Is the biogeochemical cycle by which
carbón is exchanged among the biosphere,
pedosphere,geosphere,hydrosphere, and
atmosphere of the Earth.
The main ways that carbón gets into the carbón cycle are volcanoes.
The store of carbón in sedimentary rock is far greater than
the CO2 in the atmosphere. Eventually it retutns to the air
as oceanic plates subduct in plate tectonics, At the margins
of plate boundaries volcanoes form and spew out CO2.
Nitrogen cycle
The natural circulation of
nitrogen by living organisms.
Nitrates in the soil, derived from
dead organic matter by bacerial
action,are absorbed and
synthesized into complex organic
compounds by plants and
reduced to nitrates again when
the plants and the animals
feeding on them die and decay.
without the nitrogen cycle, we would be unable to breathe the air around us
beacause the nitrogen would remain in its unconverted state.