For the first time, we can observe the formation of an “ice finger of death” through impressive images.

It is rare today to discover a phenomenon completely new to science, one that expands our knowledge of the world in unique and wonderful ways. But just as has happened in recent years with isolated tribes, invisible caves and sea beasts, the formation of Antarctic brinicles, also known as “ice fingers of death”, was recently presented to armchair adventurers in the form of some awesome images. .

Brinicles are otherworldly, finger-like structures that extend from floating sea ice to frigid Antarctic waters. While scientists have known about their existence since the 1960s, they are rarely observed in real time. Ice fingers only occur under specific conditions in the Earth’s polar regions, under blocks of floating sea ice, making them not only difficult to track but almost impossible to capture on camera. This is what makes the following images from the BBC series Frozen Planet (season 1, series 5) so special.

Unlike frozen fresh water, ocean surface ice is made up of two components. During the freezing process, the water excludes most of the salt, leaving the ice crystal relatively pure. However, this causes the presence of excess salt. Because it needs much lower temperatures to freeze, the remaining salt water remains in its liquid form, creating highly saline brine channels within the porous block of ice.

A diver examines a large brinicle. (Image credit: Andrew Thurber, Oregon State University)

A brinicle forms when floating sea ice cracks and leaks saline water solution into the open ocean below. Since brine is heavier than the water around it, it sinks to the ocean floor while freezing the relatively fresh water it comes into contact with. This process allows the brinicle to grow downward, creating that resemblance to a finger.

Dr. Andrew Thurber, one of the few scientists who has seen brinicle growth firsthand, describes a fantastic scene marked by brinicles crawling downward. “They look like blown glass upside-down cacti,” he says, “like something out of Dr. Suess’s imagination. “They are incredibly delicate and can break with the slightest touch.”

On Little Razor Back Island in Antarctica, this 3m-deep area is home to thousands of brinicles that often extend to the seafloor. Among them live thousands of amphipods that can be seen swimming in this image. Although they are normally only close to the ice, when disturbed, the amphipods swarm, like a bee’s nest. (Image credit: Andrew Thurber, Oregon State University)

For nearby sea creatures, however, the fragile ice sheets hide a deadly weapon: as shown in the video, a brittle can reach the seafloor and, as it grows from this point, could trap several living creatures. deep down, like the sea. urchins and starfish, freezing them too.

“In areas that used to have brines or under very active ones, small pools of brine form, which we refer to as black pools of death,” Thurber says. “They may be quite clear, but they have skeletons of many marine animals that have been randomly put into them.”

Diver Rory Welsh swimming alongside a 2m long Brinicle in McMurdo Sound, Antarctica. (Image credit: Andrew Thurber, Oregon State University)

The scientific study of brinicles is in its early stages, but for the first time we have video evidence of the development of these mysterious icy fingers of death.