This is total nonsense. If plants were converting oxygen from water at such a rate, the seas would be dropping constantly and would have almost dissappeared by now. Truth of the matter is that the earth is a very well balanced eco-system and has been so for as far back as we can tell.
-- gore300
This is such a staggeringly ridiculous strawman model of anything going on in the real world, I just wanted to blow it up a little bigger as a monument to Cretin Science.
When you do photosynthesis, sunlight in the presence of the catalyst chlorophyll energizes water and carbon dioxide to form glucose and free oxygen. (More complex carbos can form in other reactions with the glucose later but this is the step that consumes a little water.)
When you burn/metabolize the glucose (or any carbohydrate) with free oxygen you get the water and carbon dioxide back. You also get some of the solar energy that was stored chemically in the glucose.
The only water not returned to the system is the water and carbohydrate content of the biomass itself. Period. The only way for the ocean to dry up from bioactivity was for the ocean to turn completely into sugar, starch, cellulose, etc. There probably are a lot of limiting factors that put you in equilibrium before that happens. (Not enough carbon or other essential elements, etc.)
How helpful you are! I thought you were disagreeing with me! Instead, you are disagreeing with yourself! You keep giving more and more proof that your statement in post#673 is totally ridiculous - just as I said!:
"We can be sure that there was little oxygen in the atmosphere on earth until life got started, notwithstanding all the lightning."-vade retro-
Thanks again!