Fragilariopsis cylindrus

Fragilariopsis cylindrus
Scientific classification
Domain:	Eukaryota
Clade:	Diaphoretickes
Clade:	SAR
Clade:	Stramenopiles
Phylum:	Gyrista
Subphylum:	Ochrophytina
Class:	Bacillariophyceae
Order:	Bacillariales
Family:	Bacillariaceae
Genus:	Fragilariopsis
Species:	F. cylindrus
Binomial name
Fragilariopsis cylindrus (Grunow ex Cleve) Helmcke & Krieger 1954[1]
Synonyms[2]
Fragilaria cylindrus Grunow ex Cleve 1883 Fragilaria nana Steemann-Nielsen 1935 Fragilariopsis cylindrus var. planctonica Willi Krieger 1954 Fragilariopsis cylindrus f. minor Manguin 1960 Fragilariopsis linearis var. intermedia Manguin 1960 Nitzschia cylindrus (Grunow ex Cleve) Hasle 1972

Fragilariopsis cylindrus[3] is a sympagic (associated with sea ice) and/or planktonic bipolar pennate diatom that can form bloom in spring.[4][5] This psychrophilic unicellular eukaryotic microalgae is an indicator of polar waters and the ecosystem associated with sea ice.[6] It is a model organism to understanding the ecophysiological and fundamental mechanisms of cold-adapted life.[7][8]

Description

Fragilariopsis cylindrus is a pennate raphid diatom with a retangular cell with an elongated apical valve ranging from 15 to 55 μ and a transapical axis ranging from 2.4 to 4 μm.[9] Like other diatoms, F. cylindrus presents a cell wall composed of two biogenic silica valves, the frustule. It is also possible to note the presence of an eccentric raphe canal stretched by fibulae. The cell is generally presents two chloroplasts distributed at each pole of the cell surrounding the cell nucleus.

Life style

Fragilariopsis cylindrus is cracterised by a predominantly chain-formed colonial lifestyle and builds large populations at the bottom of sea ice (sea-ice water interface), as well as in the sea-ice margin zone which includes open water.[6][4] It is known for its success in growing at temperatures below 0°C and has an optimum growth temperature of 4-5°C and an letal limit of ≤ +10°C.[10] As a sympagic microalgae, F. cylindrus can cope with a high salinity environment, typically found in brine channels, by producing large amounts of polysaccharide-rich extracellular polymeric substances (EPS).[11]

F. cylindrus is a phototropic organism, but is able to sustain essential metabolic processes in the dark, ensuring rapid recovery upon re-illumination, and allowing them to survive long-term darkness.[12]

References

1. Helmcke, J.-G. & Krieger, W. (1954). Diatomeenschalen im Elektronenmikroskopischen Bild. Bild u. Forsch. Abt. Biol. Berlin-Wilmersdorf 2: 1–24, pls 103–200.
2. M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org/search/species/detail/?species_id=38075 ; searched on 06 December 2019.
3. Cefarelli, Adrián O.; Ferrario, Martha E.; Almandoz, Gastón O.; Atencio, Adrián G.; Akselman, Rut; Vernet, María (16 October 2010). "Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: morphology, distribution and abundance". Polar Biology. 33 (11): 1463–1484. doi:10.1007/s00300-010-0794-z.
4. Kang, Sung-Ho; Fryxell, Greta A. (1992-11-01). "Fragilariopsis cylindrus (Grunow) Krieger: The most abundant diatom in water column assemblages of Antarctic marginal ice-edge zones". Polar Biology. 12 (6): 609–627. doi:10.1007/BF00236984. ISSN 1432-2056.
5. Tammilehto, Anna; Watts, Phillip C.; Lundholm, Nina (2017). "Isolation by Time During an Arctic Phytoplankton Spring Bloom". Journal of Eukaryotic Microbiology. 64 (2): 248–256. doi:10.1111/jeu.12356. ISSN 1550-7408.
6. Quillfeldt, Cecilie H. von (2004). "The Diatom Fragilariopsis cylindrus and Its Potential As an Indicator Species for Cold Water Rather Than for Sea Ice". Vie et Milieu / Life & Environment (in French): 137.
7. Mock, Thomas; Otillar, Robert P.; Strauss, Jan; McMullan, Mark; Paajanen, Pirita; Schmutz, Jeremy; Salamov, Asaf; Sanges, Remo; Toseland, Andrew; Ward, Ben J.; Allen, Andrew E.; Dupont, Christopher L.; Frickenhaus, Stephan; Maumus, Florian; Veluchamy, Alaguraj (January 2017). "Evolutionary genomics of the cold-adapted diatom Fragilariopsis cylindrus". Nature. 541 (7638): 536–540. doi:10.1038/nature20803. ISSN 1476-4687.
8. Otte, Antonia; Winder, Johanna C.; Deng, Longji; Schmutz, Jeremy; Jenkins, Jerry; Grigoriev, Igor V.; Hopes, Amanda; Mock, Thomas (2023). "The diatom Fragilariopsis cylindrus: A model alga to understand cold-adapted life". Journal of Phycology. 59 (2): 301–306. doi:10.1111/jpy.13325. ISSN 1529-8817.
9. Cefarelli, Adrián O.; Ferrario, Martha E.; Almandoz, Gastón O.; Atencio, Adrián G.; Akselman, Rut; Vernet, María (2010-11-01). "Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: morphology, distribution and abundance". Polar Biology. 33 (11): 1463–1484. doi:10.1007/s00300-010-0794-z. ISSN 1432-2056.
10. Fiala, Michel; Oriol, Louise (1990-10-01). "Light-temperature interactions on the growth of Antarctic diatoms". Polar Biology. 10 (8): 629–636. doi:10.1007/BF00239374. ISSN 1432-2056.
11. Aslam, Shazia N; Strauss, Jan; Thomas, David N; Mock, Thomas; Underwood, Graham J C (2018-05-01). "Identifying metabolic pathways for production of extracellular polymeric substances by the diatom Fragilariopsis cylindrus inhabiting sea ice". The ISME Journal. 12 (5): 1237–1251. doi:10.1038/s41396-017-0039-z. ISSN 1751-7362. PMC 5932028.
12. Kennedy, Fraser; Martin, Andrew; Bowman, John P.; Wilson, Richard; McMinn, Andrew (7 May 2019). "Dark metabolism: a molecular insight into how the Antarctic sea-ice diatom Fragilariopsis cylindrus survives long-term darkness". New Phytologist. 223 (2): 675–691. doi:10.1111/nph.15843. PMC 6617727. PMID 30985935.