How the mournful songs of icebergs reverberate around the world

Icebergs produce some of the loudest natural noises in the oceans. Can we learn anything about their birth, life and death by listening in?

From the surface, the ice shelves of Antarctica are vast, white deserts – almost featureless save for a few ruts and crevices. Occasionally, cracks as long as a small country can widen and a piece breaks off, forming huge icebergs that drift out into the Southern Ocean.
Hemmed in by the sea ice that forms around the continent, and caught in vast traffic jams of fellow floating ice, the progress of these giant frozen slabs is slow. For months at a time, they barely move. Stand on one of these tabletop-shaped ice giants and only the occasional creak betrays their movement. But underwater, another story unfolds – the icebergs are singing.
When played at frequencies audible to human ears, it could easily be mistaken for whale song. But in fact, the noise is produced by the grinding and scraping of the craggy underside of these icebergs on the seafloor and as they rub against each other. The resulting song can be detected thousands of miles away in the far-off waters of the Indian Ocean.
“An iceberg plate works as a tuning fork,” says Alexander Gavrilov, a professor at the Centre for Marine Science and Technology at Curtin University in Australia. “The song frequencies depend on iceberg’s dimensions.”