Oyashio and Kuroshio Currents

In the Pacific Ocean, near Hokkaido, Japan the colder Oyashio Current converges from the north with the warmer Kuroshio Current, which flows from the south. When two currents with different temperatures and densities collide, they often create eddies – swirls of water drifting along the edge of the two water masses. The phytoplankton growing atop the surface waters become concentrated along the boundaries of these eddies and trace out the motions of the water.