''Nitzschia'' is a common pennate marine and freshwater

diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

. In the scientific literature, this genus, named after

Christian Ludwig Nitzsch Christian Ludwig Nitzsch (3 September 1782 – 16 August 1837) was a German zoologist. He is best remembered for his approach to classifying birds on the basis of their feather tract distributions or pterylosis of their young. Career He was profe ...

, is sometimes referred to incorrectly as ''Nitzchia'', and it has many species described, which all have a similar morphology. In its current

circumscription Circumscription may refer to: * Circumscribed circle * Circumscription (logic) *Circumscription (taxonomy) * Circumscription theory, a theory about the origins of the political state in the history of human evolution proposed by the American anthr ...

, ''Nitzschia'' is

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

Occurrence

''Nitzschia'' is found mostly in colder waters, and is associated with both

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

and

Antarctic The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antar ...

polar

sea ice Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world' ...

, where it is often found to be the dominant diatom. ''Nitzschia'' includes several species of diatoms known to produce the

neurotoxin Neurotoxins are toxins that are destructive to nervous tissue, nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insult (medical), insultsSpencer 2000 that can adversely affect function ...

known as domoic acid, a toxin responsible for the human illness called

amnesic shellfish poisoning Amnesic shellfish poisoning (ASP) is an illness caused by consumption of shellfish that contain the marine biotoxin called domoic acid. In mammals, including humans, domoic acid acts as a neurotoxin Neurotoxins are toxins that are destructive ...

. The species '' N. frigida'' is found to grow exponentially even at temperatures between −4 and −6 °C. Some ''Nitzschia'' species are also

extremophile An extremophile () is an organism that is able to live (or in some cases thrive) in extreme environments, i.e., environments with conditions approaching or stretching the limits of what known life can adapt to, such as extreme temperature, press ...

s by dint of tolerance to high

salinity Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensio ...

; for example, some

halophilic A halophile (from the Greek word for 'salt-loving') is an extremophile that thrives in high salt concentrations. In chemical terms, halophile refers to a Lewis acidic species that has some ability to extract halides from other chemical species. ...

species of ''Nitzschia'' are found in the

Makgadikgadi Pans The Makgadikgadi Pan (Tswana pronunciation ), a salt pan situated in the middle of the dry savanna of north-eastern Botswana, is one of the largest salt flats in the world. The pan is all that remains of the formerly enormous Lake Makgadik ...

Botswana Botswana, officially the Republic of Botswana, is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory part of the Kalahari Desert. It is bordered by South Africa to the sou ...

.C. Michael Hogan (2008
The Megalithic Portal, ed. A. Burnham
/ref>

Species

The genus ''Nitzschia'' includes more than 1280 species and variants — for more information, see: Some of these are: *'' Nitzschia acicularis'' *'' Nitzschia amphibia'' *'' Nitzschia angustata'' *'' Nitzschia brevissima'' *'' Nitzschia clausii'' * '' Nitzschia communis'' *'' Nitzschia denticula'' *'' Nitzschia disputata'' *'' Nitzschia dissipata'' *'' Nitzschia filiformis'' *'' Nitzschia fonticola'' *'' Nitzschia frigida'' *'' Nitzschia gracilis'' *'' Nitzschia heuflerania'' *'' Nitzschia invisitata'' *'' Nitzschia lacuum'' *'' Nitzschia latens'' *'' Nitzschia palea'' *'' Nitzschia perminuta'' *'' Nitzschia pusilla'' *'' Nitzschia recta'' *'' Nitzschia sigma'' *'' Nitzschia sigmoidea'' *'' Nitzschia sinuata'' *'' Nitzschia tubicola''

References

External links

* Bacillariales Taxa named by Arthur Hill Hassall Diatom genera {{Diatom-stub