As soon as you add dry caves in the mix it changes the game completely, it goes from easy cave diving to a much more complicated situation, turning a leasurly cave diving exploration into a richer underground experience.
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As soon as you add dry caves in the mix it changes the game completely, it goes from easy cave diving to a much more complicated situation, turning a leasurly cave diving exploration into a richer underground experience.
Couple of random thoughts...
I got to 8% CO2 once during a medical experiment without changing my breathing frequency or depth, so not everyone feels anxiety with higher than normal CO2, (I was labelled a "non-responder"). For those interested in the details I started with 95% O2 and 5% CO2 and breathed a closed loop till we hit 8% CO2. I was quite relaxed throughout, although this was in a lab and I wasn't exerting.
Anyway, my second gem is that Tommy Graham's cave in the Nullarbor has a high CO2 level. It is also not that easy to get to. On my first and second visits, (each one 600+ miles drive), I looked around. On my third visit I tried walking around but tired soon, on my fourth trip I filled a couple of empty and washed Pepsi-bottles with water at the entry lake. When we surfaced in the chamber I unscrewed a cap, emptied the water and collected a sample of chamber gas. I did this again at the top of the rockpile you need to climb over to reach the second sump. My question was "If we need to leave someone here after diving the second sump and go for more gas, is it worth staying up the top or doesn't it make any difference?"
Then I asked for help on the CDAA forum and someone was kind enough to offer to analyse those samples at work. Turned out it was 1.9% CO2 at the surface, and 19.5% O2. At the top of the rockpile it was 1.2% CO2 and 19.9% O2.
So, if you have the option of returning later, I recommend collecting some gas with a plastic Pepsi bottle, for later testing. They are, afterall, designed to hold CO2-soaked liquid.
Cheers
Peter
Lower CO2 in the air chamber?Quote:
Originally Posted by PeterBuzzacott
Hi Forrest
Both samples were collected in the chamber between sumps 1 and 2. As we approached the lake at the end of sump 1 I unscrewed the cap off the bottle, lifted it up through the surface upside-down so the water would pour out and collected a gas sample from an inch above the surface of the lake in the chamber. Then, I emptied the second bottle of water (and collected gas) at the top of the rockpile. CO2 being denser than oxygen, there was higher CO2 and lower oxygen by the lake, compared with at the top of the rockpile.
Ah, you meant the surface in the air chamber! I thought you meant outside the cave.Quote:
Originally Posted by PeterBuzzacott
BTW Dave were is my lighter ;))...Quote:
Originally Posted by DaveP
On symptoms, we have seen smokers can sometimes fail to notice the effects of elevated CO2 for longer than non-smokers.
I suppose they're already accustomed to higher levels of CO2, so it doesn't really feel out of place for them. Or their respiratory drive is already impaired in that respect so it takes more exposure to get a reaction. Hardly clinical, but we've observed it on more than one occasion.
your lighter died eric, the air was safe since we breathed it for 40 mins, but water is acid :)
I only had the balls to breathe that air for 5 minutes... and out of there ;)Quote:
Originally Posted by Neptuno