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An example of proxies is the use of diatom isotope records of δ13C, δ18O, δ30Si (δ13C diatom, δ18O diatom, and δ30Si diatom). In 2015, Swann and Snelling used ...
Diatoms belong to a large group called the heterokonts, which include both autotrophs such as golden algae and kelp; and heterotrophs such as water moulds.The classification of heterokonts is still unsettled: they may be designated a division, phylum, kingdom, or something intermediate to those.
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.
Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (for example, Oodinium and Pfiesteria). Some dinoflagellates produce resting stages, called dinoflagellate cysts or dinocysts , as part of their lifecycles; this occurs in 84 of the 350 described freshwater species and a little more than 10% of the ...
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 .
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]
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Diatoms generate about 20 per cent of all oxygen produced on the planet each year, [26] and take in over 6.7 billion metric tons of silicon each year from the waters in which they live. [57] They produce 25–45% of the total primary production of organic material in the oceans, [ 58 ] [ 59 ] [ 60 ] owing to their prevalence in open-ocean ...