A biogeochemical cycle describes a pathway by which a chemical substance (oxygen, carbon, nitrogen) moves through both biotic and abiotic compartments of Earth. Elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere or geosphere to another through biogeochemical cycles. The term "biogeochemical" tells us that biological, geological and chemical factors are all involved. The circulation of essential nutrients like carbon, oxygen, nitrogen, phosphorus, calcium, iron and water etc. through the biological and physical world are known as biogeochemical cycles.