What is the definition of the oxygen cycle?

The oxygen cycle is the biogeochemical cycle of oxygen within its three main reservoirs: the atmosphere (air), the total content of biological matter within the biosphere (the global sum of all ecosystems), and the Earth's crust.

The process by which oxygenreleased into the atmosphere by photosynthetic organisms is taken up by aerobic organisms while the carbon dioxide released as a by-product of repiration is taken up for photosynthesis. Origin ofoxygen cycle Expand.