Author Topic: Phytokarst and Photokarren  (Read 1366 times)

Offline JoW

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Phytokarst and Photokarren
« on: February 15, 2021, 02:47:09 pm »
Let's talk about phytokarst (also known as photokarren).
For those that haven't seen these formations, they mostly form in the low-light entrance areas of tropical caves, and have been recorded in Mulu (Borneo) and Vietnam and Venezuela. They take the form of small (up to around 5cm long) spikes, rods or cones that appear to grow towards the light. However, in actual fact they are eroding away from the light. This process is thought to be related to the algae that colonizes them, however only a handful of studies have been conducted and relatively little is known about how they form.
I would be keen to hear from you if you have seen formations like these on your caving travels? Please comment below if you have seen similar formations along with where in the world you spotted them. If you can please also include a photo :)

Offline Pitlamp

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Re: Phytokarst and Photokarren
« Reply #1 on: February 15, 2021, 03:08:00 pm »
See Descent 248 (Feb / Mar 2016) page 15: "More notes on Cave Ha".
Maybe what you're looking for?

Email me off board Jo if you don't have easy access to that edition and / or you want to discuss this further.

Online Speleofish

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Re: Phytokarst and Photokarren
« Reply #2 on: February 15, 2021, 03:54:56 pm »
We also saw them in Papua New Guinea in the partially lit part of the Nare River cave. I don't remember them in any of the other caves we explored. Badlad might have a better memory.

Offline Pitlamp

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Re: Phytokarst and Photokarren
« Reply #3 on: February 15, 2021, 04:28:59 pm »
I've a vague memory that Joyce Lundberg may have done some work on this phenomenon (but could be wrong). If you Google her name - or maybe search on her name in You Tube, you may find something useful.

Offline Pitlamp

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Re: Phytokarst and Photokarren
« Reply #4 on: February 15, 2021, 04:32:16 pm »
Ah - a quick Google of "Joyce Lundberg phytokarst" finds useful stuff, e.g. https://core.ac.uk/download/pdf/70974722.pdf

Offline mikem

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Re: Phytokarst and Photokarren
« Reply #5 on: February 15, 2021, 04:56:41 pm »

Offline JoW

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Re: Phytokarst and Photokarren
« Reply #6 on: February 15, 2021, 05:47:56 pm »
Ah - a quick Google of "Joyce Lundberg phytokarst" finds useful stuff, e.g. https://core.ac.uk/download/pdf/70974722.pdf

Thanks 🙂 yes I've seen that one (the Venezuela example), it's a great paper and fascinating that they can form in sandstone as well as limestone which possibly rules out some processes.

Offline JoW

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Re: Phytokarst and Photokarren
« Reply #7 on: February 15, 2021, 05:48:49 pm »
We also saw them in Papua New Guinea in the partially lit part of the Nare River cave. I don't remember them in any of the other caves we explored. Badlad might have a better memory.

Thanks 🙂 that's interesting, I don't suppose you got any photos?

Offline JoW

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Re: Phytokarst and Photokarren
« Reply #8 on: February 15, 2021, 05:54:43 pm »
Are they that dissimilar to:
https://www.nationalgeographic.com/magazine/2009/11/stone-forest/

The shape is definitely similar, the main differences would be the scale (cm vs metres) and the light orientation in the ones I'm looking for :) I suspect the big ones are mostly formed by rainfall, whereas if water were the only factor in the cave ones it wouldn't explain the need for light and the orientation towards it. Looks like a fascinating place though!

Offline Pitlamp

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Re: Phytokarst and Photokarren
« Reply #9 on: February 15, 2021, 06:21:31 pm »
Jo - you have emails.

Offline mikem

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Re: Phytokarst and Photokarren
« Reply #10 on: February 15, 2021, 06:29:19 pm »
The amount of rain reaching them could explain the difference in scale.

Offline Martin Laverty

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Re: Phytokarst and Photokarren
« Reply #11 on: February 15, 2021, 06:59:28 pm »
This (erosive phytokarst) phenomenon is by no means restricted to the tropics, although first recognised there by Dave Brook and friends on the first Mulu expedition - here in Green Cave [Pic 1]. This is on the small side, some of the Mulu examples photographed by more recent expeditions are metres in length.

On the second Mulu expedition I measured some with Peter Bull [ https://www.academia.edu/1320252/Observations_on_Phytokarst ]. I have since seen good examples of them in limestone in Guizhou, China, and in the Picos de Europa, Spain [Pic 2]; in speleothem in southern Sarawak [Pic 3 (joss sticks for scale)]; and in sandstone at one entrance to the Roraima Sur caves, Venezuela.

Mike Simms reported examples from the west coast of Ireland and the 2019 Greenland expedition found (rather less impressive than Mulu's) examples in the cave entrances there. I have also seen reports from France and Spain...

There is also constructive phytokarst, crayback formations etc...

Offline JoW

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Re: Phytokarst and Photokarren
« Reply #12 on: February 15, 2021, 09:25:32 pm »
This (erosive phytokarst) phenomenon is by no means restricted to the tropics, although first recognised there by Dave Brook and friends on the first Mulu expedition - here in Green Cave [Pic 1]. This is on the small side, some of the Mulu examples photographed by more recent expeditions are metres in length.

On the second Mulu expedition I measured some with Peter Bull [ https://www.academia.edu/1320252/Observations_on_Phytokarst ]. I have since seen good examples of them in limestone in Guizhou, China, and in the Picos de Europa, Spain [Pic 2]; in speleothem in southern Sarawak [Pic 3 (joss sticks for scale)]; and in sandstone at one entrance to the Roraima Sur caves, Venezuela.

Mike Simms reported examples from the west coast of Ireland and the 2019 Greenland expedition found (rather less impressive than Mulu's) examples in the cave entrances there. I have also seen reports from France and Spain...

There is also constructive phytokarst, crayback formations etc...

Hi Martin,

Thank you for your reply :) I have read your Mulu paper, and Mike Simms' Ireland one, but it's great to hear of some other examples, and interesting to hear they can become so big!

I have also read some papers on the constructive kind, the 'crayfish' ones and stromatolitic speleothems, which I'm also interested in. But here I was specifically searching for more examples of the erosional kind (for which I believe photokarren is the more accurate term as it defines both the light orientaion and the erosional nature, but I have only heard cavers refer to them as phytokarst) as the references to them in the literature are so few and far between.

For reference, which I possibly should have included at the beginning, I am currently a PhD student researching cave microbiology. My primary focus is on calcite precipitating bacteria, however I'm keen to know more about all microbially mediated formations in caves, and hopefully I attempt to discover a little more about how some of them form.


Offline Martin Laverty

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Re: Phytokarst and Photokarren
« Reply #13 on: February 16, 2021, 12:02:29 am »
Hi JoW, So both your photos are of light-directed, constructive forms are they?

Perhaps something like photoliths would be a good term as (photo)karren suggests erosion? Phytokarst is just an umbrella name from earlier reports of surface karst from Hell (in Grand Cayman) and from Kashmir.

Have you seen the article "Branched, spelaeothems from Foxhole Cave, Penwyllt, Brecknockshire, Wales: Biologically-induced Cave Stromatolites" by Clark Friend and Graham Christian in SWCC newsletter 137 (June 2020)? These aren't light directed but sound to be right up your street, as does the moonmilk in OFD, and some of the old studies by Ann Mason /Mason Williams/ Edington in Swansea Valley caves.

PS Did you see the recent news of a pot of ancient 'face cream' made of fat and moonmilk from a China? eg https://www.newscientist.com/article/2266855-2700-year-old-face-cream-was-made-from-animal-fat-and-cave-milk/
While moonmilk tends to be associated with the interior of European caves, it is predominant in the entrances to many tropical caves...

Offline Ouan

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Re: Phytokarst and Photokarren
« Reply #14 on: February 16, 2021, 12:54:45 am »
Phytokarst has been reported from a few caves in Thailand, scattered throughout the country.
The term is sometimes used, wrongly, for the stalactites that grow towards the light (eucladioliths).

Offline JoW

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Re: Phytokarst and Photokarren
« Reply #15 on: February 16, 2021, 10:37:24 am »
Hi Martin,

Apologies, perhaps I caused some confusion- both of the photos are of the erosional kind (photokarren).

I haven't seen the article about branched speleothem, I'll look that one up, thanks 🙂

I've read quite a few papers about moonmilk as it's one of the better studied microbially influenced speleothems. Here's a culture from one of my moonmilk samples, which I hope to get back to soon when I get get out sampling and into the lab again.

Offline JoW

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Re: Phytokarst and Photokarren
« Reply #16 on: February 16, 2021, 10:39:18 am »
Phytokarst has been reported from a few caves in Thailand, scattered throughout the country.
The term is sometimes used, wrongly, for the stalactites that grow towards the light (eucladioliths).

Thanks 🙂 that's interesting to know. I don't suppose you have any photos for comparison?

Offline Ouan

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Re: Phytokarst and Photokarren
« Reply #17 on: February 16, 2021, 11:07:47 am »
Thanks 🙂 that's interesting to know. I don't suppose you have any photos for comparison?

I some photos of eucladioliths, which are common.
These are from Chumphon Provice (photo by Kevin Gammon) and Mae Hong Son Province (photo by John Spies)

I don't have any photos of phytokarst.

Offline mikem

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Re: Phytokarst and Photokarren
« Reply #18 on: February 16, 2021, 11:24:19 am »
Eucladioliths could be as simple as the water on sunny / warmer side of formation evaporates faster than the shady / cave-cooled side, depositing more calcite, so the drip then runs down that edge, bringing it out further.

This book does link the Madagascar pinnacles through also being biokarst: https://books.google.co.uk/books?id=9dlAixcXztYC&pg=PA45&lpg=PA45&dq=photokarren&source=bl&ots=dtciie7gDG&sig=ACfU3U05XZNgPj0owJno5n7tRYXIhauRXA&hl=en&sa=X&ved=2ahUKEwjMsvLcpu7uAhViQkEAHWiXCgk4HhDoATAFegQICBAB#v=onepage&q=photokarren&f=false

Is the photokarren so close to the entrance that it is occasionally hit by slanting rain? (& maybe was more regularly in the past)
« Last Edit: February 16, 2021, 11:40:39 am by mikem »

Offline mikem

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Re: Phytokarst and Photokarren
« Reply #19 on: February 16, 2021, 12:02:14 pm »
Alternatively the shaded side of photokarren stay damp for longer, so more dissolution occurs / algae or microbes can survive better there.

Online Speleofish

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Re: Phytokarst and Photokarren
« Reply #20 on: February 16, 2021, 12:10:15 pm »
JoW, I've probably got an old slide somewhere. I'll try to dig it out.


Offline Martin Laverty

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Re: Phytokarst and Photokarren
« Reply #21 on: February 16, 2021, 02:34:42 pm »
Where are your photos from Jo?

Off topic, but the "Karst Rock Features. Karren sculpturing" book mikem referenced includes a picture from Blah, Derbyshire: Wezzit?

Offline JoshW

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Re: Phytokarst and Photokarren
« Reply #22 on: February 16, 2021, 02:50:09 pm »
Where are your photos from Jo?

Looks like Hang Son Doong to me, both the north side of the second doline?
All views are my own and not that of the BCA or any clubs for which I'm a member of.

Offline mikem

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Re: Phytokarst and Photokarren
« Reply #23 on: February 16, 2021, 03:12:16 pm »
Off topic, but the "Karst Rock Features. Karren sculpturing" book mikem referenced includes a picture from Blah, Derbyshire: Wezzit?
The text doesn't help by describing it as NW England...

Offline Fishes

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Re: Phytokarst and Photokarren
« Reply #24 on: February 16, 2021, 03:30:49 pm »
Where are your photos from Jo?

Off topic, but the "Karst Rock Features. Karren sculpturing" book mikem referenced includes a picture from Blah, Derbyshire: Wezzit?

Looks very similar to the view from my back window. Lots of similar features in the White Peak


 

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