The Oxygen Cycle
Kevin Kwong and John Solder
9.6 x10^9 kg
1.4 x10^18 kg
2.9 x10^20 kg
1.6 x10^16 kg
Modified from http://ilc.royalsaskmuseum.ca/ilc6/pages/62b/63e/pf63ep2p1.htm
Fluxes and Residence
ReservoirCapacity (kg O2)
(1020)
Flux In/Out (kg O2/year)
(1010)
Residence Time (years)
Atmosphere0.014 30,000 4,500
Biosphere 0.00016 30,000 50
Lithosphere2.9 60 5*10 8
Hydrosphere.00000000096 450 21 *10 6
Hydrosphere Calculation
Sea-Surface Dissolved Oxygen (0~600 m) 5.4 x 10^16 mol
Anoxic Zone (600~1100 m) Very Low DO
Deep Ocean (1100~4000 m) 2.08 x 10^20 mol
X 32 g/mol => 6.65 x10^18 kg O2
Photosynthesis and Respiration
6CO2 + 6H2O + Energy → C6H12O6 + 6O2
C6H12O6 + 6O2 →6 CO2 + 6H2O + Energy
686 Kcal is the amount of energy imputed and released from these systems
Photodissociation
Breakdown of Ozone by Photons.
O3 + hν → O2 + O
@ λ ~240-310 nm
O3 + O → 2 O2
2 O → O2
The overall amount of ozone in the stratosphere is determined by a balance between production by solar radiation, and removal. The removal rate is slow, since the concentration of O atoms is very low.
Weatheringand Deposition
Oxidation of Earth Materials.
4FeO + O2 → 2Fe2O3
2 Ni + O2 = 2 NiO
2 Fe + SiO2 + O2 = Fe2SiO4
Biological Weathering releases O2 from minerals as other nutrients are consumed.
(Chelate compounds)
Corals and shells of marine organisms are O rich (CaCO3), becomes limestone.