Scientists from Germany's Alfred Wegener Institute for Polar and Marine Research noticed clear acoustic signals when recording seismic signals to measure tectonic movements and earthquakes on the Ekstroem ice shelf in Antarctica.
They traced the signals to a 30-by-12-mile (50-by-20-kilometer) iceberg that had become stuck on an underwater peninsula. Water flowing through the iceberg emitted a frequency of around 0.5 hertz, too low to be heard by humans without enhancement.
"Once the iceberg stuck fast on the seabed it was like a rock in a river," said scientist Vera Schlindwein. "The water pushes through its crevasses and tunnels at high pressure and the iceberg starts singing."
