Selections From The Alabama Hills Deposit

Frez · Post by **Frez** » Thu Feb 28, 2008 10:01 pm

More fossil diatoms. All with a 100x objective and the Zetopan.

Frez

augusthouse · Post by **augusthouse** » Thu Feb 28, 2008 10:44 pm

Frez,
I found those images to be 'magnetic'! That third one really woke me up.
Your images finally encouraged me to learn about diatoms, forgive my ignorance. So I went to Wiki and the magical mystery tour continued...

http://en.wikipedia.org/wiki/Diatom

Craig

Frez · Post by **Frez** » Fri Feb 29, 2008 6:04 am

Hi Craig

Over the years I've managed to collect samples from various deposits. Often I'll get engrossed searching for a specimen of one certain species that is uncluttered by its surroundings and flat to the slide. It can become very obsessive, but finding it is rewarding.

Frez

bernhardinho · Post by **bernhardinho** » Fri Feb 29, 2008 8:00 am

Hi Frez

these pics are gorgeous!!!

Though I don't quite understand how or where you find the diatoms. Do I take from the term "fossil diatoms" that you find them in stone or rock samples? And then how do you prepare them for photography?

Curious wishes

Bernhard

Charles Krebs · Post by **Charles Krebs** » Fri Feb 29, 2008 10:49 am

These are beautiful Frez.

Are these from the state of Alabama (and not the Alabama Hills of California, famous locale for western movies)?

Jean-marc · Post by **Jean-marc** » Fri Feb 29, 2008 4:54 pm

Hi,

Beautiful interferential contrast !

JM

Frez · Post by **Frez** » Fri Feb 29, 2008 7:25 pm

bernhardinho wrote:Hi Frez

these pics are gorgeous!!!

Though I don't quite understand how or where you find the diatoms. Do I take from the term "fossil diatoms" that you find them in stone or rock samples? And then how do you prepare them for photography?

Curious wishes

Bernhard

Hi Bernhard

Diatom deposits can form when a body of diatom rich water dries up. Over millennia the sediment is compacted into rock. Diatomologists collect samples of these rocks and through the use of various acid baths and sieving techniques extract the skeletons which are known as frustules.

The sample is then ready to be mounted on a slide with a high refractive index mountant. I use Zrax.
http://micrap.selfip.com:81/micrap.htm
A solution of water and cleaned diatoms is dried on a cover slip. A drop of mountant is then placed on a slide and the cover is gently lowered on top of it, diatom side down. It is then allowed to rest on a hot plate on a low setting for at least 24 hours or until set. I have found that there is a specific setting that bubbles the Zrax causing the Toluene in it to evaporate quickly. Just a little too much heat and the cover will dance and make a mess of things.

Some of the most famous diatom deposits are found in Oamaru, New Zealand. A search in Google for Oamaru and diatoms can turn up some interesting results.

Frez

Frez · Post by **Frez** » Fri Feb 29, 2008 7:34 pm

Charles Krebs wrote:These are beautiful Frez.

Are these from the state of Alabama (and not the Alabama Hills of California, famous locale for western movies)?

Yes they are from Alabama Hills in Inyo County, CA. This is where Billy The Diatom frequently hung out.

Frez · Post by **Frez** » Fri Feb 29, 2008 7:43 pm

Jean-marc wrote:Hi,

Beautiful interferential contrast !

JM

Thanks Jean-marc. The middle image is done in IC. The top and bottom are in Anoptral phase contrast. The objective used for IC is a Reichert 100x plan with iris. The condenser is a .70 NA LWD. I was surprised to get this sharp of an image.

Frez