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"!

 

[RobertK]

Hi @EnterName,
I'm recovering from a dino outbreak of amphidinium and ostreopsis. Sand and rocks are looking much better now but there is a new brownish patch on the sand, which under the microscope predominantly showed these organisms. Is this a different dinoflagellate? Or a diatom?

 

[EnterName]

Hi @EnterName,
I'm recovering from a dino outbreak of amphidinium and ostreopsis. Sand and rocks are looking much better now but there is a new brownish patch on the sand, which under the microscope predominantly showed these organisms. Is this a different dinoflagellate? Or a diatom?

Hi Robert,

good to hear that your battle against those Dinoflagellates is making progress. What you are seeing right now should be diatoms

 

[Daniel@R2R Verified Admin]

Bumping this up for great info!

 

[EnterName]

Bumping this up for great info!

Thank you very much!

I will keep adding content, so this thread is very much still alive . Currently I'm looking into staining techniques, hoping to help with certain identification processes or simply improve visibility of things that might otherwise lack contrast.

I'm still very invested in the identification process of some Convolutriloba flatworms, and am trying to reach someone specialized on the topic to help me figure out if I have indeed found a new species, the current species description needs an adjustment, or if I have simply missed a detail.

I unfortunately have not received a response yet, but I'm sure I will find someone else who specializes in Acoels sooner or later that can help me out if I won't hear from them.

 

[EnterName]

Phytoplankton
(Tetraselmis suecica)​

Tetraselmis suecica is a flagellated phytoplankton that is frequently cultured as coral or zooplankton food. It's not as easy to culture as Nannochloropsis salina and N. oculata, but with the right approach even cultures in quite bad shape seem to be recoverable as long as there aren't too many impurities like other phytoplankton species or even zooplankton that preys on Tetraselmis. What may look like a crashed culture is in reality just a culture with mostly dormant cells that are waiting for the right time to grow and reproduce again.

(How I received the starter culture)​

While the starter culture I received certainly looks bad, a quick microscope investigation showed me that it was free of other unwanted organisms and the cells simply went dormant due to lack of water movement, light, and temperature changes during the transport.

Common Name	"Phyto" / Phytoplankton / Tetraselmis
Classification	Tetraselmis suecica
Verdict	Beneficial (Coral and Zooplankton food)
Size	≤ 25μm
Found	Phytoplankton Culture
Rarity	Won't survive for long in most tanks, needs to be added

My first batch already came out quite dense and deep green with a lot of movement as you can see:

(T. suecica at 100× and 630× magnification)​

So if you ever try to culture Tetraselmis, don't get discouraged by what looks like a crashed culture. The cells simply need some time to adjust to the parameters again and shaking the culture to encourage the cells to start swimming again is the only "trick" you need to know about these guys.