MicrobeHunter.com Microscopy Forum

I recently came across this very pretty bit of greenery while perusing water from a local pond sample, and thought for sure it must be some Desmid I haven't seen before. But a more experienced friend suggests it's the alga Coelastrum. I can see where he gets his ID, but it still strikes me as a Desmid. I say so not only because of its obvious hardened cell wall structures, but also because the golden granules in each cell were really sparkling, twinkling, and jittering with what looked like Brownian Motion after a very Desmid-like fashion. Overall diameter is roughly 0.3 mm.

Of course, Desmids are fairly among the algae, so at least it's gonna be tough for anyone to go too wrong here. Still, where's an expert when you want one?

Great catch and image, although photoshop tells me that your levels are a bit off.

Not seen anything quite like it so can't help with the ID as yet. Will have a look.

Ok Coelastrum sp. looks to be correct. So not a desmid.

Hope you don't mind me fiddling with your image. Will remove if you wish.

Hi Kurt,

a really striking image - very interesting indeed. Have you mounted it in water under coverslip?
It really does match 75's ID suggestion well I think.

First: no, I don't mind you or anyone else tweaking my images ('specially you, Glen), I'm here to learn! And you're right, of course, it does look nicer. I never even thought about adjusting the levels so let that be a lesson to me.

Funny, I have the same book and saw the same illustration. But I'm still not 100% satisfied. I haven't seen any good Coelastrum-corroborating images on the www either, for instance.

John, it was in a glass bottom petri dish on my Nikon Diaphot TMD inverted scope (Rod used to call it the Australian scope).

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Perfect matches are difficult with photos - that's why drawings are still so useful

Wiki has quite a list, so there is a lot of variation and most probably several which have not been described properly.

I am going to go with Coelastrum reticulatum:

http://protist.i.hosei.ac.jp/PDB/Images ... atum1.html

Either way, don't think one can be far wrong with Coelastrum sp.

Species list (Wiki)

Coelastrum astroideum
Coelastrum cambricum
Coelastrum chodatii
Coelastrum crenatum
Coelastrum giganteum
Coelastrum indicum
Coelastrum irregulare
Coelastrum microporum
Coelastrum morus
Coelastrum naegelii
Coelastrum printzii
Coelastrum probiscideum
Coelastrum pseudomicroporum
Coelastrum pulchellum
Coelastrum pulchrum
Coelastrum reticulatum
Coelastrum schizodermaticum
Coelastrum sphaericum
Coelastrum stuhlmanii
Coelastrum triangulare
Coelastrum verrucosum

Thanks Glen, I'm getting more comfortable with it now. One thing's for sure - I'm not one to jump to conclusions when it comes to ID.