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

Autotrophic
An autotrophic organism does not require food. Instead, it can produce its own energy by using sunlight to photosynthesize. All 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 a water ecosystem. 

Asexual reproduction
Reproduction without fertilization, for example by division. Offspring that are produced asexually are genetically identical to their 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.