Yellow lichen-like stuff on cave walls

[Subpopulus Hibernia]

Does anyone know what this stuff is? I see it all over the place. It also comes in a silvery-white colour but the golden-yellow colour stuff is more common.

And what exactly is it living on? The only observation that I've made is that it usually occurs in moist places, near pitches and the like where there's spray in the air.



Macro close-up from a cave in the north-west of Ireland. Image area is about 4cm across.

 

[Antwan]

You are probably right with Lichen, I believe it doesn't photosynthesize or at least all the many types that are not green 

I stand to be corrected by someone who knows something about this though  :bow:

 

[susie]

http://www.cambriancavingcouncil.org.uk/cavelife/wales/bacteria.html

 

[Rob]

I remember at the opening session to the ICS in Brno someone (i believe it was Annette Summers Engel) presenting some great info about bacteria and other organic things in caves. She mentioned this yellow "stuff", which i believe was indeed a type of lichen.

The only potentially useful piece of information that i did keep is that it is strongly hydrophobic, hence collecting water droplets on the surface making it glisten golden under our headlights. A quick google of "hydrophilic lichen" bring up some interesting things....

 

[Peter Burgess]

I am not sure if this applies to the yellow stuff, but similar white stuff that occurs in places in the Surrey quarries fluoresces in UV.

 

[gus horsley]

If it's not far from the entrance it's probably lichen.  There are also slightly luminous varieties.  If it's deeper underground it could be a secondary mineral deposit.

 

[Peter Burgess]

The stuff found in Surrey only ever sees the light from cavers' lamps. It also seems to be confined to either (a) busy places that see lots of visitors, or (b) places that carry the natural draught through the system, or maybe both.

 

[Rob]

I remember at the opening session to the ICS in Brno someone (i believe it was Annette Summers Engel) presenting some great info about bacteria and other organic things in caves. She mentioned this yellow "stuff", which i believe was indeed a type of lichen.

The only potentially useful piece of information that i did keep is that it is strongly hydrophobic, hence collecting water droplets on the surface making it glisten golden under our headlights. A quick google of "hydrophilic lichen" bring up some interesting things....

Having thought about it a bit more, i'm pretty sure the stuff referred to by Annette was a bacteria.

 

[Ed W]

I seem to recall a presentation by Diana Northup at the Vulcanospeleology conference in 2006.  She stated that the silver/gold stuff with drops of water on it are hydrophobic bacterial mats.  There is a load of interesting stuff on her website at http://www.caveslime.org/

 

[Subpopulus Hibernia]

I seem to recall a presentation by Diana Northup at the Vulcanospeleology conference in 2006.  She stated that the silver/gold stuff with drops of water on it are hydrophobic bacterial mats.  There is a load of interesting stuff on her website at http://www.caveslime.org/

Great website, thanks.

Here's her description of bacterial mats in lava tubes.

These bacterial mats were thought to be made of Actinomycetes, bacteria that break down complex organic matter.

Actinomycetes are known to thrive in environments where food is meager and living conditions extreme; they are commonly found living in caves.

The bacteria gain their energy from organic matter that seeps in the cave in water from the surface. Microbes on the surface break down organic matters, such as leaves. The compounds then mix with water on the surface, which then drips into the cave.

Actinomycetes also come in different colors. They can be pink, silver, white, yellow, or gold.

Different pigments in the bacteria produce the colors. Scientists do not known why or how the bacteria make these pigments. These colors are seen all over the world; caves in the Azores have gorgeous gold-pigmented bacteria on the walls.