Aphanizomenon

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Aphanizomenon
Aphanizomenon colony fluorescence microscopy.jpg
Aphanizomenon flos-aquae
Scientific classification e
Domain: Bacteria
Phylum: Cyanobacteria
Class: Cyanophyceae
Order: Nostocales
Family: Aphanizomenonaceae
Genus: Aphanizomenon
A.Morren ex Bornet & Flahault, 1888
Species

Aphanizomenon flos-aquae Aphanizomenon gracile Aphanizomenon issatschenkoi Aphanizomenon ovalisporum

Aphanizomenon is an important genus of cyanobacteria that inhabits freshwater lakes and can cause dense blooms. Studies on the species Aphanizomenon flos-aquae have shown that it can regulate buoyancy through light-induced changes in turgor pressure.[1] It is also able to move by means of gliding, though the specific mechanism by which this is possible is not yet known.

Ecology[edit]

Overcoming phosphate limitation[edit]

Aphanizomenon may become dominant in a water body partially due to their ability to induce phosphate-limitation in other phytoplankton while also increasing phosphate availability to itself through release of cylindrospermopsin.[2] The cylindrospermopsin causes other phytoplankton to increase their alkaline phosphatase activity, increasing inorganic phosphate availability in the water to Aphanizomenon during times when phosphate becomes limiting.

Nitrogen fixation[edit]

Aphanizomenon is capable of producing biologically-useful nitrogen (ammonium) by the process of nitrogen fixation from atmospheric nitrogen by use of specialized cells called heterocysts.

A large proportion (between 35-50%) of fixed nitrogen may be released into the surrounding water, providing an important source of biologically-available nitrogen to the ecosystem.[3][4]

Toxin production[edit]

Aphanizomenon species may produce cyanotoxins aside from cylindrospermopsin, including anatoxin-a, saxitoxin and BMAA.[5]

Colony formation[edit]

Aphanizomenon may form large colonies as a defense against herbivore grazing, especially Daphnia in freshwater. [6]

See also[edit]

References[edit]

  1. ^ Konopka, A.; T. D. Brock; A. E. Walsby (1978). "Buoyancy regulation by planktonic blue-green algae in Lake Mendota, Wisconsin". Arch. Hydrobiol. 83: 524–537.
  2. ^ Yehonathan Bar-Yosef; Assaf Sukenik; Ora Hadas; Yehudit Viner-Mozzini & Aaron Kaplan (2010). "Enslavement in the Water Body by Toxic Aphanizomenon ovalisporum, Inducing Alkaline Phosphatase in Phytoplanktons". Current Biology. 20 (17): 1557–1561. doi:10.1016/j.cub.2010.07.032. PMID 20705465.
  3. ^ Adam, B.; Klawonn, I.; Svedén, J. B.; Bergkvist, J.; Nahar, N.; Walve, J.; Littmann, S.; Whitehouse, M. J.; Lavik, G.; Kuypers, M. M.; Ploug, H. (2015). "N2-fixation, ammonium release and N-transfer to the microbial and classical food web within a plankton community". The ISME Journal. 10 (2): 450–459. doi:10.1038/ismej.2015.126. PMC 4737936. PMID 26262817.
  4. ^ Ploug, Helle; Musat, Niculina; Adam, Birgit; Moraru, Christina L.; Lavik, Gaute; Vagner, Tomas; Bergman, Birgitta; Kuypers, Marcel M M. (2010). "Carbon and nitrogen fluxes associated with the cyanobacterium Aphanizomenon sp. in the Baltic Sea". The ISME Journal. 4 (9): 1215–1223. doi:10.1038/ismej.2010.53. PMID 20428225.
  5. ^ "Cyanobacteria/Cyanotoxins". US EPA. 2015.
  6. ^ "Aphanizomenon blooms: alternate control and cultivation by Daphnia pulex" (PDF). American Society of Limnology and Oceanography Special Symposium No. 3: 299-304. 1980.

Guiry, M.D.; Guiry, G.M. (2008). "Aphanizomenon". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.