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Otherworldly Biological Noise Recorded Deep In Mariana Trench

Scientists have recorded a strange, otherworldly noise in one of the deepest parts of the Mariana Trench that they are unable to positively identify. The noise was recorded using autonomous underwater drones called passive acoustic ocean gliders which dive down to some of the deepest parts of the ocean armed with underwater microphones (called hydrophones) in order to record the myriad noises of the deep.

The Mariana Trench is the deepest known part of the world's oceans.

The Mariana Trench is the deepest known part of the world’s oceans.

This particular noise was recorded off the coast of Guam in the 2014, and is thought to be from a species of whale. However, there are still aspects of the whale theory that don’t entirely add up.

The noise has been dubbed the “Western Pacific Biotwang” and has been described in a recent publication in the Journal of the Acoustical Society of America. The authors are confident that “these complex sounds were produced by a biological source” which is speculated to be a type of baleen whale, but that note a definitive source is ultimately still a mystery:

We hope others will be able to identify this call in past and future data, and in time identify the source of this sound. More data are needed, including genetic, acoustic, and visual identification of the source to confirm the species and gain insight into how this sound is being used.

The baleen whale theory is complicated by the fact that the sound has been recorded year-round, while baleen whales have previously been known to make vocalizations only during mating season. Furthermore, acoustic analysis has shown that some of the metallic-sounding higher frequencies in the Western Pacific Biotwang are not typically found in whale calls.

Minke whale mating calls are the current theory for the mysterious noise, although there are holes in this theory.

Minke whale mating calls are the current theory for the mysterious noise, although there are still holes in this theory.

Could this sound be made by some type of unknown sea creature? While a whale is the most plausible explanation given what we know, there is still much we don’t know about the Earth’s deep oceans. Furthermore, it was recently discovered that the Earth likely contains vast unexplored underground oceans full of unknown and undiscovered lifeforms. Given that many mysteries of the deep oceans are thought to be responsible for many of the strange sounds heard both underwater and above ground, it’s possible this new noise could be something other than a whale entirely.