Edited: Various Desmids from a Sphagnum Fen

WalterD · Post by **WalterD** » Tue Jun 06, 2017 11:31 am

Finally it was time to have another look into one of the local Sphagnum fens. My previous visit was during wintertime, late spring should provide significantly more desmids; both in number and variation. Besides all the other microorganisms populating the samples -that could easily fill another post-, I can confirm the trip was worth the effort.
In this post therefore I'd like to focus on the Xanthidium armatum (images 1&2) and two Micrasterias; the Micrasterias thomasiana (images 3&4) and the Micrasterias truncata(image 5).
The Armatum was abundant and dominating the sample, the first time though I actually saw it through the lens. When going through one of the samples a 2nd time I discovered these desmids also appear in short chain like forms, (photo 2), not previously seen either.

I've been using the opportunity to equip my new Orthoplan with a high NA darkfield condensor I bought earlier on for the Ortholux 2. Previously it did not seem to "talk" with the Ortholux 2, i.m.o. it seems to work out much better in this setup (but feel free to judge for yourself).
So all photographs are made with a 100x Leitz Fluotar (0,6-1,2) iris objective, except picture 4 (63x/1,30 brightfield)

Thanks for looking!

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carlos.uruguay · Post by **carlos.uruguay** » Wed Jun 07, 2017 4:17 am

Very nice photos

Jacek · Post by **Jacek** » Wed Jun 07, 2017 1:42 pm

Very nice

Marek Mis · Post by **Marek Mis** » Wed Jun 07, 2017 11:46 pm

Very nice images !

The chain like form of Xanthidium is not unusual. Many desmids "create" these forms for the short period of time just after cell division.

Marek

Cyclops · Post by **Cyclops** » Thu Jun 08, 2017 12:01 am

Fantastic set!

WalterD · Post by **WalterD** » Sat Jun 10, 2017 2:22 am

Thank you all.

Because the water from the fens remains the same for weeks or even months, it's always possible to go through the samples again.
For me this was handy as it allowed me to find desmids I did not discover previously or make a bit different photographs. Below is my best effort for determination. I added an image of a green alga as well,
not the subject of this post but maybe also nice to see -and coming from the same sphagnum fen.

6 Xanthidium armatum
7 Clorococccum (green alga)
8 Euastrum elegans
9 Micrasterias truncata
10 about 20 mu tall, not identified yet (anybody?)
11 Bambusina (piece of, there were longer strings in the samples)

All with the same Leitz Fluotar 100x iris objective, double oil immersion.
For the ones who don't know this: that's a drop of oil between the lens of the objective and the object, and one between the lower side of the object glass and the condenser lens.

@ Marek: Indeed. They might break due to turbulence when fishing with a plankton net. The sample with the "longer chains" of Xanthidium was taken by filling a bottle with water.

carlos.uruguay · Post by **carlos.uruguay** » Sat Jun 10, 2017 5:13 am

Nice photos.
10 maybe Staurastrum genre without security

WalterD · Post by **WalterD** » Sat Jun 10, 2017 11:26 am

Thanks Carlos,
Indeed it looks like a smaller Staurastrum desmid. This genus appears to be common in the dutch fens. Noted there are many different species, this one actually has multiple "legs".

regards,

Walter

De hecho, parece un desmid menor de Staurastrum. Este género parece ser común en los fens holandeses. Tenga en cuenta que hay muchas especies diferentes, este en realidad tiene múltiples "piernas".

carlos.uruguay · Post by **carlos.uruguay** » Sat Jun 10, 2017 12:17 pm

Jacek · Post by **Jacek** » Sat Jun 10, 2017 2:01 pm

Very nice