Microscopy Thread

[EnterName]

Let me preface this by saying that I'm not really happy with the quality of today's post.
I have not yet set up my microscope for reflected light microscopy which makes larger specimens a challenge. I had to use dark-field and focus stacking and still didn't manage to get that nice crisp image I was looking for.

This Spirorbid worm (see common hitchhiker guide section 3) was taken from my filter sump's glass wall:

(Spirorbis sp.)​

I still made an DIC recording so you can see what hides in the tiny little white spirals that you probably can find all over your tank. Again, it looks like Cthulhu's offspring just like post #24:

(Spirorbis sp. emerging from its shell)​

 

[EnterName]

Today I have taken some time to look at another sponge. These white "root-like" growths are found in many tanks sooner or later and sometimes cause some concerned questions here on Reef2Reef. It might belong to the genus Clathrina, but I'm not very sure about that. Either way, they are totally harmless filter feeders

(Sponge in filter sump)​

Under the microscope we can see the sponge's "Spicules" that are acting as its skeleton. In this case we are looking at "Triactines" (three-rayed spicules) that are calcium carbonate (CaCO₃) based. I was able to verify this by adding some acetic acid which slowly dissolved the spicules. Silicate based spicules would not have reacted.

(Calcareous Triactines and sponge tissue)​

I really love how they look when using polarized light. They suddenly appear colorized through a physical phenomenon known as Birefringence. You can also see sponge's cellular layer which is a whole rabbit hole in itself.

(Birefringence effect on spicules caused by polarized light)​

The beige ovals and small granular bits in the previous image are far more interesting than they might appear at first. After squishing the sample to spread the cells throughout the slide you can see that these cells have flagella and therefore can move quite a little bit on their own.

(Flagellated cells of the sponge)
​

Sponges have insane regenerative abilities which you can see live under the microscope. The cells will actively "find each other" and clump together again forming piles known as "aggregates" (you can see a few in the video already). Then they will start to form a new sponge where different cell types perform different tasks. I highly recommend reading a bit about Sponges and their regenerative capabilities, it's absolutely fascinating.

 

[EnterName]

Another day, another sponge! This time it's a Sycon sp. better known as Pineapple Sponge . They are absolutely harmless and even beneficial to your tank as you will see.

(Small Pineapple Sponge in sitting on the glass in my filter sump)​

Similar to the sponge I posted yesterday (Post #82) these sponges have calcareous spicules, but most of them are very long "spears" instead of three-rayed spicules.

(Long spear-like spicules on the outer layer of a Sycon sp.)​

A lot of debris is stuck in these spicules which makes sense considering that these sponges are filter feeders and clean your tank. In contrast to the sponge from yesterday they have a very obvious "Excurrent pore" where water exits the sponge once it's filtered. It's basically just a hole at the top of the sponge with another set of spear-like spicules:

(Excurrent pore "Osculum" of a Sycon sp.)
​

They have the same astonishing capability of fully regenerating from a few cells when injured. In the first section of the video down below you can see their cells wiggling around with flagella building cell-clusters ("aggregates") to form new sponges and recover.
As you have already seen this in my last post, I decided to focus mostly on what appears to be amoeba in between the sponge cells and a ciliate feeding on residues of a diatom found in the sponge's spicules.