What defines a biogeochemical cycle?

A biogeochemical cycle is defined by the movement of elements between living organisms and their environment. This concept encompasses the pathways through which essential elements such as carbon, nitrogen, phosphorus, and water circulate through both biotic (living) and abiotic (nonliving) parts of ecosystems.

In these cycles, elements are transformed and reused in various forms; for instance, carbon is absorbed by plants during photosynthesis, consumed by animals, and eventually returned to the atmosphere through respiration and decomposition. This continuous movement and transformation ensure that vital nutrients are available for all forms of life, supporting the health and stability of ecosystems.

While interactions between living and nonliving components are important, they are broader and do not specifically characterize the cycle of elements. Seasonal changes can influence these cycles but do not define them. Energy transfer is a different concept, primarily focusing on how energy flows through food webs rather than the cycling of elements, which is distinct and more about material recycling in the environment. Thus, the precise definition of a biogeochemical cycle is the movement of elements and nutrients between the biosphere and the Earth's various environments.