biogeochemical cycle

This term refers to the cycle of living or "biological " matter as it circulates through geological (geo) environments to form an ecosystem. A forest, for example, is an ecosystem made up of plants and animals that rely on elements in soil and water to live. The process of exchange between the living (the trees) and the non-living (the soil)--through a series of chemical reactions at the cellular level--is called a biogeochemical cycle.