Slowdown of Earth's spin caused an oxygen surge

At any given time, half of earth is shined upon and half is in darkness. Those two hemispheres have rotational periods of 24 hrs. The whole planet gets 12 hrs. light and 12 hrs. darkness.....per rotation.

Now double the spin rate. Now we get 2, six hr. periods of light and 2, six hr. periods of dark.....for the same total of 12 hr. light and 12 hr. dark every 24 hrs. Same amount of light per 24 hrs.

Any difference the tilt makes.....is countered by that same tilt....six months later. For a light duty cycle of 50%. Any spin velocity gives 50%. Even very slow ones.

The only way to increase the amount of light is........brighten the sun.....or move closer to it.

Even if one could squash the "elliptic orbit"......to bring us a closer perihelion........it would also move the aphelion further away.
 
At any given time, half of earth is shined upon and half is in darkness. Those two hemispheres have rotational periods of 24 hrs. The whole planet gets 12 hrs. light and 12 hrs. darkness.....per rotation.

Now double the spin rate. Now we get 2, six hr. periods of light and 2, six hr. periods of dark.....for the same total of 12 hr. light and 12 hr. dark every 24 hrs. Same amount of light per 24 hrs.

Any difference the tilt makes.....is countered by that same tilt....six months later. For a light duty cycle of 50%. Any spin velocity gives 50%. Even very slow ones.

The only way to increase the amount of light is........brighten the sun.....or move closer to it.

Even if one could squash the "elliptic orbit"......to bring us a closer perihelion........it would also move the aphelion further away.

For light arriving in a given period you are correct however what you need to factor in to get back to the OP is that plants/ organisms typically are not on/ off in their activity.
In terms of the bacteria you have not considered that processes do not become efficient immediately, so if it takes 2 hours to become fully productive and then shutdown is immediate upon darkness; you will get less output in 4x4hs as opposed to 2x8hrs.

Weirdly my work situation requires me to be at two locations each day... To close my computer and then re-set up takes 30 minutes... That is an hour lost each day, but if I was to remain in one place, I would lose 30 minutes.
 
Microbial mats in the Early Archean were all at the surface, not in "sinkholes". They released oxygen everyday. Why should it be noteworthy that if the Earth took longer to go around once that photosynthesis would add more oxygen? It's not what's added that is important. It's what's removed also. The only way that NET atmospheric oxygen can be increased is to bury photosynthetic carbon...organic matter and biocarbonates. Otherwise the carbon cycle recycles the biomass back to CO2. It's called aerobic respiration. There is no evidence of any massive amounts of buried carbon at that time. But microbial respiration is why the oxygen is so low in that sinkhole. It is not a naturally low oxygen environment.