Beneath Antarctic sea ice, a plume of super-cold brine sinks and grows a hollow tube of ice all the way to the ocean floor, freezing everything it touches. The BBC filmed one forming for the first time in 2011.
BBC Earth's time-lapse from Frozen Planet: a descending brinicle reaches the seabed and ices over starfish and urchins alive. The first footage of its kind.
A downward-growing hollow icicle enclosing a plume of brine. The overview of how they were first explained in 1974 and filmed in 2011.
As sea ice freezes, it expels salt into a cold, dense brine that sinks and freezes the seawater around it into a growing tube.
Why brinicles need still water, the right depth and salinity, and why the brine inside can stay liquid at temperatures far below normal freezing.
A physics paper arguing the self-assembling ice tube is a cousin of the chemical gardens grown in labs, driven by salinity instead of chemistry.
A 2023 Royal Society Open Science study builds the first numerical model of brinicle growth, matching the strange shapes seen under the ice.