Beneath the surface of the icy waters of Antarctica, a symphony of sounds can be heard. The Perennial Acoustic Observatory in the Antarctic Ocean, or PALAOA, records the sounds of whales and other sea life, icebergs and mysterious phenomena from an unmanned research station located near the Neumayer Station on the ice shelf of Atka Bay.
Humpback whales (Megaptera novaeangliae) are know for the mating songs of the males, most often heard in tropical waters.
The Antarctic minke whale or southern minke whale (Balaenoptera bonaerensis) is a type of baleen whale, recently identified as the source of a mysterious duck-like sound.
Killer whales (Orcinus orca), also known as orcas, emit a wide array of whistles and clicks for echolocation.
Male Weddell seals (Leptonychotes weddellii) emit whistling sounds to defend females, and both males and females emit chirps.
Scientists don't know how icebergs make these sounds, but they are related to the icebergs' movement.
Now and then, large pieces of the Antarctic ice shelf break off in a process known as calving.
The collision of two icebergs produced the loudest sounds ever recorded by PALAOA.
Scientists don't know the origin of many sounds recorded by PALAOA, or even whether they are man-made or not.