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Medlin and co-workers erected a new class, Mediophyceae (which could be re-ranked a subclass if diatoms as a whole are ranked as a class rather than a phylum) for the "polar centric" diatoms, which they consider to be more closely related to the pennate rather than to other centric diatoms, a concept which has been followed or further adapted ...
Living diatoms make up a significant portion of the Earth's biomass: they generate about 20 to 50 percent of the oxygen produced on the planet each year, [11] [12] take in over 6.7 billion tonnes of silicon each year from the waters in which they live, [13] and constitute nearly half of the organic material found in the oceans.
Diatoms are eukaryotic organisms in the phylum Bacillariophyta. This page contains articles about diatoms and diatomists.. Older classifications used to subdivide diatoms into Centrales and Pennales (with Bacillariophyceae used as a class), whereas more recent ones use a three classes system: Bacillariophyceae, Coscinodiscophyceae and Fragilariophyceae.
Diatoma is a genus of diatoms belonging to the family Fragilariaceae. [1] The genus has cosmopolitan distribution. [1] Species: [1] Diatoma angusticostata D.M.Williams & Z.Levkov, 2006; Diatoma arcuatum Lyngbye, 1818; Diatoma auritum Lyngbye, 1819; Diatoma elongata
Naviculaceae is a diatom family in the order Naviculales. Naviculaceae are typically composed of lineate areolae, one of the many forms of areolae. Some of the other areolae are punctate (Gomphoneis) and loculate (Diploneis). [1] These can be found among other families of diatoms including Thalassiosiraceae.
As the diatom divides, each daughter retains one theca of the original frustule and produces one new theca. This means that one daughter cell is the same size as the parent (epitheca and new hypotheca) while in the other daughter the old hypotheca becomes the epitheca which together with a new and slightly smaller hypotheca comprises a smaller ...
Navicula diatoms are highly motile and move through a gliding movement [3] [4] [5] This is done through excretion of extracellular polymeric substances (EPS). One form of EPS surrounds the outside of the cell and another is excreted through a slit in the frustule called a raphe, allowing the cell to glide along a track.
Some pennate diatoms also exhibit a fissure along their longitudinal axis. This is known as a raphe, and is involved in gliding movements made by diatom cells; motile diatoms always possess a raphe. In terms of cell cycle , vegetative cells are diploid and undergo mitosis during normal cell division .