In the flow of energy through the ecosystem, energy is lost at each trophic level. Some of this loss is due to metabolic needs, such as moving, and some is due to the formation of inedible tissue such as shells.
Nutrients are chemical elements and compounds that are necessary for life.
The flow of nutrients such as carbon, oxygen, nitrogen, or phosphorus is called biogeochemical cycling . Decomposers play a key role in the biogeochemical cycles by returning nutrients to the soil, water, or air. You can download an Adobe Acrobat Reader version of the cards by clicking here . You'll need to make several copies of the phytoplankton, Copepod and Herring cards. Review the concepts of food web and energy flow with your class.