Phtoplankton is a free- floating, wandering type of plant that is generally found in the water. It is a component of the planktom community. Most photoplankton are too small to be able to be seen with the human eye alone unless there are incredibly large numbers of it floating together. If this occurrs, a human will typically see photoplankton as greenish in color. This is nominally due to the effects of photosynthesis.