Upwelling refers to an oceanographic phenomenon characterized by wind-induced movement of ocean water so that the deep and cooler water moves to the ocean surface and replaces the less dense and warmer ocean water. The dense and cold water constitutes abundant nutrients while the warmer water is nutrient-depleted.
One of the major causes of upwelling is the blowing of wind along a coastline. When wind blows parallel to a cost, it causes the water at the ocean surface to move perpendicularly and away from the cost. This occurs due to a phenomenon called Ekman transport and deflections resulting from Coriolis Effect (Ernst 167). The movement of the surface water creates an imbalance that forces the dense and cooler water to rise up and introduce equilibrium. Another cause of upwelling is the El Nino phenomenon in the Pacific Ocean. The movement of surface wind causes irregular shifting of pressure areas in the western and eastern Pacific. The associated trade winds cause the movement of surface water on either sides of the equator and changes to upwelling. The third cause of upwelling is the influence resulting from the bottom topography of the ocean floor. Research indicates that areas characterized by steeply sloped ocean floor have a high probability of experiencing more upwelling in comparison to areas with gently sloped ocean floor. Depending on the ocean topography, movement of ocean currents may cause the subsurface water to move to the ocean surface (Conway 214).
There are six major areas of upwelling. The first is the West coast of North America in which upwelling results from the Californian Current. The second area is the Oregon costs. The third region of upwelling is the Peru cost in which upwelling results from to the Peru Current (“Investigating the Ocean - Ocean Upwelling”). The fourth and fifth regions of upwelling are the West coast of North Africa and South Africa due to the effects of Canaries Current and the Benguela Current respectively. The last region of upwelling is the Pacific Ocean characterized by equatorial upwelling.