Churning of the seafloor: On-going growth and collapse of ice cored submarine pingos

A multipronged, 12-year study has revealed a complex, submarine morphology dotted with pingos which are continually changing due to ongoing freezing and thawing of brackish groundwater seeping up from buried ancient permafrost. Multibeam mapping surveys on both sides of the Mackenzie Trough in the Canadian Beaufort Sea were repeated in 2025, 8 and 12 years after the initial mapping surveys. Differencing 1-m-scale bathymetry grids collected using Autonomous Underwater Vehicles reveals the tops of pingos experience up to 1.5 m of upwards growth between surveys, documenting of upwards growth approaching 20 cm per year of submarine pingos for the first time. Up to 5 m of down drops were also observed on the crest of some submarine pingos. Areas that experience 1.5 m of growth are less than 10 m from areas that experienced 2.0 m of down drops. Remotely Operated Vehicle (ROV) based low altitude surveys using stereo cameras, multibeam, a laser scanner, and vision-based Simultaneous Localization and Mapping navigation mapped sections of this dynamic morphology at sub-cm resolution providing extraordinary detail on the on-going seafloor deformation associated with submarine permafrost. An ice layer exposed in the wall of an