Overview
In , Prasinophytes are a class of the Division Chlorophyta. These are primitive eukaryotic, marine green algae.2] Its best known genus is Ostreococcus (seen at right), which is considered to be the smallest (ca. 0.95 µm) free-living eukaryote[3] and which has been detected in marine samples around the world. Prasinophytes are thought to have low cellular complexity, that is, they are naked cells that possess single, multiple or no flagellae and contain only a single chloroplast and a single mitochondrion. They also have very small genomes for a eukaryote (about 12Mbp).
It has been suggested that a prasinophyte-like flagellate was the ancestor to Chlorophyta and Streptophyta.[4]
Ecology
A study of photosynthetic gene-sequence diversity (rbcL) in the Gulf of Mexico indicated that Prasinophytes are particularly prevalent at the Subsurface Chlorophyll Maximum (SCM)[5] and several different ecotypes of Ostreococcus have been detected in the environment.[6] These ecotypes are distinguished by their adaptation to light intensities. O. lucimarinus is found in high-light environments and represents surface-isolated strains. RCC141 is considered low-light, because these strains were isolated from the lower euphotic zone. O. tauri was isolated from a coastal lagoon and is considered light-polyvalent. Genetic data indicates that distinct molecular differences exist between the different ecotypes that have been detected.[7]
Taxonomy
The Class Prasinophyceae is further organized into finer groupings including:
- Subclass (1): Biddulphiophycidae
- Order (4): Chlorodendrales · Mamiellales · Not Assigned · Pyramimonadales
- Species: ZipcodeZoo has pages for 68 species and subspecies in the Class Prasinophyceae.
Orders
Chlorodendrales
In , the Chlorodendrales are an order of green algae, specifically the Prasinophyceae (prasinophytes). [more]
Mamiellales
In , the Mamiellales are an order of green algae, specifically the Prasinophyceae (prasinophytes). [more]
Not Assigned
Pyramimonadales
In , the Pyramimonadales are an order of green algae, specifically the Prasinophyceae (prasinophytes). [more]
At least 57 species and subspecies belong to the Order Pyramimonadales.
More info about the Order Pyramimonadales may be found here.
References
- ^ Guiry, M.D. & Guiry, G.M. (2007). "Class: Prasinophyceae taxonomy browser". AlgaeBase version 4.2 World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org/browse/taxonomy/?id=4345. Retrieved on 2007-09-23.
- ^ Sym SD, Pienaar RN (1993). "The class Prasinophyceae". Prog Phycol Res 9: 281–376.
- ^ Courties C, Vaquer A, Troussellier M, Lautier J, Chrétiennot-Dinet MJ, Neveux J, Machado C, Claustre H (1994). "Smallest eukaryotic organism". Nature 370: 255. doi:
- ^ Kapraun DF (April 2007). "Nuclear DNA content estimates in green algal lineages: chlorophyta and streptophyta". Ann. Bot. 99 (4): 677–701. doi:
- ^ Wawrik B, Paul JH, Campbell L, Griffin D, Houchin L, Fuentes-Ortega A, Müller-Karger F (2003). "Vertical Structure of the Phytoplankton Community Associated with a Coastal Plume in the Gulf of Mexico". Marine Ecology Progress Series 251: 87–101. doi:
- ^ Guillou L, Eikrem W, Chrétiennot-Dinnet MJ, Le Gall F, Massana R, Romari K, Pedros-Alio C, Vaulot D (2004). "Diversity of picoplanktonic Prasinophyceae assessed by direct SSU rDNA sequencing of environmental samples and novel isolates retrieved from oceanic and coastal marine ecosystems". Protist 155: 193–214. doi:
- ^ Rodríguez F, Derelle E, Guillou L, Le Gall F, Vaulot D, Moreau H (2 005). "Ecotype diversity in the marine picoeukaryote Ostreococcus (Chlorophyta, Prasinophyceae)". Environmental Microbiology 7: 853–859. doi:
Sources
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