Contrasts to land, waters in this area are parts of the Canary Current System, a highly productive ocean current and the Nouadhibou Upwelling, one of major upwelling zones locates just off the continent shelf.
Upwelling at the equator is associated with the Intertropical Convergence Zone (ITCZ) which actually moves, and consequently, is often located just north or south of the equator.
Other arid regions include areas located in the rain shadows of major mountain ranges or along coastal regions affected by significant upwelling (such as the Atacama Desert).
Gale winds and the Earth's rotation drive surface water away from the shore, only to be replaced by an upwelling of colorer, deeper, and more nutrient-rich waters from offshore.
Its middle and upper Miocene upwelling-rich assemblages, and its unique highly siliceous rocks from diatom-rich plankton, became diatomites, porcelainites, and banded cherts.
Downwellings are common in Hecate Strait and Queen Charlotte Sound, especially in winter, but there is an occasional summer upwelling5.
Mantle plume, or volcanic plume, an upwelling of abnormally hot rock within the Earth's mantle, which can cause volcanic hotspots