Many of the chemical elements are constantly taken up, excreted and/or transformed by living organisms. This is true for those elements that constitute a significant part of the biomass on Earth (carbon, nitrogen, sulfur and phosphorus) as well as for many other elements present in small amounts in living cells, such as iron and many other metals. The biogeochemical cycles qualitatively and quantitatively describe the cycling of the elements between the abiotic terrestrial, marine and atmospheric environment and the biota.
Keywords: biogeochemistry; element cycles; primary production; degradation; dissimilatory processes







