Currents and winds reverse and now bring warm water and air from the western Pacific to the Galapagos and coastal South America. Areas in northern Australia, New Guinea, and Indonesia suffer drought while heavy rains occur in the Galapagos and the west coast of South America. In the Galapagos, the rains moisten even the dry lowlands, allowing vegetation to flourish. With food abundant, the terrestrial animals, such as the iguanas and finches, do well. At the same time, these changes inhibit the upwelling that enriches the Galapagos waters in nutrients.
Sea life suffers as a result, sometimes dramatically.
A particularly severe El Ni o occurred in 1982-1983. But it was a catastrophy for marine life. Sea birds of all types were unable to raise their young and there was high mortality among marine iguanas and fur seals. El Ni o thus sets a rhythm to Galapagos life, but one in which the fortunes of marine and terrestrial life are exactly out of phase. El Ni o has been one of the strongest events of the century.