Exercise 3 solution (model answer)

A northerly wind blows toward the south, along the coast, which lies on the left of the wind (the coast is to the east). In the northern hemisphere the net Ekman transport is 90 degrees to the right of the wind direction, that is to the west, away from the coast. The surface water is therefore moved offshore, and deeper water rises along the coast to take its place. That deeper water is cold and rich in nitrate and phosphate that has built up from decaying sinking material. In the sunlit surface layer, these nutrients allow phytoplankton to multiply, which supports zooplankton, fish and the larger animals that feed on them. This is why the California coast has cool summers and productive waters.