An antarctic marine food web.

The producers in this food web are phytoplankton.

Zooplankton comprising krill and copepods serve as primary consumers, which in turn are fed upon by consumers of higher trophic levels

Most communities exhibit complex trophic interactions, and its organisms form a branching food web.

Some consumers may have two-way trophic relationships with other organisms: some fish feed on squids, while some squids feed on fish; these may be the same 2 species at different stages in their life cycle.

Food web exercise: