Can the ocean freeze? YES! And in one example it does so in an odd way. This strange formation of a "brinicle" is a result of a spiraling cone of ice built around freezing particles of salt water. A BBC crew filming Frozen Planet has captured the first ever footage of a brinicle forming. Brinicles can sprout when calm salt water becomes colder than the surrounding sea and begins to drift toward the ocean floor. They form because of the temperature difference between the cold, arctic air (-20 degrees celsius) and the relatively warm ocean water (-1.9 degrees celsius). When water flows up towards the surface it freezes and precipitates salt which increases the salinity of the water just below the newly formed ice. When the salt becomes concentrated it sinks due to its density creating brine channels. As this cold brine sinks, it freezes the relatively freshwater surrounding the plume forming very fragile tubes of ice which grow to form what we know as a brinicle. The brinicle instantly freezes the water around it, creating a tornado-looking structure that can spread across the sand below to engulf nearby marine animals, killing them or at least locking them in an annoying state of suspended animation.
Click here to read the BBC article associated with this film.