Physical oceanography during G. O. Sars cruise GS2018108 to an Arctic deep-sea sponge ground in 2018

Internal waves supported by vertical density stratification interact with the seamount topography and produce turbulent mixing as well as resuspension of organic matter with temporarily very high current speeds up to 0.72 m s-1. The vertical movement of the water column delivers food and nutrients from water layers above and below towards the sponge ground. Highest organic carbon flux was observed during the summer phytoplankton bloom period, providing fresh organic matter from the surface.

The flux of fresh organic matter is unlikely to sustain the carbon demand of this ecosystem. Therefore, the availability of bacteria, nutrients and dissolved and particulate matter, delivered by tidally-forced internal wave turbulence and transport by horizontal mean flows, likely plays an important role in meeting ecosystem-level food requirements.