Atmosphere: Around 21 percent of the oxygen by volume is present as free oxygen. Other oxygen-containing molecules include ozone, water vapors, carbon dioxide, oxides of sulfur and nitrogen.
Biosphere: Around 22 percent of the oxygen by volume is present as the composition of organic matter and water molecules.
Hydrosphere: Around 33 percent of the oxygen by volume is present in the hydrosphere. It is present in the form of dissolved oxygen, components of water molecules and carbonic acids.
Lithosphere: Around 47 percent of the oxygen by volume is present as oxide minerals such as silica minerals et cetera.
