The rapidly growing field of submesoscale ocean dynamics refers to the study of turbulent structures at a scale of motion smaller than the regular (mesoscale) ocean eddy field. Their tiny scale makes submesoscale features difficult to observe and expensive to model, although studies in the past ten years have demonstrated that submesoscale features can be very intense near the surface of the ocean.
The innovative aspect of Gula et al.  is that they show that strong submesoscale motion can also be found in the ocean interior, in the form of tiny intense vortices that are approximately 200 meters deep and about 10 kilometers wide. Similar vortices are found both in observations and in a high-resolution regional model, implying that the formation of the vortices is a robust dynamical feature. The vortices are generated by the interaction of the Gulf Stream with topography, and particularly with the Charleston Bump. The implications of these findings are that deep ocean submesoscale structures may be more common than previously thought, and therefore may play a key role in balancing the ocean energy budget.
Citation: Gula, J., Blacic, T. M., & Todd, R. E. . Submesoscale coherent vortices in the Gulf Stream. Geophysical Research Letters, 46. https://doi.org/10.1029/2019GL081919
—Andrew M. Hogg, Editor, Geophysical Research Letters