Question

Why are the processes that move water, carbon, and nitrogen around an ecosystem considered cycles?

In your answer, explain how this is different from the way energy flows through an ecosystem.

Answer 1

Energy flows through an ecosystem and is dissipated as heat, but chemical elements are recycled. The ways in which an element—or compound such as water—moves between its various living and nonliving forms and locations in the biosphere is called a biogeochemical cycle.