Back In Time

Frez · Post by **Frez** » Mon Jul 30, 2012 8:09 pm

Here they are folks! Straight from the Eocene epoch and into your homes in all of their dark field glory! Presenting Moe, Larry and Curly! Also known as:
Trinacria solenoceros
Eunotogramm weissei
Auliscus oamaruensis
They have waited tens of millions of years for this moment. Give them a big round of applause!

Stacked with CombinZP
Thanks
Frez

CaptainFwiffo · Post by **CaptainFwiffo** » Mon Jul 30, 2012 9:19 pm

How many have gone through my swimming pool filter?

Charles Krebs · Post by **Charles Krebs** » Mon Jul 30, 2012 9:48 pm

Dang Frez... good to hear from you again, and see some nice new pictures!!!

I had to rub my eyes and check the date on the post to be sure someone hadn't bumped up a "golden oldie".

I see you are still playing with those old pieces of silica.

Frez · Post by **Frez** » Mon Jul 30, 2012 10:07 pm

Hey Charlie! It was awesome to see you're still here. I gotta love those diatoms. Somebody has to keep the old things in the mix.

I saw your honey bee foot and had no idea what it was. Pretty cool! There's a lot of talented people here.

Frez

Craig Gerard · Post by **Craig Gerard** » Tue Jul 31, 2012 12:50 am

Frez wrote:They have waited tens of millions of years for this moment. Give them a big round of applause!

Craig

Cactusdave · Post by **Cactusdave** » Tue Jul 31, 2012 3:15 am

Great to see a new post from you Frez. I don't think you've posted anything since I've been around on the Forum, but your reputation certainly goes before you. It's also nice to see some pictures of fossil diatoms, an enthusiasm (among too many

) of mine.

Mitch640 · Post by **Mitch640** » Tue Jul 31, 2012 4:41 am

Very interesting subjects and excellent images. I have 3 or 4 gallons of these things, but until recently, 40x was my most powerful lens. I am inspired to try again now that I have a 100x.

Where did you get your samples?

Frez · Post by **Frez** » Tue Jul 31, 2012 7:54 am

Mitch640 wrote:Very interesting subjects and excellent images. I have 3 or 4 gallons of these things, but until recently, 40x was my most powerful lens. I am inspired to try again now that I have a 100x.

Where did you get your samples?

Hi Mitch

3 or 4 gallons? How many diatoms is that?

All of these images were taken with a plan 40x 0.65 objective. The 100x is great for these subjects, but a 40x is fine for the larger specimens. These are from the Oamaru deposits in New Zealand. They can be purchased from Bill Daily at this link. His samples from Dunkirk are excellent and I'll post some examples later.
http://micrap.selfip.com:81/micrap.htm
He also sells a mountant called Zrax. Be sure to read the instructions before trying to mount your own.

Since mounting with Zrax, or other mountants, can be a little time consuming, the I want it now factor is lost. To avoid this I'm trying something new by making wet mounts with oil. The samples Bill sells come in small plastic vials that have the diatoms mixed with water. I take a small amount of this in a pipette and place it on a slide. Next I add some ethanol to act as a drying agent. Isopropyl would work too.

Just leaving the diatoms in the water and applying a cover slip doesn't work well as the water evaporates pretty fast. First I tried immersion oil, but even with low viscosity oil bubbles became trapped in the specimens. After some trial and error I settled on Cassia oil. This is a thin essential oil with a refractive index of 1.600 to 1.614 that does not evaporate. It's readily available on the web. Just add two drops to the slide, gently stir it around and drop a cover slip on it. The above images were taken with this technique. Of course the disadvantage is using an immersion objective as the cover slip will just slide around.

Good luck
Frez

Mitch640 · Post by **Mitch640** » Tue Jul 31, 2012 8:18 am

Thanks for the links and the explanation. On reading this, maybe I was doing it wrong. I just put some of this stuff I have on a slide and covered it with a coverslip, dry. It looked really, really small, and also, I got the sense that they were all broken into smaller pieces and rounded, as in eroded, meaning no sharp edges left. I am not sure where these samples came from, but I think it is time for another look.

Frez · Post by **Frez** » Tue Jul 31, 2012 9:50 am

If you have even 1 gallon of diatoms that were expressly prepared for viewing with a scope, it would cost a fortune. What you have are crushed diatoms likely for some kind of filtration system.

Frez

Mitch640 · Post by **Mitch640** » Tue Jul 31, 2012 9:57 am

No, these are food grade, for bulking up animal feed. As they work through the tract, they kill parasites. Not for microscope viewing, although I wanted to see what they were, so I took a look.

I just made another slide, and using a 40x phase lens in BF, I could see them quite well and none of them are whole. LOL Too bad, cause they are freshwater and obviously species I have never seen before. Very interesting and also millions of years old.