Microscopy Thread

[RobertK]

If these are eggs it's very interesting that they all have split the cell exactly once so far. Might be coincidence, but it could also be a hint that it's something completely different.

I agree, and am not saying these are eggs. I thought the other ones in the previous post might be be eggs. No idea what these are!

 

[RobertK]

Looking today at a small speck of brown film scraped from the glass. Mostly just a bunch of diatoms of different shapes - spindle, rectangular, triangular - but happily no dinos as seen in prior photo in post #140.

I did see some of these things mixed in with them - is this a type of diatom?

And then there was this odd little fellow. What is this? Reminds me of my dog, but he has only 4 legs!

Here's a video clip of it too:

 

[EnterName]

I did see some of these things mixed in with them - is this a type of diatom?

I would guess it's coralline algae.

The odd "dog" could be a marine Tardigrade. Tardigrades are really abundant and fascinating creatures. Some of them survive nearly everything Dehydration, extreme heat, extreme cold, starvation, exposure to outer space, ... They are insane

Cute Dog btw
I think 4 legs is an okay number of legs for Canis spp., but I'm not an expert

 

[EnterName]

@RobertK here is something similar:

I have looked a bit deeper into this, and it turns out actual coralline algae (Order Corallinales) are not the only ones that form these structures, so it's possible you are looking at something else that just grows in a similar fashion. I assume hobbyists would still call it "coralline algae" since it looks the same when it covers rocks and glass, but from a strictly scientific perspective these organisms might not be closely related at all. Actual coralline algae is a "red algae" (though the color can still differ), so it belongs to the "Rhodophyta", while actual green algae belong to "Chlorophyta". These organisms took different evolutionary pathways a long time ago.

Ulvella scutata (green algae), for example, can grow in similar patterns even though most people associate Ulvales with "sea lettuce". Similar growth can even be found in freshwater, like Pseudulvella americana, so I'm not even sure there's a lot of calcium involved like you'd expect from actual coralline.

Morphology and modern taxonomy (which cares more about ancestry than appearance) really hate each other sometimes.

 

[RobertK]

Thanks for the ID and info, @EnterName! A green alga makes more sense, as there are some other green algae (I presume) in that same photo and I'm not seeing any coralline algae on the glass yet in this new tank.

The other ID of a tardigrade appears spot on. I looked them up, strange but ubiquitous little creatures indeed. But I guess my analogy to a dog is not quite accurate, as their common name is "water bear"!