Strictly speaking, these are protists, rather than plants, but many people still think of them as plants: after all they do possess chlorophyll for photosynthesis. Of course many have the disconcerting habit of moving around, often quite rapidly, and not very plant-like...
Such slides were especially popular in the 19th century as exhibition pieces to show of both the beauty of the diatoms and also the prowess of the slide maker. It has been said that the ideal tool for arranging diatoms is a tiger's whisker.
Zeiss GFL Microscope
Objective: Zeiss x10 plan
Ocular: Watson x8 Compensating
Darkground: substage wheelstop
Camera: Canon Powershot S50
ISO50, F4.0, 1/640 sec
Diatoms |
Diatoms have long been a favourite subject for microscopists, both for aesthetic and utilitarian reasons. The patterns resulting from their cell-wall structure can be very beautiful, especially if you have a love of patterns and geometry. These patterns can be so fine that they have also provided microscopists with a readily available and cheap means of testing the ability of their instuments to resolve fine detail. The pictures on this page of diatoms are of a mixture of marine and freshwater species. Diatoms are unusual in that as single celled algae they possess cell wals impregnated with silica - effectively the cell walls are made of glass. The cells are made of two halves, "frustules" held together by a kind of belt, called a "girdle". To appreciate the fine patterning, the frustules have to be specially cleaned and mounted for viewing in a highly refractive mountant. The patterns are only poorly visible in live diatoms, largely being obscured by chlorophyll and also by the fact that the refractive index of water is too low for really good resolution. Moiré pattern formed by fine markings in a centric diatomZeiss GFL Microscope Colouration caused by diffraction effects due to the very fine patternsZeiss GFL Microscope |
CoscinodiscusZeiss GFL microscope and at greater magnification: - Zeiss GFL Microscope Another species: Zeiss GFL Microscope
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SynedraA live sample from Dipping Pond 1, Warnham Millpond 25-Apr-2004 Watson Bactil Binocular Microscope
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Gyrosigma spA common freshwater species Microscope: Zeiss Standard GFL
Pleurosigma sp (prepared specimen)A marine species Showing detail of fine markings (inset) Specimen from Dunkirk, USA (thanks, Frez!) Zeiss GFL Microscope
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Unidentified diatomGirdle and plan views (but which is which?) Zeiss GFL Microscope
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Sceptroneis sp.Specimen from Dunkirk, USA (also from Frez) Zeiss GFL Microscope |
Triceratium sp (?)Zeiss GFL microscope Sample from Dunkirk, Maryland |
ActinoptychusThis is a composite of 30 images. A rough template was first composed using CombineZ, then each of the in-focus parts of the original images was cloned onto the template using Paint Shop Pro 9. The original specimen is on a slide, provided by Frez, of diatoms from Dunkirk, Maryland. This particular individual was in the mounting medium at an angle, thus permitting a composite image showing the 3D layout of the diatom. Zeiss GFL Microscope ...and in plan view: Zeiss GFL Microscope
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... and finally for Actinoptychus, here is a 3D view again, but this time created using Helicon Focus to combine 92 differential interference contrast images: Microscope: Zeiss Standard GFL |
A selection of diatoms in a strew slide of a sample from the Bosphorus SeaZeiss GFL microscope
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DesmidsThese are another type of single celled algae, and again they come in many beautiful forms. |
ClosteriumProjectina Microscope Collected from my garden pond |
Other AlgaePandorinaZeiss GFL Microscope Sample from Boldings Brook surface film (Warnham Millpond, Hosrham, UK) 10 July 2005 |
SpyrogyraZeiss Standard GFL Microscope
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Synura uvella(?)This is a rather like a spherical cluster of grapes, each one of which has a flagellum. The whole colony swims with a rolling motion, tumbling through the water. Microscope: Zeiss Standard 18
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Phacus, a Euglenid algaMicroscope: Zeiss Standard 18 The dark spot at the left end of the organism is in fact a red eye spot
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Gonium pectoraleThis is a free swimming algal colony, usually of 16 cells, the inset shows the colony in motion, and the flagella can be seen that provide propulsion Microscope: Zeiss Standard GFL
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Coleochaete scutataMicroscope: Zeiss Standard GFL
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