BioGeoChemical Cycles

A biogeochemical cycle is the complete pathway that a chemical element follows through the Earth system—from the atmosphere, waters, rocks, or soils, to living organisms and back to the atmosphere, ocean, soils, or to other organisms.

They are chemical cycles because chemical elements are the form that we consider;

 they are bio- because these are the cycles that involve life;

 they are geo- because these cycles include atmosphere, water, rocks, and soils.

These cycles are driven directly or indirectly by incoming solar energy and gravity. For complete recycling of chemical elements to take place, several species (producer, consumer, and decomposer) must interact.

Major BioGeoChemical Cycles

 Here we consider the global cycles of carbon, nitrogen, and phosphorus in part because they are the three of the “Big Six”(C, H, O, N, P, S) —the elements that are the basic building blocks of life. But each also poses important environmental issues.