ICSE Class 7 Answered

The Peru current is a cold current which originates in the Atlantic ocean. As it strikes the west coast of South America, the waters of the islands supports the growth of planktons. Planktons are microorganisms which form the food of the fishes. Anchovy is one of the most important varieties of fish which feeds on the planktons. It in turn becomes the food of sea birds. Sea birds in large numbers flock to this island in search of the food. The droppings of these fishes then get preserved in the hot and dry climate and turn into deposits of nitrates.