Extremely high oxygen worlds

[Moontanman]

Could land based life exist on a world with high levels of oxygen? At what point would organic matter burst into flames if exposed to air? Would pressure be a factor?

 

My speculation is that water worlds, global oceans no land, would or at least could support very high oxygen levels and or pressures while worlds with a significant land area would not due to oxidation of exposed surfaces.

 

Thoughts?

[John Cuthber]

"Could land based life exist on a world with high levels of oxygen? "

We do.

"At what point would organic matter burst into flames if exposed to air? "

Did it occur to you that you do not observe this and that oxygen is noted for the ability to relight a Glowing splint?

"My speculation is ..."

It's a good idea to know what you are on about before you speculate

[Moontanman]

"Could land based life exist on a world with high levels of oxygen? "

We do.

"At what point would organic matter burst into flames if exposed to air? "

Did it occur to you that you do not observe this and that oxygen is noted for the ability to relight a Glowing splint?

"My speculation is ..."

It's a good idea to know what you are on about before you speculate

 

 

Actually I've given a bit more thought to this that you might think, in fact at one bar pressure earth life would be difficult at more 30% O2 or so, the higher you go up the more likely a lightning stroke is to ignite the entirety of surface life. In fact there is some evidence that when the earth did have an oxygen content of above 30% wide spread wide fires were quite common. I'm not if anyone has taken this speculation to it's at least semi obvious conclusion but land based life would be more difficult as the oxygen content went higher.

 

Then again fire resistance could also evolve but on Earth it seems that fire resistance has evolved but is limited. At some point any fire would be an explosion instead of a roaring fire..

[rangerx]

Oxygen at a partial pressure of greater than 2.0 is toxic to humans.

 

Would pressure be a factor?

[John Cuthber]

 

 

Actually I've given a bit more thought to this that you might think, in fact at one bar pressure earth life would be difficult at more 30% O2 or so, the higher you go up the more likely a lightning stroke is to ignite the entirety of surface life. In fact there is some evidence that when the earth did have an oxygen content of above 30% wide spread wide fires were quite common. I'm not if anyone has taken this speculation to it's at least semi obvious conclusion but land based life would be more difficult as the oxygen content went higher.

 

Then again fire resistance could also evolve but on Earth it seems that fire resistance has evolved but is limited. At some point any fire would be an explosion instead of a roaring fire..

Roughly two thirds of the Earth's surface is pretty much immune to fires.

Plenty of things live there.

[Moontanman]

Roughly two thirds of the Earth's surface is pretty much immune to fires.

Plenty of things live there.

 

 

This is true but oxygen levels on the Earth are not high enough to make any fire turn into an explosion, 20% is not high... 20% is normal for us, if oxygen was twice as high even wet things could burn fiercely.

 

One of the points I made was that high oxygen levels could be expected on worlds with no land area but I am asking if land surface areas cause oxygen levels to be more moderate. Oxygen was around 30% + in the carboniferous and giant insects were able to live due to this fact. But oxygen has never risen that high again.

 

Is there a mechanism that would cause oxygen levels to decline or is it simply random?

Oxygen at a partial pressure of greater than 2.0 is toxic to humans.

 

 

 

Yea, I learned this in scuba classes, one of the first things you learn is that you can't breath pure oxygen under pressure...