Plankton are passive drifters that are unable to swim against the current and are suspended in the water column. Some (phytoplankton) are photosynthetic and produce nearly half of the world’s oxygen and some (zooplankton) are tiny animals or protists that feed on the phytoplankton and other tiny food particles. Small planktonic organisms form the basis of food webs whose energy flow supports larger organisms like apex predators. Plankton are beautiful organisms to image with the microscope and they’re important for maintaining balance in aquatic ecosystems.