biogeochemical cycles

Self-regulating

Systems that can adjust and maintain themselves without external influence

Sources and sinks (reservoir)

Points where substances enter or leave a system

Water Cycle

Movement of water in its various forms on Earth

Carbon Cycle

Circulation of carbon through the atmosphere, oceans, soil, and living organisms

Nitrogen Cycle

Process by which nitrogen is converted between its various chemical forms

Phosphorus Cycle

Movement of phosphorus through the lithosphere, hydrosphere, and biosphere