Millions of seafloor pits, not pockmarks, induced by vertebrates in the North Sea

This study challenges the traditional interpretation of seabed pockmarks as surface manifestations of hydrocarbon fluid venting. Using high-resolution multibeam echosounder data in the North Sea, the researchers documented over 40,000 shallow depressions, termed 'pits', with unique morphologies unlike known pockmarks. By integrating data from behavioral biology, oceanography, remote sensing, and habitat mapping, they propose that harbor porpoises create these pits during benthic foraging. The porpoises' grubbing action dislodges sandeels, initiating pit formation, which then evolve through scouring and merging. This megafauna-driven macro-bioturbation significantly reshapes the seafloor, influencing sediment transport and ecosystem dynamics.

Jens Schneider von Deimling, Jasper Hoffmann, Jacob Geersen, Sven Koschinski, Arne Lohrberg, Anita Gilles, Igor Belkin, Christoph Böttner, Svenja Papenmeier, Sebastian Krastel