Thanks for the link. I see registration is required to read the article, which at this point I’m declining to do… I appreciate your taking the time to reply, though!

Thanks again, Mith… that’s a pretty heavy load, I agree. I was just wondering how long it would last if there were no plants to resupply the oxygen, and if there were any bacteria that do and would contribute to the oxygen supply.

I’d sort of kind of figured that might be the case. But what, then, would happen if all that algae were gone? Would the existing 20% oxygen in the earth simply remain as it is in the atmosphere? If, say, a million humans survived to try and re-populate the planet, how long would it take them to use up that 20% (leaving aside for the moment the question of where they’d get their food). I wonder….

Thanks again, Mith, for replying.

Mith…. you are the person!

thanks.
B

Good point, Canalon, and thanks for responding. Like Mith, you are also The Man. But I’m still wondering about any changes to the 02 over time… does sunlight, for instance, break down oxygen? Would it be absorbed by anything else in the environment – those dead seas, the rocks and earth, etc.?

Right, good point. I also found this from a general article on bacteria, which answers quite a bit of my earlier question:

"Bacteria are solely responsible for the 20% of the atmosphere that is oxygen, which is a highly reactive gas that took millions of years of evolution to harness correctly. If there was a way to kill all bacteria, the amount of oxygen on Earth would drop to zero, as it literally floats right out of the atmosphere and must be created constantly. While plants definitely play a role, they themselves could not exist without bacteria."