Flowing
For the most part, plankton move by flowing with water currents.

Autotrophic
An autotrophic organism does not require food. Instead, it can produce its own energy by using sunlight to photosynthesize. Producers are autotrophic.

Eutrophication
The drastic increase in the amount of producers (such as algae and cyanobacteria) that is caused by the increase in the amount of nutrients (especially nitrogen and phosphorous) in the water. 

Asexual reproduction
Reproduction without fertilization, for example by dividing. The offspring that are produced asexually are genetically identical to the parent. Asexual reproduction is the simplest and fastest method of reproduction for living organisms. 

Sexual reproduction
Reproduction with the use of gametes or sex cells. Sexual reproduction increases the genetic diversity of the individual. 

Heterotrophic
An organism that receives its energy by consuming other living or dead organisms. Consumers and decomposers are both heterotrophic.