Numerous organisms in the sea consume plankton, including all baleen whales like blue whales and bowhead whales, fish like whale sharks and other filter-feeders. Plankton have long been attributed as the foundation of the ocean food web, and can be separated into two distinct and different groups: phytoplankton and zooplankton. Both have contributed immensely to the ecosystem by harvesting energy through photosynthesis and converting it into essential nutrients.
These microscopic marine plants and animals are motile, whether they have cilia that help propel them through the water or whether they rely on the ocean currents to move them along. They are responsible for producing up to 90 percent of the world's oxygen supply as well.