When fertile waters meet desertic lands

A huge phytoplankton patch was produced by the upwelling mechanism along the west coast of Africa near Mauritania.

In upwelling areas, deep water is pumped up to the surface by strong winds. This deep water is rich in nutrients supplying phytoplankton which in turn supports the whole food chain.

Coastal upwelling generates fertile ocean coasts and important fishing grounds. However, it also creates a cool and stable coastal atmosphere with very low rainfall, forming some of the driest deserts on Earth.

Question: Why study ocean currents from space ?