Brinicles are hollow, downward-growing tubes of ice that form under the sea ice, nicknamed "icicles of death" because they flash-freeze any sea creatures they touch. They are formed when seawater trapped in sea ice freezes, expelling a super-salty brine that is denser and colder than the surrounding seawater. As this brine flows downward, it freezes on contact, creating a hollow ice tube that grows and can spread across the seabed, trapping and freezing slow-moving marine life like starfish and sea urchins.
Formation process Salt expulsion: When seawater freezes, the salt is pushed out, creating pockets of extremely salty, super-cooled brine.
Descent: This brine is denser than the surrounding seawater and sinks beneath the ice pack.
Growth: As the brine sinks, it freezes the surrounding seawater on contact, forming a tube-like structure around itself. The inside of the tube can melt from the brine, while the outside freezes and grows, causing the brinicle to extend further down.
Seabed impact: When a brinicle reaches the seabed, it spreads out and can cover a large area, forming a sheet of ice that traps bottom-dwelling creatures.
Other characteristics and significance "Chemical gardens": The formation of brinicles is similar to a "chemical garden," where reactions in a saline-rich environment can lead to the formation of complex structures. Origins of life: Some scientists believe that brinicles may have played a role in the origin of life on Earth, as they provide a cold environment with concentrated chemicals, and a similar process could be happening on icy moons like Europa. Observation: Brinicles were first filmed forming in situ in 2011, although they have been known about since the 1960s.
