Upwelling
The major upwellings in the ocean are associated with the divergence of currents that bring deeper, colder, nutrient rich waters to the surface. There are at least five types of upwelling: coastal upwelling, large-scale wind-driven upwelling in the ocean interior, upwelling associated with eddies, topographically-associated upwelling, and broad-diffusive upwelling in the ocean interior.
Patagonia
The Patagonian freshwater fish fauna is relatively restricted compared to other similar Southern Hemisphere regions. The Argentine part is home to a total of 29 freshwater fish species; 18 of which are native. The introduced are several species of trout, common carp and various species that originated in more northerly parts of South American. The natives are osmeriforms ("Aplochiton" and "Galaxias"), temperate perches ("Percichthys"), catfish ("Diplomystes", "Hatcheria" and "Trichomycterus"), Neotropical silversides ("Odontesthes") and characiforms ("Astyanax", "Cheirodon", "Gymnocharacinus" and "Oligosarcus"). Other Patagonian freshwater fauna include the highly unusual aeglid crustacean.