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Posts by JK about Microscopic matters.

Posted by on in Microscapes

In an earlier post I asked why certain diatoms moved when they had no need to search for food and no need to find a partner to reproduce. A recent enquiry to the 'Amateur Diatomist' website has resulted in this very informative reply:

"Lots has been written about the mechanism of diatom motility but little about why they might need to move. Whilst I am not qualified to explain all the reasons for their behaviour a couple of observable examples might suffice to set you on the right track....

Consider the episammic (living on sand) or the epipelon (living on mud) species where their habitat is governed by the tides. When the tide is in the diatoms can be found on the surface of their chosen substrate, when the tide goes out they are found within their substrate. They have moved to ensure they do not dessicate. Another example are those species found living on rocks in streams. They coat the upper surface of, say, a pebble. Should a storm suddenly cause the flow to increase to such a degree that it turns that pebble the diatoms will move to upper surface when things quieten down. This latter example can be observed by turning a colonised pebble by hand and returning the next day.
I hope these simple examples provide you with an answer (at least in part). Steve."
For anyone interested in diatom studies you'll find lots of useful information on the Amateur Diatomist website. www.diatoms.co.uk
Tagged in: Diatom Environment
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Posted by on in Microscapes

The spring collection of diatoms from Midgleden Brook show no significant changes to the diatom populations previously surveyed. Site 1 is the least populated, with specimens being primarily naviculoid (boat-shaped) and generally quite small. Site 2 is definately the most populated, with the greatest number of species and sizes ranging from small to very large. Site 3 results lay somewhere between the other two sites.

This trend is reflected in the results of the invertebrate study which also shows Site 2 to be the healthiest of the three sites. However, the recent loss of specimens in the invertebrate populations is not reflected in the diatom study. Whatever it was that affected the invertebrates it has not had any noticable effect on the diatoms.

Fascinating stuff. Cheerio for now. JK cool


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Posted by on in Microscapes

The diatom samples collected a couple of days ago by Nettie and Wal bring an end to the preliminary study and, hopefully, I'm now organised enough to begin the study proper.

I've just received (today) a new lens for my microscope which gives me x600 magnification (images to date have been x400) so future images will be more detailed and therefore more useful. I've also been studying a couple of new text books that have prompted me to make some small adjustments to my working practices. The delay in the start of the proper study will also give me an opportunity to practice with my x1000 (oil immersion) lens which is a procedure I've never done before. Fingers crossed for that.

Having said all that I'm pleased to announce that I can now answer some rather obvious questions, with equally obvious answers, as well as offering some tentative suggestions as to what's going on with the diatoms of Midgelden Brook. So, are there diatoms in the brook and can we find them? Yes to both. Are there a few species present or many? Even with my limited knowledge I can say there are definately many species present. Can any differences be noted between the three sites being sampled? Yes. The preliminary study indicates that there are differences.

SITE 1: Diatoms sparce. Limited number of genera. Specimens generally small. No colonies observed.

SITE 2: Diatoms common/abundant. Good number of genera. Specimens small to extremely large. Colonies observed.

SITE 3: Diatoms common/abundant. Good number of genera. Specimens small to large. Colonies observed.

Between 20 and 30 images have been collected from each site sampled and permanant slides have been made for each site. The images presented above are offered to give a 'broad strokes' feel for the diatom populations at each site.

The diatomic study is already proving to be as much fun as it was hoped it would be. Very educational as well as entertaining (at least for me) and over time the slide collection should become a useful resource for the Woodlands View Education project, as well as for future study by diatom experts. I hope you are also enjoying this journey into the microscopic world of the diatom. Cheerio for now, JK.

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Posted by on in Microscapes

The next installment of the Diatom Survey should be along in the next few days. While you're waiting for it to arrive, here's a little video that is not only entertaining, but I think is also rather thought-provoking.

Diatoms are single-celled organisms that get their energy from the Sun via photosynthesis, so they don't need to hunt for food. If they don't live in colonies where they attach to others of their kind they don't need to search for friends. They reproduce by binary fission, dividing into two daughter cells each with one half of the diatom shell and each daughter then makes the other half for itself, so they don't need to search for a partner.

So why do diatoms move? Even though their meanderings do seem rather aimless there must be some reason for it, but I admit, I cannot come up with a sensible suggestion for it. Perhaps you can. If you know, or find out, then please feel free to contact me: This email address is being protected from spambots. You need JavaScript enabled to view it.

Here are a small collection of motile diatoms. Enjoy.


Tagged in: Diatom
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Posted by on in Microscapes

It's not actually the diatoms that I've been dancing with, but the microscope imaging software has been leading me on a merry dance indeed. Having sorted out the calibration routine I'm now able to measure very accurately in microns, as mentioned previously, but now I find that the images can only be stored as .tft files if they contain measurement data. This type of file does not load into any other program! Grrrr I have, however, managed to find a 'workaround' that works with relative ease and actually produces a better finished result. Yaaay

Another piece of good news is that I've managed to produce my first permanant slide using the Naphrax mountant without setting fire to the house, causing explosions, killing my dog, or any other nastiness. Hopefully this will be the case for all future permanant slide preparations. The Naphrax mountant has a higher refractive index (RI) than glass, water, and diatoms, so the finer details of the diatom shells are now coming into view. These fine structures are important for identification purposes and it shouldn't be too long before I can start placing my specimens into their genera.

Here's an example of some diatoms taken from a wet orange-stained moss on a wall at Woodlands View. Enjoy.


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