Planktonia: The Nightly Migration of the Ocean's Smallest Creatures

When discussing "migration," the focus typically shifts to animals transitioning between feeding and breeding areas annually. However, the most significant migration on Earth occurs twice nightly, involving a vertical movement orchestrated primarily by plankton, which are then hunted by various predatory marine species like fish, squid, and octopus. This phenomenon initiates at sunset, with plankton rising from deep ocean waters, where they feast on plant plankton and other small organisms, including some of their own kind. Their feeding cycle concludes just before dawn, prompting a retreat back to the ocean depths to evade predators during daylight until the migration resumes the following evening.