Quite The Unusual Diatom

[KurtM]

Cylindrotheca has two very unusual attributes going for it: first, and most obviously, the spirally arranged raphe and girdle bands. This is especially startling when observing them as living things since they very much tend to gracefully roll as they scoot. The second thing is that their frustules are very lightly silicified; so much so that the exceedingly delicate frustules are usually destroyed by acid cleaning. I can personally attest to it too, as they completely disappear from my own sample material after oxidation (it's like where'd they go??). Took me a while to figure this one out.

The last picture is Pleurosigma fasciola, because it came from the same sample, is really cool looking, and I just like the image.

Since these are such super fragile frustules, the brackish-water sample material was very simply cleaned with rinses of DIW and IPA before mounting in Pleurax.

All are single-frames through the Planapo 63/1.40 Oel 160/- lens, DIC, Zeiss WL stand with achr. apl. 1.4 condenser and 12V 100W lamp. Third image has colors inverted and converted to gray scale, all others have suffered minimal post processing.

[Crater Eddie]

Wow! Beautiful images.
CE

[Hobbyst46]

Interesting and enjoyable !

Questions:
1. Third photo - the enhanced contrast is only due to othe color manipulations?
2. Fourth photo - brightfield?
3. Can rinsing with water and organic solvent alone remove organic matter from the diatom ?

[mrsonchus]

Superb images Kurt! Quite stunning structure and form - beautiful indeed.

[MicroBob]

Thank you for posting these two special diatoms, Kurt! They are real beauties!

Did you know that you could expect this fragile species at this spot of collection?

Bob

[vasselle]

Bonjour
Superbes images avec une très belles clarté.
Merci pour le partage
Cordialement seb

[KurtM]

Interesting and enjoyable !

Questions:
1. Third photo - the enhanced contrast is only due to othe color manipulations?
2. Fourth photo - brightfield?
3. Can rinsing with water and organic solvent alone remove organic matter from the diatom ?

Answers:
1. Not entirely. The colors were inverted, then levels adjusted, in this case using the auto function in the Levels tool in Paint.Net. The image was then converted to gray scale.
2. No, still DIC, but with the prism dialed way out. It is my habit to rotate the stage (which rotates the specimen relative to the DIC shear plane), adjust the objective prism, adjust the condenser iris, and introduce the 1st order red compensator in a hunt for max contrast on the sensor (in this case my brand new Canon T7i/800D DSLR camera). I have been having a devil of a time getting reasonable contrast in Cylindrotheca; it's often nearly invisible even under DIC, probably another reason it's seldom reported. Great subject for phase contrast, see below.
3. No, and in fact if you look closely you can see the chloroplasts still in P. fasciloa, although they're now colorless due to Pleurax saturation. Chloroplasts are also present in Cylindrotheca but disappear more fully when mounted for some unknown reason.

So here are a couple more images, this time in phase contrast. First one through the Ph3 Neofluar 63/1.25 Oel 160/- on the Zeiss WL. This one certainly won't win any contests, but it shows the ultra delicate nature of these frustules pretty well.

Second image through the 100x/1.25 Bright Phase cat. no. 1237 on the AO 120, which I recently converted back to its originally intended 12V 100W halogen lamp. (I originally purchased this stand sans lamp holder and power supply and installed LED lighting.)

[zzffnn]

Beautiful work, Kurt.

What is the difference between:

0201 LZN Pn1(3rd image of OP)

and

0201 LZN (2nd image of OP)

I am guessing same frame/source file, but #3 has color inversion and grey scale?

Thank you for sharing.

[JimT]

Kurt, i can only echo all the prior comments. Great!

[hkv]

WOW! Never seen one of these before. Not even on prepared slides. Great find!

[KurtM]

Fan, the colors were inverted, then levels adjusted, in this case using the auto function in the Levels tool in Paint.Net. The image was then converted to gray scale.

hkv, Cylindrotheca does seem to be rare according to what I've turned up in the literature, but I believe rarely seen/noticed is probably more the case. You really gotta be on your toes to pick it up visually, even under DIC, and only in live/raw sample. As I mention above, it disappears in processing (and the literature mentions this fact, which was a major clue to help me nail it down).