About Oceans

 Mostly from here.

Some physical consequences have vast biological effects. Nutrients, as well as oxygen, are in short supply in the Ocean. Deep waters accumulate such nutrients from organisms living near the surface and sinking after death. In certain regions, currents bring these deep waters up to the surface, cooling surface waters and enriching them with nutrients, which favour the growth of phytoplankton. 

This is called upwelling, and the end result is a much richer food chain: approximately 40% of the total global fish catches comes from four upwelling areas, which occupy only 3% of the total ocean area: the Humboldt current, off Peru and Chile, the California current, the Canary current, off Northwest Africa, and the Benguela current, off Southwest Africa. 

Plastics globally (A lot of plastic finds its way to oceans)