After listening to what they heard on microphones being dropped down in to the deepest depths of the ocean, a team of scientists reported listening to something quite normal: humming.

The researchers presented their findings at the American Geophysical Union's annual meeting in New Orleans, and they concluded they may have more work to do. It seems to be associated with a daily migration from an area of the ocean known as the mesopelagic zone to the surface, according to Gizmodo.

Past studies have estimated 10 million tons of phytoplankton live in this area between 200 and 1,000 meters below the surface. Their daily trip may be a mechanism to avoid being eaten, and the sound could be their means of coordination.

"It's not that loud, it sounds like a buzzing or humming, and that goes on for an hour to two hours, depending on the day," Simone Baumann-Pickering, an assistant research biologist at the University of California, in San Diego, said in a news release. "I think a large array of (marine) animals will show in the next 10 to 20 years that they are capable of producing and receiving sounds."

Speaking with NPR, Baumann-Pickering offered a more amusing possibility, acknowledging it is mostly unknown.

"It's known that some fish are considered to be farting, that they emit gas as they change depths in the water column," Baumann-Pickering said. "We're just scratching the surface in terms of understanding how important sound is."