Diatoms have two distinct shapes: a few (centric diatoms) are radially symmetric, while most (pennate diatoms) are broadly bilaterally symmetric. A unique feature of diatom anatomy is that they are surrounded by a cell wall made of silica (hydrated silicon dioxide), called a frustule.
Diatoms are also used extensively in palaeoenvironmental studies particularly in palaeoceanography. Dissolution of diatom frustules during descent through the water column, on the sediment surface and during diagenesis may seriously alter the preserved assemblage by preferentialy dissolving more lightly silicified forms.
Click for a diagram of Navicula. Brightfield, x Keep in mind that the cutaway diagram of a diatom is a very generalized schematic and cannot adequately describe the variation in all diatoms. As the image of Coscinodiscus shows, diatom chloroplasts are usually yellowish-brown in color, ranging between yellowish-green and dark brown.
The number and shape of chloroplasts varies greatly between different species of diatoms and Coscinodiscus contains many more smaller chloroplasts than shown in our schematic diagram above. Keep in mind that the cutaway diagram of a diatom is a very generalized schematic and cannot adequately describe the variation in all diatoms.
ADVERTISEMENTS: In this article we will discuss about the reproduction in basillariophyta. This will also help you to draw the structure and diagram of reproduction in bacillariophyta. Diatom cells multiply usually by a peculiar method of cell division. An increase in the volume of the frustule results in a slight separation of the valves which […]
Diatom Algae, Campylodiscus is a photograph by Power And Syred which was uploaded on March 7th, 2014. The photograph may be purchased as wall art, home decor, apparel, phone cases, greeting cards, and more.
Diatom definition, any of numerous microscopic, unicellular, marine or freshwater algae of the phylum Chrysophyta, having cell walls containing silica. See more.
Diagram showing the diatom mobility using raphe. Cell Division (Asexual Reproduction). Diatoms reproduce asexually by cell division to produce two daugther cells by mitosis; each daughter cell receives one valve and it is reproduced by furrowing. The cell has vesicles that increase the deposition of silica creating a new valve girdle band.
The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer to a single species, Prymnesium parvum, which causes fish kills. The Chrysophyceae should not be confused with the Chrysophyta, which is a more ambiguous taxon.
ADVERTISEMENTS: In this article we will discuss about:- 1. Description of Diatoms 2. Characteristics of Diatoms 3. Classification 4. Occurrence 5. Plant Body 6. Cell Structure 7. Reproduction 8. Economic Importance. Description of Diatoms: It is a large group of algae consisting of 200 genera and over 10,000 species, out of which 92 genera and […]