Thread: Oxygen cycle?

Does anyone have a vague idea how many years does it take for half of free oxygen in the atmosphere to be recycled. For example if you had a giant hypothetical disaster that burned or converted to dioxide half the earths atmosphere, how many years would it take to the various oxygen producing lifeforms and various other chemical interactions to bring back that level of oxygen?

Do all oxygen breathing organisms, forest fires, and oxydation and combustion of various types, collectively consume 1% of the earth atmosphere's oxygen in a year or is it more like 0.000001%

Where does it mostly come from anyways, forests, grass, algue, bacteria/unicellular, gysers/eruption?


I heard somewhere that the earth's atmosphere may have had much higher oxygen concentration at the time when dinosaurs walked the earth, I dont know it thats true or not.

Originally Posted by icewendigo

I heard somewhere that the earth's atmosphere may have had much higher oxygen concentration at the time when dinosaurs walked the earth, I dont know it thats true or not.

Probably so because at Oxygen level much higher than now forest become much more combustive and prone to catastrophic fires.

if you had a giant hypothetical disaster that burned or converted to dioxide half the earths atmosphere

Sorry to be pedantic but four fifths of the earth's atmosphere is nitrogen and argon so it's impossible for half the atmosphere to be converted to dioxide. Nitrogen won't oxidize below a couple of thousand degrees and argon not at all.

If half the oxygen were converted to CO2 I would imagine the greenhouse effect would boil the oceans. Oxygen producers that worked here previously would most likely not exist in those conditions. I think your question is a little too hypothetical for anything but speculation.