Fragilariopsis kerguelensis

Fragilariopsis kerguelensis,^[1] is a pennate diatom native to the Southern Ocean. It has been characterized as "the most abundant diatom in the Antarctic Seas".^[2]

Fragilariopsis kerguelensis
Scientific classification
Domain:	Eukaryota
Clade:	Diaphoretickes
Clade:	SAR
Clade:	Stramenopiles
Phylum:	Gyrista
Subphylum:	Ochrophytina
Class:	Bacillariophyceae
Order:	Bacillariales
Family:	Bacillariaceae
Genus:	Fragilariopsis
Species:	F. kerguelensis
Binomial name
Fragilariopsis kerguelensis (O'Meara) Hustedt
Synonyms
Terebraria kerguelensis Fragilaria antarctica Fragilaria kerguelensis Fragilariopsis antarctica Nitzschia kerguelensis Terebraria kerguelensis Trachysphenia australis var. kerguelensis

Description

Fragilariopsis kerguelensis is a unicellular, phototrophic, microalga with a range in size of 10 - 80 μm.^[3] It is encased in a heavily silicified cell wall, called the frustule, and is identified by its unique theca, raphe and striations, which distinguish it from other diatoms.^[4] They are native to pelagic environments of the Southern Ocean within a temperature range of -1° to 18° C.^[5] F. kerguelensis is known to form community chains that consist of 20-100 cells and can be up to 300 μm long.^[6]

Use as a paleoceanographic proxy

Fragilariopsis kerguelensis is well preserved in the fossil record and commonly referenced as a paleoceanographic or paleoclimatic proxy. F. kerguelensis comprises the largest deposit of biogenic silica in the world (~75%) despite only accounting for 20% of global production.^[5][7] It is an open water species and is found in its highest abundance between the Antarctic Circumpolar Current and the Subtropical Front.^[8] This, along with its tendency to increase valve size near polar fronts, makes F. kerguelensis an ideal indicator of paleoclimate polar front or low-carbon, high-silica exporting regimes.^[9][10] Modern assemblages with F. kerguelensis can be used to calculate past sea surface temperature through the use of transfer functions.^[5]

References

1. O'Meara, E (1877). "the diatomaceous gatherings made at Kerguelen's Land". Journal of the Linnean Society, Botany (15): 55–59.
2. Hart, T.J (1942). "Phytoplankton periodicity in Antarctic surface waters". Discovery Rep.
3. Smetacek, V (1999). "Diatoms and the ocean carbon cycle". Protist. 150 (1): 25–32. doi:10.1016/s1434-4610(99)70006-4. PMID 10724516.
4. "Fragilariopsis kerguelensis (O'Meara) Hustedt, 1952". World Register of Marine Species. World Register of Marine Species.
5. Zielinski, U; Gersonde, R (1997). "Diatom distribution in Southern Ocean surface sediments (Atlantic sector): Implications for paleoenvironmental reconstructions". Palaeogeography, Palaeoclimatology, Palaeoecology. 129 (3–4): 213–250. Bibcode:1997PPP...129..213Z. doi:10.1016/s0031-0182(96)00130-7.
6. Smetacek, V; Assmy, P; Henjes, J (2004). "The role of grazing in structuring Southern Ocean pelagic ecosystems and biogeochemical cycles". Antarctic Science. 16 (4): 541–558. Bibcode:2004AntSc..16..541S. doi:10.1017/s0954102004002317. S2CID 131176101.
7. Verity, P.G; Smetacek, V (1996). "Organism life cycles, predation, and the structure of marine pelagic ecosystems". Marine Ecology Progress Series. 130 (1): 231–250. Bibcode:1996MEPS..130..277V. doi:10.3354/meps130277.
8. Crosta, X; Romero, O; Armand, L.K; Pichon, J.J (2005). "The biogeography of major diatom taxa in Southern Ocean sediments: 2. Open ocean related species". Palaeogeography, Palaeoclimatology, Palaeoecology. 223 (1): 6–92. Bibcode:2005PPP...223...66C. doi:10.1016/j.palaeo.2005.03.028.
9. Cortese, G; Gersonde, R (2007). "Morphometric variability in the diatom Fragilariopsis kerguelensis: Implications for Southern Ocean paleoceanography" (PDF). Earth Planet. Sci. Lett. 257 (3–4): 526–544. Bibcode:2007E&PSL.257..526C. doi:10.1016/j.epsl.2007.03.021.
10. "Profile: Fragilariopsis kerguelensis - Biota - Confluence". SOKI Wiki. Antarctic Climate and Ecosystems Co-operative Research Centre.