diatom

di·a·tom

D0201100 (dī′ə-tŏm′)n. Any of various microscopic one-celled or colonial heterokonts of the class Bacillariophyceae that are photosynthetic, have a silica cell wall made up of two interlocking parts, and form an important component of phytoplankton.

[New Latin diatoma, from Greek diatomos, cut in half, from diatemnein, to cut in half : dia-, dia- + temnein, to cut; see tem- in Indo-European roots.]

diatom

(ˈdaɪətəm; -ˌtɒm) n (Microbiology) any microscopic unicellular alga of the phylum Bacillariophyta, occurring in marine or fresh water singly or in colonies, each cell having a cell wall made of two halves and impregnated with silica. See also diatomite[C19: from New Latin Diatoma (genus name), from Greek diatomos cut in two, from diatemnein to cut through, from dia- + temnein to cut]

di•a•tom

(ˈdaɪ ə təm, -ˌtɒm)

n. any of numerous mostly marine algae of the class Bacillariophyceae (phylum Chrysophyta), each one-celled alga being enclosed in an intricately patterned double shell of silica, one shell fitting over the other like a box lid. [1835–45; < New Latin Diatoma orig. a genus name, feminine n. based on Greek diátomos cut in two. See dia-, -tome]

di·a·tom

(dī′ə-tŏm′) Any of various microscopic one-celled algae that live in water, have hard shells composed mostly of silica, and often live in colonies. Diatom shells are made of two symmetrical parts called valves.

diatomaceous (dī′ə-tə-mā′shəs) adjective

Thesaurus

Noun

diatom - microscopic unicellular marine or freshwater colonial alga having cell walls impregnated with silicaphytoplankton - photosynthetic or plant constituent of plankton; mainly unicellular algaealga, algae - primitive chlorophyll-containing mainly aquatic eukaryotic organisms lacking true stems and roots and leavesBacillariophyceae, class Bacillariophyceae, class Diatomophyceae, Diatomophyceae - marine and freshwater eukaryotic algae: diatoms

Translations

diatomée

diatom

(dī`ətŏm', –tōm'), unicellular organism of the kingdom ProtistaProtista
or Protoctista
, in the five-kingdom system of classification, a kingdom comprising a variety of unicellular and some simple multinuclear and multicellular eukaryotic organisms.
..... Click the link for more information. , characterized by a silica shell of often intricate and beautiful sculpturing. Most diatoms exist singly, although some join to form colonies. They are usually yellowish or brownish, and are found in fresh- and saltwater, in moist soil, and on the moist surface of plants. They carry chlorophylls a and c and the carotenoid fucoxanthin contained in plastids. They reproduce asexually by cell division. Some 40,000 species (5,600 living species) are either bilaterally or radially symmetrical. For the most part they lack flagella. Although most diatoms are autotrophic, some heterotrophic or symbiotic species can be found in particular habitats. The living matter of each diatom is enclosed in a shell of silica that it secretes. These shells are marked by minute pores or depressions that allow the living organism access to its environment. As the principal constituent of plankton (see marine biologymarine biology,
study of ocean plants and animals and their ecological relationships. Marine organisms may be classified (according to their mode of life) as nektonic, planktonic, or benthic. Nektonic animals are those that swim and migrate freely, e.g.
..... Click the link for more information. ), diatoms are an important food source for fish and other aquatic animals, e.g., the baleen whaleswhale,
aquatic mammal of the order Cetacea, found in all oceans of the world. Members of this order vary greatly in size and include the largest animals that have ever lived. Cetaceans never leave the water, even to give birth.
..... Click the link for more information. .

When aquatic diatoms die they drop to the bottom, and the shells, not being subject to decay, collect in the ooze and eventually form the material known as diatomaceous earth (sometimes called kieselguhr). When it occurs in a more compact form as a soft, chalky, light-weight rock, it is called diatomite. Deposits of diatomaceous material, formed underwater in past geologic time and now exposed above water, are found in all parts of the world. Diatomite is much used as an insulating material against both heat and sound, in making dynamite and other explosives, and for filters, abrasives, and similar products. Most of the earth's limestone has been deposited by diatoms, and much petroleum is of diatom origin.

Diatoms are classified in the phylum (division) ChrysophytaChrysophyta
, phylum (division) of unicellular marine or freshwater organisms of the kingdom Protista consisting of the diatoms (class Bacillariophyceae), the golden, or golden-brown, algae (class Chrysophyceae), and the yellow-green algae (class Xanthophyceae).
..... Click the link for more information. , class Bacillariophyceae.

diatom

[′dī·ə‚täm] (invertebrate zoology) The common name for algae composing the class Bacillariophyceae; noted for the symmetry and sculpturing of the siliceous cell walls.

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Words related to diatom

noun microscopic unicellular marine or freshwater colonial alga having cell walls impregnated with silica

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