Nannochloropsis

Nannochloropsis
Nannochloropsis viewed under a light microscope
Scientific classification
Domain:	Eukaryota
Kingdom:	Chromalveolata
Phylum:	Heterokontophyta
Class:	Eustigmatophyceae
Family:	Eustigmataceae
Genus:	Nannochloropsis Hibberd, 1981

Nannochloropsis is a genus of alga comprising approximately 6 species. The genus in the current taxonomic classification was first termed by Hibberd (1981). The species have mostly been known from the marine environment but also occur in fresh and brackish water. All of the species are small, nonmotile spheres which do not express any distinct morphological features, and cannot be distinguished by either light or electron microscopy. The characterisation is mostly done by rbcL gene and 18S rDNA sequence analysis. It is different from other related microalgae in that it lacks chlorophyll b and c. Nannochloropsis is able to build up a high concentration of a range of pigments such as astaxanthin, zeaxanthin and canthaxanthin. The algae have a very simple ultrastructure, and reduced compared to neighbouring taxa. They have a diameter of about 2 micrometers. It is considered a promising alga for industrial applications because of its ability to accumulate high levels of polyunsaturated fatty acids. It is mainly used as an energy-rich food source for fish larvae and rotifers. Recently, Nannochloropsis has been investigated for biofuel production. (see Nannochloropsis and biofuels). Restaurant "A Poniente" of El Puerto de Santa María (Cádiz, Spain) is using Nannochloropsis gaditana for human food.

Species

The species currently recognised are:

• N. gaditana
• N. granulata
• N. limnetica
• N. oceanica
• N. oculata
• N. salina

Notes

References

• Andersen, R. A., R. W. Brett, et al. (1998). "Phylogeny of the Eustigmatophyceae based upon 18s rDNA, with emphasis on Nannochloropsis." Protist 149(1): 61-74.
• Assaf Sukenik, Y. C. T. B. (1989). "Regulation of fatty acid composition by irradiance level in the Eustigmatophyte Nannochloropsis sp." Journal of Phycology 25(4): 686-692.
• Hibberd (1981). "Notes on the taxonomy and nomenclature of the algal classes Eustigmatophyceae and Tribophyceae (Synonym Xanthophyceae)." Botanical journal of the Linnean society 82: 93-119.
• Fawley (2007). "Observations on the Diversity and Ecology of Freshwater Nannochloropsis (Eustigmatophyceae), with Descriptions of New Taxa." Protist 158: 325-336.
• Guiry, M.D.; Guiry, G.M. (2008). "Nannochloropsis". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org/search/genus/detail/?genus_id=44568. Retrieved 2009-02-21.