Organisms that float are like the grass of the sea. Grass provides food for things that live on land, and on each other. Drifting sea grass drifts in pelagic zones of the sea, thick in some parts and thin in others. Fish and other sea creatures thrive on it. Plankton – what is plankton – science tells us that it is the best fish food.
The countless billions of individual organisms that drift in the sea vary in size from huge drifting jellyfish to creatures that are so small that they can only be discerned by electron microscopes. They were identified by the 1980s.
Seasonally the minute organisms appear to become more prolific, and almost burst into flower. These times are known as the Spring bloom of ocean areas. Sea organisms are so prolific that they are not described individually, but generally as if they do not have species identity, though in theory taxonomic identification should be possible.
Plant forms are called phytoplankton and animals are known as zooplankton. The latter feed on the former and tend to be swept into the same parts of seas and lakes. The Spring bloom will therefore be made up of both plants and animal species. Other aquatic life forms, even including massive whales, follow the flow and are most prolific where the the organisms are thick.
Ocean currents sweep different concentrations into different parts of the sea. Fish follow the food supply. Although some zooplankton have slight powers of movement they cannot really determine where they drift. Ocean currents sweep them into different concentrations in different parts of the sea. Since there are consistent seasonal movements in currents it is possible to predict where the fish food concentrations will be, and consequently the fish that feed on them.
Seas that lie adjacent to deserts like the Namib on the West African coast are often very rich in aquatic life. This is probably because winds blow fertile dust from the deserts onto the surface of adjacent seas. It sinks to the bottom, and is then returned to higher zones as soup upon which pilchards and other fish feed.
The field of study related to plankton offers some amazing opportunities for increased health and well being. Researchers studying marine phytoplankton are just starting to tap into this plethora of possibilities.