Scientists Finally Find Source Behind Strange Noises Coming From Pacific Ocean's Deepest Trench

Mysterious Sounds in the Pacific Ocean

Researchers have discovered the origins of the mysterious sound heard all around the Mariana Trench in the Pacific Ocean, since 2014. In 2018, several experts came together and analyzed the sites where bizarre noises were heard and concluded that they came from a species of whales, Newsweek reported. After it was first picked up by an acoustic survey, experts named the sound 'biotwangs'. For four years, despite their suspicions, scientists could not match the sound to any being. All the findings regarding the sounds were published by the research team in the journal Frontiers in Marine Science.

Biotwangs

Researchers defined biotwangs as mechanical-sounding screeches familiar in texture to the noises made by spaceships in Star Trek, Newsweek reported. Biotwangs were first noted during a survey undertaken by Oregon State University. An autonomous seaglider picked up the noise. Along with Mariana Trench, the sound can also be heard in other parts of the Pacific Ocean. Ann Allen, a research oceanographer at NOAA Fisheries stated that experts from the beginning were speculating that biotwangs came from whales because similar previous mechanical mystery sounds were discovered to have been coming from the mammal. The experts describe the captured sound as a low grumble followed by a high-pitched note, BBC reported.

Bryde's Whales

Bryde's whales are a kind of baleen whales and measure between 40 and 55 feet in length. These whales primarily reside in warm, tropical, and subtropical waters. They prefer to live in small groups or alone, with some choosing to migrate while others spend their entire life in the same area. These mammals usually prey on small schooling fish, plankton, and crustaceans, with their filter-feeding technique. In this technique, mammals use their plates to capture the targets, by filtering them from water.

The Biotwang and Bryde's Whale Connection

In 2018, researchers confirmed in their study that the sound was coming from Bryde's whales. The team released some sonobuoys (devices used to detect underwater sounds) in the Mariana Trench. They noted that a Bryde whale was observed in the surroundings every time the noise was picked up. "With nine confirmed Bryde's whale sightings in conjunction with sonobuoy recordings we demonstrate that the previously identified Biotwang call is made by Bryde's whales," the researchers wrote in the paper. "Biotwangs were observed in association with a single whale, mom-calf pairs, and groups of up to four individuals with and without a calf. The only Bryde's whale sighting without Biotwang recordings was of the largest observed group (five animals), which was the only sighting of multiple individuals that did not contain a calf." Experts believe that the Bryde whales make these calls to each other, while they are traveling underwater, BBC reported.

Climate Change and Bryde's Whales

Researchers found that biotwangs increased in 2016, when El Nino was happening, and started to occur in particular areas like the Northwest Pacific, Newsweek reported. This implies that many Bryde's whales were migrating to that particular area during that time. El Nino is a phenomenon that impacts climate patterns because of the warming up of the ocean, USGS reported. As per researchers, the sounds made by whales during the period of such intense climate change correlate to their health during that particular time. "As climate change accelerates, we expect stronger and more variable El Nino/La Nina conditions, which may impact how far the whales have to go for food and how hard they have to work to find it, which can impact the health of the population. So we would like to try to tie in the acoustic data with environmental conditions to investigate how climate change is impacting these populations," Allen said.