Density Staircases Are Disappearing in the Canada Basin of the Arctic Ocean

In the Canada Basin of Arctic Ocean, warm and salty Atlantic-origin Water (AW) lies in intermediate layer (250 m–800 m) below a colder fresher surface layer. It results depth range where vertical thermohaline gradients are propitious to double-diffusion. Indeed, staircases commonly observed associated with double-diffusive processes. Using observations from Beaufort Gyre Exploration Project large database Ice-Tethered Profilers, we document presence density 300 m–700 m striking strong spatial temporal coherence. However, since 2007, progressive smoothing these has occurred, beginning western half basin. Quantifying this evolution, find that general pattern is clear evolution over time numerous thick steps ( ≃ 40 sharp interfaces fewer thinner 30 smoother interfaces. After 2014, marked have almost disappeared most Basin. The vanishing occurs few years coincides modifications scale circulation horizontal gradients. As small structures thought play an important role for exchanges heat within Basin, disappearance may impact distribution at depth, potential consequences sea ice cover.