First try at darkfield with new E200

pwnell · Post by **pwnell** » Wed Sep 28, 2011 11:21 am

I just received delivery of my Nikon E200 microscope, and I must say it is a huge step up from what I had before. I got the phase contrast condenser and phase contrast plan objectives. Keep in mind this is the first time I ever played with anything other than brightfield illumination.

I have a Nikon D90 tethered to the trinocular head.

Here is a photo of a small rotifer I believe from my reef aquarium, at 20x, using darkfield. Have I done it right? It is a single frame - no stacking (yet):

Planapo · Post by **Planapo** » Wed Sep 28, 2011 12:51 pm

Waldo,

I'd say you have done very well with your new equipment, especially as it is your first go with it!

As to the ID of your critter: Did you see any typical rotifer features? Being not that much familiar with rotifers, particularly not with marine ones as there are only few species inhabiting saltwater, I could be mistaken, but the animal you have photographed here does not look very rotifer-like to me. From what I see in your photo, I'd think more of a crustacean.

--Betty

jc maccagno · Post by **jc maccagno** » Wed Sep 28, 2011 12:55 pm

Nice picture but definitely not a rotifer...most likely a crustacean

Best wishes

John

pwnell · Post by **pwnell** » Wed Sep 28, 2011 12:59 pm

Planapo wrote:Waldo,

I'd say you have done very well with your new equipment, especially as it is your first go with it!

As to the ID of your critter: Did you see any typical rotifer features? Being not that much familiar with rotifers, particularly not with marine ones as there are only few species inhabiting saltwater, I could be mistaken, but the animal you have photographed here does not look very rotifer-like to me. From what I see in your photo, I'd think more of a crustacean.

--Betty

Quite possible... It looks like a copepod without the two spiny things at the apex of the abdomen, but the red triangle feature on its thorax is very different from my copepods. This has been identified as a rotifer by another reef aquarium enthusiast so it is quite possible he made a mistake.

I do have a bottle of rotifers and they are TINY - even under 40x magnification I just see a small circle and some hairy "legs" which it uses to swim with.

Sorry for my horrible lack of biologically accurate descriptions - I am an engineer, not a biologist

pwnell · Post by **pwnell** » Wed Sep 28, 2011 2:40 pm

With my highest objective I currently have (40x) this is the best I could do with a rotifer:

Mitch640 · Post by **Mitch640** » Wed Sep 28, 2011 3:35 pm

That's not a rotifer either. And 10x ought to show them fairly large, 20x will fill the frame.

Google Rotifer for a better selection of different rotifers.

pwnell · Post by **pwnell** » Wed Sep 28, 2011 3:42 pm

Then I am confused! I purchased a bottle of Living Reef Live Zooplankton Rotifers, and that was the only living thing I found in the bottle.

Hmmm snake oil? I'll do my research better next time, thanks.

Mitch640 · Post by **Mitch640** » Wed Sep 28, 2011 3:48 pm

Google is one of the best ways to see what a microbe is. People here can either tell you exactly, or at least point you in the general direction, then go to Google and search for it. They have thousands of images.

Wim van Egmond · Post by **Wim van Egmond** » Wed Sep 28, 2011 11:36 pm

A very nice image. I hope the new equipment will give you a lot of inspiration!

It is certainly not a rotifer. I think it is an early copepod stage. And when it is not that perhaps an isopod or orther crustacean larva.

Wim

phytoplankton · Post by **phytoplankton** » Thu Sep 29, 2011 1:34 pm

pwnell wrote:Then I am confused! I purchased a bottle of Living Reef Live Zooplankton Rotifers, and that was the only living thing I found in the bottle.

Hmmm snake oil? I'll do my research better next time, thanks.

There does seem to be quite a few companies cashing in on the reef supplements craze. Though that doesn't mean that this is one such example. They may merely have died after depleting their food.

As for your first image, it is a good darkfield shot. It definitely appears to be some sort of crustacean. I don't want to alarm you but if this was in my aquarium I would try to find an expert and positively ID it. It could be a parasite or it could be something benign or even beneficial - it doesn't hurt to find out if you can.

pwnell · Post by **pwnell** » Fri Sep 30, 2011 9:06 am

According to this site it is a Harpacticoid copepod, which should be highly beneficial to the tank.

http://reefkeeping.com/issues/2003-02/nftt/index.php

Planapo · Post by **Planapo** » Fri Sep 30, 2011 10:34 am

Thanks for the follow-up.

Yep, Copepoda that was my initial assumption too. To be more 'specific'

, it could well be a species of the genus Porcellidium or another closely related genus of the Porcellidiidae.
Mostly one should be cautious with a too specific ID just from a photo, without having the specimen under one's own (stereo-)microscope.

You may want to google for pictures of copepods of the genus Porcellidium and compare them to your specimen.

--Betty

Charles Krebs · Post by **Charles Krebs** » Fri Sep 30, 2011 11:40 am

Waldo,

Nice to see you are up and running.
A good page to have bookmarked is:
http://starcentral.mbl.edu/microscope/p ... azorganism

(Home page: http://starcentral.mbl.edu/microscope/p ... itle=index )

Might not be all that helpful looking at marine tank specimens, but overall a great resource.

pwnell · Post by **pwnell** » Fri Sep 30, 2011 11:44 am

Charles Krebs wrote:Waldo,

Nice to see you are up and running.
A good page to have bookmarked is:
http://starcentral.mbl.edu/microscope/p ... azorganism

(Home page: http://starcentral.mbl.edu/microscope/p ... itle=index )

Might not be all that helpful looking at marine tank specimens, but overall a great resource.

Woa! That is exactly what I was looking for... As I said I am not a biologist, this is to keep me sane from my real work, so it is really great to find a reference site where I can start looking for identifications.

I am using the D90 currently, though I am struggling with mirror induced vibrations as I do not think the 1 second exposure delay is working well enough. So I just placed an order for that DD20NLT to use with my 1Ds Mark III as that has a proper MLU function and I do hope that, combined with the extra weight of the 1-series body, will reduce the vibrations.

Mitch640 · Post by **Mitch640** » Fri Sep 30, 2011 11:50 am

I had the MkIII when I got my microscope. It's not the mirror that's the problem, well, not only the mirror. It's more the shutter than anything else. They don't call it the sausage slicer for nothing.

I soon sold mine for a T1i and all my vibration problems just melted away. I do wish I had bought the T2i instead though, as it has full manual video mode. Charles has a T3i and I have not seen anything as good at video or stills as that camera. The price is great to.

First try at darkfield with new E200

First try at darkfield with new E200

re darkfield