This undersea video looks like science fiction showing an icy finger of death killing everything in its path, but is a stunning portrayal of freezing point depression – with narrative by the inimitable Alec Baldwin of “30 Rock” fame on NBC.
A brinicle, or brine icicle, plunges toward the Antarctic seabed from the ice shelf above, killing everything in its path. This had never been filmed before Frozen Planet, premiering March 18 on Discovery Channel.
Here’s a brief description of what’s going on:
As the seawater freezes and salt is forced out of the pure ice crystal lattice, the surrounding water becomes more saline. This lowers its freezing temperature and increases its density. The lower freezing temperature means that the surrounding water does not freeze to the ice immediately, and the higher density means that it sinks. Thus tiny tunnels called brine channels are created all through the ice as this supersaline, supercooled water sinks away from the frozen pure water. The stage is now set for the creation of a brinicle.