MicrobeHunter.com Microscopy Forum

Red Sea sand is rich in colorful minerals (granite rocks), foraminifera and other shells and things. The collected sample underwent wet sieving, washing with tap water and distilled water, then drying in an oven at 170C for 1h. The narrow grain size range makes a thin, uniform layer in the Petri dish, and facilitates the treasure hunt. Interesting forms were picked out at the stereoscope, under 10X total magnification, using a wetted fine-tip painter's brush, or even better, a fine syringe needle (size 23G, 0.6mm diameter). Larger grains (>1mm) were easily picked with jeweler's forceps. I mounted them in chamber slides, where a 13mm-diameter, 2mm deep circular chamber was created by punching out a 2.5cm wide, 2mm thick double-sided adhesive tape (a well-known trick). The tape is affixed on top of the slide, and the chamber can be topped with a square coverslip. Such a chamber is almost too thick for the working distance of my Zeiss 6.3X Plan objective, so a thinner tape might be better. The grain forms are mounted within the chamber onto a thin layer of PVA-based office glue.

Epi-illumination on the compound microscope was achieved with two 5mm super-bright LEDs, diagonally directed below the objective front lens. This was a cheap and space saving arrangement for the 6.3X objective. The condenser top, under the stage, was covered with black velvet cloth, rather than black cardboard. Photos were taken with Canon camera. Stacked with PICOLAY.

Among the grains are white flat porous fragments and discs (photos 3, 4). Pore size is 8-35 microns. Are they coral skeletons? There is a nearby reef. Help with identification - welcome!

Forams were white or yellow or beige (a black one escaped my forceps). Dilute citric acid dissolved the calcium carbonate, so the white form disappeared, but the yellow form left over some thin brown-black strands and thin membranes, presumably organic. I might pre-clean the sample with peroxide.

(Continued) Note: Photo 5 was taken under trans-illumination through the Ph3 phase contrast position of the condenser, the 6.3X Plan is non-phase objective. So, it is darkfield, the aperture condenser was closed to illuminate only the center of the FOV.

Nice work ... and your "(2) Sample of photo 1, USB camera on sterescope, 10X, field width 10mm.jpg" is very effective.

MichaelG.

Thanks MichaelG.

A superb set of crisp images and a very nicely put-together presentation.
This is a great example of what's 'out there' for those with a little curiosity and a will to follow it up!
Your description of the processing and 'scope techniques used is very interesting and informative, thanks for a very nice post indeed

Look forward to more of this quality.

Thanks John B! More ideas about the sand are being pondered...

Hi Doron,
thank you for posting these beautiful images! I like the trans illuminated images best with it's warm glow.

Sand is a nice topic to demonstrate the value of microscopy - one gets a better understanding of the world around without much effort. I like to look at beautiful things and sand offers a lot if observed in detail.

Foraminifera are useful in scientific sense as they allow to determine the change of coast lines over the time.

Bob

Very nice post and pics, thanks! I've been looking at local beach sand under the stereo scope too. I need to keep experimenting. Here is a sample.

The clear is quartz, pink is garnet (some with inclusions), black are iron/metal oxides. Brown looks like root beer soda bottle:)

MicroBob wrote:...Foraminifera are useful in scientific sense as they allow to determine the change of coast lines over the time.

Thanks Bob! I am reading that Foraminifera are now considered important indicators and sensors of global climate changes, since their building of the shells ("tests") depends on CO2 level in the oceans, on the marine water acidity, etc.

geo_man wrote:The clear is quartz, pink is garnet (some with inclusions), black are iron/metal oxides. Brown looks like root beer soda bottle:)

Thanks geo_man. Agreed about the root beer. Luckily my samples appear to be devoid of anthropogenic articles.
Here is a way to isolate iron oxides: I keep my pieces of neodymium magnet within a plastic test-tube, for safety reasons, since they are very strong magnets indeed. I wiped it along the heap of sand, and, lo and behold, several 3mm size grains, probably of iron oxide (magnetite), were attracted to the test-tube and attached to it, so picked out of the heap. An "ordinary" magent of the same size is not sufficiently powerful to extract the magnetite from the sand.

Thanks Hobbyst46, i will look into that!!

And of course, forms can be used to date ancient strata.

Beautiful foram images, keep 'em coming!

Thanks KurtM. I am still working on it...

Changes to illumination and chamber:

I thought that a complete 60mm-diamater LED ring, placed around the objective, would provide better epi-illumination of the sand and forams, and experimented. Yet, the pair of 5mm diameter, super-bright warm-white LEDs, symmetrically positioned at opposing points and beaming obliquely, better accentuates the patterns on the grain surface. Here is a scheme of the setup. Each LED is supported by a small ramp (shown in green), made of aluminum plates, and is affixed to the sloping plate with adhesive, sticky tape, clay etc. The ramps are laid on the stage and can be moved and nudged for optimum illumination. Primitive, yet flexible. The condenser top lens is shaded with black velvet cloth

For the chambers, I now use 1mm-thick double-sided adhesive tape. The chamber is thin enough for easy observation with my 6.3X/0.16 Plan and 10X/0.30 Neofluar objectives. A coverslip is used to protect both the objective and specimen.

Mica fragments:
I had fractionated my sample of sand by sieving. The finest grain fraction, of size <0.7mm, contained golden, semi-transparent shining platelets, which I think are Mica. They are thin, flat and very weakly birefringent. Below are photos of some of them, of sizes 400/900 micrometer, recorded with 10X/0.30 objective and illuminated either by the oblique epi-LEDs, or by brightfield+polarizer. Post processing: Resized, uniformly cropped and tweaked contrast.
Comments are welcome.

(continued)

More about the mica platelets in the sand
I was curious to know if treatment of the Red Sea sand with an oxidizer will change the color, or even disintegrate, the Foraminifera. Often, Foraminifera are not pure inorganic shell but contain proteins, even when are they are motionless and "dead". So I boiled a sample of the sand in hydrogen perxide for an hour. No dramatic change was observed. The Forams remained white or beige as before. Yet the mica platelets, which previously were scattered among the other grains, formed clusters. See in photo 16, a "hill of bronze/gold". I suspect that the oxidation cleaned them so well that they now stuck to each other due to surface forces. Simply boiling the sand in water did not produce this effect.
I find granite rocks really fascinating. Photos 17 and 18 are small examples of selected grains, that are larger than the H2O2-treated grains. Just to give the idea, they are single images. All photos are taken with my Zeiss microscope and Plan 2.5X and are similarly resized, not cropped.
Illumination was done with the 2 top LEDs, as shown in the above drawing.

Some more Foraminifera. Imaged with my Zeiss microscope and 2.5X or 6.3X Plan objectives. Resized, cropped by about 100%, contrast tweaked, background slightly cleaned.

Top LED illumination. To create a black background, the condenser under the stage is covered with black velvet cloth.

Notes:
Photo 22 is not a Foram in my opinion, it looks more like a sponge (??). Resembles a porous Asparagus stem.
Photo 23, that looks like a man-made porous disk, is - I think - a Foram or part thereof. Similar forms are mentioned in the literature.
A stack of the disk looked worse than a single image, the disk is fairly flat.

This is an exceedingly interesting thread, well done sir, thanks for posting!

The "zebra stripe" foram in 21 is spectacular. The last two are mysteries to me also - I have found similar objects in beach sand from various locations in the USA.

Very nice images, Hobbyst46!

May I suggest use an objective hood (wrapped tightly around objective lens) made of Vellum paper for better difdusion? Even think office paper will work better than not having any diffusion.

In you photo #19, I can see two hot spots, perpendicular to them, I can kind of see two darker areas too. If diffusion takes away too much light, I would suggest adding 1-2 more LEDs. Or simply use those tiny Maglite Solitaire LED flashlights (powered by AAA batteries).

Better still, use a half ping pong ball (drill a hole for objective to see through) and 2-3 speedlites. Charles Krebs uses that kind of set-up and produced many award-winning microphotographs.

In US, one can also buy miniature "beer pong" balls about half the size of a regular ping pong ball. I bought some from my local Kroger (located at Autumn Creek Village, Texas 77546, in case Kurt wants to buy them). Smaller diffusion ball that matches subject size exactly will provide more even diffusion and save working distance.

Thanks KurtM and zzffnn for the kind words.

@zzffnn, @MicroBob:
I thought that the highly directional LED beams will create oblique effects. Yet your comments are inspiring. So with the DIY- LED ring and a diffuse light cloth (details will be given if it works...) I will try another illumination as well.

BTW, I found a site with identified Red Sea Forams. Coming up next.

Hi Doron,
very nice images again with very creamy colours!
I liked you glowing transmitted light image #5 very much too.

Here are SEM images of foraminifera: http://www.mikrohamburg.de/HomePalaeo.html

Here is a site with identified foraminifera, there is also a map of the locations: http://www.foraminifera.eu/locality.php They do nothing else!

I don't know how difficult it is to come close to a precise identification. One problem will be that some have been ground on the beach sand more than others.

Bob

This is a great thread. Nice collection of subjects. Keep your eyes open for micrometeorites. They have to be there somewhere, although abraded by the sea they may be hard to distinguish.

Fantastic 'beach combing' you share with us in forum...thank you, hobbyist46. I have beach sands sent to me from a microscopist in Abelene, Texas/US...( thank you Mike C.), and I have chamber slides sent to me from a microscopist in Italy (Milano, Italy...thank you). I enjoy your protocol for 'shell picking' these..err: 'microfossils'? these err: seasonal husks of current life forms.

I wonder just when beach sands are deemed to hold 'microfossils', rather than current biomes shells? Does digging deeper into a beach sand bank offer ancient forams? This a cheerful thank you, hobbyist 46, for this thread you share! Charlie guevara

You can make your own micropaleo or plummer blank slides..

http://www.microscopy-uk.org.uk/mag/art ... Slides.pdf

BillT

@BillbillT
Many thanks, BillbillT, for the link. Right now I am just punching out a 14mm hole in a double-sided adhesive tape, attach it on top of a glass slide and cover with a regular cover-slip. The multi-cell versions are worth trying.

apochronaut wrote:This is a great thread. Nice collection of subjects. Keep your eyes open for micrometeorites. They have to be there somewhere, although abraded by the sea they may be hard to distinguish.

Many thanks, Apochronaut.
At first I thought that you meant iron oxide particles, which I indeed found, using a strong magnet. But nowI understood that I should look for startdust, thanks for the great idea - I most certainly will try !

charlie g wrote:...'beach combing'... protocol for 'shell picking' these..err: 'microfossils'? these err: seasonal husks of current life forms.
I wonder just when beach sands are deemed to hold 'microfossils', rather than current biomes shells? Does digging deeper into a beach sand bank offer ancient forams? This a cheerful thank you, hobbyist 46, for this thread you share! Charlie guevara

Thanks, charlie g, very cheerful indeed. Actually it is sand sieving; the sand was dug from the shallow water line, the border between dry and wet zones; the tide is very shallow on the Red Sea, especially in the Gulf of Aquaba. The top layer was collected, that is a depth of 0-20cm. In all likelihood, seasonal life forms, and not fossils. I do not know if and how fossils at such zones (or anywhere else...) are located.
BTW - beach combing reminds me of the process of "Comb The Desert" in the movie Spaceballs, and how it was literally done...

billbillt wrote: http://www.microscopy-uk.org.uk/mag/art ... Slides.pdf

Thanks for the link. BillT ... I had missed that one.

MichaelG.
.

P.S. Just remembered this delightful little video
https://youtu.be/JLSa8cGJixQ

"Comb The Desert" in the movie Spaceballs"

Maybe you are using the wrong type "rake"..LOL..

The Best
BillT

A found a small web site: http://www.dafni.com/Foraminifera/Galle ... forams.htm (it is blingual)
that (tentative identification!) shows some of the benthic foraminifera that I have found in the Red Sea sand and posted photos of them above.
I was glad to find that the nice porous disks are indeed forams. Here are the relevant genera/species as shown on that site:

charlie g wrote: Does digging deeper into a beach sand bank offer ancient forams?

Hi Charlie,
foraminifera can be used to research the movement of coast lines. When you bore a hole with a hollow drill you can part it in layers, clean it ( I think with H2O2) and look whether and which foraminifera are there.
Our microscopy group has a small offspring that works on micro palaeontology, mainly foraminfera. They once got drill cores from the river Elbe in Hamburg and made a profile of the foraminifera in the different layers. This might be very interesting, especially with the raising water levels today.

Bob