Aphanizomenon

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Aphanizomenon
Aphanizomenon colony fluorescence microscopy.jpg
Aphanizomenon flos-aquae
Scientific classification
Kingdom: Bacteria
Phylum: Cyanobacteria
Class: see [1]
Order: Nostocales
Family: Nostocaceae
Genus: Aphanizomenon
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 and Aaron Kaplan (2010). "Enslavement in the Water Body by Toxic Aphanizomenon ovalisporum, Inducing Alkaline Phosphatase in Phytoplanktons". Current Biology. 20: 1557–1561. doi:10.1016/j.cub.2010.07.032. PMID 20705465. 
  3. ^ "N2-fixation, ammonium release and N-transfer to the microbial and classical food web within a plankton community". The ISME Journal. 10: 450–459. 2015. doi:10.1038/ismej.2015.126. 
  4. ^ "Carbon and nitrogen fluxes associated with the cyanobacterium Aphanizomenon sp. in the Baltic Sea". The ISME Journal. 4: 1215–1223. 2010. doi:10.1038/ismej.2010.53. 
  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.