According to Wikipedia, Frozen Planet is a 2011 British nature documentary series, co-produced by the BBC and The Open University. The seven-part series focuses on life and the environment in both the Arctic and the Antarctic.
In one episode they made, they captured on film for the first time an underwater occurrence called a brine icicle, or brinicle in short.
A brinicle is an ice stalactite formed when a flow of extremely cold, saline water is introduced to an area of ocean water.
“Ice Finger” forms beneath the sea and kills everything in its path
|A closer look of the developing brinicle.|
Dubbed as the ‘icicle of death’, a brinicle extends towards the seabed and creates a web of ice which kills sea urchins and starfish that get trapped in it.
According to DailyMail, although the existence of brinicles has been known since the 1960s, it is the first time it has been caught on camera. So go ahead and watch the video to see his amazing underwater phenomenon unfold!