El Niño can have a big impact on the littlest plants in the ocean, and NASA scientists are studying the relationship between the two. In El Niño years, huge masses of warm water splash east across the Pacific Ocean towards South America. While this warm water changes storm systems in the atmosphere, it also has an impact below the ocean’s surface. These impacts, which researchers can see with satellite data, can mess up the food chain to fish and fishermen. El Niño’s mass of warm water puts a lid on the normal currents of cold, deep water that typically rise to the surface along the equator and off the coast of Chile and Peru. In a process called upwelling, those cold waters normally bring up the nutrients that feed the tiny organisms, which form the base of the food chain.These tiny plants, called phytoplankton, are fish food – without them, fish populations drop, and the fishing industries that many coastal regions depend on can collapse.