The Antarctic and Arctic sounds rarely heard before
"Singing" ice, a seal that sounds like it is in space, and a seismic airgun thundering like a bomb. These are some of the polar noises released by two marine acoustic labs in Germany.
Underwater microphones were attached to floats left in the Arctic and Antarctic for two years.
It is part of a project involving the organisation Cities and Memory to highlight how climate change is impacting the region.
Video by Gwyndaf Hughes and Georgina Rannard, BBC Climate and Science
Sound credit: Helmholtz Institute for Functional Marine Biodiversity and the Alfred Wegener Institute