Upwelling currents bring deeper, colder water to the surface. Whereas surface waters are usually depleted of nutrients such as phosphates and nitrates that are critical to plant growth, deeper waters have high concentrations of these nutrients. Upwelling replenishes the surface layers with the nutritional components necessary for biological productivity. Regions of upwelling are among the richest biological areas of the world. Satellites orbiting the earth can measure chlorophyll pigment and water temperature.
False color is added to highlight different concentration values and different ocean temperatures.