A brinicle resembles a hollow pipe of ice reaching down from an ice sheet above the water. Inside the pipe is the super-cold, super-saline water being produced by the growth of the ice above. A brinicle can, under the proper conditions, reach down to the seafloor. However:
- the flow of super-cold brine from the icepack overhead must continue
- the surrounding water must be significantly less saline than the brine
- the water cannot be very deep
- the overhead ice pack must be still
- currents in the area must be minimal or still.
If the surrounding water is too saline, its freezing point will be too low to create a significant amount of ice around the brine plume. If the water is too deep, the brinicle is likely to break free under its own weight before reaching the seafloor. If the icepack is mobile or currents too strong, strain will break the brinicle.
Should a brinicle reach the seafloor, it will continue to accumulate ice as surrounding water freezes. The brine will travel along the seafloor in a down-slope direction until it reaches the lowest possible point, where it will pool. Any bottom-dwelling sea creatures, such as starfish or sea urchins can be caught in this expanding web of ice and be trapped, ultimately freezing to death. Source
Captured by BBC cameramen Hugh Miller and Doug Anderson while filming for the Frozen Planet series.
Ice Finger of Death Filmed in Antarctica
by Ella Davies, BBC Nature
A bizarre underwater “icicle of death” has been filmed by a BBC crew.
With a time lapse cameras, specialists recorded salt water being excluded from the sea ice and sinking. The temperature of this sinking brine, which was well below 0C, caused the water to freeze in an icy sheath around it.
Where the so-called “brinicle” met the sea bed, a web of ice formed that froze everything it touched, including sea urchins and starfish. The unusual phenomenon was filmed for the first time by cameramen Hugh Miller and Doug Anderson for the BBC One series Frozen Planet…
(read more: BBC Nature)
* Thanks to njwight for letting us know about this :3