Definition - What does Phytoplankton mean?
Phytoplankton are the photosynthetic organisms in plankton and mostly consist of single-celled algae and cyanobacteria, which is bacteria that is chemically diverse and produce oxygen through photosynthesis. These plankton are similar to land-based plant organisms in that they need sunlight and inorganic nutrients like nitrates, phosphates and sulphur, which they turn into proteins, fats and carbohydrates in order to survive, and contain chlorophyll.
Safeopedia explains Phytoplankton
Phytoplankton play an important part in our ecosystem, providing food for a large variety of sea creatures including whales, shrimp, jellyfish and snails. In addition, their photosynthesis allows them to fix a large amount of carbon and produce breathable oxygen. When there are too many nutrients, phytoplankton can grow out of control and form harmful algal blooms (HAB) or a 'red tide,' which can be very toxic to humans and animals.