Microscopy Thread

[christinna77]

2000x? With a light microscope? With very good objectives you can make 1000x work and have images of reasonable quality, but everything above will be very dark, and you won't be able to resolve more detail than what you were previously seeing with 1000x. The wavelength of visible light limits the amount of detail you can actually resolve.

I know microscopes theoretically can reach 2000x etc. by using a 20x eye piece and 100x objective, but as previously stated you won't get more detail, just a darker image, with less contrast and no additional detail.

It was this one: https://www.amazon.ca/dp/B0BYYY51HJ. 25x eyepiece, a 40x objective and a 2x lens. You're right about the image quality - I almost never use the 40x objective because even without the 2x lens, it's not great. I also have to get way too close to the slide, pretty much touching it to see anything. I think that's actually the only image where I tried to capture it with the 40x objective.

 

[EnterName]

It was this one: https://www.amazon.ca/dp/B0BYYY51HJ. 25x eyepiece, a 40x objective and a 2x lens. You're right about the image quality - I almost never use the 40x objective because even without the 2x lens, it's not great. I also have to get way too close to the slide, pretty much touching it to see anything. I think that's actually the only image where I tried to capture it with the 40x objective.

It's pretty normal to get very close to the cover glass with 40x, 63x, and 100x objectives, but a 40x one should not be touching the cover glass. Maybe you accidentally added two cover glasses at once? They sometimes stick together making it hard to differentiate if you have one or two in your hand. Another possibility would be that they are designed to be used with immersion oil, but this should be noted in the instructions or even better on the objectives themselves. To get the cover glass nice and flat on the slide you can absorb excess liquid by using a piece of paper towel that you hold closely to the edge of the cover glass.

With a better scope (and better objectives) the loss of contrast should change quite noticeably, but it's really difficult to find a scope for around $2000 that's good enough to justify the price while also offering ways to upgrade sooner or later. That's why I can't simply give you something you should buy sorry

 

[EnterName]

Euplotida Ciliate
(Euplotes sp.?)

Note: If you are using the app you might need to switch to a web browser to be able to see the video(s).​

I'm currently playing around with the video editing software to improve the quality of my videos. This time I ensured the ciliate stays in the center of the frame which makes observing it easier.

(10x63 PL APO Immersion-Oil Objective Recording)
​

I purposefully shifted the focus around all the time so the little "legs" (ciri) as well as the ciliate's body are in focus from time to time.

​

Common Name	Ciliate
Classification	Order: Euplotida, Genus: Euplotes?
Verdict	Harmless/Beneficial
Size	≤ 160μm
Found	Detritus
Rarity	Common

 

[EnterName]

Aiptasia/Exaiptasia
(Family Aiptasiidae)

Note: If you are using the app you might need to switch to a web browser to be able to see the video(s).​

This might be the first time I didn't feel bad for accidentally squashing a sample
The little anemones commonly called "Aiptasia" are pretty much the worst thing that got ever introduced into my tank by accident.

I'm not yet 100% sure, but I think there are multiple species or at least strains that cause trouble in reef tanks. Exaiptasia pallida and Exaiptasia diaphana might be the ones that are actually present in our tanks, but there may be more.
Either way, some are really hard to get rid of as they spread aggressively, while others appear to be quite straight forward to deal with. Unfortunately I got really bad ones, which only my Copperband butterflyfish was able to save me from. He can't reach my filter sump though, so I found a little Aiptasia anemone there.

(End of a tentacle showing cnidocytes and zooxanthellae)
​

The cucumber-shaped things are cnidocytes which corals use to sting whatever causes them trouble. If you take a look at post #1 you can see a clearer image of cnidocytes of another coral. They are filled with a toxin-loaded string called cnidocyst that shoots out and injects toxins in whatever activated them. (There are actually a few activated ones as well in the video). The brown-ish blobs are zooxanthellae (Symbiodinium sp. dinoflagellates) which are the reason why corals can make use of photosynthesis.

Common Name	Aiptasia
Classification	Aiptasia sp. or Exaiptasia sp.
Verdict	Dangerous pest
Size	Usually ≤ 5cm (2")
Found	Coral frags, Rockscape
Rarity	Common hitchhiker

​

Aiptasia can reproduce by fragmentation like many anemones, but they are much simpler which allows very small fragments of the pedal disk to fully grow into a fully functional anemone (which would mean tentacles do not grow into new anemones). I hope to find one of their planula larvae as addition to this thread. Apperently some Aiptasia larvae can actively hunt copepod nauplii (see [2]).

(I used the wrong DIC prism but I still like the recording of a ripped of tentacle moving in circles on its own)​

The cnidocytes are very large and appear to be half the tentacles width. Maybe that's the reason why Aiptasia have such an incredible strong sting and can kill other corals so effectively?
The whole tentacle is covered in some sort of cilia which allows it to swim a bit on its own and in this case in a circle.

[1]: https://www.reefaquarium.com/2013/aiptasia-anemones/
[2]: https://www.pnas.org/doi/10.1073/pnas.2311872120

 

[EnterName]

Unidentified Hydrozoa
(Order: Anthoathecata?, Suborder: Capitata?)

Note: If you are using the app you might need to switch to a web browser to be able to see the video(s).
​

I noticed some strange stuff on the back wall a few days ago and decided to take a closer look.

(Back wall with weird "growth")​

I have no idea what it could be. First I though it to be a bunch of hydroids like shown in post #80...

Common Name	Hydroids
Classification	Order: Anthoathecata?, Suborder: Capitata?
Verdict	?
Size	≤ 1mm (0.04")
Found	Glass wall, ...?
Rarity	?

​

...but a closer look told me it was something else:

Note: The first video has 4 sections:

• Phase 1 (x630) - Time: 00:00​
• Phase 2 (x400) - Time: 00:11​
• Phase 3 (x400) - Time: 00:22​
• Phase 3 (x630) - Time: 00:33​

On the next day I found a specimen that wasn't buried in detritus as much giving me chance to see both anterior and posterior end:

Under polarized light (PL), explanation below, you can see how much movement there is within its body

(Polarized Light Microscopy of the specimen)
​

In the video above I used two polarizers to show only very specific sections of the specimen. Imagine light as waves that vibrate in all directions. The first polarizer acts like a filter that only lets through light vibrating in one direction (e.g. up-down). When this polarized light hits a second polarizer rotated 90° (now filtering only left-right vibrations), all the light gets blocked. They're perpendicular, so nothing passes through.
If something between the polarizers changes the vibration direction of the light by rotating it slightly, some of that light can pass through the second polarizer. This is what happens in the video: certain parts of the specimen rotate the light's vibration, so they light up against the dark background.

(Another close up)​

 

[EnterName]

Identification Progress?
(Post #125)​

Yesterday I posted photos of an unidentified specimen I hadn't seen before. I managed to find what looked like eggs, an early larval stage, and a more developed stage that might be the adult organism. At the time, I had no idea what I was looking at.

Since then, I found a digitate hydroid in my filter sump and took some recordings to add to the dedicated digitate hydroid post #61 (page 4). Hydroids have distinctive cnidocytes (the stinging cells used to capture prey), and some of these cells are noticeably larger and rounder than the ones found on corals. I hadn't examined them up close before, and they stuck in my mind afterward.

(Cnidocytes of a digitate hydroid)​

Looking back at the unidentified specimen from yesterday, I noticed very similarly shaped cells in the videos, including some smaller "activated" ones. That gave me more confidence that these are indeed cnidocytes.

(Cnidocytes of the unidentified specimen)
​

This points to some kind of Cnidarian, most likely a Hydrozoan. Scyphozoa ("true jellyfish") don't seem to fit here, and while Anthozoa (the group corals belong to) is another possibility, the shape of the cnidocytes doesn't really match what you'd expect from an Anthozoan.

There are many different types of nematocysts (the structures inside cnidocytes) [1], and some are more typical of Hydrozoans while others show up more often in Anthozoans. I'm not entirely sure, but I believe these are Stenoteles and/or Euryteles, which are more common in Hydrozoa than Anthozoa. That further supports my hypothesis that this is a hydrozoan.

It also turns out that having cnidocytes concentrated in a swollen knob at the tip of a tentacle isn't very common. That narrowed things down quickly to almost the only order (Anthoathecata) and suborder (Capitata) [2] where this feature occurs.

I will keep searching, maybe I can narrow it further down to the genus.

[1] https://www.researchgate.net/figure...-distribution-of-spines-on-the_fig1_238337656
[2] https://en.wikipedia.org/wiki/Capitata

 

[EnterName]

Flatworm
(Convolutriloba sp.?)

Note: If you are using the app you might need to switch to a web browser to be able to see the video(s).​

Usually I enjoy spotting new critters in my reef tank, but since I'm already considering treating the relatively harmless Acoel flatworms in my tank (see post #85 on page 5), I was definitely not thrilled to find this one:

(Unidentified flatworm on a microscope slide)
​

I'm not entirely sure it's a "bad" species, since it doesn't quite match Convolutriloba retrogemma (the Red Planaria flatworm), but it may still belong to the same genus.

Common Name	?
Classification	Order: Acoela? Genus: Convolutriloba?
Verdict	Unknown, possibly dangerous
Size	≤ 6mm (0.24")
Found	(This specimen was found on the glass near the substrate at night.)
Rarity	Likely a pest. Must be introduced into the tank by accident.

(Another video of the same specimen)
​

Convolutriloba flatworms have red pigment cells that you can also see in this specimen under the microscope. I'm not fully convinced it's a Convolutriloba species yet, since it doesn't quite match any of the images I've found so far (see [1] below). Note that the posterior end can look quite different when the flatworm is reproducing asexually, which it does by growing new flatworms on its posterior lobes.

(Dark field recording of the same specimen at 100x magnification)
​

At higher magnifications, you can clearly see the red pigments and the symbiotic algae:

(×630 recording showing the red pigments and green symbiotic algae)
​

It's a shame that I'll most likely have to treat them, since they're absolutely stunning under polarized light:

(Flatworm under polarized light)
​

[1]: https://alchetron.com/Convolutriloba

 

[christinna77]

Caught my emerald crab spawning at around 3am today! Managed to scoop up one of the larvae and get it under the microscope before safely returning it to the tank :)

 

[EnterName]

Caught my emerald crab spawning at around 3am today! Managed to scoop up one of the larvae and get it under the microscope before safely returning it to the tank :)

That's so cool! Thank you so much for sharing!

 

[EnterName]

Since starting this thread, I've updated many of my posts with more images, videos, additional info, and better quality where possible. I recently got new high-end objectives, and I'm now waiting for a new camera to arrive, which should improve quality even further.

If you haven't checked out my older posts in a while, I highly recommend going through them again to see what has changed.

There are posts about:

• Algae (Post #8, #60, #69, #103),
• Ciliates (Post #93, #100, #123),
• Corals (Post #50, #124),
• Crustaceans like Isopods and Copepods (Post #11, #102, #106),
• Cyanobacteria (Post #52),
• Diatoms (Post #1, #16, #91),
• Dinoflagellates (Post #1, #3),
• Hydroids (Post #51, #61, #80, #125),
• Nudibranchs (Post #101),
• Sponges (Post #6, #68, #82, #83),
• Worms (Post #4, #12, #24, #81, #85, #92),
• and some unidentified specimen that could use your help (Post #12, #39, #84, #94)

Here is the most recent video of a Flatworm under polarized light:

 

[RobertK]

Hi, can you please confirm this is amphidinium? It is growing as a brown layer on my sand for the last week or so. Photo and video attached. Sorry for the image quality, this was taken with an iPhone camera through a 50-year-old microscope that I don't even know how to use well. Thank you!