Scientists baffled by deep sea noise

BOSTON -- Mysterious giant beasts may lurk in the darkest depths of the ocean making whale-like noises that are baffling scientists.

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 4800km 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.

One suggestion is that the sound is coming from giant squid, which live at extreme depths of up to four kilometres. Although dead giant squid have been washed up on beaches, and tell-tale sucker marks have been seen on whales, there has never been a confirmed sighting of one of the elusive cephalopods in the wild.

The largest dead squid on record measured about 18m including the length of its tentacles, but no one knows how big the creatures might grow. However Phil Lobel, a marine biologist at Boston University in Massachusetts, US, doubts that giant squid are the source of Bloop. "Cephalopods have no gas-filled sac, so they have no way to make that type of noise," he said. -- Sapa-DPA