oxygen cycle

American  

noun

Ecology.

1. the process by which oxygen released 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.

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Etymology

Origin of oxygen cycle

First recorded in 1930–35

Example Sentences

The challenge now, he says, is assessing “the relative importance of this process versus the other things we know about the global oxygen cycle.”

From Scientific American

“There’s a lot we don’t know about the oxygen cycle on Mars. That’s become apparent.”

From New York Times

The former endangers health, and many ecologists say that increased carbon dioxide threatens the earth's oxygen cycle.

From Time Magazine Archive

He could listen to his own lungs and pulse, loud in the spacesuit; he could even notice its interior smell, blend of plastic and oxygen cycle chemicals, flesh and sweat.

From Project Gutenberg