Multi-Scale Flows and Pathways in the Gulf of Mexico and South China Sea: implications of ocean submesoscale turbulence for oil dispersion, coral evolution and carbon uptake*

In the ocean forcing acts at planetary scales and dissipation at microscales. In between there are the mesoscales, with characteristics akin to nearly two-dimensional, quasi-geostrophically, balanced turbulence. The dynamical structures typical of the mesoscales are eddies and fronts. They extend from few tens to hundred of kilometers, and act as weather systems of the ocean.
At the ocean boundary layers, near the surface and at the bottom, unbalanced, submesoscale flow structures may appear in the form of vorticity filaments, density fronts or coherent vortices, with typical scales of hundreds of meters to few kilometers and a lifespan of several hours to few days. These submesoscale circulations provide a pathway for energy transfer towards smaller scales, are likely to contribute to the overall overturning budget, and impact lateral and diapycnal mixing.
Here I present an overview of recent studies of physical and biogeochemical interactions across mesoscale and submesoscale flows focusing on the Gulf of Mexico and South China Sea. I will describe the physical mechanisms responsible for the patterns of oil dispersion at the ocean surface and near the bottom using models and observations from the aftermath of the 2010 Deepwater Horizon oil spill, and will provide examples of how mesoscale and submesoscale circulations impact the dispersion of tracers, from carbon to cold-water coral larvae.