Editing Upwelling (section)

==High productivity==

The most productive and fertile ocean areas, upwelling regions are important sources of marine productivity. They attract hundreds of species throughout the trophic levels; these systems' diversity has been a focal point for [[marine research]]. While studying the trophic levels and patterns typical of upwelling regions, researchers have discovered that upwelling systems exhibit a wasp-waist richness pattern.  In this type of pattern, the high and low [[trophic level]]s are well-represented by high species diversity.  However, the intermediate trophic level is only represented by one or two species.  This trophic layer, which consists of small, [[pelagic fish]] usually makes up about only three to four percent of the species diversity of all fish species present.  The lower trophic layers are very well-represented with about 500 species of [[copepods]], 2500 species of [[gastropods]], and 2500 species of [[crustaceans]] on average.  At the apex and near-apex trophic levels, there are usually about 100 species of marine mammals and about 50 species of marine birds.  The vital intermediate trophic species however are small pelagic fish that usually feed on [[phytoplankton]].  In most upwelling systems, these species are either anchovies or sardines, and usually only one is present, although two or three species may be present occasionally.  These fish are an important food source for predators, such as large pelagic fish, marine mammals, and marine birds.  Although they are not at the base of the trophic pyramid, they are the vital species that connect the entire marine ecosystem and keep the productivity of upwelling zones so high<ref name="Cury"/>