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Partial pressure of O2, CO2, etc., in Thailand cave

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Regarding flooded caves and partial pressures of key gases.

Lots of people want to talk about the current situation at
Doi Nang Non mountain but some have special knowledge that
might be tapped.

Currently there are dicussions about the low oxygen partial
pressure (percentage, presumably by volume) of 15% at the
team's location compared to a normal value of 21%, this new
level already at the point where it can be causing some
impairment.

Sites like this one have graphic froms which one might hope
to inferred at least some sort of scale information (beware
possible wrap of URL):

 www.cbsnews.com/news/thailand-cave-rescue-latest-updates-today-officials-appear-close-to-launching-rescue-mission-2018-07-07/

Now if water volume is lowered and air volume is increased by
the same amount, something must occur to make up the difference.
According to South Dakota School of Mines these are limestone
formations and therefore quite porous, and, in fact, diffusion
through the limestone may be a major source of replenishment
of the removed water during the monsoon season.

So what is happening in the air spaces to deal with the
increased air volume?

Possibilities:

 o Concomitant lowering of pressure while relative pressures
   remain the same?

 o Ditto, except P_H20 remains constant (partial pressure
   H2O at maximum value for given temperature).

 o Combination effects, with, say chemical reactions or outgassing,
   changing the contributions of other gasses as well.

I am here ignoring the partial pressure of CO2. Of course it
will  be going up as O2 is consumed by the humans in the cavity,
but since some of the waste product of energy production in the
body is H2O, there should be a smaller volume of CO2 produced
than O2 consumed, say, roughly, 2:1.

Finally, between two sealed cavities, does not a water-filled
connecting tunnel act like a manometer so that water level will
rise in the lower pressure chamber relative to the higher
pressure chamber?  Does that mean that if the chamber containing
the team is smaller its water level may remain higher and air
volume lower as the water in the other chambers is drained?
Maybe this is moot because of the permeability of the
limestone in which they are presumably embedded.

George

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Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-07 20:55 -0400
  Re: Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-07 21:30 -0400
  Re: Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-07 22:19 -0400
  Re:Partial pressure of O2, CO2, etc., in Thailand cave Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-07-08 06:11 +0200
    Re: Re:Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-08 01:14 -0400
      Re: Re:Partial pressure of O2, CO2, etc., in Thailand cave Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-07-08 07:30 +0200
        Re: Re:Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-09 02:40 -0400

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