Campylodiscus (hibernicus?)

[cuxlander]

Hello forum,

this empty Campylodiscus reluctantly permitted me to turn it into various positions:









Transmitted light, Stacks of average 20 layers. Zeiss Neofluar 40x.
Roughly 100 µm diameter. I'll try to get e cleaner specimen next time , preferably alive.
Cannot beat SEM though.

Cheers, Hans

[Hobbyst46]

Nice views!

[KurtM]

That's one of the nicest presentations I've seen yet for describing the very confounding shape of these things.

Wonder if you might add a comment or two on how you manipulated the specimen to get your various perspectives? Again, nicely done!

[75RR]

Great sequence of images showing its convoluted form!

I second KurtM's inquiry

My efforts to reposition diatoms consist of the very hit and miss methods of adding and removing water, tapping the stage and most drastic of all - moving the cover slip.

[MicroBob]

Hi Hans,
great images! That must have cost a lot of patience to rearrange the diatom frustule several times.
The Campylodiscus is one of my favourite diatoms - where did you find it?

It really would be a nice diatom to put on the tip of a needle and rotate under a SEM to put together a moving GIF from images from different angles.

Bob

[cuxlander]

Hi,
thanks for your comments!

@ KurtM and 75RR: I am using concave slides. Turning specimens is, like 75RR described the method, "hit and miss". I touch the cover glass with a needle and/or slightly move it aside. Not much of a miracle.

@Bob: I found them occasionally in the mud of the Kreidesee Hemmoor (no doubt you have heard of this lake). A flooded former chalk pit. pH ~ 8.5, ~ 585 µS (high amount of dissolved minerals).

The examples from my earlier posting viewtopic.php?f=6&t=5272&p=47564&hilit= ... cus#p47564 are from the same lake.

Regards, Hans

[MicroBob]

No, actually I haven't hear of this moor before...
Do you think the diatom is recent or fossil?
I have found Campylodiscus in a plancton sample from northern Atlantic, 400km south of Greenland so had assumed that it is a marine species.

[cuxlander]

Moin Bob,

the Kreidesee (Chalk-Lake) is a rather deep and very clear lake in the Cuxhaven area. It is a sport-divers hotspot.

Yes it is recent and I also frequently find live specimen. Their contents regularly obscures stacks.



Like with other diatoms empty specimen produce crisper stacks.

Cheers,
Hans