In 2015, we started to explore a surface depression that ran across the Milne Ice Shelf using ice-penetrating radar. Crossing back and forth along this depression we mapped the underside of the ice shelf and found a sub-ice shelf channel where water from the epishelf lake flowed out to the Arctic Ocean. When we melted a small hole through the 10 m thick ice at the top of the channel, we made a startling discovery. Using a remotely operated vehicle (ROV) we found that there was a ‘bench’ of ice right below the ice channel which we never were able to observe in our radar surveys. Much to our wonder, we discovered that the surface of that ice bench contained sediment and many benthic (bottom-dwelling) organisms living right there in the middle of the ice shelf! Researchers have found animals underneath ice shelves before (far from the open ocean and in the complete darkness). However, to our knowledge, nobody has found a community of benthic organisms living within an ice shelf. These communities seem to be fairly well-established and they must get their food from the sediments that drift through the water column from the epishelf lake. Below we have a video of the animals we found in the channel.

The following animals were identified by Philippe Archambault, Cindy Grant, Lisa Treau de Coeli, and Laure de Montety from Université Laval:  Brittle stars (Ophiuridae), Worms (Polychaeta), Scallops (Pectinidae), Sponges (Porifera), Anemone (Actiniaria), Sea cucumber (Holothuroidea), Soft coral (Nephtheidae), Hydrozoa, Arctic cod (Boreogadus).  We were slated to collect some specimens this summer to determine how old they were and further describe this wonderful ecosystem.  However, COVID-19 and the ice shelf break-up have thwarted these plans.

Cross section of the ice shelf channel from Jill Rajewicz’s ice-penetrating radar survey (blue line). In some locations the radar return was not interpretable, however we know there is a horizontal bench of ice within the channel where the benthic animals live from our ROV surveys. We can only guess at the morphology of the channel and think there may be two options – a meandering current caused a bench (top) or a tunnel exists in the the ice where water from the epishelf lake flows (bottom). Diagram courtesy of Drew Friedrichs and Jérémie Bonneau