PALAOA - What does the Southern Ocean sound like?
PALAOA stands for Perennial Acoustic Observatory in the Antarctic Ocean. However, Palao is also the Hawaiian word for whale and, indeed, the research station can make the songs of the ocean giants audible by means of underwater microphones. The small research container is unmanned and located not far from the Neumayer Station on the ice shelf of Atka Bay in the Antarctic. All acoustic signals from the underwater world are recorded from here. And under the ice there is a lot to hear: a number of marine mammals that live in the Antarctic Ocean communicate, hunt and navigate with the help of sounds. They include the killer whale and the largest animal on Earth, the blue whale.
Since nearly complete darkness prevails in the Antarctic winter, biological investigations are possible there only to a limited extent. PALAO, however, does not depend on visibility conditions and records year round, 24 hours a day, what goes on in the water under the ice shelf. Scientists can not only hear the voices of marine dwellers, the animals themselves are constantly surrounded by background noises: ice floes rub against each other and drift across the ocean, large pieces of the ice shelf tumble with a thunderous crash into the water and yearly the Polarstern sails past to bring supplies to the Neumayer Station. All these events leave traces in the records and show very clearly that the ocean is by no means as quiet as it looks.
Listen to the sea
You can hear whistling Weddell seals, clicking killer whales as well as the rare and little-researched Ross seal here.
The sounds made by the ice itself are particularly fascinating. There are singing icebergs, colliding ice floes and calving ice shelf.