Brinicles — The Ocean’s “Ice Fingers of Death”
Reaching down like frozen fingers from the water’s surface, where the so-called “brinicle” meets the sea bed, a web of ice forms that instantly freezes and kills everything it touches, including sea urchins and starfish.
The formation of brinicles, also known as ice stalactites, is dangerous to marine life. Sea ice is frozen fresh water because the salt in ocean water does not freeze with it. As the water freezes, high concentrations of salt are excluded. This brine – super saturated salt – gets pushed out of the ice through channels. Some of it gets pushed up and out, leaving a slightly salty layer on top of the sea ice, but much of it gets pushed down, back into the water.
As this extremely cold brine leaves the sea ice, it sinks in a descending plume and freezes the relatively fresh seawater it comes in contact with. This forms a fragile tube of ice around the descending plume into what is called a “brinicle” – an icicle of brine. These look like icicles hanging from the underside of the ice. If the brinicles keep growing and extending down to the ocean floor, they form a web of ice that freezes everything. Hence the nickname “ice fingers of death”. An amazing video which captures the formation of a brinicle was first filmed in 2011 for the BBC series Frozen Planet.
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