Hypoxia at 15,500'?

[kelpdiver 2]

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750x.21 = 157.5 atms PPO2. (Rounding to 3 atms/100ft)

We'd certainly need an adaptation with the exposure table for 1.6atm at only 45 minutes.

Are you suggesting that the actual oxygen content of the ocean depends on depth? (as opposed to the theoretical solubility at that depth)

Unless you're in a pressurized vessel or using some sort of scifi liquid breathing system from the Abyss, you're breathing gas at ambient pressure. So you take the percentage of the gas that is oxygen and multiply by 750.

There is of course no practical solution for current human physiology. Record for open circuit is just over 1000ft, and only one of the two people returned alive.

The oxygen content of the water is driven mostly by temperature. The central coast of California supports a lot of life because of frequent upwellings of deep water, though deep here is only 10k ft. Since water doesn't compress to a significant degree, I don't think gas solubility changes, but feel free to correct me on that.

[Reginald 0]

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When he got to me he asked how I was feeling, and my answer was “…well, you know what you feel like when you have been doing coke all day and smoke a little hit of grass to take the edge off…” The captain said “Sir, I wouldn’t know, are you alright?”

LOL.

"We've been looking for the enemy for some time now. We've finally found him. We're surrounded. That simplifies things." CP

[Beerlight 0]

Cool beans..!! I knew most of the crew at the Edwards unit, (and I'm curious to who that was!) and it's a shame they closed it.

Oh, and I forgot, it's currently $50 (non-refundable), if anyone wants to go through a military altitude chamber (which I highly recommend)..

Here in Houston, we give the training for free, although we have stopped civilian training temporarily until we work out some "new" red tape with the FAA...

cheers everyone,

Buck

[justaflygirl 0]

My highest jump was at 16,000...I didnt have have "hypoxia" type symptoms, I was just so stoked that we got so high. I do know that different people suffer from symptoms of hypoxia at different altitudes.

[mjosparky 4]

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Cool beans..!! I knew most of the crew at the Edwards unit, (and I'm curious to who that was!) and it's a shame they closed it.

PM sent.

My idea of a fair fight is clubbing baby seals

[kallend 2,027]

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750x.21 = 157.5 atms PPO2. (Rounding to 3 atms/100ft)

We'd certainly need an adaptation with the exposure table for 1.6atm at only 45 minutes.

Are you suggesting that the actual oxygen content of the ocean depends on depth? (as opposed to the theoretical solubility at that depth)

Unless you're in a pressurized vessel or using some sort of scifi liquid breathing system from the Abyss, you're breathing gas at ambient pressure. So you take the percentage of the gas that is oxygen and multiply by 750.

There is of course no practical solution for current human physiology. Record for open circuit is just over 1000ft, and only one of the two people returned alive.

The oxygen content of the water is driven mostly by temperature. The central coast of California supports a lot of life because of frequent upwellings of deep water, though deep here is only 10k ft. Since water doesn't compress to a significant degree, I don't think gas solubility changes, but feel free to correct me on that.

The question related to creatures of the deep ocean. I assumed that did not mean gas breathing humans.

I interpreted the question to mean what is the O2 partial pressure in equilibrium with the ocean water at 25,000ft depth. I don't believe it is significantly different than at the surface, and it may even be less because that's an awful long way down for dissolved oxygen to diffuse.

...

The only sure way to survive a canopy collision is not to have one.

[kelpdiver 2]

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I interpreted the question to mean what is the O2 partial pressure in equilibrium with the ocean water at 25,000ft depth. I don't believe it is significantly different than at the surface, and it may even be less because that's an awful long way down for dissolved oxygen to diffuse.

But given sufficient time, like the history of the world, shouldn't it happen? Unless the denizens of the deep consume it as quickly as it comes.

Ah, looking further, lowest point is 500-1000m due to decomposition. See bottom of: http://www.ocean.uni-bremen.de/EInfo/materialien/elemOc/top12-17/topic15.html

Not sure why the curve comes back at the bottom edge, though.

[obelixtim 150]

This conversation is getting a bit deep....... I'm a little bit out of my depth here......in over my head so to speak..........

Can a chocolate fish swim????.....

My computer beat me at chess, It was no match for me at kickboxing....

[dnewcomer 0]

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I don't believe it is significantly different than at the surface, and it may even be less because that's an awful long way down for dissolved oxygen to diffuse.

It is significantly different. The oxygen level at great depths (eg. 25,000+ feet) is very low.....far lower than near surface or in atmospheric air. The ocean currents do not exchange sea water that much between the surface and great depths. The reason for this is two fold: (1) colder water sinks and warmer water rises, tending to keep a column of ocean water in place with little top to bottom circulation; (2) water with higher salinity is denser and also sinks.....water near the surface has less saline, therefore tends to remain there. This also limits sea water movement.

The two things that add dissolved O2 to sea water are (1) diffusion from surface (interface with air); and (2) photosynthetic organisms. There is virtually no light at great depths, therefore phytoplankton and photosynthetic bacteria cannot produce O2 as they do within 100 - 200 meters of the surface.

Also sea water at 25,000' is very cold and exerts a crushing ~500 atmospheres of pressure (OK....in limited areas near the oceanic trenches where hot magma is upwelling there are some warm spots). Very little dissolved gas of any kind is present at such depths.

Dave
WEB SITE: www.newconthenet.com

[kelpdiver 2]

Dave, the citation I listed indicated that at 10,000ft, the O2 level was more than half the max at any depth. It was a bit contradictory as to what happens beyond the 4000m mark on the graph.

[dnewcomer 0]

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Dave, the citation I listed indicated that at 10,000ft, the O2 level was more than half the max at any depth. It was a bit contradictory as to what happens beyond the 4000m mark on the graph.

That sounds about right. I believe you mean 4,000 feet, not meters. Below ~4,000 feet, levels of dissolved O2 in seawater actually increase slightly. This is thought to be due to the fact that there are few organisms there to extract O2 from the water and cold water can hold more dissolved gas than warm. Therefore any gas that gets below 4,000' will stay there a very long time......millenia actually. Not much can happen to it.

Water at great ocean depths is thought to remain stable for millions of years. I'm not sure there is enough data on the content of dissolved gases in sea water at extreme depths (25,000' - 35,000') to generalize for all locations in all the oceans at all times.

I lied. Pressure at a depth of 25,000' is nearer to 850 atmospheres, not 500 atmospheres. (In any case, I'm not going there soon.)

To recapitulate the point of this S&T thread: from a physician's point of view, skydivers who are smokers or those with chronic lung disease should be extremely careful when jumping from altitudes above 14,000'. Healthy individuals are not at as great a risk for occurrence of an adverse event if they follow recommended precautions. Also avoid smoking within several hours of making a high altitude skydive to purge your lungs of carbon monoxide. (However a few beers the night before should be OK.)

Dave
WEB SITE: www.newconthenet.com