The word plankton comes from the Greek word meaning "wanderer". It refers to the diverse group of plants and animals that spend part or all of their life cycle drifting in the water of oceans or freshwater lakes. Plankton is abundant and important in the marine environment. Most of Earth's biomass, the mass of living organisms, is plankton drifting in the oceans. Ninety-eight percent of marine species live on the seabed, but the vast majority of ocean biomass is planktonic. Many of these organisms are capable of locomotion, but are generally unable to move independently of currents and waves. This lack of strong swimming ability separates plankton from nekton, which includes organisms that can control their own movement in the water. Some planktonic organisms can be quite large, however plankton is generally smaller than nekton. Plankton can be classified based on their feeding style. Phytoplankton is a very important part of ocean life. Carbon dioxide in the atmosphere is in equilibrium with carbon dioxide in the ocean. During photosynthesis, phyto...