Sounds Below Two Meters of Sea Ice at 90° N

Sea ice harmonics convey illusory echoes and vibrations.

In July 2024 at 90° N my acoustic equipment slid into a hole 15 cm in diameter that our team had drilled into the sea ice. Midnight sun tossed shadows at the fog, slowing the wind just enough. My fingers trembled, but not from the frigid temperatures. I couldn't imagine what I might hear here, beneath the ice floes at the top of the world. Science aside for a moment; icy droplets blurred white and blue ice, and my headphones hung in my hand at my side. 

Clearing my gaze, I knelt beside the hole and arranged my equipment. My headphones found my ears, and the underwater soundscape leapt into my mind. 

The underwater radiated noise (URN) emanating from the icebreaker that brought me to this place dominated the acoustic symphony for only a few seconds before geological and biological signals took center stage. Thanks to its owners' penchant for sustainability, its noise profile was as good as an icebreaker's could be. Ponant's Le Commandant Charcot has a Cleanship label issued by Bureau Veritas (as do all Ponant vessels). This certification includes requirements for reduction of underwater noise pollution. 

The ice was closed to all but a few of us—scientists taking samples—interrupting ourselves often, because what else could we do but pause to take it all in. 

As I took in the soundscape I was listening for Mondon monoceros (narwhals), trying to understand just how far north they may have been herded by the increasing ship noise in the Arctic (narwhals are incredibly sensitive to sound). I wondered how far they had to go in search of food in the rapidly transforming Arctic food web. I questioned just how much ocean warming they could endure. 

This North Pole playlist is evolving as I review the data. These sounds offer us a snapshot of life below North Pole sea ice as the ice thins and acquiesces to a disastrously warming Arctic … sighing at the sight of way too many melt ponds.