Stigonema Mammilosum

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hkv
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Stigonema Mammilosum

#1 Post by hkv » Wed Apr 08, 2020 11:34 am

This photograph shows a beautiful (and relatively large) terrestrial cyanobacteria often found growing on rocks. Stigonema Mammilosum is a short branching species that can be found as blackish crusts and biofilms on inselbergs (isolated rock hill, knob or ridge) in many places on earth. Alexander von Humboldt, a Prussian naturalist and explorer, described but misinterpreted the reason for these black crusts and wrote in 1849 that certain rocks seems to:

“develop a greyish-black cover which does not penetrate more than 0.01 line (0.02mm) into the interior of the rock… the sheath appears to contain manganese oxide and carbon”.

Due to the fact that the species can grow on rocks, they can survice without water for extensive periods of time. Also, they have the ability to adapt to high light intensities, unlike many other species of cyanobacteria. When rain falls, photosynthetic activity is restored within 60 minutes after rewetting following desiccation.

This sample was isolated from fully exposed rocks in Switzerland. Stigonema Mammilosum is a filamentous cyanobacteria with true branching (similar to plants) which gives it its characteristic appearance.

Image
Stigonema_Mammilosum_DIC_2_2048 by Håkan Kvarnström, on Flickr

Image
Stigonema_Mammilosum_DIC_3_2048 by Håkan Kvarnström, on Flickr

Image
Stigonema_Mammilosum_DIC_1_2048 by Håkan Kvarnström, on Flickr

Image
Stigonema_Mammilosum_Fluo_1_2048 by Håkan Kvarnström, on Flickr

viktor j nilsson
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Re: Stigonema Mammilosum

#2 Post by viktor j nilsson » Wed Apr 08, 2020 11:39 am

Truly spectacular photos, Håkan.

Inselberg is such a delightful word, too.
Last edited by viktor j nilsson on Wed Apr 08, 2020 6:07 pm, edited 1 time in total.

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75RR
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Re: Stigonema Mammilosum

#3 Post by 75RR » Wed Apr 08, 2020 12:36 pm

Beautiful images ... you have raised the bar!
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sinabro
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Re: Stigonema Mammilosum

#4 Post by sinabro » Wed Apr 08, 2020 3:06 pm

Wow, very very nice hkv...

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KD Arvidsson
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Re: Stigonema Mammilosum

#5 Post by KD Arvidsson » Wed Apr 08, 2020 7:18 pm

Woow i get jealous, great job hkv :D //KD
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KurtM
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Re: Stigonema Mammilosum

#6 Post by KurtM » Thu Apr 09, 2020 12:46 am

viktor j nilsson wrote:
Wed Apr 08, 2020 11:39 am
Truly spectacular photos, Håkan.

Inselberg is such a delightful word, too.
Indeed!

Wonderful post, thank you Håkan. Please accept this Uber Geek Award all the way from Texas ---> :ugeek:
Cheers,
Kurt Maurer
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hkv
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Re: Stigonema Mammilosum

#7 Post by hkv » Thu Apr 09, 2020 3:46 pm

Thanks all! It is truly an interesting species but difficult to culture. I have them in a petri dish, but they are not growing at the moment. Also have a batch in culture growth media with very limited growth. Trying to make a few more strands to photograph. Will try using an oil objective. These very taken with a water immersion objective so I should be able go get better resolution and detail with the oil NA1.45 (if I can get enough working distance).

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75RR
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Re: Stigonema Mammilosum

#8 Post by 75RR » Sun Apr 12, 2020 11:44 am

These very taken with a water immersion objective so I should be able go get better resolution and detail with the oil NA1.45 (if I can get enough working distance).
Looking forward to that!
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RobBerdan
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Re: Stigonema Mammilosum

#9 Post by RobBerdan » Tue Apr 14, 2020 3:39 am

Beautiful photomicrographs.
RB

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