The greatest migration on Earth doesn’t take place on land. It happens in the Ocean, and it happens every day, driven by the movement of zooplankton toward the surface; this movement influences many animals throughout the Ocean’s layers. According to NOAA, scientists call this process diel vertical migration, and they believe it is primarily driven by light. The abundance of food and predators, as well as temperature, plays a factor. Excessive light—or irradiance, the density of radiation on a s