Southern Sounds

The Southern Ocean is punctuated by an amazing variety of sounds — chirps and clicks and notes that sound like they were created for a sci-fi movie. Yet they’re produced by seals and whales, by grinding icebergs and cracking ice sheets, and by things that scientists are still trying to identify.

A set of underwater microphones is recording the sounds of the Southern Ocean around the clock, all year long. It’s a project known by the acronym PALOAO, from the Hawaiian word for whale, that’s conducted by the Alfred Wegener Institute in Germany. It’s operated from a remote station atop the Ekstrom Ice Shelf in Atka Bay off the coast of Antarctica.

There are few human-made sounds — only an occasional ship bringing supplies to a nearby research station. Many creatures use sound to navigate, hunt, and “talk” to each other, so the lack of human-made sounds provides a pristine environment for scientists to study.

The sounds will help scientists track the motions and behavior of many species all year long — Weddell seals, Ross seals, and others.

The sounds also reveal the natural environment — collisions between icebergs, and the rumbles and splashes of ice breaking off the shelves and falling into the sea.

And they reveal sounds that no one can explain — some audible mysteries from the cold depths of the Southern Ocean.