BBC Nature features an article about a time-lapse sequence shot as a part of the Frozen Planet series currently on air. Filmed under the ice at Little Razorback Island, near Antarctica’s Ross Archipelago, the camera crew captured the growth of a “brinicle”, which formed as a result of sea water freezing around brine released from sea ice. As this brine was well below zero and much denser than the water surrounding it, it formed a frozen icicle hanging underneath the sea ice. Due to its temperature, the brinicle is lethal to anything that it touched, freezing them instantly.

In the article, cameramen Hugh Miller and Doug Anderson talk about how awkward it was to get the equipment into place, and the fact that The large weddell seals in the area had no problems barging past and breaking off brinicles as well as knocking over the filming equipment.