The main difference between zooplankton and phytoplankton is that phytoplankton has the ability to manufacture its own food through photosynthesis or chemosynthesis. Zooplanktons are incapable of making their own food. Zooplanktons are animal planktons,while phytoplanktons are planktons that are capable of carrying out photosynthesis.
Planktons are generally referred to as “floaters,” organisms that drift in aquatic environments. They are broadly divided into two groups: zooplankton and phytoplankton. Both groups are identified by their ecological niche at the base of the food chain. Most of the planktons (phytoplankton and zooplankton) are single-celled organisms. Phytoplanktons are the bottom-level producers of the ocean, while zooplanktons are the bottom-level consumers of the ocean. Phytoplanktons also play an important role on land. They produce more than 50 percent of Earth’s oxygen supply.
Phytoplanktons are found in regions which have the kind of energy needed for photosynthesis or chemosynthesis. This constrains them to the photic zone, the region of the ocean where light can penetrate, and to undersea openings. Zooplanktons are not limited to an external nonorganic source of energy. Unlike the phytoplanktons, which are limited to a depth of about 800 feet, zooplanktons have no depth limits, but they have to be around a source of food.