Scientists have determined the cause of mysterious noises emanating from Mariana Trench. A new study shows that the noise may be coming from a baleen whale and may be a new type of call which had never been heard before. However, the scientists have not able to decipher the meaning of these sounds.

A 3.5-second recording of the strange sound was captured by an autonomous unmanned vehicle called Passive Acoustic Ocean Gliders, which ventured deep into the Mariana Trench. The clip was believed to have five different types of sounds. The recording was given the nick name of the Western Pacific Biotwang.

The recordings consisted of frequencies ranging from ultra-low 38 hertz to high 8,000 hertz.  

"The low-frequency moaning part is typical of baleen whales, and it's that kind of twangy sound that makes it really unique. We don't find many new baleen whale calls," Sharon Nieukirk, senior faculty research assistant in marine bioacoustics at Oregon State, stated.

There are speculations that the sounds are related to Dwarf Minke whales. These whales are a type of baleen whales, which are known for generating different types of calls in different regions. However, scientists do not have much information about minke whales at low latitudes. It is likely that the publication of these calls may help in generating more data for further exploration.

The recordings were made during different sessions in 2014 and 2015. Up to 326 of these calls were recorded during the dives between October 14 and November 6, 2014. The calls had around five minutes interval between them. Another set of 110 calls was collected in the period between March and April 2015.

The Mariana Trench is located between Japan and Australia. It is considered to be the deepest known area of the Earth's oceans. Some of these areas are as deep as 36,000 feet.