The Blue Machine

At the ocean surface, the wind drives water westwards, out into the Pacific Ocean. All along this coastline, the warm surface layer is constantly pushed offshore, and the push is so strong that the warm water moves away from the coastline entirely. You might think that would leave a hole, but down below the anchoveta, at a depth of about 300 metres, water from the ocean’s cool lower layer moves in to fill the gap, drifting eastward until it meets the coast and then moving upwards. Our anchoveta is swimming around in sunlit water from the deep ocean. Literal-minded ocean scientists call this upward flow an upwelling. Cold, nutrient-rich water has escaped from underneath the warm lid, and as it comes up to meet the sunshine, all the ingredients for life are there in huge quantities. It doesn’t happen along every coastline, but it happens here in style. The phytoplankton can gorge themselves silly on sunlight, stashing away solar energy on a monumental scale.