Tag Archives: Glaciology

Amusing Monday: Underwater icicle freezes starfish

The headline on BBC Nature News calls an underwater ice formation the “Brinicle Ice Finger of Death.”

“Brinicle” is short for “briny icicle,” while “Ice Finger of Death” is a dramatic title for a fascinating natural phenomenon found in Antarctica and captured in stunning time-lapse photography for the BBC One series “Frozen Planet.” Click here for the video.

The video shows a finger of heavy water reaching down from the surface and then advancing across the sea floor, encasing starfish and sea urchins in unexpected ice.

The water coming off Little Razorback Island near Ross Archipelago contained a high salt content, the result of separation as ice freezes at the surface. Because of its high concentration of salt, the runoff water was denser and colder than the surrounding ocean (well below the freezing point of fresh water). As the brine drained off the island, it caused the seawater to freeze around it as the brinicle advanced.

The phenomenon had been noted before, but finding a place where a brinicle was forming and setting up the film equipment was a feat in itself, as photographer Hugh Miller explained to reporter Ella Davies of BBC Nature:

“That particular patch was difficult to get to. It was a long way from the hole and it was quite narrow at times between the sea bed and the ice. I do remember it being a struggle… The kit is very heavy because it has to sit on the sea bed and not move for long periods of time.”

Frisky seals in the area barged into the scene, breaking off pieces of the brinicle and messing with the film gear, but eventually the crew got the dramatic video they were seeking.

The series “Frozen Planet” apparently is not yet available in the United States. The clip shown in the video player above can be viewed on the BBC Nature page if the YouTube version does not work.

Since the clip above was posted on YouTube last Wednesday, it has gone viral, with more than 4.9 million viewings. (The clip, which was copied from the BBC website, has since been taken down.)