Cuckoo Cleeves Closed

[Hughie]

Yawn. If you bothered finding out, for example, the cost of agchems, fertliser etc, and the regulations controlling them, then you may just, eventually, realise that applying them at a level that either causes run-off, or even applying off the target is both an expensive and futile gesture. 

 

[whitelackington]

We know which caves (on Mendip) routinely suffer poor air - the main ones are, in no particular order: White Pit, Maesbury Swallet, Little Crapnell Swallet, Cuckoo Cleeves, Tynings Barrows Swallet and GB Cavern. What we do not know are the reason(s) causing this; however, for the first time we have access to accurate (!) testing devices and may be in a better position to begin pinpointing the cause(s) of poor air. The present debate, however, seems to focus on what to do once it is known that a site has poor air - should a sign simply inform people who then make up their own mind or should access control bodies/landowners be more proscriptive in their actions? - assuming the latter, how often do you test and what is the cut off line/time for reappraising any control(s) placed on the site.

Why limit yourself to a 100 year time frame, though? - surely it's just as easy to say that over the last couple of million years since people have been using caves we haven't figured out the definitive cause of poor air in any individual site and, presumably by extending the line, we therefore won't be able to do so for another x years?

Going off on a fantasy tangent might include high fencing, guard dogs, CCTV cameras, filling sites in with concrete, setting up machine gun nests etc..

Take G.B.Cavern off your list but add Manor Farm Swallet

 

[Les W]

It is my belief (unproven as yet) that ALL caves suffer from elevared CO2 in the summer. It is certain that Swildond does, as a visit to the fossil series of the short round trip will attest. I think the problem is worse in some caves and we need to understand the reasons for this. Hopefully the studies at Cuckoo will shed some light on this.

 

[Clive G]

It is my belief (unproven as yet) that ALL caves suffer from elevared CO2 in the summer.
. . .

The reason why cavers traditionally go on summer expeditions overseas to areas where the caves are generally bigger and/or have a greater throughput of water?

 

[graham]

It is my belief (unproven as yet) that ALL caves suffer from elevared CO2 in the summer.
. . .

The reason why cavers traditionally go on summer expeditions overseas to areas where the caves are generally bigger and/or have a greater throughput of water?

Well, from what I hear a lot of cavers on expeditions this summer have indeed encountered a greater than usual throughput of water.

 

[Slug]

It is my belief (unproven as yet) that ALL caves suffer from elevated CO2 in the summer. It is certain that Swildond does, as a visit to the fossil series of the short round trip will attest. I think the problem is worse in some caves and we need to understand the reasons for this. Hopefully the studies at Cuckoo will shed some light on this.

It's not just Summer time Les, try going into a popular 1st timers/novice cave during the University "Freshers" first trip weekend (usually mid October time), the amount of traffic, most of them puffing and panting, through a combination of exertion and fear, will suck the oxygen out of the air quite well. Below the 20 in Swildons can be quite unpleasant.

Is it also possable that in summer different weather/temperature patterns may account for the (perceived ?) higher C.O.2  levels ?

 

[Clive G]

Clive wrote:
"What you need to be very careful about is whether explosives have been used in this particular cave by persons known or unknown"

From the vegetation in the depression it was obvious that no one had visited the cave for some time. Also, I am fairly sure I would have heard through the grapevine is someone was banging in Cuckoo.

Cuckoo is generally considered to be a suitable trip for beginners and our main concern is for parties who may not be very experienced and also are not aware of any potential bad air problem in the cave.

This bad air experience, and the other threads on this forum about draughts in caves highlights our lack of knowledge about air movements underground. To study these we need some way of detecting and monitoring very slow air movements. There are theories about how the CO2 will sink downwards in a cave, but these would suggest that the air would not be as bad at higher levels and that the further down you go the higher the concentration of the gas. We know this is not always the case.

In the late 1960's and 1970 we were digging and banging at the bottom of Cuckoo and did not experience any problems with the air. The bang fumes always cleared between trips which were frequently both mid week and at weekends. There were later reports that the Radon testers found high levels of that gas in some parts of the cave, which does suggest that there was limited air movement where they found the Radon. The only possible explanation I can suggest for these facts is that there is a localised air circulation at the bottom of the cave which is separate from the main passage.

We suspect that the lid on the cave entrance is restricting the airflow in the upper parts of the cave and contributing to the bad air problem. There is no obvious rotting vegetation in the cave to be generating the CO2.

So, if cavers are not visiting the cave or carrying out digging work inside, then the build-up of CO2 must be connected with additives to the water - other than the normal chemistry of H2O.

If CO2 were to be 'sinking' from the surface then you'd expect there to be a deficiency of oxygen in the general atmosphere - which has not yet been suggested to be the case by climate-change scientists.

From the above, the draught in the cave is normally quite sufficient to clear the air. However, there are certain conditions of temperature and air pressure where draughts neither blow into a cave nor out. At such a 'stand' any excess of CO2 building up inside or being taken into the cave will not be dispersed in the usual manner.

I suspect that the measurement of high levels of radon underground is equally as much connected with particles brought down by rainfall within the catchment of the area for the caves concerned, rather than purely being an effect caused by the proximity of adjacent 'radioactive' strata or mineralisation.

A premise used in Stanley Kubrick's film 'Dr Strangelove' is that fluoridation of the water supply was a conspiracy to pollute the precious bodily fluids of the American people! But perhaps it is some other contaminant or chemical reaction that we need to be more concerned about?

 

[Duncan Price]

If CO2 were to be 'sinking' from the surface then you'd expect there to be a deficiency of oxygen in the general atmosphere - which has not yet been suggested to be the case by climate-change scientists.

There is a reduction in oxygen in the atmosphere correlating with the increase in CO2 see: http://blogcritics.org/scitech/article/atmospheric-oxygen-levels-fall-as-carbon/ . Over the past 550 million years the atmospheric concentration of O2 has varied naturally between 15 and 30%..

I think that it is not credible to blame high CO2 in caves to global warming (even if you believe in global warming).

I suspect that the measurement of high levels of radon underground is equally as much connected with particles brought down by rainfall within the catchment of the area for the caves concerned, rather than purely being an effect caused by the proximity of adjacent 'radioactive' strata or mineralisation.

In which case can you explain the regional differences in Rn?  If it came from the atmosphere then it would be fairly uniform across the country.

Duncan

 

[dpegg]

any news of the state of cuckoo?

 

[Peter Burgess]

Aubrey will know, but in anticipation of a better update, he reported a slight reduction in carbon dioxide levels (due to the solid gate being replaced by a grill) at Hidden Earth, but the level was still high in the entrance area.

As to where the gas comes from, the presentation at Hidden Earth was very interesting, and as I recall, farming practices are more or less ruled out, at least as far as CC is concerned.

 

[exsumper]

In simple terms:- The source of the sinking CO2 is well established and is a combination of rotting vegitation and residual soil CO2. It is also associated with the growing season, July -September,  green plants respire 40% of the CO2 they aquire from the atmosphere into the soil via their roots, this production also increases with temperature.  The CO2 then sinks into the Ground and then into caves as it is heavier than air. It is also carried into caves dissolved in groundwater through fissures, It then degasses from solution upon reaching air/cave passage. If there is a stream in the cave much of it will be carried away by resolution into the stream water.  It seems fairly obvious that this is the reason for higher levels in the summer, a combination of the growing season and plants producing more CO2 due to higher temperatures and lower stream levels, dissolving less CO2 from the cave atmosphere than in the winter.

 

[whitelackington]

Where do you get that knowledge from?

 

[exsumper]

Most Karst Science Textbooks.
Such as

"Karst Hydrogeology and Geomorphology" Ford,D.C. & Williams 2007
"Cave Geology" Palmer,A.N. 2007.
"Speleogenesis" Klimchouk,A.B. 2000 & 2008.

I missed out the fact that microbial activity is probably the main contributor .

 

[Peter Burgess]

Yes, that's just what Aubrey said - simple! He also said that the process accelerates markedly above 20 deg.C, which means that with higher mean summer temps this problem is not going to disappear, unless we reach temperatures of 40 deg.C, when it is too hot for the process to occur.

 

[Aubrey]

Yes, that's just what Aubrey said - simple! He also said that the process accelerates markedly above 20 deg.C, which means that with higher mean summer temps this problem is not going to disappear, unless we reach temperatures of 40 deg.C, when it is too hot for the process to occur.

Small correction - the generation of CO2 increases exponentially between 20 deg C and 40 deg C and almost stops at 50 deg C. according to the following article:

http://www.ias.ac.in/currsci/mar102002/510.pdf

another interesting link:

http://books.google.co.uk/books?id=BILt0bdU6AsC&pg=PA35&lpg=PA35&dq=co2+production+roots&source=bl&ots=r1zyUml-j8&sig=QHlHhP6qamI3zSUr0zmAELqK8lY&hl=en&ei=y6-zSoOLJqOK4ga-m4R9&sa=X&oi=book_result&ct=result&resnum=1#v=onepage&q=co2%20production%20roots&f=false

either way "I fink the answer lise in the soil" 

 

[Peter Burgess]

Excellent. So we will all be toast by the time the problem solves itself. I should have taken notes at Churchill!

 

[ttolyaj]

A simple question if more CO2 is going into a cave does that mean higher limestone solution is likely to occur, or formation deposition?

 

[whitelackington]

Why is it worse at Cuckoo Cleaves (than other caves)

That is the real question
Grass isn't more prolificate there is it?

 

[tony from suffolk]

Further to your question Mr Whitelackington; why is the problem so much worse in Cuckoo Cleeves than it used to be?

 

[whitelackington]

Is it re-opened yet?
With all this wind and rain the CO2 might have somewhat dissipated.
Excellant programme last night on the box about lakes in Africa giving off tidal waves of freezing cold CO2
and wiping everybody out, virtually instantly.