Beware the Bloop



This was published 19 years ago

Beware the Bloop

Mysterious giant beasts may lurk in the darkest depths of the ocean, making whale-like noises that are baffling scientists, it was disclosed today.

Researchers have nicknamed the strange unidentified sound picked up by undersea microphones ``Bloop''.

While it bears the varying frequency hallmark of marine animals, it is far more powerful than the calls made by any creature known on Earth.

In 1997, Bloop was detected by sensors up to 4,800 km apart, New Scientist magazine reported.

That meant it had to be much louder than any recognised animal noise, including that produced by the largest whales.


Although dead giant squid have been washed up on beaches, and telltale sucker marks have been seen on whales, there has never been a confirmed sighting of one of the elusive cephalopods in the wild.


However Phil Lobel, a marine biologist at Boston University in Massachusetts, US, doubts that giant squid are the source of Bloop.



``Though you can never rule anything out completely, I doubt it.''

Nevertheless he agrees that the sound is most likely to be biological in origin.

The system picking up Bloop and other strange noises from the deep is a military relic of the Cold War.

In the 1960s the US Navy set up an array of underwater microphones, or hydrophones, around the globe to track Soviet submarines.

The listening stations lie hundreds of metres below the ocean surface, at a depth where sound waves become trapped in a layer of water known as the ``deep sound channel''.

Here temperature and pressure cause sound waves to keep travelling without being scattered by the ocean surface or bottom.

Most of the sounds detected obviously emanate from whales, ships or earthquakes, but some very low frequency noises have proved puzzling.

Scientists believe many of these - given names such as Train, Whistle, Slowdown and Upsweep - can be explained by ocean currents, volcanic activity , or the movement of Antarctic ice. Bloop, however, remains a tantalising mystery.


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