In oceans or larger lakes, a water current, or movement of surface water produced by wind and a resulting Ekman spiral, which brings colder water, loaded with nutrient, to the surface from a lower depth. Ocean upwellings occur off Peru, California, W. Africa, and Namibia, and increase the nutrient content of the surface waters, leading to an abundance of marine and bird life. Upwelling also occurs in the open oceans where surface currents diverge, as deep waters rise to the surface to replace the departing waters, and all along the equator as a result of the effects of the NE and SE trade winds.