Does ATP production increase with oxygen availability?

I'm not a biologist so pardon any ignorance on my part. I'm working on a speculative evolution project and I'm looking to understand how the partial pressure of oxygen effects the maximum aerobic performance of muscle. This paper gives the maximum aerobic performance of 100 Watts per KG of muscle. This limit is stated to be observed for both insects and vertebrate fliers and is in turn used to calculate the aerobic flight capacities of various animals. The paper also mentions that squamate muscle tissue can achieve 450 W/kg anaerobically.

I have used the equations listed in the linked paper to calculate the size limits of my speculative world's fauna. The only problem is that this assumes an aerobic power output of 100W/kg of muscle. It is my understanding that aerobic respiration in muscle cells is driven by ATP production and that ATP production is dependant on a constant supply of oxygen. It seems logical that the maximum aerobic power output should be higher if there is more oxygen available.

For context, the atmosphere of this speculative world contains 13.5% O2 at a pressure of 12atm. This equates to a partial pressure of oxygen of 1.62 - approximately ~8x higher than our current atmosphere. In these conditions, there is 8 times the amount of oxygen available for respiration. If oxygen availability is the sole factor in ATP production (thus aerobic muscle power), then this means the aerobic power output would net 800W/kg of muscle (assuming the biology of these creatures are the same as known animals). This is almost double what lizards can produce anaerobically which doesn't seem likely.

My question is how would ATP production scale with available oxygen? I assume there comes a point where mitochondria simply cannot process ATP any faster, which would imply a maximum aerobic power output. I have read that some athletes breathe canned air to reduce fatigue. Does more oxygen equate to more power or does it simply mean that muscle cells would not fatigue as quickly? If I've made any mistakes in my reasoning then please correct them. Thanks.

• Welcome to Biology.SE! Please take the tour and then go through the help pages starting with How to Ask questions effectively on this site and edit your question accordingly. Your "atmospheric composition" isn't for any planet I've ever lived on — please edit your post to use the correct values for Earth or clarify where the values you are using come from and why you are choosing to use them. ——— In addition, each question should be posted separately — this improves the chances that you will get answers for each question and makes the answers more accessible for future users. Thanks! 😊 Oct 20 '20 at 22:06
• Thanks, I thought the description would be sufficient to explain the purpose but I'll restructure it so it's more concise. I don't think the other questions would serve much purpose individually since I don't think you could answer the title question without them. They're more like parameters wthin the overall question. I'll see if I can condense it a bit further though so thanks. Oct 20 '20 at 22:35
• I've reduced the scope of the question. Hope this makes it clearer. Oct 21 '20 at 0:07
• Carbon dioxide removal may be the limiting factor more than oxygen supply, even on Earth. Oct 21 '20 at 8:14