The connected ocean: the global-scale transports of heat, nutrients, plankton and plastic by ocean currents

The global ocean is in constant motion, with water circulating within and flowing between basins. As the water moves around, it carries heat and nutrients, as well as planktonic organisms and plastic litter around the globe.

The most natural way to study the pathways of water and the connections between ocean basins is using particle trajectories, in the so-called Lagrangian framework. The particle trajectories can come from either observations of GPS-equipped drifters in the real ocean, or from simulations of virtual particles in high-resolution ocean models.

Here, I will give an overview of some recent work with these Lagrangian particles to map and understand the connectivity of the global scale ocean. I will show applications to marine microbiology and ecology, palaeoclimatology and plastic pollution. I will discuss the policy implications of this trans-national flow of material and how regional connectivity maps can be used in Marine Spatial Planning. Central to each of these examples is the question on how connected the different ocean basins are, and on what time scales water flows between the different regions of the ocean.