Ridges, Seamounts, Troughs, and Bowls: Topographic Control of the Dianeutral Circulation in the Abyssal Ocean

What is it about?

Turbulent mixing plays a crucial role for the abyssal ocean circulation by converting dense waters into lighter waters and maintaining the abyssal stratification. However, in-situ observations have shown that the intensity of turbulent mixing is enhanced toward the seafloor, implying that interior waters are generally made denser. Thus a new paradigm has emerged where the upwelling of dense waters into lighter waters occurs only within the bottom boundary layer. Here we show that this implies that upwelling can depend on subtle features of the seafloor geometry. Small changes in the circumference and curvature of the seafloor can influence the abyssal stratification, and drive lateral exchanges between the boundary layer and interior. These results add to a growing body of literature highlighting the key control of seafloor geometry on the abyssal overturning circulation.

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