Yellow spots marking the way

[mike barnes]

I've noticed in some distant far off place that I'm digging, ie South Wales, that there is an abundance of yellow patches, possibly algae or some sort of living thing, which coats the rocks. It seems to be only in the sections with a fairly strong draught, and I'm wondering if it really is as the title suggests, follow the yellow spot road, (it's a large boulder choke). Does the continuous draught somehow feed/nurture this apparently living organism. Anybody know what it is and indeed,  is it showing me the way to that monster passage?

 

[whitelackington]

Is it shiney, like gold?
Saw some stuff like that a few years back in Taitham Wife, Yorkshire.
We had a biologist with us and she said it seemed to be alive. :doubt:

 

[Pitlamp]

It'll not be algae - these are mainly unicellular aquatic plants which need light energy to photosynthesise.  They are more likely to be fungi, which feed saprophytically (they secrete enzymes onto dead organic matter and absorb the digested molecules) so they don't need light energy. 

Your suggestion that they might help find the route is quite interesting.  They reproduce from spores, which are easily transported by air currents.  So their existence may well indicate where draughts exist - or sometimes exist.  Hence they may well provide at least one indication of where to dig.

(Anyway, never mind all that - get some logs written up for the CDG Newsletter!)

 

[JB]

A similar thing occurs in Ashford Black Marble Mine in Derbyshire. Bright yellow blobs on the floor in one section of passage. I noticed them a year or so ago but they weren't there before. There's a collapsed entrance at the end of the passage (about 20 metres away) which air blows through and it looks as though someone has spilled some food on the floor and then the fungi has got to it. Since it's a long way to another entrance I expect they got blown through the collapsed entrance. The mine has been worked on and off since the 1700s but is now mainly used by outdoor centres.

If you were near the surface that would be interesting.