JIM MCMAHON/MAPMAN®

For the first time, marine scientists have listened in on life in the deepest place in the ocean—a part of the Mariana Trench known as the Challenger Deep. It lies nearly 11 kilometers (7 miles) beneath the surface of the Pacific Ocean.

Researchers recorded the audio using a hydrophone. The underwater microphone had to be placed in a protective case to withstand the crushing pressure of seawater pushing on it at these depths. The device picked up the sounds of whales, underwater earthquakes, tropical storms called typhoons, and even ships. The scientists were surprised at how much noise from ships was audible so far down, says Robert Dziak, an oceanographer with the National Oceanic and Atmospheric Administration who led the mission.

Dziak and his team hope the recordings will help them better understand how this human-made noise pollution affects wildlife in the deep sea.