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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
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The frustules of dead diatoms drift to the ocean floor where, over millions of years, they can build up as much as half a mile deep. [16] Diatoms uses silicon in the biogenic silica (BSiO 2) form, [17] which is taken up by the silicon transport protein to be predominantly used in constructing these protective cell wall structures. [18]
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 .
In a small group of dinoflagellates, called 'dinotoms' (Durinskia and Kryptoperidinium), the endosymbionts (diatoms) still have mitochondria, making them the only organisms with two evolutionarily distinct mitochondria. [119] In most of the species, the plastid genome consist of just 14 genes. [120]
Thalassiosira pseudonana is a species of marine centric diatoms.It was chosen as the first eukaryotic marine phytoplankton for whole genome sequencing. [1] T. pseudonana was selected for this study because it is a model for diatom physiology studies, belongs to a genus widely distributed throughout the world's oceans, and has a relatively small genome at 34 mega base pairs.
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.
Diatoms are enclosed in protective silica (glass) shells called frustules. Each frustule is made from two interlocking parts covered with tiny holes through which the diatom exchanges nutrients and wastes. [156] The frustules of dead diatoms drift to the ocean floor where, over millions of years, they can build up as much as half a mile deep. [160]