated noise is masking this hum or buzz, we may be tipping the balance between predator and prey, and changing the way that ecosystems function,” Dr. Williams said.

Scientific research of ocean sounds and their impact on marine life already has led to international guidelines aimed at hushing ship traffic.

In September, the US Navy said it will use sonar and other explosive training exercises more responsibly off the coasts of California and Hawaii to avoid harming dolphins, whales, and other marine mammals.

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to What's that mysterious underwater hum? It might be fish gas.
Read this article in
https://www.csmonitor.com/Science/2016/0225/What-s-that-mysterious-underwater-hum-It-might-be-fish-gas
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe